• Title/Summary/Keyword: Sublimation

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Defect formation mechanism of 6H-SiC crystals grown by sublimation method

  • Kim, Hwa-Mok;Kyung Joo;Auh, Keun-Ho
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1998.09a
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    • pp.35-40
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    • 1998
  • There have two kinds of defects, planar defects and vertical defects which were called micropipes in SiC bulk crystals grown by a sublimation method. We could decrease these defects by adding a little piece of Si in the SiC powder or using Ta cylinder in the crucible. so were report the dependence of these defects in a wafer on silicon/carbon ratio in this paper. The chemical species sublimed from SiC powder is affected by carbon from the graphite wall of the crucible. It is important to control the chemical species on the substrate.

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Heat transfer enhancement in electronic modules using a turbulence promoter (난류촉진체에 의한 전자칩의 열전달촉진에 관한 연구)

  • 박시우;정인기
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.6
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    • pp.861-870
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    • 1999
  • An experimental study was carried out to investigate the effects of using various shapes of turbulence promoter on the heat-transfer enhancement of 2-D and 3-D arrays of rectangular modules in a rectangular channel for design of noiseless and low-powered cooling fan in the electronic systems. Measurements of heat/mass transfer coefficients were made using a naphthalene sublimation technique, and the friction factors were measured for Reynolds numbers in the range$3.3{\time}10^3$~$1.6{\time}10^4$. Flow visualization was peformed by oil-film method. It was found that heat transfer and pressure drop increased remarkably due to the existence of the promoter. The results of the performance evaluation based on equal pumping power were showed that substantial heat-transfer enhancement was obtained at low Reynolds number range by use of a turbulence promoter.

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A Study on Heat Transfer Enhancement from Flat Plate Using Multiple Tripping Wires (복수 트리핑 와이어를 사용한 평판에서의 열전달 촉진에 관한 연구)

  • Yoo, Seong-Yeon;Cho, Woong-Sun;Ahn, Jong-Kyu
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.12
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    • pp.837-845
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    • 2012
  • The purpose of this research is to investigate the heat transfer enhancement by the multiple tripping wires installed on a flat plate. Naphthalene sublimation technique is used to measure the local mass transfer coefficients, and then heat transfer coefficients are calculated using heat/mass transfer analogy. Experiments are performed for the developed and developing flow conditions. Local and average heat transfer coefficients from the flat plate with three tripping wires are compared with those of no and one tripping wire. Remarkable heat transfer enhancements are found resulting from the boundary layer separation by the tripping wires, especially in the laminar boundary layer.

Growth and Characteristics for $CdS_{0.69}Se_{0.31}$ single crystal by sublimation method (승화법에 의한 $CdS_{0.69}Se_{0.31}$ 단결정 성장과 특성)

  • Hong, Kwang-Joon;You, Sang-Ha;Kim, Jang-Bok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.157-158
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    • 2006
  • $CdS_{0.69}Se_{0.31}$ single crystal grown by sublimation method. Hall effect measurement were carried out by the Van der Pauw method. The measurement values under the temperature were found to be carrier density $n\;=\;1.95\;{\times}\;10^{23}m^3$, Hall coefcient $RH\;=\;-3.21\;{\times}\;10^{-5}m^3/c$, conductivity ${\sigma}\;=\;362.41\;{\Omega}^{-1}m^{-1}$, and Hall mobility ${\mu}\;=\;1.16\;{\times}\;10^{-2}m^2/v.s$.

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The theoretical Model for predicting the behaviors of the frost formation (착상 거동예측을 위한 이론적 모델)

  • Lee, Gwan-Su;Lee, Tae-Hui;Heo, Jeong-Hei
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.3
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    • pp.1096-1105
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    • 1996
  • A theoretical model of the frost formation has been presented to investigate the characteristics of the growth of frost layer by considering molecular diffusion of water vapor and heat generation caused by sublimation of water vapor in the frost layer. The present model was compared with existing experimental data as well as a previous model. The difference between the present model and existing experimental data was found to be about 6 percent. An analysis for the behavior of frost formation using present model shows a good agreement with the trend for a number of experimentally observed features. The present analysis can also provide the physical understanding on the phenomena of the frost formation.

Aesthetic Education into the Internal Logic and Practice Path of Rural Characteristic Industrial Construction

  • Lu Ziyan
    • International Journal of Advanced Culture Technology
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    • v.11 no.4
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    • pp.273-278
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    • 2023
  • Aesthetic education in a variety of forms in the sublimation of the people's feelings, sublimation of the soul. It is of great significance to inherit and develop rural culture and to maintain cultural diversity. At present, rural characteristic industry is an important form of development to promote rural economic development, protect rural cultural diversity and continue rural culture. It is of great practical significance to guide the development direction of rural characteristic industry, strengthen the value connotation of rural characteristic industry and stimulate the endogenous power of rural characteristic industry. At the same time, it is of great significance to promote the development of aesthetic education and broaden the path of aesthetic education.