• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1222-1225
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• 1997

A gaseous oxygen detector has been developed in a configuration of Pd-$SnO_x$-$Si_3N_4$-$SiO_2$-Si-Al with highly resistive $SnO_x$ layer as the oxygen adsorptive element. In this paper, we present the characteristics of the device in response to oxygen adsoption/desorption under applied d.c. bias. Experimental results showed that the oxygen adsorptive response by the device was reduced significantly under a positive gate bias, for all experimental regions of $O_2$ partial pressure. On the other hand, the application of a negative gate bias increased the device's adsorptive response of oxgyen. A device model concerning this electroadsorption/desorption behavior of the device is provided.

• 지구물리와물리탐사
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• 제7권1호
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• pp.25-32
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• 2004

We have carried out laboratory measurements of P-wave velocity and deformation strain during $CO_2$ injection into a porous sandstone sample, in dry and water-saturated conditions. The rock sample was cylindrical, with the axis normal to the bedding plane, and fluid injection was performed from one end. Using a piezoelectric transducer array system, we mapped fluid movement during injection of distilled water into dry sandstone, and of gaseous, liquid, and supercritical $CO_2$ into a water-saturated sample. The velocity changes caused by water injection ranged from $5.61\;to\;7.52\%$. The velocity changes caused by $CO_2$ injection are typically about $-6\%$, and about $-10\%$ for injection of supercritical $CO_2$, Such changes in velocity show that the seismic method may be useful in mapping $CO_2$ movement in the subsurface. Strain normal to the bedding plane was greater than strain parallel to the bedding plane during $CO_2$ injection; injection of supercritical $CO_2$ showed a particularly strong effect. Strain changes suggest the possibility of monitoring rock mass deformation by using borehole tiltmeters at geological sequestration sites. We also found differences associated with $CO_2$ phases in velocity and strain changes during injection.

• 설비공학논문집
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• 제22권10호
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• pp.697-703
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• 2010

In recent semiconductor manufacturing clean rooms, air washers are used to remove airborne gaseous contaminants from the outdoor air introduced into a clean room. Meanwhile, there is a large amount of exhaust air from a clean room. From an energy conservation point of view, heat recovery is useful for reducing the outdoor air conditioning load required to maintain a clean room. Therefore it is desirable to recover heat from the exhaust air and use it to cool or heat the outdoor air. In the present study, numerical analysis was conducted to evaluate the recovered heat of an exhaust air heat recovery type air washer system, which is the key part of an energy saving outdoor air conditioning system for semiconductor clean rooms. The present numerical results showed relatively good agreement with the available experimental data.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.844-849
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• 2008

In recent semiconductor manufacturing clean rooms, in order to improve clean room air quality, air washers are used to remove airborne gaseous contaminants such as $NH_3$, SOx and organic gases from outdoor air introduced into clean room. Meanwhile, there is a large quantity of exhaust air from clean room. From the energy saving point of view, heat recovery is useful for the reduction of air conditioning energy consumption for clean room. Therefore it is desirable to recover heat from the exhaust air and use it to reheat the outdoor air. However, so far there have not been sufficient studies of analyzing the comparison of the amounts of energy consumption and saving. In the present study, an experiment was conducted to investigate the energy consumption and heat recovery of a fin-coil type air washer system for semiconductor manufacturing clean rooms.

• 대한화학회지
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• 제17권5호
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• pp.353-356
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• 1973

광물안의 기체불순물에 관한 연구는 특이한 파괴분석법(질량분석계를 사용)에 의하여 발전되어 왔다. 시료의 분쇠는 영구용 질량분석계의 고진공내에서 텅크스텐 카아바이드(tungsten carbide)로된 분쇠기로 행하여 졌다. 사용한 질량분석계의 측정감도는 표준상태에서 약 $10^{-10}cc$였다. 이 보문은 미국 죠지아주 라보니아 부근에서 채집된 석류석에 대한 위의 분석법에 의한 기체조성의 확인 및 결정을 보고하는 것이며 그 조성들은 $N_2$, $H_2$, $O_2$, $H_{2}O$, $CO_2$, CO, $CH_4$등이 있다.

• Nuclear Engineering and Technology
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• 제40권7호
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• pp.581-592
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• 2008

In this study, a conceptual pyroprocess flowsheet has been devised by combining several dry-type unit processes; its applicability as an alternative fuel cycle technology was analyzed. A key point in the evaluation of its applicability to the fuel cycle was the recovery yield of fissile materials from spent fuels as well as the proliferation resistance of the process. The recovery yields of uranium and transuranic elements (TRU) were obtained from a material balance for every unit process composing the whole pyroprocess. The material balances for several elemental groups of interest such as uranium, TRU, rare earth, gaseous fission products, and heat generating elements were calculated on the basis of the knowledge base that is available from domestic and foreign experimental results or technical information presented in open literature. The calculated result of the material balance revealed that uranium and TRU could be recovered at 98.0% and 97.0%, respectively, from a typical PWR spent fuel. Furthermore, the anticipated TRU product was found to emit a non-negligible level of $\gamma$-ray and a significantly higher level of neutrons compared to that of a typical plutonium product obtained from the PUREX process. The results indicate that the product from this conceptual pyroprocessing should be handled in a shielded cell and that this will contribute favorably to retaining proliferation resistance.

• 한국재료학회지
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• 제3권5호
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• pp.451-458
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• 1993

베아링강(AISI S2100) 위에 TiCi/sub 4/, N/sub 2/,H/sub 2/,그리고 Ar의 기체혼합계를 이용하여 플라즈마화학증착법으로 내마모 TiN증착층을 얻었다. 증착된 TiN층 내의 잔류 CI에 의한 결정성, 미소경도, 접착력, 그리고 마모특성에 대해 연구하였다. TiN 중착층은 좋은 내마모성을 가지고 있었으며, TiN의 기계적 특성은 잔류CI함량이 증가할때 나빠졌다. 마모측정결과 마모면의 trailing edge에 인장응력이 걸려 많은 crack이 관찰되엇다.

• 한국대기환경학회지
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• 제21권1호
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• pp.49-62
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• 2005

Lake Paldang is a main resource of drinking water for 20 million people in the greater Seoul area. Dry deposition amounts of nitrogen and sulfur were estimated for three typical days in each season over the watershed of Lake Paldang. Models- 3/CMAQ (Community Multiscale Air Quality) and MM5 (Mesoscale Model) were used to predict air quality and meteorology, respectively. Aerosols as well as gaseous pollutants were considered. Nitrogen was mainly deposited in the form of HNO, while most of sulfur was deposited in the form of SO$_2$. Contribution of secondary pollutants was the largest in fall since they were transported from the greater Seoul area. However, contribution of secondarily-formed particulate pollutants to the nitrogen deposition was the largest in winter because semi-volatile ammonium nitrate favors lower temperature. Annual deposition amounts of nitrogen and sulfur were 37% and 26% of their emission amounts, respectively, over the watershed of Lake Paldang. Higher value of the nitrogen deposition showed a more influence of pollutants emitted in the greater Seoul area.

• Journal of Korean Society for Atmospheric Environment
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• 제9권E호
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• pp.373-381
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• 1993

To understand the human exposure levels of volatile halogenated hydrocar-bons in ambient air, a new rapid and convenient analytical method for determination of the compounds in gaseous phase was evaluated and established. The method is based upon passsive diffusion to personal sampler containing adsorbent and solvent extraction followed by purge trap/ on-column cryof-ocusing method. A new method needs no special instrumentation for gas collection because it is based upon the passive diffusion principle. The typical chromatogram obtained in this study proved that rapid and simultaneous determination of target analytes was possible with good resolution. The developed method was successfully applied to determine the volatile halogenated hydrocarbons in indoor air and the values obtained by this new method were compared with those by direct suction method. The concentration of carbon tetrachloride, 1,1,2-trichloroethylene, chloroform showed the values below 400$\mug/m^3$ except the maximum of 1,513$\mug/m^3$ of chloroform. 1,1,1-Trichloroethane showed approximately 1,000 to 5,000$\mug/m^3$ range of diurnal fluctuation in indoor air.

• 한국대기환경학회지
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• 제6권2호
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• pp.183-191
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• 1990

To check the possible transportation of gaseous air pollutants with the particles of yellow sand in the movement of air masses during the Yellow Sand Phenomenon, the concentrations of such air pollutants as TSP, $SO_2, CO, NO_x, O_3 and N-CH_4$, and wind wpeed were measured during the Yellow Sand Phenomenon (April 8 $\sim 10, 1990) and they were compared with those during the normal times in Korea. Meanwhile dust color of the samples during the Yellow Sand Phenomenon was the color of sand, that during the normal times was dark-brown. The concentrations of dusts; water soluble components, and metallic components of soil-originated elements during the Yellow Sand Phenomenon were higher than those during the normal times. While the metallic components in the dusts during the Yellow Sand Phenomenon were from soil-originated elements, those during the normal times were of both soiloriginated and sea-originated elements. The change of hourly concentrations of air pollutants showed bi-modal distribution during the two periods. Generally, the concentration levels of air pollutants during the Yellow Sand Period were higher than those during the normal times. Although similarity was observed in the primary sources, differences were observed in the dynamics of the secondary sources due to chemical reactions of the air pollutants during the two periods.