• Ocean and Polar Research
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• 제42권2호
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• pp.97-113
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• 2020

In-situ observations were carried out in April 2015 to investigate the occurrence of water temperature inversion in a region west of Jeju Island. Analysis of in-situ in the western part of Jeju island showed that cold water moved to the southeast from the surface to the middle layer and warm water moved from the middle to the lower layer of the northwest direction. The water temperature inversion occurred at 84 stations (63.1%) out of 133 stations. At the boundary of the water temperature inversion layer, it was formed in the middle layer and disappeared. In the strongly appearing, it started from the middle layer to the lower layer. The shape of the water temperature inversion layer was different. As a result of horizontal water temperature slope analysis of the water temperature inversion zone, maximum 0.23℃/km was obtained and the mean was 0.06℃/km. The role of water temperature inversion as an indicator to determine the formation of water front. As a result of the water mass analysis, Jeju Warm Current Water and Tsushima Warm Current Water of high temperature and high salt intruded from the middle to the bottom. In the middle layer occurred as the Yellow Sea Cold Water of low water temperature and low salinity expanded.

• 한국의류산업학회지
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• 제11권2호
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• pp.359-362
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• 2009

This study investigates the behavior of water vapor permeability of a layered system to find out a comfortable combination of a layered system for outdoor activities and examines the water vapor permeability of various types of outdoor clothing fabrics. The layered system includes the base layer such as sportswool and polyester/cotton fabrics, the middle layer such as single and double sided fleece fabrics, and the shell layer such as polyurethane-coated, PTFE-laminated and microfiber fabrics in this experiment. Results show that the layered system was applied, it was working together as a whole having some influence on each other layer, though every layer offered varying degree of water vapor permeability. Water vapor permeability of layered system exactly followed the same trend as the shell layer, which is all vapor permeable water repellent fabrics as a single layer. The rate of water vapor transfer through a layered system is mainly related to the type of vapor permeable water repellent fabrics used for the shell layer.

• Tribology and Lubricants
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• 제19권5호
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• pp.245-250
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• 2003

Water is known to playa crucial role on friction of moving parts in nanoscale contact. Little is, however, known about the tribological behavior of a solid surface that is covered with water adsorption layer. The objective of this study is to investigate the nanotribological behavior of the water layer in relation to water affinity of the surface and relative humidity. This paper presents an examination of the frictional behavior of water adsorption layer as 'confined liquid film'. It is shown that the friction is inversely proportional to the hydrophilicity of surface and relative humidity. On the other hand, friction of hydrophobic surface is not influenced by relative humidity. A model is proposed for the water-mediated contact in which it is shown that the water layer between two hydrophilic surfaces with high relative humidity behaves as a lubricant.

• 한국의류산업학회지
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• 제8권6호
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• pp.709-712
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• 2006

The aim of this study is to find out comfortable combinations of layered system for outdoor activities through water vapor permeability. Layering fabrics is an effective way of controlling water transport properties in fabric systems for outdoor activities and analysis of these systems may be useful for designing comfortable clothing. Seven fabrics were chosen for the experiments: two fabrics for base layer, two for the middle layer and three for the shell layer. A total of 12 different layered systems, which are all possible combinations were established using selected fabrics. The water vapor permeability was measured using JIS L1099 under isothermal and non-isothermal conditions. It was found that layered system was working together as a whole having influence on each layer, though every layer offers varying degree of water vapor permeability. Furthermore, it was also found that an optimal combination of the three layered system does exist although the combination may differ according to the ways. The shell layer is the greatest effect of water vapor permeability under isothermal and non-isothermal conditions within layered system.

• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2004년도 학술대회
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• pp.25-25
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• 2004

We studied algal growth-related water quality of the Dongbok lake which is the drinking water reservoir for the Gwangju municipality. Peridinium cinctum and several diatomic algal species frequently caused water bloom throughout the lake from early spring to late autumn. With the heaviest predominance of Peridinium cintum in May 2003, COD was 13.7 mg/I in the surface layer. Highly turbid surface water with 46.8 mg/I of SS was also caused by Perdinium bloom. Peridinium bloom decisively eliminated cyanobacterial growth in the lake, otherwise cyanobacterial bloom resulted. Dense algal layer was confined in the upper several meters of the water column above the thermocline, which gives relatively algae-free water in deeper layer suitable for drinking source water supply. Upon collapse of thermocline, water quality of the surface layer was improved while deeper layer was deteriorated in terms of water quality. This paper deals with some details of water quality changes with algal growth in the Dongbok lake past two years.

• 환경영향평가
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• 제21권5호
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• pp.715-724
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• 2012

In this study, we simulated water temperature in the downstream according to withdrawal types of dam using EFDC model. Three scenarios were assumed as water was released from the surface layer, the middle layer, and the bottom layer at intervals of 10m depth. In case of the surface layer withdrawal, the water temperature rose from March and lowered gradually after it reached a peak in August. The middle and the bottom layers effluence temperatures were lower than the surface layer temperature by maximum $15.9^{\circ}C$(in July), but after September, temperature inversion appeared. It was advantageous for the surface layer withdrawal to decrease cold damage and fog in downstream area and was possible to the middle and the bottom layers withdrawal from August to September. However, the reliability of model should be improved by accumulating the real-time information of water temperature.

• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2004년도 학술대회
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• pp.27-27
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• 2004

We studied algal growth-related water quality of the Sangsa lake which is the drinking water reservoir for the south-eastern region of Jeonnam province. Peridinium cinctum and several diatomic algal species frequently caused water bloom throughout the lake from early spring to late autumn. With the heaviest predominance of Peridinium cintum in May 2003, COD was 22.7 mg/l in the surface layer. Highly turbid surface water of 15 NTU was also caused by Perdinium bloom. Cyanobacterial growth was effectively prohibited by dominant growth of Peridinium in the Sangsa lake, otherwise confronted with cyanobacterial bloom. Dense algal layer was confined in the upper several meters of the water column above the thermocline, which gives relatively algae-free water in deeper layer suitable for drinking source water supply. Upon collapse of thermocline, water quality of the surface layer was improved while deeper layer was deteriorated. This paper deals with some details of water quality changes with algal growth in the Sangsa lake past two years.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.46-53
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• 2011

Water is continuously produced in polymer electrolyte membrane fuel cell (PEMFC), and is transported and exhausted through polymer electrolyte membrane (PEM), catalyst layer (CL), microporous layer (MPL), and gas diffusion layer (GDL). The low operation temperatures of PEMFC lead to the condensation of water, and the condensed water hinders the transport of reactants in porous layers (MPL and GDL). Thus, water flooding is currently one of hot issues that should be solved to achieve higher performance of PEMFC. This research aims to study liquid water transport in porous layers of PEMFC by using pore-network model, while the microscale pore structure and hydrophilic/hydrophobic surface properties of GDL and MPL were fully considered.

• 한국환경과학회지
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• 제12권5호
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• pp.521-527
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• 2003

To study the intruded phenomena of North Pacific Ocean around Boso peninsular, water property distribution in the adjacent seas to Japan is studied using the hydrographic data obtained by Japan Maritime Agency and Japan Fisheries Agency from 1973 to 1996, The scattering of water type in T-5 diagram is relatively small in the Kuroshio Region. Both the envelopes of saline side and of fresh side of the scattered data points shifts gradually from saline side to fresh side as the observation Line moves from southwest to northeast. In mixed water region, the scattering of water type increases rapidly as the observation line moves north; the envelope of fresh cold side moves towards fresh cold side much faster than that of saline side. This suggests that the water does not advect along the salinity minimum layer, but the salinity minimum layer can be understood as a boundary of two different waters aligned vertically, We defined the typical water masses as the Oyashio Water and the Kuroshio Water. The water mass below the salinity minimum layer may be created by isopycnal mixing of these two water masses with a fixed mixing rate. While the water mass above the salinity minimum cannot be created simply by isopycnal mixing. The salinity minimum layer may be eroded from upper side due to active minxing processes in the surface layer, while the water of the salinity minimum layer moves gradually southward. This appears to give an explanation why the thermosteric anomaly value at salinity minimun decereases towards south.

• Ocean Science Journal
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• 제41권4호
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• pp.255-260
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• 2006

Long-term variability in the intermediate layer of the eastern Japan Basin has been investigated to understand the variability of water mass formation in the East Sea. The simultaneous decrease of temperature at shallower depths and oxygen increasing at deeper depths in the intermediate layer took place in the late 1960's sand the mid-1980's. Records of winter sea surface temperatures and air temperatures showed that there were cold winters that persisted for several years during those periods. Therefore, it was assumed that a large amount of newly-formed water was supplied to the intermediate layer during those cold winters. Close analysis suggests that the formation of the Upper Portion of Proper Water occurred in the late 1960's and the Central Water in the mid-1980's.