Compositionally undulating step-graded Al（Ga）InxAs （x = 0.05-0.52） buffers with the following InP layer were grown by metal-organic chemical vapor deposition （MOCVD） on （001） GaAs with a 15° miscut. The d...Compositionally undulating step-graded Al（Ga）InxAs （x = 0.05-0.52） buffers with the following InP layer were grown by metal-organic chemical vapor deposition （MOCVD） on （001） GaAs with a 15° miscut. The dislocation dis- tribution and tilts of the epilayers were examined using x-ray rocking curve and （004） reciprocal space maps （RSM） along two orthogonal （110） directions. The results suggested that such reverse-graded layers have different effects on a and 13 dislocations. A higher dislocation density was observed along the [ 110] direction and an epilayer tilt of - 1.43° was attained in the [1-10] direction when a reverse-graded layer strategy was employed. However, for conventional step-graded samples, the dislocation density is normally higher along the [1-10] direction.展开更多
Dislocation distribution functions of the edges of mode Ⅲ propagation crack subjected to three types of loads were studied by the methods of the theory of complex variable functions,by which,the problems researched w...Dislocation distribution functions of the edges of mode Ⅲ propagation crack subjected to three types of loads were studied by the methods of the theory of complex variable functions,by which,the problems researched were facilely transformed into Riemann-Hilbert problems and Keldysh-Sedov mixed boundary value problems. Analytical solutions of stresses,displacement and dynamic stress intensity factor were obtained by the measures of the theory of self-similar functions and corresponding differential and integral operation. In terms of the relationship between dislocation distribution functions and displacements,analytical solutions of dislocation distribution functions were obttained,and variational rules of dislocation distribution functions were depicted.展开更多
This paper presents a numerical solution to model multiple cracks in a finite plate of an elastic isotropic material. Both the boundaries and the cracks are modeled by distributed dislocations. This method results in ...This paper presents a numerical solution to model multiple cracks in a finite plate of an elastic isotropic material. Both the boundaries and the cracks are modeled by distributed dislocations. This method results in a system of singular integral equations with Cauchy kernels which can be solved by Gauss-Chebyshev quadrature method. Four examples are provided to assess the capability of this method.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61376065)
文摘Compositionally undulating step-graded Al（Ga）InxAs （x = 0.05-0.52） buffers with the following InP layer were grown by metal-organic chemical vapor deposition （MOCVD） on （001） GaAs with a 15° miscut. The dislocation dis- tribution and tilts of the epilayers were examined using x-ray rocking curve and （004） reciprocal space maps （RSM） along two orthogonal （110） directions. The results suggested that such reverse-graded layers have different effects on a and 13 dislocations. A higher dislocation density was observed along the [ 110] direction and an epilayer tilt of - 1.43° was attained in the [1-10] direction when a reverse-graded layer strategy was employed. However, for conventional step-graded samples, the dislocation density is normally higher along the [1-10] direction.
基金Sponsored by the Postdoctoral Science Fundation of China (Grant No. 200303337 )the National Natural Science Foundation of China (Grant No.30205035)
文摘Dislocation distribution functions of the edges of mode Ⅲ propagation crack subjected to three types of loads were studied by the methods of the theory of complex variable functions,by which,the problems researched were facilely transformed into Riemann-Hilbert problems and Keldysh-Sedov mixed boundary value problems. Analytical solutions of stresses,displacement and dynamic stress intensity factor were obtained by the measures of the theory of self-similar functions and corresponding differential and integral operation. In terms of the relationship between dislocation distribution functions and displacements,analytical solutions of dislocation distribution functions were obttained,and variational rules of dislocation distribution functions were depicted.
基金supported by National Natural Science Foundation of China(No.51174162)
文摘This paper presents a numerical solution to model multiple cracks in a finite plate of an elastic isotropic material. Both the boundaries and the cracks are modeled by distributed dislocations. This method results in a system of singular integral equations with Cauchy kernels which can be solved by Gauss-Chebyshev quadrature method. Four examples are provided to assess the capability of this method.
