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     

The effect of ionic interaction on the miscibility and crystallization behaviors of poly(ethylene glycol)/poly(L‐lactic acid) blends

The effect of end groups (2NH₂) of poly(ethylene glycol) (PEG) on the miscibility and crystallization behaviors of binary crystalline blends of PEG/poly(L ‐lactic acid) (PLLA) were investigated. The results of conductivity meter and dielectric analyzer (DEA) implied the existence of ions, which could be explained by the amine groups of PEG gaining the protons from the carboxylic acid groups of PLLA. The miscibility of PEG(2NH₂)/PLLA blends was the best because of the ionic interaction as compared with PEG(2OH, 1OH‐1CH₃, and 2CH₃)/PLLA blends. Since the ionic interaction formed only at the chain ends of PEG(2NH₂) and PLLA, unlike hydrogen bonds forming at various sites along the chains in the other PEG/PLLA blend systems, the folding of PLLA blended with PEG(2NH₂) was affected in a different manner. Thus the fold surface free energy played an important role on the crystallization rate of PLLA for the PEG(2NH₂)/PLLA blend system. PLLA had the least fold surface free energy and the fast crystallization rate in the PEG(2NH₂)/PLLA blend system, among all the PEG/PLLA systems studied. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

采用乙二醇二缩水甘油醚研究明胶的交联行为

制备13wt%的B型明胶缓冲溶液,然后加入1wt%～15wt%的乙二醇二缩水甘油醚(EGDE)在pH值等于7.4～11下进行交联。通过测量吸水率,红外光谱和13C-NMR分析,来研究其交联反应。明胶的氨基官能团完全被10wt%的EGDE消耗掉。对于3wt%的EGDE或3wt%以上的EGDE,pH值从7.4增至9.0过程中,吸水率下降。这种趋势在pH值>9.0时倒置,可能是由于明胶变性,以及交联反应中过量氢氧根离子干扰造成的。     

新建工科院校应用型工程教育探讨

黑龙江工程学院是一所新建工科院校,是世纪之交一批由高工专升本的教学型工科院校之一.这批工科院校的产生是在我国经济快速发展、高等教育进入大众化阶段的社会历史背景下,高等工程教育新的结构调整和分工.可以说,这一类型的工科院校不应是原来专科的简单放大和拓展,也不应盲目攀高进行脱胎换骨的改造,更不能亦步亦趋地模仿跟踪现有本科院校模式,其新的职能和定位是应用型工程本科教育.如何开展应用型工程教育,这是新建工科院校一直努力探讨和实践的课题.本文结合黑龙江工程学院的办学实践,对应用型工程教育问题作一点粗浅的探讨.     

真空蒸馏脱硒的研究

本文从理论上分析了真空蒸馏脱Se的影响因素时间和温度,并通过实验给予验证,提出了最佳条件,对工业采用真空蒸馏脱出含Se物料中的Se具有一定的指导性。     

钛硅分子筛催化环己酮氨肟化反应过程--本征动力学

对钛硅分子筛(HTS)催化环己酮氨肟化反应本征动力学进行了研究。利用经验方程拟合了试验数据，并采用Marquardt算法对经验方程的参数进行确定，获得了不同试验条件下的反应初速率，然后再用高斯-牛顿法对本征动力学模型进行了参数估计，得出了氨肟化反应以及该反应体系中H2O2分解的本征动力学。并对该模型进行了残差分析和F检验，对氨肟化反应和H2O2分解的动力学模型的计算值与试验值进行了比较，获得相对误差绝对值的平均值分别为5．21％和6．25％。表明该模型能真实反映HTS催化环己酮氨肟化的反应特性，是合理可靠的，能为进一步的过程开发与工程设计提供一些理论上的指导和设计上的依据；而H2O2分解副反应动力学模型仅适用于该反应体系。     

电冰箱节能潜力的研究

本文首先简要讨论了一些用于电冰箱的节能措施。然后通过ERA软件及自行编制的软件计算了使用这些措施后电冰箱的能耗情况。为了分析这些措施的可行性。继而进行了回收期和生命周期成本计算。分析结果表明，这些节方法不仅技术上能够实现，而且在经济上也具有可操作性。     

聚丙烯增韧改性研究进展

综述了国内增韧改性聚丙烯的研究动向 ,介绍了近年来茂金属聚烯烃弹性体和有机/无机纳米粒子增韧聚丙烯的新技术     

全固态氨气传感器

概括了目前氨气传感器的国内外发展状况，提出了传统电化学气体传感器存在的问题，介绍了一种利用Nafion膜为固态电解质的氨气传感器，阐述了它的工作原理，对电极材料、薄膜材料、固态电解液、电路等关键技术进行了讨论，重点介绍了电极的活化、液态电解质的固化及传感器的抗干扰、抗恶劣环境影响等技术研究，给出了传感器的结构和电路原理图，讨论了传感器的性能特点和发展方向。     

Comparison of physical characteristics and cell culture test of hydroxyapatite/collagen composite coating on NiTi SMA: electrochemical deposition and chemically biomimetic growth

A hydroxyapatite (HA)/collagen (COL) composite coating on NiTi shape memory alloy (SMA) was prepared by eletrochemical deposition (ELD) in modified simulated body fluid (MSBF). To draw comparisons of physical characteristics and bioactivity of the composite coating, the HA/COL composite coating was also prepared by chemically biomimetic growth (BG) and the ELD coating was re-soaked in MSBF again for further biomimetic growth (called EBG method in this paper). It was indicated that the c-axis of HA crystals was oriented parallel to the longitudinal direction of the COL fibril in BG and EBG coating, which could not found in ELD coating. The EBG method could induce a denser, thicker and better crystallized HA/COL coating. The cell culture test indicated that the BG coating presented better cell biocompatibility.