A two-parameter model for three types of nuclepore filtration of leukocytes

I.Intr0ductionWhenbloodcellspassthr0ughthefiltermembraneorthecapillaries,theypresentsimilarcharacteristicsIl'l,sothetechniqueofthenucleporefiltrationofcel1suspensionshasbeenextensivelyappliedtothestudyofbloodcellrheology.Therheologicalpropertiesofleuk0cy…     

Effect of the distributary of nasal meatuses on olfaction

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三维斯托克斯流动在扁球坐标系中的基本解及其应用

通过把Lamb基本解中的调和函数转换为扁球坐标系下的表达式,这项研究成功地得到了一个新的Stokes流动三维基本解.此基本解可用于解决任意多个扁椭球处于任意位置和方向时的流动问题.应用最小二乘法,三维流动问题中常遇到的收敛性差的困难在此得以完全克服.结果表明该方法具有准确度高,收敛性好和计算量小的特点.由于扁球可用于模拟从圆盘到圆球的多种物体形状,此基本解被用于系统地分析了各种几何因素对两个扁球所受力和力矩的影响.为了显示此方法的通用性,该基本解还用于研究了两例三个扁球的问题.     

跨膜渗透的流体力学分析

当两种浓度不同的溶液被一个多孔屏障(例如膜)分开的时候,溶剂(例如水)会由浓度较低的一侧流向另一侧,这种流动叫做渗透流。这时如要完全恢复两侧溶液间的平衡,可在浓度较高的一侧加上一定的压力,使得渗透流量变为零。这一压力的大小叫做此二溶液间的渗透压差。一种溶液与纯溶剂之间的渗透压差定义为它的渗透压。渗透现象不仅在化工等部门中有所应用,而且对于人和各种动植物的生命活动具有特别重要的意义。例如,跨越所有活体细胞的原生质膜,以及通过人体或动物许多器官(如肾小管、毛细血管、小肠、膀胱和角膜)的内外皮细胞间隙,都有渗透流。又如,人造器官的合成膜以及植物细胞与组织间的水交换等,都与渗透有关。因此,近三十年来,生物物理、生理学和流体力学工作者从不同角度对于渗透现象的宏观描述和微观机理进行了广泛的探索。     

THE MOTION OF A SPHERICAL PARTICLE IN THE STOKES FLOW OUTSIDE A CIRCULAR ORIFICE

For any study of a suspension entering a pore,the knowledge of the force and momentexerted on a solute parficle in an arbitrary position outside the pore is essential.This paperfor the first time presents approximate analytical expressions(in closed form),of all thetwelve force and moment coefficients for a sphere outsied a circular orifice,on the basis of anumber of diserete data computed by Yan et al(1987),These coefficients are then appliedto calculate the trajectory and angular velocity of a spherical particle approaching the poreat zero Reynolds number.The trajectory is in excellent agreement with the availableexpermental results.An analysis of the relative importance of the coefficients shows thatthe rofation effect cannot be neglected near the pore opening or near the wall and that thelateral force effect must be taken into account in the neighborhood of the edge of the pore etlg"‘!/‘lh(‘pol‘eopening It is due to neglecting these factors that previous theoretical results deviate fromthe exper     

LUBRICATION ANALYSIS OF A CELL SLIDING INTO A CIRCULAR PORE

The resistance to the blood cells at the entrance to capillaries and membrane porescontributes considerably to the peripheral resistance in the blood circulation.This paperproposes,for the first time,a simplified mechanical model in an attempt to treat theaxisymmetric motion of a cell sliding into a circular pore.In this model,the shape of the cellis taken as given according to the microvideograph and the cell membrane is assumed toslide over its surface.The lubrication theory is applied to the thin layers of plasma betweenthe membrane and the pore wall,yielding the pressure and shear stress distributions over themembrane as well as the resultant drag exerted on the cell.Our computations havesimulated the process of the cell entering the pore,which is in qualitative agreement with themicrovideographic observations.     

Moving Boundary Problem for Diffusion Release of Drug from a Cylinder Polymeric Matrix

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云纹等高线在人体检验中的应用

将生物力学的研究与人体检验相结合是一项值得重视的工作.利用 Moiré方法检验人体在文献[1,3]中曾进行过介绍.采用 Moiré法光学系统简单、操作容易、所用光源对人体无损害,它直接拍摄的照片可在病历中长期保存,是 ...     

在流体力学教学中通过重大事件实例教书育人

 在流体力学教学中适当地穿插讲述一些有关的重大事故、重大 灾害和重大建设项目(统称“重大事件”)，对于学生认识现在的学习 与未来工作之间的关系，提高学习自觉性，培养热爱专业的思想和严 谨的科学作风很有帮助. 本文简介我们在北大力学系本科生流体力学 教学实践中收集和讲述的部分重大事件实例.     

滤膜孔径误差对滤液流量-压力关系的影响

由于滤膜所含大量膜孔的半径的不均一性,以及说明书所给滤膜的名义孔半径与实际膜孔半径的算术平均值之间不一致,在计算滤液的流量-压力关系时,需对经典的泊肃叶定律加以修正.本文从概率论的观点讨论了如何对上述膜孔径加工误差的影响进行修正.