新型纳米羟基磷灰石晶体复合抗菌剂的制备

以纳米羟基磷灰石为载体,聚乙烯醇为有机抗菌组分,铜离子和锌离子为无机抗菌组分,在一定条件下制备了有机/无机复合抗菌剂.运用XRD、IR和SEM等现代分析方法对复合抗菌剂中抗菌成分与载体的结合方式进行了分析、形貌进行了观测,并对其抗菌性和安全性能进行研究.结果表明,在聚乙烯醇含量为2.8;,铜离子和锌离子含量分别为10;和15;时,制备有机/无机复合抗菌剂具有优异的抗菌性能和安全性.     

正交各向异性功能梯度材料Ⅲ型裂纹尖端动态应力场

研究了无限大正交各向异性功能梯度材料Griffith裂纹受反平面剪切冲击作用的问题.材料两个方向的剪切模量假定为成比例按特定梯度变化.通过采用积分变换-对偶积分方程方法,获得了裂纹尖端动态应力场.动态应力强度因子计算结果显示:增加剪切模量梯度或增加垂直于裂纹面方向的剪切模量可以抑制动态应力强度因子的幅值.     

Fracture behavior of a bonded magneto-electro-elastic rectangular plate with an interface crack

In this paper the anti-plane problem for an interface crack between two dissimilar magneto-electro-elastic plates subjected to anti-plane mechanical and in-plane magneto-electrical loads is investigated. The interface crack is assumed to be either magneto-electrically impermeable or permeable, and the position of the interface crack is arbitrary. The finite Fourier transform method is employed to reduce the mixed boundary-value problem to triple trigonometric series equations. The dislocation density functions and proper replacement of the variables are introduced to reduce these series equations to a standard Cauchy singular integral equation of the first kind. The resulting integral equation together with the corresponding single-valued condition is approximated as a system of linear algebra equations which can be easily solved. Field intensity factors and energy release rates are determined numerically and discussed in detail. Numerical results show the effects of crack configuration and loading combination parameters on the fracture behaviors of crack tips according to energy release rate criterion. The study of this problem is expected to have applications to the investigation of dynamic fracture properties of magneto-electro-elastic materials with cracks.     

Nuclear parton distribution functions and energy-loss effect in the Drell-Yan reaction off nuclei

The energy-loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of two typical kinds of quark energy-loss parametrization and the different sets of nuclear parton distribution functions, we present an analysis of the E866 experiments on the nuclear dependence of Drell-Yan lepton pair production resulting from the bombardment of Be, Fe and W targets by 800 GeV protons at Fermilab. It is found that the quark energy loss in cold nuclei is strongly dependent on the used nuclear parton distribution functions. The further prospects of using relatively low energy protons incident on nuclear targets are presented by combining the quark energy-loss rate determined from a fit to the E866 nuclear-dependent ratios versus x ₁, with the nuclear parton distribution functions given from lA deep inelastic scattering (DIS) data. The experimental study of the relatively low energy nuclear Drell-Yan process can give valuable insight in the energy loss of the fast quark propagating through cold nuclei and help to pin down nuclear parton distribution functions.Received: 8 September 2004, Revised: 18 October 2004, Published online: 11 January 2005PACS: 24.85. + p, 13.85.Qk, 25.40.-h, 25.75.Nq     

气垫导轨实验中极限法测速度的分析与讨论

对线性外推法测气轨上滑块的瞬时速度实验进行理论分析,给出了-v-δt和-v-δs函数、其表达的物理意义及实验需满足的条件.     

Clifford分析中奇异积分的反转公式

借助于多元复分析的思想,本文用两种方法证明了Clifford分析中奇异积分的反转公式．     

动力机器地基随机振动研究

在土层中取一变截面土柱,从一维波动方程出发,采用复弹性模量,计及土的弹性模量沿深度的变化和阻尼影响,推导出动力机器简谐扰力作用下地基土垂直振动的位移,并在此基础上,计算出位于机器下方地基土对机器随机扰力的动力响应．