• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.31 no.7
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• pp.65-70
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• 2002

지구의 오존층을 보호하기 위한 몬트리올 의정서가 1987년 채택된 이후 오존층 파괴물질의 사용이 점차 감소되고 있다. 선진국의 경우 1995년 말부터 CFC냉매의 생산을 전폐하였고, HCFC냉매의 경우는 2020년 전폐를 목표로 대체냉매를 이용한 응용 기술개발 및 제품 생산이 진행되고 있다. 가정용 냉장고 및 차량용 에어컨에는 R-12의 대체냉매로 R-134a가 도입되었으며, 유럽을 중심으로 냉장고에는 HC계 냉매인 R-600a도 대체냉매로 사용되고 있다. 가정용 에어컨에는 혼합냉매인 R-407c 와 R-410a가 R-22 냉매를 대체하여 적용되고 있다. 그러나 현재, CFC및 HCFC 대체 냉매로 많이 사용되고 있는 HFC계 냉매도 지구 온난화 지수가 대단히 큰 문제를 가지고 있다. 1997년 채택된 교토의 정서에는 HFC계 냉매가 온실효과가 가스 배출규제물질에 포함되어 있다. 이에 따라서 오존층의 파괴지수가 영이고 지구온난화지수도 거의 없는 자연냉매가 주목을 받게 되었으며, 자연 냉매의 하나인 이산화탄소 ($CO_2$R744) 냉매의 응용기술 및 제품개발 연구가 선진국을 중심으로 폭넓게 진행되고 잇다. 본고에서는 $CO_2$냉매의 일반적인 특성을 간단히 소개하고 일본에서 진행되고 있는 $CO_2$냉매를 적용한 급탕시스템의 제품개발 및 시장현황에 대해서 기술하기로 한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.4
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• pp.286-296
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• 1991

The thermodynamic properties of R134a, the prospective R12 alternative, have been computerized using Martin-Hou equation of state and the coefficients given by Willson-Basu. Several experimental results in literatures for PVT data, saturated vapor pressure, saturated liquid density are compared with the calculated results to investigate the accuracy. The average deviation (max. deviation) is 0.13% (0.25%) for saturated liquid density, 0.25% (0.8%) for PVT data. Thermodynamic properties, enthalpy, entropy are compared with the NIST's. The maximum percent difference is 3% for saturated liquid enthalpy, 1.5% for saturated vapor enthalpy, 4% saturated liquid entropy, and 0.7% for saturated vapor entropy. Correction of W-B's coefficients and inclusion of the sixth term of M-H EOS for improvement of accuracy are recommended. R134a and R12 are compared with respect to refrigeration performance. COP's are different from each other within 3%. Refrigeration effect of R134a is superior to that of R12 but refrigeration capacity of R134a is inferior to that of R12 because the volumetric efficiency of the system using R134a is lower than that of the system using R12.

• Journal of Pharmacopuncture
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• v.3 no.2
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• pp.233-244
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• 2000

After observing a patient diagnosed with Progressive Muscular Dystropies from the August, 31, 2000 to the January, 2001, the following results are obtained. Method and Result: Under our assumption that the Korean Bee Venom Therapy is a good method to treat Progress Muscular Dystropies. Korean Bee Venom Therapy was applied on the following acupuncture points: BL23(Shinsu:腎兪), BL26(Guanyuanshu:關元兪), ST36(Chok-Samni:足三里), LI4(Hapkok:合谷), LV3(Taechung:太), SP10(Hyolhae:血海), SI9(Sojang-Kyonjong:貞). In addition CFC(Carthami Flos;紅花: and Cervi Pantotrichum Cornu;) Herbal-Acupuncture is also treated on the other acupuncture points. For herbal medication was given to the patient based on the Sasang Constitution, Taeyangin Ogapijangchuk-tang. Following these treatments in this case of Progressive Muscular Dystropies, the skeletal muscle functions made remarkable improvement. Conclusion: Based on the clinical results, traditional Korean Medical treatment is believed to be effective for treating Progressive Muscular Dystropies, and further studies should be conducted to provide more valuable information.

• Membrane Journal
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• v.5 no.2
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• pp.81-88
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• 1995

Separation performance was measured for the disc plate and frame type reverse osmosis module using NaCl and sucrose solutions. An analysis of membrane performance was done following the equations proposed by Kimura-Sourirajan[8]. The membrane permeability was $2.17 \times 10^{-6}$(gmol/$cm^2$-sec-bar) and independent of operating pressure. The effect of concentration polarization for sucrose solution was higher than that of NaCl. Permeation flux for sucrose solution above 40 bar was decreased as operating pressure was increased. Solute rejection for NaCl solution was decreased, but that of sucrose was increased as operating pressure was increased.

• Journal of Hydrogen and New Energy
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• v.14 no.2
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• pp.105-113
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• 2003

The pyrolysis for production of hydrogen and high quality carbon black from natural gas were studied. The reactivities in tubular reactor and FVR(free volume reactor) for the methane pyrolysis were compared, in order to prevent the formation of undesirable carbon product such as pyrocarbon, the FVR was designed. The hydrogen yield and the formation of carbon black from methane pyrolysis in this reactor were investigated at temperature range between 1443 and 1576K. From the result of TEM (transmission electron microscopy) analysis, it was confirmed that the CFC(catalytic filamentous carbon) was formed without pyrocarbon.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.10
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• pp.895-900
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• 2004

With the phaseout of CFC and HCFC refrigerants, refrigeration and heat pump systems must be redesigned to match and improve system performance with alternative refrigerants. A generalized flow model for predicting mass flow rate through short tube orifices is derived from a power law form of dimensionless parameters generated by Pi-theorem. The database for developing the correlation includes extensive experimental data for R12, R22, R134a, R407C, R410A, and R502 from the open literature. The correlation yields an average deviation of $0.3\%$ and a standard deviation of $6.1\%$ based on the present database. In addition, rating charts for predicting refrigerant flow rate through short tube orifices are generated for R12, R22, R134a, R407C, R410A, and R502.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.12
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• pp.1132-1138
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• 2005

Recently, production and use of freon substances are restrained due to depletion of ozone layer and global warming. In this aspect of environmental problems, the best solution is to use the natural refrigerant such as ammonia. Thus, this study is to find the optimal operating conditions by comparing the performance between the shell and tube type and shell and disk type heat exchangers using the ammonia refrigerant, and to verify the superiority of the shell and disk type heat exchanger that is not used in field of refrigeration and air conditioning. Finally, this study shows that the shell and disk type heat exchanger is applicable to the ammonia refrigeration system, and this system minimizes the refrigerant charge and installation space.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.30 no.2
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• pp.121-129
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• 2024

This study aimed to focus on the optimization of the external dimension sizes in the corrugated fiberboard cartons (CFCs) for exporting agricultural products. The commercial CFCs of current fresh produces such as paprika, Asian pear, melon, sweet potato, and oriental melon for export were used for this study. The guidelines of the minimum internal dimensions of the refrigerated reefer container, the dimensions of pallets, and the maximum load height of a stack were referred to KS T ISO 668, KS T 1372, and the Container Handbook by the German Insurance Association, respectively. These principles were selected as a ground rule for the external dimensions of CFCs. Package layout design programs of ArtiosCAD and Cape Pack software were used to confirm the box stacking patterns and revise the external dimension of CFCs. The final external dimensions of each CFC were revised from 5 to 30 mm compared to its original dimensions. The maximum load of each stacking box per pallet has been increased from 0.0 to 12.5% compared to its original load.

• Journal of Acupuncture Research
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• v.18 no.3
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• pp.227-238
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• 2001

Objective : There was no report on the treatment of Fascioscapulohumeral (FSH) Muscular Dystrophy by Oriental medicine. But the treatment conducted on the patient admitted to the Sangji Oriental Medicine Hospital from January 9, 2001 to February 23, 2001, a significant treatment result was yielded and would like to suggest treatment plan for the future treatments. Methods : Under the assumption that Korean Bee-Venom Therapy may be affective for treating FSH Muscular Dystrophy, the following points were administered : SI10(노유), SI11(天宗), BL23(腎兪), BL26(關元兪), ST36(足三里), LI4(合谷), Liv3(太衝), SI9(肩貞). CFC(Carthami Flos;紅花 and Cervi Pantotrichum Cornu;鹿茸) herbal extract was treated on the other acupuncture points. Sa-Am(Four needle technique) Acupuncture (tonifying SI5 and ST42, sedating GB41 and ST43) was done every day. For herbal medicine, TaeEumIn ChoWiSeungChung-Tang was given based on the constitutional diagnosis. Results : After 7 weeks of treatment, a remarkable improvement was made for facial muscular movement and muscular strength of the scapular and another regions. Conclusions : 1. Significant improvement in the muscular strength for the case of FSH Muscular Dystrophy was obtained with through Korean Bee-Venom Therapy, Four needle technique, and herbal medication. 2. For progressive muscular dystrophy, it is necessary to practice muscular strength recovery exercise in conjunction with Korean Bee-Venom Therapy. 3. Although this case yielded favorable result, further observation and study must be made to concretely prove the effectiveness of Korean Bee-Venom Therapy for treating muscular dystrophies.

• Journal of Hydrogen and New Energy
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• v.13 no.1
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• pp.3-12
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• 2002

In this study, it achieved life cycle assessment to estimate environmental performance for naphtha steam reforming that account for the production over 50% of total hydrogen output. Although hydrogen dosen't emit air emissions, especially, $CO_2$, a large of $CO_2$ is emitted in hydrogen production process. In the result of this study, it ascertained the truth that $CO_2$ is emitted at the rate of $6.3kg/kgH_2$ and that result from steam reforming reaction and use of fossil fuel in hydrogen manufacturing process. Above all, 57% of total $CO_2$ emissions is emitted in process of steam reforming of naphtha and so it knew that the principle of steam reforming is key issue in aspect to environment. Also, it compared hydrogen by fuel of fuel cell vehicle with gasoline fuel of general gasoline vehicle to analyze relative environment of hydrogen for fossil fuel during the life cycle. As the result, it might be difficult in improvement of environment because $CO_2$ emissions during the hydrogen manufacturing process is nearly the same with that during the use of gasoline.