共查询到20条相似文献,搜索用时 31 毫秒
1.
Aoiz FJ Bañares L Castillo JF Brouard M Denzer W Vallance C Honvault P Launay JM Dobbyn AJ Knowles PJ 《Physical review letters》2001,86(9):1729-1732
Rigorous quantum dynamical calculations have been performed on the ground 1 1A' and first excited 1 1A" electronic states of the title reaction, employing the most accurate potential energy surfaces available. Product rovibrational quantum state populations and rotational angular momentum alignment parameters are reported, and are compared with new experimental, and quasiclassical trajectory calculated results. The quantum calculations agree quantitatively with experiment, and reveal unequivocally that the 1 1A" excited state participates in the reaction. 相似文献
2.
We prepare metastable glassy states in a model glass former made of Lennard-Jones particles by sampling biased ensembles of trajectories with low dynamical activity. These trajectories form an inactive dynamical phase whose "fast" vibrational degrees of freedom are maintained at thermal equilibrium by contact with a heat bath, while the "slow" structural degrees of freedom are located in deep valleys of the energy landscape. We examine the relaxation to equilibrium and the vibrational properties of these metastable states. The glassy states we prepare by our trajectory sampling method are very stable to thermal fluctuations and also more mechanically rigid than low-temperature equilibrated configurations. 相似文献
3.
Richard Kraaij Alexandre Lazarescu Christian Maes Mark Peletier 《Journal of statistical physics》2018,170(3):492-508
Much of the structure of macroscopic evolution equations for relaxation to equilibrium can be derived from symmetries in the dynamical fluctuations around the most typical trajectory. For example, detailed balance as expressed in terms of the Lagrangian for the path-space action leads to gradient zero-cost flow. We expose a new such fluctuation symmetry that implies GENERIC, an extension of gradient flow where a Hamiltonian part is added to the dissipative term in such a way as to retain the free energy as Lyapunov function. 相似文献
4.
The problem of elastomechanical equilibrium for a static, spherically symmetric star composed of an elastic material is analyzed. A suitable formulation of relativistic elasticity theory is used, and the second order equilibrium equations are found. It is shown that the equilibrium conditions with anisotropic pressure introducedad hoc by some authors are in fact the dynamical conditions for a relativistic elastic material. The corresponding first order equations for the components of the metric and of the energy-momentum tensor reduce to the Tolman-Oppenheimer-Volkhoff equations if the material exhibits no shape-rigidity. Two interesting classes of solutions are discussed. 相似文献
5.
It is shown that a slender elastic fiber moving in a Stokesian fluid can be susceptible to a buckling instability--termed the "stretch-coil" instability--when moving in the neighborhood of a hyperbolic stagnation point of the flow. When the stagnation point is part of an extended cellular flow, it is found that immersed fibers can move as random walkers across time-independent closed-streamline flow. It is also found that the flow is segregated into transport regions around hyperbolic stagnation points and their manifolds, and closed entrapment regions around elliptic points. 相似文献
6.
Petrova N. V. Yakovkin I. N. Ptushinskii Yu G. 《The European Physical Journal B - Condensed Matter and Complex Systems》2004,38(3):525-531
Kinetics of low-temperature hydrogen and deuterium adsorption on W(110) and Mo(110) surfaces have been studied by the real-time Monte Carlo simulations. Recently reported qualitative dependence of the adsorption characteristics on variation of the H2 flux is described in terms of the dynamical equilibrium between incident and desorption fluxes and improved conditions for accommodation for the hydrogen molecules at high incident fluxes. The role of the intrinsic precursor state in hydrogen dissociative adsorption is analyzed.Received: 16 February 2004, Published online: 28 May 2004PACS:
82.65. + r Surface and interface chemistry; heterogeneous catalysis at surfaces - 02.50.Ng Distribution theory and Monte Carlo studies - 82.20.Wt Computational modeling; simulation 相似文献
7.
Wilson F. N. Santos 《Brazilian Journal of Physics》2012,42(5-6):373-390
This work deals with a computational investigation on the small ballistic reentry Brazilian vehicle SAtélite de Reentrada Atmosférica (SARA). Hypersonic flows over the vehicle SARA at zero-degree angle of attack in chemical equilibrium and thermal nonequilibrium are modeled by the direct simulation Monte Carlo method, which has become the main technique for studying complex multidimensional rarefied flows, and which properly accounts for the nonequilibrium aspects of the flows. The emphasis of this paper is to examine the behavior of the primary properties during the high-altitude portion of SARA reentry. In this way, velocity, density, pressure, and temperature field are investigated for altitudes of 100, 95, 90, 85, and 80?km. In addition, comparisons based on geometry are made between axisymmetric and planar two-dimensional configurations. Some significant differences between these configurations were noted on the flowfield structure in the reentry trajectory. The analysis showed that the flow disturbances have different influence on velocity, density, pressure, and temperature along the stagnation streamline ahead of the capsule nose. It was found that the stagnation region is a thermally stressed zone. It was also found that the stagnation region is a zone of strong compression, high wall pressure. Wall pressure distributions are compared with those of available experimental data, and good agreement is found along the spherical nose for the altitude range investigated. 相似文献
8.
Alberto Frigerio 《Letters in Mathematical Physics》1977,2(2):79-87
For a quantum dynamical semigroup possessing a faithful normal stationary state, some conditions are discussed, which ensure the uniqueness of the equilibrium state and/or the approach to equilibrium for arbitrary initial condition.A fellowship from the Italian Ministry of Public Education is acknowledged. 相似文献
9.
Emil Bureau Frank Schilder Michael Elmegård Ilmar F. Santos Jon J. Thomsen Jens Starke 《Journal of sound and vibration》2014
We propose and investigate three different methods for assessing stability of dynamical equilibrium states during experimental bifurcation analysis, using a control-based continuation method. The idea is to modify or turn off the control at an equilibrium state and study the resulting behavior. As a proof of concept the three methods are successfully implemented and tested for a harmonically forced impact oscillator with a hardening spring nonlinearity, and controlled by electromagnetic actuators. We show that under certain conditions it is possible to quantify the instability in terms of finite-time Lyapunov exponents. As a special case we study an isolated branch in the bifurcation diagram brought into existence by a 1:3 subharmonic resonance. On this isola it is only possible to determine stability using one of the three methods, which is due to the fact that only this method guarantees that the equilibrium state can be restored after measuring stability. 相似文献
10.
Dynamical evolution processes of traffic flow and travel cost in urban transportation networks
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Considering such a fact that travellers dynamically adjust their routes and the resultant link traffic flows in a network evolve over time, this paper proposes a dynamical evolutionary model of the traffic assignment problem with endogenous origin-destination (OD) demands. The model's stability is analysed and the resultant user equilibrium (UE) state is shown to be stable under certain conditions. Numerical results in a grid network indicate that the model can generate convergent flow patterns and finally terminates at the UE state. Impacts by the parameters associated with OD demand function and link cost function are also investigated. 相似文献
11.
We consider situations where, in a continuous-time dynamical system, a nonchaotic attractor coexists with a nonattracting chaotic saddle, as in a periodic window. Under the influence of noise, chaos can arise. We investigate the fundamental dynamical mechanism responsible for the transition and obtain a general scaling law for the largest Lyapunov exponent. A striking finding is that the topology of the flow is fundamentally disturbed after the onset of noisy chaos, and we point out that such a disturbance is due to changes in the number of unstable eigendirections along a continuous trajectory under the influence of noise. 相似文献
12.
13.
This paper investigates the dynamical behaviour of network traffic
flow. Assume that trip rates may be influenced by the level of
service on the network and travellers are willing to take a faster
route. A discrete dynamical model for the day-to-day adjustment
process of route choice is presented. The model is then applied to a
simple network for analysing the day-to-day behaviours of network
flow. It finds that equilibrium is arrived if network flow consists
of travellers not very sensitive to the differences of travel cost.
Oscillations and chaos of network traffic flow are also found when
travellers are sensitive to the travel cost and travel demand in a
simple network. 相似文献
14.
15.
Herbert Spohn 《Letters in Mathematical Physics》1977,2(1):33-38
We give an algebraic condition in order that a completely positive dynamical semigroup of an N-level system has a unique (invariant) equilibrium state and that every initial state approaches this equilibrium state as t
. We apply our result to a semigroup arising in the weak coupling limit. 相似文献
16.
R. Bessenrodt 《Zeitschrift für Physik A Hadrons and Nuclei》1970,235(2):110-123
Starting from Onsager's assumption that the dynamical equilibrium correlations can be separated into a microscopic and a hydrodynamic part it is shown how to obtain phenomenological state variables in non-equilibrium, regression fluctuation theorems and (in some important cases) microscopic representations of thermal transport coefficients. The results are demonstrated for “pure” heat conduction, but most of them can be easily extended to systems which are described initially by the densities of dynamical constants. 相似文献
17.
O. de Pazzis 《Communications in Mathematical Physics》1973,29(2):113-130
The dynamical theory of a bidimensional model of hard squares with elastic collisions is presented. The time evolution is shown to exist on a large class of infinite configurations. Moreover, it is proved that any equilibrium state, that is any solution of the equilibrium equations, is concentrated on this set of allowed initial configurations and is invariant under the time evolution. 相似文献
18.
本文提出了一种新的混沌时间序列高维相空间多元图重心轨迹动力学特征提取方法. 在确定了最佳嵌入维数和延迟时间后, 将相空间中高维矢量点映射到二维平面的雷达图上, 相应地将相空间中高维矢量点变换为对应的几何多边形. 通过提取几何多边形的重心位置得到重心轨迹动力学演化特性, 并利用重心轨迹矩特征量区分不同性质的混沌时间序列. 在此基础上, 处理分析了气液两相流电导传感器动态信号, 发现高维相空间多元图重心轨迹矩特征量不仅可以辨识泡状流、段塞流和混状流, 而且为流型动力学演化机理提供了新的分析途径. 相似文献
20.
C. Boldrighini 《Communications in Mathematical Physics》1986,103(3):499-514
We consider a one-dimensional system of particles on the half line =[0, ] interacting through elastic collisions among themselves and with a wall at the origin. On the first particle a constant forceE is acting, no external forces act on the other particles. All particles are identical except the first one which has a larger mass. We prove that ifE is such that the Gibbs equilibrium state exists, the corresponding equilibrium dynamical system is a Bernoulli flow.On leave from Dipartimento di Matematica e Fisica, Università di Camerino, Camerino, Italy. Partially supported by NSF Grant DMR-81-14726 相似文献