• 제목/요약/키워드: Various Temperature Condition

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Gate length에 따른 LDMOS 전력 소자의 고온동작 특성연구 (A Study on the High Temperature Characteristics of LDMOSFET under various Gate Length)

  • 박재형;구용서;구진근;안철
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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    • pp.13-16
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    • 2002
  • In this study, the electrical characteristics of 100v-Class LDMOSFET for high temperature applicat -ions such as electronic control systems of automo -biles and motor driver were investigated. Measurement data are taken over wide range of temperature(300k-SOOK) and various gate length(1.5 #m-3.0#m, step 0.3). In high temperature condition(>500k), drain current decreased over 30%, and specific on- resistance increased about three times in comparison with room temperature. Moreover, the ratio ROJBV, a figure of merit of the device, increased with increasing temperature.

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백삼건조 조건이 품질에 미치는 영향 (Effects of Drying Conditions on the Quality of White Ginseng)

  • 도재호;김상달
    • Journal of Ginseng Research
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    • 제9권2호
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    • pp.248-255
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    • 1985
  • In order to investigate the optimal drying condition of white ginseng by using bulk air drier(130 x 62 x 65cm), drying curves, diffusion coefficient at various drying temperature, the energy of activation, variation of color intensity and chemical components during drying of white ginseng were studied. Fick's second low of diffusion for diffusion out of spheres was successfully applied to describe the drying of white ginseng. It was found that the diffusion coefficient of water was 2.2x107, 9.0x107 cm2/sec at drying temperature 4$0^{\circ}C$, 55$^{\circ}C$, respectively. An Arrhenius type temperature dependency of moisture diffusivity was found, the energy of activation being 18.8 Kcal/g mol. Color intensity of white ginseng dried at various drying temperature was increased with an increase in drying temperature. The contents of crude protein, reducing sugar and crude saponin during drying of white ginseng were gradually decreased as increasing of drying time. And with the sensory evaluation by multiple comparison difference analysis, the optimal drying temperature of white ginseng was between 45$^{\circ}C$ and 5$0^{\circ}C$.

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원료 배합조건에 따른 발열보온재의 열적 특성 (Effect of Mixing Condition of Raw Materials on the Thermal Properties of the Exothermic & Insulating)

  • 김도준;신동엽;변승용;위창현;홍성훈;유병돈;오상훈
    • 소성∙가공
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    • 제18권5호
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    • pp.401-409
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    • 2009
  • The change of the thermal properties of exothermic and insulating materials with the mixing condition of raw materials which is the most important factor for exothermic & insulating materials was investigated by using the evaluation system of the thermal properties of exothermic and insulating materials. In this study, the effect of the thermal properties of the exothermic & insulating materials such as exothermic properties, endothermic properties, insulating properties, maximum temperature of molten metal, ignition time of exothermic & insulating materials and temperature recovery time on the mixing ratio of reductant and oxidant, types of reductant, and particle sizes of reductants was examined. It could be expected to design the mixing condition of raw materials for various exothermic and insulating materials.

원료 배합조건에 따른 발열보온재의 열적 특성 (Effect of Mixing condition of raw materials on the Thermal Properties of the Exothermic & Insulating Materials)

  • 김도준;신동엽;변승용;위창현;유병돈;오상훈
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2009년도 춘계학술대회 논문집
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    • pp.118-126
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    • 2009
  • The change of the thermal properties of exothermic & insulating materials with mixing condition of raw materials which is the most important factor for exothermic & insulating materials was investigated by using the evaluation system of the thermal properties of exothermic & insulating materials. In this study, the effect of the thermal properties of the exothermic & insulating materials such as exothermic properties, endothermic properties, insulating properties, maximum temperature of molten metal, ignition time of exothermic & insulating materials and temperature recovery time on the mixing ratio of reductant and oxidant, types of reductant, and particle sizes of reductants was examined. It could be expected to design the mixing condition of raw materials for various exothermic & insulating materials.

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다양한 외부 환경에서의 태양전지모듈의 열적 전기적 특성 평가 (Evaluation of Electric and Thermal Characteristics of Photovoltaic Module under Various Temperature and Irradiance Conditions)

  • 김경수;소정훈;강기환;유권종;윤순길
    • 한국태양에너지학회 논문집
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    • 제30권6호
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    • pp.125-130
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    • 2010
  • Normally, PV system is designed using local weather condition like lowest and highest temperature and irradiance. But this might give misleading results because it is not realistic data of PV module itself. To give more specific description of PV system, we tested photovoltaic(PV) modules' temperature, irradiance and maximum power generation characteristics from January to December in 2008 for 3kW PV system. From this, we could deeply analyze the accumulation temperature, electrical characteristics of PV module in various condition. So precise approach to PV system design can be done. The detail description is specified as the following paper.

플라즈마 이용 메탄 분해 특성 (Characteristics of $CH_4$ Decomposition by Plasma)

  • 김관태;이대훈;차민석;류정인;송영훈
    • 한국연소학회지
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    • 제10권4호
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    • pp.24-32
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    • 2005
  • Various types of plasma source applied in $CH_4$ decomposition process are compared. DBD by pulse and AC power, spark by pulse and AC power, rotating arc and hollow cathode plasma are chosen to be compared. The results show that $CH_4$ conversion per given unit power is relatively high in hollow cathode plasma and rotating arc that induces rather high temperature condition and that is why both thermal dehydration and plasma induced decomposition contribute for the overall process. In case of DBD wherein high temperature electron and low temperature gas molecule coexist, the process shows low conversion rate, for in rather low temperature condition the contribution of thermal dehydration is lowered. Selectivity of $C_2H_6$ and $C_2H_2$ is shown to be a good parameter of the relative contribution of plasma chemistry in the overall process. From the results we concluded that required condition of plasma source for a cost effective and high yield $CH_4$ decomposition is to have characteristics of both thermal plasma and non thermal plasma in which temperature is high above a certain threshold state for thermal dehydration and electron induced collision is maximized in the same breath.

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선박용 스프링강의 피로수명에 미치는 쇼트피닝의 영향 (A Effect of Shot Peening for Fatigue Life of Spring Steel for Vessel Application)

  • 유형주;박경동
    • Journal of Advanced Marine Engineering and Technology
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    • 제29권4호
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    • pp.426-435
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    • 2005
  • The lightness of components required in automobile and machinery industries is requiring high strength of components. Therefore this requirement is accomplished as the process of shot-peening method that the compressive residual stress is made on the metal surface as one of various improvement methods. Special research is, therefore, needed about compressive residual stress on the metal surface in the process of shot-peening method. Therefore, in this paper the effect of compressive residual stress of spring steel(JISG SUP-9) by shot-peening on fatigue crack growth characteristics in environmental condition(temperature) and mechanical condition(shot velocity, stress ratio) was investigated with considering fracture mechanics. By using the methods mentioned above, the following conclusions have been drawn. (1) The fatigue crack growth rate(da/dN) of the shot-peened material was lower than that of the un-peened one. In high temperature range. fatigue crack growth rate decreased with increasing temperature range, while fatigue crack growth rate increased by decreasing temperature in low temperature. (2) Fatigue life shows more improvement in the shot-peened material than in the un-peened material. And compressive residual stress of surface on the shot-peen processed operate resistance force of fatigue crack propagation.

극한 온도에서의 철도차량용 현가부품의 특성연구 (A Study on the Characteristics of the Suspension Components of Rolling Stocks in the Very low Temperature)

  • 최병일;나희승;장승호
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.45-48
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    • 2004
  • This study is a preview of characteristics of (1st/2nd) rubber suspension parts in low temperature, it will be researched before Trans Korean Railway and continental railway network connection. Rubber material characteristics are different to steel materials. Behavior of rubber material shows large deformation in hyper-elastic region. Moreover, added dashpot and low temperature condition shows various non-linear characteristics.

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열수화법으로 성장시 성장 온도에 따른 ZnO 나노 구조의 표면 형상 변화

  • 배영숙;김동찬;조형균
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.238-238
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    • 2009
  • In this work, we investigated the effect of the Zn complex concentration and growth temperature on the growth of ZnO nanorod by hydrothermal method. The ZnO nanorods were performed at condition of the various Zn complex concentration and growth temperature, 0.02 ~ 0.08 M and 60 ~ 80 $^{\circ}C$, respectably. We found from the SEM results that the diameter and length of ZnO nanorods were with increasing the growth temperature and Zn complex concentration. However, the growth condition in the two parameters wasmore than sensitive compared to Zn complex concentration on increasing the growth rate. From photoluminescence(PL) analysis, the strong band-edge emission for ZnO nanorod grown at 80 $^{\circ}C$ with 0.08 M indicated the fine crystallinity. Therefore, the diameter and length of ZnO nanorods have been able to control through the control of front growth parameters. Also, these ZnO nanorods grown low temperature will be available as building block for transparence flexible device applications.

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GFRP 리바의 내구성에 관한 연구 (A Study on the Durability of Glass Fiber Reinforced Plastics Rebars)

  • 문창권;김형열;박영환
    • 동력기계공학회지
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    • 제9권2호
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    • pp.50-56
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    • 2005
  • The mechanical properties of glass fiber reinforced polymer reinforcing bars(rebar) in various environment conditions such as moisture, chloride, alkali and freeze-thaw actions at temperature ranging from room temperature($25^{\circ}C$) to high temperature of up to $80^{\circ}C$ have been studied. The test results indicated that tensile strength and interfacial shear strength of GFRP bar were decreased with the increasing of temperature and holding time of each environment condition. The degradation in alkali environment. was more serious than those in the other environments.

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