• 한국수소및신에너지학회논문집
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• 제12권4호
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• pp.287-292
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• 2001

The optical transmittance change of Pd thin film due to hydrogen absorption and desorption was examined at room temperature. Hydrogen absorption and desorption cycling effects on optical transmittance were measured 6 times in the pressure range between 0 and 640 torr. Optical transmittance of Pd film was increasing with increasing hydrogen pressure. Ratio of optical transmittance to the change of pressure at $\beta$ phase is bigger than that of low hydrogen pressure range.

• 한국수소및신에너지학회논문집
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• 제29권5호
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• pp.490-496
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• 2018

Recently, the power and refrigeration cogeneration based on Kalina cycle has attracted much attention for more efficient utilization of low-grade energy. This study presents a thermodynamic performance analysis of a cogeneration cycle of power and absorption refrigeration based on Kalina cycle. The cycle combines Kalina cycle (KCS-11) and absorption cycles by adding a condenser and an evaporator between turbine and absorber. The effects of ammonia mass fraction and separation pressure were investigated on the system performance of the system. Results showed that the energy utilization of the system could be greatly improved compared to the basic Kalina cycle.

• 설비공학논문집
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• 제8권2호
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• pp.187-197
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• 1996

A computer program for thermal design analysis has been developed to predict the operating characteristics and performance of an absorption heat pump to recover $30{\sim}40^{\circ}C$ of waste hot water. The effects of heat transfer area of the system components, temperature and mass flow rate of heat transfer medium, and solution circulation rate on the system performance are investigated in detail. The results obtained indicate that the COP is increased with a decrease in the temperature of driving steam and with an increase in the temperature of waste hot water while the COP is little affected by the variation of a hot water temperature. It is also found that the heating output is increased with an increase in the temperature of waste hot water and driving steam as well as with a decrease in the temperature of hot water. The simulation results are also compared with the experimental results for a periodic operation of the system and obtained a satisfactory agreement.

• 대한기계학회논문집B
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• 제34권2호
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• pp.145-151
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• 2010

본 연구에서는 지열발전 등과 같은 저온 열원을 에너지원으로 하는 발전에 응용될 수 있는 흡수식 동력 사이클의 출력 최적화를 수행하였다. 이를 위해 정상상태 사이클 시뮬레이션을 수행하여 사이클의 성능을 고찰하였다. 시뮬레이션은 열원과 열침의 입구온도 및 유량을 고정한 상태에서 수행하였으며, 일반적인 발전소의 열원-열침 유량비를 고려하였다. 사이클의 성능은 두 개의 독립변수를 이용하여 나타내었는데, 이는 분리기 입구 암모니아 농도와 터빈 입구 압력이다. 시뮬레이션 결과, $100^{\circ}C$의 지열수와 $20^{\circ}C$의 냉각수(지열수 유량의 5배) 조건에서, 흡수식 동력 사이클을 이용하면 지열수 유량 1 kg/s 당 최대 약 14 kW의 출력을 얻을 수 있음을 보였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1249-1254
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• 2008

Industrial low temperature waste heat exists sparse in surroundings but its amount is huge. However, large portion of waste heat is discarded due to its poor recovery quality and inferior application technologies. The heat pump system in this research is based on the hybrid combination of compression cycle and absorption cycle in order to recycle various kind of industrial waste heat effectively. The prime objective is to design a compression absorption hybrid heat pump system which can produce high temperature above the level of $90^{\circ}C$ and low temperature of $20^{\circ}C$ at the same time using waste heat water of $50^{\circ}C$. A mathematical simulation was carried out as a basis to design a prototype 3 RT class hybrid heat pump. From the simulation results, fundamental parameters to design the system were obtained.

• 한국토양비료학회지
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• 제14권4호
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• pp.201-209
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• 1982

'80년도(年度)는 수도재배기간중(水稻栽培期間中) 이상저온(異常低溫)이 계속(繼續)되었으며 냉해피해(冷害被害)가 컸으므로 냉해(冷害)의 양상(樣相)과 정도(程度) 및 영양흡수(營養吸收)와의 관계(關係)를 조사(調査)한 결과(結果)는 다음과 같았다. 1. '80년도(年度) 벼의 냉해(冷害)는 수도생육(水稻生育) 후기(後期)에 계속(繼續)된 저온(低溫) 및 일조부족(日照不足)과 더불어 감수분열기(減數分裂期)에 있었던 생식생장(生殖生長) 한계온도(限界溫度) 이하(以下)의 저온(低溫)에 크게 영향(影響)을 받았기 때문인 것으로 사료(思料)된다. 2. 삼요소중(三要素中) 질소무시용구(窒素無施用區)에서 냉해피해(冷害被害)가 적었으며 질소시용량(窒素施用量)이 많을수록 냉해(冷害)가 심(甚)한 경향(傾向)이었고 삼요소(三要素) 균형시비(均衡施肥)으로 냉해(冷害)가 경감(輕減)되었다. 3. 냉해(冷害)는 통일계품종(統一系品種)이 일반계품종(一般系品種)보다 심(甚)한 경향(傾向)이었고 냉해(冷害)는 불임(不稔), 영화퇴화(穎花退化), 추수불량(抽穗不良) 및 양분흡수(養分吸收) 억제등(抑制等)으로 나타났다. 4. 저온하(低溫下)에서는 질소시용량(窒素施用量)이 많을수록 식물체내(植物體內) 규산함량(珪酸含量)이 유의성(有意性)있게 감소(減少)되었다. 5. 냉해조건하(冷害條件下)에서의 통일계품종(統一系品種)의 질소비료(窒素肥料) 시용적량(施用適量)은 13.6kg/10a으로서 예년(例年)보다 약(約) 10kg/10a 적었으며 수량(收量)도 크게 감소(減少)되었고 감소율(減少率)은 통일계품종(統一系品種)이 일반계품종(一般系品種)보다 심(甚)하였다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2001년도 춘계학술대회 논문집
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• pp.95-99
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• 2001

As a way to use energy effectively, the present study is aimed at investigating the performance characteristics of a Single Effect LiBr/Water Absorption Refrigerator using a low temperature driving heat-source. It was carried out by changing the driving heat-source temperature, the cold water outlet temperature(the refrigeration load), the cooling water inlet temperature, and the weak solution flow rate and this study compares the performance characteristics of refrigerator against the existence and non-existence of the Recirculation of the Weak solution which is used as a method to improve the performance of refrigerator. In case of Recirculation of the weak solution, more improved the Refrigeration Capacity and COP was obtained, and these effects became more larger in the high temperature of driving heat-source and large quantity of solution.

• 대한기계학회논문집B
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• 제23권5호
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• pp.628-636
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• 1999

This work describes the low-resolution spectral modeling of the water vapor, carbon dioxide and their mixtures by applying the weighted-sum-of-gray-gas-gases model (WSGGM) to each narrow band. Proper modeling scheme of gray gas absorption coefficients vs temperature relation is suggested. Comparison between the modeled emissivity calculated from this relation and the 'true' emissivity obtained from the high temperature statistical narrow band parameters is made for a few typical narrow bands. Low resolution spectral intensities from one-dimensional layers are also obtained and examined for uniform, parabolic and boundary layer type temperature profiles using the obtained WSGGM's with several gray gases. The results are compared with the narrow band spectral intensities obtained by a narrow band model-based code with Curtis-Godson approximation. Good agreement is found between them. Data bases including optimized modeling parameters and total and low-resolution spectral weighting factors are developed for water vapor, carbon dioxide and their mixtures. This model and obtained data bases, available from the authors' Internet site, can be appropriately applied to any radiative transfer equation solver.

• 통합자연과학논문집
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• 제3권3호
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• pp.157-161
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• 2010

New low temperature synthesis of germanium nanoparticles obtained from the reaction of germanium tetrachloride and sodium/benzophenonewere developed. These germanium nanoparticles terminated with chloride group were oxidized in air to give hydroxy-terminated germanium nanoparticles. Germanium nanoparticle containing 20(S)-camptothecin (CPT) for a noble drug delivery system were developed. FT-IR spectroscopy was used for the characterization of vibrational absorption for the germanium nanoparticle and oxidized germanium nanoparticles containing camptothecin. Electronic absorption and fluorescence properties were measured with UV-Vis and fluorescence spectrometer. The morphology of oxidized germanium nanoparticles containing camptothecin was investigated by using TEM.

• Bulletin of the Korean Chemical Society
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• 제16권2호
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• pp.126-129
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• 1995

Linear and nonlinear optical properties of CuCl nanocrystals in silica glass have been studied using low temperature absorption, degenerate four wave mixing (DFWM), and time-resolved photoluminescence spectroscopy. Assuming a spherical shape, effective radius of the CuCl quantum dots was estimated to be 2.5 nm, which is obtained from low temperature absorption data. The DFWM experiment was performed in 380-386 nm wavelength region, and the diffracted signal was measured as a function of wavelength with 1.0 nm interval. Time-resolved photoluminescence measurement was also carried out at 77 K to obtain the time response of CuCl nanocrystals. The experimental results on the large third order nonlinear optical of CuCl quantum dots are explained in terms of crystal size and oscillator strength of quantum spheres.