骨组织工程PLGA/TCP复合材料的性能研究

骨组织工程的支架要求有与人骨在功能梯度上相一致的材料结构、几何结构和生理功能。PLGA／TCP复合材料具有适用于骨组织工程支架的综合性能。以快速成形技术低温沉积工艺的成形效果来评价材料的成形性能，以体外降解试验来评价材料的降解性能，以国家标准的方法来评价材料的细胞毒性，对PLGA和TCP不同配比下的性能进行了研究，发现TCP含量的增加有利于降低材料的细胞毒性，加快了材料的降解，但同时降低了材料的成形性能。从骨组织工程的临床应用来看，低的细胞毒性是需要首先得到保证的，成形性能则通过其他方式来改善。     

丙烯腈吸收塔放空管道噪声控制

某石油化工总厂丙烯腈车间的吸收塔在放空负荷增大以后产生了较严重的噪声,对生产环境造成极大污染。为对丙烯腈吸收塔的放空管道实施噪声控制,改善工厂以及周边厂家的生产环境,进行了噪声控制方案设计及消声器设计。项目实施后,噪声绝对值降低了20分贝,噪声幅度降低达24％。     

Epoxidation of high trans‐1,4‐polyisoprene and its properties

A new organic‐solvent‐free water‐phase suspension method was used to synthesize partially epoxidized high trans‐1,4‐polyisoprene (TPI) to improve its properties, including oil resistance and wet‐skid resistance. The epoxidation was conducted in an aqueous peracetic acid solution and on the TPI granules prepared by a bulk precipitation method with supported titanium catalyst. The effects of the synthesis conditions, including reaction temperature, reaction time, and pH value, on the epoxy content were investigated. Epoxidized trans‐1,4‐polyisoprene (ETPI) with epoxy contents between 10 and 80% were obtained within 4 h. Both the amorphous and crystalline regions of TPI were epoxidized. The crystallization properties decreased with increasing epoxy content. ETPIs possessed lower mechanical properties than TPI but could be enhanced by vulcanization. The oil resistance and wet‐skid resistance were significantly improved after epoxidation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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     

Flexural and Shear Rigidity of Composite Sheet Piles

The flexural and shear rigidity of pultruded composite sheet pile panels consisting of E-glass fiber-reinforced polyester are studied in this paper. The analysis consists of an experimental investigation and an analytical modeling to determine the resistance of the sheet pile panels to the deflections for design of composite sheet pile walls. Timoshenko’s beam theory was used to experimentally determine the flexural rigidity (EI) and shear rigidity (kAG) of the panel. Three- and four-point bending tests were performed on six different span lengths and the results were self-compared from the two independent tests. Analytical expressions for the flexural and shear rigidities were derived to allow the prediction based on the layered structure of pultruded shapes. The values computed from the analytical expressions were examined with the experimental results.     

数字聚焦微电阻率测井仪设计

提出了一种采用数字聚焦方法的微电阻率测井仪器设计方案，其主要特点利用DSP集成芯片的数字信号处理优势，实现仪器的控制与测量，并通过软件滤波和聚焦处理获得视电阻率。该设计用超大规模集成电路DSP及软件处理取代了老式微球形聚焦测井仪器复杂的硬件监控、反馈、检波和测量线路，提高了仪器的可靠性和测量精度。对仪器原理进行了较详细的说明，在DSP技术应用于测井井下仪器方面做了有益的探索。     

低压补偿滤波装置的应用分析

用实例对比了低压补偿滤波装置与传统的无功补偿装置对工业用户无功补偿的作用和安装，运行、维护情况，阐明了低压补偿滤波装置是一种兼顾了补偿和滤波功能，具有较高的技术性和经济性的无功补偿和谐波滤波装置。     

A Standard Model-Theoretic Approach to Operational Semantics of Recursive Programs

In this paper we try to introduce a new approach to operational semantics of recursive programsby using ideas in the“priority method”which is a fundamental tool in Recursion Theory.In lieu ofmodelling partial functions by introducing undefined values in a traditional approach,we shall define apriority derivation tree for every term,and by respecting the rule“attacking the subterm of thehighest priority first”we define transition relations,computation sequences etc.directly based on astandard interpretation which includes no undefined value in its domain.Finally,we prove that ournew approach generates the same operational semantics as the traditional one.It is also pointed outthat we can use our strategy to refute a claim of Loeckx and Sieber that the opperational semanticsof recursive programs cannot be built based on predicate logic.     

一类三元线性分组码的译码

Ｐｌｅｓｓ［１］证明了三元（１２，６，６）Ｇｏｌａｙ码具有一种双层结构，并据此给出了该码的快速硬判决译码算法。本文推广了Ｇｏｌａｙ码的Ｐｌｅｓｓ结构，给出了由三元（ｎ，ｋ，ｄ）线性分组码构造的三元（３，ｎ＋ｋ，≥ｍｉｎ（ｎ，２ｄ，６））线性分组码，其中包括（１２，６，６）Ｇｏｌａｙ码和（１８，９，６）码，并以三元（１８，９，６）码为例给出了这类码的最大似然软判决译码算法。