• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.201-204
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• 2008

Vortex and swirl occurring in a pump suction intake sump normally reduce the performance and disturb the safe operation of the circulation water pump in thermal power plants. This paper presents a case study of one particular intake sump design via a CFD analysis and a hydraulic model testing. The physical experiments and numerical analysis were performed under two flow and three level variation conditions. The vortex patterns around the pump suction pipe have been predicted by a commercial CFD code with the k-${\varepsilon}$ model. The model tests were conducted on a 1/10 model for a practical intake sump. The location, number and general pattern of the free surface vortex and submerged vortex predicted by CFD simulation were found to be a good agreement with those observed in the model testing.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.4
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• pp.257-266
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• 2000

A vertically-averaged, two-dimensional version of the Princeton Ocean Model has been applied to the South Sea to simulate the circulation driven by tides and inflows/outflows across open boundaries. To incorporate both forcing properly, a two-step modeling approach is adopted, in which the tidal circulation is first simulated by specifying the tides along the open boundaries, and then both the calculated tidal currents and the observed steady mean currents are prescribed across the open boundaries. Model results show that the steady, subtidal circulation of the South Sea is different from the residual circulation due to tidal rectification, and subtidal currents become locally as strong as tidal currents. The Cheju Current entering the model domain across the Cheju Strait flows eastward in general while shifting onshore or offshore areas following local isobaths. The Tsushima Current entering across the southern boundary reaches farther to the north in the eastern vicinity of Cheju-Do as compared to that entering across other parts of the southern boundary. The Tsushima Current turns to the east, merges with the Cheju Current, and both the Cheju and Tsushima Current exit to the East Sea through the western channel of the Korea Strait. An intensification of the outflow occurs over the deep trough adjacent to the Tsushima Island, which appears to be due to the formation of the frictional boundary layer in order to remove excess positive relative vorticity generated by an increase in the layer thickness. The circulation driven by both the tidal and inflows/outflows is different from that driven by each forcing separately in coastal areas, which implies that both forcings should be considered simultaneously in the simulation of more realistic coastal circulation.

• Journal of Korean Library and Information Science Society
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• v.9
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• pp.63-83
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• 1982

Among many open libraries under the rule of the Japanese imperialism, only the railroad library as the character of special library under the control of the Japanese Government General is remarkable for having opened its facilities to outsiders as well as the interior users. This study tries a) To look into what were the colonial background, aim and motive of the establishment of the railroad library under the Japanese rule, b) To analyze its activities and the change of its organization, c) And to find out its vestiges an the effects which it has on our country's library circles. The following are the result: A. The railroad library under the rule of the Japanese imperialism functioned as a public library by the outside book's circulation rather than the interior using. B. The outsiders were qualified to use it only when they got the joint guarantee for the city resident, which means that the o n.0, pportunity of the circulation was not free for the Koreans rather than the Japanese. C. From the aspect of collections, technical books such as natural science, and reference ones tended to be collected, and their whole composition was focused on the materials for the Japan-Korea identification scheme and development of the national spirit as the Japanese empire's subjects. D. In the respect of its organization, all the clerical employees, as well as the chief librarian were composed of the Japanese. Although the Koreans were in principle prohibited from working there, a few of them were employed as guard or servant as the China-Japan War was close to the end. E. The area of the outside book's, circulation service was expanded throughout the whole region along the railroad connecting Pusan with Manchuria. Such a service activity which contained several meanings, was tried by means of culture's books, circuit's books, train's books, hotel's books, mind's development books and reader's reading books etc. F. Such matters as the limitation on book circulating and the quantity of circulation book, the paid circulation and the partial restriction on free circulation mean the wartime system under the rule of the Japanese imperialism and also a n.0, ppeared as a factor of hampering the Koreans from getting accustomed to using library, which has affected them until now. G. The noticeable thing in the service activity is shown in attempting the diversified and positive way of service like free circulation in order to solidify the attitude of the Koreans toward war by organizing mind's development books as well as culture's books with the China-Japan War. H. On the other hand, it can not be passed over that the diversified service activity of the railroad library played a role of bridge in turning of today's library circles of ours to the modernization.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.2
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• pp.333-356
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• 2010

Small libraries, with their insufficient quantities of materials and lack of diversity within the collection compared to larger general public libraries, may need to be assessed and develop collections based on empirical analysis. This study suggests a method for collection evaluation with other cases analyzing ILL (interlibrary loan) data, which is especially heavy in Small libraries in addition to the holdings and circulation data that are traditionally used in collection development. Collecting and analyzing materials proceeded from 14 Small libraries which operate ILL in a city and tried to figure out features of each library comparing collection statistics with usage statistics including circulation and interlibrary loans. It also identified subject areas heavily used in a Small library, based on the analysis of collection and usage statistics, for the purpose of formulating future policy.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.205-213
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• 1985

It is well documented that calcium is essential to cardiac contraction and the amplitude of contractility is proportional to the ionized calcium not to total calcium. Changes of serum ionic calcium before and after extracorporeal circulation were observed in fifty two patients operated on at Dept. of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, from May 21st, 1984, to July 6th, 1984. They were 28 males and 24 females including 21 acyanotic congenital heart diseases, 21 cyanotic congenital heart diseases, and 10 acquired valvular heart diseases. In general, preoperative serum ionic calcium was around the normal level, but those of immediate postoperative day and postop-first day were decreased subnormally with significance [P<0.05 vs. preop.]. From postop-third day, serum ionic calcium was returned to normal range. No significant difference was noticed in subgroups divided by 10 Kg of body weight and by the methods of myocardial protection. But the change of serum ionic calcium in the patients with prolonged pump time over 90 minutes was remarkable and the values were as follow; on immediate postop-day 1.780.18 mEq/L vs. 1.970.20 mEq/L [P<0.005],on postop-first day, 1.940.20mEq/L vs. 2.060.12 mEq/L [P<0.025], on postop-third day, 2.030.11mEq/L vs. 2.150.13mEq/L [P<0.01], and on postop-seventh day, 2.030.09mEq/L vs. 2.190.11mEq/L [P<0.005]. In summary, the serum ionic calcium was lowered after extracorporeal circulation and even severer degree according to the prolongation of bypass time. So, after extracorporeal circulation esp. in the cases with prolonged bypass time, early correction of lowered serum ionic calcium would be helpful to the postoperative hemodynamics.

• Journal of the korean society of oceanography
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• v.39 no.1
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• pp.72-95
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• 2004

The Yellow Sea is characterized by relatively shallow water depth, varying range of tidal action and very complex coastal geometry such as islands, bays, peninsulas, tidal flats, shoals etc. The dynamic system is controlled by tides, regional winds, river discharge, and interaction with the Kuroshio. The circulation, water mass properties and their variability in the Yellow Sea are very complicated and still far from clear understanding. In this study, an effort to improve our understanding the dynamic feature of the Yellow Sea system was conducted using numerical simulation with the ROMS model, applying climatologic forcing such as winds, heat flux and fresh water precipitation. The inter-annual variability of general circulation and thermohaline structure throughout the year has been obtained, which has been compared with observational data sets. The simulated horizontal distribution and vertical cross-sectional structures of temperature and salinity show a good agreement with the observational data indicating significantly the water masses such as Yellow Sea Warm Water, Yellow Sea Bottom Cold Water, Changjiang River Diluted Water and other sporadically observed coastal waters around the Yellow Sea. The tidal effects on circulation and dynamic features such as coastal tidal fronts and coastal mixing are predominant in the Yellow Sea. Hence the tidal effects on those dynamic features are dealt in the accompanying paper (Kim et at., 2004). The ROMS model adopts curvilinear grid with horizontal resolution of 35 km and 20 vertical grid spacing confirming to relatively realistic bottom topography. The model was initialized with the LEVITUS climatologic data and forced by the monthly mean air-sea fluxes of momentum, heat and fresh water derived from COADS. On the open boundaries, climatological temperature and salinity are nudged every 20 days for data assimilation to stabilize the modeling implementation. This study demonstrates a Yellow Sea version of Atlantic Basin experiment conducted by Haidvogel et al. (2000) experiment that the ROMS simulates the dynamic variability of temperature, salinity, and velocity fields in the ocean. However the present study has been improved to deal with the large river system, open boundary nudging process and further with combination of the tidal forcing that is a significant feature in the Yellow Sea.

• The Journal of Korean Physical Therapy
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• v.26 no.4
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• pp.220-225
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• 2014

Purpose: This study aims to investigate the impact of a short walk putting on Coolfin shoes on the foot temperature rise and blood circulation. Methods: Twenty healthy adults participated in experiments in this study. All subjects walked respectively barefoot and putting on Coolfin shoes. Infrared imaging cameras were used to collect and analyze the data on the foot temperature. Results: As a result of this study, there were significant differences between the temperatures of the great toe and top of the foot after 20-minute walks with bare feet and in Coolfin shoes. Both the temperatures of the great toe and top of the foot decreased after a 20-minute walk in the barefoot condition, and there was a significant difference between them (p<0.05). Both the temperatures of the great toe and top of the foot increased after a 20-minute walk in the condition of putting on Coolfin shoes, and there was a significant difference between them(p<0.05). Conclusion: A short walk putting on Coolfin products induces the movement of the toes to increase the blood flow and accordingly, has a direct impact on the increase of the surface temperature of the feet, so they are effective products for helping blood circulation in the feet.

• Culinary science and hospitality research
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• v.13 no.1 s.32
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• pp.75-86
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• 2007

This study was carried out to find out the effect of food hygiene awareness on kitchen employees' performance in the banquet cuisine of five-star hotels in Seoul. 279 kitchen employees were asked to fill out the questionnaire, and the collected data were analyzed by SPSS package(version 11.0). First, results of analysis on food hygiene showed that there were four factors, each respectively named as, food security regulations, food storage, period of circulation of food, and food safekeeping. Second, after analyzing each item in whole according to each of the factors, the average degree of priority on food hygiene in general was 4.52. Results according to each of the elements showed that food security regulations(4.56) and period of circulation of food(4.55) were considered as a priority. After analyzing the difference between the degree of priority and degree of performance according to each of the factors, it was found out that the latter was significantly lower than the former in all factors. Third, after analyzing the difference of food hygiene priority in accordance with general characteristics, statistically significant difference was only shown in education(F=3.308, p<0.05) and class(F=4.418, p<0.01). Fourth, after analyzing the difference of food hygiene performance in accordance with general characteristics, the only significant difference was found in food security regulation of education(F=4.418, p<0.01) and food security regulation of class(F=3.859, p<0.01). Fifth, after analyzing the effect of cook's awareness of priority on food hygiene on the degree of performance, it was found out that the awareness of priority on food hygiene had a positive effect(+) on the degree of performance. Therefore, we can conclude that as kitchen employees recognize the priority on the food hygiene better, their degree of performance was higher.

• Journal of Korea Water Resources Association
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• v.32 no.6
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• pp.617-625
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• 1999

Global warming has begun since the industrial revolution and it is getting worse recently. Even though the increase of greenhouse gases such as $CO_2$ is thought to be the main cause for global warming, its impact on global climate has not been revealed clearly in rather quantitative manners. However, researches using General Circulation Models(GCMs) has shown the accumulation of greenhouse gases increases the global mean temperature, which in turn impacts on the global water circulation pattern. This changes in global water circulation pattern result in abnormal and more frequent meteorological events such as severe floods and droughts, generally more severe than the normal ones, which are now common around the world and is referred as a indirect proof of global warming. Korean peninsula also cannot be an exception and have had several extremes recently. The main objective of this research is to analyze the impact of global warming on the change of flood and drought frequency. Based on the assumption that now is a point in a continuously changing climate due to global warming, we analyzed the observed daily rainfall data to find out how the increase of annual rainfall amount affects the distribution of daily rainfall. Obviously, the more the annual rainfall depth, the more frequency of much daily rainfall, and vice versa. However, the analysis of the 17 points data of Keum river basin in Korea shows that especially the number of days of under 10mm or over 50mm daily rainfall depth is highly correlated with the amount of annual rainfall depth, not the number of dry days with their correlation coefficients quite high around 0.8 to 0.9.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.15-22
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• 2020

The landfill gas produced in landfill is generally made up of methane(CH4) and carbon dioxide(CO2) of more than 90%, with the remainder made up of hydrogen sulfide(H2S). However, separate pre-treatment facilities are essential as hydrogen sulfide contained in landfill gas is combined with oxygen during the combustion process to generate sulfur oxides and acid rain combined with moisture in the atmosphere. Various desulfurization technologies have been used in Korea to desulfurize landfill gas. Although general desulfurization processes apply various physical and chemical methods, such as treatment of sediment generation according to the CaCO3 generation reaction and treatment through adsorbent, there is a problem of secondary wastes such as wastewater. As a way to solve this problem, a biological treatment process is used to generate and treat it with sludge-type sulfide (S°) using a biological treatment process.In this study, as a basic study of technology for utilizing the biological treatment by-products of hydrogen sulfide in landfill gas, an experiment was conducted to use the by-product as a mixture of concrete. According to the analysis of the mixture concrete strength of sulfur products, the mixture of sulfur by-products affects the strength of concrete and shows the highest strength value when mixing 10%.