加宽道路施工新技术研究

结合某公路改建工程,提出在加宽路段使用新技术———强夯法施工.为达到提高加宽部分填土路基承载力、减少新老路面不均匀沉降的目的,寻求适宜的施工参数及施工工艺.强夯在该工程的应用,取得了较为满意的经济效果,验证了强夯运用的正确性,为进一步拓宽强夯法的应用范围打下了良好的基础,同时也可为此新技术在公路工程中推广应用拉开序幕.     

结构的行波控制

将结构的扰动视为行波的传播过程,通过主动控制波的传播路径,实现对结构扰动的控制。通过行波控制器的作用,扰动能量在上游被抑制或被吸收掉,使下游的能量达到最小。从理论上探讨了基于行波模型的结构梁响应控制方法,在梁及压电陶瓷作动器处采用行波理论模型,导出了上游测量、下游点施加控制的行波主动控制律及相应的具有超越函数形式的控制补偿器表达式。仿真结果表明行波控制能取得相当好的控制效果。     

刀具-工件接触动静刚度分析与计算研究

以回转体零件加工为例,考虑加工中变形及径向力的作用,对工件-刀具接触中动静刚度进行了分析与计算,提出了刚度系数的计算公式,并对其动态特性分析。结论与实验结果一致,从而为合理确定切削用量提供了一种途径。     

ERP教学系统之再生法MRP的系统分析与设计

在分析现有企业资源规划（Enterprise Resource planning，ERP）商用软件和国内少数ERP教学软件在高校ERP制造人才培养所具缺陷的基础上，依ERP制造系统原理最新教改成果，介绍单机版ERP教学软件中核心的再生法物料需求计划（Material Resource planning MRP）的模拟开发。在较简单静态材料表基础上，详细阐述集成冲销时间、逾期量及固定计划订单等因素的再生法MRP的系统分析与设计。该模拟开发巳能基本满足MRP核心,计划原理的教学需求，为后续动态材料表与重排计划建议等MRP高级功能的实现打下坚实基础。     

浅谈剑桥商务英语（BEC）口试备考技巧

剑桥商务英语考试根据公务或商务工作的实际需要,以听、说、读、写4个方面对考生在一般工作环境下和商务活动中使用英语的能力进行全面考查。针对此口试的形式和内容,在有的放矢,有针对性的训练；语法、词汇不容忽视；模仿、朗读,练就纯正语音语调；锻炼自我表达能力；乐于交流、取长补短；重视口试中非语言因素的作用等方面提出一些口试备考技巧。     

矿浆电解法浸出多金属硫化矿中银的工艺条件探讨

在研究矿浆电解法浸出广西某大型含银多金属硫化矿中银的浸出速率变化规律基础上,根据国内外文献资料,总结出银的浸出率与矿粉中银的赋存形式的关系。银在银黝铜矿和在难分解的黄铁矿中的分配率是决定矿粉磨细粒径、电解面积电流、电解时间的最重要因素.在分配率很低时,可采取低电流密度电解,如100~150 A/m2,银的浸出率≥95%;在分配率较高时,采用低电流密度电解,因银黝铜矿及黄铁矿中的银难以浸出,所以银浸出率较低;在分配率小于≤10%时,可采用中等电流密度300~400 A/m2,同时矿粉的磨细程度要保证银矿物晶体部分或全部暴露在黄铁矿晶粒表面,适当增加电解时间,银的浸出率可超过90%.     

Natural frequencies of a flat viaduct road part simply supported on two ends

Viaduct roads have wide application in big cities with high traffic loads, in order to decrease traffic density and to connect subways to highways. Viaduct roads are constructed using steel structures instead of concrete ones in areas of earthquake risks. The low weight of steel structures however causes problems such as vibration and noise. There is increasing demand especially in populated areas to suppress vibration and noise on highway roads for reducing noise-related environmental pollution. In this study, bending vibrations of rectangular plate viaduct roads, which are supported by six fixed elements of rectangular cross-sectional elements are considered. Natural frequencies are obtained using the Rayleigh-Ritz technique, finite elements analysis, experimentally and neural networks (NN).     

多晶FeS2薄膜电学性能的研究与进展

FeS2薄膜是极具研究价值的光电转换材料，改善光电转换效率是主要研究方向，而进一步阐明电传导规律和机制是探索改善FeS2薄膜光电转换效率有效途径的前提之一。本文概述了FeS2薄膜电学性能的研究进展，分析了硫化制备工艺及掺杂效应对FeS2薄膜电学性能的影响，介绍了晶界势垒模型、跳跃传导模型及晶体点缺陷理论等FeS2薄膜电传导相关机制，讨论了FeS2薄膜存在的问题及发展方向。     

Effects of Y concentration on luminescence properties of PbWO4 single crystals

The effects of Y³⁺ doping at different concentration on the luminescnece properties of PbWO₄ crystals have been investigated by means of Fourier transform infrared (FT-IR) spectrum, optical transmission, thermoluminescence (TL), X-ray excited luminescence (XEL), photoluminescence (PL) under excitation of UV light and light yield measurements. The series PbWO₄:Y crystal samples were grown by modified Bridgman method and the concentration of Y³⁺ in the melt was in the range of 0–1.0 mol%. The slight blue-shift and evident red-shift of the absorption edge in PbWO₄ crystal were observed at low and heavy doping concentration, respectively. TL peaks in the range of from room temperature to 250 °C disappeared after the doping with Y³⁺. With the increase of doping concentration, the luminescence intensity in the XEL and PL spectra was found to decrease accordingly, especially in the case of heavy doping. The measuring results demonstrate that Y³⁺ doping concentration below 100 ppm in the crystal seems to be the best for optimizing the optical and scintillation properties of the material. The mechanism of Y³⁺ doping concentration influence on luminescence was also discussed in this paper.     

Obtaining mode mixity for a bimaterial interface crack using the virtual crack closure technique

We review, unify and extend work pertaining to evaluating mode mixity of interfacial fracture utilizing the virtual crack closure technique (VCCT). From the VCCT, components of the strain energy release rate (SERR) are obtained using the forces and displacements near the crack tip corresponding to the opening and sliding contributions. Unfortunately, these components depend on the crack extension size, Δ, used in the VCCT. It follows that a mode mixity based upon these components also will depend on the crack extension size. However, the components of the strain energy release rate can be used for determining the complex stress intensity factors (SIFs) and the associated mode mixity. In this study, we show that several—seemingly different—suggested methods presented in the literature used to obtain mode mixity based on the stress intensity factors are indeed identical. We also present an alternative, simpler quadratic equation to this end. Moreover, a Δ-independent strain energy release based mode mixity can be defined by introducing a “normalizing length parameter.” We show that when the reference length (used for the SIF-based mode mixity) and the normalizing length (used for Δ-independent SERR-based mode mixity) are equal, the two mode mixities are only shifted by a phase angle, depending on the bimaterial parameter ε.