• 제목/요약/키워드: Natural park

검색결과 10,813건 처리시간 0.041초

THE NEW FINDING OF A LIGHT DEPENDENT $Ca^{2+}$ CHANNEL AND $Na^+-Ca^{2+}$ EXCHANGER IN THE VERTEBRATE RETINA (II)

  • Kim, Yun-Sook;Jung, Hyuk;Park, Chang-Suck;Woo, Suk-Hyang;Kim, Hyun-Jung;Kim, You-Young
    • Journal of Photoscience
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    • 제3권3호
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    • pp.133-136
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    • 1996
  • Calcium modulates the activity of guanylate cyclase and plays a key role in dark and light adaptation in the visual system. We have measured the Ca$^{2+}$, K$^+$ and Na$^+$ concentration in dark and light adapted bullfrog's (Rana catesbeiana) vitreous humor by using the atomic absorption spectrophotometer. The calcium concentration of the light adapted bullfrog's vitreous humor was higher than that of the dark adapted bullfrog's vitreous humor. This means that ion activity between the photoreceptor and vitreous humor side is light dependent and we have found that a Ca$^{2+}$ channel and Na$^+$ - Ca$^{2+}$ exchanger exist in the vitreous humor.

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섬유소분해균인 Trichoderma의 群體生長의 유도에 관하여 (Induction of Colonial Growth of the Cellulolytic Fungus, Genus Trichoderma)

  • 박희문;홍순우;하영칠
    • 미생물학회지
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    • 제22권3호
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    • pp.143-150
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    • 1984
  • The effect of growth inhibitors on colonial growth of cellulolytic fungus, genus Trichoderma, was investigated to develop a method for the effective screening of various auxotrophs and hypercellulolytic strains. As the results, it was revealed that non-ionic detergents such as Sodium deoxycholate and Triton X-100 were the better ones as a growth inhibitor than Oxgall which has been used to restrict the colony size in genus Trichoderma. Each individual colony remained distinct on minimal plate supplemented with 0.05% Triton X-100 for as long as two or more weeks. The screening of 150 to 200 colonies simultaneous on a single plate was possible in the presence of Triton X-100. The effect of Triton X-100 on simultaneous screening was higher than that of Oxgall by a factor of two.

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Effects of Reactive Compatibilizers on the Morphology and Properties of Natural Rubber/SiO2 Composites

  • Lee, Min Young;Park, Jin Young;Song, Ki Chan;Kim, Su Kyung
    • Elastomers and Composites
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    • 제51권2호
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    • pp.106-112
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    • 2016
  • Maleimidopropyltriethoxysilane grafted natural rubber (MISNR) was prepared by reaction of maleic anhydride grafted natural rubber and 3-aminopropyl triethoxysilane. MISNR was used as the compatibilizer of natural rubber/silica composites. The composites were prepared by two-step mixing procedures. The final mixtures were cured with optimum cure condition, which was established by a rheometer. Effects of the amounts of compatibilizer in the composites on the cure characteristics, morphology, thermal stability, and physical and mechanical behaviors were investigated. The composites having MISNR had shown cure characteristics and physical and mechanical properties superior to those without MISNR. Silica particles in the former appeared to be more uniform and reduced in size compared with the latter. The effects of the types of silica were also evaluated.

소형 비가열 실험을 이용한 원자로용기 외벽냉각시 용기와 단열재 사이의 자연순환 이상유동에 관한 연구 (A Non-Heating Small-Sclaed Experimental Study on the Two-Phase Natural Circulation Flow through an Annular Gap between Reactor Vessel and Insulation)

  • 하광순;박래준;조영로;김상백;김희동
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.1927-1932
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    • 2004
  • A 1/21.6 scaled non-heating experimental facility was prepared utilizing the results of a scaling analysis to simulate the APR1400 reactor and insulation system. The behaviors of the air bubble-induced two-phase natural circulation flow in the insulation gap were observed, and the liquid mass flow rates driven by natural circulation loop were measured by varying the injected air flow rate and distribution. As the injected air flow rates increased, the natural circulation flow rates also increased. Both the longitudinal and the latitudinal distributions of the injected air affected the natural circulation flow rates, especially, the longitudinal effect is more larger.

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리튬이온전지용 음극 활물질 하이브리드형 탄소의 전기화학적 특성 (The electrochemical properties of hybrid carbon as a negative active material for lithium ion batteries)

  • 양동복;박용필
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 제6회 학술대회 논문집 일렉트렛트 및 응용기술연구회
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    • pp.27-30
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    • 2004
  • Different types of hybrid negative materials on pitch based carbon and natural graphite for lithium ion batteries were studied. Two types of active materials were prepared, that is, pitch based graphite carbon, and pitch based carbon impregnating natural graphite. The specific capacity, capacity recovery in high temperature condition, and other electrochemical properties were achieved for these materials. We found that addition of natural graphite type to the pitch based carbon can significant1y improve the specific capacity and interfacial resistance. However, use of natural graphite will cause a serious capacity loss in the high temperature condition owing to its increasing interface resistance. The specific capacity ranged from 321 to 348 mAh/g and the maximum specific capacity was obtained in the case of pitch based carbon impregnating natural graphite.

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천연 식품첨가물 연구개발 동향분석 (Analysis of research trend in natural food additives)

  • 이현희;정재연;박정민
    • 식품과학과 산업
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    • 제49권4호
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    • pp.82-93
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    • 2016
  • Although the development of food technology is relatively fast, it's application is very broad. So, it is necessary that quantitative analysis method can be introduced in analysing of research trends and implication of research themes. Most countries do not classify in food additives as synthesis or natural. However, the use of natural food additives should be recommended by considering about health safety. In this regard, quantitative analysis based on bibliographic information of patents and papers is vital to analyse the trend of research on natural food additives. The data regarding with natural food additives was assigned patents and published papers in the world from 1996 to March 2016 and Thomson Innovation, analysis program was provided by Thomson reuters.