• Title/Summary/Keyword: reactions

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New Nuclear Fusion for Our Second Generations

  • Ho-Jin Choi;Koan-Sik Joo
    • Proceedings of the Safety Management and Science Conference
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    • 1999.11a
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    • pp.421-424
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    • 1999
  • In this short report (before the authors would like to introduce an important application for one of the techniques of complex angular momentunm, say, Regge Pole approach, to nuclear fusion reaction for Light-ions: it will be reported in forthcoming papers), two kinds of thermalnuclear fusion reaction sources are introduced and discussed (A) the case of fusion: the production of neutron and target of Deuteron and (B) the case of fusion: the production of proton and target of Deuteron. Nuclear fusion reactions for Light-ions , such as the thermalnuclear energy sources and fuel cycles, are already well known. Fusion reactions are widely known as being extremly important and nationally vital (in point of view of nuclear weapons we must reconsider seriously development and building of such dangerous weapons) for our next generations in the future. This paper (a topics in review) is concerned with a simple introduction about a new nuclear fusion reaction of the above case of (B) for the second generation. Typical thermalnuclear fusion reactions which result in the release of huge amount of energy are nuclear stripping reactions:

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Analysis of Oxidation-reduction Equilibria in Aqueous Solution Through Frost Diagram (Frost도를 이용한 수용액의 산화-환원반응 평형 해석)

  • Lee, Man Seung
    • Resources Recycling
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    • v.26 no.4
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    • pp.3-8
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    • 2017
  • Oxidation-reduction reaction is one of the most important reactions occurring in the aqueous phase. Analysis of the equilibria related to these oxidation-reduction reactions is of great value in designing many unit operations in hydrometallurgy, such as leaching, separation and electrochemical reactions. The construction of Frost diagram was discussed in this work. The conditions at which disproportionation and proportionation reactions can occur were explained by analyzing Frost diagram together with Latimer table. The information which can be obtained from Frost diagram was discussed.

Evaluation of a Radical Mechanistic Probe for NADH-dependent Horse Liver Alcohol Dehydrogenase Reactions by Computer Graphics Modeling

  • Chung Sung Kee;Chodosh Daniel F.
    • Bulletin of the Korean Chemical Society
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    • v.9 no.1
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    • pp.44-48
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    • 1988
  • The feasibility of the reduction of nortricyclanone (1) as a chemical probe for testing the proposed radical mechanism for NAD-dependent horse liver alcohol dehydrogenase (HLADH) reactions has been examined using computer graphics modeling. The resutls of this study suggest that the radical ring-opening of this probe molecule may involve too substantial a geometry reorganization for the molecule to serve as a chemical probe in detecting the possible presence of the radical intermediates in the HLADH reactions. This result suggests that one should exercise caution in extrapolating results obtained from chemically based radical probes in the solution phase to the topologically constrained systems such as enzyme-substrate reactions.

Study of the Kinetics and Mechanisms of Alkoxy Radical Reactions in the Gas Phase (I). Arrhenius Parameters for t-Butoxy Radical Reactions with Isobutane and Cyclohexane

  • Song, Se-Ahn;Choo, Kwang-Yul
    • Bulletin of the Korean Chemical Society
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    • v.5 no.1
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    • pp.16-21
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    • 1984
  • The relative Arrhenius parameters for t-butoxy radical decomposition (log $A_d$, $E_d$) and hydrogen abstraction of t-butoxy radical from hydrogen donor (log $A_d$, $E_d$) by competitive method were obtained as follows: for cyclohexane; log $A_a/A_d$ = -4.17 mole/l and $E_d-E_a$ = 9.01 kcal/mole, for isobutane; log $A_a/A_d$ = -5.70 mole/l and $E_e-E_a$= 11.0 kcal/mole. From the reported Arrhenius parameters for t-Butoxy radical decomposition reactions the parameters for t-Butoxy radical reactions with isobutane and cyclohexane are estimated to be log $A(l/mol{\cdot}sec)$ = 8.4, $E_a$ = 4.3 kcal/mol and $log A (l/mol{\cdot}sec)= 9.9,\;E_a$ = 6.3 kcal/mol, respectively.

Theoretical Studies on Gas-Phase Reactions of Negative Ions with Alkyl Nitrites

  • Park, Hyeong Yeon;Kim, Chan Gyeong;Lee, Bon Su;Lee, Hae Hwang;Lee, Ik Chun
    • Bulletin of the Korean Chemical Society
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    • v.21 no.8
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    • pp.823-827
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    • 2000
  • Gas-Phase reactions of methyl and ethyl nitrites with anionic nucleophiles of SH-, F- and OH- are investigated theoretically at the MP2/6-311+G* level. The SN2 processes are all highly exothermic and proceed with a typ-icaI double-weIl reaction coordinate profile. The elimination reactions of methyl nitrite with SH- and F- are double-well energy surface processes,with stabilizedproduct complexes of NO-...H2S and NO-...HF, pro-ceeding by an E1 cb-like E2 mechanism. The $\beta-elimination$ of ethyl nitrite is an E2 type process. The $\alpha-elimi-nation$ reactions of methyl and ethyl nitrites with OH- have triple-well energy profiles of Elcb pathway with an $\alpha-carbanion$ intermediate which is stabilized bythe vicinal $nc\alpha-{\sigma}*o-N$ charge transfer interactions. CompIex-ation ofmethyl carbanion with HF seems to provide a stable intermediate within a triple-well energy profile of El cb channel in the reaction of F- with methyl nitrite.

Cross Interaction Constants As a Measure of the Transition State Structure (Part VI). Nucleophilic Substitution Reactions of Benzyl Chlorides with Anilines and Benzylamines

  • Lee, Ik-Choon;Huh, Chul;Koh, Han-Joong;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • v.9 no.6
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    • pp.376-378
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    • 1988
  • Results of kinetic studies on the reactions of benzyl chlorides with anilines and benzylamines are reported. Analyses of the cross interaction constants relevant to the degree of bond formation, ${\rho}_{XY}$ and ${\lambda}_{XY}$, are carried out. The magnitudes of the two parameters indicated that the degree of bond formation in the transition state is the typical of that expected for an $S_N2$ reaction, but the reactions with benzylamines appear to have a slightly less degree of bond formation compared with the reactions with anilines.

Nucleophilic Substitution Reactions of Thiopheneethyl Arenesulfonates with Anilines and N,N-Dimethylanilines

  • 오혁근;윤정환;조인호;이익준
    • Bulletin of the Korean Chemical Society
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    • v.18 no.4
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    • pp.390-394
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    • 1997
  • Nucleophilic substitution reactions of 2-thiopheneethyl benzenesulfonates (2-TEB) and 3-thiopheneethyl benzenesulfonates (3-TEB) with anilines and N,N-dimethylanilines (DMA) are investigated in acetonitrile at 60.0 ℃. The cross-interaction constants ρxz determined for the reactions with anilines are large negative (- 0.50) which are comparable to those for the similar predominantly frontside-attack SN2 reactions of 1-phenylethyl (1-PEB), 2-phenylethyl (2-PEB) and cumyl benzenesulfonates. A large negative ρxz value (- 0.4∼- 0.8) is considered to provide a mechanistic criterion for the frontside-attack SN2 mechanism with a four-center transition state. In agreement with this proposal the kinetic isotope effects, kH/kD, involving deuterated aniline nucleophiles are all greater than one reflecting partial N-H(D) bond cleavage in the transition state. The MO theoretical reactant structures of 1-PEB, 2-PEB and 2-TEB based on the PM3 calculation show that the benzene ring blocks the backside nucleophile approach to the reaction center carbon (Cα) enforcing the frontside-attack SN2 mechanism.

N-Substitution Reactions of 1-Substituted Tetrazoline-5-thiones

  • Kang, Han-Young;Cho, Yong-Seo;Lee, Won-Jae;Koh, Hun-Yeong;Chang, Moon-Ho
    • Bulletin of the Korean Chemical Society
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    • v.11 no.6
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    • pp.543-546
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    • 1990
  • N- vs. S-Substitution reactions of 1-substituted tetrazoline-5-thiones with various allyl or benzyl halides were studied in order to find effective conditions for N-substitution reactions. When allyl or benzyl halides were reacted with 1-substituted tetrazoline-5-thiones in the presence of TMSI or $BF_3{\cdot}OEt_2$ (or other Lewis acids), N-substitution at 4-position in addition to S-substitution occurred. Reactions were performed either with or without a solvent such as dioxane or propionitrile in the presence of potassium iodide.

Theoretical study of the Reactions of $H+H_2$ and Its Isotopic Variants Inter- and Intramolecular Isotope effect

  • 성주범
    • Bulletin of the Korean Chemical Society
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    • v.19 no.6
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    • pp.634-641
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    • 1998
  • Quasiclassical trajectory calculations were carried out for the reactions of $H+H_2$ (V=O, J=O) and its isotope variants on the Siegbahn-Liu-Truhlar-Horowitz potential energy surface for the relative energies E between 6 and 150 kcal/mol. The goal of the work was to understand the inter- and intramolecular isotope effects. We examine the relative motion of reactants during the collision using the method of analysis that monitors the intermolecular properties (internuclear distances, geometry of reactants, and final product). As in other works, we find that the heavier the incoming atom is, the greater the reaction cross section is at the same collision energy. Using the method of analysis we prove that the intermolecular isotope effect is contributed mainly by differences in reorientation due to the different reduced masses. We show that above E=30 kcal/mol recrossing also contributes to the intermolecular isotope effect. For the intramolecular isotope effect in the reactions of H+HD and T+HD, we reach the same conclusions as in the systems of $O(^3P)+HD$, F+HD, and Cl+HD. That is, the intramolecular isotope effect below E=150 kcal/mol is contributed by reorientation, recrossing, and knockout type reactions.

Allergic reactions to local anesthetic mepivacaine in dental procedures: a case report

  • Yoonhyoung Nam;Seyeon Min;Wonse Park;Kee-Deog Kim
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.23 no.3
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    • pp.173-177
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    • 2023
  • Local anesthetics are an essential part of pain control during dental treatment. Despite its effectiveness and safety, patients should constantly be aware of potential adverse effects, including allergic reactions. Allergic reactions to amide-type local anesthetics (LAs), such as lidocaine and mepivacaine, are rare compared to those to ester-type LAs. Herein, we report the case of a patient with a history of allergy to lidocaine and mepivacaine, with symptoms of itching, diffuse erythema of the wrists and hands, dizziness, and pectoralgia. This case report emphasizes the importance of collecting medical and dental histories of patients is necessary, and how an allergy test in the allergy and clinical immunology department helps select safe LAs for patients.