• Title/Summary/Keyword: Electric probe

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Study on Graft Polymerization of Acrylate and Methacrylate Monomers onto the Carbon Black Surface (Carbon Black 표면에의 아크릴레이트 및 메타크릴레이트의 그라프트 중합에 관한 연구)

  • Goo, Hyung-Seo;Chang, Byung-Kwon;Kim, Yong-Moo;Choi, Kyu-Suk
    • Applied Chemistry for Engineering
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    • v.5 no.3
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    • pp.395-405
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    • 1994
  • The various functional groups, such as hydroxyl(-OH), carboxyl(-COOH) and quinonic oxygen(OC<) on the carbon black(abbreviated to CB) surface were activated with n-butyl lithium solution in n-hexane and then acrylate and methacrylate monomers were graft polymerized onto these activated anionic sites and CB-grafted polymers were obtained. To separate homopolymers from reaction mixture, non-solvent precipitation method or centrifugal separating method were applied. Subsequently, conversion, grafting ratio and efficiency were determined at various reaction temperatures and times. In case of acrylates, the grafting ratio showed 20~30% but methacrylates showed 150~200%. Also the anion polymerizations between CB and monomers were nearly reached to equilibrium state within one or two hours under each reaction temperatures but conversion and grafting ratio were increased a little with reaction temperature increase. In colloidal dispersion stability test, before heat-drying, the all CB-grafted polymers showed good dispersed stability in good solvents for acrylic and methacrylic homopolymers. Futhermore, CB-polymethacrylates were found to show excellent collidal properties for good solvents of methacrylic homopolymer even after heat-drying. Identification of the grafted polyacrylates and polymethacrylates onto the CB surface was performed by FT-IR spectroscopy. In addition, electric resistance values of CB-grafted polymers were measured by Four-probe method, and the increase of the grafting ratio showed the increase of the surface resistance.

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A Study on Properties of a Near-Field Microwave Microscope Using a Waveguide Resonator (도파관 공진기를 이용한 마이크로파 근접장 현미경의 특성에 관한 연구)

  • Kim, Hyun;Kim, Song-Hui;Kim, Joo-Young;Lee, Kie-Jin
    • Journal of the Korean Society for Nondestructive Testing
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    • v.28 no.1
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    • pp.16-24
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    • 2008
  • Near-field scanning microwave microscope (NSMM) has been used to characterize the electromagnetic properties of samples based on a cavity perturbation technique. We used a NSMM using a waveguide cavity to couple a metallic probe tip as a point like evanescent field emitter. We explained the quality of our NSMM system by applying the cavity perturbation theory. First, to make a shape perturbation, we inserted linear and loop probes in the waveguide resonator. To check up electric and magnetic field distribution inside the waveguide resonator by shape perturbation, we confirmed the field distribution by using a HFSS simulation. Second, to make material perturbation, we located a dielectric sample in front of the probe tip and measured reflection coefficient $(S_{11})$. We found that the resonance frequency$(f_r)$ was changed linearly as the dielectric constant of resonator$({\varepsilon}_r)$ increased when ${\Delta}{\varepsilon}\;and\;{\Delta}{\mu}$ were small.

The Effect of Transcutaneous Electrical Nerve Stimulation on Acute Pain and Beta-Endorphins of Needle Biopsy (경피신경전기자극이 전립선 침생검 조직검사 시 통증과 혈장 베타 엔돌핀 농도에 미치는 효과)

  • Lee, Ji-Min;Hong, Hae-Sook
    • Journal of Korean Biological Nursing Science
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    • v.15 no.3
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    • pp.99-106
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    • 2013
  • Purpose: The purpose of this study was to examine the effect on plasma beta endorphin concentration level and the influences on pain score of transcutaneous electrical nerve stimulation (TENS) mediation to patients During a prostate needle biopsy. Methods: TENS was administered to only the experimental group. The electric current was given in high frequency (40-100 pps) and low intensity ($2-50{\mu}s$) from the waiting room stage until the end of the procedure. The average time spent was 35 minutes. Following 10 minutes of retention in the rectum, there was a biopsy. In two groups, the pain score was assessed twice when vas pain penetrated into the rectum, during the needle biopsy. The Beta endorphin concentration level was assessed through blood gathering 2 times in the Nuclear Medicine Labs before and after the test. Results: There was not much difference in pain levels from both groups when a microscope probe penetrated into the rectum and in the time when tissues were collected. However, the average overall pain level was reduced during those two procedures. The plasma beta endorphin level was increased in the TENS medicated group compared with the unmedicated group after the procedures were completed. Conclusion: The research indicates that TENS was desirable to be considered as a non-invasive method for controlling pain.

자기펄스압축성형법 및 방전 플라즈마 소결법의 연속공정을 이용한 $95%Bi_2Te_3-5%Bi_2Se_3$ 소결체제조 및 열전특성평가

  • Lee, Cheol-Hui;Kim, Hyo-Seop;Kim, Taek-Su;Gu, Ja-Myeong;Hong, Sun-Jik
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.48.2-48.2
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    • 2011
  • 열전재료는 열과 전기에너지의 상호 변환이 가능한 재료로 이를 이용한 응용제품의 개발이 크게 주목을 받고 있으며, 특히 $Bi_2Te_3$계 합금의 경우 상온에서 가장 우수한 성능지수를 가지는 재료로 많은 연구가 진행되고 있다. 그러나 기존의 $Bi_2Te_3$계 합금은 일방향응고법으로 제조되어 많은 시간과 비용을 필요로 하고, 특히 C축의 Van der Waals 결합으로 인해 기계적 강도가 약하다는 단점이 있었다. 최근 분말야금법을 이용하여 기계적강도를 높이고, 격자산란에 의한 열전도도의 감소로 성능지수를 높일수 있는 방법들이 제시되고 있다. 본 연구에서는 급속응고공정인 가스분무법을 이용하여 n-type의 $95%Bi_2Te_3-5%Bi_2Se_3$분말을 제조하였고, 이 재료의 경우 성형조건에 따라 조직이 쉽게 변하기 때문에 이를 제어하기 위해 단시간동안 고압으로 성형가능한 자기펄스압축성형법(Magnetic Pulsed Compaction)을 이용하여 성형체를 제조하였다. 제조된 성형체는 밀도를 증가시키고 결정립성장을 억제시킬수 있는 방전플라즈마소결법(Spark Plasma Sintering)을 이용하여 소결체로 제조되었으며, 각각의 공정이 열전성능에 미치는 영향을 고찰하였다. OM (Optical Microscope) 및 SEM (Scaning Electric Microscope)을 이용하여 미세구조를 관찰하였고 XRD (X-Ray Diffraction)를 이용하여 상의 변화를 분석하였으며, 상온에서 경도를 측정함으로서 공정조건에 따른 기계적강도를 비교하였다. Seebeck계수는 시편의 양단에 온도차를 주어 발생하는 기전압을 측정하여 계산하였고, 전기비저항은 4point probe방법으로 측정하였다. 전하이동도 및 전하농도는 Hall측정으로부터 구하였고 열전도도를 측정하여 종합적인 열전성능을 평가하였다.

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A Study on the Structure Fabrication of LDD-nMOSFET using Rapid Thermal Annealing Method of PSG Film (PSG막의 급속열처리 방법을 이용한 LDD-nMOSFET의 구조 제작에 관한 연구)

  • 류장렬;홍봉식
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.12
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    • pp.80-90
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    • 1994
  • To develop VLSI of higher packing density with 0.5.mu.m gate length of less, semiconductor devices require shallow junction with higher doping concentration. the most common method to form the shallow junction is ion implantation, but in order to remove the implantation induced defect and activate the implanted impurities electrically, ion-implanted Si should be annealed at high temperature. In this annealing, impurities are diffused out and redistributed, creating deep PN junction. These make it more difficult to form the shallow junction. Accordingly, to miimize impurity redistribution, the thermal-budget should be kept minimum, that is. RTA needs to be used. This paper reports results of the diffusion characteristics of PSG film by varying Phosphorus weitht %/ Times and temperatures of RTA. From the SIMS.ASR.4-point probe analysis, it was found that low sheet resistance below 100 .OMEGA./ㅁand shallow junction depths below 0.2.mu.m can be obtained and the surface concentrations are measured by SIMS analysis was shown to range from 2.5*10$^{17}$ aroms/cm$^{3}$~3*10$^{20}$ aroms/cm$^{3}$. By depending on the RTA process of PSG film on Si, LDD-structured nMOSFET was fabricated. The junction depths andthe concentration of n-region were about 0.06.mu.m. 2.5*10$^{17}$ atom/cm$^{-3}$ , 4*10$^{17}$ atoms/cm$^{-3}$ and 8*10$^{17}$ atoms/cm$^{3}$, respectively. As for the electrical characteristics of nMOS with phosphorus junction for n- region formed by RTA, it was found that the characteristics of device were improved. It was shown that the results were mainly due to the reduction of electric field which decreases hot carriers.

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Evaluation of Eddy Current Signals from the Inner Wall Axial Cracks of Steam Generator Tubes (증기발생기 전열관의 내면 축방향 균열에 대한 ECT 특성 평가)

  • Choi, Myung-Sik;Hur, Do-Haeng;Lee, Doek-Hyun;Park, Jung-Am;Han, Jung-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.5
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    • pp.501-509
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    • 2001
  • For the enhancement of ECT reliability on the primary water stress corrosion cracks of nuclear steam generator tubes, of which the occurrence is on the increase, it is important to comprehend the signal characteristics on crack morphology and to select an appropriate probe type. In this paper, the sizing accuracy and the detectability for the inner wall axial cracks of tubes were quantitatively evaluated using the following specimens: the electric discharge machined notches and the corrosion cracks which were developed on the operating steam generator tubes. The difference of eddy current signal characteristics between pancake and axial coil were also Investigated. The results obtained from this study provide a useful information for more precise evaluation on the inner wall axial tracks oi stram generator tubes.

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Signal Characteristics of Eddy Current Test for Intergranular Attack of Steam Generator Tubes (증기발생기 전열관의 입계부식에 대한 와전류검사 신호특성)

  • Choi, Myung-Sik;Lee, Deok-Hyun;Cho, Se-Gon;Yim, Chang-Jae;Han, Jung-Ho;Hur, Do-Haeng
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.2
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    • pp.198-202
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    • 2002
  • Beacuse intergranular attack (IGA), one of the locallized corrosion forms occurring on steam generator tubes, can not be fabricated by an electric discharge machining method, there are few data for the eddy current test (ECT) characteristics of IGA. In this paper, the characteristics of eddy current signals are evaluated using nonexpanded tubes with IGA defects formed in 0.1 M sodium tetrathionate solution at $40^{\circ}C$. The detectability and sizing accuracy of IGA were discussed in terms of the coil type and frequency of the ECT probes.

Fabricatiion and Characterization of ${Bi_2}{Sr_2}{CaCu_2}{O_8}$ Superconductor Thick Films on Cu Substrates using Cu-free Precursors (Cu-free 전구체를 이용하여 구리 기판 위에 ${Bi_2}{Sr_2}{CaCu_2}{O_8}$ 초전도 후막의 제조 및 특성)

  • 한상철;김상준;한영희;성태현;한병성
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.4
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    • pp.349-358
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    • 2000
  • Fabrication and Characterization of Bi$_{2}$/Sr$_{2}$/CaCu$_{2}$/O$_{8}$(Bi2212) superconductor thick films were fabricated successfully on C tapes by liquid reaction between Cu-free precursors of Bi$_{x}$/SrCaO/$_{y}$(x=1.2-2) and Cu tapes. Cu-free Bi-Sr-Ca-O powder mixtures were screen-printed on Cu tapes and heat-treated at 850-87$0^{\circ}C$ for several minutes in air oxygen nitrogen and low oxygen pressure. In order to obtain the optimum heat-treatment condition we studied the effect of the precursor composition the printing thickness and the heat-treatment atmosphere on the superconducting properties of Bi2212 films and the reaction mechanism. Microstructures and phases of thick films were analyzed by films and the reaction mechanism. Microstructures and phases of thick films were analyzed by optical microscope and XRD. The electric properties of superonducting films were examined by the four probe method. At heat-treatment temperature the thick films were in a partially molten state by liquid reaction between CuO of the oxidized copper tape and the precursors which were printed on Cu tapes. During the heat-treatment procedure Bi2212 superconducting particle nucleate and grow in preferred orientations.ons.s.

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Evaluation of OH Radical Generation to Nanotube Morphology of TiO2 Nanotube Plate (TiO2 nanotube plate의 nanotube 형태에 따른 OH radical 생성량 평가)

  • Lee, Yongho;Pak, Daewon
    • Journal of Korean Society on Water Environment
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    • v.32 no.5
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    • pp.403-409
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    • 2016
  • In this study, a TiO2 nanotube was grown on a titanium plate by using anodic oxidation method for the evaluation of TiO2 nanotube morphology. The TiO2 nanotube was grown in an electrolyte containing ethylene glycol, 0.2 wt% of NH4F and 2 vol% of H2O. Applied voltage varied from 30 to 70 V and the morphology of the TiO2 nanotube was observed. After anodization, a TiO2 nanotube plate was immersed in 35℃ ethanol for 24 hours. Anatase and rutile crystal forms of TiO2 nanoutbe were observed after annealing. 4-chrolobenzoic acid, a probe compound for OH radicals, was dissolved in H2O in order to measure the OH radical. Liquid chromatography was used to check the concentration of the 4-chrolobenzoic acid. The OH radical generation by TiO2 nanotube plate was proportionate to the length of the TiO2 nanotube. Furthermore, when the number of TiO2 nanotube plate increased, the OH radical generation increased as well.

Pulsed Magnetron Sputtering Deposit ion of DLC Films Part I : Low-Voltage Bias-Assisted Deposition

  • Oskomov, Konstantin V.;Chun, Hui-Gon;You, Yong-Zoo;Lee, Jing-Hyuk;Kim, Kwang-Bok;Cho, Tong-Yul;Sochogov, Nikolay S.;Zakharov, Alexender N.
    • Journal of the Korean institute of surface engineering
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    • v.36 no.1
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    • pp.27-33
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    • 2003
  • Pulsed magnetron sputtering of graphite target was employed for deposition of diamond-like carbon (DLC) films. Time-resolved probe measurements of magnetron discharge plasma have been performed. It was shown that the pulsed magnetron discharge plasma density ($∼10^{17}$ $m^{-3}$ ) is close to that of vacuum arc cathode sputtering of graphite. Raman spectroscopy was sed to examine DLC films produced at low ( $U_{sub}$ / < 1 kV) pulsed bias voltages applied to the substrate. It has been shown that maximum content of diamond-like carbon in the coating (50-60%) is achieved at energy per deposited carbon atom of $E_{c}$ =100 eV. In spite of rather high percentage of $sp^3$-bonded carbon atoms and good scratch-resistance, the films showed poor adhesion because of absence of ion mixing between the film and the substrates. Electric breakdowns occurring during the deposition of the insulating DLC film also thought to decrease its adhesion.