• 한국철도학회논문집
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• 제8권6호
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• pp.581-585
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• 2005

In this study, the environmental impacts of a bogie in the electric motor unit(EMU) were evaluated quantitatively using simplified life cycle assessment(S_LCA). Target was the bogie and life cycle inventory(LCI) database for the bogie was established. The software used for simplified LCA was PASS. Environmental impacts with the parts of the bogie were dependent on their weight significantly. Among impact categories, abiotic resource depletion(ARD) and global warming(GW) were shown dominantly. Global warming was occurred mainly due to the emission of CO₂released from energy consumption and abiotic resource depletion was caused mostly by the consumption of iron ore for the manufacturing of steel. Therefore, the environmental impacts of the bogie could be reduced by the light-weighting of EMU and the improvement of energy efficiency.

• 반도체디스플레이기술학회지
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• 제14권3호
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• pp.27-31
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• 2015

It was the electrical properties of ZnS treated by the annealing in a vaccum and an atmosphere conditions to reseached the leakage current effect of semiconductor devices. Most samples were shown the non-linear with unipolar properties, but the ZnS annealed at $100^{\circ}C$ in a vaccum was only observed no leakage current in a range of -20 V< voltage < 15 V. The crystallinity of ZnS with no leakage current was improved and optical property was also improved. Because the ambipolar characteristics and low leakage currents originated from the extension effect of a depletion width by electron-hole combination in the depletion layer.

• 대한전자공학회논문지
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• 제25권12호
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• pp.1656-1662
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• 1988

Auger depth profiles of various In Ga As P/In P heterojunctions grown by liquid phase epitaxial techniques under different growth conditions such as diffusion temperature, diffusion time and dopants, have been obtained. The surface contaminations of In Ga As have been investigated. We found that the samples with Zn diffusion exhibit significant interface grading phenomena including In depletion, Ga richness and P richness at the In Ga As P/In P interface, and In outdiffusion at the surface. The main surface contamination was found to be due to carbon and oxygen species. It can be suggested that Zn gettering takes a major role in such phenomena as interface grading, in depletion, and Ga and P richness at the interface.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2005년도 춘계학술대회 논문집
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• pp.5-9
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• 2005

One of the imminent problems to be solved within wireless sensor network is to balance out energy dissipation among deployed sensor nodes. In this paper, we present a transmission relay method of communications between BS (Base Station) and CHs (Cluster Heads) for balancing the energy consumption and extending the average lifetime of sensor nodes by the fuzzy logic application. The proposed method is designed based on LEACH protocol. The area deployed by sensor nodes is divided into two groups based on distance from BS to the nodes. RCH (Relay Cluster Head) relays transmissions from CH to BS if the CH is in the area far away from BS in order to reduce the energy consumption. RCH decides whether to relay the transmissions based on the threshold distance value that is obtained as a output of fuzzy logic system. Our simulation result shows that the application of fuzzy logic Provides the better balancing of energy depletion and Prolonged lifetime of the nodes.

• 반도체디스플레이기술학회지
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• 제15권1호
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• pp.70-75
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• 2016

GZO films prepared on ITO glasses were annealed at various temperatures in a vacuum condition to research the relationship between oxygen vacancies and optical properties. GZO films after annealing in a vacuum showed the various optical-chemical properties depending on the annealing temperatures and oxygen gas flow rate during the deposition. The oxygen vacancy of GZO film prepared by oxygen gas flows of 22 sccm increased with increasing the annealing temperatures, because of the extraction of oxygen by the annealing. But the intensity of photoluminance of GZO with 22 sccm decreased in accordance with the annealing temperature, because of the reduction of ionized charge carriers. The oxygen vacancy by the extraction of oxygen enhanced a depletion, so the widen depletion had the strong Schottky barrier and the PL intensity due to the low carrier density decreased.

• 한국미생물·생명공학회지
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• 제25권3호
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• pp.240-247
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• 1997

Bacillary is the most common form of H. pylori observed during human infection. However, it is known that the morphology change of H. pylori from bacillary to coccoid can be occurred with a response to the environmental stresses such as the nutrient depletion, accumulation of toxic metabolites, pH alteration, and exposure to antimicrobial agents. The coccoid form of H. pylori, which is viable but non-culturable in vitro, seems to be the major cause of antibiotic resistancy and high reinfectability of H. pylori. In this regard, we studied the environmental factors that can induce the morphological change in vitro of H. pylori, and the change of fatty acid composition of plasma membrane. The morphological change from bacillary to coccoid could be observed with the depletion of nutrients, pH variation and reactive oxygen species added in the culture media. This morphologic conversion was paralleled by a dramatic decrease in unsaturated fatty acids and an increase in saturated fattv acids of plasma membrane. The change in composition of membrane fatty acid seems to be a kind of protection mechanism of H. pylori against these environmental stresses.

• 한국표면공학회지
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• 제48권3호
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• pp.126-130
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• 2015

A high-pressure depletion method using plasma chemical vapor deposition (CVD) is often used to deposit hydrogenated microcrystalline silicon (${\mu}c-Si:H$) films of a low defect density at a high deposition rate. To understand proper deposition conditions of ${\mu}c-Si:H$ films for a high-pressure depletion method, Si films were deposited in a combinatorial way using a multi-hollow discharge plasma CVD method. In this paper the substrate temperature dependence of ${\mu}c-Si:H$ film properties are demonstrated. The higher substrate temperature brings about the higher deposition rate, and the process window of device quality ${\mu}c-Si:H$ films becomes wider until $200^{\circ}C$. This is attributed to competitive reactions between Si etching by H atoms and Si deposition.

• Journal of Astronomy and Space Sciences
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• 제32권1호
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• pp.13-19
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• 2015

Plasma bubbles that occur in the equatorial F-region make up one of the most distinguishing phenomena in the ionosphere. Bubbles represent plasma depletions with respect to the background ionosphere, and are the major source of electron density irregularities in the equatorial F-region. Such bubbles are seen as plasma depletion holes (in situ satellite observations), vertical plumes (radar observations), and emission-depletion bands elongated in the north-south direction (optical observations). However, no technique can observe the whole three-dimensional structure of a bubble. Various aspects of bubbles identified using different techniques indicate that a bubble has a "shell" structure. This paper reviews the development of the concepts of "bubble" and "shell" in this context.

• 환경위생공학
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• 제4권2호
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• pp.1-14
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• 1989

There is increasing concern that depletion of the ozone layer may have important health consequences. Each $1\%$ decline in ozone concentration is expected to cause a $2\%$ increase in ultraviolet radiation this in turn has been suggested to lead to up to a $4-6\%$ increase in certain kinds of skin cancer. In Colorado state, malignant melanoma patients increased form 7.4 cases per 100,000 to 12.6 per 100,000 in the general population between 1979 and 1985. In Australia, 4,000 new melanomas are diagnosed each year and 800 people die every year from melanoma. Strong international controls CFCs production are necessary to lower the destruction of ozone in the stratosphere. Only then will the increase in ultraviolet radiation to the skin be halted and the incidence and mortality from melanomas be reduced.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권2호
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• pp.1-9
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• 2015

Groundwater has been a very precious resource for human life and economic development in the world. With increasing population and food demand, the groundwater use especially for agriculture is largely elevated worldwide. The very much large groundwater use results in depletion of major aquifers, land subsidences in many large cities, anthropogenic groundwater contamination, seawater intrusion in coastal areas and accompanying severe conflicts for water security. Furthermore, with the advent of changing climate, securing freshwater supply including groundwater becomes a pressing and critical issue for sustainable societal development in every country because prediction of precipitation is more difficult, its uneven distribution is aggravating, weather extremes are more frequent, and rising sea level is also threatening the freshwater resource. Under these difficulties, can groundwater be sustaining its role as essential element for human and society in the near future? We have to focus our efforts and wisdom on answering the question. Korean government should increase its investment in securing groundwater resources for changing climate.