• Journal of Biosystems Engineering
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• v.22 no.1
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• pp.59-67
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• 1997

An experimental apparatus was developed for the rapid determination of thermal conductivity by transient probe method. The theoretical basis for transient probe method has been investigated. The mathematical model for this method is the Carslaw and Jaeger model which is used perfect line source theory. The small needle probe which is equipped with thermocouple and heating element is constructed. A software that performs data analysis and acquisition is programmed. The influence of the power dissipated per unit length of the probe has been assessed for glycerin. The result showed no significant correlation between thermal conductivity and power input. Determination made with this experimental apparatus were found to agree well with the recommended thermal conductivity data.

• Economic and Environmental Geology
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• v.32 no.1
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• pp.113-121
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• 1999

Coal is both source rock and reservoir rock for the coalbed gas. Coalbed gas. Coalbed gas is predominantly methane and has a heating value of approximatly 1000 BTU/$ft^3$. Most of methane is stored in the coal as a monomolecular layer adsorbed on the internal surface of the coal matrix. The amount of methane stored in coal is related to the rank and the depth of the coal. THe higher the coal rank and the deeper the coal seam is presently buried, the greater its capacity to hold gas. Most of Korean Coal is anthracite or metaanthracite, Ro. 3.5~5.5%, and total reserves are 1.6 billion metric tons. The domestic demand for coal was drastically decreased and the rationalization policy carried out from 1987 on coal industry. Now that a large number of coal mines was closed only a few mines continued to produce not more than 5 million tons for year. It is therefore recommended to formulate a strategy to explore and exploit the resources of coalbed methane in Korea.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.2
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• pp.105-111
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• 1992

The characteristics of suspended particulate matters(dust) in Seoul had been studied. The effects of various environmental factors, such as passengers, motor vehicles, wind velocity, wind direction, temperature and humidity were examined during the study period. It was shown that the dust emission occurred through the heating was the major source, and the contribution of passengers and motor vehicles was relatively negligible during the night. It was also revealed that the number concentration between $0.5{\mu}m$ and $2.0{\mu}m$ was increased due to the attachment among the dusts and mists by the increased humidity during the night. Considering the fact that the particles larger than $2{\mu}m$ take the most part of weight concentration, it was suggested that the PM-10 method which considered respirable particle as a weighting factor should be adapted in the evaluation air quality.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.25-25
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• 2014

박막의 제조는 많은 연구의 기초가 되는 시편을 만드는 과정으로, 현대의 과학기술 연구개발에서 매우 중요한 공정의 하나이다. 그러나 박막의 제조는 제조하는 사람의 숙련도나 장치에 의존하는 경우가 많고 경우에 따라서는 원하는 특성의 박막을 제조하기 어려운 경우도 많다. 그러다보니 경험이 없는 연구자의 경우는 때때로 까다로움과 번거로움을 느끼게 되며, 안정된 공정을 찾기까지 많은 시간을 소비 하게 된다. 특히 부적절한 증발방법의 선정에 따른 실험 결과는 경제적인 손실을 초래할 뿐만 아니라 실험하는 사람을 좌절시키는 가장 큰 요인이 되어왔다. 본 논문에서는 박막 제조에 널리 이용되는 저항가열 및 전자빔 증발원을 이용하여 다양한 물질에 대한 증발특성을 조사하고 그 결과를 발표하고자 한다.

• Macromolecular Research
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• v.11 no.2
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• pp.87-91
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• 2003

Thermal decomposition reactions of polystyrene using a new heating medium were carried out by a batch system at 190-280 $^{\circ}C$ to clarify the manner in which decomposition is initiated. Polystyrene obtained from a commercial source and low molecular weight compounds obtained from the thermal decomposition were analyzed by GC, GPC, IR, $^{13}$ C-NMR and GC-MS. The main chain underwent virtually no change by heat application. Polystyrene underwent decomposition below its molding temperature and the major decomposition products were 2,4,6-triphenyl-1-hexene (trimer), 2,4-diphenyl-1-butene(dimer) and styrene (monomer). Ethylbenzene, propylbenzene, naphthalene, benzaldehyde, biphenyl and 1,3-diphenylpropane were detected as minor products. This paper presents a new method for examining the decomposition of polystyrene at low temperature into volatile low molecular weight compounds.

• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.93-102
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• 2014

The aim of this study is to analyze the influence of various factors on energy consumption of apartment buildings. Energy consumption data of the Green Together, integrated building energy management system maintained by the government were used, and end-use and primary energy consumption data of 2012 were analyzed for 181 apartment complexes completed between 2004 and 2011 in Seoul. Energy consumption by use, source and heating type were analyzed. Then, energy consumption trends were analyzed and suggested according to energy efficiency ratings, number of households, areas for exclusive use, number of floors, core types, building types, orientations and completion years.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.45-54
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• 2003

For cooling of double effect absorption heat pump system of solar heating source, analysis of thermodynamic design data has been done to find the property of Libr-water + ethylene Glycol mixture for working fluid by computer simulation. Derived thermodynamic design data, enthalpy based coefficient of performance and flow ratio for possible combinations of operating temperature for water - LiBr and Ethylene Glycol mixture ($H_2O$ : CHO ratio 10:1 by mole) by computer simulation are done. The obtained results, COP and mass flow ratio of the water - lithium bromide - ethylene glycol system, are compared with data for the water-Libr pair solution.

• Elastomers and Composites
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• v.53 no.2
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• pp.75-79
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• 2018

ZnS:Mn-glycine (ZnS:Mn-Gly) nanocomposites were synthesized by capping ZnS:Mn nanocomposites with glycine. Zinc sulfate heptahydrate ($ZnSO_4{\cdot}7H_2O$), glycine ($C_2H_5NO_2$), manganese sulfate monohydrate ($MnSO_4{\cdot}H_2O$), and sodium sulfide ($Na_2S$) were used as the source reagents. $ZnS:Mn-Gly-C_{60}$ nanocomposites were obtained by heating the ZnS:Mn-Gly nanocomposites and fullerene ($C_{60}$) at a 2:1 mass ratio in an electric furnace at $700^{\circ}C$ for 2 h. X-ray diffraction (XRD) was used to characterize the crystal structure of the synthesized nanocomposites. The photocatalytic activity of the $ZnS:Mn-Gly-C_{60}$ nanocomposites was evaluated, via the degradation of brilliant green (BG) dye under 254 nm irradiation, with a UV-vis spectrophotometer.

• Asian Journal of Atmospheric Environment
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• v.1 no.1
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• pp.14-18
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• 2007

The Korean government enacted the "Special Law for Improving Air Quality of Metropolitan Area" in 2003. According to this plan, Korean government plan to lower the concentrations of $PM_{10}$ and $NO_x$ to $40{\mu}g/m^3$ and 22 ppb, respectively, by 2014. In this study, we analyze emission reduction strategies to lower their concentration. Emission reduction for the supply of mass energy and regenerative energy are compared with several scenarios. According to the results, 713 t/y of $NO_x$ and 165 t/y of $PM_{10}$ will be reduced by enhancing the number of households supplied by local heating and air conditioning. And also 5 t/y of $PM_{10}$ and 312 t/y of $NO_x$ will be reduced by replacing conventional energy with solar energy by 2014.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.4
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• pp.552-558
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• 1999

Ventilation of the marine engine room is very important for the health of the workers as well as the normal operation of machines. To find proper ventilation conditions of this engine room numerical simulation with a standard k-$\varepsilon$model was carried out. In the present study the marine engine room is considered as a closed space with a heat source and forced ventilation ducts. The injection angle of air supply is found to be important. Injection with a downward angle depresses recirculation flow causing a strong stream in the wider space of the room Ventilation and removal of the released heat are promoted with this pattern, There is a possibility of local extreme heating at the upper surface of the engine when supply and exhaust ports of air are in bilateral symmetry.