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971.
The properties of fluctuations in space in or outside thermal equilibrium are obtained by solving hierarchies of equations derived either from the Liouville or the Master equation. In particular we study the one-, two-, etc., time correlation functions that describe the spatial and temporal behavior of the fluctuations in space. Explicit solutions are obtained for a dilute gas. The Langevin approach is briefly discussed. Our results are compared with those obtained in the extensive literature, which is reviewed in some detail. 相似文献
972.
N. G. van Kampen 《Journal of statistical physics》1981,25(3):431-442
In the presence of internal noise the variables describing a system are intrinsically stochastic. If they constitute a Markov process the expansion enables one to extract a deterministic macroscopic equation and to compute the fluctuations in successive approximations. In the lowest or linear noise approximation the fluctuations can be represented by a Langevin equation, provided it is handled appropriately. Higher orders cannot be described by any white noise Langevin equation. The question whether the equation has to be interpreted according to Itô or Stratonovich concerns these higher orders, for which the equation is not valid anyway. 相似文献
973.
974.
SHEN Yu-Feng WANG Qing-Hai ZHU Dao-Qian ZHOU Liang-Mo Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning China 《中国化学》1994,12(2):129-137
The study on retention behavior in supercritical fluid chromatography (SFC) is necessary to understand the mechanism of the various interactions in SFC. The retention of SFC in carboxylic acid methyl ester/polymethylsiloxane/CO2 system was studied systematically and the retention behavior of this kind of compounds under various typical operation conditions was described using the method of an alternative unified theory of chromatographic retention. The results illustrated that expression: Ink.= a + b/T + cp + dp/T + ep2/T can be used to describe quantitatively the retention behavior of carboxylic acid methyl ester/polymethylsiloxane/CO2 system in the ranges of reduced density from 0.549 to 1.411. It was also found that the entropy of solute in stationary phase is dependent on the density of supercritical fluid (SF) under typical operating conditions of SFC. 相似文献
975.
Yoshisuke Ueda 《Journal of statistical physics》1979,20(2):181-196
This paper deals with turbulent or chaotic phenomena which occur in the system governed by Duffing's equation, a special type of two-dimensional periodic system. By using analog and digital computers, experiments are carried out with special reference to the change of attractors and of average power spectra of the random processes under the variation of the system parameters. On the basis of the experimental results, an outline of the random process is made clear. The results obtained in this paper will be applied to various physical problems and will also serve as material for the development of a proper mathematics of this phenomenon. 相似文献
976.
A boundS
l is given for the number of bound statesn
i in thelth partial wave corresponding to a spherically symmetric potential in non-relativistic quantum mechanics. This bound is given
by
whereV
a(l, r) is the attractive part of the effective potentialV(r)+l(l+1)/r
2. Extensive comparative study ofS
i and the Bargmann inequality is made. 相似文献
977.
为考察微极流体的热流体动力润滑特性,根据微极流体的基本理论和能量守恒与转换定律,推导了微极流体的能量方程;依据其润滑条件假设,得出了润滑条件下微极流体的能量方程的简化形式.以有限长滑动轴承为例,将所推导的能量方程与微极流体的雷诺方程和轴瓦热传导方程联立进行数值求解,得到油膜及轴瓦的温度分布.结果表明:采用微极性流体润滑,其油膜及轴瓦的温度均比采用牛顿流体有所升高,流体的微极性越强,温度升高越明显. 相似文献
978.
Lotka-Volterra方程的全局指数稳定性 总被引:2,自引:0,他引:2
曾永福 《四川大学学报(自然科学版)》2005,42(1):38-40
研究一类具有时滞的Lotka-Volterra生物方程,证明该系统在一定条件下存在正的平衡态,并给出了正平衡态指数稳定的充分条件。 相似文献
979.
利用扩展的双曲函数法的基本思想,求得了一维非线性传输线电位方程的孤立子解和其它具有奇异性的类孤立子解,并对此孤立子解和具有奇异性的类孤立子解的物理意义进行了讨论。 相似文献
980.
原华丽 《山东师范大学学报(自然科学版)》2005,20(2):14-15
给出了线性Sobolev方程初边值问题的半离散H^1-Galerkin混合有限元格式,通过误差分析,得到了未知函数的L^2模和梯度函数的散度空间模的最优阶误差估计。 相似文献