• Title/Summary/Keyword: Kinetic mechanism

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An Emerging New Paradigm of the Control Mechanism of Cellular Functions

  • Park, Chun-Sik
    • Proceedings of the Korean Biophysical Society Conference
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    • 1999.06a
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    • pp.14-15
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    • 1999
  • The control mechanism of cellular functions has been classified into two modes: one rapid mechanism occurring within minutes by kinetic alterations of effector proteins without changing the number of effector molecules and another slow mechanism occurring over hours and days by changes in the number of effector molecules without kinetic alterations.(omitted)

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Kinetic Mechanism in the Absence of Metal of Hafnia alvei Aspartase in the Amination Direction

  • Ra, Im Jeong;Kim, Hyo Jun;Yun, Mun Yeong
    • Bulletin of the Korean Chemical Society
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    • v.22 no.3
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    • pp.288-292
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    • 2001
  • The kinetic mechanism of Hafnia alvei aspartase in the amination direction has been determined in the absence of metal. The initial velocity pattern obtained by varying the concentration of fumarate at several fixed concentrations of NH4+ , shows an intersection on the left of the ordinate at pH 7.0, indicating that the kinetic mechanism is a sequential mechanism in which substrate inhibition by fumarate is observed. The dead-end inhibition pattern by varying the concentration of NH4+ at several fixed concentration of succinate shows an intersection on the left of the ordinate. These data are consistent with random addition of NH4+, or fumarate. The Haldane relationship gives a Keq of 1.18 ${\times}$10-3 M at pH 7.0, which is in agreement with the values obtained from the direct determination of reaction concentrations at equilibrium (6.0 $\pm0.2$ ${\times}$10-3 M).

A Short Kinetic Mechanism for Premixed Flames of Aromatic Compound : Benzene (방향족 화합물 화염의 축소 반응 메카니즘 개발 : 벤젠)

  • Lee, Ki Yong
    • 한국연소학회:학술대회논문집
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    • 2015.12a
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    • pp.161-164
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    • 2015
  • A short kinetic mechanism for premixed benzene/air flames was developed with a reduction method of Simulation Error Minimization Connectivity Method(SEM-CM). It consisted of 38 species and 336 elementary reactions. Flame speeds were calculated and compared with those from full mechanisms and experiments of other researcher. Those comparisons are in good agreement between the full mechanism and the short mechanism at high pressure condition. In numerical work the running time with the short mechanism was over 10 times faster than one with the full mechanism.

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Spray Coating Technology (스프레이 코팅 기술)

  • Lee, Chang-Hee
    • Journal of ILASS-Korea
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    • v.13 no.4
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    • pp.193-199
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    • 2008
  • Spray coating is a versatile surface modification technology in which coating is built-up based on the successive deposition of micron-scaled particles. Depending on the coating materials, the coatings can meet the required mechanical properties, corrosion resistance, and other properties of base materials. Spraying processes are mainly classified into thermal and kinetic spraying according to their bonding mechanism and deposition characteristics. Specifically, thermal spraying process can be further classified into many categories based on the design and mechanism of the process, such as frame spraying, arc spraying, atmospheric plasma spraying (APS), and high velocity oxygen-fuel (HVOF) spraying, etc. Kinetic spraying or cold gas dynamic spraying is a newly emerging coating technique which is low-temperature and high-pressure coating process. In this paper, overall view of thermal and kinetic spray coating technologies is discussed in terms of fundamentals and industrial applications. The technological characteristics and bonding mechanism of each process are introduced. Deposition behavior and properties of technologically remarkable materials are reviewed. Furthermore, industrial applications of spray coating technology and its potentials are prospected.

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Reduced Chemical Kinetic Mechanism for Premixed CO/H2/Air Flames ([ CO/H2/Air ] 예혼합 화염에 대한 준총괄 화학반응 메커니즘)

  • Jang, Kyoung;Cha, Dong-Jin;Joo, Yong-Jin;Lee, Ki-Yong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.2
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    • pp.133-140
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    • 2008
  • A reduced chemical kinetic mechanism is developed in order to predict the flame phenomena in premixed $CO/H_2/Air$ flames at atmospheric pressure, aimed at studying the coal gas combustion for the IGCC applications. The reduced mechanism is systematically derived from a full chemical kinetic mechanism involving 11 reacting species and 66 elementary reactions. This mechanism consists of four global steps, and is capable of explicitly calculating the concentration of 7 non-steady species and implicitly predicting the concentration of 3 steady state species. The fuel blend contains two fuels with distinct thermochemical properties, whose contribution to the radical pool in the flame is different. The flame speeds predicted by the reduced mechanism are in good agreement with those by the full mechanism and experimental results. In addition, the concentration profiles of species and temperature are also in good agreement with those by the full mechanism.

Treatment of nitrobenzene-cotaminated Wastewater using Oxidation Reaction (산화제를 이용한 니트로벤젠 함유 폐수 처리)

  • 신진환;손종렬
    • Journal of environmental and Sanitary engineering
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    • v.17 no.1
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    • pp.69-74
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    • 2002
  • This study explored for treatment processes by investigating the treatment efficiency and reaction mechanism through oxidation reaction using UV and $O_3$ as oxidant in compensate the wastewater containing nitrobenzene that is non biodegradable organic. Also by modeling these reactions, we try to step explanation of optimum reaction rate and reaction mechanism as the development of the computer program predictable the reaction rate by modeling the reaction. By using this model, after kinetic constant for each reaction from an experimental data is made an optimization and for hardly contribute to reaction rate in reaction kinetic equation is made an ignorance and suppose the simplified reaction mechanism, examined the propriety of computer simulation model and simplified reaction mechanism by comparing and inspecting the reaction kinetic constant and masstransfer coefficient. An investigation results for destructional treatment of nitrobenzene in the wastewater as non-biddegradable organic using UV, $O_3{\;}O_2{\;}H_2O_2-UV$ as oxidant.

A Kinetic Study of Biphenyl Type Epoxy-Xylok Resin System with Different Kinds of Catalysts

  • 한승;김환근;윤호규;문탁진
    • Bulletin of the Korean Chemical Society
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    • v.18 no.11
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    • pp.1199-1203
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    • 1997
  • The investigation of cure kinetics of biphenyl epoxy (4,4-diglycidyloxy-3,3,5,5-tetramethyl biphenyl)-xylok resin system with four different catalysts was performed by differential scanning calorimeter using an isothermal approach. All kinetic parameters of the curing reaction including the reaction order, activation energy and rate constant were calculated and reported. The results indicate that the curing reaction of the formulations using triphenylphosphine (TPP) and 1-benzyl-2-methylimidazole (1B2MI) as a catalyst proceeds through a first order kinetic mechanism, whereas that of the formulations using diazabicyloundecene (DBU) and tetraphenyl phosphonium tetraphenyl borate (TPP-TPB) proceeds by an autocatalytic kinetic mechanism. To describe the cure reaction in the latter stage, we have used the semiempirical relationship proposed by Chern and Poehlein. By combining an nth order kinetic model or an autocatalytic model with a diffusion factor, it is possible to predict the cure kinetics of each catalytic system over the whole range of conversion.

A Short Kinetic Mechanism for Premixed Flames of Aromatic Compound : Benzene (방향족 화합물 화염의 축소 반응 메카니즘 개발 : 벤젠)

  • Lee, Ki Yong
    • Journal of the Korean Society of Combustion
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    • v.20 no.4
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    • pp.49-55
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    • 2015
  • A short kinetic mechanism for premixed benzene/air flames was developed with a reduction method of Simulation Error Minimization Connectivity Method(SEM-CM). It consisted of 38 species and 336 elementary reactions. Flame speeds were calculated and compared with those from full mechanisms and experiments of other researchers. Flame temperature, the heat release rate, the concentration profiles of major species and radicals were also calculated with both mechanism. Those comparisons are in good agreement between the full mechanism and the short mechanism at high pressure condition. In numerical work the running time with the short mechanism was over 12 times faster than one with the full mechanism.

A Study on a Configuration of the Load Characteristic Evaluation Device Using Hydraulic Power for the Analysis of the Tilting Kinetic Mechanism (틸팅 부하메커니즘 특성 분석을 위한 유압식 부하특성 평가 장치구성에 대한 연구)

  • Lee, Jun-Ho;Kim, Ho-Yeon;Han, Seong-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.12
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    • pp.1152-1158
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    • 2011
  • In this paper a configuration of the load evaluation device for the tilting actuator using hydraulic power is presented, which makes it possible to measure the force action on the tilting actuator. It is possible to measure only current using the conventional electro-mechanical actuator when the bogie is in the process of the tilting. This makes impossible to measure the force acting on the tilting actuator. In order to overcome this problem a kinetic mechanism test system using hydraulic cylinder is proposed. The system are consisted of hydraulic cylinder for the tilting actuation, control system to control hydraulic power, sensors to measure for force and displacement and monitoring system for the user interface.