• 대한화학회지
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• 제17권1호
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• pp.25-30
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• 1973

$\gamma$,$\gamma$,$\gamma$-Trichloroethylidene-m-Nitroacetophenone과 phenylhydrazine및 치환된 phenylhydrazine들과의 반응으로 2,6-disubstituted-3-pyridazinone들을 합성하였으며 2,4-dinitrophenylhydrazine과의 반응에서는 hydrazone을 중간체로 분리하였다. hydrazinehydrate와의 반응에서는 3-(mnitrophenyl)-5-trichloromethyl-2-pyrazoline이 좋은 수득률로 얻어졌다. 또한$\gamma$,$\gamma$,$\gamma$-trichloroethylidene-m-nitroacetophenone과 치환된 phenylhydrazine과의 반응에서 phenyl기에 결합된 치환기의 효과를 검토하였다.

• Journal of Radiation Protection and Research
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• 제26권3호
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• pp.287-290
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• 2001

The 9.17MeV gamma-rays from the $^{13}C(p,\;{\gamma})^{14}N,\;^{14}N({\gamma},\;{\gamma})^{14}N$ reactions were measured. The incident 9.17MeV gamma-ray was produced from the $^{13}C(p,\;{\gamma})^{14}N$ reaction at Ep=1.75MeV resonance. The 1.75MeV proton beam was accelerated using the 3MV SNU-AMS Tandetron and 1.7MV KIGAM Tandem accelerators. The enriched 13C target was $121{\mu}g/cm^2$ self-supporting foil, and we used liquid nitrogen as a resonant absorption target. We used a HP-Ge detector with 30% efficiency and less 2keV energy resolution. We developed new method to detect the scattered 9.17MeV gamma-ray from the nitrogen target by using the energy difference between the Doppler shifted gamma-ray from the $^{13}C(p,\;{\gamma})^{14}N$ reaction and the resonant absorbed and rescattered gamma-ray from the $^{14}N({\gamma},\;{\gamma})^{14}N$ reaction.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1679-1684
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• 2011

Interfacial reactions kinetics often differ from kinetics of bulk reactions. Here, we describe how the density change of an immobilized reactant influences the kinetics of interfacial reactions. Self-assembled monolayers (SAMs) of alkanethiolates on gold were used as a model interface and the Diels-Alder reaction between immobilized quinones and soluble cyclopentadiene was used as a model reaction. The kinetic behavior was studied using varying concentrations of quinones. An unusual threshold density of quinones (${\Gamma}_c$ = 5.2-7.2%), at which the pseudo-first order rate constant started to vary as the reaction progressed, was observed. This unexpected kinetic behavior was attributed to the phase-separation phenomena of multi-component SAMs. Additional experiments using more phase-separated two-component SAMs supported this explanation by revealing a significant decrease in ${\Gamma}_c$ values. When the background hydroxyl group was replaced with carboxylic or phosphoric acid groups, ${\Gamma}_c$ was observed at below 1%. Also, more phase-separated thermodynamically controlled SAMs produced a lower critical density (3% < ${\Gamma}_c$ < 4.9%) than that of the less phaseseparated kinetically controlled SAMs (6.5% < ${\Gamma}_c$ < 8.9%).

• 폴리머
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• 제24권2호
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• pp.168-173
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• 2000

자유 라디칼 개시제인 2,2'-azobisisobutyronitrile (AIBN)을 사용하여 1,4-dioxane 용매하에서 N-isopropylacrylamide (NIPAAM)와 methyl methacrylate (MMA)를 공중합하였다. 온도에 따른 NIPAAM과 MMA의 반응성비를 알아보기 위해 각각 50, 60, 7$0^{\circ}C$에서 중합하여 전환율이 10 wt%이하가 되도록 반응을 정지시켰다. 단량체 반응성비는 Finemann-Ross법으로 구하였으며, 그 값은 5$0^{\circ}C$에서는 ${\gamma}$$_2$=0.259, ${\gamma}$$_2$=2.782, 6$0^{\circ}C$에서는 ${\gamma}$$_1$=0.271, ${\gamma}$$^2$=0.819, 그리고 7$0^{\circ}C$에서는 ${\gamma}$$_1$=0.286, ${\gamma}$$_2$=2.915로 나타나, 반응온도가 높아질수록 ${\gamma}$$_1$, ${\gamma}$$_2$ 값이 증가함을 알 수 있었다. 또한 반응온도와 반응성비와의 관계로부터 활성화에너지의 차를 구할 수 있었으며, 그 결과 반응성비는 온도 의존성이 있는 것으로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제21권12호
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• pp.1233-1238
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• 2000

$Mo/{\gamma}-Al_2O_3catalysts$ modified with Fe, Co, and Ni were prepared by impregnation method and catalytic activity for water gas shift reaction was examined. The optimum amount of Mo loaded for the reaction was 10 wt% $MoO_3$ to ${\gamma}-Al_2O_3.$ The catalytic activity of $MoO_3/{\gamma}-Al_2O_3was$ increased by modifying with Fe, Co, and Ni in the order of Co${\thickapprox}$ Ni > Fe. The optimum amounts of Co and Ni added were 3 wt% based on CoO and NiO to 10 wt% $MoO_3/{\gamma}-Al_2O_3$, restectively. The TPR (temperature-programmed reduction) analysis revealed that the addition of Co and Ni enganced the reducibility of the catalysts. The results of both catalytic activity and TPR experiments strongly suggest that the redox property of the catalyst is an important factor in water gas shift reaction on the sulfided Mo catalysts, which could be an evidence of oxy-sulfide redox mechanism.

• Journal of Radiation Protection and Research
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• 제35권2호
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• pp.85-90
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• 2010

본 연구에서는, 에너지에 따른 peak의 상대효율을 구하였으며, 검출기의 응답함수를 작성하였다. 이를 위해 고효율, 고분해능을 가진 HPGe 검출기(지름 78.7 mm, 길이 86.5 mm)를 이용하였으며 콤프턴 억제용으로 NaI 검출기를 사용하였다. 감마선 스펙트럼은 $^{23}Na$(p, $\gamma$)$^{24}Mg$ 및 $^{27}Al$(p, $\gamma$)$^{28}Si$ 반응을 이용하여 얻었으며, 이 때 입사 입자의 에너지는 각각 $E_p$ = 1424 keV 및 $E_p$ = 992 keV 이었다. 한편 스펙트럼 측정은 입사 빔 방향에 대해 $55^{\circ}$에서 하였으며, 사용한 가속기는 일본 동경공업대학의 3 MeV Pelletron 가속기를 이용하였다. 검출기의 응답함수는 1.2 MeV에서 9.4 MeV까지 0.75 MeV 간격으로 작성하였다.

• 대한화학회지
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• 제12권2호
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• pp.55-60
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• 1968

芳香族誘道體 化合物의 鹽素化反應을 紫外線照射 및 ${\gamma}$-線照射下에서 行하였던 바 ethyl,${\alpha} ,{\beta} -dichloro-{\beta}$-phenyl propionate의 境遇 紫外線下에서는 主로 p-chloro 化合物이 生成되었다. 같은 反應을 ${\gamma}$-線 照射下에서 行한 結果 에스텔과 鹽素의 몰比가 1:2일 때에는 p-chloro 化合物이 主로 生成되었으나 몰比가 1:8인 境遇에는 側鎖鹽素化物이라고 判斷되는 多鹽素化合物이 生成되었다. 反應生成物을 確認하기 爲하여서 ethyl , ${\alpha} ,{\beta} -dichloro-{\beta}$-(p-chlorophenyl) propionate 및 ethyl${\alpha} ,{\beta} -dichloro-{\beta}$ -($o$-chlorophenyl) propionate 를 各各 ${\gamma}$-線 照射下에서 鹽素化시켜 보았더니 p-chloro誘道體에서는 側鎖鹽素化物을, o-chloro誘道體에서는 o,p-dichlorophenyl 化合物에 各各 該當하는 鹽素化物을 生成하였다. 化合物 確認에는 放射化 thin layer chromatography를 利用 하였으며 鹽素含量을 放射化分析法을 分析하였다. 反應結果를 鹽素化反應에 對한 芳香族의 置換基의 效果와 關聯시켜 論議하였으며 實驗方法을 記述하였다.

• Journal of Microbiology and Biotechnology
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• 제6권4호
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• pp.238-244
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• 1996

$\gamma$-Glutamyl transpeptidase ($\gamma$-GTP; EC 2.3.2.2) present in the culture filtrate of Bacillus sp. KUN-17 was purified 400-fold through a consecutive procedure including organic precipitation and column chromatography. The enzyme has an estimated molecular weight of 70, 000 and consists of hetero-subunits with molecular weights of 42, 000 and 22, 000. In vitro optimal conditions for those transfer and hydrolysis reactions appeared to be pH 7.0 at $50^{\circ}C$ and pH 8.4 at $40^{\circ}C$, respectively. The denatured enzyme recovered most of its $\gamma$-GTP activity by removing detergents such as sodium dodecyl sulfate (SDS) or urea with dialysis. The enzyme showed higher affinities against a number of amino acids as $\gamma$-glutamyl acceptors than glycylglycine in the following order: L-valine, L-methionine, L-glutamic acid or L-as-paragine, L-alanine. Also, it was shown that L-glutamine was the most suitable $\gamma$-glutamyl donor for the transfer reaction among those tested. Amino acids generally inhibited the enzyme activity for the transfer reaction, but not for the hydrolysis reaction.

• Applied Biological Chemistry
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• 제40권6호
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• pp.478-483
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• 1997

E. coli K-12 균주에서 ${\gamma}-Glutamylcysteine$ synthetase를 정제하고 효소적 방법에 의한 글루타치온 합성에 관련된 특성을 검사하였다. 정제한 효소의 활성은 L-glutamate의 농도가 60 mM 까지 증가와 더불어 증가하였으나, 60 mM L-cysteine 에서는 50% 그리고 45 mM glycine 에서는 40%의 효소활성이 감소되었다. 효소의 활성은 반응산물 중의 하나인 ADP 뿐만 아니라 환원형 글루타치온에 의해서 감소되었다. 그러므로 환원형 글루타치온 뿐만 아니라 glutathione synthetase의 기질인 glycine은 ${\gamma}-glutamylcysteine$ synthetase 활성을 저해하므로 글루타치온 생산을 위해서는 ${\gamma}-glutamylcysteine$ synthetase 반응과 glutathione synthetase의 두 분리된 반응으로 이루어진 생반응계를 고안하는 것이 바람직하다. 또한 글루타치온 합성반응으로 부터 생성되는 ADP는 ${\gamma}-glutamylcysteine$ synthetase의 활성을 감소시키므로 글루타치온 합성을 위해서 ATP 재생계의 도입이 필요하다.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.229-240
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• 2002

Quantum mechanical calculation is performed for the $O(^1D)$ + HCl ${\rightarrow}$OH + Cl reaction using Reactive Infinite Order Sudden Approximation. Shifting approximation is also employed for the l ${\neq}$ 0 partial wave contributions. Various dynamical quantities are calculated and compared with available experimental results and quasiclassical trajectory results. Vibrational distributions agree well with experimental results i.e. product states mostly populated at $v_f$ = 3, 4. Our results also show small peak at $v_f$ = 0, which indicates bimodal vibrational distribution. The results show two significant broad peaks in ${\gamma}_i$ dependence of the cross section, one is at ${\gamma}_i$ = $15^{\circ}-35^{\circ}$ and the another is at ${\gamma}_i$= $55^{\circ}-75^{\circ}$ which can be explained as steric effects. At smaller gi, the distribution is peaked only at higher state ($v_f$ = 3, 4) while at the larger gi, both lower state ($v_f$ = 0) and higher state ($v_f$ = 3, 4) are significantly populated. Such two competing contributions (smaller and larger ${\gamma}_i$) result in the bimodal distribution. From these points we suggest two mechanisms underlying in current reaction system: one is that reaction occurs in a direct way, while the another is that reaction occurs in a indirect way.