• 해양환경안전학회지
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• 제19권2호
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• pp.207-212
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• 2013

본 연구에서는 선박의 중앙집중 공조시스템에 공랭식 에어컨을 직접 설치하여 열원의 성능개선과 거주 구역별 독립 냉 난방이 가능한 개별분산 공조시스템을 하고자 하는 것이다. 연구 결과 기존의 중앙집중방식 공조시스템에 비해 열원 제어와 열효율상의 문제점을 보완함과 동시에 장치의 효율을 향상시킴을 확인하였다. 또한 동일한 조건에서 장치의 냉동능력과 성능계수는 평균 약 3 %, 23~26 % 정도 높게 나타났으며, Chilled Water Plants의 압축기 소비동력은 약 12 % 정도 낮게 나타났고, 동일한 조건에서 난방 시 소비동력은 약 33.5 % 낮게 나타났다. 따라서 공랭식 에어컨을 이용한 개별분산 공조시스템이 열원 제어뿐만 아니라 장치의 성능향상과 거주구역별 쾌적한 온 습도 환경 조성에 크게 기여하는 결과를 얻을 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.86.2-86.2
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• 2010

In order to improve polymer electrolyte membrane fuel cell (PEMFC) durability, the durability of membrane electrode assemblies (MEA), in which the electrochemical reactions actually occur, is one of the vital issues. Many articles have dealt with catalyst layer degradation of the durability-related factors on MEAs in relation to loss of catalyst surface area caused by agglomeration, dissolution, migration, formation of metal complexes and oxides, and/or instability of the carbon support. Degradation of catalyst layer during long-term operation includes cracking or delamination of the layer which result either from change in the catalyst microstructure or loss of electronic or ionic contact with the active surface, can result in apparent activity loss in the catalyst layer. Membrane degradation of the durability-related factors on MEAs can be caused by mechanical or thermal stress resulting in formation of pinholes and tears and/or by chemical attack of hydrogen peroxide radicals formed during the electrochemical reactions. All of these effects, the mechanical damage of membrane and degradation of catalyst layers are more facilitated by uneven stress or improper MEA fabrication process. In order to improve the PEMFC durability, therefore, it is most important to minimize the uneven stress or improper MEA fabrication process in the course of the fabrication of MEA. We analyzed the effects of the MEA fabrication condition on the PEMFC durability with MEA produced using CCM (catalyst coated membrane) method. This paper also investigated the effects of MEA fabrication condition on the PEMFC durability by adding additional treatment process, hot pressing and pressing, on the MEA produced using CCM method.

• 한국재료학회지
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• 제24권11호
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• pp.573-577
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• 2014

The existing metal getters are invariably covered with thin oxide layers in air and the native oxide layer must be dissolved into the getter materials for activation. However, high temperature is needed for the activation, which leads to unavoidable deleterious effects on the devices. Therefore, to improve the device efficiency and gas-adsorption properties of the device, it is essential to synthesize the getter with a method that does not require a thermal activation temperature. In this study, getter material was synthesized using palladium oxide (PdOx) which can adsorb $H_2$ gas. To enhance the efficiency of the hydrogen and moisture absorption, a porous layer with a large specific area was fabricated by an etching process and used as supporting substrates. It was confirmed that the moisture-absorption performance of the $SiO_2/Si$ was characterized by water vapor volume with relative humidity. The gas-adsorption properties occurred in the absence of the activation process.

• 한국표면공학회지
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• 제37권2호
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• pp.71-75
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• 2004

The technology of $C_{60}$ fullerite films preparation by means of gas-phase deposition and structure of fullerite films are described. A three-channel flow plant was used to obtain fullerite films. The films were deposited in the flow of inert gas under reduced pressure onto a cooled silicon or sapphire substrate placed inside the reaction chamber of the plant. The plant allows one to obtain the films of pure fullerenes and to synthesise the films from fullerene compounds and doped fullerenes. The structure of two types of films were investigated by FE-SEM and SEM techniques: pure fullerite films onto silicon and sapphire substrates as well as compound films were studied by FE-SEM technique. All samples have shown columnar structure with high level of porosity. The synthesis of films composed of fullerene and its compounds for use in electronics is demonstrated to be promising. For example, experiments confirm the possibility to use fullerite films in sensor electronics to produce humidity and thermal sensors. It is also possible to use the sensitivity of these films to isotropic pressure. The experiments with $C_{60}$-Cu-J films have shown quite strong dependence of their resistance on pressure of different sort of medium-gas that could be used in gas-sensitive sensors. The structure and preparation technology of resistive sensor based on fullerite films are described.bed.

• 한국항해항만학회지
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• 제35권3호
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• pp.265-270
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• 2011

본 연구는 건물에너지 효율 향상을 위한 목적으로 기상데이터 변화에 따른 건물 냉 난방부하량을 예측하고 결과를 비교 분석한 것으로, 연구 성과는 다음과 같다. 1)기상청에서 입수데이터를 평가툴인 ESP-r에 활용할 수 있도록 항목별 기상데이터를 개발하였다. 표준기상 데이터의 외기온도, 습도, 풍속은 대부분의 경우 기상청데이터 보다 크거나 높았다. 수평면전일사량은 기상청데이터가 높았고, 직달일사량은 겨울철에는 표준기상데이터가, 여름철에는 기상청데이터가 많은 것으로 나타났다. 2)대학교 캠퍼스 내에 신축된 후생복지관을 대상으로 한 시뮬레이션 결과, 최대난방부하의 경우 표준년도, 2006년, 2009년이 비슷한 반면 2007년은 표준년도 대비 81%, 2008년은 96% 수준이었고, 연간난방부하는 2006년, 2008년의 순으로 난방수요가 많았다. 한편, 냉방부하의 경우에는, 상대적으로 최대냉방부하가 큰 2007년, 2009년의 연간 냉방부하보다 최대냉방부하가 가장 적은 2008년의 연간냉방부하가 더 큰 결과를 보였다. 3)냉 난방기기의 상당시간가동률을 평가한 결과, 표준년도의 최대부하대비 상당시간가동률은 2006~2009년이 표준년도에 비해 대부분 가동률이 낮았다.

• International Journal of Industrial Entomology and Biomaterials
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• 제25권2호
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• pp.159-162
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• 2012

The Chinese windmill butterfly, Atrophaneura alcinous, is an important butterfly for exhibition in butterfly garden. The objective of this study was to determine the effect of temperature on A. alcinous in the laboratory. Development of A. alcinous reared on leaves of Aristolochia contorta was investigated at five constant the laboratory condition (20, 22.5, 25, 27.5 and $30^{\circ}C$) and at relative humidity of 60% with a photoperiod of 14:10 (L:D). Temperatures have been suggested as an important determinant of developmental rate, lifespan and mortality in invertebrates. As the temperature increased, the length of the developmental period gradually decreased. The developmental time (pupation) from egg hatching to pupation was respectively 25.8, 23.6, 19.6, 15.5, and 12.9 days at the temperatures of 20, 22.5, 25, 27.5 and $30^{\circ}C$. And pupation was respectively 40.0, 30.0, 63.4, 50.0, 23.3% at the temperatures of 20, 22.5, 25, 27.5 and $30^{\circ}C$. The developmental threshold temperature estimated for egg-to-pupae was 10.8, with a thermal constant of 230.4 degree-days. Therefore, the optimal developmental temperature for A. alninous was determined to be $25^{\circ}C$. To compare the effects of the total duration of chilling on the termination of diapause, larvae were subjected to a temperature of $8^{\circ}C$ from 60 to 120 days. The rate of termination of diapause was significantly higher at 60 days compared to other incubation period.

• Computers and Concrete
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• 제18권5호
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• pp.1041-1051
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• 2016

In this study, the construction of a reinforced concrete bridge pier was analyzed from durability point of view. The goal of the study is to analyze the crack iniation condition due to construction and present some recommendations for construction conditions of the reinforced concrete bridge pier. The bridge is located at the western port area of Shenzhen, where the climate is high temperature and humidity. To control the cracking of concrete, a construction simulation was carried out for a heat transfer problem as well as a thermal stress problem. A shrinkage model for heat produced due to cement hydration and a Burger constitutive model to simulate the creep effect are used. The modelling based on Femmasse(C) is verified by comparing with the testing results of a real underground abutment. For the bridge pier, the temperature and stress distribution, as well as their evolution with time are shown. To simulate the construction condition, four initial concrete temperatures ($5^{\circ}C$, $10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$) and three demoulding time tips (48h, 72h, 96h) are investigated. From the results, it is concluded that a high initial concrete temperature could result in a high extreme internal temperature, which causes the early peak temperature and the larger principle stresses. The demoulding time seems to be less important for the chosen study cases. Currently used 72 hours in the construction practice may be a reasonable choice.

• Safety and Health at Work
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• 제6권3호
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• pp.256-262
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• 2015

Background: Heart attack is the most common cause of line-of-duty death in the fire service. Daily aspirin therapy is a preventative measure used to reduce the morbidity of heart attacks but may decrease the ability to dissipate heat by reducing skin blood flow. Methods: In this double-blind, placebo-controlled, crossover study, firefighters were randomized to receive 14 days of therapy (81-mg aspirin or placebo) before performing treadmill exercise in thermal-protective clothing in a hot room [$38.8{\pm}2.1^{\circ}C$, $24.9{\pm}9.1%$ relative humidity (RH)]. Three weeks without therapy was provided before crossing to the other arm. Firefighters completed a baseline skin blood-flow assessment via laser Doppler flowmetry; skin was heated to $44^{\circ}C$ to achieve maximal cutaneous vasodilation. Skin blood flow was measured before and after exercise in a hot room, and at 0 minutes, 10 minutes, 20 minutes, and 30 minutes of recovery under temperature conditions ($25.3{\pm}1.2^{\circ}C$, $40.3{\pm}13.7%\;RH$). Platelet clotting time was assessed before drug administration, and before and after exercise. Results: Fifteen firefighters completed the study. Aspirin increased clotting time before and after exercise compared with placebo (p = 0.003). There were no differences in absolute skin blood flow between groups (p = 0.35). Following exercise, cutaneous vascular conductance (CVC) was $85{\pm}42%$ of maximum in the aspirin and $76{\pm}37%$ in the placebo groups. The percentage of maximal CVC did not differ by treatment before or after recovery. Neither maximal core body temperature nor heart rate responses to exercise differed between trials. Conclusion: There were no differences in skin blood flow during uncompensable heat stress following exercise after aspirin or placebo therapy.

• 지구물리와물리탐사
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• 제18권3호
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• pp.105-114
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• 2015

상온 상습 환경에서 수포화 암석코어의 전기비저항을 장시간 모니터링 할 수 있는 장치를 구현하였다. 양쪽 금속망 전극에 덧댄 종이필터와 암석코어를 감싼 열수축튜브의 상부 중앙 외피면에 3-채널 펌프로 물을 충분히 공급하면서 전기저항을 측정하면 암석코어의 수포화 상태를 유지하면서 일주일 이상 전기비저항을 모니터링 할 수 있다. 이 장치를 이용하여 흑운모 편마암, 안산암질 응회암, 셰일의 3종류 암석코어의 수포화 전기저항을 9일간 모니터링 한 결과 다음과 같은 2가지 가설을 제시할 수 있었다. 즉, 전기비저항 온도계수의 수렴 속도는 열물성과 관련이 있을 것이라는 것과 건조 저항을 수포화 때의 평균 저항으로 나눈 건조/수포화 저항비는 유효공극률과 상관될 것이라는 것이다. 실제로, 3가지 암석의 건조/수포화 저항비는 각각 48, 705, 2로 나타났고 이때 각각의 유효공극률은 3.7%, 3.3%, 13.0%이었다.

• 한국환경보건학회지
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• 제43권3호
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• pp.214-222
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• 2017

Objectives: A hospital is a complex building that serves many different purposes. The indoor environment in a hospital plays a major role in patient well-being and the work efficiency of the hospital staff. This study was conducted to evaluate overall comfort in two major hospitals over the course of one year. Methods: Various indoor environmental conditions were measured in two general hospitals for one year (April 2014 to April 2015). Monitoring alternated between the hospitals at one month per respective monitoring session. The indoor air temperature, relative humidity (RH), mean radiant temperature and air velocity were measured in order to calculate the predicted mean vote (PMV). Carbon dioxide concentration, noise level and illumination level were concurrently measured and applied to the overall IEQ acceptance model for the hospitals (IEQh). Results: The IEQh at the two general hospitals was different at five spaces within a building. The IEQh for summer and winter were significantly different. Real-time IEQh demonstrated that indoor comfort was affected by the hospital's operating hours due to operation of the HVAC system. The percentage of indoor comfort in the hospitals was higher using PMV than IEQh. Conclusion: IEQh in the hospitals was different at locations with different purposes. Indoor comfort assessment using IEQh was stricter than with PMV. Additional research is needed in order to optimize the IEQh model.