• Title/Summary/Keyword: 온도구배

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Determination of Polarity in Trap Carriar by Temperature Gradient Thermally Stimulated Measurement (온도구배 열자격 측정에 의한 Trap Carriar의 국성판정)

  • 권영수;강도영;국상훈
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1989.06a
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    • pp.29-34
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    • 1989

  • A Thermally stimulated measurement using a temperature gradient has been applied to the study of charged particles and their polarity in polymer. Our experimental results on a cross-linked polysthylen(XLPE) film can be obtained, observing the TSC peaks of the trapped carriers in C peak determinated negative polarity that is electron.

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Determination of Charged Particles and their Polarity by Temperature Gradient Thermally Stimulated Measurement (온도구배 열자격 측정에 의한 하전입자의 구별 및 극성 판정)

  • 권영수;강도열;국상훈
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.8
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    • pp.600-609
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    • 1989

  • A thermally stimulated measurement using a temperature gradient has been applied to the study of charged particles and their polarity n polymers. From the experimental results on a cross-linked polyethylene (XLPE) film is found that the TSC peaks of the trapped carriers in C peak are due to the negative polarity which is electron and the ionic carriers having negative polarity show D peak.

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Separations of polystyrene sulfonate by dual pump field flow fractionation using UF hollow fiber membranes (듀얼펌프 중공사막 흐름 장 흐름 분회법을 사용하여 다당류(Polystyrene sulfonate)의 분리)

  • 정도연;최승렬;이승윤;민병렬
    • Proceedings of the Membrane Society of Korea Conference
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    • 2004.05b
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    • pp.192-194
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    • 2004

  • FFF에서 외부장은 시료의 종류에 따라 선택적으로 사용되며, 그 외부장의 종류에 따라 세부기술로 구분되어진다. 원심력(gravitational or centrifugal field)을 외부장으로 사용하는 침강장-흐름분획법(sedimentation FFF)은 지름이 0,05∼1um정도인 콜로이드 입자의 분리에 좋은 방법이다. 온도구배(thermal fradient)를 이용하는 열장-흐름분획법(thermal FFF)은 유기 고분자의 분리 및 고분자의 물성연구에 이용된다.(중략)

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Effects of stabilizing temperature gradients on thermal convection in rectangular enclosures during phsysical vapor trnasport (승화법에 의한 단결정성장공정에서 이중온도구배가 대류현상에 미치는 영향)

  • 김극태;최장우;이민옥;권무현;권순길
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.1
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    • pp.94-100
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    • 1999

  • Mercurous chloride($Hg_2Cl_2$) crystals hold promise for many acousto-optic and opto-electronic applications, which are prepared in closed ampoules by the physical vapor transport(PVT) growth methods. The thermal boundary conditions established by imposing different temperature on sidewalls of the enclosure cause simultaneous horizontal and vertical convectie flow in the PVT processes of$Hg_2Cl_2$ . It is found that for the ratios of horizontal to vertical thermal Rayleigh numbers$Ra_H/Ra{\ge}1.5$, the convective flow structure changes from multicellular to unicellular for the base parametric state of Ra=($2.79{\times}10^4$) , Pr=0.91, Le=1.01, Pe=4.60, Ar=0.2 and$C_V =1.01$. For the $\Delta T^{*}_H$ greater than 0.3, the $$\mid$U$\mid$_{max}$is increased with increasing $\Delta$ T^{*}_H$ and decreasing the aspect ratio. For the aspect ratios ranging from 0.1 to 1.0, there is a direct and linear relationship between $$\mid$U$\mid$_{max}$ and $\sqrt{{\Delta}T^_H\;^{\ast}}$.A decrease in the aspect ratio destabilizes the convective flow and results in an increase of the magnitude of convection in the crystal growth reactor. The vertical gradient tends to destabilize the convective flow which leads to oscillations, whereas the horizontal gradient stabilizes the convection.

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