基于氧化石墨烯的ST-cut声表面波高性能湿度传感器

开发了氧化石墨烯(GO)涂覆的ST-cut石英声表面波(SAW)湿度传感器。SEM和FTIR研究发现GO表面呈现起伏褶皱状且含有亲水性基团,这有利于薄膜对水分子的吸附;还发现SAW湿度传感器的频移响应由质量负载效应提供,且高湿度下传感器频移的指数增加归因于水凝结引起的阻尼效应。该传感器具有良好的灵敏度、几乎为零的温度系数、稳定的短期重复性与长期稳定性,且成本低,为湿度传感的研究提供了较好的选择。     

Preparation of AlN thin films for film bulk acoustic resonator application by radio frequency sputtering

Aluminum nitride （AlN） thin films with high c-axis orientation have been prepared on a glass substrate with an Al bottom electrode by radio frequency （RF） reactive magnetron sputtering. Based on the analysis of Berg＇s hysteresis model, the improved sputtering system is realized without a hysteresis effect. A new control method for rapidly depositing highly c-axis oriented AlN thin films is proposed. The N2 concentration could be controlled by observing the changes in cathode voltage, to realize the optimum processing condition where the target could be fixed stably in the transition region, and both stoichiometric film composition and a high deposition rate could be obtained. Under a 500 W RF power of a target with a 6 cm diameter, a substrate temperature of 450 ℃, a target-substrate distance of 60 mm and a N2 concentration of 25%, AlN thin film with preferential （002） orientation was deposited at 2.3 μm/h which is a much higher rate than previously achieved. Through X-ray diffraction （XRD） analysis, the full width at half maximum （FWHM） of AlN （002） was shown to be about 0.28°, which shows the good crystallinity and crystal orientation of AlN thin film. With other parameters held constant, any increase or decrease in N2 concentration results in an increase in the FWHM of AlN.     

一种可控硅抢答器设计与制作

研制一种以单向可控硅为核心部件,并能灵活控制抢答组数的抢答器系统。从基本原理、系统所用元器件、制作与操作步骤等方面阐述了该控制系统的设计方法。经过调试与操作,该系统运行稳定,能完成基本的抢答功能,达到预期目标,而且制作过程简单、成本较低,实用性较好,省去了单片机的复杂编程程序,并且可以随意增加抢答组数,不影响电路的稳定性。     

Design and application of learning environments based on integrative problems

This work reports on the results obtained from the application of learning environments on the basis of one integrative problem and a series of other smaller problems that limit the contents to be investigated and learned by the students. This methodology, which is a variation to traditional problem-based learning approaches, is here illustrated in terms of its application in an engineering economics course, a subject that is taught in most engineering programs. The purpose of this methodology is to improve students’ learning, which is measured through the students’ academic performance and their learning strategies, and to characterise them as a function of these variables. The results obtained after the systematic application of this methodology are positive. The surveyed students showed significant changes in the examined variables as well as in their satisfaction and motivation level, and in their commitment to learning.     

AlN/蓝宝石衬底上AlGaN-UV-LEDs光学性能改善研究

通过有机金属化学气相沉积法在AlN/蓝宝石衬底上生长AlGaN基多量子阱结构的发光二极管(LEDs),其对应的发光峰值波长为264nm(UV-C区)。通过在活性区域和p型外延层之间插入1nm厚的本征AlN层(起到电子挡层的作用),可以清楚地观测到有效抑制位于320nm附件的寄生发光峰,推测这是电子溢出或Mg扩散所致。此外,发现了通过改变外延层的结构可以使LEDs的输出功率增长20倍以上。     

基于声发射的棒料起裂时间测定教学实验平台开发

为加深学生对现代制造技术和广义切削技术的认识与理解,将机械设计、声发射技术和传感器技术结合起来,研发了基于声发射无损检测棒料起裂时间测定教学实验平台。采用多特征参数关联分析法对下料过程中V型槽尖端起裂声发射信号进行了描述,并用峰态系数对该信号进行进一步处理,定量得到了V型槽槽深为2 mm的45~#钢棒料在低应力下料过程中的起裂时间约为24 s。该实验平台使得金属加工成型过程更加直观,不仅加深了学生对现代制造技术、切削原理与刀具等课程的认识与理解,而且提高了学生对机械加工理论的学习兴趣,达到了良好的实验教学效果。     

基于声波共振的液位测量实验系统设计与测试

设计了基于低频声波共振的液位测量系统。该系统由硬件数据采集装置与软件信息处理模块组成,硬件数据采集装置实现声波信号的发送和接收,软件信息处理模块实时地处理接收到的声波信号。该实验系统涵盖了扫频信号的发生、声波信号的采集、温度数据的采集、共振频率的提取、液位信息的计算及显示,有助于学生对声波的衍射和共振的原理有更加深入的了解,掌握硬件设计以及开发的基本流程,提高学生的软、硬件设计的能力。     

Design of virtual environments for the comprehension of planetary phenomena based on students' ideas

Children enter the classroom with a wide range of misconceptions about planetary phenomena. Conventional teaching methods usually cannot overcome these difficulties, which we consider may be because of the lack of appropriate teaching aids. The purpose of the present study is the design and development of an educational virtual environment for the support of the teaching of planetary phenomena, particularly of the movements of the Earth and Sun, the day and night cycle and the change of seasons. Our interactive three-dimensional (3D) virtual environment was based on the results of an empirical study of 102 secondary school students and provides students with new experiences, personal involvement and close-up examination of the phenomena under study. Our first results after the use of the virtual environment showed that the majority of students enthused about interacting with it and modified their misconceptions concerning the day-night cycle and the change of seasons.     

Research on transmission performance of a surface acoustic wave sensing system used in manufacturing environment monitoring

Surface acoustic wave (SAW) sensors show great promise in monitoring fast-rotating or moving machinery in manufacturing environments, and have several advantages in the measurement of temperature, torque, pressure, and strain because of their passive and wireless capability. However, very few studies have systematically attempted to evaluate the characteristics of SAW sensors in a metal environment and rotating structures, both of which are common in machine tools. Simulation of the influence of the metal using CST software and a series of experiments with an SAW temperature sensor in real environments were designed to investigate the factors that affect transmission performance, including antenna angles, orientations, rotation speeds, and a metallic plate, along with the interrogator antenna–SAW sensor antenna separation distance. Our experimental measurements show that the sensor’s optimal placement in manufacturing environments should take into account all these factors in order to maintain system measurement and data transmission capability. As the first attempt to systematically investigate the transmission characteristics of the SAW sensor used in manufacturing environment, this study aims to guide users of SAW sensor applications and encourage more research in the field of wireless passive SAW sensors in monitoring applications.     

基于PLC与触摸屏的物料分拣教学实验台设计

针对高校实验设备功能单一等问题,设计了一种基于PLC与触摸屏的物料分拣教学实验台。将传感器技术、液压与气动控制、机电传动与控制、MCGSE组态开发、PLC控制技术有机结合在一起,形成一个多功能教学实验平台,可完成传感器技术实验、液压气动实验、机电传动实验、MCGSE组态实验、PLC控制实验以及控制电路实验,保证了教学实验设备的先进性与创新性,提高学生的动手和实践能力。     

基于KeilC51软件的电子钟设计与制作

该文介绍了KeilC51软件作为单片机应用系统设计工具的强大功能,并以单片机为核心实现电子钟的设计为例,阐述如何借助该软件进行单片机应用系统的设计与仿真。     

基于FPGA多功能波形发生器的设计与实现

介绍了一种以FPGA为核心，应用VHDL技术的多功能波形发生器软件和硬件的设计与实现．该系统可以产生正弦波、三角波、方波，以及编辑生成上述3种波形（同周期）的任意波形的线性组合波形，并实现幅度、频率可调．     

基于拓扑优化的二维声屏障吸声材料分布设计

为了改善声屏障的降噪效果,本文采用边界元法和移动渐近线优化算法对声屏障表面吸声材料的分布进行优化设计。基于各向同性惩罚微结构模型法(SIMP)变密度拓扑优化方法,建立以吸声材料单元相对密度为设计变量,以吸声材料的体积为约束,以参考面声压值最低为设计目标的拓扑优化数学模型,使用边界元法进行敏感度计算,最终使用移动渐近线优化算法求解优化模型。以二维声屏障模型为例,对表面吸声材料的分布进行优化设计,验证了所提方法在减噪优化设计中的可行性。算例结果显示:声屏障表面全部敷设吸声材料通常不是降噪效果最佳的情况,这一结果凸显了优化设计的重要性。     

输气管道声波泄漏监测试验装置的设计与构建

设计了一套完整的基于瞬态模型法和声波泄漏检测法的高压输气管线泄漏试验装置.首先通过大量模拟计算,确定了试验装置的各种参数,并对各种仪表进行了选型;分析了声波在管道中的传播规律以及衰减特性,选取了合适的声波传感器,并对试验模型与实际输气管线进行了相似性分析;验证了模型试验的可推广性,然后分析了虚拟仪器的组成,设计了基于虚拟仪器的输气管道泄漏检测数据采集系统.     

谈美术教学CAI课件的设计与制作

多媒体教学是课堂教学中一种崭新的教学模式。本文将对美术CAI课件的设计、制作过程及多媒体制作工具的主要功能做一些探讨     

电波传播模型的教学演示系统设计

利用Matlab GUI平台设计开发了无线电波传播特性的教学演示系统,实现了常见的无线通信环境下电波传播路径损耗的模拟及计算。教学实践表明:该系统操作简单、交互性强,以可视化的界面和图表揭示了复杂公式的物理含义和工程意义,有效地提高了教学效果,提高了学生理论联系实际的能力。     

基于4C/ID模式的《沟通与表达》课程整体设计

4C/ID模式是国际上具有广泛影响的综合性教学设计模式,注重学习的迁移。文章介绍了4C/ID模式在《沟通与表达》课程整体设计中的应用,分析了传统教学模式的问题,明确了"综合学习"的课改方向,基于实践专家调研确定了课程的综合学习任务,并应用简化条件法对学习任务类别进行了梳理和描述,可以为公共课整体设计提供有益借鉴。     

生物转盘水处理实验设备的设计制作

生物转盘水处理实验设备是一种既可应用于教学实验又可应用于科研的实验设备,该文介绍了该实验设备的原理、设计思想、结构特点。运行试验的结果表明,该设备启动容易、操作简便,完全能够满足教学及科研的要求。     

混凝沉淀水处理实验设备设计制作

介绍了混凝沉淀水处理实验设备的设计思想、组成结构、特点。对该设备进行了启动试验，结果表明该设备具有启动容易、完全满足教学及科研的要求。该实验设备是既可应用于教学实验又可应用于科研的一种实验设备。     

玻片表面手臂分子的组装及对寡核苷酸原位合成与杂交的影响

以 3缩水甘油环氧丙基三甲氧基硅烷对玻璃基片表面进行硅烷化后 ,用下列 4种方法组装手臂分子 :①盐酸直接处理 ;②先用聚六乙二醇 ,然后用盐酸处理 ;③用乙二胺、戊二醛、乙醇胺和硼氢化钠分别处理 ;④用聚六乙二醇、乙二胺、戊二醛、乙醇胺和硼氢化钠分别处理 .用XPS(X-ray photoelectron spectroscopy)和测定接触角的方法对上述组装进行了表征 ,并用直接偶联荧光单体及合成 2 0mer寡核苷酸与带荧光的互补探针杂交的方法对上述手臂分子的合成效率及杂交效率进行了考察 .实验表明方法③组装的手臂分子得到的结果优于其他 3种方法 ,证明了手臂分子的空间效应、亲水性等性质对寡核苷酸合成和杂交存在影响 .