Development of composite tissue scaffolds containing naturally sourced mircoporous hydroxyapatite

The aims of this work were to investigate the conversion of a marine alga into hydroxyapatite (HA), and furthermore to design a composite bone tissue engineering scaffold comprising the synthesised HA within a porous bioresorbable polymer. The marine alga, Phymatolithon calcareum, which exhibits a calcium carbonate honeycomb structure, with a natural architecture of interconnecting permeable pores (microporosity 4–11 μm), provided the initial raw material for this study. The objective was to convert the alga into hydroxyapatite while maintaining its porous morphology using a sequential pyrolysis and chemical synthesis processes. Semi-quantitative XRD analysis of the post-hydrothermal material (pyrolised at 700–750 °C), indicated that the calcium phosphate (CaP) ceramic most likely consisted of a calcium carbonate macroporous lattice, with hydroxyapatite crystals on the surface of the macropores. Cell visibility (cytotoxicity) investigations of osteogenic cells were conducted on the CaP ceramic (i.e., the material post-hydrothermal analysis) which was found to be non-cytotoxic and displayed good biocompatibility when seeded with MG63 cells. Furthermore, a hot press scaffold fabrication technique was developed to produce a composite scaffold of CaP (derived from the marine alga) in a polycaprolactone (PCL) matrix. A salt leaching technique was further explored to introduce macroporosity to the structure (50–200 μm). Analysis indicated that the scaffold contained both micro/macroporosity and mechanical strength, considered necessary for bone tissue engineering applications.     

Analytical prediction of composite beams response in fire situations

In this paper an extension of the method of the Fourier series expansion to the fire analysis of composite beams is presented. In particular the extension concerns the introduction of the temperature dependent interaction of all the components: steel beams, concrete slab and steel connectors. These last are considered of finite stiffness, and a proper account is given to the combined effect of thermal degradation of the properties, and stress amplification caused by the differential thermal expansion across the interface.The proposed method compares very well with some experimental fire tests of simply supported and framed composite beams. Due to its relative simplicity and speed, it can be used for design purposes in evaluating the critical temperature in terms of critical deflection. Finally we recall that the method is capable of dealing with every type of fastening distribution, such as discontinuous or variable length.     

Composite scale modeling in the presence of censored data

A composite scale modeling approach can be used to combine several scales or variables into a single scale or variable. A typical application is to combine age and usage together to form a composite timescale model. The combined scale is expected to have better failure prediction capability than individual scales. Two typical models are the linear and multiplicative models. Their parameters are determined by minimizing the sample coefficient of variation of the composite scale. The minimum coefficient of variation is hard to apply in the presence of censored data. Another open issue is how to identify key variables when a number of variables are combined. This paper develops methods to handle these two issues. A numerical example is also included to illustrate the proposed methods.     

传爆管用聚奥99炸药研究

介绍了具有高煤轰感度和耐热特性的聚奥99炸药的配方、制备工艺、性能以及装入传爆管后产品的性能和应用状况。     

SiC颗粒尺寸及含量对SiCp／2024Al复合材料性能的影响

本文对粉末冶金法制备的SiCp/2024Al复合材料的性能进行了研究。随SiC颗粒尺寸的增大,复合材料的强度降低,而塑性和磨损抗力则增加。SiC颗粒尺寸对复合材料的物理性能没有什么影响。增加SiC颗粒含量,复合材料的强度、模量均增大,磨损抗力亦明显增加,而塑性和热膨胀系数则降低。     

预报复合材料热膨胀系数的细观力学模型

建立了一国观力学模型用于预报复合材料的有效热膨胀第数。利用这一模型计算热膨胀系数无需对复合材料进行热应力分析，仅需知道在某一相关外力场作用下，其组分的内部的平均应力场问题即可解决。     

CFG桩法的设计及施工

CFG桩复合地基是一种新型的地基处理技术 ,本文对其作用原因、设计方法、施工及质量检测等方面进行了初步探讨。     

应用型本科院校材料科学与工程专业复合材料方向特色人才培养的探索与实践

随着社会对人才需求层次的不断提高,各本科高校都在从教育教学方式、专业特色方向等方面着手进行特色人才培养的探索,旨在培养适应社会需求的高层次人才。吉林化工学院为了适应东北地区经济及社会的发展需要,在材料科学与工程专业的人才培养方案中引入复合材料专业方向,并在该专业方向中坚持理论教学与科研相结合的特色,在教师队伍、实践平台、培养方案等方面进行了探索与实践,并取得了较好的成效。     

表面工程技术在导弹武器装备维修中的应用

本文主要介绍铝/F_(46),协合涂层新技术、复合电刷镀Ni—PTFE新工艺、DJB—823电接触保护剂及三防电子器件绝缘清漆在二炮导弹武器装备维修中的应用。