含Cl^-溶液中SO4^2-对316不锈钢临界点蚀温度的影响

采用外加恒电位下腐蚀电流-温度扫描方法研究了在0．5％Cl^-溶液中，SO4^2-浓度对316不锈钢点腐蚀行为的影响．结果表明，随着SO4^2-浓度的增加，钝化电流增加，开路电位降低．当SO4^2-浓度低于0．42％时，316不锈钢的临界点蚀温度比不存在SO4^2-时的临界点蚀温度低；当SO4^2-浓度大于0．42％时，临界点蚀温度比不存在SO4^2-时的临界点蚀温度高．从离子竞争吸附的角度进行分析，对SO4^2-加速与抑制点蚀两种作用规律的形成原因进行了解释．     

压铸机偶发故障期可靠性管理及应用

机器工作可靠度与机器的固有可靠度和使用可靠度密切相关。设备使用厂家通过对机器偶发故障期使用可靠度的研究，采取有效对策来保证和提高机器工作可靠度，是提高企业效益的途径之一。本文针对压铸机，进行了故障规律分析，介绍了偶发故障期可靠度的计量公式，提供了各故障期的经验数据，详述了应用可靠性技术的基础工作范围和内容，叙述了应用效果     

Assessing the effects of gamification in the classroom: A longitudinal study on intrinsic motivation,social comparison,satisfaction, effort,and academic performance

Gamification, the application of game elements to non-game settings, continues to grow in popularity as a method to increase student engagement in the classroom. We tested students across two courses, measuring their motivation, social comparison, effort, satisfaction, learner empowerment, and academic performance at four points during a 16-week semester. One course received a gamified curriculum, featuring a leaderboard and badges, whereas the other course received the same curriculum without the gamified elements. Our results found that students in the gamified course showed less motivation, satisfaction, and empowerment over time than those in the non-gamified class. The effect of course type on students' final exam scores was mediated by students' levels of intrinsic motivation, with students in the gamified course showing less motivation and lower final exam scores than the non-gamified class. This suggests that some care should be taken when applying certain gamification mechanics to educational settings.     

机器视觉在水稻空壳率统计中的应用研究

针对水稻空壳率的自动化检测问题,采用机器视觉技术,设计一种实验设备,利用稻谷的透光性,使用普通可见光照射,对获得的图像进行分析处理,并比较采用灰度特征以及YUV颜色模型两种方法进行统计的结果,表明该设备和相关图像处理算法完全可以胜任空壳率的自动统计工作,为后续发展实际的应用设备奠定基础。     

在嵌入式系统中实现热备份

在要求高可靠性的系统设计中要求系统能够实现双机热备份,从而保证在出现问题时能够快速恢复服务。详细解读了在开发的调度机中如何实现热备份。     

西门子数字输入中断模块的应用研究

介绍了如何在STEP7中配置西门子数字输入中断模块,如何进行软件中断处理,对中断标志位识别和常见编程处理给出了详细的描述.     

Mediating Power: Distance Learning Interfaces, Classroom Epistemology, and the Gaze

Distance learning's interfaces—from corresponding through the postal service to the televised talking head—have traditionally been designed from the top down, supporting banking models of learning or, in writing instruction, current-traditional rhetoric pedagogies. Due to temporal and spatial constraints, these interface designs often support (or encourage) one-way communication from the instructor to the student. Students mostly interact with the instructor by asking questions or submitting work, and they tend to have little correspondence with other peers. These methods clearly privilege the instructor's knowledge and evaluation. Furthermore, these interface designs empower the instructor to gaze upon the students and assess them—often not as a corporeal body but as a corpus of texts. Thus, each interface adopted for distance learning sets up a power dynamic in which the capability to share the roles of creating knowledge is juxtaposed with the instructor's capability to normalize the students and reify their own authority through their gaze. In this article we examine the traditional classroom interface through the correspondence course interface, the simulated classroom interface, and the synchronous video interface to raise questions about the infrastructures of distance learning and their implications for student learning.     

Error compensation in machine tools: a neural network approach

For a non-idealized machine tool, each point in the workspace is associated with a tool point positioning error vector. If this error map can be determined, then it is possible to substantially improve the positioning performance of the machine by introducing suitable compensation into the control loop. This paper explores the possibility of using an artifical neural network (ANN) to compute this mapping. The training set for the ANN is obtained by mounting a physical artifact whose dimensions are precisely known in the machine's workspace. The machine, equipped with a touch trigger probe, measures the positions of features on the artifact. The difference between the machine reading and the known dimension is the machine error at that point in the workspace. Using standard modeling techniques, the kinematic error model for a CNC turning center was developed. This model was parameterized by measurement of the parametric error functions using a laser interferometer, electronic levels and a precision square. The kinematic model was then used to simulate the artifact-measuring process and develop the ANN training set. The effect of changing artifact geometry was explored and a machining operation was simulated using the ANN output to provide compensation. The results show that the ANN is capable of learning the error map of a real machine, and that ANN-based compensation can significantly reduce part-dimensional errors.     

PC机多路数据采集接口卡及编程

介绍了以MC14433为A／D转换器,与IBM－PC总线实现接口的数据采集卡,并通过CD4051多选一开关实现多路输入。文中给出了硬件电路和采样驱动程序流程图。     

矿井主通风机自动监控系统的设计

为了保障主通风机安全、可靠、经济地运行,提出了一种基于S7-300 PLC的矿井主通风机自动监控系统的设计方案;给出了该系统的结构,详细介绍了该系统中PLC的硬件及软件结构、模拟量的检测实现及采用智能型PID调节器XMA5000对风机负压和流量进行自动调节的方法。实际应用表明,该系统能够实现通风机的就地、集中、远方3种控制方式,提高了主通风机的自动化程度和运行可靠性。