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extended defects in hydrogen-implanted (111) silicon wafer treated by high temperature annealing process

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Science China(Physics,Mechanics & Astronomy) 2004年第6期47卷 658-663页

作者： XIAO Qinghua TU Hailing General Research Institute for Non-ferrous Metals National Engineering Research Center for Semiconductor Materials Beijing 100088 China General Research Institute for Non-ferrous Metals National Engineering Research Center for Semiconductor Materials Beijing 100088 China

High resolution transmission electron microscopy (HRTEM) has been used to investigate the extended defects induced by the interaction between hydrogen and silicon during the high temperature annealing process in the hydrogen-implanted (111) silicon wafer. It has been found that the high temperature annealing process, like the low temperature annealing process, leads to the formation of cracks. However, beneath the cracks induced by high temperature annealing, there appear many additional dislocations. Some amorphous bands have also been observed. In addition, a string of cavities, which are truncated octahedral in shape and surrounded by {111} and {100 } lattice planes, have been revealed. These cavities, some of which have amorphous inner walls, are arrayed parallel to the top surface. Between cavities, there normally appears a dislocation band.

关键词： silicon, hydrogen, high temperature annealing, extended defects.

Exact solutions of a(2+1)-dimensional extended shallow water wave equation

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Chinese Physics B 2019年第10期28卷 237-244页

作者： Feng Yuan Jing-Song He Yi Cheng School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China Institute for Advanced Study Shenzhen UniversityShenzhen 518060China

We give the bilinear form and n-soliton solutions of a（2+1）-dimensional [（2+1）-D] extended shallow water wave（eSWW） equation associated with two functions v and r by using Hirota bilinear method. We provide solitons, breathers,and hybrid solutions of them. Four cases of a crucial φ（y）, which is an arbitrary real continuous function appeared in f of bilinear form, are selected by using Jacobi elliptic functions, which yield a periodic solution and three kinds of doubly localized dormion-type solution. The first order Jacobi-type solution travels parallelly along the x axis with the velocity（3k12+ α, 0） on（x, y）-plane. If φ（y） = sn（y, 3/10）, it is a periodic solution. If φ（y） = cn（y, 1）, it is a dormion-type-Ⅰ solutions which has a maximum（3/4）k1p1 and a minimum-（3/4）k1p1. The width of the contour line is ln■. If φ（y） = sn（y, 1）, we get a dormion-type-Ⅱ solution（26） which has only one extreme value-（3/2）k1p1. The width of the contour line is ln■. If φ（y） = sn（y, 1/2）/（1 + y2）, we get a dormion-type-Ⅲ solution（21） which shows very strong doubly localized feature on（x, y） plane. Moreover, several interesting patterns of the mixture of periodic and localized solutions are also given in graphic way.

关键词： (2+1)-dimensional extended shallow water wave equation Hirota bilinear method dormion-type solution

The Use of High-Performance Fatigue Mechanics and the extended Kalman/Particle Filters,for Diagnostics and Prognostics of Aircraft Structures

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Computer Modeling in Engineering & Sciences 2015年第5期105卷 1-24页

作者： Hai-Kun Wang Robert Haynes Hong-Zhong Huang Leiting Dong Satya N.Atluri School of Mechanical Electronicand Industrial EngineeringUniversity of Electronic Science and Technology of China Center for Aerospace Research&Education University of CaliforniaIrvine Vehicle Technology Directorate US Army Research Laboratory Department of Hohai University China

In this paper,we propose an approach for diagnostics and prognostics of damaged aircraft structures,by combing high-performance fatigue mechanics with filtering ***&accurate deterministic analyses of fatigue crack propagations are carried out,by using the Finite Element Alternating Method(FEAM)for computing SIFs,and by using the newly developed Moving Least Squares(MLS)law for computing fatigue crack growth *** algorithms for simulating fatigue crack propagations are embedded in the computer program Safe-Flaw,which is called upon as a subroutine within the probabilistic framework of filter *** the extended Kalman as well as particle filters are applied in this study,to obtain the statistically optimal and semi-optimal estimates of crack lengths,from a series of noisy measurements of crack-lengths over *** the specific problem,a simple modification to the particle filter,which can drastically reduce the computational burden,is also *** on the results of such diagnostic analyses,the prognostics of aerospace structures are thereafter achieved,to estimate the probabilistic distribution of the remaining useful *** using a simple example of a single-crack near a fastener hole,we demonstrate the concept and effectiveness of the proposed *** paper thus forms the scientific foundation for the recently proposed concepts of VRAMS(Virtual Risk-Informed Agile Maneuver Sustainment)and Digital Twins of aerospace vehicles.

关键词： Diagnostics and prognostics fatigue mechanics extended Kalmanfilter particle filter

extended Phase Space in the Framework of Holography

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Communications in Theoretical Physics 2019年第5期71卷 590-598页

作者： Z.Sherkatghanad B.Mirza H.Nadi M.Rostami Department of Physics Isfahan University of Technology

We consider a holographic extended phase space in the presence of Reissner-Nordstrom-Anti-de Sitter(RNAdS) and Born-Infeld-Anti-de Sitter(BI-AdS) black holes in the bulk. In this extended phase space the cosmological constant is investigated as pressure and volume is defined as the codimension one-time slice in the bulk geometry enclosed by the minimal area appearing in the computation of the holographic entanglement entropy. These thermodynamics quantities can serve as probes of the underlying phase transition dictated by black hole thermodynamics, but do not describe different structures. We find that the isocharges on the pressure-volume plane exhibit a Van der Waals-like structure, for RN-AdS black holes in the background. For BI-AdS black holes, we observe the analogy with a Van der Waals liquid-gas system for βQ > 1/2 and Reentrant phase transition for βQ extended phase space. The same holographic thermodynamic behavior is observed when we use the fidelity susceptibility as the volume and the cosmological constant as the pressure for RN-AdS black hole in the background.

关键词： extended phase space holography entanglement entropy phase cosmology

Labeled box-particle CPHD filter for multiple extended targets tracking

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Journal of Systems Engineering and Electronics 2019年第1期30卷 57-67页

作者： ZOU Zhibin SONG Liping CHENG Xuan School of Electronic Engineering Xidian University

In multiple extended targets tracking, replacing traditional multiple measurements with a rectangular region of the nonzero volume in the state space inspired by the box-particle idea is exactly suitable to deal with extended targets, without distinguishing the measurements originating from the true targets or *** on our recent work on extended box-particle probability hypothesis density(ET-BP-PHD) filter, we propose the extended labeled box-particle cardinalized probability hypothesis density(ET-LBP-CPHD) filter, which relaxes the Poisson assumptions of the extended target probability hypothesis density(PHD) filter in target numbers, and propagates not only the intensity function but also cardinality distribution. Moreover, it provides the identity of individual target by adding labels to box-particles. The proposed filter can improve the precision of estimating target number meanwhile achieve targets' tracks. The effectiveness and reliability of the proposed algorithm are verified by the simulation results.

关键词： extended target multiple targets tracking labled boxparticle cardinalized probability hypothesis density (CPHD).

Multi-baseline extended particle filtering phase unwrapping algorithm based on amended matrix pencil model and quantized path-following strategy

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Journal of Systems Engineering and Electronics 2019年第1期30卷 78-84页

作者： XIE Xianming ZENG Qingning School of Information and Communication Guilin University of Electronic Technology

This paper proposes a new multi-baseline extended particle filtering phase unwrapping algorithm which combines an extended particle filter with an amended matrix pencil model and a quantized path-following strategy. The contributions to multibaseline synthetic aperture radar(SAR) interferometry are as follows: a new recursive multi-baseline phase unwrapping model based on an extended particle filter is built, and the amended matrix pencil model is used to acquire phase gradient information with a higher precision and lower computational cost, and the quantized path-following strategy is introduced to guide the proposed phase unwrapping procedure to efficiently unwrap wrapped phase image along the paths routed by a phase derivative variance map.

关键词： multi-baseline phase unwrapping interferometric synthetic aperture radar (InSAR) extended particle filter.

Fracture Analysis of Cast Iron Materials with Cracks Based on Elastoplastic extended Finite Element Method

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Acta Mechanica Solida Sinica 2019年第2期32卷 201-214页

作者： Yanjun Chang Qiao Song Zheng Kuang Keshi Zhang Zhanguang Zheng College of Civil Engineering and Architecture Guangxi University Nanning 530004 China College of Mechanical Engineering Guangxi University Nanning 530004 China Guangxi Key Laboratory of Disaster Prevention and Engineering Safety Guangxi University Nanning 530004 China Key Laboratory of Engineering Disaster Prevention and Structural Safety of Ministry of Education Guangxi University Nanning 530004 China

Based on the ABAQUS platform for finite element analysis, the extended finite element method (XFEM) considering elastoplastic constitutive relationship is developed, by which the displacement discontinuity across the crack surface and the strong nonlinearity near the crack tip can be described more accurately. The strip specimens with unilateral cracks and central cracks under uniaxial tension are simulated using the XFEM and the FEM, respectively. The J-integral across the crack on each incremen t is calcula ted using the equivale nt domain integral met hod (EDIM), the interaction integral met hod and the FEM, respectively. The effec ts of mesh size and mesh shape near the crack tip, element type and different calculation methods on the accuracy of J-integral are analyzed. The simulation results show that the XFEM is more accurate than the FEM with the same element size and type. The fracture tests of cast iron specimens with unilateral cracks under uniaxial tension are performed, and the J-integral criterion is valid to predict the fracture initiation in numerical simulation. The critical value of J-integral is calculated using the EDIM of the XFEM. The comparisons demonstrate that the simulated elastoplastic load-displacement curves with the XFEM are in good agreement with the experimental results.

关键词： J-Integral extended finite element Elastoplasticity Fracture criterion

New repairable system model with two types repair based on extended geometric process

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Journal of Systems Engineering and Electronics 2019年第3期30卷 613-623页

作者： WANG Junyuan YE Jimin XIE Pengfei School of Mathematics and Statistics Xidian University

A simple repairable system with one repairman is considered. As the system working age is up to a specified time T, the repairman will repair the component preventively, and it will go back to work as soon as the repair finished. When the system failure, the repairman repair it immediately. The time interval of the preventive repair and the failure correction is described with the extended geometric process. Different from the available replacement policy which is usually based on the failure number or the working age of the system, the bivariate policy (T,N) is considered. The explicit expression of the long-run average cost rate function C(T,N) of the system is derived. Through alternatively minimize the cost rate function C(T,N), the optimal replacement policy (T?,N?) is obtained, and it proves that the optimal policy is unique. Numerical cases illustrate the conclusion, and the sensitivity analysis of the parameters is carried out.

关键词： extended geometric process average cost rate replacement policy renewal reward theorem

Hydro-mechanical modeling of impermeable discontinuity in rock by extended finite element method

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Journal of Central South University 2015年第11期22卷 4337-4346页

作者：郑安兴罗先启 School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University

The extended finite element method(XFEM) is a numerical method for modeling discontinuities within the classical finite element framework. The computation mesh in XFEM is independent of the discontinuities, such that remeshing for moving discontinuities can be overcome. The extended finite element method is presented for hydro-mechanical modeling of impermeable discontinuities in rock. The governing equation of XFEM for hydraulic fracture modeling is derived by the virtual work principle of the fracture problem considering the water pressure on crack surface. The coupling relationship between water pressure gradient on crack surface and fracture opening width is obtained by semi-analytical and semi-numerical method. This method simplifies coupling analysis iteration and improves computational precision. Finally, the efficiency of the proposed method for modeling hydraulic fracture problems is verified by two examples and the advantages of the XFEM for hydraulic fracturing analysis are displayed.

关键词： extended finite element method crack hydraulic fra