• Title/Summary/Keyword: 저온:-45$^{\circ}C$

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Negative metal on ion beam 증착방법을 이용한 TFT-LCD용 저온 poly-Si 박막 성장

  • 전철호;김현숙;권오진;박종윤
    • Proceedings of the Korean Vacuum Society Conference
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    • 1999.07a
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    • pp.70-70
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    • 1999
  • 현재 TFT-LCD에서 주류를 이루고 있는 a-Si 으로는 SXGA급 이상의 LCD를 구현하는 데 그 자체 이동도(0.4~1.0cm2/Vs)의 한계 때문에 poly-Si(100~300cm2/Vs)을 사용하지 않을 수 없다. Poly-Si을 성장시키는 방법으로는 PECVD 방법, SPC 방법, Laser Annealing 방법등이 있으나 아직 이 모든 방법으로는 성장박막의 질, 즉 이동도, 균일성 등이 만족스럽지 못하다. 그 중에서 Laser Annealing 방법으로 저온에서 가장 좋은 막질을 얻고 있으나 균일성 및 생산성 향상면에서 여려움이 제기되고 있다. 따라서 차세대 TFT-LCD의 핵심소재인 poly-Si을 저온에서 유리기판위에 양질의 박막으로 성장시킬 수 있는 박막성장법이 절실하다. 본 연구에서 사용된 실리콘 이온 증착법은 Sidl 이온 상태로 직접 증착되므로 이온 에너지가 직접 결합에 기여하게 되고 동시에 이온 에너지는 전기적으로 제어되므로 박막 형성에 필요한 정정 에너지를 공급할 수 있다. 따라서 종래의 열에너지만을 이용한 방법보다 훨씬 낮은 온도에서 박막을 성장시킬 수 있었다. 3kV의 Cs+에 의해 sputter 된 Si beam- 에너지를 20~100eV, Si- flux를 약 4$\mu$A.cm2로 조절하며, 기판온도 300~45$0^{\circ}C$에서 각각 제조하였다. 30$0^{\circ}C$, 20~50eV에서 poly-Si임을 XRD 분석으로 확인 할 수 있었다.

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Characteristics of Processed Food for Improvement Utilization of Sweet Persimmon (단감의 이용성 증진을 위한 특성 검토)

  • Choi, Yoon-Hee;Kim, Eun-Mi;Cho, Yong-Sik;Park, Shin-Young;Yang, Jeong-Min
    • Proceedings of the Korean Society of Community Living Science Conference
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    • 2009.09a
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    • pp.88-88
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    • 2009
  • 단감은 우리나라가 세계에서 가장 많은 양을 생산하는 대표 과일로 과잉생산과 수확기에 일시적인 홍수출하로 인한 가격이 하락하고, 기상이변에 의한 비상품 과일의 생산이 많아지나 전량 폐기되고 있으며, 유통 및 저장 중에 연화현상과 생리적장애로 품질이 저하되어 경제적 손실이 발생되므로 안정적 생산과 소비를 위하여 다양한 형태의 식품개발이 절실히 요구된다. 국내 감 생산량은 352,822톤이며 이 중 떫은감은 146,233톤(41.45%), 단감은 206,589톤(58.55%)으로 단감 생산량이 떫은감에 비하여 많으며 국내 단감 생산지는 진영, 순천, 문산, 담양, 장성 등 집단화 되어 있고, 원료확보가 유리하나 저장은 수확기인 10월 중순, PE필름 봉지에 넣고 밀봉하여 박스 등에 넣어 $0{\sim}1^{\circ}C$의 저온저장고에 이듬해 4월 중순까지 6개월 정도 저장 가능하나 저장비용이 많이 들고, 4월 이후에는 생리적 장해로 보관이 어렵다. 단감은 다른 과일에 비하여 높은 감미와 비타민 A, 비타민 B1, 비타민 C, 식이섬유 및 리코핀 성분이 다량 함유되어 있고, 노화와 암 발생을 억제하는 폴리페놀물질이 풍부하여 건강 기능성 과일로 알려져 있다. 본 연구에서는 시중에서 구입한 단감의 저온저장 중 감모율 및 이용성 구명을 위하여 관련특성을 검토하였다. 단감을 3월에 구입하여 $5^{\circ}C$에 저온저장하여 보관기간별 감모율을 조사하였고, 단감의 전 처리 후 당도, pH, 색도, 수분함량 등을 조사하였다. 3월에 시중에서 구입하여 PE필름에 봉한 채 종이박스 넣어 $5^{\circ}C{\pm}2$ 저온저장고에 저장하여 1개월 후에 조사한 결과 정상과가 75.47%, 25%미만 장해과가 14.37%, 50%이상 장해과가 10.16% 이었고, 2개월 후는 정상과가 41.52%, 25%미만 장해과가 42.88%, 50%이상 장해과가 15.61%이었다. 단감을 꼭지제거, 박피, 제핵 후 절단하여 파쇄 후의 당도는 14.8 $^{\circ}Brix$, pH는 6.0, 수분은 56.7%, 색도 L값은 39.8, a값이 12.6, b값이 22.7이었다. 파쇄한 단감을 $-20^{\circ}C$에 1차 냉동하여 해동 후 당도는 냉동 전 $14.8^{\circ}Brix$에서 $14.2^{\circ}Brix$로, 2차 냉동 해동 후는 $12.6^{\circ}Brix$로 감소하였으며, 색도 L값과 a값 및 b값은 냉동 전에 비하여 감소하였고, 수분함량은 냉동 전 64.4%, 1차 냉동 해동 후에 82.78%, 2차 냉동 해동 후에는 84.09%로 증가하였다.

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Starting of Farming Diesel Engines According to Characteristics of Light Oil at Low Temperature (경유의 저온특성에 따른 농용 디젤엔진의 저온시동성)

  • 신승엽;김학주;이용복;김병갑;윤진하;김기택;양대준
    • Journal of Biosystems Engineering
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    • v.28 no.1
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    • pp.11-18
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    • 2003
  • This study was carried cut to get basic data of troubles in starting and supply of farm diesel engines in cold winter. The results of the study are summarized as follows: 1. As the result of farm survey. the proportions of farms which had starting problems or troubles in fuel supply in cold winter for the last 5 years were 38% for the farms with power-tillers and 32% for the farms with tractors. Most of the farms which had starting problems or troubles in fuel supply in cold winter used light oil for summer. spring or fall rather than for winter. 2. As the result of fuel supply test, fuel supply was stopped at -6$^{\circ}C$ and -18$^{\circ}C$ for summer light oil and winter light oil. respectively 3. The lowest temperatures of winter light oil for starting engine were -7.5$^{\circ}C$ for power-tiller. -12.5$^{\circ}C$ for tractor of 38ps, and -17.5$^{\circ}C$ for tractor of 45ps. which were 5~7.5$^{\circ}C$ lower than that of summer light oil. 4. The performance of engine starting and the trouble of fuel supply system at lower temperature were significantly improved by using winter hight oil rather than summer light oil.

Development of Temperature Control System to use in Building Heating of low Temperature Heat of PEMFC (고분자전해질 연료전지의 중저온 열원을 건물난방에 이용하기 위한 온도 제어장치 개발)

  • Cha, Kwang-Seok;Kim, Hway-Suh
    • Plant Journal
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    • v.10 no.3
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    • pp.45-51
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    • 2014
  • This study performs several experiments on a newly developed temperature safety system that can be used for residential building heating systems, the heat source of which is derived from a conventional fuel cell. Prior to this, the hot water made from a fuel cell was not used in residential housing but just went to waste. The present safety system is installed in the current underfloor heating system. At first we used the CFD technique to develop a new heat exchanger. The fuel cell must satisfy the thermal conditions of the inlet temperature being $55^{\circ}C$ and the outlet temperature being $60^{\circ}C$. But variations in weather cause fluctuations in the heating water temperature. The experimental results show our new system capable of maintaining the temperature difference within a ${\pm}0.5^{\circ}C$ range. So we believe that our new PFMFC fuel cell stack array is a good candidate for being used in residential heating systems.

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Influence of Low Temperature at Reproductive Stage on Rice Grain Quality (생식생장기 저온이 미질에 미치는 영향)

  • Jeong, Eung-Gi;Choi, Hae-Chune;Hong, Ha-Cheol;Moon, Huhn-Pal;Shin, Young-Beom
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.42 no.6
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    • pp.805-809
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    • 1997
  • The influence of cool temperature occurred during the booting stage in 1993 on quality of rice grain was compared with that in favorable weather of 1994. The mean and minimum air temperatures during the reproductive growth stage at the paddy field of Jinbu Substation, National Crop Experiment Station were 2.2~7.4$^{\circ}C$ and 2.0~8.9$^{\circ}C$ lower respectively in 1993 compared to those of 1994. Grain fertility and brown rice yield were 11.8% and 0.4t /ha, and 84.3% and 5.5t /ha in 1993 and 1994, respectively. There was no difference in amylose content between two years. However, protein content of brown rice in 1994 were 1.6% lower than that of 1993. There was no difference in alkali digestion value of milled rice between two years. Gel consistency of rice flour was 45mm in 1993 and 59mm in 1994. Amylogram characteristics of rice flour produced in 1993 showed lower peak hot, cool, and breakdown viscosities, and higher consistency and setback viscosities. The palatability of cooked rice by sensory panel test was considerably better in 1994 rice than in the rice of cool year.

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Some Factors Affecting Growth of Didymocladium ternatum and Chemical Control of Mildew Diseases in Cultivation of Agaricus bisporus (양송이 부패병원균(腐敗病原菌)의 발병요인(發病要因) 및 방제(防除)에 관한 연구(硏究))

  • Kim, Gang-Po;Kim, Tae-San
    • The Korean Journal of Mycology
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    • v.10 no.4
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    • pp.173-176
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    • 1982
  • In cultivating the mushroom, there are important several mushroom diseases including Mildew disease, Didymocladium ternatum. Studies on some factors affecting growth of D. ternatum and its chemical control were carried out. The optimum temperature for mycelial growth of D. ternatum was $15{\sim}20^{\circ}C,$ lower than that of Agaricus bisporus. Infection was very severe when it was infected between at casing and at the end of the first flush. Mycelial thermal death occurred at $50^{\circ}C$ when it was treated for more than 20 minutes. For spore, $50^{\circ}C$ for 60 minutes and $60^{\circ}C$ for 20 minutes were required respectively as a thermal death point. Benlate, Homai and Dithane M-45 were selected as effective chemicals for controlling this disease.

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Disinfection effects of heat- and cold-treatment and UV-irradiation on campylobacter jejuni (고온 및 저온처리와 자외선조사에 의한 campylobacterjejuni의 살균효과)

  • 김치경;임선희;윤만석;오학식;조민기
    • Korean Journal of Microbiology
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    • v.27 no.3
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    • pp.291-296
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    • 1989
  • Campylobacter jejuni was studied for its disinfection by heat-and cold-treatment and UV-irradiation. When C. jejuni was treated by heat, no viable cell was found after 10 min treatment at $55^{\circ}C$, whereas small fraction of cell population was survived after 60 min treatment at $45^{\circ}C$ and $50^{\circ}C$. When they were treated by cold temperature for 30 days, no cell was survived at -$23^{\circ}C$ but about 4 log of the cells were survived at both temperature of $4^{\circ}C$ and -$40^{\circ}C$. When the organisms were UV-irradiated, thier survival rates were proportionally varied to the distance of irradiation. The scanning electron microscopic studies of C. jejuni cells treated by the disinfecting agents revealed that shapes of thecells were deformed from spiral rod into spherical form. The heat-treated cells showed rough and damaged surface on the scanning electron micrographs. In the heat-treated cells, some proteins of high molecular weight appeared to become accumulated in the electrophoretic analysis. The DNAs extracted from the cells treated with the physical agents showed some differences in agarose gel electrophoresis, comparing those of normal cells.

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Effect of Hvperkalemia and Hypothermia on Endothelium-dependent Relaxation of the Rat Aorta (고칼륨과 저온이 흰쥐 대동맥의 내피세포의존성이 완능에 미치는 영향)

  • 이응배;전상훈
    • Journal of Chest Surgery
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    • v.29 no.12
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    • pp.1299-1305
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    • 1996
  • The rat thoracic aorta was harvested to determine whether either hyperkalemla or hypothermia impairs the endothelium-dependent re axation of the vascular smooth muscle. Isolated thoracic aorta segments were studied in five groups(n=10 in each group). In group I(control), the isolated aortic seglnents were suspended in organ bath without any intervention. In group ll(endotheilum removAl). the endothelium of the aortic segment was removed by gentle rubbing of the intimal surface with a pair of forceps. In group III(457), IV(4mST), and V(3757), the aortic segments were exposed for 45minutes to 4$^{\circ}C$ St. Thomas hospital cardioplegic solution(57 : NaCl, 144.3; KCI, 19.6, MgCl:, 15.7 : CaCl, 2.2 mmol/L).4$^{\circ}C$ modified St. Thomas hospital cardioplegic solution(NaCl, 144.3 : KCI. 140.0 : MgCl:, 15.7; CaCl:. 2.2 mmol/L). and 37$^{\circ}C$ 57, before suspending in the organ bath, respectively. Then, aorta segments were suspended in organ baths(physiologic salt solution, 37$^{\circ}C$, 95% oxygen and 5% carbon dioxide) for Isometric tension recording. The vasodilatation to acetylcholine (10-2 to 10-2mol/L) was not impaired in control, 457, 4mST, nd 3757 groups. The vasodilatation to acetylcholine was impaired in endothelium removal group. The vasodilatation to sodium nitroprusslde (10-2 to 10-2 mol/L) was not impaired in all groups. In conclusion, both hyperkalemia and hypothermia do not alter irreversibly the function of the rondothelium of the thoracic aorta of the rat.

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Pantoea spp.에서 분리한 호냉성 ${\beta}-Galactosidase$의 생화학적 특성 및 우유 내 유당분해 활성

  • Choe, Jae-Won;Lee, Seung-Bae;Choe, Seok-Ho
    • Proceedings of the Korean Society for Food Science of Animal Resources Conference
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    • 2004.10a
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    • pp.384-387
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    • 2004
  • 겨울철 토양에서 ${\beta}-Galactosidase$를 생산하는 균주를 분리하였으며 동정한 결과 그람 음성 간균이고 Pantoea spp. 로 확인되었다. Pantoea spp. 균주의 세포 추출물로부터 DEAE-Sephacel chromatography와 affinity chromatography를 이용하여 ${\beta}-Galactosidase$를 분리하였다. Pantoea spp. 의 ${\beta}-Galactosidase$의 반응 최적 온도는 $45^{\circ}C$이이고 최적 pH는 $5.5{\sim}7.5$이고 열안정성을 조사한 결과 $45^{\circ}C$이상의 온도에서 불활성 되는 것으로 나타났고 E. coli에서 분리된 효소보다 저온에서의 활력이 좋았지만 상업적인 효소인 Kluyveromyces lactis (Validase) 보다는 낮았다.

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Low Temperature Synthesis of Willemite Powder (Willemite 분말의 저온합성)

  • Son, Se-Gu;Lee, Ji-Hyeon;Lee, Jeong-Mi;Kim, Young-Do
    • Journal of the Korean Ceramic Society
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    • v.45 no.7
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    • pp.401-404
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    • 2008
  • Willemite ($Zn_2SiO_4$) are a wide range of applications such as a phosphor host and an important crystalline phase in glass ceramics, electrical insulators, glazes, and pigments. In this study, Willemite precursors were synthesized with zinc silicate gels from mixture of zinc nitrate solution and various sodium silicate solution by the geopolymer technique. To examine the crystallization behavior, precursors were have been monitored by the XRD. A pure willemite phase was obtained at $900^{\circ}C$. TEM investigations revealed that the sample with 50 nm particle size was obtained via heat-treated at $900^{\circ}C$ for W-3.