Synthesis of Ti2SnC from Ti/Sn/TiC powder mixtures by pressureless sintering technique

Ti/Sn/TiC powder mixtures were first employed to synthesize Ti₂SnC powder by pressureless sintering in the temperature range of 950–1250 °C at vacuum atmosphere. Ti₂SnC began to form at 950 °C, its content increased with increasing temperature. High purity of Ti₂SnC was obtained by sintering the mixtures with deficient Sn and TiC at 1200 °C for 15 min. A reaction mechanism was proposed to explain the formation of Ti₂SnC. The Ti₂SnC powder was characterized by scan electron microscopy (SEM) and X-ray diffraction (XRD). Using the above mixtures and process, the Ti₂SnC ceramic powder can be obtained on a larger scale.     

用于参数曲线自由变形的一种新的缩放因子

提出一种用于参数曲线自由变形的新的缩放因子，用该因子此去作用（缩放）待变形曲线，从而使曲线发生形变。通过交互改变控制参数，可达到预期的变形效果。实验表明，这种方法数学背景简单，易于控制，重复使用可获得丰富的变形效果，适用于几何造型、计算机动画等领域。     

神经网络在蒸养粉煤灰砖抗压强度预测中的应用

首先简要阐述蒸养粉煤灰砖的生产流程,然后通过建立BP神经网络模型来预测粉煤灰砖的抗压强度值,仿真结果表明此模型用于强度预测是可行的。     

基于通用USB接口的软件加密狗设计

USB接口已逐渐成为计算机上最常用的接口之一,基于USB接口的软件加密狗相对于并口或串口的软件加密狗将具有更强的通用性。同时,由于USB接口的热插拔特性,用户使用时更加便捷。本文主要讨论了基于单片机扩展USB接口设计软件加密狗的方法,给出了硬件原理图并介绍了固件程序、设备驱动、RC5加密算法的编制过程。     

入侵检测技术研究

论文介绍了入侵检测技术的概念,分类和通用入侵检测框架,详细分析了各种入侵检测技术。并对入侵检测技术的未来发展方向进行了探讨。     

Optimum Design of Welded Steel Plate Girder Bridges Using a Genetic Algorithm with Elitism

The genetic algorithm (GA) is a general optimization technique that has some unique features that are especially suitable for structural engineering problems. This work uses a simple GA with elitism to find the optimum design of welded steel plate girder bridges. The objectives are to minimize the weight and the cost of the girders. Two types of plate-girder bridges are studied: a single-span bridge and a two-equal-span continuous bridge. Bridges with various span lengths, in increments of 20?ft, are investigated; results are tabulated, parametric studies are made, and meaningful conclusions are drawn.     

用Monte Carlo法模拟矿热炉炉料的导电行为

介绍了Monte Carh，法模拟矿热炉炉料导电行为的初步研究。模拟结果表明，模拟炉料中，矿石粒径一定，随焦炭粒径增大，形成逾渗结构的临界值Φc（导电相体积分数）增大；在临界点以上，炉料导电性与导电相——焦炭含量的关系近似于对数关系。纯焦炭颗粒直径对其电阻影响的模拟结果与冷态实验结果不符，说明该数学模型在模拟炉料电阻变化方面尚需要改进。     

石英晶体薄膜厚度差动测量技术的研究􀀁

本文介绍一种石英晶体膜测厚的差动工作方式。它的厚度测量精度为１ｎｍ，分辨率为纳米级，其温度稳定性在０－＋４００℃范围内达到５０Ｈｚ。这种差动测量技术不仅可在真空镀膜工艺中实现在线测量，而且在纳米技术及超精细加工中具有广阔应用前景。     

三相异步电动机起动方式的分析与选择

通过分析三相异步电动机各种起动方式的电压、电流、转矩的波形和特性,合理选择合适的起动方式。     

浅析TSC+ASVG混合型动态无功补偿系统

本文阐述了TSC ASVG混合型动态无功补偿系统的组成和工作原理。它是一种新型的．先进的动态无功补偿系统。在电网治理中具有很好的适用性和良好的性能。