• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.04a
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• pp.150-151
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• 2006

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.275-276
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• 2010

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.275-276
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• 2000

소각로에서 배출되는 다이옥신은 위해성 문제로 논란이 계속되고 있으며 현재 국내 도시 소각로의 경우 배출 기준치를 만족시켜야 하는 둥의 규제를 받고 있다. 또한 앞으로는 사업장소각로에서도 다이옥신 정기 측정이 의무화되는 등 배출원에서의 다이옥신 관리가 점차 더 강화될 예정이다. 이처럼 소각로에서 배출된 다이옥신은 대기 중 확산 및 이송과정에서 건·습식 침적과정을 통해 각 환경매체로 재분포되어 생물체에 농축 및 최종적으로는 인체로 유입되기도 한다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.111-113
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• 2006

• Journal of Radiation Protection and Research
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• v.23 no.4
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• pp.251-257
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• 1998

A diffusion model of radioactive gaseous effluents is improved to apply for domestic nuclear power plants. Up to now, XOQDOQ computer code package developed by U. S NRC has been used for the assessment of radioactive plume dispersion by normal operation of domestic nuclear power plants. XOQDOQ adopts the straight-line Gaussian plume model which was basically derived for the plane terrain. However, since there are so many mountains in Korea, the several shortcomings of XOQDOQ are improved to consider the complex terrain effects. In this work, wind direction change is considered by modifying the wind rose frequency using meteorological data of the local weather stations. In addition, an effective height correction model, a plume reduction model due to plume penetration into mountain, and a wet deposition model are adopted for more realistic assessments. The proposed methodology is implemented in Yongkwang nuclear power plants, and can be used for other domestic nuclear power plants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.644-650
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• 2021

This study characterized the reforming of methane with carbon dioxide, which is a major cause of global warming. The methane decomposition reaction with carbon dioxide was carried out using transition metal catalysts. The reactivity of tin was lower than that of a transition metal, such as nickel and iron. Most of the decomposition reaction occurred in the solid state. The melting point of tin is 505.03 K. Tin reacts in a liquid phase at the reaction temperature and has the advantage of separating carbon produced by the decomposition of methane from the liquid tin catalyst. Therefore, deactivation due to the deposition of carbon in the liquid tin can be prevented. Methane decomposition with carbon dioxide produced carbon monoxide and hydrogen. Ni was used to promote the catalyst performance and enhance the activity of the catalyst and lifetime. In this study, catalysts were synthesized using the excess wet impregnation method. The effect of the reaction temperature, space velocity was measured to calculate the activity of catalysts, such as the activation energy and regeneration of catalysts. The carbon-deposited tin catalyst regeneration temperature was 1023 K. The reactivity was improved using a nickel co-catalyst and a water supply.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.6
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• pp.693-703
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• 2008

The important source of the mercury in water-column is the influx of atmosphere mercury, via dry and wet deposition. In this study, wet deposition of mercury was estimated to be $14.56{\mu}g/m^2$ during 15 months at the Lake Soyang, which is a little higher than those observed in the several rural US Mercury Deposition Network (MDN) sites with similar precipitation depth. The mercury concentration in precipitation did not show a positive correlation with atmospheric RGM (reactive gaseous mercury) concentration, while maintaining good correlation with atmospheric $PM_{2.5}$ at Soyang Dam. This result suggests that the contribution of particulate Hg to the total Hg wet deposition should be more significant than that of RGM. In this study, both precipitation depth and precipitation type affected the amount of wet deposition and the concurrent mercury levels in precipitation. There was generally an inverse relationship between precipitation depth and Hg concentration in precipitation. Precipitation type was another factor that exerted controls on the Hg concentration in precipitation. As a result, the highest concentration of Hg was observed in snow, followed by in mixture (snow+rain) and in rain.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.4
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• pp.302-308
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• 2000

Stable amorphous calcium carbonate were synthesized from the serial work for the synthetic conditions such as concentration of solution, reaction temperature, aging time and pH of mother liquor. By using this as a precusor, calcite, aragonite and vaterite crystal particles were obtained in the water from adequate crystallization conditions. Furthermore, characterization for flourescence were performed by using crystals which were crystallized from the Sn dopped amorphous calcium carbonate. Calcite showed the most intensive emission and the center of emission wavelength was 464 nm with pure blue color. Calcite is expected to be used as phosphor for flourescent lamp because the maximum emission intensity was obtained from the excitation with 255 nm wavelength.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.89-89
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• 2009

높은 소수반송자 수명(life-time)을 가지는 고품위 실리콘 기판은 고효율 실리콘 이종접합 태양전지 제작을 위한 중요 요소 기술 중 하나이다. 본 연구에서는 n-type c-Si 기판을 이용한 고효율 실리콘 이종접합 태양전지제작을 위해 hot water oxidation(HWO) 공정을 이용하여 고품위 실리콘 기판을 제작하였다. 실리콘 기판의 특성 분석은 Qusi-steady state photoconductance (QSSPC)를 이용하여 소수반송자 수명을 측정하였으며, 기판의 면저항 및 wetting angle을 측정하여 공정에 따른 특성변화를 분석하였다. Saw damage etching 된 기판을 웨이퍼 표면으로부터 particle, 금속 불순물, 유기물 등의 오염을 제거하기 위해 $60{\sim}85^{\circ}C$로 가열된 Ammonia수, 과산화수소수($NH_4OH/H_2O_2/H_2O$), 염산 과산화수소수($HCL/H_2O_2/H_2O$) 및 실온 희석불산(DHF) 중에 기판을 각각 10분 정도씩 침적하여, 각각의 약액 처리 후에 매회 10분 정도씩 순수(DI water)에서 rinse하여 RCA 세정을 진행한 후 HWO 공정을 통해 기판 표면에 얇은 산화막 을 형성시켜 패시베이션 해주었다. HF를 이용하여 자연산화막을 제거시 HWO 공정을 거친 기판은 매끄러운 표면과 패시베이션 영향으로 기판의 소수 반송자 수명이 증가하며, 태양전지 제작시 접촉저항을 감소시켜 효율을 증가 시킬수 있다. HWO 공정은 반응조 안의 DI water 온도와 반응 시간에 따라 life-time을 측정하여 진행하였으며, 이후 PE-CVD법으로 증착된 a-Si:H layer 및 투명전도 산화막, 금속전극을 증착하여 실리콘 이종접합 태양전지를 제작하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.6
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• pp.288-292
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• 2009

Hydrophobic/hydrophilic patterned substrates were fabricated on a glass substrate by a liquid phase deposition (LPD) method. Hydrophobic surface was obtained by modifying ZnO thin films with a rough surface using a fluoroalkyltrimethoxysilane (FAS) and hydrophilic surface was prepared by decomposing FAS on an exposed to UV light. The hexagonal ZnO rods were perpendicularly grown by LPD method on glass substrates with a ZnO seed layer. The diameter and thickness of hexagonal ZnO rods were increased as a function of increases of immersion time. The surface morphology, thickness, crystal structure, transmittance and contact angle of prepared ZnO thin films were measured by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible spectrophotometer (UV-vis) and contact angle measurement. Hydrophilic ZnO thin films with a contact angle of $20^{\circ}{\sim}30^{\circ}$ were changed to a hydrophobic surface with a contact angle of $145^{\circ}{\sim}161^{\circ}$ by a FAS surface treatment. Prepared hydrophobic surface was pattered by an irradiation of UV light using shadow mask with $300\;{\mu}m$ or 3 mm dot size. Finally, the hydrophobic surface exposed to UV light was changed to a hydrophilic surface.