虚拟仪器在射频超导量子干涉仪控制电路中的应用

本文简要介绍LabVIEW开发的射频超导量子干涉器(rf SQUID)自动控制系统的虚拟仪器,系统可对超导量子干涉器的工作点进行调整和显示,实现了LabVIEW软件系统与第三方硬件的结合.本文将对系统工作原理、硬件电路组成和软件的设计做简要介绍.     

基于USB传输的rf SQUID自动测量系统

本文报告了基于USB传输的计算机控制的射频超导量子干涉器(rf SQUID)自动控制测量系统的实现,系统可对rf SQUID的工作点进行调整和显示.本文将对系统工作原理、硬件电路和软件的设计做简要介绍.     

超导量子干涉仪计算机自动控制系统

提出了计算机控制的射频超导量子干涉器自动测量、控制系统的实现 ;并对系统工作原理、硬件电路和软件编制的设计思想做了简要介绍。     

高Tc超导量子干涉器及其应用

本文简述了超导量子干涉器的基本用途，高Ｔｃ超导量子干涉器的研究现状，探讨了高Ｔｃ超导量子干涉器在我国可能最早实现实用化的优先领域，对我国高Ｔｃ超导量子干涉器研究和应用工作的计划安排提出了一些设想．     

基于嵌入式系统的射频超导量子干涉仪控制系统

本文介绍了嵌入式系统在射频超导量子干涉仪控制系统中的应用，提出了嵌入式系统的整体方案，并对系统工作原理以及设计思想做了简要介绍．     

超导量子干涉器(SQUID)原理及应用

严谨的超导量子干涉器原理的阐述是非常深奥和繁杂的,我们在这里采用简明的物理图像和数学语言论述超导量子干涉器的原理及应用,以推动“大学物理现代化”的进程.     

我国高温超导材料研究进展

本文概述了我国在高温超导材料研究方面的最新进展，较系统地介绍了超导块材和薄膜的制备方法及性能，并简单地介绍了高温超导材料在超导量子干涉器件、超导天线、磁屏蔽和磁通变换器等方面的应用．     

超导量子干涉器件

超导现象是一种宏观量子现象.磁通量子化和约瑟夫森效应是两个最能体现这种宏观量子特性的物理现象.超导量子干涉器件(superconducting quantum interference device,SQUID)是利用这两个特性而形成的超导器件.SQUID器件在磁信号灵敏探测方面具有广泛的应用.本文简要介绍低温超导和高温超导SQUID器件的相关背景和发展现状以及应用领域.     

射频超导量子干涉器的外磁通调制测量磁通量子

在外磁通作用下射频超导量子干涉器（ＲＦＳＱＵＩＤ）超导结两边量子相位差受到调制，干涉器吸收谐振回路能量的同时也影响谐振回路，回路输出电压与外磁通为三角波曲线关系，再受静磁场作用时曲线移动，据此可磁通量子。     

超导量子干涉仪发展和应用现状

作为灵敏度极高的磁传感器，超导量子干涉仪（即SQUID）在生物磁测量，大地测量，无损探伤等方面获得了广泛的应用．本文主要介绍了超导量子干涉仪的基本原理，制作工艺以及发展现状，并总结了目前的应用热点和国内外研究进展，对我国如何开展该方面的研究进行了探索和分析．     

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.     

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.     

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.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Research on beamforming method for dual-line array with space mismatch between the two line arrays

The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.     

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.