A new liquid crystal lens with axis-tunability via three sector electrodes

A novel liquid crystal (LC) lens with an on-line tunability on focus length and optical axis is proposed in this study. The designed lens has a LC layer sandwiched by two ITO glasses, one of which is patterned with three sector electrodes. With varied sets of pre-designed voltages applied to these three electrodes, the LC lens can not only render focusing effects but also tunability on the optical axis of the lens to an arbitrary axis. A vector-form equation is developed to predict the direction of axis tuning. Simulations are next conducted to predict dynamics of the LCs in the lens and also the focusing and axis-tuning properties of the lens. Important sizes and materials and fabrication process of the lens are determined and optimized based on simulation results. The designed LC lens is fabricated, and then experiments are conducted to demonstrate the performance of the designed LC lens on axis tuning. It shows that the focusing axis of the LC lens can be effectively changed by pre-calculated combinations of three voltages. It is also shown that the average movement of the focal point per applied voltage reaches 4.778?μm/V.     

校园卡管理信息系统的设计与实现

本文分析了校园卡管理信息系统的功能需求,对系统功能模块设计、数据库的设计与实现以及后台信息管理模块的设计与实现,进行了详细的介绍。     

带有时间窗的虚拟场站接驳补货车辆路径问题

针对大区域多需求点的物流配送系统,在原有的车辆配送总费用为目标的基础上,兼顾顾客的满意度目标,建立了带有时间窗车辆路径问题的多目标最优化模型,该模型基于大小车沿途在虚拟场站接驳补货策略,节省了货车往返配送中心补货次数、距离与时间.根据该模型需要部分顾客作补货点的特点,利用K均值聚类的方法将顾客分类,采用基于分区域和极大极小策略的多目标进化算法思想进行求解,以测试题库The VRP Web中的算例进行测试分析.经由测试结果比较,相较于非接驳补货的传统VRPTW,该模型效益明显.     

Tribological performance of TiAlSiN and TiAlCrN/TiAlN coating blades

A new laboratory evaluation method for the coating blade was developed, and the tribological properties of coating blades with different Ti-based coatings were studied by UMT-2 tribometer. Comparison between the areas of scratches before and after the cutting experiment was used to evaluate the cutting performance of the blades. Results showed that friction coefficient of TiAlCrN / TiAlN coating was significantly lower than that of TiAlSiN coating. Analysis of the worn surface revealed that the TiAlSiN and TiAlCrN / TiAlN coatings in the dry turning process exhibited sign of inhomogeneous adhesive wear and abrasive wear. TiAlCrN/TiAlN coating has a longer working life and better anti-wear property because of its duplex coating.     

基于可拓理论的网络安全评估研究

针对目前网络安全评估算法存在的不足,提出了一种基于可拓模糊层次分析的安全评估算法。该算法在模糊层次分析法的基础上,结合可拓理论,将调查问卷表收集到的指标值映射到可拓区间中,通过相对隶属度的计算,构建了新的判决矩阵,利用模糊层次分析法计算各指标的综合权重。通过对相对隶属度的加权排序,得到网络安全评估值。通过实例分析,说明该方法能综合考虑专家打分的权威性和调查问卷的普遍性,提高了网络安全评估的准确性和有效性。     

PEG分子量对PET—PEG共聚酯结晶性能的影响

通过ＰＥＴ和ＰＥＧ共缩聚，合成了ＰＥＴ—ＰＥＧ共聚酯，采用ＤＳＣ、等温结晶仪、Ｘ衍射分析仪和电子扫描电镜研究了ＰＥＧ分子量对该共聚酯结晶性能的影响。结果表明，在ＰＥＴ分子结构中引入ＰＥＧ链段，能有效提高结晶速度，共聚酯结晶结构与ＰＥＴ类似，但ＰＥＧ不进入晶格中，只起诱导结晶的作用。当ＰＥＧ分子量为４０００时，冷结晶温度Ｔｃｃ降得最低，但热结晶温度Ｔｃ反而比纯ＰＥＴ有所增加，１１０℃结晶速度ｔ１２＝１ｍｉｎ，而纯ＰＥＴ需１２ｍｉｎ。     

Ni implantation-induced enhancement of the crystallisation of amorphous Si

We report on the effect of Ni implantation on the crystallisation process of amorphous Si formed by ion implantation during excimer laser annealing. Scanning transmission electron microscopy and X-ray photoemission spectroscopy results show that NiSi₂ precipitates are formed in the Si–Ni-implanted samples. It is shown that the Ni implantation results in the enhanced crystallisation of amorphous Si during laser annealing. The Si–Ni-implanted samples become epitaxial to the Si substrate at 600 mJ/cm², while the Si-implanted samples produce epitaxial relationship at 800 mJ/cm². Possible mechanisms by which implanted Ni atoms play a role are given to describe the enhanced crystallisation process of amorphous Si.     

基于Internet的空分设备远程监视与故障诊断专家系统的研究

简介了远程监视与故障诊断专家系统在国内空分设备中应用的实际意义，着重分析了大型空分设备远程监视与故障诊断专家系统中远程监视模块和故障诊断模块的开发。     

远动下行通道中断自动报警的实现

介绍了一种电力系统远动下行通道自动监视、报警的原理及硬件实现方法,并计算了相关元件的参数,该种方法已在生产实践中得到验证,能够解决下行通道中断后的自动语音报警、状态实时显示等功能。     

A differential pulsewidth control loop for high-speed VLSI systems

For those adopting double data rate technology systems, the precise system timing plays a crucial role since both rising and falling edges of the system clock signal are used to sample the input data. Due to this requirement, it is necessary to accurately maintain the duty cycle of the clock signal at 50%. For a multistage clock buffer, a pulsewidth control loop (PWCL) circuit was therefore proposed to adjust the duty cycle of its output signal. This paper is aimed at introducing a new proposed differential PWCL (DPWCL) together with investigating its mechanism through a comprehensive theoretical analysis. By taking advantage of a differential topology, the dc offset in generating the control voltage can be removed thereby improving the duty cycle control accuracy. Moreover, the proposed DPWCL employs a low-pass filter to generate the reference voltage so that the DPWCL does not necessitate a 50% duty cycle reference clock.