Application of BGK Scheme on Micro-Channel Gas Flow

A modified gas kinetic Bhatnagar-Gross-Krook (BGK) scheme for microflow has been developed upon the simultaneous collision model. Based on experimental and numerical results, the sub-choked pressure ratios areinvestigated. The current numerical approach is validated to provide a practical solution for microchannel flow.     

研究意识问题的物理学途径

文章介绍了物理学理论和技术在研究意识问题中的应用进展。首先列出意识活动的一些主要特性，其次介绍新的仪器技术在确定意识的脑功能定位上的研究成果。最后介绍物理学的理论（特别是量子理论）在解释意识的机制上的作用，介绍信息理论在意识复杂性计算方面的应用。     

Growth and Characterization of Trumpet-Shaped ZnO Microtube Arrays on Si Substrates

Aligned trumpet-shaped zinc oxide microtube arrays have been successfully prepared on silicon （100） substrates via the chemical vapour deposition method with a mixture of ZnO and active carbon powders as reactants. The results show that two types of trumpet-shaped ZnO microtubes can be obtained. A plausible growth mechanism based on the studies of scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, x-ray diffraction （XRD）, and room-temperature photoluminescence spectroscopy is proposed and discussed. The initial metastable zinc-rich ZnOx embryos play a key role in the formation of trumpet-shaped ZnO microtubes. On the different surfaces of metastable zinc-rich ZnOx （x 〈 1）, embryos exhibit different stabilities and resistivities to oxidation; these tiny embryos are gradually extended with different growing rates along the directions of its long axis and circular boundary around its oxide shell. Just this special reason creates the formation of trumpet-shaped microtubes and results in the inerratic and imperfect hexagonshaped cross section that appears. Moreover, the analytical results also show that the as-synthesized ZnO microtube arrays can exhibit better room-temperature photoluminescence behaviour.     

微管壁上量子信息的传递

微管管壁上的原丝纤维可以描述成各项异性的二维赝自旋模型,其最小重复单元是三角形状的。在这个模型中存在三种不同的“自旋-自旋”相互作用。而每一维上的自由电子可以看作是赝自旋模型。那么,微管壁上的量子信息传递就可以用Lylod提出的激光控制量子计算的模型来解释。Microtubule （MT） is described as an anisotropic two-dimensional pseudo-spin model on a triangular lattice, in which there are three different ＂spin-spin＂ interactions. The mobile electron in each lattice site is described based on the pseudo-spin model. Then, the processing of quantum information in the MT wall is presented by virtue of the scheme of driving quantum computer in sequence of laser pulse developed by Lloyd.     

Electrical conductivity of individual polypyrrole microtube

Conducting microtubes (0.4－0.5μm in outer diameter) made of polypyrrole (PPy) doped with p-toluene sulfonic acid (PTSA) were synthesized by a self-assembly method. We report the electrical conductivity of an individual PPy microtube, on which a pair of platinum micro-leads was fabricated by focused ion beam deposition. The measured room-temperature conductivity of the individual PPy microtube was 0.29S/cm, which is comparable to that of template-synthesized PPy micro/nanotubes. The temperature dependence of conductivity of the individual microtube follows the three-dimensional variable-range hopping (3D VRH) model.     

6H-SiC单晶中的微管和小角度晶界

利用透射偏光显微术、同步辐射X射线形貌术、高分辨X射线衍射方法对6H-SiC(0001)晶片中的微管和小角度晶界等缺陷进行了研究.实验发现,在透射偏光显微镜下,微管通常呈现为蝴蝶形,这是由于微管周围存在着应力场,且应力分布不均匀,当线偏振光在通过微管周围区域时传播速度不同造成的.从X射线背反射同步辐射形貌像得到晶片中微管的Burgers矢量大小在2c到10c之间.从晶片00012衍射的双晶衍射摇摆曲线可以看出,晶片的中间大部分区域质量很好,双晶衍射峰为单峰且半峰宽很窄,一般为35"左右.在外围区域双晶衍射峰的半峰宽变宽,有些区域还会出现衍射峰的分裂,这说明外围区域有嵌镶块结构存在.     

软骨细胞黏弹性及恢复变形与年龄相关性研究

本文旨在表征年龄对软骨细胞在自然生长过程中的黏弹性和恢复变形能力的影响.结果表明:年龄对软骨细胞黏弹性及其恢复变形能力产生显著影响,老年组软骨细胞各项黏弹性参数值均明显高于幼年和中年组软骨细胞(p<0.000 1),而后两组无显著差异(p>0.05);老年组软骨细胞蠕变达到平衡态所需时间t_E显著小于幼年和中年组(p<0.05),而幼年和中年组无显著差异(p>0.05).老年组软骨细胞最大蠕变位移L_M显著大于幼年和中年组(p<0.005),而幼年和中年组无显著差异(p>0.05).老年组软骨细胞恢复变形时间t_R显著大于幼年和中年组(p<0.005),而幼年和中年组无显著差异(p>0.05).恢复变形前8s的分析发现,幼年组软骨细胞恢复变形率K_y显著高于中年和老年组(P<0.005),而中年组(K_α)和老年组(K_o)软骨细胞的恢复变形率无显著差异(p>0.05);此外,实验发现老年组软骨细胞的残余变形L_R比幼年和中年组显著增大(p<0.005),而后两组无显著差异(p>0.05).研究工作对于软骨组织工程、软骨细胞与支架材料相互作用以及探讨OA发生过程中的力学生物学机制具有理论意义.     

高压下液体微管道流动的摄动分析

应用参数摄动法对可压缩N-S方程进行渐近展开,并取其零阶近似对高压下微管道液体流动特性进行了分析．对任意截面形状和面积的微管道,在等温流动假设下将其截面形状、滑移长度等对解的贡献转化为求解该截面的格林函数,并给出等截面圆形微管道流动的零阶近似解．以此分析可压缩性、黏性以及壁面滑移等因素对高压下液体微管道流动特性的影响,进一步揭示了高压驱动下液体微管道流动偏离经典Hagen-Poiseuille(HP)理论的原因．      

Employment of Jacobian elliptic functions for solving problems in nonlinear dynamics of microtubules

We show how Jacobian elliptic functions （JEFs） can be used to solve ordinary differential equations （ODEs） describing the nonlinear dynamics of microtubules （MTs）. We demonstrate that only one of the JEFs can be used while the remaining two do not represent the solutions of the crucial differential equation. We show that a kinkbtype soliton moves along MTs. Besides this solution, we also discuss a few more solutions that may or may not have physical meanings. Finally, we show what kind of ODE can be solved by using JEFs.     

重力场作用下微管自组装过程中向列相取向的空间模式的形成

通过引入函数标度变换的方法,在理论上提出了细胞骨架微管溶液系统在重力场中的自由能函数,并在此基础上研究了重力场对微管系统自组装过程的影响.微管蛋白溶液中浓度梯度和排列具有向列相特征的空间结构模式的形成是重力场作用下出现的新特征.理论计算结果表明重力场会促使微管蛋白溶液从各向同性相向向列相转变,具体表现在它很大程度地拓宽了相变区域(即相共存区域),而且随着重力加速度或微管浓度的增加,相变区域会变得更宽.最后对定域微管浓度随溶液高度的变化情况及某些相变性质进行了讨论.