• 설비공학논문집
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• 제21권12호
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• pp.715-732
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• 2009

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.

• 한국지구과학회:학술대회논문집
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• 한국지구과학회 2010년도 춘계학술발표회 논문집
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• pp.90-91
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• 2010

우리나라는 산업화와 도시화의 급속한 발전으로 인한 대기오염물질배출시설, 자동차 통행량, 에너지 사용량의 증가 등으로 대기오염물질배출원의 수와 규모가 증대되어 광역도시를 중심으로 대기질이 악화되고 있다. 특히 우리나라의 수도권대기질은 선진국의 주요 도시에 비해 대기오염 상태가 좋지 않은 것으로 평가됨에 따라 정부는 대기질을 OECD선진국 수준으로 개선한다는 목표를 세우고 있으나, 지역의 대기상태 및 그 동안의 대기질 개선을 위해 이행된 정책의 효율성 측면에서 볼 때 사후적인 규제위주의 농도규제 방식으로는 급증하는 대기오염배출시설의 배출량총량 관리가 어렵고, 지자체별로 개별적인 분산관리로는 광역적으로 이동되는 대기오염물질의 관리가 불가능하다. 또한 대기오염과 상관성이 큰 에너지정책, 산업정책, 도시계획 등 관련 정책과의 통합적 접근이 어렵기 때문에 사전에 이를 예방하는 총량관리가 요구되어 진다. 총량규제란 특정지역의 기상, 지형조건 등을 이용하여 대기환경용량을 산출하고 이를 기초로 지역별 배출허용총량을 할당하여 궁극적으로는 오염원별로 대상오염물질의 삭감량을 정하는 제도로 선진국에서는 대기환경용량을 바탕으로 1970년대부터 사업장을 중심으로 배출농도 규제와 함께 총량규제를 병행 실시하고 있으며, 최근에는 자동차에도 실시하고 있다. 우리나라에서도 대기환경보전법 제9조에서 환경기준을 초과하여 사람의 건강이나 재산, 동식물의 생육에 중대한 위해를 가져올 우려가 있다고 인정되는 경우에는 동 지역 또는 특별대책지역 중 사업장이 밀집되어 있는 구역에 대하여 배출되는 오염물질을 총량으로 규제할 수 있도록 규정하고 있다. 또한, 환경부는 2003년도에 서울, 인천, 경기도내 19개시 지역을 대상으로 대기오염물질의 배출총량을 관리하는 대기오염총량제 실시를 포함한 '수도권대기질개선에관한특별법'을 제정하였고, 현재는 사업장에게 연도별 배출허용총량을 할당하고, 할당량 이내로 오염물질을 배출하도록 관리하는 사업장 대기오염물질총량관리 제도로 시행 중에 있다. 그러나 수도권대기질개선특별대책을 수립하면서 총량관리의 본격 이행 및 배출권 거래제도 도입에 대한 특별법안이 제정되고 부분적으로 시행되고 있으나, 우리나라에 총량관리를 본격 이행하는데 있어서의 필요한 준비여건은 아직 초기 단계이고, 관련 연구의 수행실적 또한 수도권에 제한되어 적은 편이다. 따라서 현재는 총량관리가 수도권에 국한하여 실시되고 있으나, 점차 타 도시까지 광역적으로 확대될 것으로 예상되는 바 이에 필요한 제반 사항들에 대한 조사 분석을 통하여 정책방향을 설정하는 더 많은 연구가 필요할 것이다. 이러한 배경에서 본 연구에서는 대구지역을 대상으로 대기오염농도 및 대기오염물질 배출량에 대한 현황조사를 실시하고, 이를 토대로 고농도가 자주 발생되거나 그러할 가능성이 높은 $NO_X$을 대상으로 대기오염기여도를 평가하고 대기확산모델을 통한 대기환경용량을 산정하였다. 대기오염농도 현황을 살펴본 결과, 대구지역의 대기오염은 $NO_2$, $SO_2$, CO는 전형적인 1차오염물질의 변화경향을 보였으며, $PM_{10}$는 봄철에 황사의 영향을 크게 받는 것으로 나타나 실제 대구지역에서 배출되는 양을 추정하기 힘든 것으로 판단된다. 또한 $NO_2$는 공업, 상업지역에서 $SO_2$와 $PM_{10}$는 공업지역, CO는 상업지역, $O_3$은 교외지역에서 높은 농도를 나타내는 것으로 파악되었다. 대구지역의 대기오염물질 배출량 현황은 CO가 47%, NOX가 43%로 전체 배출량의 90%를 차지하였고, 2005년 이후 $NO_X$는 감소하고 $SO_X$가 증가하는 추세이다. 또한 배출원대분류 중도로 및 비도로이동오염원에서 발생되는 선 오염원이 75%로 대구지역에서 가장 크게 기여하는 것으로 나타났다. ISCST3 대기확산모델을 이용하여 대기환경용량을 산정하기위하여, 먼저 대구지역의 대기환경용량평가는 가시적인 위해성이 높고 개선정책이 용이한 $NO_X$을 대상물질로 선정하였고, 배출량과 오염농도간의 상관도가 0.659로 높은 것으로 판단되어, 배출량을 삭감하였을 때 대기오염농도의 개선이 명확히 나타나는 것을 알 수 있었다. 다음으로, 단위격자 당 한계배출율을 알아내는 작업을 실시하여, 대구지역을 동일하게 장기환경기준 80%수준인 22.4ppb를 만족시키기 위한 한계배출율은 2.23g/s가 필요한 것으로 파악되었고, 산출한 한계배출율을 이용하여 장기환경기준치 80%수준 달성을 목표로 하는 경우의 대기환경용량을 산정하고 실제 배출량과 비교 분석하였다. 그 결과, 대구지역 전체의 환경용량은 약 3만 톤으로 실제 배출량 2만2천 톤에 약 8천 톤 이상의 여유가 있는 것으로 파악되었다. 그러나 구역별로 상이한 차이를 보였으며, 이에 따른 구역별 개선정책이 필요할 것으로 사료된다. 대기환경용량을 파악한 후 단위격자 당 한계배출율을 초과하는 대상 지역을 추출하여 삭감한 결과 초과배출량의 80%를 삭감해야 대구지역 전체에서 50ppb이하 농도가 되는 것을 알 수 있었는데, 실제로 초과배출량의 80%를 삭감하는 것은 어려움이 있다고 판단되어, 대구지역을 동일한 %율로 삭감한 결과 30% 삭감했을 때 50ppb수준을 달성하였고, 50%삭감했을때 2007년 환경기준인 30ppb수준을 달성하였다. 또한 배출원대분류 중 기여율이 높은 도로와 비도로오염원을 50%삭감한 결과 도로이동오염원의 삭감만으로도 상당한 고 배출지역의 농도저감에 효과가 있는 것으로 파악되고, 비도로오염원을 포함하여 삭감하였을 때는 대구지역 전체에서 50ppb이하로 내려가는 것을 볼 수 있었다. 따라서 향후 총량규제의 실시에 맞추어 대구지역의 실제적인 환경용량의 정확한 파악과 고배출지역에 대한 삭감방법에 관한 더 많은 연구가 필요하다고 사료된다. 이 연구 결과는 앞으로 시행될 지역총량규제에 대한 기초적인 방법론으로 활용될 수 있을 것이다.

• 한국식품영양과학회지
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• 제38권3호
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• pp.338-345
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• 2009

미강유(RBO), 팜스테아린(PS), 고올레인산 해바라기씨유(HO)를 기질로 사용하여 24 hr, $65^{\circ}C$의 조건하에 회분식 반응기(batch type reactor)에서 TLIM을 이용한 interesterification을 통해 생성된 저트랜스 쇼트닝의 이화학적 특성을 살펴보았다. DSC 분석결과를 살펴보면, SFC 함량 변화는 commercial shortening과 low-trans shortening(LTS) 간에 거의 유사하게 측정되었고, slip melting point는 각각 35.5, $34.8^{\circ}C$로 나타났다. 지방산 조성 분석 결과, LTS는 전체 지방산 조성의 90% 이상이 C16:0(33.7 wt%), C18:1(45.7 wt%), C18:2(13.4 wt%)로 구성되어 있으며 이 중 트랜스지방산은 시중 유통 쇼트닝보다 3배 이상 적은 0.5 wt%로 미량 검출되었다. Sn-2 position에 위치한 지방산 조성은 C16:0이 36.6 wt%, C18:1이 43.5 wt%로 나타났다. LTS의 주요 TAG 조성으로는 POO, POP, PLO 등으로 나타났고, 반응 전과 반응 후의 TAG 조성을 비교해 보면, OOO와 PPP의 area%는 각각 27.65에서 6.97 area%로, 11.97에서 3.36 area%로 감소한 반면 POO는 15.94에서 29.05 area%로, PLO는 6.44에서 13.05 area%로 증가되었다. ${\alpha},\;{\gamma}\;{\delta}$-Tocopherol 분석 결과 LTS의 total tocopherol은 12.37 mg/100 g, ${\gamma}$-oryzanol 함량은 0.43 mg/100 g을 나타냈으며, total phytosterol 함량은 251.38 mg/100 g으로 나타났다. Commercial shortening과 LTS의 texture analyzer를 통한 hardness 측정 결과, commercial shortening은 157.41 g, LTS는 157.00 g으로 두 시료의 hardness가 비슷하게 측정되었다. LTS의 polymorphic form을 측정하기 위해 x-ray duffraction을 사용하였다. 일반적으로 쇼트닝이나 마가린은 ${\beta}'$형 결정일 때 바람직하다고 여겨지는데, LTS의 분석 결과 ${\beta}$형이 함께 공존하고 있지만, ${\beta}'$형이 우세하게 나타났다.

• 설비공학논문집
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• 제26권12호
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• pp.605-619
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• 2014

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

• 설비공학논문집
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• 제27권7호
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• pp.380-394
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• 2015

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

• 설비공학논문집
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• 제20권12호
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• pp.844-861
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• 2008

The papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during the year of 2007 have been reviewed. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro nano fluid, micropump and fuel cell. Traditional CFD was still popular and widely used in research and development. Studies about fans and pumps were performed in the field of fluid machinery. Characteristics of flow and fin shape optimization are studied in the field of piping system. (2) The research works on heat transfer have been reviewed in the field of heat transfer characteristics, heat exchangers, and desiccant cooling systems. The research on heat transfer characteristics includes thermal transport in pulse tubes, high temperature superconductors, ground heat exchangers, fuel cell stacks and ice slurry systems. For the heat 'exchangers, the research on pin-tube heat exchanger, plate heat exchanger, condensers and gas coolers has been cordially implemented. The research works on heat transfer augmenting tubes have been also reported. For the desiccant cooling systems, the studies on the design and operating conditions for desiccant rotors as well as performance index are noticeable. (3) In the field of refrigeration, many papers were presented on the air conditioning system using CO2 as a refrigerant. The issues on the two-stage compression, the oil selection, and the appropriate oil charge were treated. The subjects of alternative refrigerants were also studied steadily. Hydrocarbons, DME and their mixtures were considered and various heat transfer correlations were proposed. (4) Research papers have been reviewed in the field of building facilities by grouping into the researches on heat and cold sources, air conditioning and air cleaning, ventilation and fire research including tunnel ventilation, flow control of piping system, and sound research with drain system. Main focuses have been addressed to the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies were mostly focused on analyzing the indoor environment in various spaces like cars, old tombs, machine rooms, and etc. in an architectural environmental field. Moreover, subjects of various fields such as the evaluation of noise, thermal environment, indoor air quality and development of energy analysis program were researched by various methods of survey, simulation, and field experiment.

• 대한화장품학회지
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• 제30권3호
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• pp.393-397
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• 2004

L-Carnitine $({\beta}-hydroxy-\gamma-trimethyl-ammoniumbutyric{\;}acid)$은 분자량이 적은 수용성 분자로서 세포 내 지방 대사에서 중요한 역할을 수행한다. 지방산의 운반 분자인 아실-코에이(acyl-CoA)가 미토콘드리아의 세포막을 투과하지 못하기 때문에 지방산은 CoA로부터 카르니틴으로 운반되어 미토콘드리아에서 작용한다. 노화와 연관된 L-carnitine의 기능을 확인하기 위하여 MMP inhibition assay와 자외선 조사에 의해 유도된 MMP 발현에 대한 영향을 확인하였다. MMP inhibition assay는 콜라겐을 이용한 형광분석법을 실시하였고 자외선 조사에 의해 유도된 MMP 발현양은 ELISA로 정량하였으며 그 활성은 젤라틴 기질 zymography로 확인하였고 MMP mRNA 발현양은 RT-PCR ELISA로 확인하였다. 또한, 사람을 이용한 임상 실험을 통하여 주름 개선 효과를 평가하였다. L-carnitine은 농도 의존적으로 MMP 저해 활성을 나타났으며 $IC_{50}$값은 2.45 mM이었으며 자외선 조사에 의해 발현된 MMP 활성을 강하게 저해하였다. 자외선 조사에 의해 발현되는 MMP에 대해 단백질의 양적인 변화는 $40\%$ 정도 감소되었으며 L-carnitine 처리에 의해 농도 의존적으로 MMP mRNA의 발현양은 감소되었다. 이러한 실험결과를 통하여 L-carnitine은 MMP 효소의 저해능 뿐만 아니라 자외선 조사에 의해 유도되는 MMP 단백질 발현과 mRNA 유전자 수준에서의 조절이 가능함을 확인하였다. 사람을 이용한 임상 실험에서는 $1\%$ 카르니틴을 함유하는 화장품을 약 3개월간 사용 후에는 유의적으로 주름 개선 효과를 확인하였다. 결론적으로 L-Carnitine은 광노화에 관여하는 MMP 활성과 발현 조절 메커니즘을 통하여 광손상에 대응하는 항노화 소재로서의 화장품에 매우 효과적이었음을 확인하였다.

• 대한소아치과학회지
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• 제32권3호
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• pp.557-568
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• 2005

전남대학교 치과대학 소아치과학교실 및 치의학 연구소 수복재료로 사용되는 복합레진은 치아의 저작기능과 심미성을 회복할 수 있는 물리적, 화학적 성질뿐만 아니라 생물학적 적합성과 구강내 환경변화에 대한 내구성을 가지고 있어야 한다. 유치에 사용하려고 할 때에도 마모저항성과 구강내 환경에서의 분해저항성은 고려해야할 중요한 물성이다. 실험에 사용된 복합레진은 최근에 시판되고 있는 Metafil CX(Sun Medical, Japan) Solitaire 2(Heraeus Kulzer, USA), Composan LCM(Promedica, Germany), DenFil(Vericom, Korea)이었다. 각 제품의 분해저항성과 마모도를 평가하고자 마모시험 후 마모된 면의 깊이를 측정하였고 화학적분해를 얻기 위해 0.1N NaOH에 보관 시 각 제품의 분해저항성을 무게손실, 표면하 분해층 깊이, 용출된 Si 농도를 기준으로 평가하였고 주사전자현미경과 공촛점 레이저 현미경으로 분해층을 관찰하여 다음과 같은 결과를 얻었다. 1. 무게 손실량은 0.74~7.94%까지 다양하였으며 Metafil에서 가장 높았다. 2. 분해층 깊이는 Metafil이 가장 깊었고 Solitare 2, Denfil, Composan LCM순이었고 Metafil은 다른제품과 유의한 차이를 보였다(p<0.05). 3. Si 용출량은 Metafil이 가장 많았으며 Metafil CX와 Composan LCM, DenFil, Solitaire 2사이에 유의한 차이를 보였다(p<0.05). 4. 주사전자현미경 관찰시 표면 양상 및 분해층 깊이를 관찰할 수 있었고 공촛점 레이저 현미경 관찰시 NaOH 용액에 보관한 후 수복재의 기질과 충전제 사이의 결합의 파괴 양상을 관찰할 수 있었다. 5. 최대마모깊이는 DenFil에서 가장 낮았고, Metafil CX에서 가장 깊었으며 각 제품 간에는 유의한 차이를 보였다(p<0.05). 6. 각 제품의 Si 용출량과 분해층 깊이 사이(r=0.491, p<0.05), 최대마모깊이와 비커스경도 간(r=-0.942, p<0.01)에 유의한 상관관계를 보였다. 이상의 결과 복합레진의 평가요소로서 마모도와 함께 가수분해도 고려되어야 할 것으로 사료된다.

• 설비공학논문집
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• 제24권6호
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• pp.521-537
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• 2012

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2011. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends of thermal and fluid engineering have been surveyed as groups of fluid machinery and fluid flow, thermodynamic cycle, and new and renewable energy. Various topics were presented in the field of fluid machinery and fluid flow. Research issues mainly focused on the rankine cycle in the field of thermodynamic cycle. In the new and renewable energy area, researches were presented on geothermal energy, fuel cell, biogas, reformer, solar water heating system, and metane hydration. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer, nanofluids and industrial heat exchangers. Researches on heat transfer characteristics included heat transfer above liquid helium surface in a cryostat, methane hydrate formation, heat and mass transfer in a liquid desiccant dehumidifier, thermoelectric air-cooling system, heat transfer in multiple slot impinging jet, and heat transfer enhancement by protrusion-in-dimples. In the area of pool boiling and condensing heat transfer, researches on pool boiling of water in low-fin and turbo-B surfaces, pool boiling of R245a, convective boiling two-phase flow in trapezoidal microchannels, condensing of FC-72 on pin-finned surfaces, and natural circulation vertical evaporator were actively performed. In the area of nanofluids, thermal characteristics of heat pipes using water-based MWCNT nanofluids and the thermal conductivity and viscosity were measured. In the area of industrial heat exchangers, researches on fin-tube heat exchangers for waste gas heat recovery and Chevron type plate heat exchanger were implemented. (3) Refrigeration systems with alternative refrigerants such as $CO_2$, hydrocarbons, and mixed refrigerants were studied. Heating performance improvement of heat pump systems were tried applying supplementary components such as a refrigerant heater or a solar collector. The effects of frost growth were studied on the operation characteristic of refrigeration systems and the energy performance of various defrost methods were evaluated. The current situation of the domestic cold storage facilities was analyzed and the future demand was predicted. (4) In building mechanical system fields, a variety of studies were conducted to achieve effective consumption of heat and maximize efficiency of heat in buildings. Various researches were performed to maximize performance of mechanical devices and optimize the operation of HVAC systems. (5) In the fields of architectural environment and energy, diverse purposes of studies were conducted such as indoor environment, building energy, and renewable energy. In particular, renewable energy and building energy-related researches have mainly been studied as reflecting the global interests. In addition, various researches have been performed for reducing cooling load in a building using spot exhaust air, natural ventilation and energy efficiency systems.

• 설비공학논문집
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• 제25권6호
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• pp.346-361
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• 2013

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2012. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. The conclusions are as follows : (1) The research works on thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and valves, fuel cells and power plants, ground-coupled heat pumps, and general heat and mass transfer systems. Research issues are mainly focused on new and renewable energy systems, such as fuel cells, ocean thermal energy conversion power plants, and ground-coupled heat pump systems. (2) Research works on the heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer, and industrial heat exchangers. Researches on heat transfer characteristics included the results for natural convection in a square enclosure with two hot circular cylinders, non-uniform grooved tube considering tube expansion, single-tube annular baffle system, broadcasting LED light with ion wind generator, mechanical property and microstructure of SA213 P92 boiler pipe steel, and flat plate using multiple tripping wires. In the area of pool boiling and condensing heat transfer, researches on the design of a micro-channel heat exchanger for a heat pump, numerical simulation of a heat pump evaporator considering the pressure drop in the distributor and capillary tubes, critical heat flux on a thermoexcel-E enhanced surface, and the performance of a fin-and-tube condenser with non-uniform air distribution and different tube types were actively carried out. In the area of industrial heat exchangers, researches on a plate heat exchanger type dehumidifier, fin-tube heat exchanger, an electric circuit transient analogy model in a vertical closed loop ground heat exchanger, heat transfer characteristics of a double skin window for plant factory, a regenerative heat exchanger depending on its porous structure, and various types of plate heat exchangers were performed. (3) In the field of refrigeration, various studies were executed to improve refrigeration system performance, and to evaluate the applicability of alternative refrigerants and new components. Various topics were presented in the area of refrigeration cycle. Research issues mainly focused on the enhancement of the system performance. In the alternative refrigerant area, studies on CO2, R32/R152a mixture, and R1234yf were performed. Studies on the design and performance analysis of various compressors and evaporator were executed. (4) In building mechanical system research fields, twenty-nine studies were conducted to achieve effective design of mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, renewable energy systems, and lighting systems in buildings. New designs and performance tests using numerical methods and experiments provide useful information and key data, which can improve the energy efficiency of buildings. (5) In the fields of the architectural environment, studies for various purposes, such as indoor environment, building energy, and renewable energy were performed. In particular, building energy-related researches and renewable energy systems have been mainly studied, reflecting interests in global climate change, and efforts to reduce building energy consumption by government and architectural specialists. In addition, many researches have been conducted regarding indoor environments.