• Title/Summary/Keyword: Transition state

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Transition State Characterization of the Low- to Physiological-Temperature Nondenaturational Conformational Change in Bovine Adenosine Deaminase by Slow Scan Rate Differential Scanning Calorimetry

  • Bodnar, Melissa A.;Britt, B. Mark
    • BMB Reports
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    • v.39 no.2
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    • pp.167-170
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    • 2006
  • Bovine adenosine deaminase undergoes a nondenaturational conformational change at $29^{\circ}C$ upon heating which is characterized by a large increase in heat capacity. We have determined the transition state thermodynamics of the conformational change using a novel application of differential scanning calorimetry (DSC) which employs very slow scan rates. DSC scans at the conventional, and arbitrary, scan rate of $1^{\circ}C/min$ show no evidence of the transition. Scan rates from 0.030 to $0.20^{\circ}C/min$ reveal the transition indicating it is under kinetic control. The transition temperature $T_t$ and the transition temperature interval ${\Delta}T$ increase with scan rate. A first order rate constant $k_1$ is calculated at each $T_t$ from $k_1\;=\;r_{scan}/{\Delta}T$, where $r_{scan}$ is the scan rate, and an Arrhenius plot is constructed. Standard transition state analysis reveals an activation free energy ${\Delta}G^{\neq}$ of 88.1 kJ/mole and suggests that the conformational change has an unfolding quality that appears to be on the direct path to the physiological-temperature conformer.

The Rheological Behaviors of Solid-Liquid Transfer Emulsion (고상-액상 전이형 에멀젼의 레올로지 거동)

  • Park, Byeong-Gyun;Han, Jong-Sub;Lee, Sang-Min;Lee, Cheon-Koo;Yoon, Moung-Seok
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.31 no.2 s.51
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    • pp.135-140
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    • 2005
  • A solid state emulsion haying high velocity gradient shows two important transition ranges in the plot of storage modulus(G') as a function of shear strain, when the state is changed from solid to liquid. However, a solid state emulsion having low velocity gradient shows only one apparent transition range when the change from solid to liquid state takes place. The result implies the importance of the surface properties in the solid state emulsion. The addition of water phase in the solid state emulsion reduces the modulus in the modulus in the surface transition range by increasing interfacial friction and weakening the matrix. The addition of pigments increases the modulus in the modulus in the surface transition range by reinforcing the matrix, when there is no wafer phase in the solid state emulsion. When the solid state emulsion has water phase, however, the addition of pigments decreases the modulus in the modulus in the surface transition range.

Performance Analysis of Tradeoff between Energy Consumption and Activation Delay in UMTS State Transition Mechanism (UMTS 상태 천이 방식에서 에너지 소비와 활성 지연간의 트레이드오프 성능 분석)

  • Choi, Hyun-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37A no.12
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    • pp.1085-1092
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    • 2012
  • Mobile communication systems define user state transition mechanisms in order to manage radio resources and battery power efficiently. In the state transition mechanism, a state with a higher energy consumption inherently offers a shorter access delay, so there is a tradeoff between the energy and delay performances. In this paper, we analyze the user state transition mechanism of UMTS by considering the bursty traffic attributes of mobile applications. We perform a numerical evaluation for both the energy consumption and the activation delay by Markov modeling of the state transition mechanism, and investigate their tradeoff relationship as functions of operational parameters. The resulting energy-delay tradeoff curves clearly show an achievable performance bound of the user state transition mechanism and also offer an optimal operation strategy to minimize the energy consumption while guaranteeing the delay requirement.

Transition-State Structures for Solvolysis of Methanesulfonyl Chloride

  • 양기열;강금덕;구인선;이익준
    • Bulletin of the Korean Chemical Society
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    • v.18 no.11
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    • pp.1186-1191
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    • 1997
  • Solvolyses of methanesulfonyl chloride (CH3SO2Cl) in water and methanol have been studied theoretically using ab initio self-consistent reaction field (SCRF) molecular orbital method. All stationary structures including transition state on the potential energy surface in solution have been found and compared with the gas phase structures. The overall reaction occurs via a concerted SN2 mechanism with a non-cyclic trigonal bipyramidal transition state, and the activation barrier is lowered significantly in solution. The transition state for the hydrolysis reaction is looser than that for the methanolysis reaction, and this is in accord with the experimental findings that an SN2 type mechanism, which is shifted toward an SN1 process or an SAN process in the hydrolysis and alcoholysis reaction, respectively, takes place. The catalytic role of additional solvent molecules appears to be a purely general-base catalysis based on the linear transition structures. Experimental barrier can be estimated by taking into account the desolvation energy of nucleophile in the reaction of methanesulfonyl chloride with bulk solvent cluster as a nucleophile.

A Low Power Algorithm using State Transition Ready Method (상태 전환 준비 방법을 이용한 저전력 알고리즘)

  • Youn, Choong-Mo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.9 no.9
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    • pp.971-976
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    • 2014
  • In this paper, we proposed a low power algorithm using state transition ready method. The proposed algorithm defined a sleep state, a idle state and a run state for the task. A state transition occurring at the time due to the delay time created in order to reduce the power consumption state in the middle of each inserted into the ready state. The ready state considering a power consumption and a delay time in state transition. A scheduling step of performing the steps in excess of the increasing problems have the delay time is long. The power consumption increased for the operation step increase. A state transition from a sleep state with the longest delay time in operating state occurs when the state is switched by the time delay caused by the increase in operating time reduces the overall power consumption reduced. Experiments [6] were compared with the results of the power consumption. The experimental results [6] is reduced power consumption than the efficiency of the algorithm has been demonstrated.

Theoretical Studies of the Low-Lying Electronic States of Diazirine and 3,$3^{\prime} $-Dimenthyldiazirine

  • 한민수;조한국;정병서
    • Bulletin of the Korean Chemical Society
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    • v.20 no.11
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    • pp.1281-1287
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    • 1999
  • The low-lying electronic states of diazirine and 3,3'-dimethyldiazirine have been studied by high level ab initio quantum chemical methods. The equilibrium geometries of the ground state and the first excited singlet and triplet states have been optimized using the Hartree-Fock (HF) and complete active space SCF (CASSCF) methods, as well as using the Møller-Plesset second order perturbation (MP2) theory and the single configuration interaction (CIS) theory. It was found that the first excited singlet state is of 1 B1 symmetry resulting from the n- π* transition, while the first excited triplet state is of 3 B2 symmetry resulting from the π- π* transition. The harmonic vibrational frequencies have been calculated at the optimized geometry of each electronic state, and the scaled frequencies have been compared with the experimental frequencies available. The adiabatic and vertical transition energies from the ground electronic state to the low-lying electronic states have been estimated by means of multireference methods based on the CASSCF wavefunctions, i.e., the multiconfigurational quasidegenerate second order perturbation (MCQDPT2) theory and the CASSCF second-order configuration interaction (CASSCF-SOCI) theory. The vertical transition energies have also been calculated by the CIS method for comparison. The computed transition energies, particularly by MCQDPT2, agree well with the experimental observations, and the electronic structures of the molecules have been discussed, particularly in light of the controversy over the existence of the so-called second electronic state.

Small signal stability analysis of power systems with non-continuous operating elements by using RCF method : Modeling of the state transition equation (불연속 동작특성을 갖는 전력계통의 RCF법을 사용한 미소신호 안정도 해석 : 상태천이 방정식으로의 모델링)

  • Kim Deok Young
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.342-344
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    • 2004
  • In conventional small signal stability analysis, system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of state matrix. However, when a system contains switching elements such as FACTS devices, it becomes non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is by means of eigenvalue analysis of the system periodic transition matrix based on discrete system analysis method. In this research, RCF(Resistive Companion Form) method is used to analyse small signal stability of a non-continuous system including switching elements'. Applying the RCF method to the differential and integral equations of power system, generator, controllers and FACTS devices including switching elements should be modeled in the form of state transition matrix. From this state transition matrix eigenvalues which are mapped to unit circle can be calculated.

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