Numerical surface characterization of wear debris from artificial joints using atomic force microscopy

Study on surface features of wear particles generated in wear process provides an insight into the progress of material failure of artificial joints. It is very important to quantify the surface features of wear particles in three dimensions. In this study, a new approach using atomic force microscopy was proposed to carry out 3D numerical surface characterization of wear debris generated from artificial joints. Atomic force microscopy combined with image processing techniques was used to acquire appropriate 3D images of wear debris. Computerized image analysis techniques were then used to quantify surface texture features of wear debris such as surface roughness parameters and surface texture index. The method developed from the present study was found to be feasible to quantity the surface characterization of nanoand micro-sized wear debris generated from artificial joints.     

劣质绝缘子电场正问题优化算法分析

针对劣化绝缘子的电场法检测中绝缘子电场计算精度低的问题,提出基于遗传算法优化的模拟电荷法进行高压静电场计算,给出了优化方法原理、可行性分析,建立了绝缘子电场计算目标函数及优化模型,并进行了绝缘子串周围电场的计算分析.分析结果表明,将绝缘子串周围检测点电位作为目标函数,应用遗传算法优化模拟电荷的电荷量,可更好地对目标函数进行全局寻优,提高了模拟电荷法的寻优速度、绝缘子串周围电场的计算精度以及绝缘子串中劣质绝缘子诊断的准确度.     

多媒体网络中的时延控制方法

时延和时延的抖动是多媒体网络中两个重要的参数,它们与网络的服务质量相关．提出了一种新的网络时延和时延抖动的控制方法——按时服务原则．该方法以虚拟时钟算法为基础,吸收了Ｊｉｔｅｒ－ＥＤＤ算法的优点,能够同时对时延和时延抖动进行控制．同以往的时延和时延抖动控制算法相比,其优点在于：无需为会话建立通信模型,只要是受漏桶（ＲＳ,Ｄ０）限制的会话,那么,该会话在按时服务器组成的网络中就存在一个最大时延Ｔ１,ＭＳ,ｍａｘ．     

3,5-diCl-PADMA光度法同时测定钴、钯的研究

本文提出了以2—(3,5—二氯—2—吡啶偶氮)—5—二甲氨基苯胺作显色剂同时测定钴、钯的新方法。在实验条件下,钴、钯与试剂分别形成1∶2和1∶1的稳定配合物。其表现观摩尔吸光系数分别为ε(?)=1.16×10~5L·mol~(-1)·em(-1),ε(?)=7.68×10~4L·mol~(-1)·cm~(-1)。钴浓度在0—0.6μg·ml~(-1),钯浓度在0—0.4μ·ml~(-1),范围内符合比尔定律。本方法简便、快速、选择性高,用于分子筛中微量钴、钯的同时测定,结果满意。     

Decay of geometry for unimodal maps: The C2 case

We prove that a C2 unimodal interval map with critical order not greater than 2 has the decay of geometry property, by showing that all the cross-ratio estimates needed in the previous proof for the C3 case remain true.     

茶毛虫核型多角体病毒DNA性质的研究

本文报道了对茶毛虫核型多角体病毒蒙山株系(EpNPV-M)核酸性质研究的结果。EpNPV-M含双链DNA分子,含量为6.85μgDNA/mgPIB,提纯的DNA具典型的紫外线吸收特性,琼脂糖凝胶电泳证明DNA分子是大小均一的。DNA的(G+C)％为36.6,限制性片段积加法测得该DNA分子量为75.61×10~6道尔顿,109.57Kb,电镜法测得DNA分子长度为35.8μm,相当于分子量为74.1×10~6道尔顿,107.4Kb.电镜观察证实该病毒含有一些超螺旋环状DNA分子。建立了三种限制性内切酶对该DNA的酶切图谱。三种酶的酶解片断数为:EcoRI,27个;BglⅡ,15个;BamHI,9个。     

鱼类消化酶的活性及环境条件的影响

探讨了鱼类蛋白酶、淀粉酶的活性,分布情况以及鱼生长、食性与消化的关系和环境条件对其活性的影响,提出了开展鱼类消化酶研究的意义。     

Effectiveness of sodium silicate as gangue depressants in iron ore slimes flotation

The recovery of iron from the screw classifier overflow slimes by direct flotation was studied. The relative effectiveness of sodium silicates with different silica-to-soda mole ratios as depressants for silica and silicate bearing minerals was investigated. Silica-to-soda mole ratio and silicate dosage were found to have significant effect on the separation efficiency. The results show that an increase of Fe content in the concentrate is observed with concomitant reduction in SiO₂ and Al₂O₃ levels when a particular type of sodium silicate at a proper dosage is used. The concentrate of 58.89wt% Fe, 4.68wt% SiO₂, and 5.28wt% Al₂O₃ with the weight recovery of 38.74% and the metal recovery of 41.13% can be obtained from the iron ore slimes with 54.44wt% Fe, 6.72wt% SiO₂, and 6.80wt% Al₂O₃, when Na₂SiO₃ with a silica-to-soda mole ratio of 2.19 is used as a depressant at a feed rate of 0.2 kg/t.     

谈面向对象编程

近年来，在计算机软件业，面向对象的程序设计的思想已经被越来越多的设计人员所接受．面向对象的编程(OOP)和数据抽象已经成为最常用的编程术语．本文以C 为例，讨论OOP的编程风格与特性．     

应急背景下制造企业成功转产的决定因素研究——基于企业能力理论的视角

基于动态能力理论和价值链理论,通过跨案例研究新冠疫情下格力、比亚迪、中石化、爹地宝贝、三枪集团和宇通集团等6家成功转产应急医疗防护品的企业,揭示疫情等应急背景下制造企业成功转产的决定因素,为更多的制造企业在应急背景下实现成功转产提供理论指导.根据企业在转产时原有产业与所转产产业的相关性,将其分为跨界转产和相关转产两类.研究表明:无论是跨界转产还是相关转产,企业的动态能力都起到了决定性作用;推动企业跨界转产的动态能力主要有洞察能力、学习能力、资源组合能力;推动企业相关转产的动态能力主要有洞察能力、学习能力、资源重构能力.