• 설비공학논문집
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• 제28권11호
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• pp.458-465
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• 2016

The purpose of this research is to improve the thermal effiency of solar collector and to quantitatively analyze its performance. Solar thermal systems have been limited to water heating systems mainly using low-temperature range. However, through diverse developments, the application has been extended to medium- and high-temperature fields such as solar heating, solar air conditioning, and solar thermal industrial process. Among the diverse research, this research is specially focusing on enhancement of the thermal performance by minimizing the heat loss coefficient of flat plate solar collectors. In order to do it, a front-side glazing material and a back-side insulation material with high insulated structure is proposed and based on computational analysis, the performance of energy collecting volume of the proposed solar collector is analyzed. The research shows that the proposed structure has the excellent performance at medium- and high-temperature range. therefore, it is expected that the proposed structure can easily replace existing technologies.

• 한국태양에너지학회 논문집
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• 제36권2호
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• pp.65-72
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• 2016

PV module is installed in various outdoor conditions such as solar irradiation, ambient temperature, wind speed and etc. Increase in solar cell temperature within PV module aggravates the behaviour and durability of PV module. It is difficult to measure temperature among respective PV module components during PV module operating, because the temperature within PV module depends on thermal characteristics of PV module components materials as well as operating conditions such as irradiation, outdoor temperature, wind etc. In this paper, simulation by using finite element method is conducted to predict the temperature of each components within PV module installed to outdoor circumstance. PV module structure based on conventional crystalline Si module is designed and the measured values of thickness and thermal parameters of component materials are used. The validation of simulation model is confirmed by comparing the calculated results with the measured temperatures data of PV module. The simulation model is also applied to estimate the thermal radiation of PV module by front glass and back sheet.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.267-273
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• 2012

Solar reforming of methane with CO2 was successfully tested with a direct irradiated absorber on a parabolic dish capable of 5kWth solar power. And the new type of double-layer absorber-the front layer, porous metal foam which absorbs the radiation and transfers the heat from material to gas, and the back layer, catalytically-activated metal foam-was prepared, and its activity was tested by using electric furnace. Ni was applied as the active metal on the gamma-Al2O3 coated Ni metal foam for the preparation of the catalytically-activated metal foam layer. Compared to conventional direct irradiation of the catalytically activated metal foam absorber, this new type of double layer absorber is found to exhibit a superior reaction and thermal storage performance at the fluctuating incident solar radiation. In addition, unlike direct irradiation of the foam absorber, double layer absorber has better thermal resistance, which prevents the emergence of cracks caused by mechanical or thermal shock. The total solar power absorbed reached up to 3.25kW and the maximum CH4 conversion was almost 59%.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.80-86
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• 2011

Solar reforming of methane with CO2 was successfully tested with a direct irradiated absorber on a parabolic dish capable of 5kWth solar power. And the new type of double-layer absorber - the front layer, porous metal foam which absorbs the radiation and transfers the heat from material to gas, and the back layer, catalytically-activated metal foam - was prepared, and its activity was tested by using electric furnace. Ni was applied as the active metal on the gamma-Al2O3 coated Ni metal foam for the preparation of the catalytically-activated metal foam layer. Compared to conventional direct irradiation of the catalytically activated metal foam absorber, this new type of double layer absorber is found to exhibit a superior reaction and thermal storage performance at the fluctuating incident solar radiation. In addition, unlike direct irradiation of the foam absorber, double layer absorber has better thermal resistance, which prevents the emergence of cracks caused by mechanical or thermal shock. The total solar power absorbed reached up to 3.25kW and the maximum CH4 conversion was almost 59%.

• 한국항공우주학회지
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• 제39권2호
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• pp.106-113
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• 2011

본 논문에서는 균일 열부가 하중을 받는 사각판의 자유 진동특성을 실험을 통하여 연구하였다. 사각판의 재질은 알루미늄, 강재 및 스테인레스 강이고 사각판의 재원은 0.1 $\times$ 0.1 $\times$ 0.002 m 이다. 열부가 하중을 위해 적외선 석영 램프를 사용하였고, 전력조절을 위해 PCS(Power Control System)을 사용하였으며, 주파수 함수를 얻기 위해 비접촉식 진동측정 장비를 사용하였다. 부가한 온도 조건은 상온에서부터 $300^{\circ}C$까지 $50^{\circ}C$간격으로 부가하였다. 경계조건은 번지코드를 사용하여 자유-자유 조건을 구현하였다. 사각판의 전면 전체를 균일하게 가열하였다.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2621-2627
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• 2023

In Experimental Advanced Superconducting Tokamak (EAST) experiments, to achieve long pulse and high-power ICRH system operation, a new kind of ICRH antenna has been designed. One of the most critical factors in limiting the operation of long pulse and high power is the intense heat load in the front face of the ICRH antenna, especially the Faraday Screen (FS). Therefore, the cooling channels of FS need to be designed. According to thermal-hydraulic analysis, the FS tubes are divided into several groups to achieve more excellent water cooling capability. The number of series and parallel tubes in one group is chosen as six. This antenna went into service in the spring of 2021, and it is delightful that the temperature distribution of the FS tube is below 400 ℃ in 14.5 s and 1.8 MW ICRH system operation. However, the active water-cooling design was not carried out on the upper and lower plates of FS, which led to severe ablations on that region under long pulse and high power operation, and the temperature is up to 800. Therefore, the upper and lower side plates of the FS were designed with water cooling based on thermal-hydraulic analysis. During the 2022 winter experiments, the temperature of ICRH antenna FS was lower than 400 in the pulse of 200s and the power of 1 MW operation.

• 한국방사선학회논문지
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• 제11권4호
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• pp.273-278
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• 2017

적외선 체열검사를 시행한 $L_4-L_5$ 추간판 탈출증 환자의 45명 중 여자가 더 많았으며, 연령은 50대가 가장 많았다. 피절 분포표에 따라 측정한 결과, ${\chi}^2-test$에서는 성별과 나이에 따라서 유의한 차이를 보이지 않았다(p>0.05). $L_4-L_5$ 추간판 탈출증 환자의 ROI 온도를 측정한 부위는 후면 오른쪽 정강이뼈 뒤쪽의 온도가 가장 높았으며, 후면 왼쪽 정강이뼈 뒤쪽-전면 오른 무릎아래-전면 왼 무릎아래의 순이었다. 측정부위에 따라 유의한 차이를 보였다(p<0.05). 나이에 따라서는 ${\chi}^2-test$에서는 나이에 따라 0.030을 유의한 결과를 보였다(p<0.05). 정상인의 평균 ROI 온도는 $31.20{\pm}0.58$, 환자의 평균 ROI온도는 $30.30{\pm}0.50$으로 온도 차이는 $0.66{\pm}0.59$로 나타났다. 환자의 ROI온도가 정상인과 차이가 나는 지 알아보기 위한 일 표본 t-검정결과, 유의확률이 0.03으로 0.05보다 작으므로 환자의 ROI온도는 $31.20{\pm}0.58$보다 낮게 나타났다(p<0.05). 앞으로의 과제는 온열환경에 따른 보정 테이타의 처리기술과 그것을 이용한 새로운 온열 인덱스의 개발이 필요하다고 사료된다. 따라서 데이타의 보정을 줄이기 위해서는 적외선 체열 진단 시 전처치가 무엇보다 중요하며, 이를 검사하는 방사선사는 환자를 측정 시 주의 깊은 관찰과 배려가 요구된다.

• 한국자동차공학회논문집
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• 제17권2호
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• pp.10-19
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• 2009

The working of diesel particulate filters(DPF) needs to periodically burn soot that has been accumulated during loading of the DPF. The prediction of the relation between an uniformity of gas velocity and soot regeneration efficiency with simulations helps to make design decisions and to shorten the development process. This work presents a comprehensive combined 'DOC+CDPF' model approach. All relevant behaviors of flow fluid are studied in a 3D model. The obtained flow fields in the front of DPF is used for 1D simulation for the prediction of the thermal behavior and regeneration efficiency of CDPF. Validation of the present simulation are performed for the axial and radial direction temperature profile and shows goods agreement with experimental data. The coupled simulation of 3D and 1D shows their impact on the overall regeneration efficiency. It is found that the flow non-uniformity may cause severe radial temperature gradient, resulting in degrading regeneration efficiency.

• 한국자동차공학회논문집
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• 제6권3호
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• pp.1-10
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• 1998

In this paper, we investigated the improvement of characteristics of knock, emission and fuel consumption rate by optimizing the location and size of water transfer holes in cylinder head gasket without change of engine water jacket design itself. The cooling system was modified in the direction of reducing the metal temperature in the head and increasing the metal temperature in the block. The optimization of water transfer holes in cylinder head gasket was obtained by "flow visualization test". The water transfer holes were concentrated in front side of the engine in order to reduce thermal boundary layer in the water jacket of No. 2 and No. 3 combustion changer in the cylinder head, which would have a large knock intensity, and increase thermal boundary layer in the water jacket of the cylinder block. When the modified coolant flow pattern was applied as proposed in this paper, the knock characteristic was improved. The spark timing was advanced up to 2$^{\circ}$ in low and middle speed range at a full load. In addition, HC emission at MBT was reduced by 5.2%, and the fuel consumption rate was decreased up to 1% in the driving condition of 2400 rpm and 250 KPa. However, since this coolant flow pattern mentioned in this paper might deteriorate the performance of vehicle cooling system due to the coolant flow rate reduction, a properly optimized point should be obtained. obtained.

• 대한인간공학회지
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• 제15권2호
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• pp.71-88
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• 1996

For understanding skin temperature based on clothing design from a viewpoint of comfortable wearing, the skin temperature, physiological reactions(body temperature, blood pressure and pulse) and physilolgical response(thermal sensation, comfort sensation and perceptive sweaty sensation) were measured on condition tha t5 naked healthy male exposed to serveral environmental temperatures,( $20{\pm}1.0^{\circ}C$ ,$28{\pm}1.0^{\circ}C$ and $32{\pm}1.0^{\circ}C$). As the results of this testing, the regional skin temperature was varied for 90min just after expose to those the environment but was generally stabilized for the nest 90min. It was proved the difference of the regional skin temperature at low temperature environmental($20{\pm}1.0^{\circ}C$) was larger than at high temperature environmental($32{\pm}1.0^{\circ}C$) and inder serveral environmental temperature,the degree of the regional skin was not equal. Except in case of the thigh, the front of all regional skin temperature turned out higher than the back of them. According to change of environmental temperature, body temperature and pulse were altered. In the pshycological response, 'thermal sensation-comfort sensation' was felt to 'slightly warm - comfortable' at $28{\pm}1.0^{\circ}C$of the environmental temperature, and 'perceptive sweaty sensation', wneh it was said 'sweat' at only $32{\pm}1.0^{\circ}C$ of it.