• Title, Summary, Keyword: conductivity

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Correlation Between Lateral Photovoltaic Effect and Conductivity in p-type Silicon Substrates

  • Lee, Seung-Hoon;Shin, Muncheol;Hwang, Seongpil;Park, Sung Heum;Jang, Jae-Won
    • Bulletin of the Korean Chemical Society
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    • v.34 no.6
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    • pp.1845-1847
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    • 2013
  • The lateral photovoltaic effect (LPE) can be observed in semiconductors by irradiating a light spot position between electrodes on sample's surface. Because lateral photovoltaic voltage (LPV) is sensitively changed by light spot position, a LPE device has been tried as a position-sensitive detector. This study discusses the correlation between LPV and conductivity in p-type silicon and nano-structured Au deposited p-type silicon (nano-Au silicon), respectively. Conductivity measurement of the sample was carried out using the four-wire method to eliminate contact resistance, and conductivity dependence on LPV was simultaneously measured by changing the light irradiation position. The result showed a strong correlation between conductivity and LPV in the p-type silicon sample. The correlation coefficient was 0.87. The correlation coefficient between LPV and conductivity for the nano-Au silicon sample was 0.41.

Microstructure and Properties of Mg-RE-Zn Alloys for High Conductivity Parts (고전도성 부품용 Mg-RE-Zn계 합금의 미세조직 및 특성)

  • Kim, Jeong-Min;Kim, Nam-Hoon
    • Journal of Korea Foundry Society
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    • v.34 no.5
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    • pp.151-155
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    • 2014
  • The relatively low conductivity of conventional Mg-Al alloys often limits their areas of application. Therefore, several attempts to develop new high-conductivity magnesium alloys have been made recently. In this research, A Ce-rich rare-earth (RE)material and zinc were added to magnesium which contained no aluminum. As the RE and Zn content were increased, both the hardness and tensile strength were gradually increased, despite the fact that the electrical conductivity decreased slightly. The effects of an aging treatment on the conductivity and mechanical properties of Mg-RE-Zn alloys were also investigated. The electrical conductivity did not change according to the heat treatment conditions; however, the mechanical properties could be enhanced by proper aging heat treatments.

A NOTE ON UNIQUENESS AND STABILITY FOR THE INVERSE CONDUCTIVITY PROBLEM WITH ONE MEASUREMENT

  • Kang, Hyeon-Bae;Seo, Jin-Keun
    • Journal of the Korean Mathematical Society
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    • v.38 no.4
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    • pp.781-791
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    • 2001
  • We consider the inverse conductivity problem to identify the unknown conductivity $textsc{k}$ as well as the domain D. We show hat, unlike the case when $textsc{k}$ is known, even a two or three dimensional ball may not be identified uniquely if the conductivity constant $textsc{k}$ is not known. We find a necessary and sufficient condition on the Cauchy data (u│∂Ω, g) for the uniqueness in identification of $textsc{k}$ and D. We also discuss on failure of stability.

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The Influence of Aniline to Acid Composition on the Electrical Conductivity of PANI-PAAMPSA

  • Yoo, Joung Eun;Bae, Joonho
    • Bulletin of the Korean Chemical Society
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    • v.34 no.12
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    • pp.3825-3828
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    • 2013
  • In this study, the influences of aniline to acid composition were investigated on the electrical conductivity of PANI-PAAMPSA. The ratio of aniline to sulfonic acid groups was optimized for the maximum conductivity of PANI-PAAMPSA. The conductivity is strongly correlated with the electronic structure of PANI-PAAMPSA; the highest conductivity of PANI-PAAMPSA was observed when PANI has the longest conjugation length.

A Study on Electrical Conduction of As-Te-Si-Ge Amorphous Semiconductor (As-Te-Si-Ge 유리질 반도체의 전기전도에 관한 연구)

  • Park, Chang-Yeub;Wang, Jin-Seok;Jeong, Hong-Bae
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.12 no.2
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    • pp.18-23
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    • 1975
  • The dc conductivity, ac conductivity and switching effect of As.Te-Si.Ge have beon investigated. The dc conductivity ranged from $3{\times}10^{-7}{\Omega}^{-1}cm^{-1}$ to $1.5{\times}10^{-8}{\Omega}^{-1}cm^{-1}$ at room temperature and was found to be expressed by ${\sigma}$ = ${\sigma}_0$exp(-${\Delta}$E/kT) below the phase transition temperature Tg. The ac conductivity was much higher than dc conductivity and this result is consistent to experimental formula ${\sigma}$(w)=${\sigma}_0+Aw^n$. In the temperature range of 298$^{\circ}K$ ~ $473^{\circ}K$ the ac conductivity was independent of temperature at 200KHs. At lower frequencies the ac conductivity increased strong1y with temperature. Also, it has been found that all samples showed a threshold switching, but not a memory switching.

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Relationship between Hydraulic Conductivity and Electrical Conductivity in Sands (사질토의 투수계수와 전기전도도 간의 상관관계)

  • Kim, Jinwook;Choo, Hyunwook;Lee, Changho;Lee, Woojin
    • Journal of the Korean Geotechnical Society
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    • v.31 no.6
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    • pp.45-58
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    • 2015
  • The aim of this study is to suggest a semi-empirical equation for estimating the hydraulic conductivity of sands using geoelectrical measurements technique. The suggested formula is based on the original Kozeny-Carman equation; therefore varying factors affecting the Kozeny-Carman equation were selected as the testing variables, and six different sands with varying particle sizes and particle shapes were used as the testing materials in this study. To measure both hydraulic and electrical conductivities, a series of constant head permeameter tests equipped with the four electrodes conductivity probe was conducted. Test results reveal that the effects of both pore water conductivity and flow rate in relation between hydraulic conductivity and formation factor (=pore water conductivity / measused conductivity of soil) of tested materials are negligible. However, because the variations of hydraulic conductivity of the tested sands according to particle sizes are significant, the estimated hydraulic conductivity using the formation factor varies with particle sizes. The overall comparison between the measured hydraulic conductivity and the estimated hydraulic conductivity using the suggested formula shows a good agreement, and the variation of hydraulic conductivity with varying Archie's m exponents is smaller compared with varying porosities.

Low Temperature Thermal Conductivity of Sheath Alloys for High $T_{c}$ Superconductor Tape

  • Park, Hyung-Sang;Oh, Seung-Jin;Jinho Joo;Jaimoo Yoo
    • Transactions on Electrical and Electronic Materials
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    • v.1 no.2
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    • pp.32-37
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    • 2000
  • Effect of alloying element additions to Ag on thermal conductivity and electrical conductivity of sheath materials for Bi-Pb-Sr-Ca-Cu-O(BSCCO) tapes has been characterized. The thermal conductivity at low temperature range (10~300K) of Ag and Ag alloys were evaluated by both direct and indirect measurement techniqueas and compared with each other, It was observed that the thermal conductivity decreases with increasing the content of alloying element such as Au, Pd and Mg. Thermal conductivity of pure Ag at 3 0K was measured to be 994.0 W(m.K) on the other hand, the corresponding values of $Ag_{0.9995}Mg_{0.0005}$, $Ag_{0.974}$, $Au_{0.025}$, $Mg_{0.001}$, $Ab_{0.973}$, $Au_{0.025}$, $Mg_{0.002}$ and $Ag_{0.92}$, $Pb_{0.06}$, $Mg_{0.02}$ were 342.6, 62.1, 59.2 and 28.9 W(m.K), respectively, indicating 3 to 30 times lower than that of pure Ag. In addition, the thermal conductivity of pure Ag measured by direct and indirect measurement techniques was 303.2 and 363.8 W(m.K) The difference in this study is considered to be within an acceptable error range compared to the reference data.

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Study on Change of Thermal Conductivity According to Environmental Conditions (환경 조건에 따른 열전도율 변화에 관한 연구)

  • Seo, Eun-Seok;Kim, Bong-Joo;You, Nam-Gyu;Hong, Sang-Hun;Kim, Han-Nah;Jung, Ui-In
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.66-67
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    • 2019
  • Insulated buildings are exposed to the external environment due to aging and construction problems, resulting in a decrease in building energy efficiency. Therefore, the purpose of this paper is to provide a material for the change in thermal conductivity of the insulation when it is exposed to various external environments. In the experiment, five types of heat insulating materials were selected, stored under different environmental conditions, and the thermal conductivity was measured periodically to confirm the change in thermal conductivity. As a result, the thermal conductivity of all the insulating materials except the PF board increased with the passage of time. This is because thermal insulation absorbs atmospheric moisture under all environmental conditions and the thermal conductivity increases, and in the case of thermal insulation stored indoors in environmental conditions, the temperature differs from the thermal insulation stored outside. It is considered that there is little evaporation of moisture absorbed constantly, and the change in thermal conductivity is large.

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Relationship Between Electrical Conductivity, Exchangeable Sodium Percentage and pH During Desalinization of Reclaimed Tidelands (간척지토양의 제염과정중 전기전도도와 치환성 나트륨 백분율 및 pH 사이의 관계)

  • 구자웅;은종호
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.30 no.4
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    • pp.127-133
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    • 1988
  • This study was performed to obtain the basic data analyzing salt movement and desalinization effects, and two different desalinization experiments through leaching and rinsing were carried out, using samples of silt loam soil and silty clay loam soil collected in reclaimed tidelands. The relationships between the electrical conductivity of saturation extract and the electrical conductivity at various dilutions, and the correlations between electrical conductivity, total salt concentration, exchangeable sodium percentage and pH during the desalinization of reclaimed tidelands, were analyzed by the statistical method. The results obtained from this study were summarized as follows: 1.The sample soils used in this study were saline-sodic soils in accordance with the USDA classi- fication system of salt affected soils. 2.The electrical conductivity of saturation extract could be estimated conveniently, using the electrical conductivity of extract from various different soil-water suspensions. 3.The total salt concentration could be expressed in the electrical conductivity, but there was a little difference by soil textures. 4.The regression analysis showed that the relationship between the electrical conductivity of saturation extract and the exchangeable sodium percentage during the desalinization of reclaimed lands could be described by a linear regression equation. 5.The value of pH showed a tendency to increase according as the exchangeable sodium percentage decreased during the desalinization of reclaimed tidelands.

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Improvement of Thermal and Electrical Conductivity of Epoxy/boron Nitride/silver Nanoparticle Composite (열전도도 및 전기전도도가 향상된 에폭시/보론나이트라이드/은나노입자 복합체의 제조)

  • Kim, Seungyong;Lim, Soonho
    • Korean Chemical Engineering Research
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    • v.55 no.3
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    • pp.426-429
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    • 2017
  • In this study, we investigated the effect of BN (boron nitride) on the thermal and the electrical conductivity of composites. In case of epoxy/BN composites, the thermal conductivity was increased as the BN contents were increased. Epoxy/AgNP (Ag nanoparticle) nanocomposites exhibited a slight change of thermal conductivity and showed a electrical percolation threshold at 20 vol% of Ag nanoparticles. At the fixed Ag nanoparticle content below the electrical percolation threshold, increasing the amount of BN enhanced the electrical conductivity as well as thermal conductivity for the epoxy/AgNP/BN composites.