• Progress in Medical Physics
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• v.9 no.2
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• pp.115-121
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• 1998

In this paper, basic study of diagnostic device development for early detection of cancer, we present the optical property measurements of 12 histologically classified biological tissue and blood specimens in order to determine whether significant optical contrast exists for detection of disease(cancer). In vitro, optical properties of each 630nm, 660nm, 780n, 880nm and 940nm shows consistent changes in effective absorbtion coefficients, ${\mu}$$\_$${\alpha}$/ with tissue classification of pig an chicken and human blood according to the 27.3%, 35.4%, 45.6% and 59.1% of HCT. We found differences in optical properties at each of specific wavelengths and histologically classified biological tissue.

• Journal of the Korean Society of Safety
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• v.7 no.2
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• pp.63-70
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• 1992

The aim of this research is to obtain a basic quantitative understanding of the effect of a noncondensable gas on the absorption of water vapor by a $H_2O$ / LiBr combination with n-octanol as the surfactant. Nonflowing aqueous solutions of LiBr (40,45,50 mass％) were exposed to saturated water vapor following the addition of an n-octanol sufactant (0.01 and 0.6 mass％). A small amount of a noncondensable gas (air) was allowed into the absorber (0.03 volume％) and its effect was analyzed by measuring the amount of water vapor absorbed. This study will aid to predict the performance of heat pump and safety operating condition when the noncondensable gas is not allowed in the absorber The results indicate that, in the presence of small amounts of a noncondensable gas, vapor absorption enhancement ratios are less than half o( those obtained under the same experimental conditions when a noncondensable gas is not present (1). The presence of a noncondensable gas causes the partial vapor pressure of air to increase at the vapor / liquid interface, which results in an instability of vapor absorption rate nd. hence, in an inhibition of interfacial disturbance.

• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.17-24
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• 2006

최근에 에너지절약 차원에서 종래의 공조방식을 대신할 새로운 냉난방시스템 개발이 요구되고 있는데, 본 논문에서는 태양열 집열기를 이용하는 데시컨트 시스템 중 제습역할을 실질적으로 담당하는 제습기의 충진층 부분에서의 열 및 물질전달에 관한 일련의 해석 결과를 발표하고 있다. 제습과정에서 액체흡수제는 충진층에서 열 뿐만 아니라 물질전달을 수반하게 되는데, 이 결과 건물에 냉방 및 난방효과를 가져다 준다. 따라서 이 충진층의 최적 설계가시스템의 효율을 극대화하기 위해서는 무엇보다도 중요한데, 이를 위해서는 충진층에서의 열 및 물질전달 양상을 규명하여야 한다. 따라서 금번 실험에서는 공기와 액체흡수제와의 접촉면적을 넓히기 위해서 충진재로써 3cm(직경) ${\times}$ 3cm(높이)인 시판중인 플라스틱 재질을 사용하고, 실질적으로 40cm(너비)${\sim}$40cm(깊이)${\times}$40cm(높이)의 충진층을 직접 제작하여 실험을 행하였다. 그 결과, 공기측 열 및 물질전달 계수는 공기 온도와 밀접한 관계를 갖고 있으며, 또한 물질전달계수는 열전달계수와 같은 경향을 보이고 있음을 알 수 있었다.

• Journal of Sensor Science and Technology
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• v.3 no.3
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• pp.36-44
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• 1994

A fiber-optic temperature sensor utilizing InP as a sensing medium was implemented and tested to determine the dependance of the optical characteristics of InP on physical parameters for the use as design parameters in this type of sensors. The optical absorption coefficient of InP has been determined through the experimental measurement of the fundamental optical absorption characteristics at various temperature points. The transmission characteristics of light source at three temperature points($249^{\circ}K$, $298^{\circ}K$, $369^{\circ}K$) are computed from the optical absorption coefficient for a fixed length of InP. A series of measurement concluded that optical absorption edge moves to longer wavelength region at a speed of 0.42 nm / $^{\circ}K$ as the specimen gets hotter, and that increasing the thickness of the InP sensing layer shifts power density curve to lower temperature region.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.15-22
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• 1999

Polymeric meterials that are used for noise and vibration damper in wood/polymer/wood sandwich composites, must have a high loss factor(tan ${\delta}$), and at the same time the storage modulus(E) of $5{\times}10^7$ to $10^9$ dyne/$cm^2$ must withstand over a wide temperature and frequency ranges. In this study, the series of epoxy resinlpolyacrylate interpenetrating polymer networks(IPNs) were synthesized by simultaneous polymerization. Their dynamic tensile properties were measured at 110Hz using Rheovibron instrument. Composite damping factor(tan ${\delta}_c$) and dynamic bending modulus($E_c,\;E_^{\prime\prime}c$) of wood/polymer/wood sandwich composites were measured at 110Hz using a Rheovibron in bending mode of vibration. These dynamic tensile studies indicated that cured epoxy resin/polyacrylates IPNs were semicompatible in the sense that both the shifting of T($E^{\prime\prime}_{max}$) or T(tan ${\delta}_{max}$) and the broadening of glass transition temperature range were observed. Especially, the cured Epikote871/P(n-BMA) IPNs of composition 70/30 to 50/50 showed a relatively high tan a and appropriate E' value over a wide temperature range; consequently the tan a e curves of wood/IPNs/wood sandwich composites was broadened over a wide temperature range.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.09a
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• pp.23-38
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• 1995

고분자막에 의한 기체분리는 심냉분리법, 흡수법, 흡착법등에 비하여 에너지가 절약되며 장치가 간결하고 운전비용이 낮은 이점 때문에 여러가지 기체혼합물에 대하여 여러가지 목적으로 응용되기에 이르렀다. O$_{2}$/N$_{2}$ 분리막으로 요구되는 기본특성은 1) 높은 O$_{2}$ 투과성 2) 높은 O$_{2}$ 선택성 3) 막 형성에 충분한 기계적 강도 4) 열, 화학적으로 안정성이 있어야 한다. 그런데 투과계수 P$_{O_(2)}$와 투과선택도 P$_{O_(2)}$/P$_{N_(2)}$ 관계 Fig.2 에서 보는 바와 샅이 대체로 투과선택성은 상반관계에 있어서 polyimide는 높은 선택성을 나타내고 기계적 강도가 좋고 높은 열에 대하여 안정하기 때문에 일단 막재료로 양호한 조건을 갖추고 있으나 투과계수가 크지 않아 선택도를 크게 감소시키지 않으면서 투과계수를 향성시키려는 노력이 경주되고 있다. 따라서 polyimide의 화학구조와 투과계수, 투과선택도의 관계를 고찰하는 것은 대단히 중요하다. 특히 최근에는 polyimide의 화학구조를 계통적으로 변화 시켜가면서 구조와 투과특성을 고찰한 연구가 많으며, 이러한 연구를 총망라하여 화학구조와 투과특성을 고찰한 훌륭한 총설들이 발표되어왔다. Fig.3에는 지금까지 연구된 중요한 polyimide를 형성하는 dianhydride와 diamine의 구조식을 표시하였으며 이들 구조의 변화에 의하여 기체투과계수와 투과선택도가 어떤 영향을 받는지 고찰하고자 한다.

• Journal of Energy Engineering
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• v.10 no.1
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• pp.63-70
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• 2001

재료의 열확산계수를 비접촉적인 방법으로 구하기 위하여 광열편향법에 대한 3차원 모델을 해석하였다. 이 방법은 가열빔이 재료에 광학적으로 흡수될 때 검사빔의 초기궤적이 시편과 시편주의 매질의 온도상승으로 인하여 나타나는 굴절지수의 구배에 의하여 검사빔이 편향되는 원리를 이용하는 것이다. 기존의 연구에서는 주로 가열빔과 검사빔의 상대거리를 변화시키면서 편향의 위상각을 측정하여 열확산계수를 결정하였다. 하지만 본 연구에서는 고정된 상대거리에서 가열빔의 변조주파수를 변화시키면서 편향의 위상각을 계산하여 열확산계수를 구할 수 있는 관계식을 제시하였다. 본 연구에서 제시한 열확산계수 결정 방법은 다른 방법에 비하여 실험과 해석이 간단하고 비교적 측정하기가 어려운 상대거리에 영향을 받지 않는 방법이다.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.184-188
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• 1997

To investigate the absorption and transfer factor(TF) of Sr-85 by rice(Oryza sativa L.), experiments were carried out through pot cultivations on a sandy-loam soil treated 74 and 222Bq per gram of soil in a plastic film house. Sr-85 absorption rates of Ilpoombyeo, late maturing variety and Odaebyeo, early maturing variety, at harvesting stage, were 0.39-0.43% and 0.66-0.73%, respectively. Sr-85 absorption rates of Odaebyeo were about 1.5 times higher than those of Ilpoombyeo. Ratios of Sr-85 radiation and Sr-85 concentration in brown rice were much lower compared with those in straw and husk. Sr-85 concentrations in each part of Odaebyeo were remarkably higher than those of Ilpoombyeo. Transfer factor of Sr-85 from soil to plant ranged from 0.037 of brown rice to 4.13 of rice straw at harvesting stage. The order of the Sr-85 transfer factor in plant parts was straw>husk>brown rice. Sr-85 concentrations treated in soil had no effect on the growth and yield of rice.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.77-86
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• 1999

Partitioning of two hydrophobic organic compounds (HOCs), phenanthrene and naphthalene, to kaolinite and sorbed surfactants was studied to evaluate the feasibility of surfactant-enhanced remediation (SER) of contaminated subsurface systems. Sorbed surfactant partition coefficients. $K_ss$, showed a strong dependence on the surfactant sorption isotherms at low sorbed surfactant levels $K_ss$ values were at their highest and then decreased with increasing surfactant sorption densities. $K_ss$ values for SDS were always larger than corresponding $K_mic$values. For Tween 80, however. $K_ss$ values $K_mic$ were higher than $K_mic$ values only at the lower sorbed surfactant densities. HOC distribution between immobile and mobile phases varied with surfactant dose distribution coefficients increased initially with increasing surfactant concentrations and then decreased at higher doses. This observation shows directly the competition between sorbed and micellar surfactants for HOC partitioning. Overall results of this study demonstrate that surfactant sorption to the solid phase can lead to increases in HOC retardation in some SER applications. Therefore, before an SER process is selected, appropriate consideration of surfactant sorption and HOC partitioning to immobile versus mobile phases pertinent to a specific subsurface system must be contemplated.

• The Journal of Engineering Geology
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• v.28 no.1
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• pp.25-34
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• 2018

The physical properties and unsaturated characteristics of acid sulfate soils were investigated and analyzed. As the results of measuring physical properties of the acid sulfate soils obtained around the Ilkwang mine area, the dry unit weight is $1.246t/m^3$ and this soil is classified into the silty sand (SM) by USCS. Soil Water Characteristics Curves (SWCC) of the drying and wetting paths were measured by the automated SWCC apparatus. Also, Hydraulic Conductivity Functions (HCF) of the drying and wetting paths were estimated by the van Geunchten (1980) model which is the most well-known parameter estimation method. The hydraulic conductivity of acid sulfate soils in the dry path was continuously decreased with increasing the matric suction. However, the hydraulic conductivity in the wetting path was decreased relatively small with increasing matric suction and decreased suddenly just before water entry value of matric suction. Meanwhile, the hysteresis phenomenon was occurred in SWCCs and HCFs during the drying and wetting paths.