二维振荡流动中污染云团的收缩*

当垂向扩散时间尺度与流动的周期相当时,在转流过程中,污染云团将会出现收缩.这时水平剪切分散导数将会出现负值奇性.本文根据作者两维延迟扩散方程[7]: 其中u(t),v (t)为深度平均水平速度.导出X(t,τ),Y(t,τ)坐标位移,D_ij(t,τ)为剪切扩散导数的方程.一般情况下,?D_ij(t,τ)/?τ是正的.不存在奇异性.但在转流的初期.记忆函数D_ij(t,τ)就有可能是负的.本文给出了D_ij和X、Y的解析表示式.     

圆锥形血管中的振荡发展流动

本文在小锥度角的假设下,研究了圆锥形血管的非定常振荡的发展流动问题.导得了相应的速度分布公式.分析表明,所有收缩的圆锥形血管的流动都是发展流动,而且锥度角对发展流动的影响随着锥度角的增大而增大.     

Novel Highly Branched Polyester Nanoparticles(Ⅱ)──Interactions Between Anionic HBPNP articles and Cationic Surfactant,Cetyltrimethylammonium Bromide

The interactions between highly-branched anionic polyester nanoparticles (HBPN) and the oppositely charged surfactant (cetyltrimethylammonium bromide, CTAB) in a buffer (pH=12) were investigated by means of dynamic laser light scattering.     

含剧烈振荡波函数积分J(n,X)的研究(I)

在天体物理与等离子体有关的大量原子过程中,需要精确计算大量含剧烈振荡波函数的积分.直接数值积分既笨拙又不能保证所需精度。为此,对不同波数的情形,采用Belling渐近展开法,提高了其中位相的精度;对相同波数的情形,则给出了J(n,X)的解析表达式。计算模拟结果表明有足够高的精度.     

动态光散射对良溶剂中酚醛型聚醚砜的研究

用动态光散射方法研究了酚酞型聚醚砜(PES-C)在良溶剂DMF中的稀溶液性质。在稀溶液中,PES-C分子由于内旋转发生链折叠,整体上表现出柔性链的性质,较好的符合球形模型;而分子链的局部刚性结构又使分子尺寸稳定;它的扩散行为随温度的变化符合Arrehnius方程。表征了PES-C分子在稀溶液中的形态结构,且给出了PES-C分子在DMF中的扩散系数、扩散活化能、无限稀时的扩散系数和流体力学半径等重要特征参数。     

Weakly Nonlinear Oscillatory Waves with Multi-phases in Ideal Incompressible Fluid

In this paper, we apply the technique of weakly nonlinear geometric optics to study weakly nonlinear oscillatory waves with multi-phases in d-dimensional ideal incompressible fluid for d ≥ 2. Precisely, we give a rigorous asymptotic expansion for the solution of the oscillatory initial value problem to the ideal incompressible Euler equations. Generally, this problem is not well posed. However, the coherence assumption and small divisor property imposed on the phases functions lead to a compatibility condition for the solvability of profile equations from which we can determine every profile.     

Geometrically nonlinear analysis of mindlin plate using the incompatible bending elements with internal shear strain

ＧＥＯＭＥＴＲＩＣＡＬＬＹＮＯＮＬＩＮＥＡＲＡＮＡＬＹＳＩＳＯＦＭＩＮＤＬＩＮＰＬＡＴＥＵＳＩＮＧＴＨＥＩＮＣＯＭＰＡＴＩＢＬＥＢＥＮＤＩＮＧＥＬＥＭＥＮＴＳＷＩＴＨＩＮＴＥＲＮＡＬＳＨＥＡＲＳＴＲＡＩＮＪｉａｏＺｈａｏ－ｐｉｎｇ（焦兆平）（Ｓｏｕｔ...     

宁波港北仑港区冲淤里初探

本文根据北仑港区的水文资料,运用三种不同方法进行初步的冲淤计算。计算成果与北仑港区地形测量资料比较一致。分析了水动力条件,床面切应力以及地形等资料,认为目前本区是处于稳定阶段,水流足能把来沙带走。     

ANALYTICAL SOLUTION FOR THE SELFSIMILAR PROBLEMS OF VISCOUS FLUID FLOW

This paper presents a step-by-step approximating method to obtain the analyticalsolutions of the differential equations for the self-similar problems of viscous fluid flow(1.1-1.4).Prosnak(1969)obtained solutions of these equations by using a small paremetermethod,but he reduced the governing equations to the linear differential equations withconstant coefficients.     

HARMONIC SOLUTIONS OF SOME SECOND-ORDER NONLINEAR EQUATIONS UNDER A PERIODIC FORCE

In this paper we prove some theorems on the existence of harmonic solutions of somesecond-order nonlinear equations under a periodic force.These theorems extend relevantresults in refs.[1]-[8].