• 한국결정성장학회지
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• 제15권3호
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• pp.114-119
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• 2005

This study has been carried out with the eight HPHT processed NOUV diamonds - two yellow, two yellowish green, two green and two orangy yellow color stones. The gemological properties of these diamonds included a highly saturated body color, graphitized fractures around the girdles, tension cracks around crystalline inclusions, long-wave UV with medium yellowish green to a very strong yellowish green luminescence, and short-wave UV with faint yellowish green to a strong yellowish green luminescence. Distinctive features of spectroscopic properties include absorption peaks at 415 nm and 503 nm a strong absorption band at $460{\sim}480nm$ and a H2 center at 986nm. Infrared spectra showed an absorption peak at $1344cm^{-1}$ (C center), which is the characteristics related to single substitutional nitrogen.

• 대한기계학회논문집B
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• 제32권9호
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• pp.669-675
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• 2008

The objectives of this paper are to examine the effect of nano-particles on the pool type absorption heat transfer enhancement and to find the optimal conditions to design a highly effective compact absorber for ammonia/water absorption system. The effect of $Al_2O_3$ nano-particles and carbon nanotube(CNT) on the absorption performance is studied experimentally. The experimental ranges of the key parameters are 20% of ammonia concentration, $0{\sim}0.08\;vol%$ (volume fraction) of CNT particles, and $0{\sim}0.06 \;vol%$ of $Al_2O_3$ nano-particles. For the ammonia/water nanofluids, the heat transfer rate and absorption rate with 0.02 vol% $Al_2O_3$ nano-particles were found to be 29% and 18% higher than those without nano-particles, respectively. It is recommended that the concentration of 0.02 vol% of $Al_2O_3$ nano-particles be the best candidate for ammonia/water absorption performance enhancement.

• 설비공학논문집
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• 제3권4호
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• pp.263-275
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• 1991

Studies on the annual performance of three different type of solar-absorption heat pump system (parallel type, series type, and generator type) are carried out by using the computer simulation. These include the calculation of solar energy from the solar collector, and the revision of computer package, developed by Oak Ridge National Laboratory, to predict the annual performance. Finally using weather data and load conditions, the annual performance are obtained. Results show that the annual operating costs of three solar-absorption heat pump systems are almost same values and 44% lower than that of the pure absorption heat pump system. The total annual input energys of solar-absorption heat pump systems are also about 44% lower than that of the pure absorption heat pump. The nominal size of the solar-absorption heat pump systems can be reduced to a value of 55% that of the pure absorption heat pump that would normally be specified under identical conditions.

• International Journal of Air-Conditioning and Refrigeration
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• 제14권4호
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• pp.131-137
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• 2006

The absorber in which heat and mass transfer phenomena occur simultaneously is one of the most critical components in the absorption system. It has the most significant influence on the performance and the size of the absorption system. During the absorption process, heat and mass transfer resistances exist in both liquid and vapor regions, so that the heat transfer mode should be carefully selected to reduce them. The objective of this paper is to review the previous papers analysing mathematical models of simultaneous heat and mass transfer phenomena during the absorption process. The most conventional working fluids ($H_2O$LiBr and $NH_3/H_2O$) are considered and the most common absorption modes (falling film and bubble mode) are dealt with in this review.

• 생물환경조절학회지
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• 제14권3호
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• pp.196-202
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• 2005

본 연구는 상토의 보수성 증가를 위하여 혼합되는 acrylamide 계통 고흡수성 수지인 Stocksorb C(STSB)의 수분 흡수 특성, 수분 흡수에 영향을 미치는 각종 무기염의 종류 및 농도, STSB가 침지된 외부용액속의 무기염 농도 변화를 구명하고자 수행하였다. STSB의 수분 흡수량은 증류수에 침지한 경우 약 180 $mL{\cdot}g^{-1}$였다. 1가의 양이온을 포함한 염인 $KH_2PO_4,\;KNO_3$ 또는 $(NH_4)_2SO_4$를 용해시킨 용액의 농도가 높아질수록 흡수량이 저하되었으나 세 종류 양이온의 종류에 따른 차이는 크지 않았다. $Ca(NO_3)_2{\cdot}4H_2O$ 다양한 농도로 용해시킨 용액 속에 STSB를 침지시킨 경우 수분흡수능 저하가 심하여 20 $meq{\cdot}L^{-1}Ca(NO_3)_2{\cdot}4H_2O$ 용액에서 약 25 $mL{\cdot}g^{-1}$ 수분을 흡수하였다. $Mg(NO_3)_2{\cdot}6H_2O$나 $MgSO_4{\cdot}7H_2O$를 용해시킨 용액의 농도가 높아질수록 수분 흡수량이 심하게 저하하였고, 1가의 양이온이 포함된 염을 용해시킨 용액에서보다 그 정도가 심하였다. 그러나 요소의 농도를 증가시킨 용액에서의 수분 흡수량은 저하되지 않았다. 침지전 Hoagland용액의 농도가 높거나, 침지시간이 길어질수록 STSB를 침지시킨 용액에서의 $K^+$및 $NH_4^+-N$의 농도가 점차 높아졌다. Hoagland 용액의 희석배수와 무관하게 침지시간이 길어질수록 외부용액의 $NO_3^--N,\;H_2PO_4^-$ 및 $SO_4^{-2}$ 농도가 약간 상승하였고, 24시간 경과 후 각각 5,300, 250 및 1,500 $mg{\cdot}L^{-1}$ 농도로 분석되었다.

• 한국식품과학회지
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• 제30권3호
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• pp.557-561
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• 1998

본 연구에서는 산성(pH 2.0, 3.0), 중성(pH 7.0) 및 알칼리성(pH 10.0, 12.0)영역에서 각각 추출된 SPI들의 기능성을 상호비교하였다. pH 3.0에서 추출된 SPI의 단백질함량은 93.31%로 최고값을, pH 7.0에서 추출된 SPI의 단백질함량은 73.93%로 최소값을 나타내었다. pH 3.0에서 추출된 SPI의 추출수율은 0.36%로 최소값을, pH 12.0에서 추출된 SPI의 추출수율은 47.54%로 최고값을 나타내었다. SPI의 기능성(용해도, 수분흡수력, 유지흡수력, 기포형성력, 기포안정성, 유화형성력 및 겔형성력)은 대두단백질 추출시 추출용액의 pH에 의해 크게 좌우되었다. pH 2.0과 3.0에서 추출된 SPI의 용해도는 산성영역에서 크게 나타났고 pH 3.0과 7.0에서 추출된 SPI는 중성 영역에서 높은 용해도를 보였으나 pH 2.0, 3.0, 7.0, 10.0 및 12.0에서 추출된 SPI는 모두 알칼리성 영역(pH 9.0-10.0)에서 높은 용해도를 나타내었다. pH 2.0과 pH 12.0에서 추출된 SPI의 수분흡수력, 유지흡수력, 기포형성력 및 기포안정성은 다른 pH에서 추출된 SPI보다 크게 나타났으나 유화력의 경우 추출용액의 pH가 증가할수록 유화력이 증가하였다.

• 한국광학회지
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• 제15권2호
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• pp.177-182
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• 2004

우리는 외부공진분광법을 이용하여 $^{13}$C$_2$H$_2$ 분자의 회전-진동전이의 V$_1$＋V$_3$ 밴드 P(16)전이선의 포화흡수신호를 관측하고, 이 포화 흡수 스펙트럼을 이용하여 1550 nm 영역에서 반도체 레이저 주파수 안정화를 수행하였다. 측정된 포화흡수 스펙트럼의 크기는 선형 흡수에 대해서 약 7%이고, 선폭은 약 1.8 MHz로 측정되었다. 반도체 레이저 주파수를 $^{13}$C$_2$H$_2$ 분자P(16) 전이선에 안정화했을 때 안정화된 레이저의 상대주파수 흔들림은 게이트 시간 0.1 s에서 약 $\pm$20 KHz로 측정되었다.

• 한국소음진동공학회논문집
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• 제17권3호
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• pp.201-206
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• 2007

It is important to consider the sound absorption characteristics of building interior decoration materials when we design a building and simulate acoustics in a room. The purpose of this study is to accumulate acoustic data on building interior decoration materials and give a basic data for improving the sound absorption performance by testing the sound absorption coefficients of 9 types of ceiling materials, 14 types of wall papers and 20 types of floor papers.

• 대한기계학회논문집B
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• 제26권9호
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• pp.1241-1248
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• 2002

Performance extension of the absorption refrigerator with LiBr solution is often faced to operate very close to the crystallization limit. Especially in the development of an air-cooled cycle, the crystallization of working solution in the system is a very difficult problem to overcome. This paper describes the cycle of hot water driven absorption system using a new working absorption solution instead of LiBr solution to improve the efficiency. In this study, we found out the characteristics of new working absorption solution through the cycle simulation and compared LiBr solution to evaluate. The effect of cooling water temperature, weak solution flow rate, hot water temperature and hot water flow rate were also examined. The COP is increased 22% higher in the case of LiBr＋Li1＋LiC1＋LiNO$_3$＋$H_2O$, 2% LiBr＋HO(CH$_2$)$_3$OH＋$H_2O$ than that of LiBr solution for the same operation condition.

• Journal of the Optical Society of Korea
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• 제8권1호
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• pp.1-5
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• 2004

Using the external cavity spectroscopy method, we have observed the saturated absorption spectrum of the P(16) line of the v$_1$+v$_3$ band of $^{13}C$_2$H$_2$$. The frequency of a laser has been stabilized to the saturated absorption spectrum. The relative contrast of the saturation spectrum is about 7% with respect to the linear absorption and the linewidth is about 1.8 MHz. The frequency fluctuation of the stabilized LD is about $\pm$ 20 KHz for a sampling time of 100 ms.