• Title/Summary/Keyword: 이성화

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A Study on the Racemization of Amino acids and its Separation with GC, GC/MS and HPLC (아미노산의 광학이성화 및 GC, GC/MS, HPLC에 의한 광학이성질체의 분리에 관한 연구)

  • Rhee, Jae-Seong;Hong, Jong-Ki;Eo, Yun-Woo;Kim, Taek-Jae
    • Analytical Science and Technology
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    • v.7 no.1
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    • pp.41-52
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    • 1994
  • The importance of separation comes from demands on study for exact effect of synthetic drugs and the reactivity of enantiomer in biological system. Racemization rate was measured under the influence of heat, acid, UV-light, enzyme(trypsin) and 6N-HCl at $105^{\circ}C$ on alanine, threonine, isoleucine, lecuine, aspartic acid, methionine, glutamic acid, tyrosine. The method for the identification of overlapped amino acids with GC was developed from the close study of fragmentation pattern with mass spectrometry. With cyclodextrin bonded phase by HPLC, the separation of dansyl amino acid was tested for compartison.

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Development of Jet-Fuel Using Petroleum Displacement Resources (석유대체자원을 이용한 항공유제조기술)

  • Jeong, Soon-Yong;Kim, Chul-Ung;Jeong, Kwang-Eun;Koh, Jae-Cheon;Chae, Ho-Jeong;Kim, Tae-Wan;Park, Hyun-Joo;Lee, Sang-Bong;Han, Jeong-Sik;Jeong, Byung-Hun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.307-310
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    • 2010
  • The research for production of jet fuel from petroleum displacement resources such as bio-mass, coal, natural gas mainly consists of three sub-research areas; the fisrt step is the pretreatment for producing a synthetic gas, and the next step is the Fischer-Trophsh reaction process for making hydrocarbons. The last is the upgrading technology for the hydrocarbons to fit a jet fuel specification via cracking and isomerization reactions. This talk presents reaserch trends and main technologies for production of jet fuel derived from petroleum displacement resources.

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Photo-induced birefringence on azobenzene type polymer film for optical memory (광정보저장용 아조벤젠 타입 고분자에서의 광유도 복굴절)

  • 여세연;이현기;황의중;오차환;송석호;김필수;한양규
    • Proceedings of the Optical Society of Korea Conference
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    • 2002.07a
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    • pp.132-133
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    • 2002
  • 아조벤젠 고분자는 가역적 광이성화 과정에 의한 광유도 복굴절을 일으키는 물질로 광정보저장용 및 광소자용 매질로서 많은 연구가 이루어져 왔다. 일반적으로 아조벤젠 고분자는 rod-like 형태의 안정한 trans 상과 banana-like 형태의 준 안정한 cis 상의 이성체가 존재하고 이 두 이성체는 광에 의해 여기 되어 서로 다른 이성체로의 이성화가 일어나는데, 특히 막대 모양의 trans 상의 분자가 여기 시키는 광의 편광 방향에 수직으로 정렬하면서 복굴절이 유도되며 cis 상의 분자는 복굴절의 유도와 무관하다고 알려져 있다. (중략)

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A Feminist Psychological Analysis on the Playful Embracement of Boys' Love Manga (여성심리학 관점에서 분석한 남성동성애만화(Boys' Love manga)의 유희적 수용)

  • Yang, Sungeun
    • The Journal of the Korea Contents Association
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    • v.18 no.9
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    • pp.510-520
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    • 2018
  • This study explored the phenomenon of heterosexual women embracing Boys' Love manga within the heteronormativity context from a feminist psychological perspective. Specifically, the issue of genre characteristics of Boys' Love manga, women's psychological mechanism of reading Boys' Love manga, and the functions and effects of embracing Boys' Love manga were discussed. As a theoretical framework of analysis, I started from the classical psychoanalysis and critically adopted the concepts of the various camps of feminism, queer theory, and Huizinga's Homo Rudens. The results show that Boys' Love manga can be classified as a sub-category of the romance genre, which fulfills heterosexual women's desires of eternal love and equal partnership. From these wish-fulfilling fantasies, heterosexual women attempt to be decontextualized from the heteropatriarchism, to enjoy distancing and voyeuristic separation from the characters in the texts, and to disturb the dichotomous gender system through gender reversal identification. These processes, which can be regarded as a women's play challenging sexual rigorism, ultimately bring about an awareness of the female sexual subjectivity.

Studies on the glucose isomerizing enzyme. (Part IV) -On the enzymatic properties and treating conditions for high activity containing cells- (포도당(葡萄糖) 이성화(異性化) 효소(酵素)에 관(關)한 연구(硏究) (제4보(第四報)) -효소학적(酵素學的) 성질(性質)및 효소생성능(酵素生成能)에 대(對)하여-)

  • Rhee, In-Koo;Seu, Jung-Hwn
    • Applied Biological Chemistry
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    • v.12
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    • pp.69-74
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    • 1969
  • This glucose isomerizing enzyme, which Actinomyces sp. (strain, K-17) produced, was inhibited by citrate, oxalate, ethylene diamine tetraacetic acid and cysteine on the enzyme reaction. This enzyme isomerized xylose to ketose as well as glucose. The Michaelis constant of this enzyme was $7.2X\;10^{-1}M.$. on D-glucose. The enzyme activity of intact cells which were harvested in the none xylose containing medium was very weak. If these intact cells of low activity were treated in the buffered xylose solution, its activity was considerably increased. After fifteen hours at $32^{\circ}C$. on xylose treatment, the enzyme activity was increased to equilibrium and the treating condition was proper at neutral pH and in aerobic state. The adequate concentration of xylose on the treatment was about 0.5 percent.

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Isomerization of Endo-tetrahydrodicyclopentadiene over Y Zeolite Catalysts (Y 제올라이트 촉매 상에서 Endo-Tetrahydrodicyclopentadiene의 이성화 반응)

  • Kim, Jinhan;Kim, Ji-Yun;Park, Eunseo;Han, Jeongsik;Kwon, Tae Soo;Park, Young-Kwon;Jeon, Jong-Ki
    • Applied Chemistry for Engineering
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    • v.25 no.1
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    • pp.66-71
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    • 2014
  • Synthesis of exo-tetrahydrodicyclopentadiene (exo-THDCPD) through the isomerization of endo-tetrahydrodicyclopentadiene (endo-THDCPD) was investigated over HY zeolite catalysts. Conversion of endo-THDCPD increased with the increase of $Si/Al_2$ ratio of HY zeolite catalysts, which can be attributed to increase of acid strength with increase of $Si/Al_2$ ratio. Yield of exo-THDCPD, however, was the highest over HY with $Si/Al_2$ ratio of 30, because the production of cyclopentadiene and oligomers was minimized. The optimal reaction temperature was $180^{\circ}C$ because the higher reaction temperature increased the production of by-products. The yield of exo-THDCPD also increased with the amount of the catalyst in feed. In the isomerization reaction of endo-THDCPD using the HY zeolite catalysts, it was confirmed that the internal diffusion resistance in the pore of catalysts would have more significant effects on the reaction activity than that of the external diffusion resistance of catalysts.

Studies on the Cell Immobilization of Alkalophilic Streptomyces sp. B-2 for the Glucose Isomerization (포도당 이성화를 위한 Alkalophilic Streptomyces sp. B-2의 균체 고정화에 관한 연구)

  • 이은숙
    • The Korean Journal of Food And Nutrition
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    • v.11 no.3
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    • pp.319-322
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    • 1998
  • The whole cell of alkalophilic Streptomyces sp. B-2 which produce glucose isomerase was immobilized by entrapment method for the effective production of high fructose syrup. The highest immobilized activity was achieved when the enzyme was bound to 2% $textsc{k}$-carrageenan. Immobilized glucose isomerase the pH optimum was about pH 7.5~8.5. Immobilization of alkalophilic Streptomyces sp. B-2 on 2% $textsc{k}$-carrageenan at 7$0^{\circ}C$ showed an increase in glucose isomerase activity. GI activity of immobilized cells was maximum Co2+ concentration 10-3M, Mg2+ concentration 10-3M.

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Studies on the Glucose Isomerizing Enzyme -Part I. The Isolation and Detection of Glucose Isomerizing Enzyme produced by Microorganism- (포도당(葡萄糖) 이성화(異性化) 효소(酵素)에 관(關)한 연구(硏究) -제1보(第一報), 포도당(葡萄糖) 이성화(異性化) 효소생성균(酵素生成菌)의 분리(分離) 및 검색(檢索)-)

  • Seu, J.H.;Kim, C.K.;Ki, W.K.;Rhee, I.K.;Kwon, T.J.;Woo, D.L.
    • Applied Biological Chemistry
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    • v.11
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    • pp.43-47
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    • 1969
  • With an attempt to obtain a glucose isomerizing enzyme producing microorganism, one hundred and thirty-three strains of microorganism were isolated from soil samples. After screening, a strain K-17 which belonging to actinomyces family, was finally selected. Using this strain of K-17, sugars produced from glucose by the reaction of sugar isomerizing enzyme were tested with paper chromatography. Only a kind of resulting sugar, fructose, was detected from enzyme reaction sample and other sugars were never detected. By these results, the enzyme produced by strain K-17 is classified as a glucose isomerase.

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Preparation of $TiO_2$ Particles using Binary Ionic Liquids for Photocatalysis (이성분계 이온성액체를 이용한 광촉매용 이산화 티타늄 입자 제조)

  • Lee, Seulbi;Yoo, Kye Sang
    • Applied Chemistry for Engineering
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    • v.23 no.4
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    • pp.405-408
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    • 2012
  • $TiO_2$ particles with various shapes were synthesized by using a modified sol-gel method with binary ionic liquids. The structural properties of the particles were significantly affected by the composition of ionic liquids. This is mainly attributed to the interaction between the organic solvent and ionic liquid at the interface leading to the formation of particle structure. The photocatalytic activity of the prepared samples was also examined for the degradation of 4-chlorophenol. Among the particles, $TiO_2$ prepared with 1-octyl-3-methylimidazolium tetrafluoroborate and 1-octyl-3-methylimidazolium tetrafluoroborate showed the best photocatalytic performance.