• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1996년도 경북지부 결성 및 추계학술발표회 논문집
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• pp.50-53
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• 1996

This paper reports the experimental results for the determination of the overall partition coefficient of VOCs in unsaturated soil, A chromatographic method was used for the determination of gaseous partition coefficients to natural soil under various water content conditions. The equilibrium vapor pressure of water over saturated salt solution was used to fix the relative humidity of the air and control the water content of the soil systems. The transport behavior was studied for dichloromethane, trichloroethane and dichlorobenzene pollutants, with log octanol-water partition coefficients(log $K_{ow}$ ) which range from 1.25 to 3.39, or water to soil partitioning which varies by 135 times; water solubility constants which vary by 3 times; and vapor pressures which range from 1 to 362 torr. Water content of the soil had a pronounced effect on the effective partition coefficient(between gas and soil + water stationary phase) as well as on the effective dispersion coefficient.

• 설비공학논문집
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• 제3권4호
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• pp.215-221
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• 1991

Laminar film condensation of a saturated vapor in forced flow over a flat plate is analyzed by using integral method. Laminar condensate film is so thin that the inertia and thermal convection terms in liquid flow can be neglected. Approximate solutions for water are presented and well agreed with the similarity solutions over the wide range of physical parameter, Cp1(Ts-Tw)/Pr.hfg. For the strong condensation case, it is found that magnitude of the interfacial shear stress at the liquid-vapor interphase boundary is approximately equal to the momentum transferred by condensation, i.e., ${\tau}_i{\simeq}\dot{m}(U_O-U_i)$.

• 한국연초학회지
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• 제6권1호
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• pp.33-37
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• 1984

The net enthalpy changes for the water desorption of sun-cured tobacco have been studied. In order to compare the values of net enthalpy changes for the samples at the same moisture contents, correlation analyses have been performed. The results are summarizing as followings : 1 . As temperature and water vapor pressure increased, equlibrium moisture content were approaching to the saturated vapor pressure of water. 2. The values of 1nP against the reciprocal of absolute temperature were linear for the water desorption of samples. 3. Multiple regression was analyzed to calculate the values of 1nP at the same moisture content. The significance of $x^2$-test for the multiple regression was 0.5%. 4. The values of net enthalpy changes for Basma were greater than those of Sohyang at the same moisture content.

• International Journal of Aeronautical and Space Sciences
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• 제3권1호
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• pp.9-18
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• 2002

Thermal humidity characteristics were considered theoretically and experimentally. A Simply well-fitted correlation of a saturated vapor pressure-temperature curve of water was introduced based on Antoine equation to make theoretical prediction of relative humidity according to temperature variation. Characteristics of dew point were also examined theoretically and its relation with temperature and humidity was evaluated. The exact mass of water vapor in a specified humidity and temperature condition was estimated to provide useful insight into the idea about how much amount of water corresponds to a specified humidity and temperature condition in a confined system. A simple but well-fitting model of dehumidification process was introduced to anticipate the trend of relative humidity level during GN2(gaseous nitrogen) purge process in a humidity chamber. Well-suitedness of this model was also verified by comparison with experimental data. The overall appearance and specification of two thermal humidity chambers were introduced which were used to perform various thermal humidity tests in order to yield useful data necessary to support validity of theoretical models.

• 대기
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• 제33권5호
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• pp.457-475
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• 2023

Accurately predicting localized heavy rainfall is challenging without high-resolution mesoscale cloud information in the numerical model's initial field, as precipitation intensity and amount vary significantly across regions. In the Korean Peninsula, the radar observation network covers the entire country, providing high-resolution data on hydrometeors which is suitable for data assimilation (DA). During the pre-processing stage, radar reflectivity is classified into hydrometeors (e.g., rain, snow, graupel) using the background temperature field. The mixing ratio of each hydrometeor is converted and inputted into a numerical model. Moreover, assimilating saturated water vapor mixing ratio and decomposing radar radial velocity into a three-dimensional wind vector improves the atmospheric dynamic field. This study presents radar DA experiments using a numerical prediction model to enhance the wind, water vapor, and hydrometeor mixing ratio information. The impact of radar DA on precipitation prediction is analyzed separately for each radar component. Assimilating radial velocity improves the dynamic field, while assimilating hydrometeor mixing ratio reduces the spin-up period in cloud microphysical processes, simulating initial precipitation growth. Assimilating water vapor mixing ratio further captures a moist atmospheric environment, maintaining continuous growth of hydrometeors, resulting in concentrated heavy rainfall. Overall, the radar DA experiment showed a 32.78% improvement in precipitation forecast accuracy compared to experiments without DA across four cases. Further research in related fields is necessary to improve predictions of mesoscale heavy rainfall in South Korea, mitigating its impact on human life and property.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2004년도 동계학술대회 논문집
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• pp.121-121
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• 2004

• 대한설비공학회지:설비저널
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• 제9권1호
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• pp.13-23
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• 1980

파이프의 단면을 투과한 방사선의 물리적 특성을 이용하여 파이프내를 통과하는 포화증기와 화수의 혼합류에서의 기포율 측정을 이론적으로 전개하여 전자계산기로 해를 구하고 이를 모로서 실험에 의하여 입증하였다.

• 한국농림기상학회지
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• 제22권4호
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• pp.299-311
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• 2020

농산촌 지역 단일 집수역인 전남 구례군 간전면 중대리계곡과 경남 하동 악양면에서 각각 6지점과 14지점의 기상관측자료를 수집하여 복잡지형에서의 수증기압 및 상대습도 분포를 분석하였다. 중대리계곡에서는 2014년 12월 19일부터 2015년 11월 23일까지, 악양계곡에서는 2012년 8월 15일부터 2013년 8월 18일까지 가장 고밀도로 측정한 시기의 매시 기온과 습도(지면 위 1.5m)를 이용, 농업기상재해 조기경보시스템에서 사용되고 있는 기존의 수증기압 추정방식과 실제 수증기압을 비교하였다. 관측한 수증기압의 해발고도에 따른 기울기는 시간대(0300, 0600, … 2400 LST)에 따라 변동되었고, 야간일수록 위 아래의 수증기압차가 증대되었다. 지형·지표 조건이 다양한 악양계곡 관측 지점에서는 해발고도 외의 요인으로 인한 수증기압 변이가 지점별로 시간대에 따라 다르게 나타났다. 실제에 더 가까운 수증기압 및 상대습도 추정을 위해, 연구 대상지역의 관측자료로 해발고도 편차 당 수증기압 변화를 조정하는 계수를 도출하였다. 상대습도는 포화수증기압 대비 추정된 수증기압으로 모의하였으며, 조기경보시스템에서 사용된 기존 방법보다 도출된 계수를 활용한 추정방식에서 오차가 더 개선되었음을 확인하였다.

• Journal of Astronomy and Space Sciences
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• 제27권3호
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• pp.231-238
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• 2010

We analyzed global positioning system (GPS)-derived precipitable water vapor (PWV) trends of the Korea Astronomy and Space Science Institute 5 stations (Seoul, Daejeon, Mokpo, Milyang, Sokcho) where Korea Meteorological Administration meteorological data can be obtained at the same place. In the least squares analysis, the GPS PWV time series showed consistent positive trends (0.11 mm/year) over South Korea from 2000 to 2009. The annual increase of GPS PWV was comparable with the 0.17 mm/year and 0.02 mm/year from the National Center for Atmospheric Research Earth Observing Laboratory and Atmospheric InfraRed Sounder, respectively. For seasonal analysis, the increasing tendency was found by 0.05 mm/year, 0.16 mm/year, 0.04 mm/year in spring (March-May), summer (June-August) and winter (December-February), respectively. However, a negative trend (-0.14 mm/year) was seen in autumn (September-November). We examined the relationship between GPS PWV and temperature which is the one of the climatic elements. Two elements trends increased during the same period and the correlation coefficient was about 0.8. Also, we found the temperature rise has increased more GPS PWV and observed a stronger positive trend in summer than in winter. This is characterized by hot humid summer and cold dry winter of Korea climate and depending on the amount of water vapor the air contains at a certain temperature. In addition, it is assumed that GPS PWV positive trend is caused by increasing amount of saturated water vapor due to temperature rise in the Korean Peninsula. In the future, we plan to verify GPS PWV effectiveness as a tool to monitor changes in precipitable water through cause analysis of seasonal trends and indepth/long-term comparative analysis between GPS PWV and other climatic elements.

• 설비공학논문집
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• 제17권11호
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• pp.981-989
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• 2005

In this study, external condensation heat transfer coefficients (HTCs) are measured on a low fin tube and Turbo-C tubes at the saturated vapor temperature of $30^{\circ}C$, $39^{\circ}C$, and $50^{\circ}C$ for R22, R410A, R407C and R134a with the wall subcooled at $3{\~}8^{\circ}C$. The HTCs of all refrigerants decreased as increasing the saturation temperature from $30^{\circ}C$ to $50^{\circ}C$. This trend is due to better thermodynamic properties of the liquid phase at low temperature Beatty and Katz's prediction yielded a $20.0\%$ deviation for the low fin tube data. The heat transfer enhancement factors for the 26 fpi low fin tube and Turbo-C tubes are 4.0${\~}$5.5 and 3.0${\~}$8.1 respectively for the refrigerants tested. Finally the performance of Turbo-C tube is better than that of the low fin tube.