• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.128-129
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• 2002

• Korean Architects
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• s.630
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• pp.109-113
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• 2021

• Journal of Life Science
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• v.10 no.1
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• pp.6-9
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• 2000

Salmonella typhimurium is a causative agent of the common worldwide disease, salmonellosis. To identify putative invasion genes involved in Samonella infections, a S. typhimurium cosmid library was constructed in noninvasive E. coli DJl. The invasion efficiencies of the cosmid library for cultured HEp-2 and HeLa cells were estimated by tissue-culture invasion assay. 2 out of 1,000 transductants, DHl(pSI623) and DHl(pSI511) were able to invade the cells. Compared to E. coli by DHl(pSI511) increased 25- and 33 fold, respectively. The invasion efficiencies of HeLa cells by DHl(pSI623) increased 31- and 35 fold, respectively. This illustrates that the cosmid clones, DHl(pSI623) and DHl(pSI511) could harbor the invasion determinants derived from genomic DNA of S. typhimurium 82/6915, conferring the invasive characters for the cells.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.106-113
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• 2000

A pump which is a fundamental device in a hydraulic system affects on overall system performance to a great deal. Such problems as leakage and solid friction loss become important in field applications, especially for the case of operation under high pressure and at high speed. So the research on this kind of subjects is necessary to improve the performance of hydraulic devices. A high pressure radial piston pump is analyzed here, which has a stationary cylinder block. It pumps hydraulic fluid by letting camring push a piston in a cylinder. Fluid leaks between the piston and cylinder so that it deteriorates the pump efficiency. Furthermore, the piston happens to touch the cylinder wall to increase the friction loss and wear. In this research, by means of FDM, volumetric, mechanical and overall efficiencies are observed by varying several design Parameters and operation conditions. Design values or their trends are presented to improve these efficiencies.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1754-1759
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• 2011

The purpose of this paper is to provide basic information on how to make better policies that improves efficiencies of urban railways and to derive policy directions using DEA (data envelopment analysis) model. Through this paper, I can identify whether or not the urban railway service has an excellent performance, if there are any structural problems. I analyzed the efficiency by means of measuring the technical efficiencies of Korean urban railways, these were estimated with data envelopment analysis. The inputs considered are the length of urban railway lines, the number of staff, the operating cost, the number of cars, the number of stations, and the outputs are the cars movement, the traffic of passenger, and the revenue.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.4
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• pp.27-34
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• 1999

An experimental study on improvement of the paper-mill wastewater treatment using the pure oxygen activated sludge process was conducted. The effects of hydraulic retention time(HRT) and BOD loading on organic removal efficiency were investigated. The BOD removal efficiencies were above 90% under all examined HRTs except for HRT of 3 hours. The increase of HRT from 3 hours to 6 hours, and to 12 hours significantly improved BOD and COD removal efficiencies, respectively. However, additional increase of HRT did not affect organic removal efficiency. F/M ratio change at fixed HRT did not affect organic removal efficiency. However, F/M ratio investigated in this study(0.11~1.98kgBOD/kgMLVSS/day) was 5 times greater in maximum than that of conventional activated sludge process, which implies that pure oxygen activated sludge process can treat wastewater with high organic strength. Under the same HRT, the volumetric BOD loading change cause no effect on organic removal efficiency also.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.155-161
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• 2001

In this study, we analyzed the $NO_X$ removal efficiency and particle size distribution by the pulsed corona discharge process and investigated the effect of several process variables. The NO removal efficiencies and the particle characteristics were measured and analyzed as the function of initial concentrations of NO, $H_2O$, and $NH_3$, applied voltage, pulse frequency and residence time. As the frequency of applied voltage increases, or as the applied voltage increases or as the residence time increases, the NO removal efficiency increases. The change of initial $NH_3$ and $H_2O$ concentrations do not affect the NO removal efficiency significantly. The particle concentration and size increases with the increases of initial NO concentration, residence time and applied voltage.

• Journal of the Korean Chemical Society
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• v.13 no.2
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• pp.165-169
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• 1969

On the electrolytic preparation of sodium chlorate, lead dioxide anode, instead of graphite was tested to find out the characteristics for current efficiency and life in various conditions. The results obtained are summerized as follows; 1. The current efficiency is slightly increased with the anode current density, until 25A/$dm^2$ 2. The higher the current concentrations. the lower current efficiencies are observed, particularly in case of both not-adding the potassium dichromate and large current concentration of more than 50A/l 3. The current efficiency may be improved linearly as the both temperature is raised.

• Current Photovoltaic Research
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• v.6 no.2
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• pp.31-38
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• 2018

Multijunction solar cells present a practical solution towards a better photovoltaic conversion for a wider spectral range. In this review, we compare different types of multi-ijunction solar cell. First, we introduce thin film multijunction solar cell include to the thin film silicon, III-V material and chalcopyrite material. Until now the maximum reported power conversion efficiencies (PCE) of solar cells having different component sub-cells are 14.0% (thin film silicon), 46% (III-V material), 4.4% (chalcopyrite material) respectively. We then discuss the development of multijunction solar cell in which c-Si is used as bottom sub-cell while III-V material, thin film silicon, chalcopyrite material or perovskite material is used as top sub-cells.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.618-623
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• 2001

The transport of charged particles in electrostatic precipitator is investigated by Eulerian numerical analysis. Collection efficiencies are calculated using various combinations of the assumptions about flow field, turbulent diffusivity and boundary condition at collecting electrode. The characteristics of calculated collection efficiencies are compared with the trends of published experimental results. It is found that the collection efficiency for the case using nonuniform turbulent flow field, nonuniform turbulent diffusivity and zero concentration boundary condition at collecting electrode is the most suitable for the prediction of collection efficiency of electrostatic precipitator.