• Title/Summary/Keyword: Hot-Cold

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Fabrication of a Micro Cooler using Thermoelectric Thin Film (열전박막을 이용한 마이크로 냉각소자 제작)

  • Han, S.W.;Choi, H.J.;Kim, B.I.;Kim, B.M.;Kim, D.H.;Kim, O.J.
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1459-1462
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    • 2007
  • In general a thermoelectric cooler (TEC) consists of a series of P type and N type thermoelectric materials sandwiched between two wafers. When a DC current passes through these materials, three different effects take place; Peltier effect, Joule heating effect and heat transfer by conduction due to temperature difference between hot and cold plates. In this study we have developed a micro TEC using $Bi_2Te_3$ (N type) and $Bi_{0.5}Sb_{1.5}Te_3$ (P type) thin films. In order to improve that performance of a micro TEC, we made 10 um height TE legs using special PR only for lift-off. We measured COP (coefficient of performance) and temperature difference between hot and cold connectors with current.

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Mechanical Properties of High Stength Sheet Steels for Auto-Body by Induction Heat Treatment (고주파열처리에 의한 자동차용 고강도 강판의 기계적 성질변화)

  • Lee, D.H.;Yoon, C.S.;Lim, J.D.
    • Journal of the Korean Society for Heat Treatment
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    • v.17 no.2
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    • pp.73-77
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    • 2004
  • The efforts which increase the strength of the auto-body structure and decrease its weight lead to develop a new concept of part production systems, such as Post-Form Strengthening by induction heat treatment. In this study, several cold and hot-rolled sheet steels were used to find out optimum induction heat treatment conditions. After induction heat treatment, strength of heat-treated sheet steels was increased significantly compared with that of as-rolled steels. From these results, auto-body structure which has more light and safe has been made by using this induction hardening method.

Evaluation of Durability on MMA-Modified Polymer Paste for Coating materials (코팅재로서 MMA 개질 폴리머 페이스트의 내구성능 평가)

  • Yeon, Kyu-Seok;Lee, Hyun-Jong;Joo, Myung-Ki;Jin, Xing-Qi;Lee, Chi-Won
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.807-810
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    • 2005
  • In this study, MMA-modified paste of coating material for protecting the concrete structures was developed. The coating material was applied to cement concrete specimens by brush, roller and spray in each of which one, two and three layers to survey, by the cold-hot iterative test, the neutralization test, the chloride ion permeation test and the ante-abrasion test, the affect of painting methods and layers influencing on the durability of coating material. Results of the cold-hot iterative test showed that, regardless of the painting methods and layers, the defects such as crack or fuzz on surface were not produced. As the number of painting layers increased, the neutralization prevention as well as the chloride ion permeation prevention effects were increased. On the other hand, no difference was found between the painting methods. Reducing weight by abrasion of polymer paste coating material was $20\%$ comparing to that of cement mortar.

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Development of On-Line Monitoring System using Smart material (지적복합재료를 이용한 온라인 모니터링시스템 개발)

  • Lee, Jin-Kyung;Park, Young-Chul;Lee, Sang-Pill;Park, Yi-Hyun
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.67-71
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    • 2003
  • A hot press method was used to create the optimal fabrication condition for a Shape Memory Alloy(SMA) composite. The bonding strength between the matrix and the reinforcement within the SMA composite by the hot press method was more increased by cold rolling. In this study, the objective was to develop an on-line monitoring system in order to prevent the crack initiation and propagation by shape memory effect in SMA composite. Shape memory effect was used to prevent the SMA composite from crack propagation. For this system an optimal AE parameter should be determined according to the degree of damage and crack initiation. When the SMA composite was heated by the plate heater attached at the composite, the propagating cracks could be controlled by the compressive force of SMA.

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The evaluation of friction factor according to materials and lubricants (재료 및 윤활제에 따른 전단 마찰 상수값과 평가)

  • 김동진
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.03b
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    • pp.119-124
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    • 1999
  • Quantitative evaluation of the tribological conditions at the tool-workpiece interface in metal forming is usually accomplished by the ring-compressinon. test This paper describes an experimental investigation into shear friction factor under cold and hot forming conditions according to materials and lubricants using the ring compression test. Six different materials and five different lubricants were applied in the experiments. calibration curves with the friction coefficient were obtained using FEM analysis and verified by the verified by the experimental results. The influence of materials and lubricants level on friction are discussed. In the ring compression test the shear friction factor has a different from steels and aluminum water base graphite lubricants on cold working conditions and hot working conditions.

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Use of thermography in Thoroughbred horses (말에서 체열촬영술의 응용)

  • Yang, Young-Jin;Cho, Gil-Jae;Nam, Tchi-Chou;Choi, Seok-Hwa
    • Korean Journal of Veterinary Research
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    • v.42 no.2
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    • pp.269-275
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    • 2002
  • The aim of this study was to investigate the usefulness and effectiveness of thermography in horse. Total 21 horses associated with locomotors, wound, and ophthalmic disease were investigated. Thermographically, the wannest area in normal limb was coronary band ($27.26^{\circ}C$), and carpus, metacarpus, fetlock, and pastern area were $26.64^{\circ}C$, $24.42^{\circ}C$, $23.64^{\circ}C$ and $23.06^{\circ}C$, respectively. The temperature($^{\circ}C$) of horses with lameness, swelling, nervous, ataxia was lower(cold spot) than surrounding tissue or symmetry area, and with heat, signs of inflammation was increased(hot spot). These results suggest that the thermography is useful for the early detection of locomotors, wound, and ophthalmic disease in horse and an excellent adjunct to clinical examination.

Effects of hot-boning process and cold-batter mixing technology on protein denaturation control system for low-sodium poultry products - NRF2012 Postdoc Fellowship Report (나트륨 저감화 식육가공기술로써 단백질 변성 제어를 위한 hot-boning과 cold-batter mixing 기술의 유효성 고찰 - 연구재단 박사후연수 내용을 중심으로)

  • Lee, Hong Chul
    • 축산식품과학과 산업
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    • v.5 no.2
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    • pp.58-69
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    • 2016
  • 건강지향의 식육, 육제품에 대한 사회적 요구에 부응하기 위해 기능성 첨가물 대체 연구로부터 원재료인 신선육과 가공공정 중 식육 단백질의 변성을 제어하고 최적화하기 위한 연구과제로써 온도체 가공/급속동결송풍냉각/저온 세절혼합 조합 기술(처리구)에 대한 유효성이 평가되었다. 그 결과 새로 제안된 조합 공정기술은 기존의 냉도체/수침냉각/세절혼합 조합(대조구)과 비교했을 때 단백질 변성 제어를 통한 기능성 단백질 추출성의 향상으로 인해 신선육의 품질향상뿐만 아니라 가열 처리 후 단백질 겔의 수율과 조직감 모두 증진되었으며, 특히 나트륨을 저감화한 조건($2%{\rightarrow}1%$)에서도 기존의 대조구와 유사한 특성을 보여 나트륨 저감화를 위한 기술로 제안될 수 있었다.

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Food of China Yunnan Baizu (증국 운남성 백족의 음식문화)

  • Shin, Kye-Sook
    • Journal of the Korean Society of Food Culture
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    • v.15 no.3
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    • pp.225-232
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    • 2000
  • The Purpose of this study was to understand the China Yunnan Baizu food. This study was performed a visit market based on in- depth interview with food experts those who lived in Baizu province. The results were summarized as follows. The main food of Baizu were Bab, Dduk(BaBa), Nuddle(Mi xian) made from rice. They ate all kind of food from vegetables, fish, and pork, but the remarkable thing was that there were practical limit to select the ingredient. They would use some fermented products such as Pao-chai, Yan-chai, Zha. Pao-chai was fermented vegetables like Kimchi, Yan-chai was similar with Changachi in Korea, and Zha was prepared from meat and fish. Menus for Banquets were included 8 kinds of cold appetizer, 8 kinds of hot dishes, and 2 kinds of sweet desserts. The ingredients were local products and they considered hot, sour, cold taste importantly. The method of cooking was simple and Rusan, Sengpi was the most traditional Baizu food. Ru san is one of dishes prepared from the milk, and milk pedimented product. Sengpi was uncooked pork.

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A Study on Environmental Improvement of Indoor Air Quality in University Dormitory (대학교 기숙사의 실내공기질 환경 개선에 관한 연구)

  • Kim, Ho-Jin;Yang, Jeong-Hoon;Seok, Ho-Tae
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1398-1405
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    • 2008
  • As the structure, material and construction of building develop continuously, so the recent residential buildings are being large, high-rise and group. High-rise residential buildings consume a lot of energy on supplying cold and hot water. As well, high-rise residential buildings bring on discomfortable use and unexpected conditions on account of faucet outlet pressure rise and the difference of water supply pressure between top floor and bottom floor. Thus, the purpose of this study is to research on using conditions of cold and hot water supply system through survey and field measurement in high-rise residential buildings and to analyze problems.

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A Study on the Mechanical Characteristic in Al 6061 Alloys welded by Friction Stir Welding (Al 6061 합금의 마찰교반접합시 접합부의 역학적 특성에 관한 연구)

  • 방한서;김흥주;고민성;장웅성
    • Journal of Welding and Joining
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    • v.20 no.3
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    • pp.105-108
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    • 2002
  • Al-alloy is utilized widely as a light-weight material to an automobile, a vessel and many kind of equipment, due to the light-weight and its characteristics that is a good tensile strength, elongation and tenacity for bearing heavy load and weight. Al-alloy has the good property of hot working, cold working and corrosion-resistant. But the exiting fusion welding by using Al has some economical and technical problems, but on the other hand, Friction Stir Welding (FSW) that is new joining method can settle the disadvantages that occur to the fusion welding and Is being applied and extended into the various industry fields. On this study, To analyze accurately the mechanical properties of joining area by FSW in Al 6061 alloy by using finite analysis program with finite element method. The size of HAZ and the thermal distribution is simulated and the mechanical properties around the FSW joining area to the Al-alloy 6061 is examined.