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Molecular dynamics with the stochastic process provides a convenient way to compute structural and thermodynamic properties of chemical, biological, and materials systems. It is demonstrated that the virtual dynamics case that we proposed for the Langevin equation[J. Chem. Phys. 147 , 184104 (2017)] in principle exists in other types of stochastic thermostats as well. The recommended "middle" scheme[J. Chem. Phys. 147 , 034109 (2017)] of the Andersen thermostat is investigated as an example. As shown by both analytic and numerical results, while the real and virtual dynamics cases approach the same plateau of the characteristic correlation time in the high collision frequency limit, the accuracy and efficiency of sampling are relatively insensitive to the value of the collision frequency in a broad range. After we compare the behaviors of the Andersen thermostat to those of Langevin dynamics, a heuristic schematic representation is proposed for understanding efficient stochastic thermostatting processes with molecular dynamics. 相似文献
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The non-cutoff Boltzmann equation can be simulated using the DSMC method, by a truncation of the collision term. However,
even for computing stationary solutions this may be very time consuming, in particular in situations far from equilibrium.
By adding an appropriate diffusion, to the DSMC-method, the rate of convergence when the truncation is removed, may be greatly
improved. We illustrate the technique on a toy model, the Kac equation, as well as on the full Boltzmann equation in a special
case. 相似文献
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A hyperbolic Stefan problem based on the linearized Gurtin—Pipkin heat conduction law is considered. The temperature and
free boundary are controlled by a thermostat acting on the boundary. This feedback control is based on temperature measurements
performed by real thermal sensors located within the domain containing the two-phase system and/or at its boundary. Three
different types of thermostats are analyzed: simple switch, relay switch, and a Preisach hysteresis operator. The resulting
models lead to integrodifferential hyperbolic Stefan problems with nonlinear and nonlocal boundary conditions. Existence results
are proved in all the cases. Uniqueness is also shown, except in the situation corresponding to the ideal switch.
Accepted 27 May 1997 相似文献
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Molecular dynamics with the stochastic process provides a convenient way to compute structural and thermodynamic properties of chemical, biological, and materials systems. It is demonstrated that the virtual dynamics case that we proposed for the Langevin equation[J. Chem. Phys. 147, 184104 (2017)] in principle exists in other types of stochastic thermostats as well. The recommended "middle" scheme[J. Chem. Phys. 147, 034109 (2017)] of the Andersen thermostat is investigated as an example. As shown by both analytic and numerical results, while the real and virtual dynamics cases approach the same plateau of the characteristic correlation time in the high collision frequency limit, the accuracy and efficiency of sampling are relatively insensitive to the value of the collision frequency in a broad range. After we compare the behaviors of the Andersen thermostat to those of Langevin dynamics, a heuristic schematic representation is proposed for understanding efficient stochastic thermostatting processes with molecular dynamics. 相似文献
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Deterministic dynamics in extended phase space of a constant temperature interacting spin system is formulated. The spin temperature is recovered through the constrained equation of motion and is in agreement with Rugh’s geometrical approach to temperature for classical Heisenberg spin systems. Detailed comparisons are investigated between state-of-the-art stochastic spin dynamics and deterministic dynamics using a chain of thermostats, for which an accelerated convergence structure is found. 相似文献
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根据VXQ-150A荧光光谱仪测量单元恒温装置原理,对美国LECO公司生产的红外、热导气体分析仪器检测箱内恒温装置进行了国产化的改造。 相似文献
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