Crystal growth is a complicated phase transition process.A perfect mechanism for practical crystal growth process has not been proposed and well recognized up till now.A model,i.e.screw dislocation model presented by ...Crystal growth is a complicated phase transition process.A perfect mechanism for practical crystal growth process has not been proposed and well recognized up till now.A model,i.e.screw dislocation model presented by F.C.Frank for imperfect crystal growth was adopted during early 1950’s.No systemic research on defects other than screw dislocation has been conducted during a quite long time. Since 1980’s,we have engaged systematically in the investigation of the defect mechanism of crystal growth,and our conclusion is that any defect providing step sources in the growing surface can make contribution to continuous crystal growth.These steps contain both complete(whole)steps and sub steps(incomplete steps).展开更多
To balance the convergence rate and steadystate error of blind source separation(BSS) algorithms, an efficient equivariant adaptive separation via independence(Efficient EASI) algorithm is proposed based on separating...To balance the convergence rate and steadystate error of blind source separation(BSS) algorithms, an efficient equivariant adaptive separation via independence(Efficient EASI) algorithm is proposed based on separating indicator, which was derived from the convergence condition of EASI, and can be used to evaluate the separation degree of separated signals. Furthermore, a nonlinear monotone increasing function between suitable step sizes and separating indicator is constructed to adaptively adjust step sizes, and forgetting factor is employed to weaken effects of data at the initial stage. Numerical case studies and experimental studies on a test bed with shell structures are provided to validate the efficiency improvement of the proposed method. This study can benefit for vibration & acoustic monitoring and control, and machinery condition monitoring and fault diagnosis.展开更多
文摘Crystal growth is a complicated phase transition process.A perfect mechanism for practical crystal growth process has not been proposed and well recognized up till now.A model,i.e.screw dislocation model presented by F.C.Frank for imperfect crystal growth was adopted during early 1950’s.No systemic research on defects other than screw dislocation has been conducted during a quite long time. Since 1980’s,we have engaged systematically in the investigation of the defect mechanism of crystal growth,and our conclusion is that any defect providing step sources in the growing surface can make contribution to continuous crystal growth.These steps contain both complete(whole)steps and sub steps(incomplete steps).
基金supported by the National Natural Science Foundation of China(Grant No.51305329)the China Postdoctoral Science Foundation(Grant No.2014T70911)+1 种基金the Doctoral Foundation of Education Ministry of China(Grant No.20130201120040)Basic Research Project of Natural Science in Shaanxi Province(Grant No.2015JQ5183)
文摘To balance the convergence rate and steadystate error of blind source separation(BSS) algorithms, an efficient equivariant adaptive separation via independence(Efficient EASI) algorithm is proposed based on separating indicator, which was derived from the convergence condition of EASI, and can be used to evaluate the separation degree of separated signals. Furthermore, a nonlinear monotone increasing function between suitable step sizes and separating indicator is constructed to adaptively adjust step sizes, and forgetting factor is employed to weaken effects of data at the initial stage. Numerical case studies and experimental studies on a test bed with shell structures are provided to validate the efficiency improvement of the proposed method. This study can benefit for vibration & acoustic monitoring and control, and machinery condition monitoring and fault diagnosis.
