• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.125-130
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• 2008

The main components of the KSTAR helium refrigeration system (HRS) can be classified into the warm compression system (WCS) and the cryogenic devices according to the operating temperature levels. The WCS itself consists of the compressor station (C/S) and the oil removal system (ORS). The process helium is compressed from 1 bar to 22 bar maximum in the C/S and downstream, the ORS removes the oil mixed in the helium to less than 10 ppbw as per the operation criteria of the cryogenic devices of the KSTAR HRS. After the installation, the pre-commissioning and commissioning activities were started on July, 2007. Before the start-up of the C/S, vibration measurement and the skid reinforcement jobs were performed for stable operation of the C/S. The results of the WCS performance tests met the requirements of the KSTAR HRS but satisfied the vibration level criteria only at the compressors' full load condition.

• 한국태양에너지학회 논문집
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• 제29권1호
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• pp.18-23
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• 2009

We intend to describe a 12kW building-integrated photovoltaic system which was applied into the south wall of a new building. This study showed the results that were appeared from describing the PV module manufacture and installation process, and performing generation performance analysis of BIPV system. From the result we confirmed that the generation performance of the BIPV system was changed by season. The performance ratio(PR) was about 83.6% in winter and it means that performance of this BIPV system was so good in that season. On the other hand, the PR in summer was about 75.0% dropped about 8%. It was believed that the change was influenced by the reduction of solar radiation irradiated into the PV modules by installation position and rainy spell in summer. And we also confirmed that low irradiation condition is cause of the additional loss in the total PV system. In this case, the efficiency ratio of PCS drops significantly at low input loads and the average conversion efficiency of PCS in summer was 76.4% decreased about 10% from 86% in winter.

• 한국가스학회지
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• 제24권1호
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• pp.33-40
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• 2020

해양플랜트용 HVAC(Heating Ventilation and Air-Conditioning) 시스템의 컨덴싱 유닛(condensing unit)의 경우, DX(Direct Expansion) 코일보다는 온도 안정성이 뛰어난 칠러 시스템(chiller system)을 주로 사용하고 있다. 칠러시스템의 구성품 중 대형 냉매압축기와 전자식 팽창밸브 등은 대부분 수입되고 있다. 이에 칠러 시스템의 크기는 국내에서 제작되는 열교환기(증발기, 응축기)에 의해 좌우된다. 현재 갈수록 심화되고 있는 사용공간의 제한으로 인해 선주사 및 조선소에서는 장비 크기를 컴팩트하게 해줄 것을 메이커에 지속적으로 요구하고 있다. 이에 본 논문에서는 해양플랜트에서 만액식(flooded) 칠러 시스템의 증발기로 주로 사용되고 있는 쉘-튜브형 열교환기를 컴팩트한 플레이트-쉘 열교환기로 대체하기 위한 주요개발과정을 소개하고, 이와 함께 개발된 플레이트-쉘 열교환기를 실제 증발기로 적용한 만액식 칠러 시스템을 제작하여 그 성능을 실험적으로 평가하였으며 그 결과를 제공하고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.362-365
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• 2005

Currently Chemical Mechanical Planarization (CMP) has become an essential step in the overall semiconductor wafer fabrication technology. Especially the CMP pad conditioner, one of the diamond tools, is required to have strong diamond retention. Strong cohesion between diamond grits and metal matrix prevents macro scratch on the wafer. If diamond retention is weak, the diamond will be pulled out of metal matrix. The pulled diamond grits are causative of macro scratch on wafer during CMP process. Firstly, some results will be reported of cohesion between diamond grits and metal matrix on the diamond tools prepared by three different manufacturing methods. A measuring instrument with sharp cemented carbide connected with a push-pull gauge was manufactured to measure the cohesion between diamond grits and metal matrix. The retention force of brazed diamond tool was stronger than the others. The retention force was also increased in proportion to the contact area of diamond grits and metal matrix. The brazed diamond tool has a strong chemical combination of the interlayer composed of chrome in metal matrix and carbon which enhance the interfacial cohesion strength between diamond grits and metal matrix. Secondly, we measured real-time data of the coefficient of friction and the pad wear rate by using CMP tester (CETR, CP-4). CMP pad conditioner samples were manufactured by brazed, electro-plated and sintered methods. The coefficient of friction and the pad wear rate were shown differently according to the arranged diamond patterns. Consequently, the coefficient of friction is increased according as the space between diamonds is increased or the concentration of diamonds is decreased. The pad wear rate is increased according as the degree of diamond protrusion is increased.

• 한국가스학회지
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• 제7권4호
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• pp.36-43
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• 2003

본 논문에서는 LNG 냉열 에너지를 활용한 지역 냉방 시스템 가능성에 대해 고찰하고자 한다. 액상의 LNG는 기상의 가스로 변환하는 과정에서 많은 냉열 에너지를 발생한다. 최근에 빙축열을 이용한 건물의 냉방 시스템 구축과 심층수를 이용한 지역 냉방 시스템이 도심지의 기존 사무실 건물이나 대규모 건물의 냉방장치로 도입되고 있는 상황이다. LNG의 냉열 에너지는 기존의 냉매에 의존한 개별 냉방 시스템을 대체하는 새로운 냉열 에너지 공정으로 쾌적한 공간을 제공하는 천연의 대규모 냉각매체로 재사용될 수 있다. 버려지는 냉열 에너지는 낮은 코스트로 운영될 수 있는 중요한 청정 에너지원이기 때문에 냉방 시스템으로 개발되면, 기존의 에어콘 시스템에 견주어 볼 때 공기중에 유해한 오염원의 발생과 환경적으로 유해한 냉매 방출을 대폭적으로 줄일 수 있는 우수한 냉방 시스템이 될 것이다. 따라서, 본 연구에서는 냉열 에너지를 활용한 지역 냉방 시스템에 대한 환경 친화적 기본적 설계 개념, 여러 가지 냉방 시스템 성능에 대한 유익한 기반적 정보를 제공하고자 한다.

• 한국건설순환자원학회논문집
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• 제9권3호
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• pp.375-382
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• 2021

자기치유 콘크리트는 직접적인 보수보강 없이도 스스로 구조물의 균열을 치유하여 효율적으로 콘크리트 구조물의 수명연장이 가능하다는 측면에서 각광받고 있다. 현재 자기치유 콘크리트는 전 세계적으로 활발히 연구가 진행되고 있는 분야이지만 대부분의 연구는 치유 성능의 향상에 초점을 맞추고 있기 때문에 객관적으로 치유성능을 평가하는 방법은 부족한 실정이다. 자기치유 콘크리트의 성능평가에 활용하기 위해 기체확산실험 방법이 개발된 바가 있지만, 시편의 포화도 및 실험시의 온습도 등과 같은 환경조건의 통제가 필요하다는 단점이 있다. 따라서 본 연구에서는 기체 확산 실험시에 필요한 환경조건을 대폭 완화하여 적용성을 향상시키고자 하였다. 아울러 실험시간을 단축시키고자 사전 안정화 과정을 도입하였고, 약 20분이내의 실험시간에서 3%이내의 오차 수준으로 균열폭의 추정이 가능하였다.

• 방사성폐기물학회지
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• 제4권1호
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• pp.77-85
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• 2006

한국원자력연구소에서는 현재 사용후핵연료의 효율적인 관리를 위한 차세대관리 종합공정의 실증용 핫셀을 건설중에 있다. 이 핫셀에서 모든 물품의 반출입은 후면 차폐문을 통해 이루어지므로 차폐문의 사용빈도가 매우 크며, 따라서 후면 차폐문의 구조적 안전성 유지가 필수적이다. 본 논문에서는 핫셀의 후면 차폐문에 대한 구조적 안전성을 유한요소 해석을 통해 평가하였다. 후면 차폐문을 닫을 때 벽면의 차폐문틀과 충돌하면서 발생하는 구조적 변형 에 대한 안전성 평가를 위해 이 상황을 충돌-접촉 문제로 가정하고 동적 해석을 수행하였다. 또한 충돌시 반력에의한 후면 차폐문의 전도 가능성 및 이동중 갑작스럽게 정지할 경우 관성에 의한 전도 가능성에 대해서도 해석을 수행하였다. 해석 결과를 통해 차폐문과 차폐문틀 모두 충돌에 의한 구조적 변형에 대해 충분히 안전함을 확인할 수 있었으며, 여러 사고 조건에 대해서도 후면 차폐문의 전도가 일어나지 않고 안정성을 유지함을 보였다.

• 대한예방한의학회지
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• 제10권1호
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• pp.109-121
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• 2006

The purpose of this study was to determine factors influencing patient satisfaction with medical services in hospital, which is classified into environmental aspect, human services and procedural services. Based on the results of literature review, the study focused on effects of social-demographical factors on patient satisfaction. The environmental aspect of medical care services included medical equipment and facilities, hygiene, ventilation, heating and air-conditioning, waiting and resting space, ward space and parking facilities. Procedural service included registration process, bill payment, waiting time after registration, examination and prescription as well as appointment process. Human services consisted of physicians listening to stories of patients, examination duration, physicians' explanation and physicians' service. As for nurses, explanation about disease, examination procedure and results, kindness and nursing care were evaluated. Services provided by other staff members were also evaluated. Patient satisfaction, defined as individual attitude toward medical service as a whole, was measured using a questionnaire. A total of 700 in-or out-patients were surveyed in 6 hospitals with more than 300 beds in North Gyeongbuk Province. 1. The level of patient satisfaction varied with characteristics of patients. Male patients and those in their 30s had a low level of satisfaction. Dissatisfaction level was positively related to education level but negatively related to economic condition. 2. As for patient satisfaction with medical service providers and other employees in hospital, satisfaction level with physician's explanation about treatment was higher. But dissatisfaction levels with treatment duration and the lack of explanation about examination procedures were high, calling for improvement. Dissatisfaction level with nursing care was high, calling for training of nurses for better service. Given the low level of satisfaction with human services, hospital employees need to be trained to improve their service. 3. It Was found that administrative service was also a significant factor influencing patient satisfaction in addition to medical service. It is therefore important for hospitals to provide patients with prompt and convenient procedural service. 4. Environmental factors such as medical equipment and amenity facilities also affected patient satisfaction. Thus environmental condition, procedural service and human service are all important to improve medical service in hospital. In summary, procedural service was the most significant factor for patient satisfaction. The level of satisfaction in patients was also affected by human service and environmental condition. It is therefore necessary to take patient-oriented approach in providing medical service in an effort to improve patient satisfaction. The finding of a lower level of satisfaction with human service signifies the need for training of healthcare providers and other hospital employees for better services. The introduction of advanced management programs is also needed to improve procedures that patients go through in hospitals.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.170-174
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• 2008

Recently, a problem related to the thermal management in portable electronic and telecommunication devices is becoming issued. That is due to the trend of slimness of the devices, so it is not easy to find the optimal thermal management technology for the devices. From now on, a pressed circular type cooling device has been mainly used, however the cooling device with thin thickness is becoming needed by the inner space constraint. In the present study, the silicon and metal flat plate type cooling device with the separated vapor and liquid flow path was designed and fabricated. Through the experimental study, the normal isothermal characteristic by vapor-liquid phase change was confirmed and the cooling device with 70mm of total length showed 6.8W of the heat transfer rate within the range of $4{\sim}5^{\circ}C$/W of thermal resistance. In the meantime, the metal cooling device was developed for commercialization. The device was designed to have all structures of evaporator, vapor flow path, liquid flow path and condenser in one plate. And an envelope of that could be completed by combining the two plates of same structure and size. And the simplicity of fabrication process and reduction of manufacturing cost could be accomplished by using the stamping technology for fabricating large flow paths relatively. In the future, it will be possible to develop the commercialized cooling device by revising the fabrication process and enhancing the thermal performance of that.

• 헤리티지:역사와 과학
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• 제56권2호
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• pp.124-133
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• 2023

국방부 유해발굴단을 통해 발굴된 한국전쟁 전사자 유품의 보존 방법론을 제시하고자 3D 기술의 적용과 가역성 및 안정성이 우수한 보존 재료를 이용해 군화류 2점에 대한 보존처리를 진행하였다. 3D 스캐닝과 모델링을 통해 군화를 신었던 전사자의 발 사이즈를 추정해 볼 수 있었으며, 이를 기반으로 3D 출력 구조체를 이용해 원형을 복원하였다. 원형 복원은 출토 유품의 오염물 제거와 유연제 처리 작업을 거쳐 구조체의 형태로 복원하였으며, 열화되어 찢겨지거나 멸실된 부분은 접합 및 메움처리 후 고색처리를 통해 원형을 복원하였다. 보존처리 후 2종의 군화 모두 밑창과 발등 부분은 고무류, 발등 일부와 발목 부분은 합성가죽류로 제작된 것을 확인할 수 있었으며, 이는 방수 또는 방한의 목적으로 제작되어 1944년에 도입된 모델 Shoe Pac(M-1944, 12-inch) 방한화와 유사한 군화임을 확인하였다. 이러한 결과는 보존처리를 통해 출토된 유품의 제작기법과 재질, 용도 등을 밝혀낼 수 있음을 확인한 연구로서 과학적 보존처리와 3D 기술의 융합적 연구의 중요성을 보여준 사례이다.