• 제목/요약/키워드: Temperature Swing

검색결과 101건 처리시간 0.029초

이중분사식 수소기관의 비정상 열부하 해석에 관한 연구 (A Study on Unsteady Thermal Loading of Hydrogen Engine with Dual Injection)

  • 위신환;김윤영;김홍준;이종태
    • 한국수소및신에너지학회논문집
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    • 제12권2호
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    • pp.147-155
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    • 2001
  • To measure of thermal loading in the combustion chamber of hydrogen engine with dual injection, instantaneous wall-surface temperature and unsteady heat flux of the cylinder head are measured and analyzed. The maximum wall surface temperature is shown in direct injection region which has large heat supplied. Partial and spatial temperatures have slight deviation in transient region of injection, though injection method change suddenly. All of thermal characteristics such as instantaneous temperature, temperature swing and heat flux of hydrogen engine with dual injection are remarkably higher than those of gasoline engine. It means necessity of additional countermeasure of thermal loading.

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Substrate 물질에 따른 a-IGZO TFT의 온도 특성 (Characteristics of a-IGZO TFT by the material of substrate and temperature)

  • 이명언;정한욱;박현호;최병덕
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.148-148
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    • 2010
  • Measuring the a-IGZO TFTs with various temperatures was found to induce a threshold voltage shift and a change of the subthreshold gate voltage swing. Characteristic change is dependant on a material of the substrate at the temperature from $20^{\circ}C$ to $100^{\circ}C$. The threshold voltage was shifted to the left from -2.7V to -61V on SiO2/galss. But, as the temperature increases form $20^{\circ}C$ to $100^{\circ}C$. the threshold voltage was shifted to the right from 0.85V to 2.45V.

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Burnable poison optimized on a long-life, annular HTGR core

  • Sambuu, Odmaa;Terbish, Jamiyansuren
    • Nuclear Engineering and Technology
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    • 제54권8호
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    • pp.3106-3116
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    • 2022
  • The present work presents analysis results of the core design optimizations for an annular, prismatic High Temperature Gas-cooled Reactor (HTGR) with passive decay-heat removal features. Its thermal power is 100 MWt and the operating temperature is 850 ℃ (1123 K). The neutronic calculations are done for the core with heterogeneous distribution of fuel and burnable poison particles (BPPs) to flatten the reactivity swing and power peaking factor (PPF) during the reactor operation as well as for control rod (CR) insertion into the core to restrain a small excess reactivity less than 1$. The next step of the study is done for evaluation of core reactivity coefficient of temperature.

IS cycle에서의 [DMIm]$MeSO_4$를 이용한 $SO_2/O_2$ 분리 ([ $SO_2/O_2$ ] Separation with [DMIm]$MeSO_4$ in IS Cycle)

  • 이기용;송광호;유계상;김홍곤;정광덕;김창수
    • 한국수소및신에너지학회논문집
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    • 제19권1호
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    • pp.49-55
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    • 2008
  • The feasibility of ionic liquid as a novel absorbent of $SO_2$ for the separation of $SO_2$ from $SO_2/O_2$ mixture in the thermochemical IS(Iodine-Sulfur) cycle was investigated. 1,3-dimethylimidazolium methylsulfate ([DMIm]$MeSO_4$) had shown twenty five times higher solubility of $SO_2$ than that of $O_2$. The dependence of $SO_2$ solubility by [DMIm]$MeSO_4$ on temperature and $SO_2$ partial pressure was examined, which confirmed the possibility of temperature and pressure swing for the separation process. Through cyclic absorption and desorption with temperature swing the stability of [DMIm]$MeSO_4$ in the separation process was also demonstrated. As a result of the experiments carried out, $SO_2$ separation from $SO_2/O_2$ mixture with ionic liquid([DMIm]$MeSO_4$) can be applied to the thermochemical IS cycle.

NVM IP용 저전압 기준전압 회로 설계 (Design of Low-Voltage Reference Voltage Generator for NVM IPs)

  • 김명석;정우영;박헌;하판봉;김영희
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2013년도 추계학술대회
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    • pp.375-378
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    • 2013
  • 본 논문에서는 EEPROM이나 MTP 등의 NVM 메모리 IP 설계에 필요로 하는 PVT(Process-Voltage-Temperature) 변동에 둔감한 기준전압(Reference Voltage) 회로를 설계하였다. 매그나칩반도체 $0.18{\mu}m$ EEPROM 공정을 이용하여 설계된 BGR(Bandgap Reference Voltage) 회로는 wide swing을 갖는 캐스코드 전류거울 (cascode current-mirror) 형태의 저전압 밴드갭 기준전압발생기 회로를 사용하였으며, PVT 변동에 둔감한 기준전압 특성을 보이고 있다. 최소 동작 전압은 1.43V이고 VDD 변동에 대한 VREF 민감도(sensitivity)는 0.064mV/V이다. 그리고 온도 변동에 대한 VREF 민감도는 $20.5ppm/^{\circ}C$이다. 측정된 VREF 전압은 평균 전압이 1.181V이고 $3{\sigma}$는 71.7mV이다.

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직분식 단기통 디젤기관 피스톤의 순간온도 측정에 관한 실험적 연구 (An Experimental Study on the Measurement of the Instantaneous Surface Temperature of the Piston of the DI Mono Cylinder Diesel Engine)

  • 이재순;이현구;강태경;이응래;정인곤;안병태
    • 한국자동차공학회논문집
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    • 제6권1호
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    • pp.196-204
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    • 1998
  • For the experimental measurement of instantaneous surface temperature of the piston of the DI mono cylinder diesel engine, the instantaneous temperature proves, data acquisition system, and grass-hopper type linkage system were developed. The instantaneous temperatures on the piston bowl, crown, lands and skirt were measured and analyzed, and the following conclusions were derived ; (i) The crank angle for the maximum instantaneous temperature during one cycle varies and moves back and forth by the measuring positions and engine speeds. (ii) The engine speeds, the positions of the measuring points and the cooling water temperature had an effect on the instantaneous temperature amplitude. (iii) The instantaneous temperature suing phenomena appeared on the temperature profiles of the piston crown, top and second land of ring, but on the temperature profiles of the parts of the third land of the fing and skirt, they didn't appear, (iv) The isothermal lines in the piston were acquired through the operation of the finite elements method using the measured temperatures as the boundary conditions.

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SOIL TEMPERATURE PREDICTION OF THE REGION OF THE SOUTHERN PART OF THE KOREA

  • Kim, Y. B.;H. S. Ha
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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    • pp.246-253
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    • 2000
  • The optimal equations to predict the soil tempratures of twelve cities in the region of the southern part of the Korea such as Changhung, Cheju, Chinju, Kwangju, Masan, Miryang, Mokpo, Muan, Pusan, Sogwipo, Ulsan, Yoosu, were suggested as function of time and soil depth and the time dependent variation and soil depth dependent distribution of temperature were analyzed for the back data of the geothermal energy utilization system design and agricultural usages. The equation form is $T(x,\;t)\;=\;T_{m}\;-\;T_{so}{\cdot}Exp(-\xi){\cdot}cos{\omega}(t\;-\;t_{o}\;-\;x\;/\sqrt{2{\alpha}{\omega}}$) and it can predict the soil temperatures well with the correlation factor of 0.98 or upwards for most data. The range of mean soil temperature was $14.99~18.53^{\circ}C$ and soil surface temperature swing, 11.65~14.54 days, soil thermal diffusivity, $0.025~0.069\;m^2/day$ except Mokpo of $0.100\;m^2/day$, and phase shift, 19.66~27.81 days. During about thirty years from 1960s to 1990s, the mean soil temperature was increased by $0.04~1.25^{\circ}C$. The temperature difference depending on soil depth was not significant.

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온도 가변에 따른 Large-grain-size TFT의 전기적 특성 변화 분석

  • 허남태;이원백;조재현;이준신
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.62-62
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    • 2009
  • Electrical properties of SGS-TFT with 5/5 ${\mu}m$ channel width and length which gate insulator is made of 20nm $SiO_2$ and 80nm $SiN_x$ was fabricated and measured at various temperatures. The field-effect mobility was decreased from 86.25 to 80.42 $cm^2/Vs$ and threshold voltage also decreased from -1.5792 to -1.0492 V, when temperature is increased from room temperature to $100^{\circ}C$. Subthreshold swing, also, increased from 0.3212 to 0.4818 V/dec and $I_{on/off}$ ratio decreased from $5.05{\times}10^7$ to $6.93{\times}10^5$.

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사상 이론을 이용한 파이프 원주 용접의 온도 분포 예측에 관한 연구 (A Study on Prediction of Temperature Distribution in Pipe Girth Welding by Mapping Theory)

  • 조영태;나석주
    • 대한기계학회논문집A
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    • 제24권12호
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    • pp.2935-2944
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    • 2000
  • Gas tungsten arc(GTA) welding is used to rrpiar the seat ring in swing type check valve in power plant because of its high weld quality. In order to automate the welding process, it is needed to analyze the process of inside pipe girth welding. In this study, the shapes of weld bead on pipe inside and outside were predicted and its validity was investigated. On the assumption that the welding arc had a bivariate gaussian distribution, analytical solution was derived to predict the temperature distribution in pipe weld using mapping under consideration of physical relationships. The size of weld bean could be predicted from this equation and its accuracy was verified by experiments.

압전식 압력센서에서 발생하는 열충격 효과 정량화 (Quantification of Thermal Shock in a Piezoelectric Pressure Transducer)

  • 이석환;최욱;배충식
    • 한국자동차공학회논문집
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    • 제13권5호
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    • pp.96-103
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    • 2005
  • One of the major problems limiting the accuracy of piezoelectric transducers fur cylinder pressure measurements in an internal combustion (IC) engine is the thermal shock. Thermal shock is generated from the temperature variation during the cycle. This temperature variation results in contraction and expansion of the diaphragm and consequently changes the force acting on the quartz in the pressure transducer An empirical equation for compensation of the thermal shock error was derived from consideration of the diaphragm thermal deformation and actual pressure data. The result indicate that the thermal shock equation provides reliable correction based on known surface temperature swing.