浅谈本科教学工作水平评估与高校师资队伍建设

本科教学工作水平评估是提高高校教学质量的重要手段,也是对高校教师队伍整体素质的大检阅。目前高校师资队伍建设状况还不能达到评估的要求。为此,各高校可根据评估指标体系要求,加强师资队伍建设,从而提高学校的教育教学质量。     

制约我国风险投资发展的因素分析

风险投资是促进高新技术产业发展的重要手段,发展风险投资也是一项复杂的系统工程,要涉及诸多方面的因素。文章首先介绍一下什么是风险投资,进而从我国现今风险投资发展角度以及存在的问题对制约我国风险投资业发展的问题进行了简要分析。     

包埋时间对N80套管钢表面渗铝层组织和性能的影响

为提高套管钢的耐腐蚀性能,在950℃对N80套管钢分别进行了2 h、4 h及6 h的包埋渗铝工艺处理.不同包埋时间下所得渗层的物相组成、微观形貌、显微硬度和电化学性能不同.测试结果表明:渗铝时间为2 h时,所得渗铝层厚度为150μm,渗铝时间延长到4 h和6 h后,渗铝层厚度增大到300μm;渗铝时间为2 h、4 h时所得N80套管钢的渗铝层主要由FeAl金属间化合物组成,当渗铝时间为6 h时,渗铝层中开始出现了高铝Fe2Al5相;不同时间包埋渗铝处理后的N80套管钢试样表面硬度高于基体,自腐蚀电流密度显著下降.由此得出结论:高铝相铁铝化合物随包埋时间的延长开始出现;渗铝层厚度随包埋时间的延长有所增加,当包埋时间超过4 h后,包埋时间对渗铝层致密度的提高作用较厚度增加更为显著;延长包埋时间可以显著提高渗铝层的硬度,但过长的包埋时间会同时造成基体硬度严重地下降;包埋时间对腐蚀性能的影响作用不明显.     

A novel low-loss four-bit bandpass filter using RF MEMS switches

This paper details the design and simulation of a novel low-loss four-bit reconfigurable bandpass filter that integrates microelectromechanical system(MEMS)switches and comb resonators.A T-shaped reconfigurable resonator is reconfigured in a'one resonator,multiple MEMS switches'configuration and used to gate the load capacitances of comb resonators so that a multiple-frequency filtering function is realized within the 7-16 GHz frequency range.In addition,the insertion loss of the filter is less than 1.99 dB,the out-of-band rejection is more than 18.30 dB,and the group delay is less than 0.25 ns.On the other hand,the size of this novel filter is only 4.4 mm×2.5 mm×0.4 mm.Our results indicate that this MEMS reconfigurable filter,which can switch 16 central frequency bands through eight switches,achieves a low insertion loss compared to those of traditional MEMS filters.In addition,the advantages of small size are obtained while achieving high integration.     

Fabrication and investigation of ferroelectric memristors with various synaptic plasticities

In the post-Moore era, neuromorphic computing has been mainly focused on breaking the von Neumann bottlenecks. Memristors have been proposed as a key part of neuromorphic computing architectures, and can be used to emulate the synaptic plasticities of the human brain. Ferroelectric memristors represent a breakthrough for memristive devices on account of their reliable nonvolatile storage, low write/read latency and tunable conductive states. However, among the reported ferroelectric memristors, the mechanisms of resistive switching are still under debate. In addition, there needs to be more research on emulation of the brain synapses using ferroelectric memristors. Herein, Cu/PbZr_0.52Ti_0.48O₃ (PZT)/Pt ferroelectric memristors have been fabricated. The devices are able to realize the transformation from threshold switching behavior to resistive switching behavior. The synaptic plasticities, including excitatory post-synaptic current, paired-pulse facilitation, paired-pulse depression and spike time-dependent plasticity, have been mimicked by the PZT devices. Furthermore, the mechanisms of PZT devices have been investigated by first-principles calculations based on the interface barrier and conductive filament models. This work may contribute to the application of ferroelectric memristors in neuromorphic computing systems.     

基于微孔板化学发光法检测碱性磷酸酶的研究

CDP-Star能被ALP迅速水解,且水解产物能够持续发光.本研究对化学发光法检测ALP的反应条件进行了优化.优化后的反应条件为:125 μtmol/L的CDP- Star在pH 9.5缓冲液中,37℃下与ALP反应10min.在此条件下,△RLU与ALP的活力呈线性关系.因此,建立了一种基于微孔板化学发光法检测ALP的实验方法.结果表明,本方法检测ALP的检测线性范围是0.05～10 U/L和10～1000 U/L,相对于光吸收法具有速度快、灵敏度高、重复性好等优点.因此,本方法可以被开发成试剂盒,应用于高通量全自动生化分析仪的测试分析.     

专家-新手教师化学课堂教学对话特征的比较研究

采用专家-新手比较研究方法,对专家教师和新手教师化学课堂教学对话的内容和方式进行了比较。结果表明,专家教师的课堂对话属于“以问题为中心的互动式对话”,具体特征表现为“教师提问-学生陈述-师生质疑-共同评价”;而新手教师的课堂对话属于“以教师为中心的问答式对话”,具体特征表现为“教师提问-学生回答-教师评价”。     

多晶纯钛在高应变率不同温度下的拉伸力学行为实验研究

利用MTS809和自行研制的旋转盘冲击拉伸试验机,对多晶纯钛进行了应变率为0.001s-1和300s-1、温度为298K至973K的拉伸试验和应变率为300 s-1不同温度下的冲击拉伸复元试验,得到了多晶纯钛的拉伸应力应变曲线和高应变率等温应力应变曲线。试验结果表明,多晶纯钛的拉伸力学行为具有应变率和温度相关性。采用修正的Johnson-Cook模型进行数值拟合,结果表明,该本构模型能较好地表征多晶纯钛在试验应变率和温度范围内的拉伸力学行为。     

水利工程桩支承式沉井技术探讨

沉井是修建深基础和地下深构筑物的主要基础类型,广泛地应用于工程实践,如桥梁、水闸、港口等工程中用于基础工程。桩支承式沉井有效地预防了在软土地基中极易产生超沉、偏倾等施工难题,在工程实践中收到了较为满意的效果,值得深入研究。     

基于手机模块的车载服务系统设计

介绍了一种基于手机模块的新型车裁服务系统.该系统以MSP430单片机为核心,利用GSM模块进行远程无线通信,采用了GPS、红外遥控和液晶显示等技术,实现了车辆卫星定位、短信息的收发、车载电话以及车辆监控等功能.