A methodology for alignment of an X-ray image and a CT image, based on the Chamfer 3-4 distance transform and simulated annealing optimization algorithm is presented. Firstly, an initial transformation matrix is const...A methodology for alignment of an X-ray image and a CT image, based on the Chamfer 3-4 distance transform and simulated annealing optimization algorithm is presented. Firstly, an initial transformation matrix is constructed. For the convenience of computing, geometric models of the X-ray device to reconstruct the calibration matrix are used. Then, by defining the distance between the 3-D protective and the 2-D object image, we optimize this distance matching problem, using the simulated annealing algorithm. This method is also integrated into medical intra-operation, dealing with the data set acquired from 3-D image workstation and active navigation.展开更多
This paper has been done on study kinematic problem of Persian joint in a general way. In this study, instead of using simulation analysis method as in the previous researches, the 3D rotation matrix method is applied...This paper has been done on study kinematic problem of Persian joint in a general way. In this study, instead of using simulation analysis method as in the previous researches, the 3D rotation matrix method is applied to present the relationship of angular velocities of input shaft and output shaft. The result shows that when the angle between intersecting shafts changes from 0 to 135°, the angular velocity is maintained constant. This new result completely matches with analysis from kinematic simulation of this mechanism. The obtained result is an important base to solve dynamic problem in order to develop the applicability of this joint in reality.展开更多
In this paper, the principle of multi-point forming (MPF) technique is presented. One of the most serious defects, wrinkling, during the multi-point forming process of a shallow rectangle cup is discussed by means of ...In this paper, the principle of multi-point forming (MPF) technique is presented. One of the most serious defects, wrinkling, during the multi-point forming process of a shallow rectangle cup is discussed by means of numerical simulation on the shallow rectangle cup forming process. The effects of thickness, material of sheet metal and the pressure of the blank holder are investigated. Based on the simulation results, the reasons and control methods of wrinkling are pointed out. Moreover, the experiment on the multi-point die forming of the shallow rectangle cup by the MPF machine is done to validate the efficiency of the numerical simulation, and the result proves that the application of an elastic cushion in the forming can restrain wrinkling efficiently.展开更多
The MacCormack method is applied to the analysis of multiconductor transmission lines by intro- ducing a new technique that does not require decoupling. This method can be used to analyze a wide range of problems and ...The MacCormack method is applied to the analysis of multiconductor transmission lines by intro- ducing a new technique that does not require decoupling. This method can be used to analyze a wide range of problems and does not have to consider the matrix forms of distributed parameters. We have developed soft- ware named MacCormack Transmission Line Analyzer based on the proposed method. Numerical examples are presented to demonstrate the accuracy and efficiency of the method and illustrate its application to analyz- ing multiconductor transmission lines.展开更多
There is little low-and-high frequency information on seismic data in seismic exploration,resulting in narrower bandwidth and lower seismic resolution.It considerably restricts the prediction accuracy of thin reservoi...There is little low-and-high frequency information on seismic data in seismic exploration,resulting in narrower bandwidth and lower seismic resolution.It considerably restricts the prediction accuracy of thin reservoirs and thin interbeds.This study proposes a novel method to constrain improving seismic resolution in the time and frequency domain.The expected wavelet spectrum is used in the frequency domain to broaden the seismic spectrum range and increase the octave.In the time domain,the Frobenius vector regularization of the Hessian matrix is used to constrain the horizontal continuity of the seismic data.It eff ectively protects the signal-to-noise ratio of seismic data while the longitudinal seismic resolution is improved.This method is applied to actual post-stack seismic data and pre-stack gathers dividedly.Without abolishing the phase characteristics of the original seismic data,the time resolution is signifi cantly improved,and the structural features are clearer.Compared with the traditional spectral simulation and deconvolution methods,the frequency distribution is more reasonable,and seismic data has higher resolution.展开更多
Transport of nanoparticles and coagulation is simulated with the combination of CFD in a circular bend. The Taylor-expansion moment method(TEMOM)is employed to study dynamics of nanoparticles with Brownian motion,base...Transport of nanoparticles and coagulation is simulated with the combination of CFD in a circular bend. The Taylor-expansion moment method(TEMOM)is employed to study dynamics of nanoparticles with Brownian motion,based on the flow field from numerical simulation.A fully developed flow pattern in the present simulation is compared with previous numerical results for validating the model and computational code.It is found that for the simulated particulate flow system,the particle mass concentration,number concentration,particle polydispersity, mean particle diameter and geometric standard deviation over cross-section increase with time.The distribution of particle mass concentration at different time is independent of the initial particle size.More particles are concen-trated at outer edge of the bend.Coagulation plays more important role at initial stage than that in the subsequent period.The increase of Reynolds number and initial particle size leads to the increase of particle number concentration.The particle polydispersity,mean particle diameter and geometric standard deviation increase with decreasing Reynolds number and initial particle size.展开更多
This paper presents an analog circuit built-in-test （BIT） structure based on boundary scan and realizes the BI＇I. It predigests the test process and improves the test precision by taking the rectangular pulse as st...This paper presents an analog circuit built-in-test （BIT） structure based on boundary scan and realizes the BI＇I. It predigests the test process and improves the test precision by taking the rectangular pulse as stimulator and analog switch as auxiliary bridge. The experiment of uA741 shows that the design is feasible. Compared with the traditional test method, it is better regarding reliability and measurability of the analog circuit system.展开更多
基金The National Natural Science Foundation of China (60272045) the Key Project of Ministry of Education of China.
文摘A methodology for alignment of an X-ray image and a CT image, based on the Chamfer 3-4 distance transform and simulated annealing optimization algorithm is presented. Firstly, an initial transformation matrix is constructed. For the convenience of computing, geometric models of the X-ray device to reconstruct the calibration matrix are used. Then, by defining the distance between the 3-D protective and the 2-D object image, we optimize this distance matching problem, using the simulated annealing algorithm. This method is also integrated into medical intra-operation, dealing with the data set acquired from 3-D image workstation and active navigation.
文摘This paper has been done on study kinematic problem of Persian joint in a general way. In this study, instead of using simulation analysis method as in the previous researches, the 3D rotation matrix method is applied to present the relationship of angular velocities of input shaft and output shaft. The result shows that when the angle between intersecting shafts changes from 0 to 135°, the angular velocity is maintained constant. This new result completely matches with analysis from kinematic simulation of this mechanism. The obtained result is an important base to solve dynamic problem in order to develop the applicability of this joint in reality.
文摘In this paper, the principle of multi-point forming (MPF) technique is presented. One of the most serious defects, wrinkling, during the multi-point forming process of a shallow rectangle cup is discussed by means of numerical simulation on the shallow rectangle cup forming process. The effects of thickness, material of sheet metal and the pressure of the blank holder are investigated. Based on the simulation results, the reasons and control methods of wrinkling are pointed out. Moreover, the experiment on the multi-point die forming of the shallow rectangle cup by the MPF machine is done to validate the efficiency of the numerical simulation, and the result proves that the application of an elastic cushion in the forming can restrain wrinkling efficiently.
文摘The MacCormack method is applied to the analysis of multiconductor transmission lines by intro- ducing a new technique that does not require decoupling. This method can be used to analyze a wide range of problems and does not have to consider the matrix forms of distributed parameters. We have developed soft- ware named MacCormack Transmission Line Analyzer based on the proposed method. Numerical examples are presented to demonstrate the accuracy and efficiency of the method and illustrate its application to analyz- ing multiconductor transmission lines.
基金supported by the PetroChina Prospective,Basic,and Strategic Technology Research Project(No.2021DJ0606).
文摘There is little low-and-high frequency information on seismic data in seismic exploration,resulting in narrower bandwidth and lower seismic resolution.It considerably restricts the prediction accuracy of thin reservoirs and thin interbeds.This study proposes a novel method to constrain improving seismic resolution in the time and frequency domain.The expected wavelet spectrum is used in the frequency domain to broaden the seismic spectrum range and increase the octave.In the time domain,the Frobenius vector regularization of the Hessian matrix is used to constrain the horizontal continuity of the seismic data.It eff ectively protects the signal-to-noise ratio of seismic data while the longitudinal seismic resolution is improved.This method is applied to actual post-stack seismic data and pre-stack gathers dividedly.Without abolishing the phase characteristics of the original seismic data,the time resolution is signifi cantly improved,and the structural features are clearer.Compared with the traditional spectral simulation and deconvolution methods,the frequency distribution is more reasonable,and seismic data has higher resolution.
基金Supported by the Major Program of the National Natural Science Foundation of China（10632070）
文摘Transport of nanoparticles and coagulation is simulated with the combination of CFD in a circular bend. The Taylor-expansion moment method(TEMOM)is employed to study dynamics of nanoparticles with Brownian motion,based on the flow field from numerical simulation.A fully developed flow pattern in the present simulation is compared with previous numerical results for validating the model and computational code.It is found that for the simulated particulate flow system,the particle mass concentration,number concentration,particle polydispersity, mean particle diameter and geometric standard deviation over cross-section increase with time.The distribution of particle mass concentration at different time is independent of the initial particle size.More particles are concen-trated at outer edge of the bend.Coagulation plays more important role at initial stage than that in the subsequent period.The increase of Reynolds number and initial particle size leads to the increase of particle number concentration.The particle polydispersity,mean particle diameter and geometric standard deviation increase with decreasing Reynolds number and initial particle size.
文摘This paper presents an analog circuit built-in-test （BIT） structure based on boundary scan and realizes the BI＇I. It predigests the test process and improves the test precision by taking the rectangular pulse as stimulator and analog switch as auxiliary bridge. The experiment of uA741 shows that the design is feasible. Compared with the traditional test method, it is better regarding reliability and measurability of the analog circuit system.
