HL-2Aװ��NBI����Դ���Ƽ���Դ��ʵ�����

为提高NBI系统的稳定运行参数和可靠性,研制了一台基于高频开关电源技术的全固态调制输出负高压测试电源,并将HL-2A装置NBI系统原4套抑制极电源的电子管调制器改为基于IGBT串联技术的全固态调制器.对比原抑制极电源系统,给出了基于高频开关技术和IGBT串联技术的抑制极电源结构.结合NBI系统调试实验,通过调节抑制极电源电压,瞬态电流输出能力,分析了抑制极电源输出性能对离子源束流引出特性,离子源引出电极击穿特性的影响,获得了引出稳定离子束流的最低抑制电压.     

HL-2A中性束加速极电源分布式控制的设计与应用

针对HL-2A装置的中性束加速极电源系统的远程管理和监控,设计了以太网环境下的分布式控制系统。该系统核心部分是PC-104嵌入式工控机、数字接口卡、模拟接口卡以及控制软件。以中性束加速极电源系统为出发点,提出了控制系统的设计要求。从硬件设计和软件设计两方面,论述了分布式控制策略在中性束加速极电源系统中的具体实现。实验证明,该控制系统兼顾了远程管理和实时控制,实现了电源系统的稳定运行。     

ITER PF电源现场层监控系统网络拓扑延时分析

为保障ITER极向场(PF)电源系统的高实时性控制需求,根据其设备体积大、分布分散等特点,选取了支持多种设备连接拓扑的实时工业以太网现场总线EtherCAT作为ITER PF电源现场层监控系统的数据通讯协议.为研究ITER极向场电源现场层监控系统的实时性,分析了数据帧在几种适合ITER PF整流器单元现场层信号采集与控...     

EAST极向场超导线圈电源控制网络的可靠性研究

为满足EAST极向场超导线圈电源控制的高可靠性要求,结合电源控制网络的特点,采用双网热备份冗余技术进行可靠性优化,并改进了相应软件。对比分析了优化前后控制网络的可靠性,结果表明软硬件优化提高了系统的可靠性,满足了电源控制的高要求。     

EAST极向场电源本地控制器软件设计与实现

本地控制器是EAST (Experimental Advanced Super—conducting Tokamak)极向场电源控制系统重要的子系统,实现对12套电源系统的实时控制,设备状态监控以及系统保护。本地控制器采用主从结构的实时控制软件架构,共享内存实现内部数据传输,脉冲式消息传递触发进程执行;通过现场总线、硬件板卡、反射内存网络等与现场设备和主控制器进行数据传输;通过数字移相板卡实现对整流器的环流、四象限等运行控制。经实验测试,该设计运行稳定,能满足极向场电源控制系统对本地控制器的实时性可靠性的需求。     

基于实时Linux的极向场电源主控制系统的设计

为了满足极向场电源控制系统严苛的实时响应的要求,选择实时Linux系统作为系统平台,采用一个开放源代码的、基于C/C++的Eclipse可扩展的开发平台作为开发工具,完成极向场电源主控制系统的设计,实现了在一个控制周期内(1ms)对极向场电源系统的12套本地控制器的实时通信和实时控制。对极向场电源主控制系统的高速通信和实时控制、稳定可靠等关键问题给出了可行的实践性的解决方法。经实验测试,该设计运行稳定,能满足极向场电源控制系统的实时需求。     

实验物理和工业控制系统在极向场电源控制系统中的应用

介绍了实验物理和工业控制系统（EPICS）的总体结构和特点,以及极向场电源控制系统监控网络的结构和特点,特别是EPICS设备支持在极向场电源控制系统的监控网络中的开发和应用。系统实现了实时监控极向场电源系统的现场设备和开关分合控制,实现了对极向场电源控制系统的电源控制单元的配置参数设置、控制模式的设置、时序控制等,并能及时报警、定位故障点。该系统监控的数字量及模拟量信号近2000路,且支持多用户操作,具备良好的跨平台移植性和扩展能力。经实验测试,该应用运行稳定,能满足极向场电源控制系统监控网络的需求。     

实验物理和工业控制系统在极向场电源控制系统中的应用

介绍了实验物理和工业控制系统（EPICS）的总体结构和特点,以及极向场电源控制系统监控网络的结构和特点,特别是EPICS设备支持在极向场电源控制系统的监控网络中的开发和应用。系统实现了实时监控极向场电源系统的现场设备和开关分合控制,实现了对极向场电源控制系统的电源控制单元的配置参数设置、控制模式的设置、时序控制等,并能及时报警、定位故障点。该系统监控的数字量及模拟量信号近2000路,且支持多用户操作,具备良好的跨平台移植性和扩展能力。经实验测试,该应用运行稳定,能满足极向场电源控制系统监控网络的需求。     

一种基于MAX8677A和PF6290的WSN节点电源系统的设计

介绍一种无线传感器网络(WSN)中节点系统电源的设计方案。该电源系统需要为节点系统中的微处理器、无线通讯、数据采集和传感器等单元提供工作电源。该电源系统既外接220V交流,内部也有3.7V锂电池;系统工作时自动对供电方式进行对选择,并完成锂电池充电任务。电源系统具备动态电源管理功能,通过微处理器实现节点系统的低功耗休眠状态及其唤醒机制。详细地描述了该电源系统的硬件结构,给出了芯片描述和具体的电路设计图,并介绍了节点系统休眠和唤醒的软件流程。     

HT-7U装置极向场电源变流系统的研制

介绍了HT-7U极向场电源中所使用的变流系统,提出了一种新的四象限运行控制方法,解决了极向场电源设计和制造的难点。实现了15kA的有环流运行。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.