Effects of liquid phases on densification of TiO2-doped Al2O3–ZrO2 composite ceramics

This study investigated the densification behaviors and microstructural evolution of Al₂O₃–ZrO₂ (3Y) composite ceramics doped with four different amounts of TiO₂ (0, 1, 4, and 8 wt%; denoted as 0T, 1T, 4T, and 8T, respectively) to clarify the effect of TiO₂ dopants on densification. The shrinkage rate during densification increased with the increase in the amount of TiO₂. The development of grain boundary feature was also examined. The undoped ceramic showed clean grain boundaries. Thin liquid grain boundary phases were observed in 1T, whereas large liquid phases were found on the grain boundary and at the junction pockets in 4T and 8T. The results were discussed in terms of the relationship between densification and grain boundary feature.     

以就业为导向的药学多元化实践基地的探讨

探讨以社会求与学生就业意愿有机结合为导向的药学多元化实践基地建设思想,通过建设以学生生源地为依据的广西各地市三甲医院、药检所、制药企业等实习基地,方便学生学习及就业。建立"双模块双导师制"实践模式,强化岗前思想道德教育和技能训练,培养适合社会求的新型药学应用型人才。     

大功率履带推土机的差速转向技术

对大功率推土机的差速转向技术做了介绍,并对该机构的组成、工作原理及使用特点进行了讨论分析。     

晶振芯片在高g值冲击下的失效机理分析

芯片是弹载存储测试系统的最基本的单元,它的抗强冲击能力直接影响测试系统的可靠性.为了研究芯片抗高过载能力,本实验利用Hopkinson杆对最典型的晶振芯片进行高g值冲击,以一维应力波理论估计芯片受到的加速度.对实验现象进行理论分析后得出与应力波传播方向平行放置的芯片抗冲击性能要高于与应力波传播方向垂直的芯片.     

用于火炮膛内压力测试的电容式传感器的设计

通过研究目前火炮膛压测试中所存在的问题--传感器安装结构与测压器小体积之间的矛盾,设计了一种新的用于火炮膛压测试的电容式压力传感器,由电路筒作为固定电极,测压器壳体作为可动电极形成极间距离为0.5 mm的同轴圆筒电容变换器,它的固有频率达到52.665 kHz,灵敏度为0.009 9 pF/MPa,压力测量范围是0-600 MPa,论文详细阐述了电容式压力传感器的工作原理,结构设计,利用有限元软件ANASYS对其力学特性及热学特性进行了仿真模拟,并做了性能测试.试验结果表明:电容值和所受压力近似成线性关系,且具有良好的稳定性.     

Dynamic calibration method of high-pressure transducer based on quasi-δ function excitation source

This paper presents a dynamic calibration method of frequency response characteristics of high-pressure sensor. In this method, the pressure sensor was under high hydrostatic pressure in advance, then use the bullet impacted Hopkinson bar and generated quasi-δ function signal with small amplitude, which excited the sensor being calibrated. The excitation signal of sensor are collected, at the same time, output signal of the sensor are collected, and at last, the collected data are processed according to calibration principle and calculated the frequency response of the sensor being calibrated. This calibration method realized dynamic calibration of high pressure sensor under actual working pressure; it can realize the low limit frequency of the calibrated frequency range strictly reaches to zero frequency. This method can also be applied to acceleration sensor, transient high-temperature sensor, and other types of sensors. In this paper, the calibration principle of quasi-δ function dynamic calibration method is introduced. The relationship among pulse width of excitation signal, frequency range that can be calibrated and calibration precision is analyzed. The experimental results are also shown.     

基于神经网络的材料性能参数和摩擦系数的实时识别

在板材拉深成形智能化控制过程中 ,为了避免缺陷的产生 ,必须适时地改变控制工艺参数 ,而最佳控制参数要根据材料的性能参数和摩擦系数来预测。根据拉深成形过程的特点及生产过程中自动化程度的要求 ,建立了材料性能参数和摩擦系数识别的人工神经网络模型。利用神经网络这种新一代信息处理工具实现了材料性能参数和摩擦系数的实时识别 ,为实现板材拉深成形过程的智能化控制奠定了基础     

双辊薄带连铸技术的研究与发展

双辊连铸技术是一种新型近终形连铸技术,近年来受到普遍关注。本文综述了该项技术在国内外的研究与发展,介绍了侧封、轧辊运行状况和工艺参数等双辊连铸技术中的关键问题及研究热点。双辊连铸技术将广泛应用于不铸钢薄带的连续铸造生产、其它高合金特种钢双辊连铸技术的研究与应用也指日可待。     

Assembly of Single-Stranded DNA Onto HOPG Surface at Different Temperature: Atomic Force Microscopy Study

Assembly of long single‐stranded DNA (ssDNA) and short oligodeoxynucleotides onto bare highly oriented pyrolytic graphite (HOPG) at different temperature has been studied. It was indicated that both long ssDNA and oligodeoxynucleotides can sequentially form network, straight chains, and layer structures when the adsorption temperature was changed from room temperature, 37–55°C. High‐resolution atomic force microscopy (AFM) imaging of the layer structures revealed that they are composed of parallel ssDNA chains with relatively higher height and tend to form patterns with three‐fold symmetry. These new findings are significantly important for understanding assembly characterization of ssDNA. In addition, this assembly method for ssDNA is expected to be used for preparation of DNA structures in biosensing and DNA‐based nanodevices. SCANNING 34: 302–308, 2012. © 2012 Wiley Periodicals, Inc.