• Current Research on Agriculture and Life Sciences
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• 제8권
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• pp.115-118
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• 1990

조류인 닭의 혈액을 PCV수치를 20%, 40% 및 60%로 임의로 변경시켜 자가혈장내에서 Westergren 방법에 의해 실온($27{\pm}1^{\circ}C$)과 저온($8{\pm}1^{\circ}C$)에서 적혈구 침강속도를 측정한 결과를 요약하면 다음과 같은 결과를 얻었다. 1. 닭에서 PCV수치가 작을수록 적혈구 침강속도는 증가되었다. 2. PCV수치를 변경시킨 닭의 혈액에서 반추수인 산양보다 적혈구 침강속도가 크게 나타났다. 3. PCV수치를 변경시킨 닭의 모든 혈액에서 시간경과에 따른 적혈구 침강속도는 직선상으로 나타났다. 4. PCV수치를 변경시킨 닭의 혈액에서 적혈구 침강속도는 저온에서 보다 실온에서 크게 나타났다.

• 조명전기설비학회논문지
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• 제28권3호
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• pp.26-31
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• 2014

High temperature fuel cell system, such as molten carbonate fuel cells(MCFC) and solid oxide fuel cells(SOFC), are capable of operating at MW rated power output. The power output change of high temperature fuel cell imposes the thermal and mechanical stresses on the fuel cell stack. To minimize the thermal-mechanical stresses on the stack and increase the systems reliability, we should divide the power plant configuration to several banks. However, the improvement of reliability in fuel cell power plant system causes an increase of the investment cost, for example, replacement costs, labor costs, and so on. For this reason - the balance between investment and reliability improvement - many studies about the appropriate level of investment have been conducted. In this paper, we evaluate the cost for operation and installation, the benefit for electric energy and thermal energy sales, and the system reliability for several cases : these cases relate with the bank configuration.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.381-381
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• 2011

In this study, a TiO2 colloidal sol was synthesized by sol-gel process, which was used as a "glue" agent to enhance interconnection of TiO2 particles in low temperature process for plastic dye sensitized solar cell. The crystalline phase of this TiO2 glue is pure anatase with average particles size of 5 nm, which was characterized by powder X-ray diffraction and high revolution-TEM. The viscous alcoholic paste without any organic binder was prepared from the mixture of commercial P25 powder and glue. Paste composition and sintering process parameters were optimized for high photovoltaic performance based on low temperature process. The electrochemical impedance spectroscopy and photocurrent-photovoltage transient spectroscopy were also employed to investigate the mechanism of electron transport in this binder free TiO2 film system.

• 대한기계학회논문집B
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• 제32권5호
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• pp.359-366
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• 2008

A two-dimensional thermal model of proton exchange membrane fuel cell with large active area is developed to investigate the performance of fuel cell with large active area over various thermal management conditions. The core sub-models of the two-dimensional thermal model are one-dimensional agglomerate structure electrochemical reaction model, one-dimensional water transport model, and a two-dimensional heat transfer model. Prior to carrying out the simulation, this study is contributed to set up the operating temperature of the fuel cell with large active area which is a maximum temperature inside the fuel cell considering durability of membrane electrolyte. The simulation results show that the operating temperature of the fuel cell and temperature distribution inside the fuel cell can affect significantly the total net power at extreme conditions. Results also show that the parasitic losses of balance of plant component should be precisely controlled to produce the maximum system power with minimum parasitic loss of thermal management system.

• 한국태양에너지학회 논문집
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• 제25권4호
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• pp.85-92
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• 2005

One of the most effective methods for utilizing solar energy is to combine thermal solar and optical energy simultaneously using a hybrid panel. Many systems using various kinds of photovoltaic panels have already been constructed. But utilizing solar energy by means of a hybrid panel with concentrator has not been to be attempted yet. Normally if sunlight is directed on the solar cell, and there is no increase in temperature, the absorption energy of each cell will increase per unit area. In a silicon solar cell. however, cell conversion efficiency decreases according to the increasing temperature. Therefore, to maintain cell conversion efficiency under normal condition, it is necessary to keep the cell at operating temperature. we design and make new hybrid panel with cooling system to prevent increasing of temperature on cell, collect effectively thermal energy. We compared performance of new hybrid panel with PV module and thermal panel. We also evaluated conversion efficiency, electric power and thermal capacity and confirmed cooling effect from thermal absorption efficiency.

• Journal of Electrochemical Science and Technology
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• 제13권2호
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• pp.208-212
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• 2022

In this paper, we report the effects of temperature on the deterioration of graphite-based negative electrodes during the longterm cycling of lithium-ion batteries (LIBs). After cycling 75 Ah pouch-type LIB full cells at temperatures of 45℃ (45-Cell) and 25℃ (25-Cell) until their end of life, we expected to observe changes in the negative electrode according to the temperature. The thickness of the negative electrode of the cell was greater after cycling; that of the electrode of 45-Cell (144 ㎛) was greater than that of the electrode of 25-Cell (109 ㎛). Cross-sectional scanning electron microscopy analysis confirmed that by-products caused this increase in the thickness of the negative electrode. The by-products that formed on the surface of the negative electrode during cycling increased the surface resistance and decreased the electrical conductivity. Voltage profiles showed that the negative electrode of 25-Cell exhibited an 84.7% retention of the initial capacity, whereas that of 45-Cell showed only a 70.3% retention. The results of this study are expected to be relevant to future analyses of the deterioration characteristics of the negative electrode and battery deterioration mechanisms, and are also expected to provide basic data for advanced battery design.

• 한국어류학회지
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• 제23권2호
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• pp.145-149
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• 2011

인위적 수온변화에 의한 미꾸라지 피부의 점액세포 반응을 확인하기 위해 고온($32^{\circ}C$)과 저온($4^{\circ}C$)에 적응시킨 실험군의 표피조직을 실온($18^{\circ}C$)의 대조군 집단과 비교 분석하였다. 그 결과, 고온적응 설험군에서는 대조군과 유의한 차이를 보이지 않았으나, 저온적응 실험군에서는 등, 체측, 후두부의 점액세포 수와 크기가 현저하게 증가하는 경향을 보였다(P<0.01). 또한 저온적응 실험군의 수온을 증가시켜 상온에서 재 적응시킨 결과에서도 피부 정액세포의 수와 크기가 현저히 감소하는 경향을 보였다(P<0.01). 따라서 미꾸라지 피부의 점액세포가 저온에 매우 민감하게 반응하는 양상은 어류의 조직학적 환경지표로서 유용할 것으로 여겨진다.

• 한국수소및신에너지학회논문집
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• 제24권1호
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• pp.50-60
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• 2013

High temperature proton exchange membrane fuel cells (PEMFCs) using phosphoric acid (PA) doped polybenzimidazole (PBI) membranes have been concentrated as one of solutions to the limits with traditional low temperature PEMFCs. However, the amount of reported experimental data is not enough to catch the operational characteristics correlated with cell performance and durability. In this study, design of experiments (DOE) based operational optimization method for high temperature PEMFCs has been proposed. Response surface method (RSM) is very useful to effectively analyze target system's characteristics and to optimize operating conditions for a short time. Thus RSM using central composite design (CCD) as one of methodologies for design of experiments (DOE) was adopted. For this work, the statistic models which predict the performance and degradation rate with respect to the operating conditions have been developed. The developed performance and degradation models exhibit a good agreement with experimental data. Compared to the existing arbitrary operation, the expected cell lifetime and average cell performance during whole operation could be improved by optimizing operating conditions. Furthermore, the proposed optimization method could find different new optimal solutions for operating conditions if the target lifetime of the fuel cell system is changed. It is expected that the proposed method is very useful to find optimal operating conditions and enhance performance and durability for many other types of fuel cell systems.

• 대한기계학회논문집B
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• 제31권2호
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• pp.125-131
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• 2007

This paper presents guideline for a practical design of the hybrid system combining a pressurized solid oxide fuel cell and a gas turbine. Design of the hybrid system based on a virtually designed gas turbine was simulated using models for off-design operation of the gas turbine. Two system configurations, with different method for supplying reforming steam, are considered and their design characteristics are compared. A higher design cell temperature provides better system performance. However, there exists a maximum allowable design cell temperature because the operating point of the compressor approaches the surge point with increasing fuel cell temperature. Increased pressure loss at the fuel cell moves the compressor operating point toward the surge point and reduces system performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.1298-1300
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• 1993

Compensation of temperature is very important to make high precision Load Cell. In this study, we developed a new type of load cell. The structure of the load cell has four strain gauges m single surface of the load cell. Also a new temperature compensation method is proposed and these, characteristics are better than previous one. This study will offer application to other type of load cell end another sensors.