关于套拱法技术在拱桥旧桥加固中的应用

本文分析了某拱桥旧桥加固中对套拱法的应用,总结了套拱法技术在拱桥旧桥加固中的技术方案、施工程序和方法。     

基于符号ADD和线性多分支程序的分类算法安全评估

分类算法是机器学习和数据分析中重要的算法.当需要对分类算法本身以及算法的输入数据进行隐私保护时,就出现了分类算法安全评估问题.针对现有的分类算法安全评估协议效率较低的问题,文章给出了一种基于代数决策图和线性多分支程序的解决方案.首先,设计了基于代数决策图的安全函数评估协议,用以安全评估决策函数;其次,引入了线性多分支程序的概念,用其对分类算法进行表示.最后,借助线性多分支程序和基于代数决策图的安全函数评估协议,给出了一个私有线性多分支程序的安全评估协议.对新的协议的正确性和安全性进行了分析和证明.实验数据表明,与原有的解决方案相比,新的协议在效率上有明显的提高.     

基于WinDriver的多路串行设备驱动开发

工业控制计算机中广泛使用串行接口UART与外围设备进行通信,同时,Windows操作系统以其友好的UI界面被广泛采用。文中阐述了UART设备的工作原理,并利用Jungo公司的WinDriver软件实现了Windows操作系统下一种PCI转多路UART设备的驱动开发。     

Evaluating the effectiveness of a post-license education program for young novice drivers in Belgium

The disproportionately large number of traffic accidents of young novice drivers highlights the need for an effective driver education program. The Goals for Driving Education (GDE) matrix shows that driver education must target both lower and higher levels of driver competences. Research has indicated that current education programs do not emphasize enough the higher levels, for example awareness and insight. This has raised the importance of insight programs. On the Road (OtR), a Flemish post-license driver education program, is such an insight program that aims to target these higher levels. The program focus is on risky driving behavior like speeding and drink driving. In addition, the program addresses risk detection and risk-related knowledge. The goal of the study was to do an effect evaluation of this insight program at immediate post-test and 2 months follow-up. In addition, the study aimed to generalize the results of this program to comparable programs in order to make usable policy recommendations. A questionnaire based on the Theory of Planned Behavior (TPB) was used in order to measure participants’ safety consciousness of speeding and drink driving. Moreover, we focused on risk detection and risk-related knowledge. Participants (N = 366) were randomly assigned to a baseline—follow-up group or a post-test—follow-up group.     

多通道光纤传感器解调电路及软件的设计

介绍一种多通道光纤传感器解调电路的方案,并给出了部分核心电路的设计以及主要程序。该电路以8051F为主控芯片,电路设计简单,成本低。通过实际测试,能满足现场要求。     

基于二阶滑移边界的螺旋槽干气密封气膜刚度计算与分析

应用二阶非线性滑移边界条件推导出修正的广义雷诺方程,并用PH线性化方法、迭代法对非线性雷诺方程近似求解,得到气膜推力的近似解析式,继而对其进行气膜厚度的求导,得到气膜刚度的近似解析式.并利用Maple程序计算不同转速和压力下的气膜刚度数值,并与一阶线性滑移边界条件下的气膜刚度和试验数值进行对比.结果表明:随着气膜厚度的增加,二阶非线性滑移边界条件下的气膜刚度随之减小,且呈非线性关系:随着介质压力、转速的增加,气膜刚度也随之增加,且呈线性关系;二阶非线性滑移边界条件下的气膜刚度数值比一阶线性滑移边界条件下的气膜刚度数值更接近试验数值,其计算精度较高,特别是在低速、低压工况下更加明显.因此在低速低压釜用轴端干气密封中将应用二阶速度滑移条件下的流体力学理论来进行优化设计,指导工程应用.     

文学本科专业规模大发展的原因与代价

1993年以来,中国高校的文学本科专业实现了规模大发展。高等教育大众化,专业建设的规模效益,女性的高等教育入学率提高,存量决定增量的发展模式,是文学本科专业规模大发展的主要原因。教育质量滑坡,毕业生就业问题凸显,专业结构调整的难度加大,是文学本科专业规模大发展的主要代价。为防止以上代价的扩大化,当务之急是严格控制文学本科专业的规模增长和学科分化。     

带抛物线轮廓电极的铣削程序编制

利用数控系统的用户宏程序功能编制模具电极的抛物线轮廓加工程序,便于使用不同规格的刀具加工和修改磨损补偿值,提高了单件生产效率和产品加工精度,对编制其他非圆二次曲线轮廓加工程序具有借鉴作用。     

Influence of tooth modifications on tooth contact in face-hobbed spiral bevel gears

In this study the influence of tooth modifications induced by machine tool setting and head-cutter profile variations on tooth contact characteristics in face-hobbed spiral bevel gears is investigated. The concept of face-hobbed spiral bevel gear generation by an imaginary generating crown gear is applied. The modifications of tooth surfaces are introduced into the teeth of both members. The lengthwise crowning of teeth is achieved by applying a slightly bigger radius of lengthwise tooth flank curvature of the crown gear generating the concave side of pinion/gear tooth-surfaces, and by the variation of machine tool settings in the generation of pinion/gear teeth. The ease-off in the tooth height direction of meshing tooth surfaces is achieved by applying a head-cutter whose profile consists of two circular arcs, instead of a straight-line. The method of tooth contact analysis applied determines the path of contact, the potential contact lines, the separations along these lines, and the transmission errors. A computer program implements the method. By using this program the influence of the variation of machine tool settings and of head-cutter geometry on tooth contact is investigated and discussed.     

基于宏程序的多头蜗杆数控加工研究

针对多头蜗杆在加工中,存在切削力过大,刀具磨损严重,对操作技术人员要求较高,而且加工质量难以保证等一系列问题。通过对螺纹车刀刀具的几何角度、蜗杆加工时的切削方法以及切削用量的选择进行了系统分析和优化设计,充分发挥数控机床的功能参数特点,将数控切削中普通螺纹加工的循环指令与制造工艺技术灵活运用,开发出适用于大螺距的各种类型的特殊螺纹加工方法的宏程序,极大地拓展了数控机床的加工范围,实现了数控机床的二次开发。