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Theoretical analysis of natural frequency of externally prestressed concrete beam based on rigidity correction

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Journal of Pharmaceutical Analysis 2009年第1期21卷 31-35页

作者： Hui-xia Xiong1,2, Yao-ting Zhang11.School of Civil Engineering & mechanics, Huazhong University of Science and technology, Wuhan 43.074, China 2.department of Civil Engineering, Nanyang {3. of technology, Nanyang 473.04, China. School of Civil Engineering and mechanics Huazhong University of Science and Technology Wuhan 430074 China department of Civil Engineering Nanyang Institute of Technology Nanyang 473004 China

A dynamic test on externally prestressed simply supported concrete beams separately with three typical types of tendon distributions was conducted. The results show that the natural frequencies of the beams increase with the increase in the prestressing force at the tensioning stage, and the natural frequencies decrease after the cracks occur in the beams. Following the calculation formula of natural frequency of externally prestressed beam, which was reported in a literature, the natural frequencies of the experimental beams are calculated, and big errors are found between the test results and the calculated ones of natural frequency values. As a result, this paper has tried to adopt two methods to correct the rigidity parameter of the concrete beam in the formula for natural frequency calculation, and to use the corrected formula to calculate the frequencies of the experimental beams. The calculation results indicate a good consistency with the experimental ones, which verifies the feasibility of the corrected formula.

关键词： externally prestressed concrete beam natural frequency rigidity correction regression analysis

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一种电动汽车动力电池均衡控制方法的设计

上海交通大学学报 2011年第8期45卷 1186-1190页

作者：杨春雷刘志远哈尔滨工业大学控制科学与工程系哈尔滨150001

针对电动汽车动力电池均衡控制存在的问题,给出了一种通过电压变换器和恒流电路对电池进行均衡的方法.该方法能满足各单体电池间均衡要求,且可避免尖峰电压对电池冲击.对均衡控制的整体结构进行了讨论,并介绍了电压变换器设计方法.对电... 详细信息

针对电动汽车动力电池均衡控制存在的问题,给出了一种通过电压变换器和恒流电路对电池进行均衡的方法.该方法能满足各单体电池间均衡要求,且可避免尖峰电压对电池冲击.对均衡控制的整体结构进行了讨论,并介绍了电压变换器设计方法.对电池充电过程的非线性特性,给出了一种易于实现且可满足均衡控制要求的闭环反馈的电流控制方法.实验结果表明,所设计的均衡控制方法能满足动力电池均衡控制的要求.

关键词：动力电池均衡控制电压变换器闭环反馈

Corrosion behaviors and formation mechanism of chromate passive film on electroless Ni-P coating

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Corrosion behaviors and formation mechanism of chromate pass...

2009年全国电子电镀及表面处理学术交流会

作者： Songlin Mu,Ning Li,Deyu Li,Zhongli Zou (department of applied chemistry,harbin institute of technology,harbin 150001)

To develop chromium- free passivation methods for electroless Ni- P coating(ENPC),the passivation mechanism of chromate methods should be researched *** composition and corrosion properties of chromate passive film on ENPC with KCrO 3.g/l as treatment bath,are investigated in this *** morphology of ENPC and passivated ENPC is examined by scanning electronic microscopy(SEM).The corrosion properties of passivated sample are tested by electrochemical *** the chemical composition of the passive film is analyzed with X- ray photoelectron spectroscopy(XPS).SEM result shows that no obvious difference can be observed on surface *** electrochemical impedance spectroscopy(EIS) tests indicate the corrosion current of the treated sample is only 1/3. of that of blank(without treated Ni - P coating).The XPS analysis illustrates that the passive film on ENPC comprises Cr,Ni and *** the thickness of this passive film is evaluated according to sputtering rate of Ar *** analysis by high- resolution XPS spectrum shows a strange result:although the sample is treated by Cr - containing bath,the element Cr in passive film is only in the form of trivalent compounds,no hexavalent chromium can be *** to XPS results,the formation mechanism of conversion coating is discussed and it can be inferred both element Ni and element P play an important role in passivation process.

关键词： Electroless Ni-P coating Passive film XPS Formation mechanism

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染料非线性标准具的光学逻辑功能

光学学报 1985年第11期5卷 980-985页

作者：张雷李淳飞哈尔滨工业大学应用物理系

本文报道用单个充染料的非线性标准具成功地演示了五种全光学逻辑功能:与、或、与非、或非和异或。并提出了一个理论模型,根据这样模型算得的描述透射光强弛豫过程的理论曲线与实验曲线完全一致。

关键词：光学逻辑标准具光学双稳器件光学逻辑门染料染剂功能

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

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Parameter Identification of Hydraulic Low Pressure Pipeline ...

COMPUTER AIDED ANALYSIS FOR COLD ROLL FORMING THIN CHANNEL SECTION

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 harbin Heilongjiang 150001 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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Acta Metallurgica Sinica(English Letters) 2001年第2期14卷 122-126页

作者： Z. W. Han ,Y.Q. Nie, L.Q. Ren and C. Liu (Key Laboratory of Terrain Machine Bionic technology, Jilin University, Changchun 13.025, China) (mechanics {3., Jilin University, Changchun 13.025, China) (institute of Rolling Mill, Yanshan University, Qin Key Laboratory of Terrain Machine Bionic technology Jilin University mechanics department Jilin University

Cold roll forming is a complicated metal processing, and its is very difficult to simulate the forming process. Based on the Updated-Lagrange method in the deformation mechanics, an elastic-plastic large deformation spline finite strip method is developed to analyze cold roll forming of a thin channel section. The longitudinal membrane strain values on the edge of the deformed strip for four one-pass sequences in different fold angles are got. Simulated results are compared with the results from previously conducted experiments. The deviation of the simulated peak strain values is within 3.% compared with the experimental results.

关键词： Computer aided analysis Computer simulation Forming Mathematical models

稀土氧化物对Si_3._4结合SiC制品烧结过程及其性能影响

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中国稀土学报 2002年第Z2期20卷 108-111页

作者：李欣韦永德哈尔滨工业大学化学系黑龙江哈尔滨150090

对Si3.4结合SiC制品进行了掺入稀土氧化物的系统实验,并对产品进行了X射线衍射测试、常温力学性能测试和扫描电子显微镜观察。实验结果表明,稀土氧化物使Si3.4结合SiC制品的Si3.4含量提高而氮氧化合物含量明显减少,使得制品的常温抗折... 详细信息

对Si3.4结合SiC制品进行了掺入稀土氧化物的系统实验,并对产品进行了X射线衍射测试、常温力学性能测试和扫描电子显微镜观察。实验结果表明,稀土氧化物使Si3.4结合SiC制品的Si3.4含量提高而氮氧化合物含量明显减少,使得制品的常温抗折强度与抗压强度都有显著提高。最后,从烧结动力学和反应机理等方面初步探讨了掺入稀土的Si3.4结合SiC制品性能优于普通Si3.4结合SiC制品的原因。

关键词：稀土氮化硅结合碳化硅抗折强度抗压强度

Prediction on Enthalpy of Mixing for Cu-La and Pd-Sn Binary Systems

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Journal of Rare Earths 2001年第1期19卷 43-43页

作者： QIAN Yi yu 1, MA Xin 1, XUE Song bai 2, Yoshida F 3.(1. National Key Laboratory of Welding, harbin institute of technology, harbin 150001, China 2. harbin Research {3. of Welding, harbin 150080, China 3. department of Mechanical Engin National Key Laboratory of Welding Harbin Institute of Technology harbin Research institute of Welding department of Mechanical Engineering Hiroshima University Higashi-Hiroshima

Enthalpy for mixing of Cu La and Pd Sn binary systems were predicted by Miedema model. The agreement between the predicting results and the experimental data shows that such model is suitable for not only ferrous me... 详细信息

关键词： rare earths enthalpy of mixing Cu La alloy Pd Sn alloy

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激光自混合干涉仪的实验研究

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