玻尔兹曼常数测定实验测量范围研究

在0℃-70℃内不同温度条件下多次试验，研究在不同温度条件下测量范围的规律，建立了测量范围的经验公式，提出了在不同温度条件下测量范围的选择方法，     

保守力场中理想气体分子按势能分布的讨论

从统计力学角度出发,应用巨配分函数表示的理想气体分子数密度和动能表示式,采用分部积分和对比方法,证明了玻尔兹曼今布律完全符合统计力学中的麦克斯韦-玻尔兹曼统计法,并进一步说明了玻尔兹曼分布律与各种保守力场中的理想气体分子存在的空间维数和遵从何种能谱无关。     

熵增意味着能量的贬值

从热力学与统计物理学的观点说明：系统熵的增大就意味着能量可利用程度的减小,或者说伴随着熵增的是能量的贬值。     

Boltzmann方程的量子修正

讨论了经典玻尔兹曼分布函数的量子修正项及其满足的方程。我们将用于推导量子玻尔兹曼方程的梯度近似中的普朗克常数明显地写出，并且将量子Wigner分布函数用普朗克常数展开，经过推导就可以得到量子修正项所满足的方程。量子Wigner分布函数的普朗克常数展开式中的一阶和高阶项正好是量子修正项，它们可具有负值，而零阶项则具有正值。这样我们自然在量子Wigner分布函数中分离出正的分布函数，避免了用Husimi方法做粗粒平均取得正值的传统框架。另外我们也用量子Wigner分布函数普朗克常数展开的方法讨论了量子热力学熵的经典极限这一问题。     

利用晶体管测定玻尔兹曼常数

玻尔兹曼常数是玻尔兹曼统计理论以及近代物理学微观领域中的一个十分重要的常数。对它的深入了解有助于理工科学生在微观物理图像与宏观物理问题之间建立更清晰的概念和现代物理思想,有非常重要的实际意义。     

受限玻尔兹曼机的步态特征提取及其识别

针对步态识别问题,研究了受限玻尔兹曼机的步态特征提取及其识别.主要基于行人图像序列,通过背景分割、归一化以及步态周期的计算,采用叠加方法生成步态能量图,以此作为步态的特征图像,利用受限玻尔兹曼机自动获取步态特征.选取中科院CASIA步态数据库以及支持向量机、孪生支持向量机、神经网络与K-近邻方法对使用受限玻尔兹曼机方法的特征提取进行了研究,同时与主成分分析PCA、线性判别分析LDA、卷积神经网络CNN特征提取与识别方法进行了比较.     

度量的艺术

正物理学在于观察,通过测量予以量化,以单位进行表达。处理物理单位的做法不断演变,与科学家对物理学本身越来越深入的理解有关。目前全球的科学家使用国际单位制。人们很容易认可国际单位制的正确性,而定义和建立一致又实用的单位制是一桩繁重的差事,目前这一维持和发展度量标准的工作主要由全国性度量衡学研究机构完成。度量衡学研究受益于物理学发展的同时,也在推动基     

Lattice Boltzmann method and its applications in engineering thermophysics

The lattice Boltzmann method （LBM）, a mesoscopic method between the molecular dynamics method and the conventional numerical methods, has been developed into a very efficient numerical alternative in the past two decades. Unlike conventional numerical methods, the kinetic theory based LBM simulates fluid flows by tracking the evolution of the particle distribution function, and then accumulates the distribution to obtain macroscopic averaged properties. In this article we review some work on LBM applications in engineering thermophysics： （1） brief introduction to the development of the LBM; （2） fundamental theory of LBM including the Boltzmann equation, Maxwell distribution function, Boltzmann-BGK equation, and the lattice Boltzmann-BGK equation; （3） lattice Boltzmann models for compressible flows and non-equilibrium gas flows, bounce back-specular-reflection boundary scheme for microscale gaseous flows, the mass modified outlet boundary scheme for fully developed flows, and an implicit-explicit finite-difference-based LBM; and （4） applications of the LBM to oscillating flow, compressible flow, porous media flow, non-equilibrium flow, and gas resonant oscillating flow.     

给水管网非恒定流动数值计算方法

为计算给水管网中非恒定流动运行工况,使系统可以快速平稳地完成工况转换,以非恒定流动理论为基础,分别利用重分阻尼系数法划分时间步长的特征线法和引入摩阻附加项的玻尔兹曼网格法计算给水管网非恒定流动的数学模型,并应用于某小区给水管网的非恒定流动工况分析中.结果表明,在管网非恒定流工况下,当Re≤7 000时利用玻尔兹曼网格法计算,否则利用特征线法计算将提高计算的准确性和计算效率.     

Simulation of phase transition process using lattice Boltzmann method

A new lattice Boltzmann model based on SC model, is proposed to describe the liquid-vapor phase transitions. The new model is validated through the simulation of the one-component phase transition process. Compared with the simulation results of van der Waals gas and the Maxwell equal-area construction, the results of the new model have a better agreement with the analytical solutions than those of SC and Zhang models. Since the obtained temperature range and the maximum density ratio in this model are expanded, and the magnitude of maximum spurious current is only between those of SC and Zhang models, it is believed that this new model has better stability than SC and Zhang models. Consequently, the application scope of this new model is expanded compared with the existing phase transition models. According to the principle of the corresponding states in engineering thermodynamics, the simulations of ammonia and water phase transition process were implemented using this new model with different equations of state. Compared with the experimental data of ammonia and water, the results show that the Peng-Robinson is the best equation of state to describe the phase transition process of ammonia and water. Especially, the simulation results of ammonia with Peng-Robinson equation of state have an excellent agreement with its experimental data. Therefore these simulation results have a significant influence on the real engineering applications.