• 통합자연과학논문집
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• 제6권1호
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• pp.12-15
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• 2013

To combine the micro rain radar and microwave radiometer cloud liquid water, we estimate the cloud physical thickness from the difference between the MTSAT-1R cloud top height and cloud base height of visual observation of Daegwallyeong weather station, and the cloud liquid water path of micro rain radar is obtained by multiplying the liquid water content of micro rain radar and the estimated cloud physical thickness. The trend of microwave radiometer liquid water path agrees with that of the micro rain radar during small precipitation. We study these characteristics of micro rain radar and microwave radiometer for small precipitation to obtain the combined cloud water content of micro rain radar and microwave radiometer, constantly operated regardless to the rainfall.

• Archives of Pharmacal Research
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• 제26권10호
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• pp.880-885
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• 2003

Research in this paper focuses on the kinetic evaluation of swelling of the liquid crystalline phases of glyceryl monooleate (GMO). Swelling of the lamellar and cubic liquid crystalline phases of GMO was studied using two in vitro methods, a total immersion method and a Franz cell method. The swelling of the lamellar phase and GMO having 0 %w/w initial water content was temperature dependent. The swelling ratio was greater at $20^{\circ}^C than 37^{\circ}^C$ . The water uptake increased dramatically with decreasing initial water content of the liquid crystalline phases. The swelling rates obtained using the Franz cell method with a moist nylon membrane to mimic buccal drug delivery situation were slower than the total immersion method. The swelling was studied by employing first-order and second-order swelling kinetics. The swelling of the liquid crystalline phases of GMO could be described by second-order swelling kinetics. The initial stage of the swelling (t < 4 h) followed the square root of time relationship, indicating that this model is also suitable for describing the water uptake by the liquid crystalline matrices. These results obtained from the current study demonstrate that the swelling strongly depends on temperature, the initial water content of the liquid crystalline phases and the methodology employed for measuring the swelling of GMO.

• 한국농공학회지
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• 제38권5호
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• pp.116-124
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• 1996

The purpose of The work described in this paper is to clear up the initial moisture content, specific surface, air drying and freezing-thawing process on liquid limit of clayey soils distributed widely at estuary of three main rivers in the west coast. To this end, a series of tests were conducted on clayey soils samples with natural state and treated state. From the test results, the liquid limit was decreased with decrement of initial moisture content, air drying process, and freezing-thawing cycles and increased with increment of specific surface. The specific surface which influenced on the liquid limit is over $25 m^2$m$^2$/g, and their relationships are well formulated. Air drying process is expected to improve the engineering properties of the soils such the pro-water properties were changed to anti-water proper-ties through lowering of water holding as resulted to incline from A-7-5 to A-5 on the soil classificaction plastic chart. The freezing-thawing process decreased 20% of liquid limit, especially under the first cycle of the behavious, as a result of above mentioned reasons, phase change of soil-water system brought the decrement of specific surface and affected to the liquid limit.

• 한국응용과학기술학회지
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• 제28권4호
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• pp.431-437
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• 2011

Transparent liquid crystal gels with high oil content by fatty acid soap were investigated. The solubilization efficiency of the mineral oil was dependent on the process. The process of dropping water part into the solution of oil and surfactant was more efficient than the process of dropping water part into the surfactant solution and after that dropping oil. The fatty acid soap could not solubilize the high oil content, but under the certain range, addition of CDE (Coconut Diethanolamide), Arlacel 165 (Glyceryl Stearate/PEG-100 Stearate) and cetostearyl alcohol helped solubilize the high content oil. Also, the glycerin and water content had influence on the solubilization. Especially, higher oil content gel showed elastic feature.

• 한국지반공학회논문집
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• 제29권11호
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• pp.73-84
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• 2013

사면 내 토사가 붕괴되거나 토석류가 발생하는 경우 파괴면에 작용하는 전단강도는 0에 가깝게 되면서 토사가 비점성 액체와 같이 유동한다. 점성토는 함수비 증가에 따라 그 연경도가 달라지며 액체상태로 바뀌는 액성한계에서 도 약간의 전단강도를 가진다. 본 연구에서는 점성토의 전단강도가 0이 되어 흐름을 유발하는 함수비를 찾고자 하였 다. 카올리나이트, 벤토나이트, 그리고 카올리나이트(50%)+벤토나이트(50%)와 같은 세 종류의 점토에 혼합수로 증류 수, 해수, 또는 미생물용액을 혼합하여 액성한계 상태로 만든 다음 함수비를 단계적으로 증가시키면서 토베인 시험기 를 이용하여 비배수전단강도를 측정하였다. 액성한계와 소성한계에서 비배수전단강도의 범위는 각각 3.6-9.2kPa와 24-45kPa 정도이었다. 한편 측정 결과로부터 비배수전단강도가 급격하게 변화하는 값에 해당하는 함수비를 흐름함수 비(Flow Water content)로 정의하였으며, 비배수전단강도가 0이 될 때의 함수비를 흐름한계(Flow Limit)로 정의하였다. 그리고 흐름한계와 액성한계의 상관관계를 살펴보기 위하여 흐름한계와 액성한계의 차이를 점성지수(Cohesive Index) 로 정의하였다. 또한 흐름한계와 소성한계의 차이를 새로운 소성지수(New Plasticity Index)로 정의하였으며, 흐름한계를 이용하여 새로운 액성지수(New Liquidity Index)도 정의하였다. 흐름한계(Flow Limit)는 액성한계보다 1.5-2배 정도 높은 값을 보였으며, 새로운 소성지수는 기존 소성지수보다 2-5.5배 정도 높았다.

• 대한원격탐사학회지
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• 제14권2호
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• pp.165-174
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• 1998

구름 속의 수액량 분포와 인공강우에 의한 잠재적 증우 가능성을 조사하기 위해 1797년 7월부터 1998년 2월가지 이중채널 마이크로웨이브 레디오메타를 사용하여 안동 지방에서 관측을 실시하였다. 안동 지방의 수액량은 대부분의 시간대에서 0.1mm 이하로 매우 작은 값을 보였다. 계절적 특성을 살펴보면 여름철에 수액량이 가장 풍부하였으며, 봄, 가을, 겨을 순이었다. 수액량의 일변화 양상은 여름철을 제외한 계절에서 12시부터 17시까지 비교적 높은 수액량을 보였으며, 강수량이 많은 여름철에는 수액량의 시간 변동이 심한 것으로 조사되었다 풍향에 따른 수액량의 분포는 소백산맥을 넘어오는 기류인 서풍과 남서풍 계열의 바람에서 수액이 풍부하게 존재하는 것으로 조사되었다. 수평 수액량 플럭스와 연직 강수량의 비인 잠재적 증우 가능량(P$_{en}$)은 대부분 0.5 이하였으며, 계절적으로는 봄철에 0.5, 여름과 가을철에 0.2, 그리고 겨울철에 0.1 이었다. 결과적으로 안동지역에서 인공강우에 의한 최대 증우 가능성은 봄철 서풍계열의 바람에서 높은 것으로 조사되었다. .

• 한국분무공학회지
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• 제6권1호
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• pp.18-24
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• 2001

Liquid fossil fuel contaminated by water can cause trouble in the combustion processes and affect the endurance of a combustion system. Using an optical sensor to monitor the water content instantaneously in a fuel pipeline is an effective means of controlling the fuel quality in a combustion system. In two component liquid flows of oil and water, the flow pattern and characteristics of water droplets are changed with various flow conditions. Additionally, the light scattering of the optical sensor measuring the water content is also dependent on the flow patterns and droplet characteristics. Therefore, it is important to investigate the detailed behavior of water droplets in the pipeline of the fuel transportation system. In this study, the flow patterns and characteristics of water droplets in the turbulent pipe flow of two component liquids of gasoline and water were investigated using optical measurements. The dispersion of water droplets in the gasoline flow was visualized, and the size and velocity distributions of water droplets were simultaneously measured by the phase Doppler technique. The Reynolds number of the gasoline pipe flow varied in the range of $4{\times}10^{4}\;to\;1{\times}10^{3}$, and the water content varied in the range of 50 ppm to 300 ppm. The water droplets were spherical and dispersed homogeneously in all variables of this experiment. The velocity of water droplets was not dependent on the droplet size and the mean velocity of droplets was equal to that of the gasoline flow. The mean diameter of water droplets decreased and the number density increased with the Reynolds number of the gasoline flow.

• 한국지반공학회논문집
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• 제32권10호
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• pp.5-15
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• 2016

본 연구에서는 소형콘의 관입저항력을 이용한 점토의 액성한계를 측정하기 위하여 카올리나이트 점토와 벤토나이트 점토의 비율을 다양하게 혼합한 점토흙에 대하여 함수비와 소형콘의 관입저항력을 조사하고 기존의 동적(Casagrande 시험법) 및 정적(Fall cone 시험법) 액성한계 시험결과와 직접 비교하였다. 비교결과 다양한 점토흙의 함수비에 따른 관입저항력 관계곡선에서 변곡점이 형성된다는 것을 파악하였으며 이 때의 함수비가 정적액성한계(Fall cone)시험법에 의한 액성한계 값과 매우 유사함을 파악하였다. 변곡점이 형성된 점에서의 소형콘의 관입저항력은 약 0.2kPa로 나타났으며 이 때 의 함수비가 점토흙의 액성한계를 나타낸다는 것을 확인하였다. 이와 같은 연구결과를 토대로 향후 점토의 액성한계를 파악하는데 본 연구에서 조사된 0.2kPa의 소형콘의 관입저항력이 유용한 지표가 될 수 있다는 사실을 파악하였다. 또한 소형콘의 관입저항력을 이용한 액성한계 시험법을 제시하였다.

• 한국환경보건학회지
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• 제19권2호
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• pp.55-60
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• 1993

This study was performed to investigate the effect of washing with water and detergent on the vitamin C content in strawberry and perilla leaf. Vitamin C was extracted with the solution of metaphosphoric acid and quantitated by high performance liquid chromatograph (HPLC). There was no significant difference of vitamin C content between the washing with distilled water and tap water. Three available detergents reduced the vitamin C content of samples to 92.5%, 92.2% and 78.5%, respectively. The content of vitamin C in samples was decreased by increasing the concentration of detergent and washing time.

• 청정기술
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• 제8권2호
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• pp.67-76
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• 2002

Dewatered sludge of 400,000t/y from water treatment plants in Korea is being disposed through landfill and ocean dumping. However, the disposal is posing more and more serious environmental problems at the same time not only because of landfill site shortage in municipal suburbs, but because of the concern it will contaminate the oceans. In this study, the research on utilizing the sludge dried by flash dryer as covering soil in the landfill sites was carried out to solve these problems on environmental affinity. Both dewatered and dried sludge were exposed to the natural condition and observed according to the atmospheric changes. An experiment of soil engineering characteristics of the dried sludge and tests on mixed sludge(silty sandy soil : dried sludge = 10:90 ~ 30:70) such as particle size distribution, liquid and plastic limit, moisture content, specific gravity and compaction test were carried out. According to the compaction test, the compaction was confirmed as the optimum water content ratio was observed in the condition of SM-silty sand of particle size distribution, NP of liquid and plastic limit, 101.4% of moisture content, 2.04~2.12 of specific gravity. The results showed that dried sludges mixed with at least 30% of natural soil could be used as daily covering soil in the landfill sites.