• Journal of Advanced Marine Engineering and Technology
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• v.24 no.5
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• pp.25-32
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• 2000

In this paper, experiments investigating the high-temperature region heat transfer coefficients for the spray cooling of hot flat plates were performed by down spray water using flat spray nozzles. The heat transfer surface is made of copper and is 100mm in length and 40mm in width and 15mm in thickness. The experimental condition of spray are as follows: temperatures of the water droplets are T=20~$80^{\circ}C$ and droplets volume fluxes are D=0.001565~0.010438$m^3/m^2s$. Next, correlating equations for the heat transfer characteristics of spray cooling in the high temperature region are developed from the effects of droplets volume flux and the surface temperature of heat transfer plate.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.201-206
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• 2021

The significance of high-quality development and green total factor productivity has attracted widespread attention and research, while few studies on green total factor productivity that considers the use of water resources have been conducted in the context of water shortages and water stress. In this study, the green total factor productivity of water use from 2005 to 2015 in mainland China is evaluated based on the global Malmquist-Luenberger productivity index. Results show that: (1) China's green total factor productivity of water use has been improving since 2005 with an annual global Malmquist-Luenberger productivity index of 1.0104. (2) At the regional level, the eastern zone in mainland China owns the highest green total factor productivity of water use, while that in the intermediate zone ranks last. (3) The green total factor productivity of water use in the southern region (1.0113) significantly higher than that in the northern region (1.0095), and also higher than the national average level in the same period. BPC index has been the most important incluencing factor of green total factor productivity of water use at both national level and regional level since 2011.

• 수도
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• s.64
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• pp.72-79
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• 1993

• Water for future
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• v.43 no.8
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• pp.82-86
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• 2010

• Ocean and Polar Research
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• v.30 no.3
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• pp.289-301
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• 2008

Community structure of heterotrophic protists and their grazing impact on phytoplankton were studied in Northwest Pacific Ocean during October, 2007. The study area was divided into four regions based on physical properties (temperature and salinity) and chlorophyll-a distribution. They were Region I of North Equatorial Currents, Region II of Kuroshio waters, Region III of shelf mixed water, and Region IV of Tsushima warm current from East China Sea. The distribution of chlorophyll-a concentrations and community structure of heterotrophic protists were significantly affected by physical properties of the water column. The lowest concentration of chlorophyll-a was identified in Region I and II, where pico-sized chlorophyll-a was most dominant (>80% of total chlorophyll-a). Biomass of heterotrophic protists was also low in Region I and II. However, Region III was characterized by low salinity and temperature and high chlorophyll-a concentration, with relatively lower pico-sized chlorophyll-a dominance. The Highest biomass of heterotrophic protists appeared in Region III, along with the relatively less important nanoprotists. In Region I, II and IV, heterotrophic dinoflagellates were dominant among the protists, while ciliates were dominant in Region III. Community structure varied with physical(salinity and temperature) and biological (chlorophyll-a) properties. Biomass of heterotrophic protists correlated well with chlorophyll-a concentration in the study area ($r^2=0.66$, p<0.0001). The potential effect of grazing activity on phytoplankton is relatively high in Region I and II. Our result suggest that biomass and size structure of heterotrophic protists might be significantly influenced by phytoplankton size and concentration.

• Journal of Environmental Science International
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• v.15 no.9
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• pp.871-880
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• 2006

Water management treatment of coastal region has been an important problem in Jeju city since the distributions of pipeline of the pumping system made a bad view in coastal region. To solve the problem, we observed the pipelines that are on the surface around the coastal region from Tapdong to Doduhang. From the observations, we found that Todong and Dodu areas were not unsightliness because the all pipelines were located in underground. However, the other areas, such area Yongdam, Handugi, Yongdam fishing village, had a serious problem for the coastal landscape view. To solve the problem, at we estimated coastal land color characteristics of Jeju city based on the observation of the pipelines. The estimated color panel shows that the green, blue and grey colors are a dominant factors of the Jeju coastal region. Based on the color panel, we proposed two methods, that is, one is a short time treatment, the other is a long time one. The short is based on the colour treatment, which is pipeline colour changing into surround natural one. The long time is the construction plan design method. Although the later method was very useful in Jeju island. However, it takes a lot of time and money. Therefore, in the situation, the short time is the better than the long time one.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.3
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• pp.247-255
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• 2004

The cooling characteristic of water-air mixed spray for high water mass flux is not well defined, compared to that of highly pressurized spray. A series of research program was planned to develop the boiling correlation for whole temperature range in case of water-air mixed spray with high water mass flux. The cooling experiments of hot steel surface with initial temperature of 820$^{\circ}C$ were conducted in unsteady state with relatively high water mass flux. A computer program was developed to calculate the heat flux inversely from measured data by three inserted thermocouples. Finally the effects of water and air mass flux on the averaged film boiling heat flux and wetting temperature were studied. In this 1st report, it is found that the boiling curve was similar to that of highly pressurized spray and the decreased slope of heat flux in film boiling region with respect to surface temperature became steep by increasing air mass flux. Also it is shown that, by increasing air mass flux, the averaged heat flux in film boiling region was increased, and then saturated and the wetting temperature was increased, and then decreased. Finally when the heat flux in film boiling region is compared with that of highly pressurized spray, it is known that the cooling is improved by introducing air up to 60%.

• Journal of Ocean Engineering and Technology
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• v.19 no.1 s.62
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• pp.14-19
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• 2005

As a basic study for establishing the input conditions of a forecasting/estimating model, used for deep-sea water drainage to the ocean, this study was carried out as follows: 1) estimating the amount of river discharge and pollutant loads into the developing region of deep sea water in the East Sea, Korea, 2) a field observation of tidal current, vertical water temperature, and salinity distribution, 3) 3-D numerical experiment of tidal current to analyze the physical oceanographic status. The amount of river discharge flowing into this study area was estimated at about $462.7{\times}103 m\^3/day$ of daily mean in 2002. Annual mean pollutant load of COD, TN, and TP were estimated at 7.02 ton-COD/day, 4.06 ton-TN/day, and 0.39 ton/day, respectively. Field observation of tidal current normally shows 20-40cm/sec of current velocity at the surface layer, and it decreases under 20cm/sec as the water depth increases. We also found a stratification condition at around 30m water depth in the observation area. The differences in water temperature and salinity, between the surface layer and the bottom layer, were about 18 C and 0.8 psu, respectively. On the other hand, we found a definite trend of 34 psu salinity water mass in the deep sea region.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.1
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• pp.20-33
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• 2006

Changing of industry structure and development of traffic and telecommunications requires a change of the knowledge about the space where the human beings reside. Step by step the world is being divided into specified utility blocks. Today there is a limit that only one local government can compete with another region in the world. This study provides decision support tools with the use of GIS on the regional level for regions competition. GIS establishes regions and analyzes their geographic environment data, which will help in local-government problem solving and provide framework data for similar regions to become the community. The wide-area GIS application can present an objective and rational basis for regulation of inefficient investments and excessive competition between adjacent regions. The study area is Gangwon-do. Considering specific features of Gangwon-do which preserved high-quality environment resources, river basins were taken as a basis among natural regional elements. The main object of analysis conducted were the facts relevant to environmental regulation. The Gangwon-do consists of three regions in this study: Yongdong region, North-Hangang region and South-Hangang region. The analysis of each region regulation cases showed the following: in Youngdong region the forests regulation rate is high, in North-Hangang region the military installations protection sector's rate as well as regulation rate for water resources protection is relatively high, in South-Hangang region the forest and water resources regulation rate is high. The percentage of forests and water regulation rate appeared to be rather high in Gangwon-do, which means that the value of forest and water resources there is very high.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.2
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• pp.129-139
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• 2005

We investigated the characteristics of the thermohaline structure and phytoplankton community from the southwestern areas of Jeju to the nothern areas of Taiwan in the Ease China Sea, in June 2004. According to the analysis of a T-S diagram, three characteristic of water masses were identified. We classified them into the mixed water mass by the Chiness continental coastal waters and Yellow Sea cold water (Region A), Chinese continental coastal waters (Region B) and Taiwan warm current (Region C). Region A was characterized by low temperature, low salinity, high density and high Chl-a concentration. Region B was characterized by high temperature, low salinity, low density and high Chl-a and Region C was characterized high temperature, high salinity, low density and low Chl-a concentration. The phytoplankton community identified a total of 56 species belonging to 31 genera. The dominant species was mainly dinoflagellates, Gymnodinium breve, Scrippsiella trochoidea, Ceratium fusus, Prororcentrum triestinum, centric diatoms, Chaetoceros lorenzianus, Leptocylindrus danicus, Proboscia alata, Skeletonema costatum and pennate diatoms, Pseudonitzschia pungens, Cylidrotheca closterium. Standing crops of phytoplakton fluctuated between $0.1{\times}10^2$ cells/L and $5.7{\times}10^4$ cells/L by dominance of dinoflagellates. In the phytoplankton community, the Region A was characterized by the various species composition in 39 species, the dominint species with di-atomes, Pn. pungen, Ch. lorenzianus and standing crops from 6.9 cells/$m\ell$ to 56.6 cells/$m\ell$, Region B by the various species composition in 37 species, the dominant species with dinoflagellates, G.breve, S. trochoidea and standing crops from 4.6 cells/$m\ell$ to 26.7 cells/$m\ell$, and the Region C by low species number with 28 species, the dominant species with one dinoflagellate, S.trochoidea and one diatom, L.danicus and very low standing crops from 0.1 cells/$m\ell$ to 5.7 cells/$m\ell$. Phytoplankton productivity in the East China Sea was controlled by Chinese continental coastal waters which include a high concentrations of nutrients.