船舶双推进轴系振动分析软件开发研究

为了预防船舶行进过程中轴系振动过大带来的危害,设计实现了船舶双轴系振动分析软件系统,实现了船舶运行过程中轴系振动的分析显示;对扭振和回旋双通道实时测试采集的数据进行了处理,剔除误差过大的野值,提高振动分析的精确度,并对扭振振幅数据进行定点DFT变换,找出扭振在高谐次上的异常振幅尖峰,以预防船舶在此转速下因扭振振幅过大带来的危害;实船测试表明,该系统测试精确度高,振动分析结果显示直观,满足了船舶双推进轴系振动分析的设计要求。     

船舶轴系振动教学演示实验台架设计与实验分析

通过船舶轴系振动理论和实践特点的分析,设计和制作了船舶轴系振动教学演示实验台架.同时,在教学演示实验台架与实船之间开展了比对实验,在船舶轴系振动信号、轴系扭振频谱、横振频谱、纵振频谱等关键实验环节进行了比对分析和讨论,得出了船舶轴系振动教学演示实验台架的可用性和可比性.     

用单光纤光栅实现扭转与温度的双参量传感测量

采用一种新颖的扭梁设计结构 ,利用单光纤光栅成功地实现了扭转 (扭转角或扭矩 )与温度的双参量同时测量。该方法能够有效地解决扭转角与温度的交叉敏感问题 ,且光纤光栅波长的变化对扭转角、扭矩及扭应力 (力臂一定时 )均呈线性关系。在 - 40°～ +32°范围内 ,扭转角、扭矩和温度的传感灵敏度分别达到 0 .19nm (°)、3.2 9nm Nm和 0 .0 3nm ℃ ,波长线性调谐范围可达 14.2 0nm。     

回转件弯扭测量系统及其不确定度分析

为了准确诊测轴系振动特性,基于激光多普勒的频移原理,提出一种能同时测量旋转轴系弯曲振动、扭转振动和轴系旋转速度的方法。设计了能分离弯扭振动的多普勒外差干涉光路,结合光学差拍及参考光技术,构建了测量系统数学模型。对影响激光多普勒弯扭振动测量的主要因素进行了分析,讨论了各参量对测量结果的影响,并给出了相应的测量不确定度。在置信水平为95%时,瞬时转速的不确定为0.079 r/min,弯曲振动速度分量的不确定为0.001 4 mm/s,其精度能满足旋转状态下轴系振动的综合测量要求。     

CAS压气机转子中跨声速三元流动的S_1/S_2流面准三元迭代解

本文对我所跨声速单级轴流压气机0.8和0.9设计转速下转子通道内及其上、下游的流场,进行了S_1、S_2两类流面迭代计算,分析了三元跨声速流场,并与使用双焦点激光测速仪的测量结果进行了比较。在分析计算中,以激光测量的出口绝对气流角分布,常规测量的出口滞止压力分布及通过扭矩测量值校正得到的转子效率为输入参数,进行了6轮迭代计算,得到了跨声流场的收敛解。计算结果与测量值较接近。     

相对转动运动学方程的级数解

为解决相对转动体非线性运动微分方程的计算难题，构造了一种级数解耦方法，把微分方程转化为代数方程求解，得到了相对转动体运动方程的级数解.据此可以计算工程应用中稳态相对转动体的真实转速波动.同时该法可实现测控标定仪器的转动体匀速旋转时的不均匀性测量误差分离，也为大型复杂重型旋转轴系在线实时扭振监测提供了高效算法. 关键词： 相对转动 运动学方程 速度波动 级数解     

压气机转子内高亚声速三元流场计算及与激光测量值的比较

作为跨声速轴流压气机研究计划中的一个部份,使用双焦点激光测速仪测量了转子上下游及转子通道内的流场,同时进行三元流分析计算并与测量结果进行比较.本文着重介绍所采用的三元分析计算方法.它以激光测量的出口绝对气流角分布,常规测量的出口总压分布及扭矩测量得到的转子效率作为计算的输入参数,从而得到转子内部的详细流动.在部分转速下的计算结果与测量结果是相当接近的.     

柴油机轴系扭振系统的强非线性主共振

研究柴油机轴系扭振系统强非线性问题.根据拉格朗日方程建立柴油机轴系扭振系统的动力学模型,通过参数变换,应用Modified Lindstedt-Poincaré方法得到柴油机轴系扭振系统强非线性主共振的幅频响应方程,分析系统不同参数对主共振幅频响应的影响.结果表明,系统的幅频响应曲线存在跳跃,随着简谐力矩的减小和阻尼的增大,系统的非线性跳跃减弱,系统的振幅减小,系统主共振的区域也随之减小;随着调谐参数的变化,系统的主共振力幅响应曲线存在两种拓扑结构.MLP方法得出的近似解析解与龙格库塔法得出的数值解吻合.     

基于激光多普勒技术扭振测量的研究

提出一种基于激光多普勒技术和光学外差原理对高速回转机械进行扭振测量的新方法,分析了工作原理,推导出光路部分的数学模型,并通过实验分别验证了测量方法的可行性和准确性。高相干激光投射到转轴同一个截面上2点,反射光的多普勒频移正比于转轴转速,通过光学配置,使前后两个时刻的多普勒频移光信号在光探测器上发生光学混频,光电流拍差正比于转轴在两个时刻的速度差,控制两个时刻时间差很小,直接得到角加速度。与其他激光多普勒扭振测量方法相比,该方法直接测量转动角加速度,在保证测量精度的前提下,提高了扭转振动测量的实时性,极大地扩展了扭振测量的动态范围,对大型回转机械运行状态监测和故障诊断具有重要意义。     

多晶氧化物薄膜及复合膜系应力模型

基于膜层结构的弛豫现象,建立了一个多晶膜的应力演化模型,并通过线性组合给出了复合膜的生长应力模型。利用双光束基底曲率测量装置实时测量了电子束蒸发氧化铪、氧化硅多晶膜及其复合膜的应力演化过程,并对测量结果进行了拟合分析。     

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.     

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.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.