• 대한원격탐사학회지
• /
• 제23권1호
• /
• pp.7-14
• /
• 2007

Atmospheric correction is one of critical procedures to extract quantitative information related to biophysical variables from hyperspectral imagery. Most atmospheric correction algorithms developed for hyperspectral data have been based upon atmospheric radiative transfer (RT) codes, such as MODTRAN. Because of the difficulty in acquisition of atmospheric data at the time of image capture, the complexity of RT model, and large volume of hyperspectral data, atmospheric correction can be very difficult and time-consuming processing. In this study, we attempted to develop an efficient method for the atmospheric correction of EO-1 Hyperion data. This method uses the pre-calculated look-up-table (LUT) for fast and simple processing. The pre-calculated LUT was generated by successive running of MODTRAN model with several input parameters related to solar and sensor geometry, radiometric specification of sensor, and atmospheric condition. Atmospheric water vapour contents image was generated directly from a few absorption bands of Hyperion data themselves and used one of input parameters. This new atmospheric correction method was tested on the Hyperion data acquired on June 3, 2001 over Seoul area. Reflectance spectra of several known targets corresponded with the typical pattern of spectral reflectance on the atmospherically corrected Hyperion image, although further improvement to reduce sensor noise is necessary.

• 수산해양기술연구
• /
• 제59권2호
• /
• pp.110-116
• /
• 2023

In this study, samples of sea anchor canopy cloth mainly used in Korean jigging fishing vessels were collected and tested for performance evaluation. The canopy cloth of sea anchor is a basic element of form composition that is known to have the greatest influence on anchor performance. In order to evaluate the performance of sea anchor canopy cloth, five types of samples were tested for new metric count, tensile strength, water vapour transmission rate and drying speed according to the national standard (KS), and some correlations were identified. As a result of the test, the new metric count of cloths was 335.5-443.4 denier in warp and 217-447.6 denier in weft, and the minimum tensile strength was 860 N in warp direction and 430 N in weft direction. The apparent number and tensile strength of cloth were proportional, the water vapour transmission rate of the sample was 206.8 g/m²h, and the drying speed was 90-100 min. This study partially confirmed the performance evaluation based on speculation by the standard test method, and further research is needed on the clear relationship between the research results and the performance of the sea anchor.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2005년도 춘계 학술대회
• /
• pp.172-181
• /
• 2005

국내 원전에서 공기 중 삼중수소 농도를 평가하기 위해 사용하는 삼중수소 버블러의 포집효율에 대하여 고찰하였다. 수증기 형태인 공기 중 삼중수소는 기포가 물을 통과하는 동안 평형농도에 도달하게 된다. 많은 양의 기체시료를 통과시킬 경우 포집수의 삼중수소 농도가 높아지고 포집수가 감소하거나 증가하는 현상이 발생하여 포집효율에 영향을 미치게 된다. 이러한 영향을 고려한 포집수의 예측농도는 실측값과 잘 맞았다. 통상적인 방식과 같이 초기 포집수량을 이용하여 삼중 수소 포집량을 평가할 경우 기체시료의 상대습도가 0.5보다 높으면 포집효율은 1보다 낮아지고 상대습도가 0.5보다 낮으면 포집효율은 1보다 높아진다. 상대습도가 0.5가 아니더라도 $\frac{포화수증기량\times기체통과량}{포집수량}$을 작게 하면 포집효율을 1에 가깝게 유지할 수 있다.

• Korean Membrane Journal
• /
• 제6권1호
• /
• pp.10-15
• /
• 2004

We developed a water-selective ceramic composite membrane for use as a dehydration membrane reactor for dimethylether (DME) synthesis from methanol. The membranes were modified on the porous stainless steel support by the sol-gel method accompanied by a suction process. The improved membrane modification process was effective in increasing the vapour permselectivity by removal of defects and pinholes. The optimized alumina/silica composite membrane exhibited a water permeance of 1.14${\times}$10$^{-7}$ mol/$m^2$.sec.Pa and a water/methanol selectivity of 8.4 at permeation temperature of 25$0^{\circ}C$. The catalytic reaction for DME synthesis from methanol using the membrane was performed at 23$0^{\circ}C$, and the reaction conversion was compared with that of the conventional fixed-bed reactor. The reaction conversion of the membrane reactor was much higher than that of the conventional fixed-bed reactor. The reaction conversion of the membrane reactor and the conventional fixed-bed reactor was 82.5 and 68.0%, respectively. This improvement of reaction efficiency can last if the water vapour produced in the reaction zone is removed continuously.

• 한국산림과학회지
• /
• 제85권2호
• /
• pp.210-224
• /
• 1996

SLODSVAT 모델은 (1)식생의 환경 조건과 생태 생리학적 특징에 의해 결정된 두개 수관층에서의 복사, 수분증발, 열, 이산화탄소 및 바람(momentum) 등의 이동과, (2)식물의 뿌리, 줄기, 잎으로 이어지는 수분의 흡수와 저장 및, (3)수관에 의한 강우의 차단, 그리고 토양에 의한 강우의 저장과 유하 등을 Simulation한 상호관련된 몇 개의 하위 모델들로 구성되어 있다. 본 연구에서는 독일 중부에 위치한 Solling지방의 독일가문비림(Picea abies L Karst)을 대상으로 기후 관측 결과와 모델링에 의한 결과를 서로 비교해 본 바, SLODSVAT는 서로 다른 환경 조건하에서 수분증발과 열 흐름의 계절적 변화 뿐만 아니라 일변화도 자연적 과정에 맞게 적절히 설명할 수 있음을 알 수 있었고, 또한 대기, 임관 및 토양 구조에 대한 기상학적, 식물학적, 수문학적 자료들이 유능하다면 독일가문비림 생태계에 대한 증산과 증발산의 비를 평가하고 예측함이 가능함을 알 수 있었다.

• Membrane and Water Treatment
• /
• 제1권1호
• /
• pp.1-12
• /
• 2010

Membrane distillation process was used for purification of pre-treated natural water (tap water). The rejection of inorganic and organic compounds in this process was investigated. The obtained rejection of inorganic solutes was closed to 100%, but the volatile organic compounds (VOCs) diffused through the membrane together with water vapour. The content of trihalomethanes (THMs) in the obtained distillate was two-three fold higher than that in the feed, therefore, the rejection of the total organic compounds present in the tap water was reduced to a level of 98%. The intensive membranes scaling was observed during the water separation. The morphology and composition of the fouling layer was studied using scanning electron microscopy coupled with energy dispersion spectrometry. The influence of thermal water pre-treatment performed in a heat exchanger followed by filtration on the MD process effectiveness was evaluated. This procedure caused that significantly smaller amounts of $CaCO_3$ crystallites were deposited on the membrane surface, and a high permeate flux was maintained over a period of 160 h.

• KIEAE Journal
• /
• 제14권3호
• /
• pp.105-109
• /
• 2014

The recent rising living standards, environment-friendly, well-being and health aspects of life in the basic gratification, as well as the desire for a pleasant environment emotionally environmentally friendly way of external space or industrial interest in the indoor environment, the manifestation. In particular, the biggest problem of the indoor environment has been emerged as a Sick House Syndrome indoor space that is provided to the building materials, and the impact on the domestic and the indoor environment, and clean the house in a health standards are specified as laws. The performance rating and the various materials to create environmentally-friendly standards for building materials. The more detail, Porous clay material, toxic substances released by applying the high humidity and the water itself, and to absorb the moisture, if the emissions, without a separate device, to maintain a comfortable indoor environment and at the same time, one of the causes of Sick House Syndrome breaking down harmful substances to absorb a comfortable indoor environment to maintain an environmentally-friendly building interior material studies. It is aimed at the development to multi-functional high performance eco-friendly construction materials, rather than through one feature performance, identify key features for national and international eco-friendly building materials can exert Water Vapour Adsorption raw, decomposed materials for the application and selection.

• 한국결정학회지
• /
• 제12권4호
• /
• pp.216-221
• /
• 2001

채석장 및 서재 가공장에서 폐기되는 미립의 분말의 석분 슬러지를 활용하고자 수영양생법으로 인조 석판재를 제조하였다. 석분 슬러지의 주성분은 석영 및 알루이나로서 여기에소석회 및 규사를 첨가하여 증기압, 수열 반응시간, 소석회의 첨가량 등이 인조석판재의 강도 및 비중에 미치는 영향을 조사하여 수열양샡법을 적용한 인조석재 제조공정을 확립하고자 하였다. 석분 슬러지 70%, 소석회 20% 및 규사 10%에 수분 10% 비율로 혼합한 후 200kg/㎠의 압력으로 성형하여 증기압이 20kg/㎠인 조건으로 3시간 동안 반응시켜 제조한 인조석재는 압축강동 614kg/㎠흡수율 0.48%, 겉보기 비중 1.88인 물성을 나타내었다. 또한 각종 산화물계 안료의 첨가에 의하여 다양한 색상과 문양을 보유한 인조석재의 제조가 가능하였다.

• 한국환경보건학회지
• /
• 제22권3호
• /
• pp.116-122
• /
• 1996

This study has been focused on the applicability of microwave treatment of soil contaminated by volitile organic chemicals. Substrates studied were sand and sandy soil. These substrates were impregnated with toluene, tetrachloroethylene, o-xylene and p-dichlorobenzene. The microwave treatment was conducted in a modified domestic microwave oven: 2450 MHz, 700 W. The sandy soil temperature added water went up rapidly to about 130$\circ$C for 4 minutes. And then, the temperature appeared to plateau out. A series of tests were performed to depict the effectiveness of microwave treatment technique to organic contaminants from soils. Removal efficiencies in sandy soil and sand were increased with increasing water content and exposure time. Microwave radiation penetrates the soil and heats water throughout the matrix. Therefore, addition of a certain amount of water to the contaminated soil can efficiently enhance the ability of the soil to absorb microwave energy and promote the evaporation of the volitile contaminants. And the vapour pressure of impregnated organic contaminants becomes lower. the removal efficiency becomes poor.

• 한국농공학회지
• /
• 제43권6호
• /
• pp.103-112
• /
• 2001

The development of infrared thermometry has led many researchers to use plant temperatures, and specifically the temperature of the crop canopy in the field, for estimating the water stress of a crop. The purpose of this study was to evaluate the role of leaf temperature in irrigation scheduling. An experiment was carried out in a greenhouse with chinese cabbage. Leaf temperature was measured with infrared thermometry and evapotranspiration of the crop was measured by lysimeters. Influence of the difference between leaf temperature and air temperature on crop evapotranspiration was evaluated under varying water stress condition. A further objective was to evaluate the effect of other climatic variables on the relationship between evapotranspiration and temperature difference between leaf and air. A statistical model for estimating evapotranspiration using the temperature difference, relative humidity. and radiation was developed and tested. Crop water stress index was calculated using vapour pressure deficit and the temperature difference. Relations between the crop water stress index and crop evapotranspiration was tested. The index was closely related with evapotranspiration.