Accelerated wear testing with a microfabricated surface to evaluate the lubrication ability of biomolecules on polyethylene

Wear of ultrahigh‐molecular‐weight polyethylene (UHMWPE) and wear‐particle‐induced osteolysis and bone resorption are the major factors causing the failure of total joint replacements. It is feasible to improve the lubrication and reduce the wear of artificial joints. We need further understanding of the lubrication mechanism of the synovial fluid. The objective of this study is to evaluate the lubricating ability of three major components in the synovial fluid: albumin, globulin, and phospholipids. An accelerated wear testing procedure in which UHMWPE is rubbed against a microfabricated surface with controlled asperities has been developed to evaluate the lubrication behavior. An analysis of the wear particle dimensions and wear amount of the tests has provided insights for comparing their lubrication performance. It is concluded that the presence of biomolecules at the articulating interface may reduce friction. A higher concentration of a biological lubricant leads to a decrease in the wear particle width. In addition, in combination with the wear results and mechanical analysis, the roles of individual biomolecules contributing to friction and wear at the articulating interface are discussed. These results can help us to identify the role of the biomolecules in the boundary lubrication of artificial joints, and further development of lubricating additives for artificial joints may be feasible. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

建筑结构施工图设计常见质量问题分析

为贯彻落实国务院关于建设工程施工图设计文件审查制度,确保建设工程勘察设计质量,全国各地对建筑工程施工图设计进行了认真审查,特别是对结构设计施工图审查更为严格。工程结构设计施工图审查的重点是结构安全和强制性标准执行情况。经过审查发现,施工图一次性审查合格率不高,原因是建设结构施工图设计中违反国家强制性标准的情况较为普遍。究其原因,既有由于设计人员频于赶任务没有认真校审而出现的设计质量“通病”,诸如“错、漏、碰、撞”等问题,也有设计人员结构概念模糊,对强制性标准条文理解不深或未予高度重视等造成的严重错误。本…     

Using circuit model from layout-level synthesis as coarse model in space mapping and its application in modelling low-temperature ceramic cofired radio frequency circuits

The technique of using a coarse model obtained from layout-level synthesis of radio frequency components in neural inverse space mapping (NISM) optimisation technique is proposed. Layout-level synthesis is based on a combination of segmented lump-circuit modelling, nonlinear mapping using neural network (NN) and circuit-level optimisation. The circuit model based on the electromagnetic (EM) simulation describes the important parameters and parasitic parameters and serves as a high-quality coarse model in applying NISM. In implementation of NISM optimisation, trained NN is introduced as a buffer space between the original coarse model space and the fine model space, where the subset of the coarse model space is completely different from that of the fine model space. Stoer-Bulirsch adaptive frequency sampling (S-B AFS) technique is used in frequency sweep of the fine model to further reduce the computing time. An application design of low-temperature ceramic cofired filter is used to demonstrate the proposed technique. Synthesis and optimisation results of the filter meet the design specifications.     

影响GPS水准高程的因素及高程拟合方法的探讨

在简单介绍高程系统的基础上，对影响GPS高程精度的几何水准联测误差、卫星分布不对称、星历误差、多路径误差等因素逐一进行了分析，并提出了相应的改进措施。同时，还对高程拟合使用的稳健估计方法进行了探讨。     

丰满流域可能最大暴雨与可能最大洪水分析研究

依据丰满漉域的水文气象资料,计算丰满流域可能最大暴雨,推求白丰区间的可能最大洪水并进行成果合理性分析.     

Thermokinetics of Liquid-Liquid Reaction of Dy（NO3 ）3 with Histidine

The thermokinetics of liquid-liquid reaction of dysprosium nitrate with histidine were studied using a microcalorimeter. On the basis of experimental and calculated results, threethermodynamic parameters (the activation enthalpy, the activation entropy and the activation free enegy),the rate constant, three kinetic parameters (the activation energy, the pre-exponential constant and the reaction order) wereobtained. On the basis of thermodynamics and kinetics, the for marion reaction of the complex was discussed.     

MC^2电缆介质结构及阻抗分析

本文将用数学和实验两种方法证实MC～2电缆不仅能保证特性阻抗变化不超出电缆技术规范。而且能保证在设计频率范围内电缆结构反射损耗最小。     

化学镀Ni—P镀层的X射线衍射研究

根据X射线衍射分析结果,对化学镀高P(含P>11wt％或19at％)Ni-P镀层加热时效时,镀层成分和加热温度对结构转变的影响作了研究,结果表明,高P共晶、过共晶(含P>11wt％或19at％)合金的结构转变有如下特征:(1)相同加热时效条件下,Ni-P合金的结构转变与成分有密切关系:(2)对同一成分的过共晶合金,Ni-P合金的结构转变与时效温度密切相关;(3)过共晶合金在290～360℃温度范围内时效处理,出现Ni_xP_y介稳相,X射线衍射分析认为Ni_xP_y为Ni_(12)P_5。