• 한국태양에너지학회 논문집
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• 제21권4호
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• pp.55-62
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• 2001

A parabolic dish concentrator used in a high temperature application of solar energy tracks the sun's movement by two axis sun tracking system. In such a system, sun tracking performance affects the system efficiency directly. Generally the higher the tracking accuracy is, the better the system performance is. A large number of parabolic dish type concentrators has been developed and implemented in the world. However none of them clearly provided a qualitative method of how the accuracy of the sun tracking system can be evaluated. The work presented here is the evaluation of sun tracking performance of parabolic dish concentrator, which follows the sun's movement by the sensor, using a computer vision system. We install a camera on the parabolic dish concentrator. While the concentrator follows the sun, sun's images are captured continuously. Then the performance of sun tracking system was evaluated by analyzing the variation of the position of the sun in the captured images.

• 한국태양에너지학회 논문집
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• 제27권1호
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• pp.29-38
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• 2007

In order to analyze the performance comparison of dish solar collector with mirror arrays and receiver shapes, the radiative heat flux distribution inside the cavity receiver is numerically investigated. The solar irradiation reflected by dish solar collector is traced using the Monte-Carlo method. Five different dish solar collectors and three different cavity receivers are considered. A parabolic-shaped perfect mirror of which diameter is 1.5 m is considered as a reference dish solar collector and four different arrays of twelve identical parabolic-shaped mirror facets of which diameter are 0.4 m are used. Their reflecting areas, which are $1.5\;m^2$, are the same. Three different cavity receiver shapes are dome, conical, and cylindrical. In addition, the radiative properties of the concentrating surfaces can vary the thermal performance of the cavity receiver so that variation of the surface reflectivity of each mirror is considered. Based on the calculation, the design information of dish solar collector for producing the electric power can be obtained. The results show that the dome type has the best performance in receiver shapes and the 2AND4 INLINE has the best performance in mirror arrays except perfect mirror.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.408-408
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• 2000

A parabolic dish concentrator used in a high temperature application of solar energy tracks the sun's movement by two axis sun tracking system. In such a system, sun tracking performance affects the system efficiency directly. Generally the higher the tracking accuracy is, the better the system performance is. A large number of parabolic dish type concentrators has been developed and implemented in the world. However none of them clearly provided a qualitative method of how the accuracy of the sun tracking system can be evaluated. The work presented here is the evaluation of sun tracking performance of parabolic dish concentrator, which follows the sun's movement by the sensor, using computer vision system. We install a camera on the parabolic dish concentrator. While the concentrator follows the sun, sun's images are captured continuously. Then the performance of sun tracking system was evaluated by analyzing the variation of the position of the sun in the images.

• 한국태양에너지학회 논문집
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• 제29권4호
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• pp.22-27
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• 2009

This study focus on verification of the thermal efficiency of volumetric receiver with 5k Wth Dish-type solar thermal system. Spiral flow path shaped on receiver and working fluid(steam) flow along with this flow path. Porous material for radiation-thermal conversion used in former researches are substituted with the stainless steel wall installed along the spiral flow path. Numerical analysis for the flow path and temperature distributions are carried out. Numerical results are compared with experimental data. Using the numerical model, the heat transfer characteristics of spiral type receiver for dish-type solar thermal systems are known and the thermal performance of the receiver can be estimated.

• 설비공학논문집
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• 제20권1호
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• pp.35-41
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• 2008

The radiative heat loss from a receiver of a dish solar collector is numerically investigated. The dish solar collector considered in this paper consists of a receiver and multi-faceted mirrors. In order to investigate the performance comparison of dish solar collectors, six different mirror arrays and four different receivers are considered. A parabolic- shaped perfect mirror of which diameter is 1.40 m is considered as the reference for the mirror arrays. The other mirror arrays which consist of twelve identical parabolic-shaped mirror facets of which diameter are 0.405 m are suggested for comparison. Their reflecting areas, which are 1.545 $m^{2}$, are the same. Four different receiver shapes are a conical, a dome, a cylindrical, and a unicorn type. The radiative properties of the mirror surfaces and the receiver surfaces may vary the thermal performance of the dish solar collector so that various surface properties are considered. In order to calculate the radiative heat loss in the receiver, two kinds of methods are used. The Net Radiation Method that is based on the radiation heat balance on the surface is used to calculate the radiation heat transfer rate from the inside surface of the receiver to the environment. The Monte-Carlo Method that is the statistical approach is adopted to predict the radiation heat transfer rate from the reflector to the receiver. The collector efficiency is defined as the results of the optical efficiency and the receiver efficiency. Based on the calculation, the unicorn type has the best performance in receiver shapes and the STAR has the best performance in mirror arrays except the perfect mirror.

• KSBB Journal
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• 제7권4호
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• pp.278-283
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• 1992

쥐 간세포를 분리하고 여러가지 물질로 표면이 처리된 용기를 이용하여 배양하였다. 표면처리를 하지 않았을 경우와 collagen으로 처리하였을 경우 간세포는 monolayer형태를 이루며 자랐고, heparin과 hyaluronic acid의 경우에는 multilayer, 그리고 proteoglycan, dermatan sulfate(D. S.), BSA의 경우에는 hemispheroid, 그리고 표면처리를 하지 않은 Primaria는 spheroid형태를 형성하였다. 세포 생존도 면에서는 monolayer가 우수하였고, 간세포의 중요한 대사능이라고 볼 수 있는 암모니아의 제거능이나 albumin생산성 면에서는 hemispheroid 혹은 spheroid가 우수하였다.

• 대한가정학회지
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• 제41권4호
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• pp.35-43
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• 2003

This study was carried out to examine the status of Kimchi preparation, number of side dish and breakfast type of some houses in Yosu, Chonnam area. The survey was conducted from October to November, 2000 using a questionnaire. The results are as follows. The majority of monthly income of household was 1∼2 million won (50.1％). The highest family composition os couple and children with 75.6% and the highest number of family member was 3∼4 with 57.0%. The highest type of housing was an apartment with 67.1% while its ownership was, the highest in self-own with 69.9%. The 65.6% of respondants prepared Kimchi at home and the next was from the parent's home. The numbers of side dishes except Kimchi for each meal were 3∼4(63.2%). The major food of breakfast was boiled rice(86.7%). With decreasing age and family numbers and increasing level of education and income, the percent of boiled rice was lower whereas the percent of bread was higher.

• Journal of electromagnetic engineering and science
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• 제13권4호
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• pp.251-258
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• 2013

A procedure for antenna parameter selections is proposed that considers the relationships between synthetic aperture radar performance and the antenna parameters of a parabola-type reflector antenna with a central flat dish. The effects of a central dish designed for weight reduction on the antenna beam pattern are also quantitatively analyzed using commercially available software based on the physical optics algorithm. The results of the theoretical analysis and simulation predict that a larger size of the central dish results in an increase in the sidelobe level, which is the reason for the increase in two important ambiguities, such as range ambiguity ratio (RAR) and azimuth ambiguity ratio (AAR). The dependence of RAR and AAR on Pulse repetition frequency is also analyzed and discussed.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.113-119
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• 2012

The two-step water splitting thermochemical cycle is composed of the T-R (Thermal Reduction) and W-D (Water Decomposition) steps. The mechanism of this cycle is oxidation-reduction, which produces hydrogen. The reaction temperature necessary for this thermochemical cycle can be achieved by a dish-type solar thermal collector (Inha University, Korea). The purpose of this study is to validate a water splitting device in the field. The device is studied and fabricated by Kodama et al (2010, 2011). The validation results show that the foam device, when loaded with $CeO_2$ powder, was successfully achieved hydrogen production under field conditions. Through this experiment, we can analyze the characteristics of the catalyst and able to determine which is more advantageous thing to produce hydrogen compared with previous experiment that used ferrite-device.

• 대한기계학회논문집A
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• 제35권10호
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• pp.1315-1321
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• 2011

제품 생산과 실험에 앞서 설계 단계에서의 강도 평가가 이루어져야 하며, 이 단계에서 범용 프로그램인 ANSYS 의 도입 및 활용은 제품의 생산과 강도 평가에 있어서 시간과 비용의 절감 등 여러 가지 이점을 갖게 한다. 본 연구에서는 ANSYS 를 이용하여 승용차용 디쉬 타입과 스포크 타입의 휠을 3 차원 형상으로 모델링하고 구조해석과 피로해석을 수행하였다. 디쉬 타입과 스포크 타입에 대한 해석 결과를 비교해 보면, 디쉬 타입이 스포크 타입보다 변형이 적게 일어나고 최대등가응력도 작음을 알 수 있다. 그럼에도 불구하고, 스포크 타입이 경량과 우수한 냉각성능으로 인해 자주 사용되고 있다. 수명에 대한 피로 해석 결과, 알루미늄 휠이 스틸 휠보다 피로 저항력이 우수함을 보였다.