• Title/Summary/Keyword: EVA film

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Structural Analysis of Cheju-style Plastic Greenhouse Model for Crop Growing Based on the Wind Load (풍하중을 고려한 제주형 작물재배용 비닐하우스모델의 구조해석)

  • 민창식;김용호;권기린
    • Journal of Bio-Environment Control
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    • v.7 no.3
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    • pp.181-190
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    • 1998
  • An elastic analysis under wind load was performed for the double layered plastic greenhouse model developed particularly for minimizing damages under typhoons at Cheju Citrus Research institute in Seagipo city. General EVA film was used for the inner covering and the developed special film which would break the wind pressure down was used for the outer covering. The wind tunnel test showed this special film reduced the wind speed up to 86 to 98% under well controlled situation. Based on the elastic analysis performed in the study, the behavior of the greenhouse was changed significantly due to the boundary conditions. Not like other researchers before we applied dead load of the concrete support to the ground pipe and fixed support boundary conditions at the 4 corner pipes. The analysis shows that the greenhouse was lifted and pulled the pipe out of the ground due to the sucking wind pressure. The behavior of the greenhouse was quite similar to that one real greenhouse failure. Therefore, not only we need to find the realistic boundary conditions for the supports, but also need to find how to rest the pipe supports on the ground without economic loss.

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Hybridization of solar cell and thermoelectric device and its characteristics (태양전지-열전통소자의 제조 및 그 특성)

  • Kim, Sung-Jin;Park, Sung-Bum;Jin, Mi-Jin;Cho, Soo-Jeong;Choi, Soon-Hee;Choi, Byung-Ho;Jeong, Soon-Wook
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.391-391
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    • 2009
  • 결정질 실리콘 태양전지의 통합화에는 최근 열전소자와의 통합화를 통한 연구가 진행이 활발해지고 있으며, 이 경우 주로 태양전지와 열전소자의 박막화를 이용한 방법이 주를 이루고 있다. 이 경우 모듈화를 위해서는 in-line system을 이용한 방법이 강구되고 있으며, 솔라셀과 열전소자를 Tandem 구조에 적용할 경우 미국의 연구소 및 대학의 simulation에 의하면 에너지변화효율을 65%까지 올릴 수 있다는 보고가 되어 지고 있다. 그러나 이 경우 새로운 시설 및 기술의 확보에 큰 자본을 투입해야하는 경제적인 문제가 있다. 또한 최근의 silicon 결정질 solar cell 원료의 가격이 1년전에 비해 1/4로 급격하게 떨어진다는 점에서 박막화에 대한 투자는 일부나라에서 정체의 수준까지 다다르게 되었다. 따라서 본 연구에서는 40X40X3mm 크기의 열전소자를 결정질 silicon 솔라셀에 부착하는 방법으로 통합화를 시도하였으며, 모듈화에는 EVA film을 사용하지 않는 방법을 이용한 batch 법으로 모듈을 제작하고, 그 특성을 비교하였다. 그 결과 통합된 솔라셀-열전 모듈의 에너지변환효율은 동일한 크기의 솔라셀을 사용하여 제작한 모듈에 비해서 $60^{\circ}C$에서 공냉을 이용하여 측정한 결과 약 8% 개선효과가 있었으며, 보다 더 나은 결과를 도출하기위해 열전소자쪽에 냉각수나 냉각판을 설치하는 시도가 요구된다.

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A Study on the Temperature Change of Green House using Aerogel (에어로젤을 사용한 시설하우스의 온도 변화에 대한 연구)

  • Yang, Ji-Ung;Lee, Eun-Suk;Ko, Joon-Young;Kim, Won-Kyung;Byun, Jae-Young;Park, Jin-Gyu;Choi, Won-Sik
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.6_2
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    • pp.1067-1074
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    • 2020
  • Green houses provide a more conditioned and warmer environment than the outside environment due to insulation. Currently used insulation materials include soft film (PVC, PE, EVA), foamed PE sheet, non-woven fabric, reflective film, and multi-layer insulation curtain, but there are many disadvantages and to compensate for this, silica aerogel insulation material with excellent warmth, light weight, and small volume Research using is in progress. In this study, the temperature change of the quadruple-structure green house and the temperature change in the dual-structure green house of soft film and silica airgel were investigated. The daytime temperature change was highest in A and A2 (soft film) at 10 to 16:00 after sunrise, but showed the lowest temperature at 17 to 18:00, which is the sunset time, showing the greatest change. The airgels of D and D2 showed the smallest change in temperature after sunrise and right after sunset. That is, it can be said that the airgel is hardly affected by external temperature. The temperature change at night was highest in D and D2 (aerogel) for both quadruple and dual structures. The temperature at night was measured higher in the quadruple structure than in the double structure. As for the ratio of the internal temperature to the external temperature for the quadruple structure and the double structure, D (aerogel) was not affected by the external temperature during the day in the quadruple structure and the double structure. D (Aerogel) seems to be able to reduce the damage caused by high temperatures in summer due to the high thermal insulation effect of the airgel, as the temperature rises above 4℃ at night. And in winter, it helps to save heating costs due to less heat emitted to the outside.

Current Status and Utilization Technology of End-of-Life Photovoltaic Modules (태양광 폐 모듈의 처리현황 및 실용화 기술)

  • Cho, Jai Young;Park, Areum;Yun, Hyun Mok;Jun, Yun-Su;Kim, Joon Soo
    • Resources Recycling
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    • v.29 no.4
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    • pp.15-30
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    • 2020
  • Recently, it is increasing a amount of installed solar-cell rapidly, and end-of-life photovoltaic(ELP) modules are generated in according to the reduction of cell efficiency largely. Recycling of ELP modules are begun at an advanced nation already, but there are bring about environmental contamination and resource recovery problems owing to not treated ELP modules because of economic cost completely. First of all, there were researched basic study for treatment conditions of used solar cell inspection, dismantling of aluminum frame, crushing / grinding & separation of tempered glass, removal of back sheet & EVA film, leaching & precipitation recovery of valuable metals and treatment of waste water. Therefore, we establish optimum conditions through carried out of designed apparatus, installation of equipment, test operation & trouble shooting in scale of 1ton/day pilot plant test. Following to economic review, it does have the economic efficiency until to the case of tempered glass recovery, but does not have the economic value in case of total processes until to recover the valuable metals. However, there are guaranteed economic value if we are gained a large amount of the expenses through EPR supported system. It was confirmed the commercialized possibility of ELP modules recycling if there were established on the collecting ELP modules, reusing criteria, economical technology, enactment of directives and enforcement of EPR supported system efficiently.

A Study on Thermal Characteristics of Carbon-Organic Surface Heating Element with Electrodeless Lamp of a Freezer (냉동고 무전극램프 적용 탄소-유기소재 면상발열체의 열 특성에 관한 연구)

  • Lee, Min-Sang;Back, Seong-Hun;Kang, Sung-Soo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.1
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    • pp.1-10
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    • 2020
  • This study deals with the fabrication and thermal characterization of planar heating elements attached to the backside of the reflector used in the electrodeless lamp of a freezer. We tried to solve the problem of the local heat generation of the linear heating element that occurs about 50℃. The homogeneous dispersion and manufacturing excellence of the planar heating element produced were confirmed through SEM and EDS. In addition, the test specimens was prepared according to the change in the ratio of carbon fiber to the basis weight of the planar heating element, and a sample having a basis weight of 50g/㎡ having a content ratio of carbon fiber of 70% was selected. That sample showed low surface resistance of 4.3Ω/sq and high temperature of about 81℃ at 6V. Durability was confirmed by performing repeated bending evaluation of 3000 cycles for the sample. Large area test specimens were prepared to be applied to the actual reflector, insulated by EVA film and analyzed for their thermal characteristics. From 13V application, the temperature of the linear heating element was higher than 50℃ and the average temperature of 68℃ was maximum at 18V.

MBE growth of topological insulator $Bi_2Se_3$ films on Si(111) substrate

  • Kim, Yong-Seung;Bansa, Namrata;Edrey, Eliav;Brahlek, Mathew;Horibe, Yoichi;Iida, Keiko;Tanimura, Makoto;Li, Guo-Hong;Feng, Tian;Lee, Hang-Dong;Gustafsson, Torgny;Andrei, Eva;Cheong, Sang-Wook;Oh, Seong-Shik
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.59-59
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    • 2011
  • We will report atomically sharp epitaxial growth of $Bi_2Se_3$ three-dimensional topological insulator films on Si(111) substrate with molecular beam epitaxy (MBE). It was achieved by employing two step growth temperatures to prevent any formation of second phase, like as $SiSe_2$ clusters, between $Bi_2Se_3$ and Si substrate at the early stage of growth. The growth rate was determined completely by Bi flux and the Bi:Se flux ratio was kept ~1:15. The second-phase-free atomically sharp interface was verified by RHEED, TEM and XRD. Based on the RHEED analysis, the lattice constant of $Bi_2Se_3$ relaxed to its bulk value during the first quintuple layer implying the absence of strain from the substrate. Single-crystalline XRD peaks of $Bi_2Se_3$ were observed in films as thin as 4 QL. TEM shows full epitaxial structure of $Bi_2Se_3$ film down to the first quintuple layer without any second phases. This growth method was used to grow high quality epitaxial $Bi_2Se_3$ films from 3 QL to 3600 QL. The magneto-transport properties of these thin films show a robust 2D surface state which is thickness independent.

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An Experiment Study on Manufacturing process of BIPV Module (BIPV모듈의 제조공정에 관한 실험적 연구)

  • An, Youngsub;Kim, Sungtae;Lee, Sungjin;Yoon, Jongho
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.54-54
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    • 2010
  • In this study, the correlation between temperature and the gel-content of the module were analyzed through experiments. Amorphous thin-film solar cell used in this experiment has a visible light transmission performance of 10%. In addition, ethylene vinyl acetate(EVA) film and the clear glass have been used for the modulation. The most important process is to laminate the module in the manufacturing process of BIPV(Building integrated photovoltaic) module. Setting parameters of laminator in the lamination process are temperature, pressure and time. Setting conditions significantly affect the durability, watertightness and airtightness of module. The most important factor in the setting parameters is temperature to satisfy the gel-contents. The bottom and top surface temperature of module are measured according to setting temperature of laminator. The results showed $145^{\circ}C$ of max temperature of the bottom surface and $128^{\circ}C$ of max temperature of top surface on the module at the temperature condition of $160^{\circ}C$. And at the another temperature condition of laminator with $150^{\circ}C$, the max temperature do bottom and top are $117^{\circ}C$ and $134^{\circ}C$ respectively. The temperature difference between bottom and top of the module occurred, that is because heat has been blocked by the clear glass and the bottom of the cells absorb the heat from the laminator. In this particular, the temperature difference between setting temperature of the laminator and the surface temperature of the module showed $15^{\circ}C$, because the heat of laminator plate is transferred to the surface of the module and heat is lost at this time. As a results, gel-content showed 94.8%, 88.7% and 81.7% respectively according to the setting temperature $155^{\circ}C$, $150^{\circ}C$ and $145^{\circ}C$ of the laminator. In conclusion, the surface temperature of module increases, the gel-contents is relatively increased. But if the laminator plate temperature is too high, the gel-content shows rather decline in performance. Furthermore, the temperature difference between setting temperature and the surface temperature of the module is affected by laminating machine itself and the temperature of module should be considered when setting the laminator.

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The Movie by Jung of Individuation (융의 개성화이론으로 읽는 영화<케빈에 대하여>)

  • Choi, Young-Mi;Jo, I-Un
    • The Journal of the Korea Contents Association
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    • v.18 no.3
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    • pp.361-368
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    • 2018
  • This study analyzes movie by individualiztion theory of JUNG. It is about the mother and the boy who killed the family and a lot of people based on the original novel of the same name. Movies based on maternal love express the maternal sublime devoted to their children, or act as a genre film that introduces maternity even against social myth or ethics. It expresses the desire of a woman to clash with maternity and raises questions about maternal ideology.The maternal ideology was a modern product had fixed sex role in industrialized societies.As a resukt, maternal love is identified with femininity unlike paternal love. Women are emphasized to be responsible for raising safe social members beyond individual responsibility. The movie develop story about crime that occurred in motherson relationship which lacks attachment formation in fostering process. This is not a recuurence of the maternal ideology of mother who miscarried child because she lacked motherhood. Mother Eva projected a conflict that is between maternal ideology and her desire on motheson relationship.Son Kevin also experiences a projection that influenced his persona through his mother. In this paper, I analyze through JUNG's individualization theory that The characters face their projected ego and realize self-fulfillment by searching of their own life goal out of external role or ideal.