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Study of Model-free Adaptive Data-driven SMC Algorithm

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International Journal of Automation and computing 2016年第2期13卷 183-190页

作者： wei hu Jie Tang School of Electrical Engineering & Automatic Henan Polytechnic University Yima Coal Group Co. Ltd

A kind of adaptive sliding model control algorithm is developed to solve and improve the mathematical model dependency and un-modeled dynamics of a controlled system. The control strategy derived from a kind of data-driven control method in essence, thereby the input and output data are utilized by the controller with no information about the control system model. Theoretical analysis proves that this proposed control algorithm can improve the utilization of the estimated pseudo partial derivative information and accelerate the velocity of the convergence. The stability of the control system is further verified by rigorous mathematical analysis. This new discrete-time nonlinear systems model-free control algorithm obtained better control performance through the simulations for the linear motor position and the information tracking speed, which also achieved robust and accurate traceability.

关键词： Nonlinear system model-free adaptive control sliding mode control control law pseudo partial derivative

Nonlinear Evolutions of Stimulated Raman and Brillouin Scattering Processes in Partially Stripped-Ion Plasmas

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Chinese Physics Letters 2001年第9期18卷 1230-1233页

作者： hu Ye-Min hu Xi-wei Departmentof Electrical Engineering Huazhong University of Science and TechnologyWuhan 430074 Department of Modern Physics University of Science and Technology of ChinaHefei 230026

Numerical analyses for the nonlinear evolutions of stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) processes are given. Various effects of the second- and third-order nonlinear susceptibilities on the SRS and SBS processes are studied. The nonlinear evolutions of SRS and SBS processes are atfected more efficiently than their linear growth rates by the nonlinear susceptibility.

关键词： Brillouin nonlinear Nonlinear

Artificial Bee Colony Algorithm-based Parameter Estimation of Fractional-order Chaotic System with Time Delay

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IEEE/CAA Journal of Automatica Sinica 2017年第1期4卷 107-113页

作者： Wenjuan Gu Yongguang Yu wei hu School of Economics and Management Beijing Jiaotong University School of Science Beijing Jiaotong University

It is an important issue to estimate parameters of fractional-order chaotic systems in nonlinear science, which has received increasing interest in recent years. In this paper, time delay and fractional order as well as system's parameters are concerned by treating the time delay and fractional order as additional parameters. The parameter estimation is converted into a multi-dimensional optimization problem. A new scheme based on artificial bee colony ABC algorithm is proposed to solve the optimization problem. Numerical experiments are performed on two typical time-delay fractional-order chaotic systems to verify the effectiveness of the proposed method. © 2014 Chinese Association of Automation.

关键词： Chaos theory Chaotic systems Numerical methods Optimization Time delay Timing circuits

Applicability of LIVE/DEAD BacLight stain with glutaraldehyde fixation for the measurement of bacterial abundance and viability in rainwater

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Journal of Environmental Sciences 2017年第1期29卷 202-213页

作者： wei hu Kotaro Murata Daizhou Zhang Faculty of Environmental and Symbiotic Sciences Prefectural University of KumamotoKumamoto 862-8502Japan

Rainwater contains substantial bacteria and rain is an efficient pathway for the dissemination of bacteria from the atmosphere to land and water ***,quantitative information on rainwater bacteria is very limited due to the lack of a reliable *** this study,the epifluorescence microscopy enumeration with the LIVE/DEAD BacLight Bacterial Viability Kit stain was verified to quantify the abundance of viable and non-viable bacterial cells in rainwater,with the 4＇,6-diamidino-2-phenylindole（DAPI） stain for the reference of total cell *** showed that the total counts of bacterial cells by LIVE/DEAD BacLight staining were consistent with those by DAPI staining,and the average detection efficiency was（109 ± 29）%.The ratio of cell count with glutaraldehyde fixation to that without fixation was（106 ± 5）%on *** bacterial concentration in negative control was usually an order of magnitude lower than that in rainwater ***,in case of small precipitation,the abundance in negative control could be more than that in rainwater *** results indicate that the enumeration with LIVE/DEAD BacLight bacterial viability assay coupled with glutaraldehyde fixation and careful negative control investigation is an approach applicable to the measurement of the concentration and viability of bacterial cells in rainwater.

关键词： Bacterial abundance Viability Rainwater LIVE/DEAD BacLight stain Fluorescent enumeration

Accuracy analysis of a single-fault Markov model for FADEC system

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Journal of Systems Engineering and Electronics 2019年第5期30卷 1044-1052页

作者： CAI Jing hu wei CAI Kunye College of Civil Aviation Nanjing University of Aeronautics and Astronautics

Time-limited dispatching(TLD)analysis of the full authority digital engine control(FADEC)systems is an important part of the aircraft system safety analysis and a necessary task for the certification of commercial aircraft and *** the time limited dispatch guidance document ARP5107B,a single-fault Markov model(MM)approach is proposed for TLD ***,ARP5107B also requires that the loss of thrust control(LOTC)rate error calculated by applying the single-fault MM must be less than 5%when performing airworthiness ***,the sources of accuracy errors in three kinds of MM are analyzed and specified through a case study of the general FADEC system,and secondly a two-fault MM considering maintenance policy is established through analyzing and calculating the expected repair time when two related faults ***,a specific FADEC system is given to study on the influence factors of accuracy error in the single-fault MM,and the results show that the accuracy error of the single-fault MM decreases with the increase of short or long prescribed dispatch time,and the range values of short time(ST)and long time(LT)are determined to satisfy the requirement of accuracy error within 5%.

关键词： full authority digital engine control(FADEC)system Markov model(MM) accuracy analysis loss of thrust control(LOTC)

Yield criterions of metal plasticity in different stress states

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Acta Metallurgica Sinica(English Letters) 2009年第2期22卷 123-130页

作者： Fengping YANG Qin SUN wei hu School of Aeronautics Northwestern Polytechnical University Xitan 710072 China Institute of Orthopedic Oncology Tangdu Hospital Fourth Military Medical University Xi＇an 710038 China

Five types of tensile tests were conducted to study the yield .behavior of 2A12-T4 aluminum alloy. Parallel finite element models were built for each test and solved with ABAQUS with different yield criterions. The result shows that any of the four criterions： von Mises yield criterion, Tresca criterion, Twin-Shear criterion and yon Mises criterion with hydrostatic pressure correction, overestimates the yield strengths of the specimens. Rather than hydrostatic pressure, Lode stress parameter is the key factor that affects the differences between experimental and simulation results. Based on this concept, a new yield model with Lode dependence modified from yon Mises criterion is postulated. Although one more parameter needs to be confirmed, the simulation results of this yield model are better than those of other criterions.

关键词： Yield strength Lode stress parameter Hydrostatic pressure Finite element method (FEM)

RATE OF CONVERGENCE OF SCHWARZ ALTERNATING METHOD FOR TIME-DEPENDENT CONVECTION-DIFFUSION PROBLEM

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Journal of Computational Mathematics 2002年第5期20卷 479-490页

作者： Jian-wei hu Cai-hua Wang School of Mathematical Sciences Nankai University300071 Tianjin China Laboratory of Computational Physics IAPCM100088 Beijing China Department of Mathematics Tianjin Normal University300073 Tianjin China

Presents a study that examined the application of an overlapping domain decomposition method to the solution of time-dependent convection-diffusion problems. Background on the Schwartz alternating procedure; Applicati... 详细信息

关键词： rate of convergence Schwarz alternating method convection-diffusion problem

Synthesis and Characterization of Zirconia Nanocrystallites by Cationic Surfactant and Anionic Surfactant

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Chinese Journal of Structural Chemistry 2005年第10期24卷 1133-1139页

作者： YU Jian-Chang hu Sheng-wei College of Material Science and Engineering Fuzhou University Fuzhou 350002 China

Study on nanomaterials has attracted great interests in recent years. In this article, zirconia nanocrystallites of different structures have been successfully synthesized via hydrothermal methods with cationic surfactant （CTAB） and anionic surfactant （SDS）, respectively. Differential Scanning Calorimeter （DSC-TG）, X-ray Diffractometer （XRD）, Transmission Electron Microscope （TEM）, Ultraviolet-Visible （UV-vis） and N2 adsorption-desorption analyses are used for their structure characteristics. The results show that the cationic surfactant has a distinctive direction effect on the formation of zirconia nanocrystallites, while the anionic surfactant has a self-assembly synergistic effect on them. The sample synthesized with the cationic surfactant presents good dispersion with the main phase of tetragonal zirconia, and the average nanocrystal size is around 15 nm after calcination at 500 ℃. While the sample synthesized with the anionic surfactant exhibits a worm-like mesoporous structure with pure tetragonal phase after calcination at 500 ℃ and with good thermal stability.

关键词： cationic surfactant anionic surfactant zirconia nanocrystallites,mesoporous zirconia

Water on silicene： A hydrogen bond-autocatalyzed physisorption-chemisorption-dissociation transition

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Nano Research 2017年第7期10卷 2223-2233页

作者： wei hu Zhenyu Li Jinlong Yang Hefei National Laboratory for Physical Sciences at Microscale Department of Chemical Physics and Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 China Computational Research Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA

A single water molecule is nothing special. However, macroscopic water displays many anomalous properties at interfaces, such as hydrophobicity and hydrophilicity. Although the underlying mechanisms remain elusive, hydrogen bonds between water molecules are expected to play a major role in these interesting phenomena. An important question concerns whether water clusters containing few molecules are qualitatively different from a single molecule. Using the water adsorption behavior as an example and by carefully choosing two-dimensional silicene as the substrate material, we demonstrate that water monomers, dimers, and trimers show distinct adsorption properties at the substrate surface. On silicene, the additional water molecules in dimers and trimers induce a transition from physisorption to chemisorption and then to dissociation, arising from the enhancement of charge transfer and proton transfer processes induced by hydrogen bonding. Such a hydrogen bond autocatalytic effect is expected to have broad applications in metal-free catalysis for the oxygen reduction reaction and water dissociation.

关键词： hydrogen bond silicene physisorption chemisorption dissociation density functional theory