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A new method to evaluate imaging quality of CCD cameras

Optoelectronics Letters 2005年第2期 72-74页

作者： LI Wen-juan-(1,2., DU Hai-hui-3. DAI Jing-min-1,and CHEN Ying-hang-3.1.School of Electrical Engineering & Automation,{2.,harbin {2.,China 2.Electrical & Electronic Engineering College,harbin University of Science and technology,harbin 150040,China 3.3.3.institute of No.3.Research Academe of China Aerospace Science & Industry Corporation,Beijing 100074, China

In order to evaluate the imaging quality of CCD cameras fully and rapidly,the minimum resolvable contrast (MRC) is presented in this paper and the system of measuring MRC is constructed as well,in which two integrating spheres are proposed to illuminate two sides of the target *** variable contrast can be obtained by regulating the luminance of integrating spheres. experimental results indicate that the error of measuring luminance is within ±0.3.cd/m-2.MRC rises with the increase of the spatial *** experimental results show that the method proposed is an effective approach to evaluate the imaging quality of CCD cameras.

关键词： CCD

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Strengthening and toughening of TiC ceramics by short carbon fibers

Strengthening and toughening of TiC ceramics by short carbon...

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International Symposium of Young Scholars on mechanics and Material Engineering for Science and Experiments

作者： Gui-Ming Song Yu Zhou School of Materials Science and Engineering harbin institute of technology harbin {2. China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

ISBN: (纸本)1880132796

＜正＞ In order to improve the strength and toughness of TiC materials, especially the elevated temperature strength, TiC composites containing 2.vol% short carbon fiber （C/TiC） were produced by vacuum sintering at 2.00℃, 3.MPa for 1h. The strength of the composite is 593.Pa at room temperature and 43.MPa at 1400℃, and the fracture toughness is 6.87MPa-m1/2. A modified role-of-mixture formulation is used to estimate the strengthening effect of the fibers. The toughening effect of the fibers is calculated by adding up the individual contributions of crack bridging, fiber pullout and crack deflection. The calculated results of the strength and fracture toughness of the composite agree well with the experimental results.

关键词： TiC composites carbon strength fracture toughness hot pressing technique

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SPEED-STABILIZATION CONTROL OF A HIGH-SPEED PM SYNCHRONOUS MOTOR WITHOUT HIGH-PRECISION SENSORS

SPEED-STABILIZATION CONTROL OF A HIGH-SPEED PM SYNCHRONOUS M...

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2.02.IEEE十区计算机、通信、控制和电机工程会议

作者： ZOU Jibin Senior Member, IEEE XU Yongxiang SHANG Jing LIANG Weiyan department of Electrical Engineering, harbin institute of technology, {2., China, {3.

Speed-stabilization control of a 3.,000 rpm high-speed PMSM (permanent magnat synchronous motor) isachjeved without speed sensors. The rotor position of the PMSMis detected by a discrete Hall sensor with the resolution of ±90electrical degrees. Circuits based on Phase Locked Loop (PLL)are designed to obtain the speed signal and high-precision rotorposition signal. Two filters with different constant time are de-signed to improve the dynamic performance of the-speed-stabilization system because the low-pass filter is adapted in thespeed loop. experimental and simulated results show the validityof the proposed method.

关键词： high-speed permanent magnet synchronous motor speed-stabilization control

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Research on Fracture Behavior of Film-substrate System

Research on Fracture Behavior of Film-substrate System

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第一届工程科学与力学中的计算方法国际会议

作者： Baoliang Liu and Xianshun Bi department of Mathematics and mechanics Heilongjiang {2. of Science and {3. harbin 15002. China

＜正＞The last decade has seen enormous progress in the area of integrated circuits, microelectronic, and micro-machined devices. These engineering systems typically consist of dissimilar materials joined together on a substrate, i.e. the film-substrate composite system. Owing to the high performance demands of engineering devices, film technology profoundly affects the lifetime of materials. In filming process, the thermal stress exists due to the difference among the thermal expansion coefficients of the film and the substrate, which may result in cracking of the films. Thus, the reliability of these systems often depends on the fracture behavior of the films comprising the device and a good understanding of the possible failure mechanisms makes it possible to design more reliable devices. This study gives the problem of a crack in the film oriented perpendicular to the film-substrate interface with the crack tip fully within the film. Based on Beuth’s theory, three-dimensional model is simplified to plane strain problems, which obtains fracture mechanisms of a cracked film-substrate system by applying the boundary element method（BEM）. The method aptly resolves the problem involving stress concentration The results indicate: the stress intensity factor is affected by the different elastic mismatches and the thickness ratio of the film and the substrate, and it has remarkable increased with the decrease of the thickness ratio of the film and the substrate. The effect of the fracture behavior of film is negligible when the thickness ratio of the film and the substrate is more than 10. The conclusion has theoretical significance for researching fracture behavior of film-substrate system by experimental mental method. What’s more, this paper studies the special condition of the film-substrate system, which is the analysis of the fracture of the absence of any elastic mismatch between the film and the substrate, i.e. α=β=0, and revision of the formula of Xia and Hutchinso

关键词： film-substrate system crack stress intensity factor boundary element method

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Parameter Identification of Hydraulic Low Pressure Pipeline Transient Model Using Parallel Genetic Algorithms

Parameter Identification of Hydraulic Low Pressure Pipeline ...

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第五届流体传动与控制国际会议

作者： Yang Chifu~* Li Songjing Jiang Dan department of Fluid Control and Automation harbin institute of technology {2. Heilongjiang {3. China

＜正＞Parameter identification of pressure transient models accompanying cavitation and gas bubbles inside low hydraulic pipelines using parallel genetic algorithms（PGA）in a cluster of computers is presented. In this paper,pressure transient models are given to describe the flow behavior in a pipeline,and the numerical models of cavitation and gas bubbles are built to calculate the cavitation volume and gas bubble volume during the *** unknown parameters of the pressure transient mathematical models include the initial gas bubble volume,gas resolving time and gas releasing time *** identification of pressure transient mathematical models with genetic algorithms（GA）on a single computer usually takes seven or eight days,which is out of *** execution time of GA becomes high due to time consuming of evaluating fitness *** order to predict the pressure transients and shorten the execution time of GA,MATLAB Distributed Computing toolbox and MATLAB Genetic Algorithms toolbox are used to perform evaluation of fitness function at each generation by PGA,which is a parallel calculation on a cluster of *** on the minimization of the least-square errors between experimental data and simulation results,PGA is applied to search for global optimal model *** rate of computation time using PGA to using GA is acquired. Simulation results with identified parameters obtained by PGA are *** of simulation results with experimental data indicates that PGA is feasible to estimate unknown parameters in hydraulic low pressure pipeline transient model.

关键词： parallel genetic algorithms parameter identification pressure transients

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Numerical Simulation and Experiment of Cavity Growth During Superplastic Bulging of Magnesium Alloy ZK60

Numerical Simulation and Experiment of Cavity Growth During ...

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The Fourth International Conference on Physical and Numerical Simulation of Materials Processing (ICPNS’2.04)

作者： Yandong YU, Kaifeng ZHANG, Hairong ZHENG and Daming JIANG department of Materials Engineering, harbin institute of technology, {2., {3., P.R.China

In this paper, numerical simulation and experimental studies on cavity growth were carried out during the bulging process of superplastic magnesium Alloy. A three-dimensional rigid-viscoplastic finite element program has been developed and applied to predict the cavity radiusand volume fraction of cavity growth. The final prediction on the cavity radius and volume fraction distribution was exhibited as colorful shade pictures. The experimental studies wereperformed under similar conditions to the numerical one and provided for quantitativecomparison. According to the metallography observation, the radius and volume fraction of cavity growth was quantitative achieved by using Profound-Iron&steel software. The numerical results were in reasonable quantitative agreement with the experiment.

关键词： Magnesium alloy Cavity Numerical simulation Superplastic bulging

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Mechanical Properties of Metal Honeycomb SandWich Panel

Mechanical Properties of Metal Honeycomb SandWich Panel

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International Conference on experimental mechanics 2.08 (ICEM 2.08)

作者： Guangping Zou~(1 *) Jie Lu~1 Jun Liang~2.Zhongliang Chang~1 1 Center for mechanics Testing harbin Engineering University harbin China 2.Center for Composite Materials {3. harbin China

＜正＞Many developed countries are committed to work with the aerospace industry to develop a Reusable Launch Vehicle（RLV） because it will greatly reduce the cost of repetition launching into *** space shuttle"Colum... 详细信息

关键词： MTPS mechanical properties digital speckle correlation method ESPI debonding detection

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激光自混合干涉仪的实验研究

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中国激光 2001年第1期28卷 29-32页

作者：马军山王向朝方祖捷强锡富中国科学院上海光机所上海201800 哈尔滨工业大学哈尔滨150001

分析了激光自混合干涉仪位移测量误差及特点 ,提出了干涉仪的设计原则。对激光自混合干涉仪的系统稳定性与测量分辨力进行了实验研究 ,给出了改善系统稳定性与测量分辨力的有效方法。

关键词：自混合干涉仪半导体激光器位移测量误差

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双振子模型手性分子介质的二次谐波理论

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物理学报 2003年第2期52卷 372-376页

作者：郑仰东李俊庆李淳飞哈尔滨工业大学物理系哈尔滨150001

推导了在二次谐波条件下耦合双振子模型手性分子的一阶超极化率 ,给出了薄膜手性介质的二阶极化率 ,分析了分子的微观参量对二次谐波产生效率的影响 .理论计算所得的偏振旋转角谱和已有的实验结果相符 .

关键词：双振子模型手性分子分子极化率介质极化率二次谐波非线性光学

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Nonlinear optical response and optical limiting in a new hexagonal prism shaped metal cluster W2.g4S8(dppy)4

Nonlinear optical response and optical limiting in a new hex...

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第九届全国光电技术学术交流会

作者： CHANG Cun 1,CHANG Qing1,SONG Ying-lin2.(1 College of Electronic Engineering,Heilongjiang University,harbin 150080,China 2.department of Applied Physics,{2.,harbin 150001,China)

The optical limiting (OL) characteristics of a new hexagonal prism shaped metal cluster compound (W2.g4S8(dppy)4) in N,N-dimethyllformaide (DMF) were investigated by using nanosecond (ns) and picosecond (ps) laser pulses at 53. nm, respectively. experimental results show that OL characteristic of nanosecond for the metal cluster compound is better than that of picosecond. Time-resolved pump-probe test for W2.g4S8(dppy)4 was performed with 40 ps laser pulses under two different pump energy at 53. nm to analyse its OL mechanism. experimental results indicate that its dominant OL mechanism is nonlinear absorption under picosecond laser pulses while under nanosecond laser pulses its dominant OL mechanism is the cooperation of nonlinear absorption and nonlinear scattering which results from nonlinear absorption.

关键词： Optical limiting Metal clusters Pump-probe

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