• 제목/요약/키워드: {\gamma})reaction$

검색결과 726건 처리시간 0.033초

${\beta},\;{\gamma}$-불포화카르복시산, 카르복시아미드와 니트릴 유도체의 합성과 이들의 광화학적 반응에 관한 연구 (Synthesis and Exploratory Photochemistry of ${\beta},\;{\gamma}$-unsaturated Carboxylic Acid, Carboxamide and Nitrile Derivatives)

  • ;채우기
    • 대한화학회지
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    • 제26권2호
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    • pp.99-106
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    • 1982
  • 1-아세틸-1-메틸-2-시클로펜텐 화합물의 케톤 Chromophore를 나트릴, 카르보시산, 아미드 등의 group으로 대치하여 이들의 광화학반응을 검토한 결과 케튼 Chromophore에서 볼 수 있는 1,3-Acyl shift나 ODPM 반응은 일어나지 않았고 광화학적 중합 및 환원반응등 Chromophore를 변화시키므로서 광화학반응에 큰 변화를 보여주었다. 1-Cyano-1-methyl-2-cyclohexene의 경우도 Ketone chromophore와 비교하여 광화학 반응을 검토하였다.

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Recognition of substrates by membrane potential

  • Yun, Kyu-sik;Tak, Tae-moon;Kim, Jong-ho
    • 한국막학회:학술대회논문집
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    • 한국막학회 1998년도 춘계 총회 및 학술발표회
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    • pp.31-35
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    • 1998
  • 1. INTRODUCTION : Recognition and binding of organic substrates by biological molecules are of vital importance in biophysics and biophysical chemistry. Most studies of the application focused on the development of biosensors, which detected reaction products generated by the binding between enzymes and substrates. Other types of biosensors in which membrane proteins (e.g., nicotinic acetylcholine receptor, auxin receptor ATPase, maltose bining protein, and glutmate receptor) were utilized as a receptor function were also developed. In the previous study[1], the shifts in membrane potential, caused by the injection of substrates into a permeation cell, were measured using immobilized glucose oxidase membranes. It was suggested that the reaction product was not the origin of the potential shifts, but the changes in the charge density in the membrane due to the binding between the enzyme and the substrates generated the potential shifts. In this study, $\gamma$-globulin was immobilized (entrapped) in a poly($\gamma$-amino acid) network, and the shifts in the membrane potential caused by the injection of some amino acids were investigated.

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Chlorosulfonated Polyethylene의 저온가황반응(低溫加黃反應) (Low Temperature Vulcanization of Chlorosulfonated Polyethylene)

  • 박근식;박성하;최세영
    • Elastomers and Composites
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    • 제27권4호
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    • pp.255-261
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    • 1992
  • Chlorosulfonated polyethylene(CSM) was moisture-cure after treating them with silane coupling agents such as ${\gamma}-mercapto$ propyl trimethoxy silane, ${\gamma}-glycidoxy$ propyl triethoxy silane and methyl triethoxy silane, 3-(trimethoxy silyl) propyl methacrylate and 3-thiocyanopropyl triethoxy silane. The cure reaction is composed two steps. The first is the reaction between chlorosulfonyl groups of CSM and silane coupling agents. The second is the formation of cross-links which are siloxane linkage. The linkage is formed by the condensation of silanol groups which are produced by the hydrolysis of alkoxysilyl groups. CSM was mixed with MPS etc., and dilaurate dilaurate as catalyst on two open mill and the compounds were lured in hot water at $70^{\circ}C$ Physical properties of moisture-cured CSM was measured. CSM was effectively moisture-cured and r-mercapto propyl trimethoxy silane and r-glycidoxy propyl trimethoxy silane were capable of the vulcanizing agents.

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Allicin Reduces Adhesion Molecules and NO Production Induced by γ-irradiation in Human Endothelial Cells

  • Son, Eun-Wha;Cho, Chul-Koo;Pyo, Suhkneung
    • IMMUNE NETWORK
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    • 제2권1호
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    • pp.6-11
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    • 2002
  • Background: Inflammation is a frequent reaction following therapeutic irradiation. Since the upregulation of adhesion molecules on endothelial cell surface is known to be associated with inflammation, the expression of adhesion molecules is an important therapeutic target. Methods: Treatment of human umbilical endothelial cells (HUVECs) with ${\gamma}$-irradiation (${\gamma}IR$) induces the expression of adhesion proteins such as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. Changes in the expression of these proteins on ${\gamma}$-irradiated HUVECs which had been treated previously with allicin were measured by ELISA. Results: In the present study, we demonstrate that allicin inhibits the ${\gamma}IR$ induced expression of ICAM-1, VCAM-1, and E-selectin on HUVEC in a dose-dependent manner. Allicin was also found to inhibit the ${\gamma}IR$ induced production of nitric oxide (NO). Conclusion: These data suggest that allicin has a therapeutic potential for the treatment of various inflammatory disorders associated with increase numbers of endothelial leukocyte adhesion molecules.

디메틸에테르의 직접반응 속도론 (Kinetics on Direct Synthesis Dimethyl Ether)

  • 조원일;최창우;백영순;노경호
    • 한국가스학회:학술대회논문집
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    • 한국가스학회 2005년도 추계학술발표회 논문집
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    • pp.83-87
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    • 2005
  • The kinetics of the direct synthesis of DME was studied under different conditions over a temperature range of $220\~280^{\circ}C$, syngas ratio $1.2\~ 3.0$ All experiment were carried out over hybrid catalyst, composed to a methanol synthesis catalyst (Cu/ZnO/$Al_2O_3$) and a dehydration Catalyst ($\gamma$-Al_2O_3$) The observed reaction rate qualitatively follows a Langmiur-Hinshellwood type of reaction mechanism. Such a mechanism is considered with three reaction, methanol synthesis, methanol dehydration and water gas shift reaction. From a surface reaction with dissociative adsorption of hydrogen, methanol and water, individual reaction rate was determined

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SiC-Al2O3 촉매를 이용한 CF4의 마이크로파 열분해 (Microwave Thermal Decomposition of CF4 using SiC-Al2O3)

  • 최성우
    • 한국환경과학회지
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    • 제22권9호
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    • pp.1097-1103
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    • 2013
  • Tetrafluoromethane($CF_4$) have been widely used as etching and chemical vapor deposition gases for semiconductor manufacturing processes. $CF_4$ decomposition efficiency using microwave system was carried out as a function of the microwave power, the reaction temperature, and the quantity of $Al_2O_3$ addition. High reaction temperature and addition of $Al_2O_3$ increased the $CF_4$ removal efficiencies and the $CO_2/CF_4$ ratio. When the SA30 (SiC+30wt%$Al_2O_3$) and SA50 (SiC+50wt%$Al_2O_3$) were used, complete $CF_4$ removal was achieved at $1000^{\circ}C$. The $CF_4$ was reacted with $Al_2O_3$ and by-products such as $CO_2/CF_4$ and $AlF_3$ were produced. Significant amount of by-product such as $AlF_3$ was identified by X-ray powder diffraction analysis. It also showed that the ${\gamma}-Al_2O_3$ was transformed to ${\alpha}-Al_2O_3$ after microwave thermal reaction.

소성과 황화반응에 따른 생석회의 비표면적 및 기공구조 변화 (Specific Surface Area and Pore Structure Changes of Calcined Lime with Calcination and Sulfation Reaction)

  • 강순국;정명규
    • 환경위생공학
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    • 제13권3호
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    • pp.19-29
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    • 1998
  • The calcination reactivity of limestone and physical property changes of calcined lime were investigated with a temperature($720~1000^{\circ}C$ under atmospheric gas($N_2$, $CO_2$) conditions. The mechanisms of mass transport in a lime matrix were represented by the evaporation and condensation (${\gamma}=1.7$) at $1000^{\circ}C$ and the volume diffusion (${\gamma}=2.7$) at $800^{\circ}C$, which was obtained by the specific surface area of calcined lime with sintering conditions. Also, the effect of physical property on the reactivity of sulfation reaction was determined by the changes of pore size with $lime-SO_2$ reaction in this work. The initial sulfation rate of calcined lime increased with increasing temperature, whereas the capture capacity of $SO_2$ exhibited a maximum value at $900^{\circ}C$. The pore volume of sulfated lime was decreased with increasing sulfation time, but the major pores shifted to the distribution of larger size at a temperature of $850{\;}~{\;}1000^{\circ}C$. The mean pore size of sulfated lime based on pore volume decreased gradually at $1000^{\circ}C$; however, it increased with sulfation time up to 40 min and rapidly decreased thereafter.

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Docosahexaenoic acid 함유 재구성지질의 효소적 합성 연구 (Lipase-Catalyzed Synthesis of DHA-Enriched Structured Lipid)

  • 조은진;조경현;이기택
    • 한국식품과학회지
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    • 제37권5호
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    • pp.709-712
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    • 2005
  • 조류(microalgae, from Schizochytrium sp.)로부터 DHA가 풍부하고 이취가 적은 지질을 획득하고 이를 옥수수유와 함께 반응기질로 이용하여 재구성지질을 합성하였다. 본 실험에 사용된 합성조건으로 oleic(17.3 mol%), linoleic(31.8 mol%), 그리고 docosahexaenoic acid(14.9 mol%)가 함유된 재구성지질을 합성하였다. ${\alpha}-,\;{\gamma}-$, 및 ${\delta}-tocopherol$의 총 함량은 0.059%로 분석되었고, 비누화 가(183.8) 및 요오드 가(201.8)를 측정하였다. 한편, 수행된 반응조건 및 반응시간동안 대부분의 반응은 6시간 내에 이루어 졌고, 그 상승폭은 3-6시간 사이에서 약 2.3배의 증가를 보이며 가장 크게 나타났다.

2-Phenylimino-1,3-thiazoline 염산염 유도체의 합성 (Synthesis of 2-phenylimino-1,3-thiazoline hydrochloride salts)

  • 한호규;남기달;신선호;마혜덕
    • 농약과학회지
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    • 제5권2호
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    • pp.13-17
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    • 2001
  • 새로운 살균제를 개발할 목적으로 새로운 2-phenylimino-1,3-thiazoline 유도체를 합성하였다. Ketone dimer를 염소와 반응시킨 다음 중간체 8a의 분리없이 benzylamine으로 처리하여 ${\gamma}-Chloro-{\beta}-keto$ benzylamide 10a를 얻었다. Methyl isothiocyanate와 aniline 유도체의 반응에서 얻은 thiourea 4를 10a와 acetone 용액 중에서 반응시켜 분리 불가능한 중간체 11 및 12를 거쳐 각각에 상응하는 2-phenylimino-1,3-thiazoline 유도체의 염산염 2를 얻었다. Thiourea 4의 phenyl기에 인접한 질소원자의 비공유 전자쌍의 도움으로 황원자의 친핵적 공격을 포함한 가능한 반응 mechanism을 논의하였다.

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