• 제목/요약/키워드: Water movement

검색결과 1,122건 처리시간 0.032초

전동식 워터펌프 개발 (Electric Water pump Development)

  • 정세영;곽중희;박범용;정우진
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 추계학술대회 논문집
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    • pp.217-220
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    • 2007
  • The purpose of study is a development of the high reliance electric driven water-pump that fuction is forcing the movement of water using basic design, proto sample and test at the cooling system. It was important to supply a coolant quickly and accurately for the requirement of flow rate at the system when we carried out the designs for BLDC Motor, Controller and water pump(Impeller, Volute Casing, Sealing Device) First, we attained ours purpose that the target efficiency for water pump was over 40% and then we are doing the optimum design for Brushless Motor and Controller that its target is over 55% of efficiency.

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PRELIMINARY STUDY OF WATER CONTENTS AND SIGNAL BEHAVIOR IN FINGERNAIL/EPR DOSIMETRY

  • Choi, Hoon;Choi, Sul A;Lee, Byungil
    • Journal of Radiation Protection and Research
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    • 제38권4호
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    • pp.185-188
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    • 2013
  • Heating method using electric heater was used to reduce water content in fingernail clippings. Authors found that low water content is helpful to measure EPR signal of fingernail sample with enhanced variability. Generally, natural dehydration happens in normal room condition at least one month and needs much time for using in experiment. So, artificial heating method is applied in this study for time savings. Fingernail samples were tested to find effect of water content to the EPR signal on microwave power levels for dosimetry. Low water content in fingernail reduced variability of EPR signal and makes it possible to measure accurate EPR signal. It also made it possible to measure constant movement of EPR signals on several microwave power levels. Although this method was difficult to apply directly in fingernail/EPR dosimetry, we, authors, believe that this heating method would be useful to differentiate MIS2 and RIS which are generally located at the same g-factor and almost impossible to be identified with each other.

Estimation of River discharge using Very High-Resolution Satellite Data in Yangtze River

  • Zhang, Jiqun;Xu, Kaiqin;Watanabe, Masataka;Sun, Chunpeng
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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    • pp.728-733
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    • 2002
  • The measurement of river discharge is among the most fundamental observations and is necessary for understanding many water-related issues, such as flooding hazards, sediment transportation, and nutrient movement. Traditionally river discharge is estimated by measuring the water stage and converting the measurement to discharge using a stage-discharge rating curve. The possibility of monitoring river discharge from satellites has been largely ignored, because it is difficult to measure water surface information from space with sufficient precision. In this paper, an efficient approach to discharge estimation using mainly satellite data is developed and described. The proposed method, which focuses on the measurement of water-surface width coupled with river width-stage and stage-discharge relationships, is applied to the Yangtze River with good results.

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상용 Gentoo 폴리머가 경화된 고체주입표면에서 물방울 거동 (Water droplet behavior on a solid-infused surface cured with commercial Gentoo polymer)

  • 김형원;김정현
    • 한국가시화정보학회지
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    • 제22권1호
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    • pp.61-67
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    • 2024
  • In this study, the behavior of water droplets on a solid-infused surface was evaluated by quantifying a water droplet's contact angle, sliding angle, and terminal velocity. The contact angle hysteresis and sliding angle of water on the solid-infused surface were measured to be lower than those of the hydrophobic PTFE surface. It led to the enhancement of the initiation of the water droplet's movement. When the capillary number was lower than Ca < 0.004, the terminal velocity of the water droplet on the solid-infused surface was higher than the PTFE surface due to the low contact line resistance. However, the transition of the droplet morphology from a hemispherical shape to a streamlined teardrop shape beyond Ca > 0.004 lost the effect of reducing frictional resistance on the solid-infused surface.

익모초의 약효 성분에 관한 연구(I) (Studies on Active Principles of Leonurus sibiricus)

  • 신순희
    • 생약학회지
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    • 제15권2호
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    • pp.104-107
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    • 1984
  • The essential oil fraction of Leonurus sibiricus was analyzed by TLC and gas chromatography. By utilizing silica gel column, a ketone compound, m.w. 167, was isolated from the essential oil. The essential oil showed considerably the diuretic action, but the water extract exhibited weak action. This diuretic action of the water extract was potentiated by combined administration of essential oil. On the isolated rabbit's uterus the essential oil decreased spontanous movement and showed relaxation.

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콘크리트의 부등건조수축으로 인한 응력의 해석 (Stress Analysis for Differential Drying Shrinkage of Concrete)

  • 김진근;김효범
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1994년도 봄 학술발표회 논문집
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    • pp.155-162
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    • 1994
  • The drying shrinkage of concrete has a close relation to the water movement, Since the diffusion process of water in concrete is strongly dependent on the temperature and pore humidity, the process is highly nonlinear phenomena. It is shown that the analytical results of this study are in good agreement with experimental data in the literatures, and results calculated by BP-KX model. The internal stress caused by moisture distribution which was resulted from the diffusion process, was calculated quantitatively. The tensile stress which occurred in the drying outer zone mostly exceeded the tensile strength of concrete, and necessarily would result in crack formation.

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합리적(合理的) 토양관리(土壤管理)를 위한 토양개량(土壤改良) (Soil Conditioning for better Soil Management)

  • De Doodt, M.
    • 한국토양비료학회지
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    • 제25권4호
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    • pp.311-324
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    • 1992
  • Polymeric substances in organic matter of soils aggregate soil particles into a crumb structure which greatly influences such properties as water movement, aeration and heat transfer. Poorly-structured soils may be improved by the incorporation of synthetic polymers where the main objects are : promoting germination or establishing crops, improving drainage, combating wind and water erosion, and reducing evaporation from the surface of soil under arid condition.

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제주도 동부해안 한동리지역의 수문지질학적 연구

  • 김기표;윤정수;박원배
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2002년도 추계학술발표회
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    • pp.9-12
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    • 2002
  • The purpose of this study is to understand the high saline water phenomenon of Handong-ri area in the eastern coast of Jeju Island, were investigate the tidal effect of groundwater level, variation of electric conductivity and temperature, geological logging on the monitoring wells, chemical water quality, and ratios of oxygen istope of groundwater and seawater Results in investigating variation of interface zone of freshwater and saline water represented that the hyaloclastites formed at below groundwater table is developing toward the coast; this area consisted of stratum of good permeability. Hyaloclastites is presumed the main path of the high salinity water There are a lot of movement by the tide at upper layer. Salinity of lower layer spreads to upper up step in proportion to tidal energy. Because of hydrogeological characteristics, Interface zone of freshwater and saline water is made, High salinity of groundwater occur in east coastal area of Jeju Island. Therefore, I think that high saline groundwater phenomenon is natural condition by simple mixing.

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Field Measurements of Wave Directionality in Water of Finite Depth

  • Memos, Constantine;Ziros, Athanassios
    • Ocean and Polar Research
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    • 제25권4호
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    • pp.437-446
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    • 2003
  • Field measurements of directional waves were carried out during the summer of 2002 at two coastal sites in water of finite depth. A couple of general purpose instruments were used employing acoustic Doppler technology. The aim of the study was to investigate the spatial behavior of the directional movement of waves as they come ashore. In total,74 tests were carried out during which sea states of low to moderate intensity were recorded. A great number of these runs displayed bimodal characteristics of the spreading function at high frequencies. It was found that in general, the frequency-integrated directional width tends to broaden as the water shoals and when refraction effects are negligible. This is attributed to wave-wave interactions that become pronounced in shallow water. The same directional width showed, also, a tendency to increase with increasing peak frequency of the sea state spectrum. The behavior of the kurtosis of the spreading function was also examined. It was found that for higher frequencies this index tends to increase in wave spectra above a certain sea severity threshold.

지리정보체계를 이용한 국부경사의 공간적 변동성 해석 (Analysis of Spatial Variability of Local Slope by Means of Geographic Information System)

  • 김주철;최용준;윤여진
    • 한국환경과학회지
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    • 제21권3호
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    • pp.297-303
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    • 2012
  • Slope is the geographic factor reflecting the 3-dimensional features of basin and it can be considered as the important geomorphological factor which governs the morphology of basin and the dynamics of water movement. In this study the approach to the 3-dimensional structures of basin is attempted with statistical analysis of local slope which can be defined and measured in easy and objective manner by means of DEM. As a result local slope is confirmed to be a highly variable spatial factor in basin. And distribution map of local slope based on spatial autocorrelation length in this study would be a useful tool in the further research of hydrology and geomorphology.