A periodically poled LiNbO3 optical parametric generator in wavelength conversion from 2 to 3.88-4.34 μm

A periodically poled lithium niobate (PPLN) optical parametric generator (OPG) pumped by a laser diode (LD)-pumped Q-switched Tm,Ho:GdVO4 laser operated at 2.048 μm with pump pulse of 25 ns and repetition rate of 10 kHz is reported.     

Z2k上的对偶码

利用Z2k-线性码的生成矩阵及检验矩阵,给出了Z2k-线性码为自对偶码的必要条件,并给出了由一个Z2k-线性码构造Z2k-线性码的两种方法。     

An Improved Chua's Circuit and Its Use in Hyperchaotic Circuit

An improved implementation of Chua's circuit using dual output current conveyor is presented. The present proposal offers the advantages of low component count, current mode processing, availability of current across inductor and availability of voltage across inductor in form of current. The application of present circuit in designing low hardware inductorless hyperchaotic circuit is also presented. The paper concludes with a discussion of advantages of present proposal of Chua's circuit and inductorless hyper chaotic circuit thus designed over their earlier counterparts. The designs are adequately supported by SPICE simulation results. Patent pending.     

发电机局部放电非线性模式识别现状及展望

局部放电是导致发电机定子绝缘劣化的重要因素,在线监测局部放电信号并采用非线性方法识别放电类型,能够及时发现绝缘内部局部缺陷及放电发展程度,防止事故发生。阐述了发电机局部放电产生的类型、特点、在线监测方法以及放电过程的非线性特征,介绍了几种非线性模式识别方法的构成原理与特点,包括基于人工神经网络、小波分析和分形理论的局部放电模式识别,并对近年来各非线性识别方法及其组合的主要研究成果进行了总结与评述。最后还对未来发电机局部放电模式识别的研究方向进行了展望,指出快捷方便的非线性识别方法依然是研究的重点。     

图形发生器的成像系统

为实现电子束曝光机扫描场的线性畸变校正,设计了图形发生器的成像系统,该系统包括硬件和软件两部分。硬件设计上使用了高速、高精度模数转换器,并对其工作方式及图像采集流程做了具体阐述。软件设计上利用点阵成像的原理,把采集到的图像信号转变成相应的灰度值,并按点阵排列,将最终获得的图像显示在计算机屏幕上,以实现校正。同时还给出了对图像进行局部放大的方法及计算公式。实验证明,该成像系统工作正常,可以获得清晰的图像。     

“强光一号”等离子体断路开关及负载的数值计算

 等离子体断路开关（POS）是“强光一号”加速器产生短脉冲γ射线的关键器件之一。应用POS融蚀模型分析了“强光一号”加速器POS与二极管系统的基本工作过程，通过该模型计算获得了POS与二极管系统的总电流以及电子束电流，计算结果与实验结果吻合较好。计算结果表明，“强光一号”POS在工作时并未达到完全磁绝缘状态，其阻抗最终为21.5 Ω，约有60％总电流在二极管负载导通时流过POS，且融蚀模型对POS阻抗增长预测偏高，但由于电流变化较大，二极管负载电压仍能达到4.5 MV左右。     

QPECgen, a MATLAB Generator for Mathematical Programs with Quadratic Objectives and Affine Variational Inequality Constraints

We describe a technique for generating a special class, called QPEC, of mathematical programs with equilibrium constraints, MPEC. A QPEC is a quadratic MPEC, that is an optimization problem whose objective function is quadratic, first-level constraints are linear, and second-level (equilibrium) constraints are given by a parametric affine variational inequality or one of its specialisations. The generator, written in MATLAB, allows the user to control different properties of the QPEC and its solution. Options include the proportion of degenerate constraints in both the first and second level, ill-conditioning, convexity of the objective, monotonicity and symmetry of the second-level problem, and so on. We believe these properties may substantially effect efficiency of existing methods for MPEC, and illustrate this numerically by applying several methods to generator test problems. Documentation and relevant codes can be found by visiting http://www.ms.unimelb.edu.au/danny/qpecgendoc.html.     

A monolithic low-power high-voltage driver for bistable LCDs

A complete low-power high-voltage driver for a 80×104 passive-matrix bistable LCD is integrated in a 0.7 μm CMOS smart-power technology. It features 100 V driving capability on all row and column outputs and comprises all necessary digitally programmable high-voltage generators and multiplexers to synthesize the required complex high-voltage waveforms from a 3 V battery. An original level-shifter design for the high-voltage multiplexers and a dedicated architecture for the programmable high-voltage generators yield an extremely low internal power consumption below 10 mW for the entire driver chip.     

Mathematical modeling of a steam generator for sensor fault detection

A dynamic model for a nuclear power plant steam generator (vertical, preheated, U-tube recirculation-type) is formulated as a sixth-order nonlinear system. The model integrates nodal mass and energy balances for the primary water, the U-tube metal and the secondary water and steam. The downcomer flow is determined by a static balance of momentum. The mathematical system is solved using transient input data from the Philippsburg 2 (FRG) nuclear power plant. The results of the calculation are compared with actual measured values. The proposed model provides a low-cost tool for the automatic control and simulation of the steam generating process. The “parity-space” algorithm is used to demonstrate the applicability of the mathematical model for sensor fault detection and identification purposes. This technique provides a powerful means of generating temporal analytic redundancy between sensor signals. It demonstrates good detection rates of sensor errors using relatively few steps of scanning time and allows the reconfiguration of faulty signals.     

10ns～500ns宽度连续可调的快速光脉冲发生器

脉宽可调的脉冲发生器常用于精密检测。本文阐述了一种运用叠加原理设计的脉冲宽度从10ns到500ns连续可调的快速光脉冲发生器。在驱动电路中应用了脉冲叠加原理。