液体粘滞系数的准确测量和计算

指出了粘滞系数实验中的计算错误，详细推导了正确计算液体粘滞系数的计算公式。     

一种测量液体粘滞系数的新方法

文章报道了一种测量液体粘滞系数的新方法－微机控制超声多普勒法,它将超声技术与计算机技术相结合,利用超声多普勒效应接收液体中下落小球的频移信号,将此信号送微机进行采集、比较、判断、计算并出粘滞系数,应用本方法能快速准确地测量多种液体的粘滞系数。     

多维Kramers公式的研究

本文研究了鞍点附近多维的位能曲面及鞍点所在位置;并用Werner Wheeler及无旋液体等两种方法计算了多维的质量系数与粘滞系数,然后用多维Kramers公式计算了裂变速率.发现裂变速率随着维数的增加而适当增大.不同的形变参量以及不同的计算质量和粘滞系数方法对计算核裂变速率影响不大.从结果看,采用三维计算裂变几率已足够准确.     

液体粘滞系数与温度关系实验及曲线拟合

本文介绍一种可以调节温度,且恒温较好的落球法测量液体粘滞系数的装置,用此装置可以较精确地测量不同温度时液体的粘滞系数值。由实验测量得出的粘滞系数与温度的关系,将通过三种基本函数回归分析,计算出衡量各回归曲线回归程度好坏的标准差,从而判定哪一函数最适合液体粘滞系数随温度变化的实际规律。本文还用离散的实验数据点代入N次多项式,用最小二乘法确定其系数,从而求得待测液体粘滞系数与温度关系的曲线方程.此例提供了一种如何用统计手段确定待测数据特性的方法。     

Ar-N2混合气体输运性质的量子力学研究

基于物理力学理论,利用量子力学的IOSA方法、Numerov相移计算法和Ar-N₂相互作用的等效势模型计算了Ar在N₂气体中的扩散系数的粘滞系数,计算值与实验值符合较好,比Giantur-co等人(GVD)计算便更接近实验值,特别是粘滞系数,在整个计算区域内基本和实验相同。     

用布里渊散射测量水的体粘滞系数

提出了一种直接测量水的体粘滞系数的实验方法－布里渊散射方法,通过分析剪切粘滞系数和体粘滞系数与布里渊散射线宽的关系,得到了布里渊散射线宽和频移与水的体粘滞系数关系的公式,建立了实验测量水的体粘滞系数的基础,给出了不同温度下水的体粘滞系数的实验测量结果,估算了这种方法的测量误差,实验和理论分析都表明这是一种直接测量水的体粘滞系数的快速而精确的方法。     

输运过程的一般计算

本文用一般的分子运动的理论，以粘滞现象为例计算了输运系数。     

活细胞核浆粘滞系数的荧光相关谱研究

细胞核浆粘滞系数直接反映一定生理状态下核内微环境的特性,是判断病变细胞和研究核内分子功能机制的重要依据。为了实时、灵敏和无损地测定单个活细胞的核浆粘滞系数,提出了一种基于荧光相关谱(fluorescence correlation spectroscopy, FCS)技术的新型检测方法。研究中利用FCS技术测定绿荧光蛋白分子(EGFP)在细胞核内的扩散系数,并且根据Stokes-Einstein关系式计算出核浆粘滞系数,同时实现了对特定生理条件下核浆粘滞系数的跟踪测量。结果表明：在pH 7.4以及37 ℃的条件下,人肺腺癌细胞(ASTC-a-1)和人宫颈癌细胞(HeLa)的核浆粘滞系数分别是(2.55±0.61)cP和(2.04±0.49)cP, 与传统方法的测量结果一致,并且发现核浆粘滞系数大于细胞质的粘滞系数。以上研究表明FCS技术可精确无损地检测单个活细胞内达飞升量级的微观环境,是探索细胞内生物分子动态行为的有力工具。     

快度中心区强子物质输运系数和粘滞流体演化

用Chapman-Enskog方法计算了相对论性重离子碰撞快度中心区产生的π介子物质的输运系数,并建立了相应的粘滞流体力学方程,进而讨论了粘滞对π介子物质演化过程的影响.结果表明,粘滞将减缓快度中心区π介子物质的冷却速度.     

输运过程的一般计算

本文用一般的分子运动的理论，以粘滞现象为例计算了输运系数．     

浅析一种空气粘度的测量方法

基于流体力学原理,设想气垫导轨上的滑块与导轨间分为速度不同的空气层,结合空气粘性系数的求解方法,反向推导空气粘性系数表达式,得出空气粘度的计算式.通过将光杠杆原理测量得到的空气层厚度、滑块与导轨接触面积及空气粘性系数代入空气粘度的计算式,最终算出了实验条件下的空气粘度.     

液晶的转动粘质系数的测试原理与方法

液晶的转动粘质度是液晶用于显示和通讯的重要物理参量.本文设计开发了基于微机的液晶参数测试光学系统，在该系统上研究了液晶的转动粘质系数的测试原理与方法：通过测试液晶盒在偏置电压下相位驰预时间，推导出转动粘质系数的值.测试Merck公司的 E7液晶的转动粘质系数随温度变化的曲线，进行了理论拟合，测试结果与理论符合得很好.通过分析另一系统对液晶介质常数随温度变化的曲线的测试结果，验证了该测试原理与方法的正确性.该测试方法具有简单、自动化的特点.     

Drag coefficient of a liquid domain in a two-dimensional membrane

Using a hydrodynamic theory that incorporates a momentum decay mechanism, we calculate the drag coefficient of a circular liquid domain of finite viscosity moving in a two-dimensional membrane. We derive an analytical expression for the drag coefficient which covers the whole range of domain sizes. Several limiting expressions are discussed. The obtained drag coefficient decreases as the domain viscosity becomes smaller with respect to the outer membrane viscosity. This is because the flow induced in the domain acts to transport the fluid in the surrounding matrix more efficiently.     

Coefficients of viscosity of a gaseous plasma

We present here an order of magnitude calculation for the coefficients of viscosity with the assumption that the drift velocity introduces asymmetry both in the single-particle distribution functionf ₁ and the correlation functionP(1, 2). These asymmetric parts have been estimated considering the self-relaxation of the system when the cause of drift velocity is suddenly removed. Using these, the kinetic part of the coefficient of electron viscosity has been calculated and the result fairly agrees with similar studies by others. The potential part of shear viscosity coefficient is found to be zero while both parts of the coefficient of bulk viscosity are non-zero.     

On relativistic kinetic gas theory: XIV. Transport coefficients of a binary mixture. General expressions

A relativistic method to calculate transport coefficients is developed for a binary mixture with arbitrary particle interaction. The heat conductivity, the diffusion coefficient, the thermal-diffusion coefficient, the shear viscosity and the volume viscosity are expressed in terms of relativistic omega integrals.     

蓖麻油粘滞系数公式的Origin拟合

蓖麻油的粘度系数对温度变化很敏感,国际公认的标准值只有几个特定温度下的数值,这给实际应用及教学中实验测量结果准确性的评价带来了较大的困难。采用落球法研究了蓖麻油的粘滞系数与温度的关系,根据测量小球在不同温度的蓖麻油中下落速度,借助于origin软件,得出了蓖麻油的粘滞系数随温度变化的经验方程。     

Density expansion of viscosity coefficient

The formalism developed earlier has been extended to obtain the density expansion of viscosity coefficient. The important role played by the Hartree average energy in obtaining an explicit temperature dependence for the density coefficients of the viscosity is demonstrated. The results obtained are compared with the available experimental data for the first density coefficient. A satisfactory agreement between theory and experiment is found.     

Diffusion coefficient and shear viscosity of rigid water models

We report the diffusion coefficient and viscosity of popular rigid water models: two non-polarizable ones (SPC/E with three sites, and TIP4P/2005 with four sites) and a polarizable one (Dang-Chang, four sites). We exploit the dependence of the diffusion coefficient on the system size (Yeh and Hummer 2004 J. Phys. Chem. B 108 15873) to obtain the size-independent value. This also provides an estimate of the viscosity of all water models, which we compare to the Green-Kubo result. In all cases, a good agreement is found. The TIP4P/2005 model is in better agreement with the experimental data for both diffusion and viscosity. The SPC/E and Dang-Chang models overestimate the diffusion coefficient and underestimate the viscosity.     

Equilibrium molecular dynamics simulation of shear viscosity of two-dimensional complex (dusty) plasmas

Shear viscosity is examined throughout the entire range of strongly coupled states of two-dimensional complex (dusty) plasma liquids (CDPLs). We have employed equilibrium molecular dynamics (EMD) simulation to compute the shear viscosity coefficients of CDPLs. In the strongly coupled liquid region, the values of valid viscosity coefficient can be estimated only in order of magnitude. The variations in the valid viscosity coefficients with screening strength (κ) and Coulomb coupling strengths (Γ) are observed. A systematic dependence of shear viscosity on κ is observed for an intermediate and higher Γ. The investigations showed that the position of the minimum viscosity coefficient shifts towards higher Γ as κ increases. The computational results for the entire range of liquid states of the strongly coupled dusty plasma obtained using the shear autocorrelation functions are in good agreement with the available simulation results and experimental data. It is shown that new simulations extended the range of plasma states (Γ, κ) used in our earlier simulation results for the existence of a finite minimum possible viscosity coefficient and it is also dependent on plasma states.     

Longitudinal viscosity of liquid alkali metals

Summary The viscosity coefficient entering sound wave attenuation is evaluated for the liquid alkali metals in an ion-electron plasma approach. It is shown that the contribution from electrical conduction, though small, is by no means negligible. The calculated longitudinal viscosity is very close to the measured shear viscosity contribution, the bulk viscosity being expected to be small in the present approach.