• Journal of environmental and Sanitary engineering
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• v.11 no.1
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• pp.57-61
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• 1996

This study was to decompose carbon tetrachloride and CFC with pyrolytic incineration unit because of prohibition of their usage sooner or later. We have investigated heating value and temperature versus decomposing rate, removal of $Cl_2$ and dust in the flue gas, The results obtained were as follows; 1. In combustion condition to decompose $CCl_4$ heating value was 3,300Kcal/Kg, retention time was 2,0 sec. incinerator exit temperature was $950^{\circ}C$. 2.The removal of HCI and $Cl_2$ in flue gas used NaOH as reagent, then molar ratio o of $Na^+/Cl^-$ was 1.07. 3. NaCI of dust component was more than 90 %, 2 stage venturi scrubber was used to remove dust, then removal rate of dust was 99% over at L/G of $1.7Vm^3$

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1114-1124
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• 2001

The application of carbon dioxide as an attractive natural working fluid in air cooling and heating system is increasingly important in view of the CFC substitution problem. The thermal performance of compact evaporator was analyzed using section-by-section method. The effects of the two-dimensional nonuniformity of air flow through the evaporator is presented. The detrimental effect of the aid flaw nonuniformity on the thermal performance of the evaporator is found to be significant for many typical applications. It is shown that total heat transfer rate of evaporator using $CO_2$ is higher than that using R134a at the simulation conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.196-203
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• 2003

This study was performed to design the optimal block type expansion valve through analyzing the characteristics of the block type expansion valve in automotive air conditioning system using HFC-134a. Because an alternative refrigerant (HFC-l34a) is being used instead of CFC-12 for automotive air conditioning system, newly designed air conditioning components are necessary due to changes in characteristics. The performance tests were accomplished through the test bench, that is manufactured based on the study. And then it was carried out to measure the variation of temperature and pressure at each part of the air conditioning system according to the compressor speed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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• pp.624-632
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• 1999

In order to replace CFC-502 which has been widely used in transportation and low temperature refrigeration system, performance tests using HFC-407A, HFC-404A and HFC-507 have been carried out. Measurements were conducted at two different condensing temperatures of $43.3^{\circ}C$and $54.5^{\circ}C$ for each refrigerant. System performance characteristics and heat transfer characteristics of each refrigerant were obtained at several compressor speeds and evaporating temperatures ranging from$-25^{\circ}C$ to $-10^{\circ}C$ Test results show that the use of tested alternative refrigerants without changing system components offers the potential performance improvement of a refrigeration system.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.471-473
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• 2010

본 논문은 선형회귀(LR: Linear Regression)와 국부적인 방사기저함수 네트워크(RBFN: Radial Basis Function Networks)를 결합한 점진적인 모델(incremental model)의 설계와 관련되어진다. 전형적인 RBFN에 의한 모델링과는 달리, 제안된 방법의 근본적인 원리는 두 단계에 의해 고려되어진다. 첫째, 전체 모델의 설계과정에서 전역적인 모델로써 선형회귀에 의해 데이터의 선형부분을 구축한다. 다음으로, 모델링 오차는 오차가 존재하는 국부적인 공간에서 RBFN에 의해 보상되어진다. 여기서, 오차의 분포로부터 RBFN을 설계하기 위해 컨텍스트 기반 퍼지 클러스터링(CFC: Context-based Fuzzy Clustering)를 통해 정보입자의 형태로 구축되어진다. 실험은 자동차 mpg 연료소비량 예측과 부동산 가격예측문제를 통해 제안된 방법의 우수성을 증명한다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.4
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• pp.68-78
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• 1999

Heat transfer performance is studied for boiling and condensation of R-11 on integral-fin tubes. Nine tubes with trapezoidal integral-fins having fin densities from 748 to 1654fpm and 10,30 grooves and finned tubes with caves of 0.55 and 0.64 mm height respectively are tested. in case of condensation CFC-11 condensates at saturation stat of 32$^{\circ}C$ on the outside surface cooled by inside cooling water flows. And in case of boiling the refrigerant evaporates at a saturation state of 1 bar on the outside tube surface and heat is supplied by hot water which circulates inside of the tube,. The tube having fin transfer coefficient concerns fin tubes with caves show higher valve than low fin tube having find density of 1299fpm and 30grooves. The overall heat transfer coefficient of fin tube with caves is about 5155 W/mK at 2.8m/s of water velocity, The value is abuot 2.7 times higher than plain tube and 1.3 times higher than low fin tube having fin density of 1299fpm and 30 grooves.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.4
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• pp.65-65
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• 1999

Heat transfer performance is studied for boiling and condensation of R-11 on integral-fin tubes. Nine tubes with trapezoidal integral-fins having fin densities from 748 to 1654fpm and 10,30 grooves and finned tubes with caves of 0.55 and 0.64 mm height respectively are tested. in case of condensation CFC-11 condensates at saturation stat of 32℃ on the outside surface cooled by inside cooling water flows. And in case of boiling the refrigerant evaporates at a saturation state of 1 bar on the outside tube surface and heat is supplied by hot water which circulates inside of the tube,. The tube having fin transfer coefficient concerns fin tubes with caves show higher valve than low fin tube having find density of 1299fpm and 30grooves. The overall heat transfer coefficient of fin tube with caves is about 5155 W/mK at 2.8m/s of water velocity, The value is abuot 2.7 times higher than plain tube and 1.3 times higher than low fin tube having fin density of 1299fpm and 30 grooves.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.499-508
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• 2010

This study proposed a life cycle impact assessment index that can indicate the environment-related information of the product in monetary value such that the national geographical, environmental, and social features are fully reflected based on a damage-oriented model. First, the estimation process was classified into characterization, damage assessment, and integration stages considering the six biggest impact categories: resource depletion, global warming, ozone depletion, acidification, eutrophication, and photochemical oxidant creation. Moreover, this study came up with the 16 category endpoints related to the 6 impact categories, and the damage function, to the 4 largest safeguard subjects. The integration indices of finally identified impact categories were KRW 21.8/kg Sb, KRW 6.19/kg$CO_2$, KRW 53,000/kg CFC-11, KRW 13,100/kg $SO_2$, KRW 2,310/kg ${PO_4}^{3-}$, and KRW 3,030/kg $C_2H_4$. Using the results of this research, environmental impacts based on the environmental load generated throughout the entire life cycle of a product can serve as a single index in monetary value; thus enhancing understanding and utilization of the results of life cycle impact assessments.

• Resources Recycling
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• v.27 no.1
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• pp.74-83
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• 2018

This study conducted the Life Cycle Assessment(LCA) on waste rubber recycling technology for recovering rubber product from the waste tires. Environmental impacts were assessed for the five categories of impacts: global warming, resource depletion, acidification, eutrophication, photochemical oxide production, and ozone layer depletion. When recycling 1ton of waste tire containing rubber, global warming impact was 1.77E+02 kg $CO_2-eq.$, resource depletion impact was 1.23E+00 kg Sb-eq., acidification impact was 5.92E-01 kg $SO_2-eq.$, eutrophication impact was 1.23E-01 kg $PO{_4}^{3-}-eq.$, photochemical oxide production impact was 3.42E-01 kg $C_2H_4-eq.$, and ozone layer depletion impact was 1.87E-04 kg CFC11-eq. In terms of overall environmental impacts, carbon, softener and electricity the greatest impact, so it is necessary to compare the environmental impacts of the raw materials to replace carbon and softener, and a method to reduce the filler usage in the process is needed. In addition, it is necessary to improve energy efficiency, change to low-energy sources, and apply renewable energy.

• Clinical and Experimental Pediatrics
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• v.50 no.8
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• pp.757-760
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• 2007

Purpose : Febrile convulsions (FC) were considered to be a benign seizure syndrome that is distinct from epilepsy. But it is thought that children with complex features i.e., partial or prolonged seizures or multiple episodes of FC would bear a higher risk of developing unprovoked seizures. The aim of this study is to look into the relative significance of each criteria that define complex febrile convulsions (CFC) as a predictor of subsequent epilepsy. Methods : All children were retrospectively identified for a febrile seizure through pediatric departments of the Konyang University Hospital. Information was collected from medical records and interviews with parents. Patients with abnormal neurological examinations at presentation were excluded. Results : This study was performed from March 2000 to December 2003. Sixty-three out of 314 children (20.0%) with febrile convulsion fulfilled the criteria for CFC and forty-four children of them have been followed for 12 months or more. Ten of these (23.2%) had unprovoked seizures for 14-62 months (median $34.2{\pm}11.6$ months). The patients with partial FC showed a trend toward a higher risk (57.1%) of developing epilepsy than the patients with multiple or prolonged febrile convulsions (26.7%, 24.1% respectively). Conclusion : We found that the partial feature of febrile convulsion is associated with subsequent epilepsy.