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UV–visible spectral characterization and density functional theory simulation analysis on laser-induced crystallization of amorphous silicon thin films

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Chinese Physics B 2014年第3期23卷 293-297页

作者：黄璐金晶史伟民袁志军杨伟光曹泽淳王林军周军楼祺洪 School of Material Science and Engineering Shanghai University Shanghai institute of Optics and Fine Mechanics Chinese Academy of SciencesNovel Laser Technique and Application System Laboratory

The effect of laser energy density on the crystallization of hydrogenated intrinsic amorphous silicon （a-Si：H） thin films was studied both theoretically and experimentally. The thin films were irritated by a frequency-doubled （λ= 532 nm） Nd：YAG pulsed nanosecond laser. An effective density functional theory model was built to reveal the variation of bandgap energy influenced by thermal stress after laser irradiation. Experimental results establish correlation between the thermal stress and the shift of transverse optical peak in Raman spectroscopy and suggest that the relatively greater shift of the transverse optical （TO） peak can produce higher stress. The highest crystalline fraction （84.5%） is obtained in the optimized laser energy density （1000 mJ/cm2） with a considerable stress release. The absorption edge energy measured by the UV- visible spectra is in fairly good agreement with the bandgap energy in the density functional theory （DFT） simulation.

关键词： laser crystallization UV-visible spectra density functional theory simulation

UCT Based Search in Phantom Go

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UCT Based Search in Phantom Go

Aerodynamic configuration integration design of hypersonic cruise aircraft with inward-turning inlets

第25届中国控制与决策会议

作者： Shiquan Shen Jie Xu Hongye Li Tan Zbu Jiao Wang Dalian Measuring and Control technique Research institute College of Information Science and Engineering Northeastern University

ISBN: (纸本)9781467355339

Phantom Go is a kind of imperfect information two-player *** combines the large searching space in Go and the uncertainty of imperfect information games. Monte Carlo methods and UCT algorithm were suggested applying in Phantom Go and got certain *** applying Monte Carlo methods in Phantom Go,guessing opponent stones is the first step. In this paper, we discussed some special situations in Phantom Go to infer some of opponent’s stones based on the current information and gave a method for guessing opponent *** we applied UCT search using previous simulation results in Phantom Go and compared it with Monte Carlo Tree Search.

关键词： Phantom Go Imperfect Information Games UCT Monte-Carlo Tree Search

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Chinese Journal of Aeronautics 2017年第4期30卷 1349-1362页

作者： Jifei WANG Jinsheng CAI Chuanzhen LIU Yanhui DUAN Yaojie YU School of Aeronautics Northwestern Polytechnical University Aerodynamics theory and Application institute China Academy of Aerospace Aerodynamics Computational Aerodynamics institute China Aerodynamics Research and Development Center

In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the help of this method, the major design concern of balancing the aerodynamic performance against the requirements for efficient propulsion can be well addressed. A novel geometric parametrically modelling method based on a combination of patched class and shape transition（CST） and COONs surface is proposed to represent the configuration, especially a complex configuration with an irregular inlet lip shape. The modelling method enlarges the design space of components on the premise of guaranteeing the configuration integrity via special constraints imposed on the interface across adjacent surfaces. A basic flow inside a cone shaped by a dual-inflection-point generatrix is optimized to generate the inward-turning inlet with improvements of both compression efficiency and flow uniformity. The performance improvement mechanism of this basic flow is the compression velocity variation induced by the variation of the generatrix slope along the flow path. At the design point, numerical simulation results show that the lift-to-drag ratio of the configuration is as high as 5.2 and the inlet works well with a high level of compression efficiency and flow uniformity. The design result also has a good performance on off-design conditions. The achievement of all the design targets turns out that the integration design method proposed in this paper is efficient and practical.

关键词： Aerodynamic configurations Hypersonic Integration design Inward-turning inlet Numerical simulation

Distributed robust MPC for nonholonomic robots with obstacle and collision avoidance

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Control theory and Technology 2022年第1期20卷 32-45页

作者： Li Dai Yanye Hao Huahui Xie Zhongqi Sun Yuanqing Xia School of Automation Beijing Institute of TechnologyBeijing100081China Xi’an Aeronautics Computing technique Research institute AVICXi’an710065ShaanxiChina Yangtze Delta Region Academy of Beijing institute of Technology Jiaxing314019China

Considering that the inevitable disturbances and coupled constraints pose an ongoing challenge to distributed control algorithms,this paper proposes a distributed robust model predictive control(MPC)algorithm for a multi-agent system with additive external disturbances and obstacle and collision avoidance *** particular,all the agents are allowed to solve optimization problems simultaneously at each time step to obtain their control inputs,and the obstacle and collision avoidance are accomplished in the context of full-dimensional controlled objects and *** achieve the collision avoidance between agents in the distributed framework,an assumed state trajectory is introduced for each agent which is transmitted to its neighbors to construct the polyhedral over-approximations of *** the polyhedral over-approximations of the agent and the obstacles are used to smoothly reformulate the original nonconvex obstacle and collision avoidance *** a compatibility constraint is designed to restrict the deviation between the predicted and assumed ***,recursive feasibility of each local MPC optimization problem with all these constraints derived and input-to-state stability of the closed-loop system can be ensured through a sufficient condition on controller ***,simulations with four agents and two obstacles demonstrate the efficiency of the proposed algorithm.

关键词： Distributed model predictive control Robust control Multi-agent system Obstacle and collision avoidance Convex optimization

A New Species of the Genus Tylototriton(Amphibia: Urodela: Salamandridae) from the Southern Dabie Mountains in Anhui Province

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Asian Herpetological Research 2017年第3期18卷 151-164页

作者： Lifu QIAN Xiaonan SUN Jiaqi LI Weibo GUO Tao PAN Xing KANG Hui WANG Jianping JIANG Jun WU Baowei ZHANG Anhui Key Laboratory of Eco-engineering and Bio-technique School of Life SciencesAnhui University Nanjing institute of Environmental Sciences under the Ministry of Environmental Protection Chengdu institute of Biology Chinese Academy of Sciences

A new species of the genus Tylototriton is described,from Yuexi county,Anhui province,in the south of the Dabie *** is based on morphological and molecular *** new species is identified as belonging to the Tylototriton asperrimus group and shares a number of similarities with ***,*** and *** diagnostic characteristics of the new species are as follows： the head length is greater than the width of the head; bony ridges on the head are prominent and necked-in; the distal digit ends,ventral digits,peripheral area of the cloaca and the tail＇s lower edge are *** result from the molecular analysis of the genus Tylototriton（including the type specimen of the new species） based on three mitochondrial genes（ND1,ND2 and CYTB） indicated that the new species was close to ***,***,and ***,but formed an independent *** result was consistent with the morphological analysis above,which supports the theory that the population distributed in the south of the Dabie Mountains,namely in from Yuexi county,Anhui province,represented a distinct species,Tylototriton anhuiensis ***.

关键词： new species Tylototriton anhuiensis sp. nov. southem Dabie Mountains taxonomy morphology molecular analyses

Burning rate analysis of laser controlled 5-aminotetrazole propellant

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Defence Technology（防务技术） 2023年第4期22卷 10-27页

作者： Nianbai He Ruiqi Shen Luigi T.DeLuca Lizhi Wu Wei Zhang Yinghua Ye School of Chemical Engineering Nanjing University of Science and Technology210094JiangsuChina institute of Space propulsion Nanjing University of Science and Technology210094JiangsuChina Space propulsion Laboratory(Ret) Department of Aerospace Science and TechnologyPolitecnico di Milano20156MilanItaly

As an innovative propulsion technique, laser augmented chemical propulsion(LACP) seems superior to the traditional ones. However, the corresponding combustion theories have still to be ascertained for LACP. Burning rate of 5-aminotetrazole(5-ATZ) propellant has been studied by testing pressed samples under different combustor pressures and laser powers. Based on micro computed tomography(Micro CT),an advanced thickness-over-time(TOT) method to characterize the regression of the produced nonplanar burning surface is established. Because of a shell structure covering the combustion surface,the burning rate of the implemented 5-ATZ propellant is not constant during laser ablation. Resorting to functional fitting, a new law of non-constant burning including the effect of the observed unique burning surface structures is proposed. Accordingly, applicable combustion conditions of 5-ATZ based propellants have been preliminarily speculated for future research activities.

关键词： 5-Aminotetrazole(5-ATZ) Laser-augmented chemical propulsion(LACP) Non-constant burning rate Micro computed tomography(MicroCT) Non-planar burning surface

Cooperative guidance law based on super-twisting observer for target maneuvering

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Journal of Systems Engineering and Electronics 2024年第5期35卷 1304-1314页

作者： GAO Mengjing YAN Tian HAN Bingjie CHENG Haoyu FU Wenxing HAN Bo Unmanned System Research institute Northwestern Polytechnical UniversityXi’an 710072China AVIC Xi’an Aeronautics Computing technique Research institute Xi’an 710072China 93525 Troops Shigatse 857000China

To solve the problem that multiple missiles should simultaneously attack unmeasurable maneuvering targets,a guidance law with temporal consistency constraint based on the super-twisting observer is ***,the relative motion equations between multiple missiles and targets are established,and the topological model among multiple agents is ***,based on the temporal consistency constraint,a cooperative guidance law for simultaneous arrival with finite-time convergence is ***,the unknown target maneuver-ing is regarded as bounded *** on the second-order sliding mode theory,a super-twisting sliding mode observer is devised to observe and track the bounded interfer-ence,and the stability of the observer is *** with the existing research,this approach only needs to obtain the sliding mode variable which simplifies the design *** simulation results show that the designed cooperative guidance law for maneuvering targets achieves the expected *** ensures successful cooperative attacks,even when confronted with strong maneuvering targets.

关键词： cooperative guidance super-twisting target maneuver finite time convergence.

An incremental elastic-plastic cohesive constitutive model with considering damage

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Science China(Technological Sciences) 2023年第12期66卷 3651-3662页

作者： XIA Tong QIAN YiXing XU ShengYao YANG ZhenYu LU ZiXing institute of Solid Mechanics School of Aeronautic Science and EngineeringBeihang University(BUAA)Beijing 100083China Aircraft&propulsion Laboratory Ningbo Institute of Technology(NIT)Beihang University(BUAA)Ningbo 315832China

The interface has a significant influence on the macroscopic mechanical behaviors of composite materials,with interface cracking being a typical failure *** ability to precisely describe the mechanical behavior of the interface is critical for analyzing the failure of composite *** on plasticity theory and damage mechanics,an elastic-plastic interface constitutive model is developed to simulate the irreversible plastic deformation at the interface under the cyclic loading ***,by incorporating a damage factor in scalar form,the model is able to simulate mixed loading forms(Modes I and II).The influence of interfacial strength and toughness on the overall mechanical properties of unidirectional fiber reinforced composites under transverse loading is studied with this *** simulation results are consistent with the experimental data in the literature,demonstrating the model's *** model can be used to simulate the mechanical behavior of composites with interfaces under cyclic loading,and it is helpful for understanding the plastic behavior and damage accumulation at the interfaces in the composites.

关键词： interface cohesive zone model plasticity damage fiber reinforced composites

Active Control of Thermo-mechanical Buckling of Composite Laminated Plates Using Piezoelectric Actuators

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Acta Mechanica Solida Sinica 2021年第3期34卷 369-380页

作者： Yao Zhang Yu Xue Wei Yuan Wensheng Ma Jinqiang Li Fengming Li College of Aerospace and Civil Engineering Harbin Engineering UniversityHarbin 150001China Key Laboratory of Aero-engine Vibration technique AECC Hunan Aviation Power Plant Research InstituteZhuzhou12000China

This paper is concerned with the active control of thermomechanical buckling of composite laminated plates using piezoelectric facesheets as *** four-variable trigonometric shear deformation theory and Hamilto's principle are applied to formulate the governing equation of structural *** temperature feedback control strategy is proposed to conduct the active control of thermal-mechanical *** simulation results show that the thermo-mechanical buckling of composite laminated plates can be effectively controlled by the presented control *** a specific control gain,the critical mechanical buckling load can remain constant at different *** effects of geometric parameters,fiber angle,stacking sequence,position of piezoelectric layer and boundary conditions on the active control of thermo-mechanical buckling are also investigated.

关键词： Buckling control Thermo-mechanical buckling Laminated plate Piezoelectric actuator Temperature feedback