Model GC1312S Multifunction Integrated Optical Circuit Devices

Model GC1312S multifunction integrated optical circuit device (MIOC) used in inertial-grade interferometric fiber optics gyroscopes(IFOGs) is fabricated by annealing and proton exchange process(APE) 。The unique feature of the device is the incorporation of the beat detection circuit besides all the features the conventional single Y-branch multifunction integrated optical circuit devices have.The device structure ,operation principle and typical characteristics, etc, are briefly presented in this paper.     

相干光纤通信系统

相干光通信简介,外差探测基本原理相干探测基本方式。     

A finite element model for the analysis of flexible tube Coriolis mass flow meter using first order shear deformation shell theory

The numerical modelling of Coriolis Mass flow Meter (CFM) is essential for predicting its outcomes accurately in terms of sensitivity as well as exact mass flow rates. In the majority of mathematical and numerical modelling concerning the flexible structures, the authors neglect the dimensional and shape variation of the structure due to self-weight. The shell based on the First-order shear deformation shell theory (FSDST) is preferred in modelling shells compared to the beam model. The current work includes numerical modelling of CFM using eight noded isoparametric shell elements and twenty noded Acoustic fluid elements. The fluid energy describes as the potential, and the dynamic boundary condition is assumed utilising the displacement of structure and potential of the fluid. The fluid dynamic equation combining suitable numerical model, fluid-structure interaction module and cross-correlation technique helps to achieve the numerical modelling of CFM. The numerical model of CFM utilises the Newmark Beta method of numerical integration, and the response of two equidistant locations from the point of tube excitation is acquired. For the flexible tube conveying fluid, there exists sagging of tube due to the weight of tube and fluid. The Coriolis force and the external excitation force cause the fluid conveying tube to bend and twist, and as a result, the velocity responses picked from two equidistant points shows a difference in phase. The effect of sagging leads to a lower phase shift and time decay, and hence the sensitivity of the CFM is low for low pre-stretched flexible tubes. The pre-stretching of flexible tubes reduces the effect of sagging, facilitates to regain the cylindrical shape of the tube and increases the sensitivity of CFM. The result reveals that the shell element along with the three-dimensional acoustic fluid element provides the most accurate numerical model for the CFM and the change in sensitivity, as well as the change in mass flow measurements, can appropriately be analysed with the help of this numerical model. The amplitude of the velocity of the structure, measured from the two equidistant points, shows a difference. The severe variation in amplitude of velocity measured from two points is an implication of the out of plane deflection of the tube. For a CFM made up of metal tubes, the amplitude of velocity variation is minimal and ignored by the authors.     

Development of High—precision Rotary Encoder Using Semicounductor Laser

In this paper,the operation principle of laser rotary encoders is expounded and the optical quadruple frequency technology used in laser rotary encoders in ex-plained,and the design idea of optical system in Φ 66 mm laser rotary encoder is mainly introduced,as well as the choice of principal devices.     

高双折射保偏光纤拍长测试及Mueller矩阵分析

为了测量高双折射保偏光纤的拍长,采用偏光干涉效应的方法,构建由宽谱光源、带保偏尾纤的起偏器和光谱分析仪组成的全光纤光路测试系统。从理论上用Mueller传输矩阵方法推导了到达光谱仪的光强公式,利用该方法构建实验系统对熊猫型保偏光纤的拍长进行了测试,获得了该保偏光纤拍长的测量数据。结果表明,由待测保偏光纤的偏光干涉效应引起的光强波动以一定的周期间隔表现在光谱变化上,波动的相对幅度与待测保偏光纤主轴与起偏器的保偏尾纤主轴夹角有关,当夹角均为±45°时波动的相对幅度最大。只要在实验中测量出光谱波动的周期,就能够根据理论计算出给定波长处的保偏光纤的拍长。     

激光双谱线功率的不一致性与拍波干涉仪对准精度的关系

双谱线功率一致性是拍波干涉测长方案对激光光源提出的特殊要求。本文从拍波干涉仪对准方法的实际出发,在分析双谱线拍波干涉仪输出信号的基础上,研究了双谱线功率不一致与拍波干涉仪对准精度的关系,提出了基本对准盲区和盲区扩大量的新概念,建立了描述盲区扩大量与双谱线相对功率差之间关系的解析表达式。为设计拍波干涉仪的激光稳定环路和提高拍波干涉仪的对准精度提供了理论分析工具。     

正弦波模型化测量方法及应用

本文对应用较多的几种正弦波模型化测量方法进行了综述,它们是曲线拟合法、直方图统计分析法、FFT法和拍频法。较详细地介绍了这几种测量方法的典型用途以及特点,通过比较几种方法的优缺点,讨论了它们应用中的局限性。     

浅谈井下语音设备利用单片机发声的原因

井下语音设备发声主要利用AT89C51单片机制作的发音电路,介绍了AT89C51单片机产生音乐的要素,由AT89C51单片机制作的发音电路和通过汇编好的语言程序而实现的蜂鸣器,以及单片机演奏音乐的原理.     

Resonance and the Perception of Musical Meter

Many connectionist approaches to musical expectancy and music composition let the question of ‘What next?’ overshadow the equally important question of ‘When next?’. One cannot escape the latter question, one of temporal structure, when considering the perception of musical meter. We view the perception of metrical structure as a dynamic process where the temporal organization of external musical events synchronizes, or entrains, a listener's internal processing mechanisms. This article introduces a novel connectionist unit, based upon a mathematical model of entrainment, capable of phase- and frequency-locking to periodic components of incoming rhythmic patterns. Networks of these units can self-organize temporally structured responses to rhythmic patterns. The resulting network behavior embodies the perception of metrical structure. The article concludes with a discussion of the implications of our approach for theories of metrical structure and musical expectancy.     

Tip-to-sample distance dependence of an electrostatic force in KFM measurements

In most scanning probe methods like an atomic force microscopy, a cantilever is mechanically vibrated in order to obtain topographies. Therefore, a tip-to-sample distance periodically changes during the scanning. Since the electrostatic force, which is a long-range force, is used for potential feedback in Kelvin probe force microscopy (KFM), such mechanical vibration leads to the fluctuation of the electrostatic force between the tip and the sample. In this study, firstly, we performed two-dimensional simulations of the electric fields between surfaces of the tip and the sample and evaluated the tip-to-sample distance dependence of the electrostatic force. Secondly, we experimentally confirmed the existence of the fluctuation of the electrostatic force and the tip-to-sample distance dependence of the electrostatic force was evaluated. Both the simulations and the experiments on the tip-to-sample distance dependence showed the importance of considering the tip sidewall effect in the KFM potential determination.