Calibration of Membrane Viscosity of the Reconstituted Vesicles by Measurement of the Rotational DIffusion of Bacteriorhodopsin

Membrane viscosity of the reconstituted vesicles was calibrated by rotational diffusion of bacteriorhodopin(BR) in dimyristoylphosphatidylcholine(DMPC) and egg phosphatidylcholine(PC) vesicles.Rotational diffusion of BR in the vesicles was measured by flash-induced absorption anisotropy decay.BR was,for the first time ,reconstituted successfully into DMPC and egg PC vesicles,From the measurement of flash-induced absorption anisotropy decay of BR,the value of rotational diffusion coefficient D was obtained from each curve fitting by a global fitting procedure and ,in turn,membrane viscosity η was estimated from D.The results have shown that membrane viscosity is temperature-dependent,It was decreased as temperature increased,but a transition occurred in the region of the respective phase transition of DMPC and egg PC,respectively,The decrease of η was fast near the phase transition for DMPC and egg PC.Few effects of lipid/BR ratio and glycerol or sucrose in suspension medium on membrane viscosity were found.     

介质的物化性质对PstⅠ和PstⅠ*活性的影响

利用限制性核酸内切酶PstⅠ在不同的有机介质中的催化反应,研究了水含量、相对粘度,介电常数和渗透压等介质的物化性质对PstⅠ原活性和星号活性的影响.结果表明这4种物化性质对PstⅠ原活性和星号活性的影响恰好相反.     

Bianchi Type-I Cosmology with Cosmic String and Bulk Viscosity

Some locally rotationally symmetric Bianchi type=I cosmological solutions for a cloud string with bulk viscosity are presented. In the first case, an equation of state ρ = κλ and the relation between metric potentials R = AS^m are considered, and the solution represents shearing non-rotating model with the bulk viscosity ζ∝ρ^1/2, where ρ is the rest energy density of the cloud of strings with particles attached to them, λ is the tension density of the cloud of strings, ζ is the coefficient of the bulk viscosity, R and S are only the functions of time t, while A and κ are constant. In the second case, the constant coefficient of bulk viscosity is considered.     

测量液体粘度实验的改进

在落球法测液体粘度的基础上，利用阿特武德机控制小球的运动速度和方向，从而突破了原落球法测液体粘度的局限性，且丰富了该实验的物理思想和内容，并作为一个综合性、设计性实验应用于教学之中。     

A fiber-array probe technique for measuring the viscosity of a substance under shock compression

A fiber-array probe is designed to measure the damping behavior of a small perturbed shock wave in an opaque substance, by which the effective viscosity of substance under the condition of high temperature and high pressure can be constrained according to the flyer-impact technique. It shows that the measurement precision of the shock arrival time by using this technique is within 2 ns. To easily compare with the results given by electrical pin technique, the newly developed method is used to investigate the effective viscosity of aluminum （Al）. The shear viscosity coefficient of A1 is determined to be 1700 Pa.s at 71 GPa with a strain rate of 3.6× 10^6 s-1, which is in good agreement with the results of other methods. The advantage of the new technique over the electrical pin one is that it is applicable for studying the non-conductive substances.     

倾斜管式液体粘度测量方法理论及实验研究

本文提出了一种适用于高压下及低沸点物质液相粘度的测量方法-倾斜管式粘度测量方法,并设计和搭建了粘度测量系统.采用粘度测量系统标定的标准物质-纯水,通过测量其运动粘度,对该测量系统进行了检测.结果显示,该测量系统的相对偏差绝对平均值为0.65%,验证了该方法原理的正确性及测量系统的准确性.此外,测量了R134a饱和液体的运动粘度,进一步检测了该粘度测量系统.     

Effect of water temperature on pulse duration and energy of stimulated Brillouin scattering

The water temperature has a strong effect on the kinematic viscosity, which is inversely proportional to the phonon lifetime and the gain coefficient. The higher the temperature is, the smaller the kinematic viscosity is, and the larger the phonon lifetime is. At a low pump power and a short focal length, we can derive a single-peak stimulated Brillouin scattering (SBS) pulse. The duration of this single-peak SBS pulse depends mainly on the phonon lifetime of water. With the increase of the water temperature, the duration of such a single-peak SBS pulse will become longer, and the SBS energy will become higher for the gain coefficient, which is related to the phonon lifetime. Therefore, varying the medium temperature can lead to the changes of SBS pulse duration and SBS energy.     

GLOBAL WELL-POSEDNESS OF THE 2D INCOMPRESSIBLE MICROPOLAR FLUID FLOWS WITH PARTIAL VISCOSITY AND ANGULAR VISCOSITY

This paper is concerned with the two-dimensional equations of incompress- ible micropolar fluid flows with mixed partial viscosity and angular viscosity. The global existence and uniqueness of smooth solution to the Cauchy problem is established.     

应用动态光散射和透射电镜研究热力学不相容条件下果胶与乳清蛋白混合体系的微观结构

应用动态光散射、透射电镜和粘度-剪切模型3种方法互相配合,研究了果胶与乳清分离蛋白的混合体系在热力学不相容条件下的微观结构。在90℃及pH7.4条件下,向5%蛋白浓度的乳清蛋白溶液中加入带有负电的果胶分子,可导致热变性乳清蛋白分子之间发生损耗聚集,并引发混合体系内的相分离现象。确切地说,当果胶与乳清蛋白的混合重量比小于0.08时,溶液内可观察到粒径小于300nm的聚集颗粒,体系呈现牛顿流体特征;而当混合重量比大于0.08时,体系粘度上升,切稀特征逐渐明显,聚集集团粒径接近700nm。     

饱和液体氦-3的粘度性质

文中揭示了低温液态氦-3在其饱和蒸气压下粘度随温度状态参数变化的反常规律,首次提出了3He在0.003K至其临界温度3.3157K温区内完整的气液相平衡曲线粘度方程。该方程计算值与高精度实验数据偏差小于±0.7%,并且在极低温条件下光滑过渡为由量子理论预测的理论极限。这项工作是研究氦-3在整个温度和压力区间上粘度性质行为特性的起点,不仅是构建全区间粘度方程的重要边界,而且对于理解费米-狄拉克量子统计规律在低温下的作用规律具有指导意义。