исп-22中型石英攝谱仪的自动装置

文中简要介绍利用三个电动式时间继电器,以控制弧烧时间,预燃时间及照相板盒的移动距离,从而简化了工作的步骤,缩短了工作的时间和提高了工作的效率。     

加强思想政治工作为多出成果快出人才作出新贡献

西安光机所自一九六二年三月建立以来,已经走过二十年的战斗历程。二十年来,按上级党委要求,所党委始终把搞好科研工作作为党的工作中心,并遵循思想政治工作是一切经济工作生命线的原则,不断加强思想政治工作。在工作中坚了理论联系实际、科研为国防建设和国民经济服务的方向,坚持勤俭建国、自力更生、发奋图强的革命精神,团结广大科技人员,调动了全体人员的积极性,从而推动了科研的发展,在为国防建设和国民经济服务中作出了应有的贡献。     

三电极气体开关自陡化技术及应用

 根据Trigatron的触发要求设计了脉冲变压器型驱动源、三电极气体开关。在多种驱动模式下对三电极开关的自陡化参数进行统计分析,选择最优的自陡化工作模式。通过研究自陡化工作模式,优化了三电极开关工作极性、工作电场、紫外辐照强度和辐照时间。试验结果表明：增加陡化环节后,Trigatron的击穿概率有了明显提高,击穿时刻延迟和抖动明显降低,扩大了Trigatron稳定工作的欠压比范围。     

分布式制冷系统中的负荷分配性能优化研究

针对分布式制冷系统中多台制冷装置并行工作的特点,深入研究了在分布式制冷系统中制冷需求模型。采用基于PLC控制器的制冷系统控制方案,通过设计制冷控制系统对分布式制冷系统的各个工作单元进行控制和调节,动态调整各个工作单元的负荷分配,从总体上对分布式制冷系统的性能进行优化。重点对制冷控制系统的设计方案进行了阐述,详细描述了控制系统的工作过程,并给出了负荷动态分配策略及性能优化方案。     

声学消息

中国声学学会学术交流工作经验交流会会议纪要中国声学学会学术交流工作经验交流会于１９９９年４月１５日至１８日在昆明市召开,参加会议的代表２０人。中国声学学会理事长张仁和院士出席了会议,秘书长宗健高级工程师主持会议．张仁和理事长向各位代表传达了民政部有关社会团体清理整顿工作会议精神和中国科协五届四次全委会会议精神,宗健秘书长对学会近几年来的学术交流工作做了全面地总结．各分会、地方学会的代表都认真地总结了本学会多年的学术交流工作。本次会议结合代表们各自多年工作体会,就如何进一步发挥学术交流主渠道的作用…     

关于半导体光激射器工作电流范围的分析

本文直接利用阈值电流随温度变化的实验关系,通过解热传导方程,得到了连续及脉冲工作状态下起始工作电流、最大工作电流及临界阈值电流的定量结果,供研制参考。其中全面地考虑了结内及体内发热的贡献,后者可用一归一化等效体内发热电阻r来表征。连续工作状态的分析表明,体内发热的影响不可忽略。对脉冲工作状态的分析,分别考虑了脉冲宽度和重复频率的影响。指出:在兼顾功率和重复频率的情况下,脉冲工作比以取0.03左右为宜。当实际应用中对重复频率要求不高时,为了提高功率,取重复周期比二极管热弛豫时间约大3倍比较合适。如果要求重复频率很高,则器件性能主要由脉冲工作比决定。文中利用所得结果结合实例进行了讨论,并讨论了脉冲工作情况由于结温变化所导致的发射频谱展宽效应。     

有效抑制光子晶体加载矩形谐振腔中模式竞争的方法

研究了光子晶体加载矩形谐振腔,针对传统光子晶体加载无法完全抑制模式竞争的问题,提出了特性阻抗和介质加载方法进行改进,完全实现了谐振腔的高次模式的单模工作,为抑制高次模式工作的谐振腔中模式竞争的问题提供了一种新方法.在此基础之上,采用解析方法以及高频仿真软件HFSS,设计了一个采用TM₅₃₀高次模式工作的传统光子晶体加载的谐振腔,进一步采用了该新方法对其进行改进,并深入分析了采用这种方法抑制模式竞争的物理原因.计算结果表明,新方法能有效抑制模式竞争,实现谐振腔的高次工作模式的单模工作. 关键词： 光子晶体 谐振腔 模式竞争 特性阻抗     

CCD工作信号的噪声分析与处理

对CCD自身噪声以及工作过程中的各种噪声干扰进行了分析,并对相关双采样法和相关四采样法两种主要噪声处理方法的基本原理进行了详细介绍,对各自工作时序、性能特点和适合的工作领域进行了仔细研究和探讨。     

交叉增益调制型波长转换器噪声特性的研究

对基于半导体光放大器的交叉增益调制型波长转换器相向和同向两种工作方式进行了研究。实验上分别实现了两种工作方式在1550nm波段的波长转换,比较了相同外部条件下两种工作方式的噪声特性,在全面考虑放大自发辐射噪声及其消耗载流子,增益谱的色散性和有源区内部损耗等因素的基础上,运用放大器的分段模型,计算了不同条件下两种方式的输出噪声功率,结果表明：相向型工作方式受放大自发辐射噪声的影响要远大于同向工作方式,输出放大自发辐射噪声功率的大小主要取决于载流子浓度的高低,而载流子空间分布的不均匀程度则决定两种工作方式输出噪声功率的差值大小。     

二极管泵浦Nd:YAG圆片激光技术研究

介绍了热容激光技术的发展历史及现状,介绍了固体激光器热容方式工作的基本原理,报道了二极管泵浦NdYAG圆片激光器热容方式工作的实验结果.用热像仪测量了激光器工作时增益介质通光面上的温度分布特性;采用干涉测量的方法测量了工作中的增益介质的与光束传输方向相垂直的方向上的折射率分布特性;结果表明片状固体增益介质热容方式工作对振荡光束波前畸变影响很小.给出了与光束传输方向相垂直的截面上增益介质的荧光分布.得到输出平均功率达47.5 W,此时的光-光转换效率为17%.     

Some focusing properties of chirped gratings

In the past the focusing properties of chirped grating structures have been investigated in various disciplines including optics, acousto-optics and acoustics. In this paper we present the results of a detailed theoretical and experimental study of one such amplitude grating structure, namely the chirped optical diffraction grating, although many of the conclusions are of more general validity. We derive some useful fundamental properties of such focusing gratings, and show that to first order their behaviour is similar to that of various other classical components such as focusing lenses, grating spectrometers and matched filters for chirped waveforms. However, we also describe a range of second-order differences in behaviour, for example concerning the physical location of the multiple foci, and the sidelobe structures within and perpendicular to the focal plane. For devices of large numerical aperture we demonstrate the advantages of using a non-linear grating structure — for example, for sidelobe suppression in the focal plane - and point out that surface acoustic wave (SAW) techniques can be used to generate the non-linear chirp waveforms necessary to implement such gratings in acousto-optic devices.     

全国声学标准化技术委员会的发展与国家声学基础测量方法标准体系建设

首先回顾了全国声学标准化技术委员会自1980年成立以来,在国家声学标准制、修订方面所取得的一批重要的标准研究成果。经过全国声学领域历届委员和专家30年来的共同努力,截止2009年共制、修订声学方面国家标准166项次,形成了目前归口声标委管理的131项现行有效的国家标准,由此也建立了涵盖声学基础、噪声、建筑声学、超水声四大类标准的国家声学基础测量方法标准体系。这些声学基础测量方法标准体系与国家声环境质量、噪声排放等环保标准和工程建设标准、电声和音视频等标准共同构成了较为完整的国家声学标准体系。最后结合声标委今后要开展的标准工作,提出了进一步完善国家声学基础测量方法标准体系的细部构想,可以相信,将来随着这些标准的陆续出台,我国声学标准体系会更趋完善。      

量子声学及其应用

量子声学是声学的一个前沿和刚刚活跃起来的分支,是继电子学、光子学之后发展迅速的一门新学科,本文就量子声学的诞生,定义和所涉及的内容进行了讨论,较为系统地介绍了与量子声学有关的理论、材料、器件和应用进展。     

通信声学的发展及研究现状

人类作为信息交流的主要信息产生源和信息接收槽,语言声学、心理声学和生理声学在信息技术中发挥着越来越重要的作用。作为声学与信息技术相互渗透的产物-通信声学,近十几年来随着数字信号处理技术的发展,其研究和应用领域得到了很大的扩展。本文在简述通信声学产生和发展的必然性和必要性之后,主要介绍了通信声学目前的研究领域及其应用。     

Features of underwater acoustics from Aristotle to our time

Underwater acoustics has been one of the fastest growing fields of research in acoustics. In particular, the 20th Century has taken our understanding of underwater acoustics phenomena a great step forward. The two World Wars contributed to the recognition of the importance of research in underwater acoustics, and the momentum in research and development gained during World War II did not reduce in the years after the war. The so-called cold war and the development in computer technology both contributed substantially to the development in underwater acoustics over the second half of the 20th Century. However, the very widespread field of underwater acoustic activities started nearly 2300 years ago with human curiosity about the fundamental nature of sound in the sea. From primitive philosophical and experimental studies of the velocity of sound in the sea and through centuries of successes and failures, the knowledge about underwater acoustics has developed into its high-technological status of today. In particular the development through the period from Aristotle (384–322 BC) to 1960 formed the basis for the tremendous research and development efforts we have witnessed in our time. In this paper most emphasis will be put on the development in underwater acoustics through this period of nearly 2300 years duration, and only the main trends in later research will be mentioned.     

Plasma-maser instability of the ion acoustics wave in the presence of lower hybrid wave turbulence in inhomogeneous plasma

A theoretical study is made on the generation mechanism of ion acoustics wave in the presence of lower hybrid wave turbulence field in inhomogeneous plasma on the basis of plasma-maser interaction. The lower hybrid wave turbulence field is taken as the low-frequency turbulence field. The growth rate of test high frequency ion acoustics wave is obtained with the involvement of spatial density gradient parameter. A comparative study of the role of density gradient for the generation of ion acoustics wave on the basis of plasma-maser effect is presented. It is found that the density gradient influences the growth rate of ion acoustics wave.     

厅堂声学一百周年(1895—1994)

本文介绍自Ｗ．Ｃ．Ｓａｂｉｎｅ以来１００年厅堂声学的发展简史，包括室内声学理论，音指标与评价，声学测试方法，缩尺模型技术，计算机仿真技术及厅堂设计的发展，现状及关于今后研究方向的前瞻。     

A craft-project loudspeaker to serve as an educational demonstration

Moving-coil loudspeakers typify the interdisciplinary nature of acoustics: in order to reproduce sound, these devices employ principles of electricity, magnetism, mechanics, and acoustics. The widespread use of loudspeakers has made them a familiar and valuable opportunity to introduce students to acoustics. A low-cost loudspeaker project/demonstration is presented here that is built from scratch using common household items and craft supplies. A variety of educational topics may be illustrated with this device, making it appropriate for a wide range of academic levels.     

An explicit time-domain finite element method for room acoustics simulations: Comparison of the performance with implicit methods

This paper presents the applicability of an explicit time-domain finite element method (TD-FEM) using a dispersion reduction technique called modified integration rules (MIR) on room acoustics simulations with a frequency-independent finite impedance boundary. First, a dispersion error analysis and a stability analysis are performed to derive the dispersion relation and the stability condition of the present explicit TD-FEM for three-dimensional room acoustics simulations with an infinite impedance boundary. Secondly, the accuracy and efficiency of the explicit TD-FEM are presented by comparing with implicit TD-FEM using MIR through room acoustics simulations in a rectangular room with infinite impedance boundaries. Thirdly, the stability condition of the explicit TD-FEM is investigated numerically in the case with finite impedance boundaries. Finally, the performance of the explicit TD-FEM in room acoustics simulations with finite impedance boundaries is demonstrated in a comparison with the implicit TD-FEM. Although the stability of the present explicit TD-FEM is dependent on the impedance values given at boundaries, the explicit TD-FEM is computationally more efficient than the implicit method from the perspective of computational time for acoustics simulations of a room with larger impedance values at boundaries.     

从建筑声学到环境声学

本文简述环境声学的发展过程以及在厅堂音质、环境噪声和噪声控制方面的新世纪展望。