Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference (한국전기전자재료학회:학술대회논문집)
The Korean Institute of Electrical and Electronic Material Engineers
- Annual
2000.11a
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1.8V,4Gb DDR SDRAM설계 및 제작을 수행하였다. DRAM동작 시 발생하는 Bit Line간 CouplingNoise를 보상하기 위한 Twisted Open Bit Line 구조를 제안하였다. Low Voltage Operation으로 인한 Bit Line Sense Amplifier 의 동작 저하를 보상하기 위한 BL S/A Pre-Sensing 방식 및 Reference Bit Line Voltage Calibration 구조를 제안하였다. Chip면적 증가로 인한 동작속도 감소의 보상을 위해 Repeater Driver 구조를 Core 및 Periphery Circuit에 적용하여 동작 대비 Chip 면적의 증가를 최소화 하도록 하였다.
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Insulators for high-voltage and large-power should be endured mechanically the weight of mold bushing itself and the force of pushed from contact with circuit breaker and conductor. But dielectric breakdown could be occurred result from the external circumstances and internal factors such as chemical reaction, partial discharge, change of temperature and the relation of temperature-time in process of casting. Therefore, to get rid of external and internal factors of dielectric breakdown. Furthermore, to prevent the internal cracks, void, cavity which resulted from the contraction originated on the interface between copper and epoxy resin, formed semi-conductive layer with partially carbon painted on copper bar. The PD properties and the insulation qualities of epoxy molded insulators were improved by roles of cushions for the direction of diameter and natural sliding effects as like separated from conductor for the direction of length.
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(PbS)
$_{1-x}$ -(CuS)$_{x}$ thin films(x=0, 0.5, 1) were grown on glass substrates by using a chemical bath deposition method. The molecular ratio of Pb to Cu for the PbS-CuS thin films(x=0.5) was measured about 7:3 by using EDX and XRF. The resistivity of non-annealed (PbS)$_{1-x}$ -(CuS)$_{x}$ thin films was about 10$\Omega$ . cm. However, after annealing, the resistivity of PbS showed a little change, while PbS-CuS and CuS significantly decreased in the range of 0.002 to 0.005$\Omega$ .cm. PbS was p-type and CuS was n-type.-type. -
This study is about a retrograde triple well employed in the Cell tr. of next DRAM and flash memory. Triple well structure is formed deep n-well under the light p-well using MeV ion implantation. MeV P implanted deep n-well was observed to show greatly improved characteristics of electrical isolation and soft error. Junction leakage current, however, showed a critical behavior as a function of implantation and annealing conditions. {311} defects were observed to be responsible for the leakage current. {311} defects were generated near the R
$\_$ p/ (Projected range) region and grown upward to the surface during annealing. This is study on the defect behavior in device region as a function of implantation and annealing conditions. -
Ferroelectric YMnO
$_3$ thin films are excellent dielectric materials for high integrated ferroelectric random access memory (FRAM) with metal-ferroelectric-silicon field effect transistor (MFSFET) structure. In this study, YMnO$_3$ thin films were etched with C1$_2$ /Ar gas chemistries in inductively coupled plasma (ICP). The maximum etch rate of YMnO$_3$ thin films is 285$\AA$ /min under C1$_2$ /Ar of 10/0, 600 W/-200 V and 15 mTorr. The selectivities of YMnO$_3$ over CeO$_2$ and$Y_2$ O$_3$ are 2.85, 1.72, respectively. The results of x-ray photoelectron spectroscopy (XPS) reflect that Y is removed dominantly by chemical reaction between Y and Cl, while Mn is removed more effective by Ar ion bombardment than chemical reaction. The results of secondary ion mass spectrometer (SIMS) were equal to these of XPS. The etch profile of the etched YMnO$_3$ film is approximately 65$^{\circ}$ and free of residues at the sidewall. -
In this study,
$Y_2$ O$_3$ thin films were etched with inductively coupled plasma (ICP). The etch rate of$Y_2$ O$_3$ , and the selectivity of$Y_2$ O$_3$ to YMnO$_3$ were investigated by varying Cl$_2$ /(Cl$_2$ +Ar) gas mixing ratio. The maximum etch rate of$Y_2$ O$_3$ , and the selectivity Of$Y_2$ O$_3$ to YMnO$_3$ were 302/min, and 2.4 at Cl$_2$ /(Cl$_2$ +Ar) gas mixing ratio of 0.2 repectively. In x-ray photoelectron spectroscopy (XPS) analysis,$Y_2$ O$_3$ thin film was dominantly etched by Ar ion bombardment, and was assisted by chemical reaction of Cl radical. These results were confirmed by secondary ion mass spectroscopy(SIMS) analysis. YCI, and YCl$_3$ existed at 126.03 a.m.u, and 192.3 a.m.u, respectively -
Cerium oxide thin film has been proposed as a buffer layer between the ferroelectric film and the Si substrate in Metal-Ferroelectric-Insulator-Silicon (MFIS ) structures for ferroelectric random access memory (FRAM) applications. In this study, CeO
$_2$ thin films were etched with Cl$_2$ /Ar gas combination in an inductively coupled plasma (ICP). The highest etch rate of CeO$_2$ film is 230$\AA$ /min at Cl$_2$ /(Cl$_2$ +Ar) gas mixing ratio of 0.2. This result confirms that CeO$_2$ thin film is dominantly etched by Ar ions bombardment and is assisted by chemical reaction of Cl radicals. The selectivity of CeO$_2$ to YMnO$_3$ was 1.83. As a XPS analysis, the surface of etched CeO$_2$ thin films was existed in Ce-Cl bond by chemical reaction between Ce and Cl. The results of XPS analysis were confirmed by SIMS analysis. The existence of Ce-Cl bonding was proven at 176.15 (a.m.u.). -
Na-K-Nb system showed a number of ferroelectric phases in bulk ceramic. [001]-axis oriented single-phase Na
$_{0.5}$ K$_{0.5}$ NbO$_3$ (NKN) thin film have been grown on LaA1O$_3$ substrates using KrF excimer laser. X-ray diffraction$\theta$ -2$\theta$ scan, rocking curves, and$\phi$ scan data evidence highly c-axis oriented along the [001] direction.ion. -
A small electrical potential difference which appears on any solid body when subjected to illumination by a modulated light beam generated by laser is called photocharge voltage(PCV)[1,2]. This voltage is proportional to the induced change in the surface electrical charge and is capacitatively measured on various materials such as conductors, semiconductors, ceramics, dielectrics and biological objects. The amplitude of the detected signal depends on the type of material under investigation, and on the surface properties of the sample. In photocharge voltage spectroscopy measurements[3], the sample is illuminated by both a steady state monochromatic bias light and the pulsed laser. The monochromatic light is used to created a variation in the steady state population of trap levels in the surface and space charge region of semiconductor samples which does result in a change in the measured voltage. Using this technique the spatial variation of PCV can be utilized to evaluate the surface conditions of the sample and the variation of the PCV due to the monochromatic bias light are utilized to characterize the surface states. A qualitative analysis of the proposed measurement is present along with experimental results performed on amorphous silicon samples. The deposition temperature was varied in order to obtain samples with different structural, optical and electronic properties and measurements are related to the defect density in amorphous thin film.
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In this paper, since the research on the etching of SrBi
$_2$ Ta$_2$ O$_{9}$ (SBT) thin film was few (specially Cl$_2$ -base ), we had studied the surface reaction of SBT thin films using the OES in high density plasma etching as a function of rf power, dc bias voltage, and Cl$_2$ (Cl$_2$ +Ar) gas mixing ratio. It had been found that the etch rate of SBT thin films appeared to be more affected by the physical sputtering between Ar ions and surface of the SBT compared to the chemical reaction in our previous papers$^{1.2}$ . The change of Cl radical density that is measured by the OES as a function of gas combination showed the change of the etch rate of SBT thin films. Therefore, the chemical reactions between Cl radical in plasma and components of the SBT enhance to increase the etch rates of SBT thin films and these results were confirmed by XPS analysis. -
High dielectric (Ba,Sr)TiO
$_3$ thin films were etched in an inductively coupled plasma (ICP) as a function of C1$_2$ /Ar gas mixing ratio. Under Cl$_2$ (20)/Ar(80), the maximum etch rate of the BST films was 400$\AA$ /min and selectivities of BST to Pt and PR were obtained 0.4 and 0.2, respectively. We investigated the etched surface of BST by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and x-ray diffraction (XRD). From the result of XPS analysis, we found that residues of Ba-Cl and Ti-Cl bonds remained on the surface of the etched BST for high boiling point. The surface roughness decreased as Cl$_2$ increases in Cl$_2$ /Ar plasma because of non-volatile etching products. This changed the nature of the crystallinity of BST. From the result of XRD analysis, the crystalliility of etched BST film maintained as similar to as-deposited BST under Ar only and Cl$_2$ (20)/Ar(80). However, (100) orientation intensity of etched BST film abruptly decreased at Cl$_2$ only plasma. It was caused that Cl compounds were redeposited on the etched BST surface and damaged to crystallinity of BST film during the etch process. -
In the current development of magnetic sensors based on the Hall effect, the following two approaches can be distinguished. The first, one tries to build better sensor based on conventional Hall devices. The innovations come through a better understand of the details if the operating principle and secondary effects, and through the application if ever-improving microelectronics technology. In the second approach, one hopes to build better sensors by making use of the Hall effect in active devices, such as magneto-transistors and MAGFET. In this paper, we study magnetic properties of Hall device fabricated with series and parallel multilayers.
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Langmuir-Blodgett(LB) technique is the best candidate for the future molecular electronic devices. But, these molecular thin film devices require the bulk properties that are influenced by the molecular orientations. So, this is of current interest in molecular electronic device fabrications of new materials. In this study, quantitative evaluation of molecular orientation in LB films of PAAS was performed by comparing the absorption intensities of the FT-IR transmission and reflection-absorption spectra and the polarized UV/visible absorption spectra. It was found that the polar angle(
$\theta$ ) of the dipole moment is about 68$^{\circ}$ and the tilting angle of the alkyl chain is about 11.5$^{\circ}$ -
In this paper, study on the properties of the thermal degradated epoxy resin which is used in indoor insulation apparatus is performed to investigate the problems of the decreasing insulation characteristics and crack in the indoor insulation apparatus. As a parameter of variation, SEM, contact angle, surface resistivity, relative dielectric constant and weight loss are measured. As the results of the above measurements, the contact angle and surface resistivity of the epoxy resin has increased to 200
$^{\circ}C$ in but at the above 200$^{\circ}C$ the values have decreased. The relative dielectric constants the thermal treated samples have increased on with the temperature increase. We find the volatile components of the epoxy resin compound has disappeared during thermal degradation by SEM. The insulation properties of the epoxy resin have increased by the 200$^{\circ}C$ but decreased in the above 200$^{\circ}C$ . -
Three kinds of treeing inhibitors are added to investigate the effect on electrical properties of XLPE. The treeing inhibitors are barbituric acid, 4- (4-Nitrophenylazo) resorcinol and 4-(4-Nitrophenylazo) naphthol. Added amount of each treeing inhibitors varied form 0phr to 2.0phr. In order to know the changes of electrical properties, break down strength, tan
$\delta$ , and$\varepsilon$ $_{r}$ were measured. Experimental results showed that electrical properties of each sample was slightly changed by amount of additives.s. -
Polyethylene, has long history and is widely used, was researched due to good electrical properties by many authors. But PE under stress has the critical defects of space charge accumulation and tree growth, so various methods such as catalyst, additives and blend to improve these problems have been execute, of which we selected blending method. As in our previous papers we investigated electrical conduction, dielectric and AC dielectric breakdown characteristics, we did DC dielectric breakdown characteristics in this paper. We selected pure LLDPE, pure EVA and LLDPE films mixed with EVA as specimens, which were mixed with the weight percentages of 50, 60, 70 and 80[wt%] to be thin film. DC applying voltage speed was 500[V/sec]. The relation between dielectric breakdown characteristics and the variations of super structure due to mixing was investigated, and especially trap level at amorphous region, threshold energy increment of conductive electron at free volume were considered.
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In this paper, the electrical properties due to epoxy resin used in transformer of rail road signal are studied. The specimen of epoxy resin was hardened as each 3[h], 4[h], 5[h] in this experiment. In order to measure the conductivity properties, the highmegohm meter is used at temperature 25 to 140[
$^{\circ}C$ ] and applying voltage 100 to 1000[V]. As a result of this experiment, we confirmed that 3[h] specimen is better than the others. -
The performance of insulate materials gets worse with stress time in power system and because this causes lowering of function and accidents in equipment,development and performance improvement of excellent insulate materials are needed to make stable system. In this paper, to study the influence of degradation in XLPE, inner semiconducting layer and outer semiconducting layer, we studied dielectric characteristics at temperature 25∼100[
$^{\circ}C$ ] and frequency 20∼ 1 [MHz] -
In order to determine what influences the interfacial charge in EPDM/XLPE laminates, We used PEA (pulsed electroacoustic) method. Interfacial properties such as space charge accumulation and breakdown strength in crosslinked polyethylene (XLPE)/ethylene-propylene-diene monomer (EPDM) laminates were investigated. Interfacial charge develops when the EPDM is laminated with XLPE. It showed the positive polarity same as the simulation in case on intercase of EPDM/XLPE. In case of coupling agent added silicone oil, as increasing the content of coupling agent, the interfacial charge decreased. Details of the results are given and their origins discussed.
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Influence of Filler Shape on Dielectric & Electric Charge-Discharge Properties of Filled Epoxy ResinIn this paper, we have the investigated the Influence of Filler Shape on Dielectric & Electric Charge-Discharge Properties of Filled Epoxy Resin. In the low frequency range from 50Hz to a few kHz, the magnitude of tan
$\delta$ become larger in the order, NON, RAS, SAS, SCS. The electrical Discharge of RAS measured for 60 min, decreased after 10$^2$ ∼10$^3$ . -
FRP has been used very much as high strength core materials for insulators because of its high strength and good insulation properties. In this study cantilever, tension and torsion stress were simulation along to the unidirection glass fiber. In addition, FRP was made by pultrusion method. This paper proposed the procedure of the finite element model updating and pretest using the commercial finite element code MSC. Nastran. To enhance the efficiency of experimental modal analysis, we proposed the process which is the selection of the locations and the number of measurement points for pre-test.
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Liquid Phase Epitaxy 법을 이용하여 La이 첨가된 YIG(Yitrium Ion Garnet)막을 성장시켰다. X선 회절 분석을 이용하여 La의 첨가량을 변화시키며 제조된 막의 격자상수를 조사한 결과, La의 첨가량이 증가함에 따라 성장된 막의 격자상수도 증가하였으며 Y/La이 20인 경우, 막의 격자상수가 기판으로 사용한 GGG의 격자상수와 일치하였다. VSM(Vibration Sample Magnetometer)를 이용하여 구한 막의 포화자화 값은 La의 첨가량과 관계없이 순수한 YIG의 경우와 같은 값인 1750정도로 거의 일정하였다. FMR(Ferro Magnetic Resonance) 측정장치를 이용한 막의 강자성 공명선폭을 측정결과 막의 공명선폭은 La의 첨가량과 관계없이 모든 경우에 순수한 YIG보다 감소하였다. 실험범위내의 La의 첨가에 대해서 기판과의 격자불일치가 순수한 YIG의 경우보다 감소하기 때문이다. La의 첨가량이 많은 조건에서 성장시킨 막은 공명선폭이 크고 두께의 증가에 따라서 선폭이 증가하였으며, Y/La가 20과 30일 때 성장시킨 막에서는 공명선폭의 절대값도 작고 두께에 따른 공명선폭의 변화도 관찰되지 않았다.
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In this study, we investigated the electromagnetic properties of Mn-Zn ferrite doped with rare earth oxide (Dy
$_2$ O$_3$ , Er$_2$ O$_3$ ). The main composition is 52mo1%${\alpha}$ -Fe$_2$ O$_3$ , 25mol% Mn$_3$ O$_4$ 23mo1% ZnO and doped with them(0.05wt% ∼ 0.25wt%, step:0.05wt%). An experimental process has advanced by conventional ferrimagnetism manufacturing that was prepared by standard ceramic techniques. The XRD pattern of all doped sample were observed spinel and secondary phase. The density of sample were measured nearly constant value. As increased the additive, resistivity, initial permeability and real component of the series complex permeability increased with setting limits each other. In case of Mn-Zn ferrite excess doped with them, resistivity, initial permeability and real component of the series complex permeability decreased and magnetic loss increased in proportion to increasing the additive. -
Bi
$_2$ Sr$_2$ CuO$\sub$ x/(Bi(2201)) thin films are fabricated by atomic layer by layer deposition using ion beam sputtering(IBS) method. During the deposition, 10 %-ozone/oxygen mixture gas of typical 5.0${\times}$ 10$\^$ -5/. Torr is applied with ultraviolet light irradiation for oxidation. XRD and RHEED investigations reveal out that a buffer layer with some different compositions is formed at the early deposition stage of less than 10 units cell and then c-axis oriented Bi(2201) is grown. -
Research for the synthesis of high-temperature polymers by the Photochemical method has been carrying out. The use of cheap and available compounds (viz. benzene, its alkyl, aryl and halogen substitutes, furan and maleic anhydride) subject to ultra violet irradiation resulted in a single stage quantitative yield of about 40 new polymers: polyimide films, enamel insulation, molding materials. At present experimental & industrial lots of wire have been produced. Polymer insulation possesses temperature exploitation range (from -l00
$^{\circ}C$ to +300$^{\circ}C$ ) without significant changing of properties. As a result, new polyimide lacquers for production of a wide number of technical articles, such as polyimide films, fibers, enamel-wires, press-materials have been synthesized. An application field of the polyimides in membrane technology, printing plate and optic electronics manufactures has been outlined. -
High quality BSCCO thin films have been fabricated by means of an ion beam sputtering at various substrate temperatures, T
$\_$ sub/, and ozone gas pressures, PO$_3$ . The correlation diagrams of the BSCCO Phases appeared against T$\_$ sub/ and PO$_3$ are established in the 2212 and 2223 compositional films. In spite of 2212 compositional sputtering, Bi2201 and Bi2223 phases as well as Bi2212 one come out as stable phases depending on T$\_$ sub/ and PO$_3$ . From these results, the thermodynamic evaluations of ΔH and ΔS which are related with Gibbs' free energy change for single Bi2212 or Bi2223 phase are performed. -
Bi2212 and Bi2223 thin films are fabricated by ion beam sputtering method. Three phases of Bi2201, Bi2212 and Bi2223 appear as stable ones in spite of the condition for thin film fabrication of Bi2212 and bi2223 compositions, depending on substrate temperature(T
$\sub$ sub/) and ozone pressure (PO$_3$ ). It is found out that these phases show similar T$\sub$ sub/ and PO$_3$ dependence, and that the stable regions of these phases are limited within very narrow temperature. -
In this work the results of the systematic investigations on the effect of organic addition by using polymer compound as starting materials on the superconducting properties of YBCO electrophoretic deposited films on silver substrate are presented. The characteristics of the films were examined by X-ray diffraction and SEM observation. Our results show that the adhesion and microstructure of these films are sensitive to the nature of polymer compounds and sintering conditions (electrophoretic deposition, drying and heat-treatment procedures). To develop optimum microstructures for samples processed in this manner it is necessary to have an understanding of how these processes affect the microstructure and hence the properties of ceramic superconductors.
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The advantage of plasma-sprayed coating is their good resistance against thermal shock due to the porous state of the coated layer with a consequently low Youngs modules. However, the existence of many pores with a bimodal distribution and a laminar structure in the coating reduces coating strength and oxidation protection of the base metals. In order to counteract these problems, there have been many efforts to obtain dense coatings by spraying under low pressure or vacuum and by controlling particle size and morphology of the spraying materials. The aim of the present study is to survey the effects of the HIP treatment between 1100 and 130
$0^{\circ}C$ on plasma-sprayed oxide coating of A1$_2$ O$_3$ , A1$_2$ O$_3$ -SiO$_2$ on the metal substrate (type C18N10T stainless steel). These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing, These results show that high-pressure treatment has an advantage for improving adhesive strength and Vickers hardness of plasma- sprayed coatings. -
This paper reports a newly developed sol-gel process to synthesize dense YBCO thick films with
$BaTiO_3$ additives using electrophoretic deposition and metal alkoxide sol/particle suspension, which we successfully produce dense$YBCO+BaTiO_3$ ceramics at a rather low temperature, compared with the sintering temperature used in conventional methods. The thick films of HTS were prepared by electrophoretic deposition, using pre-sintered powder with barium titanate addition in the form of$BaTi(OR)_6$ solution in suspension for electrophoresis. The conditions for applied voltage and deposition times for electrophoretic deposition of HTS thick films were studied in detail. -
The high Tc phase disappeared and low Tc phase increased in the substitution of transition elements for Bi ions. The high Tc phase decreased in the substitution of Si and Sn for Bi ions. The high Tc phase increased in the substitution of Sb, As and P which were the same group of Bi for Bi ions. The substitution of P ions was the most effective and then the high Tc phase was formed in large quantity by replacing Bi ions with 30% of P ions.
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Perdeuterated hexafluoroacetylacetonato -ytterbium [
$Yb (HFA -D) ] complexes were synthesized by the koto-enol tautomerism reaction of$_3$ _3$$Yb(HFA-H)_3$ in methanol-$d_4$ , in order to reduce the radiationless transition to the ligands. The luminescence properties of$Yb(HFA-D)_3$ complex were measured in the following anhydrous deuterated organic solvents : Acetone-$d_6$ , Methanol-$d_4$ , THF-$d_8$ ,$PO(OC and DMSO-$H_3$ )_3$$d_6$ . The intensity, lifetime and quantum efficiency of the luminescence in DMSO-$d_6$ were superior to those in other deuterated solvents. It was suggested that the anhydrous DMSO-d$_{6}$ might be the most appropriate solvent for the liquid laser material of$Yb(HFA-D)_3$ complex.x. -
We investigated the improvement of viewing angle using a patterned double twisted (PDT) vertical-alignment (VA) cell mode on a homeotropic alignment layer. Good voltage-transmittance curves for negative dielectric anisotropic nematic liquid crystal (NLC) using the PDT-VA cell without a negative compensation film were obtained. The viewing angle of the PDT-VA cell without a negative compensation film was wider than that of a conventional VA cell.
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Synthesis of a new copoly (M4Ch-ChMA), copoly ((4-methacryloyloxy) chalcone-cholestery methacrylate), with chalconyl and cholesteryl moiety characteristics for photoalignment materials was investigated. Good thermal stabilities of the synthesized copolymers are confirmed by thermogravimetric analysis (TGA) measurement. The pretilt angles of the nematic liquid crystal (NLC) are reduced as UV exposure time is increased on the copolymer surfaces. A pretilt angle of 81
$^{\circ}$ in NLC was observed with UV exposure of 3 min on the copolymer-3 surface. The NLCs pretilt angle is attributable to increased chalcone with increasing the UV exposure time. -
New photo-alignment materials based on PCEMA (Poly (4-methacryloyloxylchalcone)) for liquid crystal (LC) aligning were synthesized. And the electro-optical (EO) characteristics of the photo-aligned TN-LCD were investigated. The excellent LC alignment and voltage-transmittance (V-T) characteristics for the photo-aligned TN-LCD on PCEMA surface containing more cinnamoly group can be achieved. However, the reverse tilt disclinations for the photo-aligned TN-LCD on the PCEMA surface containing more OH group were observed. Consequently, we suggest that the LC aligning capabilities can be increased by increasing of cinnamoly group on the PCEMA surfaces.
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In contrast to the
$\pi$ -conjugated polymers which typically absorb light only in the visible spectral region, the$\sigma$ -conjugated polymers can be used as efficient material absorbing light in the UV region. In this work, the electronic and optical properties of I$_2$ -doped$\sigma$ -conjugated poly (methyl-phenylsilylene) (PMPSi) polymer were investigated. DC conductivity up to 1.2$\times$ 10$^{-4}$ S/cm was obtained by I$_2$ -doping. In UV/Vis absorbance spectrum, a new peak was observed near 370 nm, which was explained by polaron model. The photoluminescence (PL) intensity decreased with increasing degree of I$_2$ -doping, and the Infrared (IR) spectrum analysis revealed that the dopants are not directly coupled to the polymer, but effect motions of the methyl and phenyl groups. -
AC impedance measurements on poly-p-phenylenevinylene (PPV) LEDs in the frequency range between 10 Hz and 10
$\^$ 6/ Hz were carried out. The complex-plane impedance spectra indicate that PPV devices can be represented by equivalent circuits that corresponds to the bulk and interfacial regions at high and low frequencies, respectively. As a result of complex impedance analysis through the separation of bulk and interfacial region impedances, increase of forward bias in Al/PPV/ITO devices gave rise to relative decrease of the interfacial region impedance. Above the electric field of 10$\^$ 6/ V/cm the PPV device showed a space charge limited current (SCLC) conduction. The dependence of the transport mechanism and dielectric properties on the applied bias voltage is discussed. -
To reduce the maintenance expense, and the possibility of electric outage and accident, we should optimize the outdoor insulation system. And for the optimization, accurate measurement for the degree of contamination with climatic conditions, such as wind, rain, and drought, should be carried. However the classical measuring method, brush wiping, has some problems in the aspect of man power, reliability, and expense. In this paper, we propose two type apparatus, which could detect the degree of contamination on insulators in outdoor insulation system, such as transmission and distribution line insulator and bushing. One use the leakage current, and the other use the oscillating frequency to check the degree of contamination. To avoid the oxidation of electrode AC source, and the low degree of contamination was applied. From the result of this investigation we could get the good relationship between the degree of contamination and the leakage current and oscillating frequency
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Blue phosphor of Ba-Mg-Al-O:Eu
$^{2+}$ phase was fabricated by conventional firing techniques under reducing atmosphere and its photoluminescence properties are studied with varying Eu concentration and phost-annealing temperature under air atmosphere. This phosphors were well crystallized with particle size in the range of 3~5um and emitted a blue light at a dominent wavelength 450nm for 254nm UV irradiation. The concentration quenching wit Eu$^{2+}$ was that with increasing Eu concentration the energy transfer between the activator ions steadily improves, so that the excitation energy is transported over larger distances through the lattice before luminescence can occur. Thermal quenching also occurred in this phosphor means that in a host lattice with the$\beta$ -alumina structure the bond of an Eu$^{2+}$ ion with the nearest-neighbour oxygen ion is much stronger than in a lattice with the magnetoplumbite structure.cture. -
To investigate the effect of metal electrode in electroluminescent[EL] devices, we fabricated EL devices of ITO/P3HT/Al, ITO/P3HT/LiF/Al and ITO/P3HT/Mg:In structure. In current-voltage-light power characteristics, turn-on voltage of EL devices using LiF insulating layer and Mg:In(2.8V) metal electrode is lower than EL device using Al(4.2V). Besides the external quantum efficiency is improved also. The reason is related to carrier mobility and carrier injection, which would affect the hole-electron balance. In the device with Al electrode, holes injected from indium-tin-oxide[ITO] to poly(3-hexylthiophene)[P3HT] might reach the Al electrode without interacting with injected electrons, because the electron injection efficiency was very low for this electrode. Besides oxidation of the Al electrode is likely due to holes reaching the cathode without meeting injected electrons. Another possible reason for the higher EL efficiency may be the insulating layer playing the role of a tunneling barrier for holes to the Al electrode. In all EL devices, the orange-red light was clearly visible in a dark room. Maximum peak wavelength of EL spectrum emitted at 640nm in accordance with photon energy 1.9eV
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The Organic Electroluminescence (OEL) device, that was consisted of ALq3(8-hydroxyquinoline aluminum) and TPD(N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine), has been used. We investigated characteristics of brightness and current density about OEL that was oxidated each layers. We used two samples that were fabricated each continuous and non-continuous method. Emission was observed above 10mA/
$\textrm{cm}^2$ and luminance was measured to be 1530cd/$\textrm{cm}^2$ at a current density of 100mA/$\textrm{cm}^2$ . A luminance of over 2600cd/$\textrm{cm}^2$ was also observed after the final fabrication process. -
In this study, we have investigated the light-emitting property of the EL device with the thickness ratio of the HTL/ETL, which was 500
$\AA$ :500$\AA$ , 400$\AA$ :600$\AA$ , 600$\AA$ :400$\AA$ . The ALq$_3$ was used for the ETL. We have studied the relation of voltage, contrase, efficiency for current density. Emission was observed above 10mA/$\textrm{cm}^2$ and luminance was measured to be 1030cd/$m^2$ at a current density of 100mA/$\textrm{cm}^2$ in 500$\AA$ /500$\AA$ sample. A luminance of over 2500cd/$m^2$ was also observed after the final fabrication process in 500$\AA$ /500$\AA$ sample -
Lee, Ho-Sik;Kim, Sang-Keol;Lee, Won-Jae;Park, Jong-Wook;Song, Min-Jong;Kim, Tae-Wan;Kang, Dou-Yol 174
We have synthesized the new blue electroluminescent material, Bis(3-N-ethylcarbazolyl)cyanoisophthalidene(BECCIP), and characterized its properties by UV/visible absorption, photoluminescent(PL) and electroluminecent(EL) spectrum. This material is well vacuum-deposited far thin film and has clear surfaced thin film property. The BECCIP shows blue PL and EL spectra at around at 485nm. -
In this paper, we studied efficiency improvement of linear ultrasonic motor using projection. The principle of ultrasonic motor is to use an elliptic motion generated at the side of the vibrator, and the elliptic motion of the ultrasonic motor was obtained by complex oscillation of L
$_1$ -B$_4$ mode. As the experimental results, the efficiency of linear ultrasonic motor without projection was 1.52[%] when applied voltage was 56[V] in resonance frequency 58.4[kHz]. The efficiency of linear ultrasonic motor using projection was 3.36[%] when applied voltage was 56[V] in resonance frequency 58.4[kHz]. The efficiency was improved by projection. -
Ultrasonic Motors of Wind-Mill type(diameter in 11.35mm, thickness in 2.8mm, and 1.44g weight) using Piezoelectric Ceramics have been developed. In recent study, Maximum torque in 100
$V_{max}$ , 105.8kHz was 7.2${\mu}$ N$.$ m, and bidirectional revolution using single-phase AC was presented. However, it is difficult to use because of small torque. Thus, in present study, new type of Wind -Mill Type Ultrasonic Motor of was designed as stator' structure was changed -
In this paper, a ring-type ultrasonic motor divided into 12 sectors was modeled by Atila program using finite element method(FEM). The stator consists of a piezoelectric ceramic poled alternately in opposite directions and elastic material. And the stator dimension was
$\Phi$ 40 (outer diameter),$\Phi$ 30(inner diameter), 0.5mm(ceramic thickness) and 3mm(elastic material thickness). As a simulation result, 6$\lambda$ displacement occurred at approximately 52kHz, and this resonance frequency is similar to calculated result 57kHz. The position of maximum displacement was at the edge of stator. -
The properties of piezoelectric and dielectric for 0.05Pb(Mn
$\_$ 0.4/W$\_$ 0.2/Nb$\_$ 0.4/)O$_3$ - 0.95PbZr$\_$ x/Ti$\_$ 1-x/O$_3$ compositions have been investigated. In the composition of 0.05Pb(Mn$\_$ 0.4/W$\_$ 0.2/Nb$\_$ 0.4/)O$_3$ - 0.95PbZr$\_$ 0.51/Ti$\_$ 0.49/O$_3$ , the values of k$\_$ p/ and$\varepsilon$ $\_$ 33/$\^$ T//$\varepsilon$ $\_$ 0/ are maximized, but Q$\_$ m/ was minimized (k$\_$ p/=56.5[%], Q$\_$ m/=1130, d$\_$ 33/=258[pC/N],$\varepsilon$ $\_$ 33/$\^$ T//$\varepsilon$ $\_$ 0/=1170). The grain size was suppressed and the uniformity of grain was improved at the 1100[˚C]. Also, we can see the dielectric constants variations between the before poling and after poling. This effect results from the effect(increase element of dielectric constants) between dipole switching and electrostriction inducing stress and dipole direction to the poling orientation(decrease element of dielectric constants). At x=0.51, we can find MPB(morphotropic phase boundary). -
Antimony doped tin oxyde thin films have been deposited by sol-gel method using non-alkoxide precursor SnCl
$_2$ $.$ 2H$_2$ O as host and SbC1$_3$ as dopant material. Using spin coating method, thin films of thickness up to 200nm have been uniformly deposited on Corning 1737F non-alkali glass substrates. Effect of Sb doping concentration and heat treatment on electrical and optical properties was investigated. Heat treatment was performed at the temperature from 350$^{\circ}C$ to 650$^{\circ}C$ in flowing O$_2$ . The resulting ATO films showed widely changing electrical resistivity and optical transmittance values in the visible spectrum depending on the composition and firing condition. -
마이크로파용 세라믹 유전체로 사용되는 MgTiO
$_3$ -CaTiO$_3$ 계 유전체에 Li을 첨가하여 이때 얻어지는 마이크로파 유전특성과 소결특성에 대하여 알아보았다. 94MgTiO$_3$ -6CaTiO$_3$ 으로 주조성을 고정시키고 여기에 Li$_2$ CO$_3$ 를 Li원자 기준으로 0 ~ 10 mol% 범위 안에서 첨가하여 1200~140$0^{\circ}C$ 의 온도에서 4시간 소결하였다. Li의 첨가량이 적을 때에는 유전체의 품질계수와 유전상수가 모두 감소하였으나 약 lmol% 이상 되면 다시 증가하였으며, 이후 첨가량이 과도해지면 다시 서서히 감소하는 경향을 볼 수 있었다. 1.0 ~ 3.0 mol%의 첨가량 범위 안에서 Li은 MgTiO$_3$ -CaTiO$_3$ 계 유전체의 품질계수를 증가시켜주는 역할을 하는 것으로 나타났다 1.5mol%의 Li을 첨가하고 1275$^{\circ}C$ 에서 4시간 소결한 시편에서 유전상수는($\varepsilon$ $_{r}$ ) 20.0, Qf는 78,000 그리고 공진주파수 온도계수($\tau$ $_{f}$ )는 -1.6ppm/$^{\circ}C$ 의 결과를 얻을 수 있었다.다. -
The application of the ultrasonic nozzle has been extended because it is possible atomization of liquid material. In this study, the characteristics of the ultrasonic nozzle and ceramic oscillator were investigated. The oscillator for the ultrasonic nozzle were made piezoelectric ceramic of Pb[(
$Sb_{1/2}$ $Nb_{1/2}$ )$_{0.035}$ -($Mn_{1/3}$ $Nb_{2/3}$ )$_{0.065}$ -($Zr_{0.49}$ $Ti_{0.51}$ )$_{0.90}$ ]$O_3$ . The electromechanical coupling factor($k_p$ ) and mechanical quality factor(Qm) showed the values of 0.555, 1, 214 respectively when the Zr/Ti ratio was 49/51. Moreover, this oscillator will have the temperature stability because it's curie temperature is 322[$^{\circ}C$ ]. The driving current of ultrasonic nozzle showed the value of 80[mA] when the driving time was lO[min.]. Also, The surface temperature of ceramic oscillator showed 80[$^{\circ}C$ ] at driving time lO[min.] We knew that the ultrasonic nozzle had stabile driving above 10[min.]. -
An ultrasonic linear motor was composed of a slider and a stator vibrator including piezoelectric material and elastic material. The ultrasonic linear motors mainly consist of an ultrasonic vibrator which generates elliptical oscillations. L
$_1$ -B$_4$ ultrasonic linear motor use longitudinal and bending multi-vibration. In order to low driving voltage and improve the life time of the ultrasonic oscillator, we used stacked piezoceramics. Stacked piezoceramics are adhered to aluminum elastic material. The finite element method was used to optimize dimension of ultrasonic vibrator and direction of vibratory displacement. As a result of estimating the characteristics of the ultrasonic linear motor, no-load velocity was 2.04[m/s] when applied voltage was 70[V$\sub$ rms/] in resonance frequency. -
Ba(Mg
$_{1}$ 3/$Nb_{2/3}$ )O$_3$ powders were synthesised from mechanochemically treated mixtures of Ba(OH)$_2$ . 8$H_2O$ , MgO and Nb$_2$ O$_{5}$ . Perovskite BMN powder of nanosized particles was successfully synthesized by using mechanochemical methods. Density and dielectric constant of samples with mechanochemical methods showed higher values than those of conventional processing.ng. -
ZnO varistors for distribution surge arrester (18kV, 5kA) were developed and tested microstructure and electrical characteristics. Microstructure of ZnO varistor was consisted of ZnO grain, spinel phase and Bi-rich phase. Average grain size of ZnO varistor was
$\mu\textrm{m}$ Reference voltage and lightning impulse residual voltage of ZnO varistor exhibited a good haracteristics above 5.5kV and below 11.56kV, respectively. Consequently, discharge capacity which is the most important characteristics of ZnO varistor for surge arrester exhibited excellent properties above 70kA at twice high-current impulse test. Moreover, variation rate of reference voltage and lightning impulse residual voltage showed below 5% and 2% after high-current impulse test, respectively. Leakage current and watt loss of ZnO varistor will not increase during accelerated aging test at stress condition, such as 3.213kV/$115^{\circ}C$ /1000h. -
The SrBi
$_2$ Ta$_2$ O$\_$ 9/(SBT) thin films are deposited on Pt-coated electrode(Pt/TiO$_2$ /SiO$_2$ /Si) using RF sputtering method. The SBT thin films deposited on substrate at 400-500[$^{\circ}C$ ]. SBT thin film deposited on Pt-coated electrodes have the cubic perovskite structure and polycrystalline state. With increasing annealing temperature from 600[$^{\circ}C$ ] to 850[$^{\circ}C$ ], flourite phase was crystallized to 650[。 and Bi-layered perovskite phase was crystallize ed above 700[$^{\circ}C$ ]. The maximum remnant polarization and the coercive electric field is 11.73[${\mu}$ C/$\textrm{cm}^2$ ], 85[kV/cm] respectively at annealing temperature of 750[$^{\circ}C$ ]. The fatigue characteristics of SBT thin films deposited on Pt/TiO$_2$ /SiO$_2$ /Si substrate did not change up to 10$\^$ 10/ switching cycles. -
The microwave dielectric properties of Ba(Mg
$_{1}$ 3/Ta$_{2}$ 3/)O$_3$ -xBa(Co$_{1}$ 3/Nb$_{2}$ 3/)O$_3$ [BMT-BCN] ceramics were investigated. The specimens were prepared by the conventional mixed oxide method. It was found that Ba(Mg$_{1}$ 3/Ta$_{2}$ 3/)O$_3$ and Ba(Co$_{1}$ 3/Nb$_{2}$ 3/)O$_3$ formed a solid solution with complex perovskite structure. Increasing the BCN content, dielectric constant was increased, but temperature coefficient of resonant frequency was decreased. In the range of x$\geq$ 0.4, dielectric constant was about 30. 0.55BMT-0.45BCN ceramics showed excellent microwave dielectric properties with$\varepsilon$ $_{r}$ =30.84, Q$\times$ f$_{0}$ =75,325[GHz] and$\tau$ $_{f}$ =-2.9015[ppm/$^{\circ}C$ ].X>]. -
Addition effects of metal oxide on the characteristics of infrared radiator of porous cordierite have been investigated. The porosity was increased with adding the graphite for 2MgO
$.$ 2A1$_2$ O$_3$ $.$ 5SiO$_2$ . The microstructure and the spectral emissivity were investigated as a function of metal oxide additives. The prosity and the emissivity were decreased with increasing amounts of CuO additives. The prosity and the emissivity were increased with increasing amounts of CoO, MnO$_2$ additives. The infrared radiator of cordierite system which spectral emissivity was 0.927 and 0.928 at from 5$\mu\textrm{m}$ to 20$\mu\textrm{m}$ wavelength as a 9wt% of CoO and MnO$_2$ additives. -
In this study, the temperature coefficient of resonant frequency(
$TCF_r$ ), dielectric and piezoelectric properties of$Pb_{1-x}Sr_x[(Sb_{1/2}Nb_{1/2})_{0.035}(Mn_{1/3}Nb_{2/3})_{0.065}(Zr_{0.49},Ti_{0.51})_{0.90}]O_3$ ceramics were investigated with the Sr substitution to Pb site. The dielectric constant was increased according to the increase of Sr substitution and electromechanical coupling factor($k_t$ ) also showed the highest values of 0.485 when the Sr substitution was 5 mol%. Moreover, the mechanical quality factor($Q_{mt}$ ) showed the highest value of 233 when the Sr substitution was 2 mol%. -
In this paper, the structural, dielectric and piezoelectric properties of the Pb[(S
$b_{1}$ 2/N$b_{1}$ 2/)$_{0.035}$ -$_Mn_{1}$ 3/N$b_{2}$ 3/)$_{0.065}$ -(Z$r_{0.49}$ ,$Ti_{0.51}$ )$_{0.90}$ ]$O_3$ ceramics were investigated with respect to the variation of the milling time. Grain size was decreased as the increase of milling time. As the milling time is increased, the particle size of the powder was decreased. Dielectric constant and electromechanical coupling factor (Qm)were slowly increased with the increase of milling time. The highest value of Qm was 1,497 at milling time 8 hour. Temperature coefficient of resonant frequency(TC$F_{r}$ ) was moved to positive side with the increase of milling time.e.e.e.e.e.e. -
In this paper, we manufactured Pb(
$Ni_{1/2}$ $W_{1/2}$ )$O_3$ -Pb($Mn_{1/3}$ $Nb_{2/3}$ )$O_3$ -Pb($Zr_3$ Ti)$O_3$ ceramics with variation of milling time and investigated its dielectric and piezoelectric properties. Density was increased with the increase of milling time because the sinterability of specimens were improved with the decrease of particle size. The highest value of electromechanical coupling factor was 0.518 at milling time 5hour. The highest values of mechanical quality factor and dielectric constant were 1566, 1590 at milling time 4hour, respectively. -
The electrical properties of ZPCCE (ZnO-Pr
$_{6}$ O$_{11}$ -CoO-Cr$_2$ O$_3$ -Er$_2$ O$_3$ ) based varistors were investigated with sintering temperature in range of 1335 to 135$0^{\circ}C$ for 1h. As the sintering temperature increases, the nonlinear exponent decreased, but was high beyond 40 except for 1.0 mol% Er$_2$ O$_3$ . Among all ZPCCE varistors, the varistor having the highest nonlinear exponent was obtained by sintering at 1335$^{\circ}C$ , containing 2.0 mol% Er$_2$ O$_3$ and then the nonlinear exponent was 78.05, and the varistors with 0.5 mol% Er$_2$ O$_3$ exhibited the lowest leakage current of 1.92$\mu$ A.A.A. -
Reactive radio frequency (RF)magnetron sputter has been used to deposit AlN thin film on a Si substrate. (002)Preferred orientation of AlN thin film has been obtained at low sputtering pressure and high
$\textrm{N}_2$ concentration. Also it has been shown that properties of AlN thin film are affected by presputtering time. As presputtering time increased aluminum and nitride concentration of AlN thin film decreased. But oxygen concentration and grain size increased. The good preferred orientation was shown with the short presputtering time. -
This paper was to measure the structure, electric characteristics of 0.05Pb(
$(Al_{0.5}Nb_{0.5})$ ) - 0.95Pb$(Zr_{0.52}Ti_{0.48})O_3$ ceramics dopped with Cr+Fe. The results of this paper were gotten such as follows; The dielectric constants were decreased with Cr+Fe. The dielectric loss was minimum value of 1.008[%], dopped with Cr+Fe O.9[wt%] at 1200[$^{\circ}C$ ], In case of sintering at 1150[$^{\circ}C$ ], electromechanical factodkp) was maximum value of kp 42.73[%], at Cr+Fe 0.9[wt%]. The mechanical quality factor(Qm) was maximum value at Cr+Fe 1.2 [wt%], Also, in case of dopped with Cr+Fe, it make a improvement in temperature coefficient of resonant frequency at 0.3[wt%], 1150[$^{\circ}C$ ]. -
In this study, the structural, dielectric and piezoelectric properties of Pb[(Sb
$\sub$ 1/2/Nb$\sub$ 1/2/)$\sub$ x/- (Ni$\sub$ 1/3/Nb$\sub$ 2/3/)$\sub$ 0.15-x/- (Zr,Ti)$\sub$ 0.85/]O$_3$ (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) ceramics is investigated as a function of Pb(Sb$\sub$ 1/2/Nb$\sub$ 1/2/)O$_3$ (abbreviated PSN) substitution. With the increase of PSN substitution, the crystal structure is transO$_3$ formed from the tetragonal phase to the rhombohedral phase and the grain size is decreased abruptly. The curie temperature is decreased with the PSN substitution. The dielectric constant is increased with the PSN substitution and maximum value of 2290 is obtained at 4mol% PSN. With the PSN substitution, the coercive field is increased and the remnant polarization is decreased. The Electromechanical coupling factor(k$\sub$ p/) Is showed the highest value of 0.622 at lmol% PSN and the mechanical quality factor(Q$\sub$ m/) is decreased abruptly with the PSN substitution. -
In this study, 3.1
$\times$ 3.7$\times$ 0.365$\textrm{mm}^2$ model of thickness-longitudinal vibration mode VHF ceramic resonator with (Pb,Ca)(Co,W,Ti)O$_3$ ceramics was simulated by ANSYS according to the electrode size. With the variations of electrode size of the model, fundamental and the third overtone dynamic ratio was investigated. At the ratio of electrode to model thickness(1/t) 2.5, third overtone dynamic ratio was largely increased. That model is suitable for 20 MHz resonator. -
Effects of excess Pb(50 mole %) on the crystallization properties of amorphous PZT thin films on the glass substrates by post-annealing in oxygen ambient were investigated to lower the crystallization temperature of the PZT thin films with a single perovskite phase. The PZT thin films(350nm) were prepared on Pt/Ti/corning glass(1737) substrates. The PZT thin films and bottom electrode were deposited by RF magnetron sputtering. Crystallization properties of PZT thin films were strongly dependent on RTA(Rapid Thermal Annealing) temperature. We were able to obtain a perovskite structure of PZT at 600
$^{\circ}C$ for 10min. After thermal treatments were done, electrical properties such as I-V, P-E, and fatigue were measured. -
This paper describes measurement of relative permittivity of illite found in young-dong area. A measurement of relative permittivity of illite used to cylindrical cavity resonators with moveable cap. A concentric dielectric-rod inserted cylindrical cavity resonator and an exact field representation of travelling wave mode are introduced for measurement of relative permittivity. The exact electromagnetic fields in cylindrical cavity with concentric dielectric rod is analysed. A relative permittivity of dielectric in cavity is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. We know that the field representation of travelling mode is exact. As a result, relative permittivity of dielectric materials were 7.820 at sample-1 and 7.894 at sample-2.
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Gas sensor materials capable of detecting hydrogen gases (H
$_2$ ) or nitrogen oxides (NO$\_$ x/, primarily NO and NO$_2$ ) with high sensitivity have attracted much interest in conjunction with the growing concern to the protection of global environments. Beside conventional sensor materials, such as semiconductors., conducting polymers and solid electrolytes, the potential of sensor materials with a new method for detecting hydrogen gases or nitrogen oxides gas has also been tested. The breakdown voltage of porous varistors shifted to a low electric field upon exposure to H$_2$ gas, whereas it shifted to a reverse direction in an atmosphere containing oxidizing gases such as O$_3$ and NO$_2$ in the temperature range of 300 to 600$^{\circ}C$ . Furthermore, it was found that the magnitude of the breakdown voltage shift, i. e. the magnitude of sensitivity, was well correlated with gas concentration, and that the H$_2$ sensitivity was improved by controlling the composition of the Bi$_2$ O$_3$ rich grain boundary phase. However, NO$\_$ x/ sensing properties of porous varistors have not been studies in detail. The objective of the present study is to investigate the effect of the composition of the Bi$_2$ O$_3$ rich grain boundary phase and other additive such as A1$_2$ O$_3$ on the hydrogen gases (H$_2$ ) sensing properties of porous ZnO based varistors. -
We were fabricated of NiCr thin film resistors(TFR) on A1
$_2$ O$_3$ (99.5%) substrates by dc magnetic sputtering system. The characteristics of electrical resistance (Sheet resistance & Temperature-Coefficient of the resistance-value:TCR) by annealing condition and reactive gas on the resistors were studied. -
The displacement current measurement has been employed to study the dielectric properties of Langmuir films. A method for determining the dielectric relaxation time
$\tau$ of floating monolayers on water surface is presented. The displacement current flowing across monolayers is analyzed using a rod-like molecular model. It's revealed that the dielectric relaxation time$\tau$ of monolayers in the isotropic polar orientational phase is determined using a liner relationship between the monolayers compression speed$\alpha$ and the molecular maximum area$A_{m}$ . The compression speed$\alpha$ was about 30, 40, 50mm/minmm/min -
In this paper, generation form of displacement current was compared and measured induce monolayers which 8A5H with Pure azobenzene. Light response of two monolayers which compared and measured though they are the same isomer. The experimental results are as following; In case of ultraviolet(
$\lambda_1$ ) and visible($\lambda_2$ ) irradiation on 8A5H induce monolayers depositioned on board the peak of current was detected about 10[fA]. but light irradiation on pure azobenzene any particular reaction for detailed. This is the reason of hydrophobicity construct in molecule structures its molecule dynamic behaviour in cis and trans was not due to activated. -
We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 20[mN/m]. LB layers of Arac. acid deposited by LB method were deposited onto y-type silicon wafer as x, y, z-type film. In processing of a device manufacture, we can see the process is good from the change of a surface pressure for organic thin films and transfer ratio of area per molecule. The structure of manufactured device is Au/arachidic acid/Al, the number of accumulated layers. Also, we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from 0 to +2[V].
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The crystallization behavior and dc Conductivities of CuO-P
$_2$ O$_{5}$ -Nb$_2$ O$_{5}$ -V$_2$ O$_{5}$ glasses prepared by quenching on the copper plate were investigated. The conductivities of the glasses were range from 10$^{-5}$ s.$cm^{-1}$ / at room temperature, but the conductivities of the glass-ceramics were 10$^{-3}$ s.$cm^{-1}$ / increased by 10$^2$ order. The crystalline product in the glass-ceramics was CuV$_2$ O$_{6}$ . The linear relationship between in($\sigma$ T) and T$^{-1}$ suggested that the electrical conduction in the present glass-ceramics would be due to a small polaron hopping mechanism. -
Vanadate glasses in the Li
$_2$ O-P$_2$ O$_{5}$ -V$_2$ O$_{5}$ system containing 10~20mo1% glass former, P$_2$ O$_{5}$ were prepared by melting the batch in pt. crucible followed by quenching on the copper plate. We found that Li$_2$ O-P$_2$ O$_{5}$ -V$_2$ O$_{5}$ g1ass-ceramics obtained from crystallization of glass showed significantly higher capacity and longer cycle life than Li$_2$ O-P$_2$ O$_{5}$ -V$_2$ O$_{5}$ g1ass. In the present paper, we describe electro-chemical properties during crystallization process and find the best crystallization condition of Li$_2$ O-P$_2$ O$_{5}$ -V$_2$ O$_{5}$ g1ass as cathod material. Li$_2$ O-P$_2$ O$_{5}$ -V$_2$ O$_{5}$ glass-ceramics shows superior rechargeable capacity of 220 mAh/g in the cycling between 2.0 and 3.9V. between 2.0 and 3.9V. -
RTD temperature sensor is a thermoresistor which uses the liner dependence of the resistance of the sensing material on the temperature, and has good stability and sensibility, so it can be used in highly precise temperature measurement. In this study RTD sensor was fabricated using Pt thin film. The Pt thin film was deposited on alumina using DC-Sputter, and annealed with various temperature. Through the experiments of XRD, AFM, 4-point probe, the surface structure of the thin film with annealing conditions and their effects on the electrical resistance were investigated. RTD with serpentine pattern was fabricated using Lift-off and resistance-temperature characteristics were studied.
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The effect of anisotropy field on the high frequency magnetic characteristics of FeTaN films was investigated. Those films show good magnetic properties : 4
$\pi$ Ms of 13KG, Hc of 0.6 Oe, effective permeability(${\mu}$ ') of 800 with a stable frequency response up to 800MHz. The films also show a large anisotropy field(Hk) over 21Oe. It result from the increased anisotropy of patterned FeTaN films. The combination of high saturation magnetization and relatively high Hk in these films is believed to the partly responsible for FeTaN for the excellent high-frequency behavior. -
The conductive polymers, polyaniline (PANI) emeraldine base and 3, 4-polyethylene dioxythiophene (PEDOT) were synthesized and coated on the PET film primer-dealt with acryl type to find out the electromagnetic shielding effectiveness. When conductive polymer such as PANI and PEDOT is used, if the thickness of coating increases then the electromagnetic shielding effectiveness increases, too, but the visible light transmittance decreases. For PANI, when its conductivity increased, its electromagnetic shielding effectiveness increased, too. For PANI, if the surface resistance is about 140
$\Omega$ /$\square$ , the shielding effectiveness is about 11 dB in the far field, and about 13 dB in the near field at 1 GHz. For PEDOT, when the surface resistance is about 200$\Omega$ /$\square$ , the shielding effectiveness is about 3 dB. -
Polyaniline Emeraldine Base (PANI EB) polymerized by chemical oxidative polymerization was doped with Camphorsulfonic Acid(CSA). Polyaniline-Camphorsulfonic Acid Emeraldine Salt(PANI-CSA ES) solutions were solved in organic solvents and sonificated at the room temperature for different solvents in PANI-CSA ES solution and sonification time. PANI-CSA ES solutions was coated on PET films using bar coater. 1-Step oxidatively-polymerized Polyaniline-Camphorsulfonic Acid Emeraldine Salt(PANI-CSA ES) was solved in m-cresol:chloroform 1:1 co-solvents and their solution was bar-coated on PET film. The surface resistivities of these coated films were measured, The surface resistivity of PANI-CSA ES solution in m-cresol:chloroform 1:1 co-solvent system was 5
${\times}$ 10$^2$ $\Omega$ /$\square$ . -
Urea is detected as an indicator of renal disease in the human body. For these reasons, many biosensors for urea have been developed based on the enzymatic reaction of urea hydrolysis catalyzed by urease. Potentiometric method is applied reversible reaction system. But urea hydrolysis reaction may not has a reversible reaction mechanism in electrode surface. Therefore we applied to voltammtricmethod to obtain a sensitivity curve. The sensitivity of sensors was 34
${\mu}$ A/decade. -
We fabricated the QCM with Langmuir-Blodgett(LB) film deposited at the different subphase pH and investigated the resonant frequency response by the injection of organic gas response. In the
$\pi$ -A isotherms, the monolayer on the air/water interface had different limiting area per molecule and showed more condensed status as increasing the subphase pH. When palmitic acid LB film was deposited on the QCM, the resonant frequency shift was proportional to the deposited layer and had more resonant frequency shift in the case of the higher pH range as expected. In the resonant frequency for the injection of organic gas, it has been improved in the case of LB film fabricated at the lower subphase pH range and dependant upon the molecular weight of organic gas. -
We attempted to fabricate polyurethane derivatives (PU-CN, PU-DCM) LB films by using LB method. Also, we investigated the monolayer behavior at the air-water interface by surface pressure-area (
$\pi$ -A) isotherms. And, the surface morphologies and the physicochemical properties of LB films were investigated by atomic force microscopy (AFM) and UV-vis spectroscopy, respectively. Also, the electrical properties of polyurethane derivatives LB films were investigated by using the conductivity and the dielectric constant. In the AFM images, we conclude that surface morphology of PU-DCM LB films is smooth and homogeneous and has optimal hydrophobicity and good stability, whereas PU-CN LB films give rougher surfaces with more excess material. In the I-V characteristics, the conductivity is different as to the polyurethane derivatives, it is considered that this phenomena could be described by the difference of lumophore pendant which was adhered at PU main chain. -
ZnO(Zinc Oxide) thin films were deposited on glass substrate by Facing Targets Sputtering. Facing Targets Sputtering system can deposit thin films in plasma-free situation and change the sputtering conditions in wide range. The characteristics of ZnO thin films deposited at variation of sputtering conditions films thickness, power and substrate temperature were evaluated by XRD(x-ray diffractometer),
${\alpha}$ -step (Tencor). The excellently c-axis oriented ZnO thin films were obtained at sputter pressure ImTorr, power 150W, substrate temperature 200$^{\circ}C$ . In these conditions, the rocking curve of ZnO thin films deposited on glass was 3.3$^{\circ}$ . -
The effect of the constituent elements and their composition of the seed layer on the properties of the evaporated Zn thin films was investigated. It was carried out by the analysis of the preferred orientation and the grain size, and the corrosion characteristics. Seed layers were prepared by evaporation of Al and AlCu respectively, and here the Cu content as additives of the source materials of seed layers were designed 5 a/o to 20 a/o. The values of full width at half maximum (FWHM) of the (002) x-ray diffraction peaks of Zn decreased by increasing the amount of the additives on Al seed layer, as a results, the grain sizes also decreased. In order to characteristics of Zn thin films evaporated on the various seed layers, electrical resistivity changes with a function of time at the temperature of 40
$^{\circ}C$ and the relative humidity of 80%, as a result, the relative resistivity changes were increased by decreasing the grain size and the FWHM values of (002) peaks of Zn. -
The purpose of this study is to research and develop conducting polymer(CP) composite electrode for supercapacitor. Supercapacitor cell of CP composite electrode with 1M LiClO
$_4$ / PC bring out good capacitor performance below 4V. The radius of semicircle of CP composite cell with PAn composite electrode adding 30wt% acetylene black was absolutely small. The total resistance of supercapacitor cell mainly depended on internal resistance of the electrode. The discharge capacitance of supercapacitor cell with PAn composite electrode adding 30wt% acetylene black in 1st and 50th cycles was 27F/g and 31F/g at current density of 1mA/$\textrm{cm}^2$ . Supercapacitor cell with PAn composite electrode adding 30wt% acetylene black performed a good cycliability. -
Carbon is an attractive candidate for use in eletrochemical supercapacitors that depend on charge storage in the electrode/electrolyte international double layer. Property of an electrical double layer capacitor depend both on the technique used to prepare the electrode and on the current collector structure. The study is to research that V
$_2$ O$_{5}$ -flyash-AC composite electrode for supercapacitor. The discharge capacitance of V$_2$ O$_{5}$ -flyash-AC(70wt%) in 1st and 50th cycle was 18.6F/g and 15.13F/g at current density of 0.5mA/cm$^2$ . The discharge process of V$_2$ O$_{5}$ -flyash (3 : 97)-AC composite electrode is larger than that others.thers. -
Polypyrrole(PPy) nanotubules were formed within template pores by chemical synthesis using
$FeCl_3$ as an oxidant. The oxidation peak of PPy nanotubules in the cyclic voltammogram was observed at about 2.8V and 3.3V vs.$Li/Li^+$ , while in the case of PPy film, that was observed at about 3.0V. It suggests that the electron hopping on the main chain of PPy nanotubules was improved. When the PPy nanotubules was used to a cathode of lithium secondary battery, we obtained discharge capacity as much as 27 mAh/g, and initial coulomb efficiency by 90%. We expect that the capacity can be improved by further study. -
This paper presents the characteristics of low consumption, high-response time hot-film type micro-flowsensors with SOI(Si-on-insulator) and trench structures. Output voltages increased due to increase of heat-loss from sensor to external. Compared with no-trench on the SOI structure, the micro-flowsensors with trench structures have properties of high output voltage and low consume power. Output voltage of micro-flowsensors with SOI and trench structures was 250 mV at
$N_2$ flow rate of 2000 sccm/min, heating power of 0.3 W. The response time was about 85 msec when input flow was step-input. -
The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li polymer battery. The temperature dependence of conductivity, impedance spectroscopy and electrochemical properties of PMMA/PVDF electrolytes as a function of a mixed ratio were reported for PMMA/PVDF based polymer electrolyte films, which were prepared by thermal gellification method of preweighed PMMA/PVDF, plasticizer and Li salt. The ion conductivity of PMMA/PVDF electrolytes was 10
$\^$ -3/S/cm, which may be applicable to a constituent of lithium secondary battery. 5PMMA20PVDFLiC1O$_4$ PC$\sub$ 8/EC$\sub$ 8/ electrolyte remains stable up to 5V vs. Li/Li$\^$ +/. Steady state current method and AC impedance were used for the determination of transference numbers in PMMA/PVDF electrolyte film. The transference number of 5PMMA20PVDFLiC1O$_4$ PC$\sub$ 8/EC$\sub$ 8/ electrolyte is 0.55. -
AC impedance of LiM
$n_2$ $O_4$ and LiM$g_{0.1}$ M$n_{1.9}$ $O_4$ samples have been studied at various temperature with charge-discharge test. AC impedance of LiM$n_2$ $O_4$ measured at -2$0^{\circ}C$ , room temperature and 5$0^{\circ}C$ revealed that initial impedance before charge-discharge test was gradually decreased and become small by becoming law temperature. It indicates that the Li ion diffusion and the transfer resistance of the cathode are related to the temperature of cycling. Impedance at high temperature was suddenly increased because Mn dissolution and decomposition of electrolyte had been increased during cycling, compared to impedance at low temperature. Therefore, charge-discharge capacity was suddenly decreased at high but was slowly at low. In LiM$g_{0.1}$ M$n_{1.9}$ $O_4$ , impedance and capacity were stability at room temperature than there at 5$0^{\circ}C$ , too. Initial impedance at 5$0^{\circ}C$ before charge-discharge test was small and impedance was suddenly increased during cycling than that at room temperature.ure.ure. -
Magnetoresistance changes of NiFe thin films were investigated as a function of deposition temperature. DC magnetron sputtering was employed to fabricate Ta/NiFe(t)/Ta thin films on Si(001) substrates with in-situ field or with no-field. The thickness(t) of NiFe films was a range of 4 to 15nm. Substrate temperature was a range of 30 to 400
$^{\circ}C$ . MR measurement was carried out as a function of angle$\theta$ , between external field and current direction. MR ratio increased with increasing substrate temperature, also, max. MR ratio was observed in samples deposited at 300$^{\circ}C$ . With increasing upto 400$^{\circ}C$ , MR ratio was rapidly decreased in the case of thinner NiFe films. In non-field deposited NiFe films, both angle$\theta$ =0, 90。, there was no significant change in MR curves. However, MR curves of in-situ field deposited NiFe films were different in both angles$\theta$ =0 and 90。 -
The purpose of this study is to research and develop graphene composite for lithium polymer battery. VO(graphene) composite is one of the promising material as a electrode active material for lithium polymer battery(LPB). We investigated AC impedance response and charge/discharge cycling of VO(graphene)/SPE/Li cells. The first discharge capacity of VO(graphene) cathode with 50wt.% V
$_2$ O$\sub$ 5/ was 150mAh/g, while that of VO(graphene) cathode with 85wt.% V$_2$ O$\sub$ 5/ was 248mAh/g. The Ah efficiency was above 98% after the 2nd cycle. The discharge capacity of VO(graphene) anode with 3wt.% V$_2$ O$\sub$ 5/ was 718 and 266mAh/g at cycle 1 and 10 at room temperature, respectively. The VO(graphene) anode with 3wt.% V$_2$ O$\sub$ 5/ in PVDF-PAN-PC-EC-LiC1O$_4$ electrolyte showed good capacity with cycling. -
In this study, SrBi
$_2$ Ta$_2$ $O_{9}$ (SBT) thin films were etched at different Cl$_2$ gas mixing ratio in Cl$_2$ /Ar. The maximum etch rate of SBT was 883$\AA$ /min in Cl$_2$ (20%)/Ar(80%). The result indicates that physical sputtering of charged particles is dominant to chemical reaction in etching SBT thin films. To evaluate the changes of morphology and crystallinity on the near surface of etched SBT, atomic force microscopy (AFM) and x-ray diffraction (XRD) were used. The rms values of etched samples in Ar only or Cl$_2$ only plasma were higher than that of as-deposited, Cl$_2$ /Ar Plasma. The SBT (105) crystalinity of the etched samples decreased in Af only or Cla only plasma, but maintain constant in ClyAr plasma. This can be illustrated by a decrease of Bi content or nonvolatile etching products (Sr-Cl and Ta-Cl), resulting in the changes of stoichiometry on the etched surface of the SBT thin films. The decrease of Bi content and nonvolatile etch products were revealed by x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS).). -
In this study, thin films of 70/30 and 80/20 mol% P(VDF-TrFE) copolymers were fabricated by physical vapor deposition method. In order to determine the optimum deposition condition, the copolymer thin films were fabricated in the heating temperature of 260
$^{\circ}C$ , 280$^{\circ}C$ , and 300$^{\circ}C$ . The deposition rate was measured in a real time by thickness monitor. The surface image of prepared thin films was analyzed by using AFM. From the results of TG-DTA,70/30 and 80/20 mol% P(VDF-TrFE) copolymers were observed the Curie transition point below the melting point. As the results of AFM and FT-IR analysis, we determined that the optimum deposition temperature was 300$^{\circ}C$ . -
The electrochemical properties of LiM
$n_2$ $O_4$ as a cathode and an anode for the lithium secondary battery were evaluated. When LiM$n_2$ $O_4$ material was used as the cathode with the current collector of aluminum, the 1st specific capacity and the 1st Ah efficiency in LiM$n_2$ $O_4$ /lithium cell were 123 mAh/g and 91.7%, respectively The anodic properties of LiM$n_2$ $O_4$ material was also evaluated in the LiM$n_2$ $O_4$ /1ithium cell with the current collector of copper. It showed that the LiM$n_2$ $O_4$ was useful as the anode for the lithium secondary battery. During the 1st discharge, a potential plateau was observed at the potential of 0.3$V_{Li}$ Li+/. The 1st specific charge capacity and the 1st specific discharge capacity were 790 mAh/s and 362 mAh/g, respectively. Therefore, the 1st Ah efficiency was 46%. The discharge capacity was gradually faded with the charge-discharge cycling to about 50th cycles. Thereafter, the discharge capacity was stabilized to about 110 mAh/g. -
This paper investigated that resonant frequencies of microstrip patch antenna were tunable when piezoelectric materials were used as the antenna substrates. The resonant frequencies of the microstrip antenna using the piezoelectric substrate, like PZT, LiNbO
$_3$ were able to be controlled by applied DC voltage. The frequency variation of the air gap antenna was 29MHz when the voltage variation was 14[kV/cm], and the frequency variation of microstrip patch antenna made of LiNbO$_3$ substrate was 29MHz when voltage variation was 6[kV/cm]. -
The characteristics of Xe discharge lamp(Mercuryless lamp) are described in this paper. In this paper, FFL is operated by sine wave and pulsed source. We apply V-Q Lissajous' figure for the discharge measurements of FFL which has the electrodes covered with dielectric. When FFL is operated by sine wave source, the characteristics are similar to DBD(Dielectric Barrier Discharge) and SD(Silent Discharge). And we compared the characteristics of FFL which is operated with sine wave and pulsed discharge by using V-Q Lissajous' figure method. When FFL is operated with pulsed, the discharge current flows after the applied voltage is risen. As the duty ratio increases the electric field becomes strong and much more xenon ions are produced. And the number of metastable xenon atoms seem to increase, therefore, the phosphor radiation after the cut off of voltage increases compared with the first peak of radiation. Consequently, the 172㎚ radiation becomes strong as the duty ratio increases.
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Fuse mounted elbow connector used for pad mounted transformer was designed and investigated. Requirements of electrical ratings such as partial discharge, ac withstand voltage and impulse voltage and material properties were proposed in accordance with IEEE 386 and pre-standard (PS) 147-219∼229 of KEPCO. The connector can be jointed with pad mounted transformer and current limiting fuse which is installed inside of the connector easily replaced with new one in the case of breakdown of the fuse. Electric field analysis was also introduced in other to verify the reliability of the design.
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The life of transformer is significantly dependent on the thermal behavior in windings. To analyse winding temperature rise, many transformer designer have calculated temperature distribution and hot spot point by finite element method(FEM). Recently, numerical analyses of transformer are studied for optimum design, that is electric field analysis, magnetic field, potential vibration, thermal distribution and thermal stress. Therefore design time and design cost are decreased by numerical analysis. In this paper, the temperature distribution and thermal stress analysis of 50kVA pole cast resin transformer for power distribution are investigated by FEM program. The temperature change according to load rates of transformer also have been investigated. We have carried out temperature rise test and test results are compared with simulation data.
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EPDM/silicone blend was prepared with polyorganosiloxane compatibilizer for out-door polymer insulation used to shed. Each blend had various weight ratios, 100/0, 90/10, 70/30, 50/50, 30/70, 10/90, and 0/100 as EPDM to silicone, and electrical and tracking characteristics were studied with the method of IEC 60587. And also, tracking properties and contact angle related to UV-weathering period were studied to understand the degree of degradation of blend after 1000 h UV-weathering.
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In this study mechanical and environment ability of FRP pole for a distribution line about high strength and good insulation properties. The basic filament winding process creates a helical winding pattern. In mechanical analysis of splice with mechanical fastened joint it is important to evaluate a critical load of faster having maximum stress. It is also present a result of several examples to compare this with analytical one. On repair design this finite element method will be used as basis. The influence of environmental factors, such as elevated temperatures, high humidity, and corrosive fluids, and ultraviolet(UV) rays, upon the performance of polymeric matrix composite is of concern in many applications.
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Recently polymer insulators are being used for outdoor high voltage applications. Polymer insulators for transmission and distribution line have significant advantages over porcelain and glass insulators, especially for ultra-high voltage(UHV) transmission lines. Their advantages are light weight, vandalism resistance and hydrophobicity. In this paper, polymer line post insulator has been designed and investigated electric field distribution by FEM. Designed LP insulators have been tested as insulator performance test, such as power frequency voltage test, lightning impulse voltage test, artificial pollution test and flexural load test.
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The FRP pole had great advantages over other material poles. Light weight, easy installing and transporting were good characteristics. The material's superior properties represented the good durability for sea weather and air pollution, good insulation for electric, and changeable colors. In those properties, usages were like a area affected by sea, downtown, the area among the mountains and a special area for the outstanding views. It was studied that pole manufacturing method, structure analysis of pole by FEM in this study. Filament winding method was selected for a new pole manufacturing method. It produced the tapered poles and mechanically strong properties.
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We designed and fabricated VCO using inductive reactance variation at 2GHz. A varactor diode is one of the main devices in VCO, which varies capacitance depending on reverse voltage. In this paper, a varactor diode is not used as a variable capacitive reactance device but as an inductive device. The circuit design and simulation have been carried out using HP-MDS. The fabricated VCO is measured using the HP 8532B spectrum analyzer and the HP 4352B VCO/PLL analyzer. The experimental result shows the phase noise -110dBc/Hz at a 100kHz offset frequency, the control voltage sensitivity of 23MHz/V and a -3.5dBm output power with a D.C. current consumption of 5.9mA. The simulation and measurements show exact agreement except with regard to the oscillation frequency. The measured oscillation frequency is lower than the simulation result because there is some parasitic inductance in the PCB layout.
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A high performance EEG signal measurement system is fabricated. It consists of high precision pre-amplifier and auto identification bandwidth unit. High precision pre-amplifier is composed of signal generator, signal amplifier with a impedance converter, body driver and isolation amplifier. The pre-amplifier is designed for low noise characteristics, high CMRR, high input impedance, high IMRR and safety, Auto identification bandwidth unit is composed of AD-converter and PIC micro-controller for real time processing EEG signal. The performance of EEG signal measurement system has been shown the classified bandwidth through the clinical demonstrations.
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In this study, the physical properties of the acoustic element and case with metal-piezoelectric ceramics were analyzed. The dielectric and piezoelectric properties of 0.5 wt% MnO
$_2$ and NiO doped 0.1Pb(Mg$_{1}$ 3/Nb$_{2}$ 3/)O$_3$ -0.45PbTiO$_3$ -0.45PbZrO$_3$ ceramics were investigated aiming at acoustic transducer applications. The vibration characteristics for the laminated circular plate was analyzed for the various thickness and diameter of the piezoceramic layer and metal layer. Also, the acoustic characteristics for the geometrical form of case have been investigated. The design and fabrication method worked in this paper can be utilized in development of actuator and acoustic device. -
태양전지는 빛에너지를 전기에너지로 변환시켜주는 에너지변환 소자이다. 본 논문에서는 이 태양전지를 수신기의 전원 겸 안테나로써 사용하고자 한다. 태양전지를 수신기의 안테나로 사용하기 위해서는 태양전지가 받아 들이는 빛에너지에 음성신호를 인가해주어야 한다. 실험에서는 일정하지 않은 음성신호대신 Function Generator를 이용하여 신호를 넣어주고 이 신호를 LM741과 KA2904 내의 OP-amp를 통하여 증폭시킨 후 발광 다이오드(LED)에 인가시켜 주었다. LED의 광신호를 Solar-Cell이 받아들여, 직류전압은 전원으로 사용되고 교류신호는 음성신호로 사용된다. 본 실험은 빛을 이용한 무선 송·수신기의 기초적인 단계에 불과하나 고도의 기술이 필요하지 않으므로 그 파생효과와 발전 방향은 무궁무진하다고 할 수 있다.
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We have examined the impedance characteristics and the rate characteristics of LPB. As results, the impedance of LPB decreased with increased pressing rate of electrodes, adding amounts of PVdF and VGCF. And the rate characteristics of LPB increased with the a increase of pressure-rate, PVdF and VGCF contents. The rate characteristics of LPB was improved by pressing of electrode and adding of VGCF content. And specific capacity of anode was increased with adding amounts of PVdF. Higher pressing rate of electrodes, higher adding amounts of PVdF and VGCF was necessitated good rate characteristics for lithium polymer battery.
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본 논문에서는 영동산 일라이트가 갖는 기능성을 이용하여 정수기용 필터로써의 가능성을 검토한다. 대장균 실험을 통하여 항균성을 평가하였고, 여러 가지 중금속(Zn, Pb, Cu, Cd, Fe
$^{2+}$ )의 흡착능력을 평가하였다 정수기 필터재료로 사용하기 위한 성형조건을 실험하였고, 물 필터하우징에 성형된 illite ceramic을 충진하여 물을 정수 처리하여 버섯 재배에 적용하였다. 결과적으로 항균성은 white-yellow-red 순이었고 중금속흡착능력은 원소에 따라서 yellow가 white보다 크게 나타났고, 이에 착안하여 버섯재배에 적용한 결과 수율 향상에 크게 기여하는 것으로 나타났다. 본 논문에서 illite ceramic이 필터재료로서의 가능성을 나타내고 이를 개발, 보고 하고자 한다. -
본 논문의 정수기는 영동산 일라이트를 필터의 주된 재료로 사용하였다. 구조는 여과필터를 교체하여 사용할 수 있도록 된 정수기의 필터 케이스 및 여과 방법에 관한 것으로써, 보다 상세하게는 필터 케이스가 분리, 결합이 간편한 본체와 마개로 구성되어 있다. 이 본체는 1차 여과부와 2차 여과부로 분리되어 물이 1차 여과부의 상부를 통해 인입되어 2차 여과부의 상부로 연결되도록 되어 있어 동일한 크기 내에서 여과구간이 2배로 길어져 여과 효율이 우수한 동시에 물인입구와 물배출구가 동일한 방향에 위치하여 다수 개의 필터 케이스를 연결할 때 필터 케이스의 간격을 좁힐 수 있어 필터 케이스의 설치면적이 좁다. 본체와 마개의 체결방식은 볼트 체결방식으로 되어 있으며, 마개는 플라스틱 재질이어서 본체에 마개를 단단히 체결하면 누수가 방지되도록 되어있다. 즉, 정수기의 필터하우징 성능과 영동산 일라이트가 가지고 있는 기능성을 이용한 필터를 사용함으로써 정수기에서 요구되어지는 정수능력을 가진 정수기를 개발 보고한다.
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본 논문은 냉동상품용 자판기를 구현하는데 가장 핵심적인 상품인출기구에 관한 것으로 자판기의 냉동고에 저장된 상품을 외부로 인출할 때 냉기의 유출을 최소화하여 전력의 효율을 높여 전기에너지를 절감할 수 있도록하고. 냉동고 내부의 이송기구가 결빙에 의한 고장이 발생되지 않도록 이송기구를 구현하는 것이다. 기존 자판기는 상품을 냉동고에서 외부로 인출하려면 여러 기계, 기구 장치를 이용하여 어렵게 이송하여야 하고, 상품을 이동시키는 모터축이나 체인이 저온으로 인하여 결빙되어 작동불능 상태가 되게 된다. 이러한 고장은 자판기가 자판기 고유의 동작을 할 수 없을 뿐 아니라 소비자들에게 불편함을 주게 되는데 고장을 방지하여 신뢰성을 높였다. 그리고 상품을 외부로 인출시 저온 냉장고는 많은 냉기를 유출하게 되어 냉동 자판기로서의 활용을 무색하게 할 뿐 아니라, 다시 저온으로 유지하는데 많은 전력을 소모하게 된다. 이러한 점을 보완하여, 에너지 절약 및 보다 신뢰성 높은 냉동 식품용 자판기를 구현하였다.
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In this study, the interfacial dielectric breakdown phenomenon of interface between Epoxy and Rubber was discussed, which affects the stability of insulation system of power delivery devices. The breakdown strength of specimens are observed by applying high AC voltage at the room temperature. The breakdown times under the constant voltage below the breakdown voltage were gained. As constant voltage is applied, the breakdown time is proportion to the breakdown strength. The life exponent n is gained by inverse power law and the long time breakdown life time can be evaluated.
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In this paper, dielectric properties of XLPE sheets of 22kV cable with semiconducting and water were investigated. The breakdown strength of XLPE under rod/needle electrode were measured at without oil. It is found that the dielectric properties such tan
$\delta$ of XLPE sheet dependence on semiconducting and water layer and are decreased much lower increase with temperature. The breakdown strength and the electrode effect are obtained as a function of thickness, and a equation for the sheet thickness dependent breakdown strength is also discussion. -
The terminal and core(wire conductor) in a Harness processing is connected by putting them in a applicator by virtue of a manual operation. A normal or abnormal condition of crimping connections is nearly determined by a skilled worker. In general, a skilled worker operates a press motor with a foot switch by pressing on foot and puts a wire conductor into a press with one hand. By doing so, sufficient efficiency is not obtained by a worker. In this paper, a basic study has done to make improve an efficiency by finding the normal arrangement out as to whether a terminal and wire conductor in Harness are placed on the right position or not with a quadrant plane photo position sensor.
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Normal zone propagation(NZP) characteristics were investigated on Ag sheathed Bi-2223 tape and cylindrical stacked conductor. Normal zone propagation(N2P) experiments with tape were conducted with refrigerator in temperature from 45 K to 77 K, 0 T. Cylindrical stacked conductor was molding with epoxy and experiments were conducted with adiabatic condition in
$LN_2$ . NZP velocities of tape with two condition of DC and AC were almost same at each temperature. NZP velocities of cylindrical stacked conductor were 1.9-2.4 cdsec in$LN_2$ . Numerical analysis was carried out by a one-dimensional heat balance equation. As a result, simulated results of NZP velocity with Bi-2223 tape were similar to experimental results in DC. -
Superconducting power cable is one of the most promising energy application of high-T
$_{c}$ superconductors (HTS). A prototype HTS cable have been constructed multi-layer cable using Bi-2223 tape and tested. The AC transport losses under self field were investigated at 77K on the 19 filamentary tape and multi-layer HTS cables. And we carried out numerical analysis using bean model. The result shows that the total transport current of HTS cable in L$N_2$ was 475[A], and transport current passed through almost the outer layer (2-layer). Also, AC transport losses in outer layer of HTS cable was proportion to I$^2$ and higher than losses of inner layer. In case of Ip=Ic, calculated numerical loss density was concentrated on the edge of tape and most of loss density in cable was distributed outer layer more than inner layer. As magnetic distribution was concentrated on outer layer.r. -
A new method for the fabrication of poly-Si films is reported using by alternating magnetic flux crystallization (AMFC) of LPCVD a-Si films. In this work we have studied the crystallization of LPCVD a-Si films by alternating magnetic flux. A-Si films were 1200
$\AA$ -thick deposited at 48$0^{\circ}C$ at a total pressure of 0.25Torr using Si$_2$ H$_{6}$ /H$_2$ . After this step, these a-Si films were thermally annealed by Alternating Magnetic Flux at 43$0^{\circ}C$ for 1hours. The annealed films were characterized using X-ray diffraction (XRD), Raman Spectra, Atomic Force Microscopy(AFM). Both alternating magnetic flux crystallization and solid phase crystallization were investigated to compare enhanced crystallization a-Si. We have found that the low temperature crystallization method at 43$0^{\circ}C$ by alternating magnetic flux.x. -
According to the development of the semiconductor micro device technology, IC chip trends the high integrated, low power tendency. Nowadays, it can be showed the tendency of single chip in system level. But in the system level, IC operates by multi power supply voltages. So, semiconductor process is necessary for these multi power operation. Therefore, in this paper, dual gate high voltage device that operate by multi power supply of 5V and 20V fabricated in the 0.5
${\mu}{\textrm}{m}$ CMOS process technology and its electrical characteristics were analyzed. The result showed that the characteristics of the 5V device almost met with the SPICE simulation, the SPICE parameters are the same as the single 5V device process. And the characteristics of 20V device showed that gate length 3um device was available without degradation. Its current was 520uA/um, 350uA/um for NMOS, PMOS and the breakdown voltages were 25V, 28V. -
This paper present the result of the investigation, electric properties of outdoor insulators with the difference of contaminated condition. In general, the humidity and the amount of soluble salts such as NaCl, MgCl
$_2$ are the most dominant factor. A mini-fog chamber with transparent acryl and the standard contamination solution with kaoline was used. The kaoline was applied with sprayer to get the specific ESDD and NSDD value, then the specimen was dried and installed horizontally. And to measure the leakage current and the ambient condition, such as relative humidity and temperature, a DAS system was developed with LabView. From the result, we could know the influence of contaminated condition. Contaminated area and pattern has a close relationship with the electrical properties of outdoor insulator. -
P-type (100) Si wafer patterned with 1000
$\AA$ SiO$_2$ island was used as substrate and the Si films were deposited under low pressure using Si$_2$ H$_{6}$ -H$_2$ gas mixture where the total gas flow rate and deposition pressure were 16.6sccm and 3.5mtorr, respectively. In this condition, we selectively obtained high-quality epitaxial Si layer of the 350~1050$\AA$ thickness. In order to extend the incubation period, we kept high pressure H$_2$ environment without Si$_2$ H$_{6}$ gas for few minutes after first incubation period and then we conformed the existence of second incubation period.iod. -
In this study, mesh-type PECVD system was suggested to minimize the hydrogen concentration. The main structural difference between the triode system and a conventional system is that a mesh was attached to the substrate holding electrode. We investigated several conditions to compare with conventional PECVD. The main effect of mesh was to minimize the substrate damage by ion bombardment and to enhance the surface reaction to induce hydrogen desorption. It was also found that hydrogen concentration decreased but deposition rate increased as increasing applied dias. Applied DC bias enhanced sputtering process. Intense ion bombardment causes the weakly bonded hydrogen or hydrogen-containing species to leave the growing film and increased adatom mobility. Furthermore, addition of hydrogen gas enhance the surface diffusion of adatom. The structural properties of poly-Si films were analyzed by scanning electron microscopy(SEM).
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Polyimide is a well-known organic dielectric material, which has not only high chemical and thermal stability but also good electrical insulating and mechanical properties. In this research, the electrical properties of PI LB films were investigated at room temperature. At low electric field, ohmic conduction(I∝V) was observed and the calculated electrical conductivity was about 9.7
$\times$ 10$^{-15}$ S/cm. At high electric field, conduction(I∝V$^2$ ) was observed and the conduction mechanism was explained by space charge limited region effect. The dielectric constant of LB film was about 7.5. -
This study is for assessing a reliability of diagnostic device through comparing diagnostic results to ACDB strength. The dielectric diagnosis using IRC (isothermal relaxation current) measurement was carried on service-aged cables. From this study, there was little correlation between dielectric diagnosis and ACBD strength in long distance cables. But the correlation between them showed in short distance below 200 m. Therefore, it is desirable to diagnose the URD cables in short distance.
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Bi-2223/Ag superconducting wires have been mainly prepared by a powder-in-tube method. The drawing and the rolling are main processes to increase the core density and wire length. In the fabrication of long wire, especially, the drawing should be precisely controlled to assure the filament homogeneity. In this paper, the influences of drawing die angle, bearing length and reduction ratio on the sausaging and the critical current density of the wire are investigated. Single cored and multi-filamentary wires are fabricated by PIT method with different conditions. The core densities and sausaging in the wires are investigated and are discussed regarding their relationship to the I
$_{c}$ . It was made clear that the geometry of drawing die is sensitively dependent on the sausaging. The improvement of I$_{c}$ was achieved by reducing the die angle and high core density.ity. -
In order to develop an ultra-thin CoCr perpendicular magnetic recording layer, we prepared CoCrTa/Ti double layer for perpendicular magnetic recording media by new facing targets sputtering system, Crystallgraphics and magnetic characteristics of CoCrTa on underlayer substrate temperature have been investigated. Crystallgraphic and magnetic characteristic of thin films were evaluated by X-ray diffractometry(XRD), vibrating sample magnetometer(VSM) and atomic force microscopy(AFM). The coercivity and anisotropy field was increased by increasing under layer substrate temperature, c-axis orientation of CoCrTa magnetic recording layer was improved 8
$^{\circ}$ to 5.6$^{\circ}$ when under layer substrate temperature was 250[$^{\circ}C$ ]. Also, through annealing effect for CoCrTa/Ti double layer, it was certain that crystallgraphics and magnetic characteristics was improved. -
In order to investigate the effect of Ge addition to the Cu Matrix on the microstructure and the critical current density, four kinds of internal tin processed Nb
$_3$ Sn strands with pure Cu and Cu 0.2, 0.4, 0.6 wt% Ge alloy were drawn to 0.8 mm diameter. The microstructure and critical current of internal tin processed Nb$_3$ Sn wires that were heat treated at temperatures ranging from 68$0^{\circ}C$ to 74$0^{\circ}C$ for 240 h were investigated. The Ge addition to the matrix did not make workability worse. A Ge rich layer in the Cu-Ge matrix suppressed the growth of the Nb$_3$ Sn layer and promoted grain coarsening. The greater the Ge content in the matrix, the lower the net Jc result after Nb$_3$ Sn reaction heat treatment. There was no significant variation in Jc observed with heat treatment temperature ranging from 68$0^{\circ}C$ to 74$0^{\circ}C$ . -
BiPbSrCaCuO 계 초전도체에서 관측되는 자기부양효과에 대하여 연구를 수행하였다. BiPbSrCaCuO 계 초전도체에 산화은을 첨가한 시료와 첨가하지 않은 시료의 자기적 특성을 측정하여 자기부양효과의 메카니즘에 대하여 고찰하였다. toroidal자석에서 관측되는 자기부양 효과는 자석의 중심부분에서만 발생하며, 자석의 ring 부분에서는 관측되지 않았다. 이 결과는 본 연구의 자기 부양효과의 발생에는 자석의 형상 및 자속의 분포 형태와 밀접한 관련이 있음을 의미한다.
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YBCO superconducting thick films were prepared on Ag wire by electrophoresis in acetone and ethanol with chemically modified suspension. The addition of organic compounds, such as PEG, EG into suspension solution for improving critical current density was investigated. Surface state, deposition condition, pore distribution and cracks were investigated by using SEM photographs. Controlling preparation conditions were studied for reducing these defects. As a results, in acetone solution, the surface crack of samples was decreased with increasing PEG. On the contrary, the surface crack of sample was increasing with increasing the amount of EG. In ethanol solution without I
$_2$ , which was generally used for an electrolyte, the deposition time was longer than this of acetone. For that reason the sample deposition in ethanol time was needed with enough stirring time for suspending YBCO powder and deposition time. -
Alignment effects for nematic liquid crystal (NLC) using an in-situ photo-alignment method with obliquely polarized UV exposure on a polyirnide (PI) surface for homeotropic alignment were studied. The high pretilt angle in NLC can be measured by obliquely W exposure of
$30^{\circ}$ on the PI surface for 10~20 min. The pretilt angle of NLC generated using the in-situ photo-alignment was higher than that of a conventional photo-alignment method. -
This work aimed to develop ITO (Indium Tin Oxide) thin films ablation with a KrF Eximer laser required for the application in flat panel display, especially patterning into small geometry on a large substrate area. The threshold fluence for ablating ITO on glass substrate is about 0.1 J/cm
$^2$ . And its value is much smaller than using third harmonic Nd:YAG laser. Through the optical microscope measurement the surface color of the damaged ITO is changed into dark brown and irradiated spot is completely isolated form the undamaged surroundings by laser light. The XPS analysis showed that the relative surface concentration of Sn and In were essentially unchanged (In :Sn=5:1) after irradiating Eximer laser. Using aluminium mask made by second harmonic Nd:YAG laser the ITO patterning is carried out. -
We studied the viewing angle characteristics of a negative dielectric anisotropy nematic liquid crystal (NLC) using the new vertical-alignment (VA)-1/6 cell on a rubbed polyimide (PI) surface. Good voltage-transmittance (V-T)characteristics using the new VA-1/6 cell without a negative compensation film were obtained. The iso-viewing angle characteristics using the new VA-1/6 cell without the negative compensation film can be achieved.
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Using plasma-enhanced chemical vapor deposition (PECVD), carbon thin film as electron field emitter were fabricated. These carbon thin film were deposited on Si(100) substrate at several RF power. These film were estimated by raman spectroscopy, scanning electron microscopy, and field emission. The field electron emission property of these carbon thin film was estimated by a diode technique. As the result, we observed that the field emission properties of these films were promoted by higher RF power. These results are explained as change of surface morphology and structural properties of carbon thin film
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In this paper, we have studied minimization of the burr which occurred after
$\mu$ -BGA(ball grid array) singulation process, singulation of the multilayer with a pulsed Nd:YAG(266, 532 nm) laser is used to cut the metal layer which doesn't well absorb laser beam. Especially, the photoresist and$N_2$ blowing is effective to minimize of the surface demage and burr. In this experiment, the$N_2$ blowing reduces a laser energy loss by debris and suppress a surface oxidation. The SEM(scanning electron microscopes) and non-contact 3D inspector are used to measure cutting line-width and surface demage. The$\mu$ -BGA singulation threshold energy is 75.0 J/cm$^2$ at 30${\mu}{\textrm}{m}$ /s scan speed. -
ZnS:Cu phosphor used on powder electroluminescent device has a green emission in low frequency and a blue emission in high frequency. In this paper, to obtain the powder electroluminescent device of the blue emission in low frequency, the emission properties with mixed the ratio between phosphor and dye was investigated. The mixed ratio of the dye was from 0 to 5 weight percent. To inquire into the blue emission, the emission spectrum, the CIE coordinate system and the brightness were measured.
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Si thin films on p-type (100) Si substrate have been fabricated by pulsed laser deposition technique using a Nd:YAG laser. The pressure of the environmental gas during deposition was varied from 1 to 3 Torr. After deposition, Si thin film has been annealed again at nitrogen ambient. Strong violet-indigo photoluminescence have been observed from Si thin film annealed in nitrogen ambient gas. As increasing environmental gas pressure, weak green and red emissions from annealed Si thin films also observed by photoluminescence.
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We have investigated the photoinduced anisotropy in chalcogenide
$As_{40}Ge_{10}Se_{15}S_{35}$ thin films, non-doped and photodoped by Ag and Cu. The films were exposed by the linearly polarized He-Ne laser light($\lambda$ =632.8nm). The Ag and Cu photodoping resulted in reducing the time of saturation photoinduced linearly dichroism. Also photoinduced linearly dichroism was increased up to maximum 184% by Ag photodoping and 138% by Cu photodoping, respectively. As the result of this study, the linearly dichroism can be interesting for different applications of photoinduced anisotropy. In addition, it will offer lots of information for the photodoping mechanism and analysis of chalcogenide thin film. -
ZnO thin films for light emission device have been deposited on sapphire and silicon substrates by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of 355 nm. In order to investigate the emission properties of ZnO thin films, PL measurements with an Ar ion laser as a light source using an excitation wavelength of 351 nm and a power of 100 mW are used. All spectra were taken at room temperature by using a grating spectrometer and a photomultiplier detector. ZnO exhibited PL bands centered around 390, 510 and 640 nm, labeled near ultra-violet (UV), green and orange bands. Structural properties of ZnO thin films are analized with X-ray diffraction (XRD).
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Ferroeleclric 0.05PZN-xPZT(90/10)-(0.95-x)PZT(10/90) (x=0.65, 0.85) specimens were fabricated by the mixed-oxide method and cold-pressing method using sol-gel derived PZT(90/10) and PZT(10/90) powders. All specimens show a uniform ferroelectric grain without the presence of the pyrocholre phase. Average grain size increased with an increase in sintering temperature, the value for the x=0.65 specimen sintered at 125
$0^{\circ}C$ was 14.4$\mu$ m. The dielectric constant and dielectric loss of the x=0.65 specimen sintered at 125$0^{\circ}C$ were 1247, 2.06%, respectively. All specimens showed fairly good temperature and frequency stability of dielectric constant with the range from -2$0^{\circ}C$ to 6$0^{\circ}C$ and 100Hz to 10MHz. The coercive field and the remanent polarization of x = 0.65 specimen sintered at 125$0^{\circ}C$ were 8.5 kV/cm and 13$\mu$ C/cm$^2$ , respectively. The pyroelectric coefficient of the x=0.65 specimen sintered at 125$0^{\circ}C$ was 5.64$\times$ 10$^{-8}$ C/cm$^2$ K, respectively. -
The (1-x)MgTiO
$_3$ -xSrTiO$_3$ (x=0.03~0.04) ceramics were fabricated by the conventional mixed oxide method. The sintering temperature and time were 125$0^{\circ}C$ ~135$0^{\circ}C$ , 2hr., respectively. From the X-ray diffraction patterns, it was found that the perovskite SrTiO$_3$ and ilmenite MgTiO$_3$ structures coexisted in the (1-x)MgTiO$_3$ -xSrTiO$_3$ (x=0.03~0.04) ceramics. The dielectric constant($\varepsilon$ $_{r}$ ) was increased with addition of SrTiO$_3$ . The temperature coefficient of resonant frequency($\tau$ $_{f}$ ) was gradually varied from negative value to the positive value with increasing the SrTiO$_3$ . The negative temperature coefficient of resonant frequency of the magnesium titanate was adjusted to near zero at x=0.036, where the dielectric constant, quality factor, and$\tau$ $_{f}$ were 20.65, 95120, and +1.3ppm/$^{\circ}C$ , respectively. The temperature stability of qualify factor in (1-x)MgTiO$_3$ -xSrTiO$_3$ (x=0.03~0.04) ceramics increased as the amount of MgTiO$_3$ ./TEX>. -
The stability of
$Pr_6$ $O_{11}$ -based ZnO varistors doped with$Y_2$ $O_3$ was investigated under various d.c. stresses. The varistors were sintered at$1350^{\circ}C$ for 1h in the addition range of 0.0 to 4.0 mol%$Y_2$ $O_3$ . The varistors doped with$Y_2$ $O_3$ exhibited much higher nonlinearity than that without$Y_2$ $O_3$ . In Particular, the varistors containing 0.5 mol%$Y_2$ $O_3$ showed very excellent V-I characteristics, which the nonlinear exponent was 51.19 and the leakage current was 1.32$\mu\textrm{A}$ . And these varistors also showed an excellent stability, which the variation rate of the varistor voltage and the nonlinear exponent were -0.80% and -2.17%, respectively, under 4th d.c. stress, such as (0.80$V_ {1mA}$ /$90^{\circ}C$ /12h)+(0.85$V_{1mA}$ /$115^{\circ}C$ /12h)+(0.90$V_{1mA}$ /$120^{\circ}C$ /12h)+(0.95$V_{1mA}$ /$125^{\circ}C$ /12h). Consequently, since$Pr_ 6$ $O_{11}$ -based ZnO varistors doped with 0.5 mol%$Y_2$ $O_3$ have an excellent stability as well as good nonlinearity, it is expected to be usefully used to develop the superior varistors in future. -
Layered perovskite La
$_{2-x}$ Ca$_{l-x}$ Mn$_2$ O$_{7}$ phases were synthesized by solid state reaction. Single phase R-P could be obtained in the range of 0.4$_{2-x}$Ca $_{l-x}$ Mn$_2$ O$_{7}$ . About 30% of MR ratio was obtained at 270K when 5 T of magnetic field was applied.ied.ied.ied. -
In this paper, coplanar waveguide fed antennas (CPWFAs) insetting two slits to boundary of the square microstrip patch are presented. These slits play roles in not only lowering a resonant frequency but also fine-tuning for the proposed antenna together with open stub of CPW feed line. The CPWFAs were designed and manufactured using microwave dielectrics (Al,Mg)TaO
$_2$ having high dielectric-constant ($\varepsilon$ r=20). The return loss and input impedance of the CPWFAs were investigated in terms of the slit length and open stub length of CPW feed line. It is shown that a resonant frequency decreases as the slit length increases. -
The effect of CuO and CuO-B
$i_2$ $O_3$ additives on microwave dielectric properties of (P$b_{0.45}$ C$a_{0.55}$ )[F$e_{0.5}$ N$b_{0.5}$ )$_{0.9}$ S$n_{0.1}$ ]$O_3$ were investigated to decrease the sintering temperature for usage of Low Temperature Co-firing Ceramics (LTCC). The (P$b_{0.45}$ C$a_{0.55}$ )[F$e_{0.5}$ N$b_{0.5}$ )$_{0.9}$ S$n_{0.1}$ ]$O_3$ ceramics was sintered at 11$65^{\circ}C$ . In order to decrease the sintering temperature, CuO and Cuo-B$i_2$ $O_3$ were added in the (Pb,Ca)[(Fe,Nb)Sn]$O_3$ with CuO-B$i_2$ $O_3$ . For the addition of 0.4 wt.% CuO, the sintered density and the dielectric constant of the ceramics were revealed the maximum values of the 6.06g/c$m^2$ and 83 respectively and temperature coefficient of resonance frequency ($\tau$ $_{f}$ ) shifted to the positive value. As increasing B$i_2$ $O_3$ to the (Pb,Ca)[(Fe,Nb)Sn]$O_3$ with CuO-B$i_2$ $O_3$ with 0.2 wt.% CuO, the sintered density, the$\varepsilon$ $_{r}$ and the Q was decreased, and$\tau$ $_{f}$ was minimized at 0.2 wt.% CuO, and 0.2 wt.% B$i_2$ $O_3$ . For this composition, dielectric properties were$\varepsilon$ $_{r}$ of 81, Q.$f_{0}$ of 4400 GHz, and$\tau$ $_{f}$ of 5 ppm/$^{\circ}C$ at sintering temperature of 100$0^{\circ}C$ . the relationship between the microstructure and properties of ceramics was studied by X-ray diffraction(XRD), scanning electron microscopy(SEM).copy(SEM).oscopy(SEM).copy(SEM).EM). -
Thermal simulation of typical stack-type and newly proposed planar-type micro-gas sensors were studied by FEM method. the thermal analysis for the proposed planar structure including temperature distribution over the sensing layer and power consumption of the heater were carried using finite element method by computer simulation and well compared with those of typical stack-type micro-gas sensor. The thermal properties of the microsensor from thermal simulation were compared with those of an actual device to investigate the acceptability of the computer simulation.
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In this study, Tin oxide thin film for secondary battery was deposited on Pt/Ti/Si(100). It was fabricated by r.f. reactive sputtering with Tin metal target. At constant power (130W), pressure (Base 5
$\times$ 10$^{-6}$ Torr, working 5$\times$ 10$^{-3}$ Torr) and at room temperature, it was fabricated by Ar/O2 gas ratio. After deposition, we got AFM & SEM to investigated surface of thin films and had XRD to find crystalline of thin films. Charge/discharge characteristics were carried out in 1M LiPF$_{6}$ , EC:DMC = 1:1 liquid electrolyte using lithium metal at room temperature. -
In this work, all solid-state thin film supercapacitor(TFSC) was fabricated using tungsten trioxide (WO
$_3$ ) with a structure WO$_3$ /LiPON/WO$_3$ /Pt/TiO$_2$ /Si (substrate). After TiO$_2$ was deposited on Si(100) wafer by d.c. reactive sputtering, the Pt current collector films were grown on TiO$_2$ glue layer without breaking vacuum by d.c. sputtering. Fabrication conditions of WO$_3$ thin film were such that substrate temperature, working pressure, gas ratio of$O_2$ /Ar and r.f. power were room temperature, 5 mTorr, 20% (O$_2$ (8sccm)/Ar(32sccm)) and 200W, respectively. LiPON electrolyte film were grown on the WO$_3$ film using r.f. magnetron sputtering at room temperature. The XRD pattern of the as-deposited WO$_3$ thin film were shown no crystalline peak (amorphous). The SEM image of as-deposited WO$_3$ thin film showed that the surface is smooth and uniform. The capacitiy of as-fabricated TFSC was 0$\times$ 10$^{-2}$ F/$\textrm{cm}^2$ -${\mu}{\textrm}{m}$ . -
This paper described on the fabrication of SOI(Si-on-insulator) structures with buried cavities by SDB technology and eletrochemical etch-stop. The cavity was fabricated the upper handling wafer by Si anisotropic etch technique. SDB process was performed to seal the fabricated cavity under vacuum condition at -760mmHg. In the SDB process, captured air and moisture inside of the cavities were removed by making channels towards outside. After annaling(100
$0^{\circ}C$ , 60 min.), the SDB SOI structure was thinned by electrochemical etch-stop. Finally, it was fabricated the SDB SOI structure with buried cavities as well as an accurate control and a good flatness. -
The non-selective method by polishing after grinding was used widely to thinning of SDB SOI structures. This method was very difficult to thickness control of thin film, and it was dependent on equipments. However electrochemical etch-stop, one of the selective methods, was able to accurately thickness control and etch equipment was very simple. Therefore, this paper described with the effect of leakage current and electrodes on electrochemical etch-stop. Consequentially, PP(passivation potential) was changed according to the kinds of contact and contact sizes, but OCP(open current potential) was not change with range of -1.5~-1.3V
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This paper presents the characteristics of metal thin-film pressure sensors. The micro pressure sensors consists of a chrom thin-film, patterned on a Wheatstone bridge configuration, sputter-deposited onto thermally oxidized Si wafer an aluminium interconnection layer. The fabricated micro pressure sensors shows a low temperature coefficient of resistance, high-sensitivity, low non-linearity and excellent temperature stability. The sensitivity is 1.16~1.21 mV/V.kgf/
$\textrm{cm}^2$ in the temperature range of 25~l0$0^{\circ}C$ and the maximum non-linearity is 0.21 %FS. -
In this paper, we describe the results of a combined experimental theoretical study designed to understand and predict the dielectric properties of SF
$_{6}$ and SF$_{6}$ +Ar mixtures. The electron transport, ionization, and attachment coefficients for pure SF$_{6}$ and gas mixtures containing SF$_{6}$ has been analysed over the E/N range 30~300[Td] by a two term Boltzmann equation and by a Monte Carlo Simulation using a set of electron cross sections determined by other authors, experimentally the electron swarm parameters for 0.2[%] and 0.5[%] SF$_{6}$ +Ar mixtures were measured by time- of- flight method, The results show that the deduced electron drift velocities, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients and mean energy agree reasonably well with the experimental and theoretical for a rang of E/N values. Electron energy distribution functions computed from numerical solutions of the electron transport and reaction coefficients as functions of E/N. We have calculated$\alpha$ ,η and$\alpha$ -η the ionization, attachment coefficients, effective ionization coefficients, and (E/N), the limiting breakdown electric-field to gas density ratio, in SF$_{6}$ and SF$_{6}$ +Ar mixtures by numerically solving the Boltzmann equation for the electron energy distribution. The results obtained from Boltzmann equation method and Monte Carlo simulation have been compared with present and previously obtained data and respective set of electron collision cross sections of theections of the -
Poymeric insulators using in an heavy contamination area are easily attached to contaminants such as salt and by-products of industrial processes. To understand its effect on contaminants adhered to these insulators, we manufactured slurry mixed by some kaolin and salt as artificial contaminated solution. And then put samples in its slurry, for about one minute. And these samples are dried in natural condition for 6 days. We measured the degree of contaminant, AC leakage current for these contaminated samples.
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We investigated the fabrication of Si nanoparticle and
$C_{60}$ thin films by pulsed laser ablation. As a result, we observed visible green photoluminescence spectra in the Si/C$_{60}$ multilayer films after laser annealing. It is considered that this green photoluminescence is occurred from SiC particles, which is produced reaction of Si nanoparticles with$C_{60}$ via laser annealing.ing. -
Recently, a study of intellectual smell recognition system is applied for the various fields such as control of food processing and survey of decay. A basic gas recognition system was implemented gases using four metal oxides semiconductor sensors as inputs. A CPLD chip of twenty thousand gates level was used for this purpose. The CPLD chip was designed and the availability of the one chip smell recognition system was tested.
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We describe the preparation of a manganese oxide polymorph in which the solid-pore architecture of the material is controllably varied. All MnO
$_2$ gels derived from a KMnO$\_$ 4/-based sol-gel synthesis. The mesoporous structure of the initial gel is maintained by removingore fluid under conditions where the capillary forces that result fro extraction are either low or no existent. are either low or noexistent. Controlling both the pore and solid architecture on the nanoscale offers a strategy for the design of supercapacitor.