复合材料层板冲击破碎实验 与数值评估方法

纤维增强复合材料层板是电路板基板的重要组成部分, 预测其破碎过程是废旧电路板破碎机设计的重要依据.首先, 基于实验测得复合材料层板的冲击能量, 对比面内和面外两种冲击破碎方式.然后, 基于Hashin损伤理论建立复合材料层板冲击破碎预测模型, 预测的冲击消耗能量与冲击速度与实验结果吻合度高, 表明Hashin损伤理论可以应用于玻璃纤维复合材料层板冲击破碎问题.通过复合材料层板的面内和面外冲击损伤过程对比分析, 发现面内冲击破碎可以避免层间开裂造成的额外能耗, 所以沿平面方向的冲击破碎效果要好于沿厚度方向的破碎效果.当前冲击损伤预测模型可进一步应用于预测电路板基板的破碎过程, 也可用于指导电路板破碎机传动系统设计.      

The influence of fibre pretreatmert on the mechanical properties of epoxy-asbestos composites

This study is devoted to the mechanical properties of asbestos-epoxy composites. Chrysotile fibres were first pretreated by means of an interfacial polymerization technique effecting eventually a poly (hexamethylene adipamide) coating on the asbestos surface. The interface characteristics were significantly altered and due to the well-known compatibility between epoxy and polyamide phase considerable deviation from the behaviour encountered when using untreated fibres was confirmed. Accordingly, while varying pretreated fibre content and also concentration of the polyamide coating, the tensile properties of the resulted composites were examined.     

老采空区上建设项目地质灾害危险性评估

老采空区地下采煤活动强烈,地质环境条件相对复杂,在附加荷载作用下存在“活化”的可能性。针对这些地质情况,以峰峰集团有限公司煤化工项目35kV变电站工程地质灾害危险性评估为实例,介绍了该类建设项目的地质灾害危险性预测评估的基本思路和分析方法,并以建筑物荷载影响深度、采空区导水裂缝带发育高度是否相互重叠,作为评价老采空区的活化、地基稳定性及其对建筑物影响的主要依据,对项目用地的适宜性作出了定量评价。     

Fenton氧化技术处理难降解工业有机废水研究进展

系统地分析了各种Fenton氧化技术对有机污染物的降解机理,概述了Fenton氧化技术在处理化工废水、印染废水、制药废水、农药废水和含油废水等难降解工业有机废水中的应用研究进展,认为拓宽Fenton氧化体系的pH响应范围,开展Fe2 /Fe3 固定化技术研究是今后的研究重点,Photo-Fenton和E1ectro-Fenton将是今后Fenton氧化体系的两大发展方向.     

Chebyshev economization for parametric surfaces

The communication of polynomial curve and surface data between various CAD systems frequently requires that a degree reduction be performed. The most common way of accomplishing this reduction at present is via ‘black box’ methods. In this note we extend the notion of Chebyshev economization from real polynomials to parametric polynomials in three dimensions, thus providing an analytical approach to degree reduction. More importantly, we propose a generalization for parametric surfaces which enjoys many of the properties associated with Chebyshev economization.     

A formula for computing the number of quadtree node fragments created by a shift

A formula is provided to compute the number of new blocks resulting from the decomposition induced by a shift of a single quadtree node of arbitrary size by an arbitrary amount. A precise calculation is also presented for the average number of Black nodes required to represent a square of width 2^m in a region quadtree.     

天津滨海地区水库水质咸化问题及机理分析

天津滨海地区的北大港水库和其他水库存在水质咸化问题.根据传质理论,结合滨海地区的自然地理和气候特点,全面地分析了滨海地区水库水质咸化机理,主要机理有盐碱土和地下水的传质作用、蒸发量大于降雨量的蒸发浓缩作用、风的搅拌加速传质作用和加速蒸发浓缩作用等.     

Strain rate dependent mechanical properties of new albany reference shale

Drilling, mining and blasting of rock-like materials, in situ fracturing, rock fragmentation size and permeability extension are strongly affected by strain rates of loading. For low strain rates, fragment sizes are large, and cracks propagate further. For high strain rates, fragment sizes are small and cracks are localized. The purpose of the present investigation is to determine the effects of strain rate on the initial (linear) value of Young's modulus and on Poisson's ratio for different grades of New Albany oil shale, a reference oil shale designated by the U.S. Department of Energy. Material anisotropy is considered. Cylindrical specimens cored in a particular orientation of the oil shale formation are tested in compression, and the rate effects are investigated. An efficient data acquisition/reduction system is developed, interfacing with an Instron closed-loop hydraulic testing machine. Strain gauge instrumentation is used to measure lateral and longitudinal strains. Strain rates of about 10⁻⁵–10⁰/sec are studied.     

城市配送车辆调度模型及算法设计

在分析城市货物配送和车辆调度特点的基础上,建立了追求总体效益最优的车辆调度多目标决策模型,并设计分派-节约启发式算法求解该模型。通过分派启发式算法保证最大程度地满足客户的要求,再利用节约算法保证了全局最优。最后对初始解进行局部和整体优化调整以得到较优解。基于该算法设计并开发了城市配送车辆调度系统,运行结果表明:该算法能够有效地解决城市配送的客户满意、总成本最低、配送车辆空载率最小的多目标决策问题。