• Title, Summary, Keyword: Electric probe

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Thermal and Electrical Behaviors of Polyethylene Oxide/Polyaniline Fibers Prepared by Electrospinning Method (전기방사법에 의해 제조된 폴리에틸렌옥사이드/폴리아닐린 섬유의 열적 및 전기적 거동)

  • Kim, Seok;Cho, Mi-Hwa;Park, Soo-Jin
    • Applied Chemistry for Engineering
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    • v.17 no.1
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    • pp.16-21
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    • 2006
  • In this study, PEO blend fibers mixed with polyaniline (PANI)/10-camphor sulfonic acid (CSA) and PANI/dodecylbenzene sulfonic acid (DBSA) were electro spun to investigate the influence of PANI content. CSA and DBSA were used as a functionalized doping acid having a bulky volume. PANI/PEO blend solution was prepared by dissolving PEO and PANI doped with CSA or DBSA. The thermal properties were measured by thermogravimetric analyzer (TGA). As a result, with increasing of the PANI content in PANI/CSA and PANI/DBSA, although initial decomposition temperature (IDT) was decreased, thermal stability was increased due to the increase of $A^*{\cdot}K^*$ and integral procedural decomposition temperature (IPDT). The electrical conductivities measured by the 4-probe method. The electric conductivity was increased with increasing of PANI content in PANI/CSA and PANI/DBSA. However, electrical conductivity did not change significantly beyond 30% content of PANI. From CV results, PANI/CSA showed the better defined peak shpae and higher peak current density compared to PANI/DBSA. This was probably related to the slightly higher electrical conductivity or better morphology for easy charge transfer in the case of PANI/CSA.

Fabrication of Multiple-Frequency Exposure System for In Vitro Experiment (세포 실험용 다중 주파수 동시 노출 장치 제작)

  • Kim, Tae-Hong;Seo, Min-Gyeong;Mun, Ji-Yeon;Pack, Jeong-Ki
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.2
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    • pp.213-219
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    • 2012
  • Recently, we are simultaneously exposed by various electromagnetic sources due to an increase of mobile communication services. However, EMF(Electric, Magnetic and Electromagnetic Field) study has been performed mainly about only single frequency. The objective of this paper is to develop an multiple-frequency exposure system for in vitro experiment. The exposure unit for in vitro experiments was designed by radial transmission line type to get broadband characteristics to generate signals of CDMA at 836.5 MHz and WCDMA at 1950 MHz frequency simultaneously. The modulated signals were delivered to the conical antenna through amplifier, digital attenuator and RF combiner. SAR values were obtained by the averaged values of 3 measured values at 9 points in petri dish using the fiber optic temperature probe. The measured return loss was under -15 dB. For 1 W input power, the mean value and standard deviation of SAR were $0.105{\pm}0.019$ for the CDMA frequency and $0.262{\pm}0.055$ for the WCDMA frequency.

Noninvasive Method to Distinguish between Glucose and Sodium Chloride Solution Using Complementary Split-Ring Resonator (Complementary Split Ring Resonator(CSRR)를 이용한 포도당과 염화나트륨 수용액의 비침습적 구별)

  • Jang, Chorom;Park, Jin-Kwan;Yun, Gi-Ho;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.4
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    • pp.247-255
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    • 2018
  • In this work, glucose solution and sodium chloride solution were distinguished noninvasively using a microwave complementary split-ring resonator (CSRR). Based on the electrical properties of the two solutions measured using a open-ended coaxial probe, a CSRR was designed and fabricated for operation at a specific frequency that facilitates differentiating the two solutions. Furthermore, a polydimethylsiloxane mold was fabricated to concentrate the solution at a region where the electric field of the resonator was strongest, and a laminating film was used to prevent contact between the solution and resonator. Experiments were performed by dropping $50{\mu}L$ of the solution in steps of 100 mg/dL up to a maximum human blood glucose level of 400 mg/dL. Our experiments confirmed that the transmission coefficients ($S_{21}$) of glucose solution and sodium chloride solution exhibit variations of -0.06 dB and 0.14 dB, respectively, per 100 mg/dL concentration change at the resonance frequency. Thus, the opposite trends in the variation of $S_{21}$ with change in the concentration of the two solutions can be used to distinguish between them.

The Effect of Au Addition on the Hardening Mechanism in Ag-25wt% Pd-15wt% Cu (Ag-25wt% Pd-15wt% Cu 3원합금(元合金) 및 Au 첨가합금(添加合金)의 시효경화특성(時效京華特性))

  • Bea, B.J.;Lee, H.S.;Lee, K.D.
    • Journal of Technologic Dentistry
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    • v.20 no.1
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    • pp.37-49
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    • 1998
  • The specimens used were Ag-25 Pd-15 Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electric furnace and centrifugal casting machine in Ar atmosphere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at $350{\sim}550^{\circ}C$ Age- hardening characteristics of the small Au-containing Ag-Pd-Cu dental alloys were investigated by means of hardness testing. X-ray diffraction and electron microscope observations, electrical resistance, ergy dispersed spectra and electron probe microanalysis. Principal results are as follows : Hardening occured in two stages, i.e., stage I in low temperature and stage II in high temperature regions, during continuous aging. The case of hardening in stage I was due to the formation of the $L1_0$ type face-centered tetragonal PdCu-ordered phase in the grain interior and hardening in stage I was affected by the Cu concentration. In stage II, decomposition of the ${\alpha}$ solid solution to a PdCu ordered phase($L1_0$ type) and an Ag-rich ${\alpha}2$ phase occurred and a discontinuous precipitation occurred at the grain boundary. From the electron microscope study, it was conclued that the cause of age-hardening in this alloy is the precipitation of the PdCu ordered phase, which has AuCu I type face-centered tetragonal structure. Precipetation procedure was ${\alpha}{\to}{\alpha}+{\alpha}_2+PdCu {\to}{\alpha}_1+{\alpha}_2+PdCu$ at Pd/Cu = 1.7 Ag-Pd-Cu alloy is more effective dental alloy as ageing treatment and is suitable to isothermal ageing at $450^{\circ}C$.

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The Effect of Au Addition on the Hardening Mechanism in Ag-30wt%Pd-10wt%Cu Alloy (Ag-30wt% Pd-10wt% Cu 3원합금(元合金) 및 Au 첨가합금(添加合金)의 시효경화특성(時效硬化特性))

  • Lee, K.D.;Nam, S.Y.
    • Journal of Technologic Dentistry
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    • v.21 no.1
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    • pp.27-41
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    • 1999
  • The Ag-Pd-Cu alloys containing a small amount of Au is commonly used for dental purposes, because this alloy cheaper than Au-base alloys for clinical use. However, the most important characteristic of this alloy is age-hardenability, which is not exhibited by other Ag-base dental alloys. The specimens used were Ag-30Pd-10Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electric furnace and centrifugal casting machine in Ar atmosphere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at 350-$550^{\circ}C$ Age-hardening characteristic of the small Au-containing Ag-Pd-Cu dental alloys were investigated by means of hardness testing, X-ray diffraction and electron microscope observations, electrical resistance, differential scanning calorimetric, energy dispersed spectra and electron probe microanalysis. Principal results are as follows ; Maximum hardening occured in two co-phases of ${\alpha}_2$ + PdCu In stage II, decomposition of the $\alpha$ solid solution to a PdCu ordered phase($L1_o$ type) and an Ag-rich ${\alpha}_2$ phase occurred and a discontinuous precipitation occurred at the grain boundary. From the electron microscope study, it was concluded that the cause of age-hardening in this alloy is the precipitation of the PdCu redered phase, which has AuCu I type face-centered tetragonal structure. Precipitation procedure was ${\alpha}{\to}{\alpha}_1+PdCu{\to}{\alpha}_2+PdCu$ at Pd/Cu = 3 Pd element of Ag-Pd-Cu alloy is more effective dental alloy on anti-corrosion and is suitable to isothermal ageing at $450^{\circ}C$.

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