耗散系统不可逆过程中的可拓展广义相对论时空关系

在引入非保守非惯性系的基础上对不可逆过程建立非保守系等效性假设，在引入广域度规的基础上对具有复杂行为的时空建立非保守系协变性假设；利用密度分布的不均匀度h(ρ)和粗粒熵S（ρtε）及推导的多标度因数η*计算式，引入非保守惯性质量和非保守引力质量.分析表明，新结果使引力理论与非平衡态统计理论和非线性动力学达到应有的谐和，发展并修正广义相对论. 关键词： 时空关系 耗散系统 不可逆性 可拓展广义相对论 非保守引力质量     

Reformulation of the support set selection problem in the logical analysis of data

The paper is concerned with the problem of binary classification of data records, given an already classified training set of records. Among the various approaches to the problem, the methodology of the logical analysis of data (LAD) is considered. Such approach is based on discrete mathematics, with special emphasis on Boolean functions. With respect to the standard LAD procedure, enhancements based on probability considerations are presented. In particular, the problem of the selection of the optimal support set is formulated as a weighted set covering problem. Testable statistical hypothesis are used. Accuracy of the modified LAD procedure is compared to that of the standard LAD procedure on datasets of the UCI repository. Encouraging results are obtained and discussed.     

Thermokinetic Studies of the Process for Electrorefining Silver

In this work some calorimetric measurements were also carried out on the electrorefining silver by using different current densities with a Calvet type microcalorimeter at room temperature. The ratio (R) of the measured heat (

A nonequilibrium entropy for dynamical systems

It is proposed to define entropy for nonequilibrium ensembles using a method of coarse graining which partitions phase space into sets which typically have zero measure. These are chosen by considering the totality of future possibilities for observation on the system. It is shown that this entropy is necessarily a nondecreasing function of the timet. There is no contradiction with the reversibility of the laws of motion because this method of coarse graining is asymmetric under time reversal. Under suitable conditions (which are stated explicitly) this entropy approaches the equilibrium entropy ast+ and the fine-grained entropy ast–. In particular, the conditions can always be satisfied if the system is aK-system, as in the Sinai billiard models. Some theorems are given which give information about whether it is possible to generate the partition used here for coarse graining from time translates of a finite partition, and at the same time elucidate the connection between our concept of entropy and the entropy invariant of Kolmogorov and Sinai.Research supported in part by NSF grants PHY78-03816 and PHY78-15920.     

Hidden Dissipation and Irreversibility in Maxwell’s Demon

Maxwell’s demon is an entity in a 150-year-old thought experiment that paradoxically appears to violate the second law of thermodynamics by reducing entropy without doing work. It has increasingly practical implications as advances in nanomachinery produce devices that push the thermodynamic limits imposed by the second law. A well-known explanation claiming that information erasure restores second law compliance fails to resolve the paradox because it assumes the second law a priori, and does not predict irreversibility. Instead, a purely mechanical resolution that does not require information theory is presented. The transport fluxes of mass, momentum, and energy involved in the demon’s operation are analyzed and show that they imply “hidden” external work and dissipation. Computing the dissipation leads to a new lower bound on entropy production by the demon. It is strictly positive in all nontrivial cases, providing a more stringent limit than the second law and implying intrinsic thermodynamic irreversibility. The thermodynamic irreversibility is linked with mechanical irreversibility resulting from the spatial asymmetry of the demon’s speed selection criteria, indicating one mechanism by which macroscopic irreversibility may emerge from microscopic dynamics.     

不可逆费米奥托制冷循环性能分析

基于回热式不可逆奥托制冷循环和理想费米气体的状态方程,导出以费米气体为工质的奥托制冷循环的输入功、制冷量、制冷系数等重要性能参数的表达式,以此讨论费米气体的量子简并性、回热及内不可逆性对循环性能的影响,给出以理想费米气体为工质的回热式不可逆奥托制冷循环的性能特征。所得结果有助于进一步了解经典气体奥托制冷循环与量子气体奥托制冷循环的区别和联系。     

铁性体中畴结构产生的热力学描述

在批判平衡态热力学局限性的基础上,采用不可逆过程热力学对铁性体中畴结构的产生做了动态描述.注意到了铁电与铁磁两种情况下的相似与区别.在铁弹情况下,出于客观的必要性,类比地引入了铁弹相变“分子场”的概念.明确了体系的有限性、过程的不可逆性与畴结构的产生的内在关联. 关键词： 铁性体 畴结构 不可逆性 对称性     

孤立系内热传导过程(火积)耗散的解析解

(火积)耗散与熵增均可以作为传热不可逆性的度量, 当前(火积)理论的反对者认为(火积)是不必要的. 为说明(火积)的必要性, 从有效性的角度进行了论证, 即在描述传热过程不可逆性的变化上, (火积)的严格解析解存在, 而熵的严格解析解难以得到. 本文构建了孤立系内的一维及多维热传导模型, 求解了温度及其梯度的级数型解析解, 将其代入(火积)耗散的求解式, 得到其最初的形式为一多重级数的多重积分, 交换积分与级数计算顺序, 并利用特征函数的正交性, 将(火积)耗散求解式中的积分运算求出, 并使级数的维数降低, 最终将其表示为一稳态项与一瞬态项加和的形式, 其极限与文献中的结果一致. 通过对孤立系内(火积)耗散解析解的求解可以得出: 由于热传导过程熵与(火积)的解析解求解难度不同, 在描述传热过程不可逆性变化上, (火积)更加有效; 对于孤立系内不同维数的热传导问题, 只要温度场解析解存在, (火积)耗散解析解均可以应用特征函数正交性求解得到.     

Entropy and irreversibility in a dilute gas of hard disks

The partition of the canonical entropy (invariant of motion) into a thermodynamic part 5th and a nonthermodynamic oneS _nonth, respectively increasing and decreasing functions of time for a system approaching equilibrium, was proposed by Prigogine and co-workers. This viewpoint is critically examined in the special case of an initially uncorrelated gas of hard disks. BothSth and the leading term ofS _nonth are evaluated for finite assemblies of 400,1600, and 6400 disks, by the method of molecular dynamics. There is good evidence that, in the limit of an infinite system, the Prigogine scheme is verified.On leave of absence from the University of Brussels, Belgium.