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DIGITAL SPECKLE CORRELATION METHOD IMPROVED BY GENETIC ALGORITHM 被引量:27
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作者 MaShaopeng JillGuanchang 《Acta Mechanica Solida Sinica》 SCIE EI 2003年第4期366-373,共8页
The digital speckle correlation method is an important optical metrology for sur- face displacement and strain measurement.With this technique,the whole field deformation in- formation can be obtained by tracking the ... The digital speckle correlation method is an important optical metrology for sur- face displacement and strain measurement.With this technique,the whole field deformation in- formation can be obtained by tracking the geometric points on the speckle images based on a correlation-matching search technique.However,general search techniques suffer from great com- putational complexity in the processing of speckle images with large deformation and the large random errors in the processing of images of bad quality.In this paper,an advanced approach based on genetic algorithms (GA) for correlation-matching search is developed.Benefiting from the abilities of global optimum and parallelism searching of GA,this new approach can complete the correlation-matching search with less computational consumption and at high accuracy.Two experimental results from the simulated speckle images have proved the efficiency of the new approach. 展开更多
关键词 digital speckle correlation method genetic algorithm deformation measurement
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Deformation Field around the Stress Induced Crack Area in Sandstone by the Digital Speckle Correlation Method 被引量:4
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作者 ZHAO Yonghong MA Shaopeng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2009年第3期661-672,共12页
The deformation field around sub-cracks was calculated using the digital speckle correlation method. First, the uni-axial compression tests on sandstone samples containing a pre- fabricated fracture were made. Photomi... The deformation field around sub-cracks was calculated using the digital speckle correlation method. First, the uni-axial compression tests on sandstone samples containing a pre- fabricated fracture were made. Photomicrographs showing the characteristics of the sub-crack development were taken using a scanning electron microscope (SEM). From these photomicrographs, the real-time images showing the initiation, growth and coalescence of sub-cracks and micro-cracks in the sandstone specimens were obtained and the effects of loading level as well as grain boundaries on the development of cracks were analyzed. Second, the intensity images of the sandstone specimen surface were captured from the observations of the SEM corresponding to different loading levels. Then correlation computation was carried out for the sequential pairs of intensity images to evaluate the displacement components, as well as the strain field. The results show that the deformation varies in different areas separated by sub-cracks during rock damage processes. 展开更多
关键词 SANDSTONE sub-crack in rock scanning electron microscopy observation displacementfield digital speckle correlation method rock mechanics
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Experimental investigation of interface curing stresses between PMMA and composite using digital speckle correlation method 被引量:4
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作者 Yinji Ma,Tiechui Xiong,and Xuefeng Yao Department of Engineering Mechanics,Applied Mechanics Laboratory,Tsinghua University,Beijing 100084,China 《Theoretical & Applied Mechanics Letters》 CAS 2011年第5期14-17,共4页
This paper studies the interface curing stresses between polymethyl methacrylate (PMMA) and composite by means of digital speckle correlation method (DSCM).A new method by combining DSCM with the marker points is deve... This paper studies the interface curing stresses between polymethyl methacrylate (PMMA) and composite by means of digital speckle correlation method (DSCM).A new method by combining DSCM with the marker points is developed to measure the interface curing stresses,and the measurement principle is introduced.The interface curing stresses between PMMA and composite with different curing bonding conditions are measured and analyzed,this indicates that the residual stress for furnace heating and furnace cooling is the smallest.Finally,the measurement error is discussed by means of finite element method,the influences of glass microsphere between adhesive and PMMA can be ignored. 展开更多
关键词 interface stress CURE adhesive layer digital speckle correlation method
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Characterization for elastic constants of fused deposition modelling-fabricated materials based on the virtual fields method and digital image correlation 被引量:3
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作者 Quankun Cao Huimin Xie 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2017年第6期1075-1083,共9页
Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials ... Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials is proposed. First of all, according to the manufacturing process of FDM, orthotropic constitutive model is used to describe the mechanical behavior. Then the virtual fields method(VFM) is applied to characterize all the mechanical parameters(Q, Q, Q, Q) using the full-field strain,which is measured by digital image correlation(DIC). Since the principal axis of the FDM-fabricated structure is sometimes unknown due to the complexity of the manufacturing process, a disk in diametrical compression is used as the load configuration so that the loading angle can be changed conveniently. To verify the feasibility of the proposed method, finite element method(FEM) simulation is conducted to obtain the strain field of the disk. The simulation results show that higher accuracy can be achieved when the loading angle is close to 30?. Finally, a disk fabricated by FDM was used for the experiment. By rotating the disk, several tests with different loading angles were conducted. To determine the position of the principal axis in each test, two groups of parameters(Q, Q, Q, Q) are calculated by two different groups of virtual fields. Then the corresponding loading angle can be determined by minimizing the deviation between two groups of the parameters. After that, the four constants(Q, Q, Q, Q) were determined from the test with an angle of 27?. 展开更多
关键词 Fused deposition modelling Virtual fields method Digital image correlation Orthotropic constitutive model Disk compression
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Correlation method estimation of the modulation signal in the weak equivalence principle test 被引量:1
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作者 Jie Luo Liang-Cheng Shen +2 位作者 Cheng-Gang Shao Qi Liu Hui-Jie Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第8期136-142,共7页
In a test of the weak equivalence principle (WEP) with a rotating torsion pendulum, it is important to estimate the amplitude of the modulation signal with high precision. We use a torsional filter to remove the fre... In a test of the weak equivalence principle (WEP) with a rotating torsion pendulum, it is important to estimate the amplitude of the modulation signal with high precision. We use a torsional filter to remove the free oscillation signal and employ the correlation method to estimate the amplitude of the modulation signal. The data analysis of an experiment shows that the uncertainties of amplitude components of the modulation signal obtained by the correlation method are in agreement with those due to white noise. The power spectral density of the modulation signal obtained by the correlation method is about one order higher than the thermal noise limit. It indicates that the correlation method is an effective way to estimate the amplitude of the modulation signal and it is instructive to conduct a high-accuracy WEP test. 展开更多
关键词 weak equivalence principle test correlation method amplitude estimation thermal noise limit
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Correlations between direct and indirect strength test methods 被引量:3
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作者 Kallu Raj Roghanchi Pedram 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第3期355-360,共6页
The difficulties associated with performing direct compression strength tests on rocks lead to the development of indirect test methods for the rock strength assessment. Indirect test methods are simple, more economic... The difficulties associated with performing direct compression strength tests on rocks lead to the development of indirect test methods for the rock strength assessment. Indirect test methods are simple, more economical, less time-consuming, and easily adaptable to the field. The main aim of this study was to derive correlations between direct and indirect test methods for basalt and rhyolite rock types from Carlin trend deposits in Nevada. In the destructive methods, point load index, block punch index, and splitting tensile strength tests are performed. In the non-destructive methods, Schmidt hammer and ultrasonic pulse velocity tests are performed. Correlations between the direct and indirect compression strength tests are developed using linear and nonlinear regression analysis methods. The results show that the splitting tensile strength has the best correlation with the uniaxial compression strength.Furthermore, the Poisson's ratio has no correlation with any of the direct and indirect test results. 展开更多
关键词 Uniaxial compression strength test Indirect strength test methods correlation Regression analysis
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Tensile strength of sea ice using splitting tests based on the digital image correlation method 被引量:1
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作者 CHEN Xiaodong HE Shuaikang +2 位作者 HE Wenquan WANG Zhaoyu JI Shunying 《Advances in Polar Science》 CSCD 2021年第4期374-381,共8页
The splitting test is a competitive alternative method to study the tensile strength of sea ice owing to its suitability for sampling.However,the approach was questioned to the neglect of local plastic deformation dur... The splitting test is a competitive alternative method to study the tensile strength of sea ice owing to its suitability for sampling.However,the approach was questioned to the neglect of local plastic deformation during the tests.In this study,splitting tests were performed on sea ice,with 32 samples subjected to the regular procedure and 8 samples subjected to the digital image correlation method.The salinity,density,and temperature were measured to determine the total porosity.With the advantage of the digital image correlation method,the full-field deformation of the ice samples could be determined.In the loading direction,the samples mainly deformed at the ice-platen contact area.In the direction vertical to the loading,deformation appears along the central line where the splitting crack occurs.Based on the distribution of the sample deformation,a modified solution was derived to calculate the tensile strength with the maximum load.Based on the modified solution,the tensile strength was further calculated together with the splitting test results.The results show that the tensile strength has a negative correlation with the total porosity,which agrees with previous studies based on uniaxial tension tests. 展开更多
关键词 tensile strength splitting test digital image correlation method ice mechanics sea ice
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Correction of cosine oscillation to the improved correlation method of estimating the amplitude of gravitational background signal
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作者 巫伟皇 田苑 +2 位作者 薛超 罗杰 邵成刚 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第4期122-131,共10页
In the measurement of G with the angular acceleration method,the improved correlation method developed by Wu et al.(Wu W H,Tian Y,Luo J,Shao C G,Xu J H and Wang DH 2016 Rev.Sci.Instrum.87 094501) is used to accurate... In the measurement of G with the angular acceleration method,the improved correlation method developed by Wu et al.(Wu W H,Tian Y,Luo J,Shao C G,Xu J H and Wang DH 2016 Rev.Sci.Instrum.87 094501) is used to accurately estimate the amplitudes of the prominent harmonic components of the gravitational background signal with time-varying frequency.Except the quadratic slow drift,the angular frequency of the gravitational background signal also includes a cosine oscillation coming from the useful angular acceleration signal,which leads to a deviation from the estimated amplitude.We calculate the correction of the cosine oscillation to the amplitude estimation.The result shows that the corrections of the cosine oscillation to the amplitudes of the fundamental frequency and second harmonic components obtained by the improved correlation method are within respective errors. 展开更多
关键词 gravitational background signal improved correlation method CORRECTION cosine oscillation
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Correlation Method of Average Plasma Velocity Measurement in Hall-Effect Thrusters
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作者 宁中喜 李鸿 于达仁 《Plasma Science and Technology》 SCIE EI CAS CSCD 2009年第6期709-713,共5页
A new method to measure the average plasma velocity in a Hall-effect thruster is presented. The method is brought forward in virtue of the characteristics of low frequency oscillation induced by the propellant ionizat... A new method to measure the average plasma velocity in a Hall-effect thruster is presented. The method is brought forward in virtue of the characteristics of low frequency oscillation induced by the propellant ionization in the channel and the oriented movement feature of the plasma density out of the channel. The method, equivalent to the correlation method generally used in the signal processing field, provides a solution to the problem of specific impulse measurement on a timescale of hundreds of microseconds and makes the time evolution of average plasma velocity clear. The comparison between the measured value and the calibrated value shows that the relative error is about 3%. 展开更多
关键词 Hall-effect thruster average plasma velocity correlation method
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Correlation of Evaluation Methods on Boar Semen Quality
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作者 WU Cai-hong YAO Jing +4 位作者 ZHANG Bin FU Hai-ke YANG Zhi-fen LI Kai SHENG Qiang 《Animal Husbandry and Feed Science》 CAS 2013年第5期232-235,共4页
To explore the correlation of evaluation methods on boar semen quality, the motility, PI staining, hypotonic swelling test, Rh123 staining and FITC- PNA staining of boar sperm were checked in the study, and its correl... To explore the correlation of evaluation methods on boar semen quality, the motility, PI staining, hypotonic swelling test, Rh123 staining and FITC- PNA staining of boar sperm were checked in the study, and its correlation with IVF was statistically calculated. The results showed that various indicators had strong linear correlation with each other, and the correlation degree between acrosome integrity and IVF rate was the highest, indicating that acrosome integrity was supedor to other indicators in predicting IVF rate. 展开更多
关键词 BOAR SEMEN Evaluation method correlation
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A Simple Superresolution Approach of Multipath Delay Profiles Measured by PN Correlation Method
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作者 唐敖 倪滨 龚克 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2001年第4期13-16,共4页
Time resolution of multipath delay profiles measured by using autocorrelation of pseudonoise (PN) code sequence is generally limited by the chip rate of the PN code sequence. In this paper, we propose a simple method ... Time resolution of multipath delay profiles measured by using autocorrelation of pseudonoise (PN) code sequence is generally limited by the chip rate of the PN code sequence. In this paper, we propose a simple method to improve the time resolution of delay profiles measured by the PN correlation method. Effectiveness of this method is demonstrated by indoor wireless propagation experiments. 展开更多
关键词 Communication channels (information theory) CONVOLUTION correlation methods Radio communication Signal distortion Spurious signal noise
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Study on Correlation and Quantiative Error Estimation Method Among the Splitting Shear Wave Identification Methods
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作者 Liu Xiqiang Zhou Huilan +1 位作者 Li Hong Gai Dianguang 《Earthquake Research in China》 2000年第3期53-62,共10页
Based on the propagation characteristics of shear wave in the anisotropic layers,thecorrelation among several splitting shear-wave identification methods hasbeen studied.Thispaper puts forward the method estimating sp... Based on the propagation characteristics of shear wave in the anisotropic layers,thecorrelation among several splitting shear-wave identification methods hasbeen studied.Thispaper puts forward the method estimating splitting shear-wave phases and its reliability byusing of the assumption that variance of noise and useful signal data obey normaldistribution.To check the validity of new method,the identification results and errorestimation corresponding to 95% confidence level by analyzing simulation signals have beengiven. 展开更多
关键词 ANISOTROPY SHEAR-WAVE SPLITTING Identification methods correlation ERROR estimation
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Application Study on Rigidity Correlation Method for Density Inversion of Rockfill
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作者 Pan Liu Mingjie Zhao +2 位作者 Bowen Jiang Kui Wang Peng Jin 《Engineering(科研)》 2015年第6期331-336,共6页
Based on the theoretical model of rigidity correlation method, the study on application was carried out with Chinese Liyuan face rockfill dam as example. The linear relation equations between the rockfill rigidity and... Based on the theoretical model of rigidity correlation method, the study on application was carried out with Chinese Liyuan face rockfill dam as example. The linear relation equations between the rockfill rigidity and density measured by pit method were established, and the regression performance and accuracy of rigidity correlation method were analyzed by calculating the inversion values of density. The results show that the regression equations of rigidity correlation method are high significant so as to work out the rockfill density precisely;rigidity correlation method is used for density inversion of rockfill with minor error and namely high accuracy, which is proper with satisfactory results. 展开更多
关键词 RIGIDITY correlation method ROCKFILL DENSITY INVERSION Regression Performance ACCURACY
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2-11 Decay Studies of 213Rn Using Implantation-r-a Correlation Method
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作者 Huang Tianheng Liu Zhong +2 位作者 Sun Mingdao Ding Bing Zhang Wenqiang 《IMP & HIRFL Annual Report》 2015年第1期65-65,共1页
The region around the double-closed shell nucleus 208Pb has been particularly useful in studying residual interactions. The low spin isomers of the isotopes in the N=127, Z=8387 region have been identified in lastfif... The region around the double-closed shell nucleus 208Pb has been particularly useful in studying residual interactions. The low spin isomers of the isotopes in the N=127, Z=8387 region have been identified in lastfifty years except 213Rn[1??4]. In our recent implantation–r-a correlation study of the isotopes around the N=126 shell closure, a new ray is observed between the implantations and the decays of 213Rn, which could be due to the depopulation of the isomer of 213Rn mentioned above. 展开更多
关键词 Implantation-r-a correlation method
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Long memory of price-volume correlation in metal futures market based on fractal features 被引量:3
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作者 程慧 黄健柏 +1 位作者 郭尧琦 朱学红 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第10期3145-3152,共8页
An empirical test on long memory between price and trading volume of China metals futures market was given with MF-DCCA method. The empirical results show that long memory feature with a certain period exists in price... An empirical test on long memory between price and trading volume of China metals futures market was given with MF-DCCA method. The empirical results show that long memory feature with a certain period exists in price-volume correlation and a fittther proof was given by analyzing the source of multifractal feature. The empirical results suggest that it is of important practical significance to bring the fractal market theory and other nonlinear theory into the analysis and explanation of the behavior in metal futures market. 展开更多
关键词 metal futures price-volume correlation long memory MF-DCCA method MULTIFRACTAL fractal features multifractalspectrum
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Initial estimation of hydrate formation temperature of sweet natural gases based on new empirical correlation 被引量:6
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作者 Mohammad Mahdi Ghiasi 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2012年第5期508-512,共5页
Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz... Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz gas gravity method can be used for initial estimation of hydrate formation temperature (HFT) under the circumstances of indeterminate gas composition.So far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and Vuthaluru.The main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity chart.By reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range. 展开更多
关键词 natural gas hydrates hydrate formation temperature gas gravity method empirical correlation
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Reliability Distribution of Numerical Control Lathe Based on Correlation Analysis 被引量:3
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作者 Xiaoyan Qi Guixiang Shen +2 位作者 Yingzhi Zhang Shuguang Sun Bingkun Chen 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2016年第5期32-38,共7页
Combined Reliability distribution with correlation analysis,a new method has been proposed to make Reliability distribution where considering the elements about structure correlation and failure correlation of subsyst... Combined Reliability distribution with correlation analysis,a new method has been proposed to make Reliability distribution where considering the elements about structure correlation and failure correlation of subsystems.Firstly,we make a sequence for subsystems by means of TOPSIS which comprehends the considerations of Reliability allocation,and introducing a Copula connecting function to set up a distribution model based on structure correlation,failure correlation and target correlation,and then acquiring reliability target area of all subsystems by Matlab.In this method,not only the traditional distribution considerations are concerned,but also correlation influences are involved,to achieve supplementing information and optimizing distribution. 展开更多
关键词 RELIABILITY DISTRIBUTION correlation analysis TOPSIS method COPULA connecting FUNCTION
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Age trends and correlations of growth and wood properties in clone of Eucalyptus urophylla × E. grandis in Guangdong, China 被引量:3
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作者 WU Shi-jun XU Jian-min +3 位作者 LI Guang-you Du Zhi-hu LU Zhao-hua LI Bao-qi 《Journal of Forestry Research》 CAS CSCD 2012年第3期467-472,共6页
We assessed growth traits and wood properties ofDH32-29, a clone of Eucalyptus urophylla x E. grandis, at age of two to six years in Guangdong in China. Analysis of variance of studied traits showed that there were si... We assessed growth traits and wood properties ofDH32-29, a clone of Eucalyptus urophylla x E. grandis, at age of two to six years in Guangdong in China. Analysis of variance of studied traits showed that there were significant differences (1% level) on all studied traits among ages except for wood basic density. Analysis of age trends of growth traits and wood properties revealed that rotation length of DH32-29 should be more than six years or longer. Phenotypic correlations among traits at individual ages indicated that correlations between growth traits were strongly positive. There was significant change in relationship between growth and wood basic density with increasing age, ranging from -0.03 to -0.54 at 2 and 5 year and 0.003 to 0.3 at 3, 4 and 6 year. Correlations between Pilodyn pin penetration and basic density measured on increment cores showed that Pilodyn could rank or group genotypes or sites into density classes, but failure to predict individual tree and individual clone. 展开更多
关键词 EUCALYPT age trends growth traits wood properties correlation nondestructive methods
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Reliability Sensitivity-based Correlation Coefficient Calculation in Structural Reliability Analysis 被引量:11
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作者 YANG Zhou ZHANG Yimin +1 位作者 ZHANG Xufang HUANG Xianzhen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第3期608-614,共7页
The correlation coefficients of random variables of mechanical structures are generally chosen with experience or even ignored,which cannot actually reflect the effects of parameter uncertainties on reliability.To dis... The correlation coefficients of random variables of mechanical structures are generally chosen with experience or even ignored,which cannot actually reflect the effects of parameter uncertainties on reliability.To discuss the selection problem of the correlation coefficients from the reliability-based sensitivity point of view,the theory principle of the problem is established based on the results of the reliability sensitivity,and the criterion of correlation among random variables is shown.The values of the correlation coefficients are obtained according to the proposed principle and the reliability sensitivity problem is discussed.Numerical studies have shown the following results:(1) If the sensitivity value of correlation coefficient ρ is less than(at what magnitude 0.000 01),then the correlation could be ignored,which could simplify the procedure without introducing additional error.(2) However,as the difference between ρs,that is the most sensitive to the reliability,and ρR,that is with the smallest reliability,is less than 0.001,ρs is suggested to model the dependency of random variables.This could ensure the robust quality of system without the loss of safety requirement.(3) In the case of |Eabs|ρ0.001 and also |Erel|ρ0.001,ρR should be employed to quantify the correlation among random variables in order to ensure the accuracy of reliability analysis.Application of the proposed approach could provide a practical routine for mechanical design and manufactory to study the reliability and reliability-based sensitivity of basic design variables in mechanical reliability analysis and design. 展开更多
关键词 structural reliability reliability sensitivity probabilistic perturbation method selection of the correlation coefficient
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Effects of electron correlation and the Breit interaction on one- and two-electron one-photon transitions in double K hole states of He-like ions(10 ≤ Z ≤ 47) 被引量:1
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作者 Xiaobin Ding Cunqiang Wu +5 位作者 Mingxin Cao Denghong Zhang Mingwu Zhang Yingli Xue Deyang Yu Chenzhong Dong 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第3期148-155,共8页
The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s^2 configurations of 11 selected He-like ions(10 ≤ Z ≤ 47)... The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s^2 configurations of 11 selected He-like ions(10 ≤ Z ≤ 47) are calculated using the fully relativistic multi-configuration Dirac–Fock method(MCDF). An appropriate electron correlation model is constructed with the aid of the active space method, which allows the electron correlation effects to be studied efficiently. The contributions of the electron correlation and the Breit interaction to the transition properties are analyzed in detail. It is found that the two-electron one-photon(TEOP) transition is correlation sensitive. The Breit interaction and electron correlation both contribute significantly to the radiative transition properties of the double K hole state of the He-like ions. Good agreement between the present calculation and previous work is achieved. The calculated data will be helpful to future investigations on double K hole decay processes of He-like ions. 展开更多
关键词 electron correlation multi-configuration Dirac–Fock method(MCDF) DOUBLE K hole state two-electron one-photon(TEOP)transition
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