逆极限的不变测度和一致正熵性质

In this paper, the interconnection of some ergodic properties between a continuous selfmap and its inverse limit is studied. It has been proved that (1) their invariant Borel probability measures are identical up to homeomorphism and (2) they preserve uniform positive entropy property simuitaneously. As applications, it is also proved that the upper semi-continu-ous properties of their entropy maps are restricted each other, and the entropy map of the asymptotically h-expansive continuous map is upper semi-contlnuous, at the same time a continuous map having u, p.e. is topological weakmixing.     

The Semiclassical Limit in the Quantum Drift-Diffusion Equations with Isentropic Pressure

The semiclassical limit in the transient quantum drift-diffusion equations with isentropic pressure in one space dimension is rigorously proved. The equations are supplemented with homogeneous Neumann boundary conditions. It is shown that the semiclassical limit of this solution solves the classical drift-diffusion model. In the meanwhile, the global existence of weak solutions is proved.     

基于PSO和模糊划分熵的水下图像分割

在水下环境中,由于存在着水体对光线的吸收以及照明不均等原因,水下图像具有信噪比低、边缘模糊等特点。如果直接使用传统的分割方法,对水下图像进行处理后的效果较差。传统的基于最大熵原理的阈值法尽管能实现某些特定的分割任务,但是其时效性较差。而粒子群算法(PSO)是一类随机全局优化技术,该算法简单易实现,可调参数少。因此将群体智能中的粒子群优化算法应用到图像分割中。新方法在重新定义模糊熵的基础上,根据最大熵原理,利用粒子群算法来搜索分割阈值。相对于传统的利用穷举法来搜索分割阈值的算法,新方法大大减少了计算时间,提高了效率。通过对水下图像处理实验证明,该算法对简单背景的图像分割是有效的,和传统分割方法相比,具有更强的自适应性和抗噪性能。     

自由活塞激波风洞压缩管非等熵流动分析

在自由活塞驱动的高超声速地面试验设备中,自由活塞压缩器的运行状态对于试验气流状态参数、试验时间及设备安全性起到决定性的作用.研究基于FD?21自由活塞激波风洞结构参数,针对典型的活塞压缩器运行状态展开数值模拟和等熵理论预测,分析压缩管中的波系结构和非等熵效应引起的流动参数变化.进一步地,将压缩管中的总熵变来源分解为激波...     

单原子粒子体系标准摩尔熵和标准摩尔焓的计算

根据统计热力学原理,对单原子粒子体系(固体化合物中阳离子体系和气态阳离子体系)的标准摩尔熵和标准摩尔焓的计算公式进行理论推导,并根据文献中的实验数据进行计算机拟合,得到定量数学模型。通过模型检验,计算值与实验值非常吻合,说明此模型很好地揭示了影响单原子体系标准摩尔熵和标准摩尔焓的微观本质因素。     

橡胶弹热制冷效应的热力学分析与教学设计

橡胶分子链独有的柔顺性和熵弹性特征,使其表现出巨大形变能力和明显的弹热效应。近年来基于橡胶回缩-吸热机理的弹热制冷现象逐渐受到重视,从而为高分子物理学的研究开辟了一个新的方向。本文在“高分子物理学”课程高弹形变和弹热效应的热力学分析基础上,引入橡胶弹热制冷效应的原理与研究进展,设计“基于橡胶熵弹性的弹热制冷效应”的教学目标、教学过程等内容,不仅有助于将抽象的高分子物理学基础理论转化为实际应用范例,提升“高分子物理学”课程的学习质量,还锻炼了大学生跟踪学科前沿、开展创新训练的意识与能力。     

Quantum entanglement in the mode-mode competition system

Considering a two-level atom interacting with the competing two-mode field, this paper investigates the entanglement between the two-level atom and the two-mode field by using the quantum reduced entropy, and that between the two-mode field by using the quantum relative entropy of entanglement. It shows that the two kinds of entanglement are dependent on the relative coupling strength of atom-field and the atomic distribution, and exhibit the periodical evolution. The maximal atom-field entanglement state can be prepared via the appropriate selection of system parameters and interaction time.     

Analytic solutions for degenerate Raman-coupled model

The Raman-coupled interaction between an atom and a single mode of a cavity field is studied. For the cases in which a light field is initially in a coherent state and in a thermal state separately, we have derived the analytic expressions for the time evolutions of atomic population difference W, modulus B of the Bloch vector, and entropy E. We find that the time evolutions of these quantities are periodic with a period of π. The maxima of W and B appear at the scaled interaction time points τ- = kπ（k = 0, 1, 2,...）. At these time points, E = 0, which shows that the atom and the field are not entangled. Between these time points, E ≠ 0, which means that the atom and the field are entangled. When the field is initially in a coherent state, near the maxima, the envelope of W is a Gaussian function with a variance of 1/（4n^-）（n^- is the mean number of photons）. Under the envelope, W oscillates at a frequency of n^-/π. When the field is initially in a thermal state, near the maxima, W is a Lorentz function with a width of 1/n^-.     

<新概念物理教程·热学>改革的思路

结合《新概念物理教程．热学》的编写，阐述了热学教学改革的主要思路。