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An efficient method for collision-free and jerk-constrained trajectory generation with sparse desired way-points for a flying robot

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Science China(Technological Sciences) 2021年第8期64卷 1719-1731页

作者： CHEN YongXue dong wei DING Ye State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai200240China

In this paper,an efficient approach is developed to plan jerk-constrained smooth trajectories passing through desired way-points with allowable accuracy for an autonomous ***,based on the B-spline model,we introduce the sequential convex programming(SCP)into the flexible path planning method to satisfy the way-points *** approximating the quadrotor and obstacles as spheres and directed planes,the length-optimal and collision-free path planning problem is formulated as a nonconvex optimization problem and solved by *** initial C^(3) continuous path curve for optimization is constructed efficiently based on a proposed strategy of generating new way-points near the obstacles without the need to calculate the embedding distance between the curve and the *** this basis,the time-optimal speed planning problem is addressed in two *** the first step,the forward-backward approach is introduced to solve the problem under the chord error,velocity,and acceleration constraints by changing the variables and deforming the *** by relaxing the constraints appropriately,the problem under jerk constraints is formulated into a linear programming(LP)*** feasibility of the proposed approach is verified through simulations and an indoor navigation *** proposed approach can generate a C^(3) continuous collision-free trajectory that passes through the sparse desired way-points with allowable accuracy while guaranteeing the chord error,velocity,acceleration,and jerk *** the number of sample points is 3000,the proposed speed planning method reduces the calculation time by 40%compared to an existing method.

关键词： collision avoidance speed optimization motion planning sequential convex programming quadrotor

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Observer-based Multirate Feedback Control Design for Two-time-scale System

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International Journal of Automation and computing 2021年第6期18卷 1007-1016页

作者： Ravindra Munje wei-dong Zhang Department of Electrical Engineering K.K.Wagh Institute of Engineering Education and ResearchNashik 422003India Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China

The use of a lower sampling rate for designing a discrete-time state feedback-based controller fails to capture information of fast states in a two-time-scale system, while the use of a higher sampling rate increases the amount of computation considerably. Thus,the use of single-rate sampling for systems with slow and fast states has evident limitations. In this paper, multirate state feedback(MRSF) control for a linear time-invariant two-time-scale system is proposed. Here, multirate sampling refers to the sampling of slow and fast states at different sampling rates. Firstly, a block-triangular form of the original continuous two-time-scale system is constructed. Then, it is discretized with a smaller sampling period and feedback control is designed for the fast subsystem. Later, the system is block-diagonalized and equivalently represented into a system with a higher sampling period. Subsequently, feedback control is designed for the slow subsystem and overall MRSF control is derived. It is proved that the derived MRSF control stabilizes the full-order system. Being the transformed states of the original system, slow and fast states need to be estimated for the MRSF control ***, a sequential two-stage observer is formulated to estimate these states. Finally, the applicability of the design method is demonstrated with a numerical example and simulation results are compared with the single-rate sampling method. It is found that the proposed MRSF control and observer designs reduce computations without compromising closed-loop performance.

关键词： Feedback control multirate sampling sequential observer two-stage design two-time-scale system

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Recent Advances in Pd-Catalyzed Reactions Involving the “On-Water” Mechanism

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Chinese Journal of Chemistry 2024年第5期42卷 533-542页

作者： dong wei Guo-Qiang Lin State Key Laboratory of Systems Medicine for Cancer Shanghai Cancer InstituteShanghai Key Laboratory of Systems Regulation and Clinical Translation for CancerRen Ji HospitalShanghai Jiao Tong University School of MedicineShanghai200127 China State Key Laboratory of Chemical Biology Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200032 China

As the chemical industry grapples with the need for more eco-friendly practices,the use of water as a reaction medium is gaining attraction in organic *** mini-review delves into Pd-catalyzed reactions that utilize the "on-water" mechanism,spanning from 2019 to late *** reactions are neatly categorized into several types: (A) Catalytic C—H activations,(B) Mizoroki- Heck-type reactions,(C) Suzuki-Miyaura reactions,and (D) Cyclization *** showcasing the potential of water as a sustainable reaction medium for organic transformations,these reactions leave no doubt about the importance of embracing eco-friendly practices in the chemical *** Scientists In 1980,a seminal work by Breslow et *** an acceleration of reaction rate in the Diels-Alder *** and co-workers noted a significant increase in the rate of the [2σ+2σ+2π] cycloaddition of quadricyclane and dimethyl azodicarboxylate (DMAD) when the reaction was conducted in water,as opposed to when it was carried out in organic *** term "on-water" was then coined to describe this *** strategy was further expanded to transition-metal catalyzed transformations by Ackermann in ***,Varma and Leazer disclosed a Pd-catalyzed Mizoroki-Heck type arylation of alkenes with diaryliodonium salts “on-water”.The enantioselective version of "on-water" process was not realized until 2014 by the Zhou *** on,the Schaub group described a Pd-catalyzed Suzuki–Miyaura coupling reaction of electron-poor aryl chlorides with water,using only 50 ppm of catalyst *** recently,Liu and Lin extended the "on-water" strategy to Pd-catalyzed double Mizoroki-Heck *** mini-review has focused on Pd-catalyzed reactions involving the “on-water” mechanism.

关键词： Pd-catalyzed “On-water” Green chemistry Aqueous reactions Mechanism Methodology and reactions Mizoroki-Heck reaction Cross-coupling

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Probabilistic synthesis against GR(1) winning condition

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Frontiers of Computer Science 2022年第2期16卷 17-25页

作者： wei ZHAO Rui LI Wanwei LIU wei dong Zhiming LIU College of Computer Science&Technology Nanjing University of Aeronautics and AstronauticsNanjing 211106China College of Computer&Information Science Southwest UniversityChongqing 400715China School of Computer National University of Defense TechnologyChangsha 410073China

Reactive synthesis is a technique for automatic generation of a reactive system from a high level *** system is reactive in the sense that it reacts to the inputs from the *** specification is in general given as a linear temporal logic(LTL)*** behaviour of the system interacting with the environment can be represented as a game in which the system plays against the ***,a problem of reactive synthesis is commonly treated as solving such a game with the specification as the winning *** synthesis has been thoroughly investigated for more two decades.A well-known challenge is to deal with the complex uncertainty of the *** understand that a major issue is due to the lack of a sufficient treatment of probabilistic properties in the traditional *** example,a two-player game defined by a standard Kriple structure does not consider probabilistic transitions in reaction to the uncertain physical environment;and a Markov Decision Process(MDP)in general does not explicitly separate the system from its environment and it does not describe the interaction between system and the *** this paper,we propose a new and more general model which combines the two-player game and the ***,we study probabilistic reactive synthesis for the games of General Reactivity of Rank 1(i.e.,GR(1))defined in this *** specifically,we present an algorithm,which for given model,a location and a GR(1)specification,determines the strategy for each player how to maximize/minimize the probabilities of the satisfaction of at *** use an example to describe the model of probabilistic games and demonstrate our algorithm.

关键词： reactive system probabilistic synthesis GR(1)

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Existence and Multiplicity Results for a Degenerate Elliptic Equation

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Acta Mathematica Sinica,English Series 2006年第3期22卷 665-670页

作者： wei dong Jian Tao CHEN Hebei University of Engineering

The goal of this paper is to study the multiplicity result of positive solutions of a class of degenerate elliptic equations. On the basis of the mountain pass theorems and the sub- and supersolutions argument for p-Laplacian operators, under suitable conditions on the nonlinearity f（x, s）, we show the following problem：-△pu=λu^α-a（x）u^q in Ω,u│δΩ=0 possesses at least two positive solutions for large λ, where Ω is a bounded open subset of R^N, N ≥ 2, with C^2 boundary, λ is a positive parameter, Ap is the p-Laplacian operator with p 〉 1, α, q are given constants such that p - 1 〈α 〈 q, and a（x） is a continuous positive function in Ω^-.

关键词： degenerate elliptic equation mountain pass theorem maximal positive solution

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Functionalization of C,C-palladacycles:application in the synthesis of functional molecules

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Science China Chemistry 2023年第10期66卷 2721-2733页

作者： dong wei Guo-Qiang Lin State Key Laboratory of Systems Medicine for Cancer Shanghai Cancer InstituteRen Ji HospitalShanghai Jiao Tong University School of MedicineShanghai 200127China Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Significant advancements have been achieved in the field of C,C-palladacycles functionalization in recent decades,which have greatly contributed to the synthesis of intricate drug molecules,natural products,innovative materials,and chiral ***,these advancements have led to the establishment of highly efficient and atom-economic synthetic *** on the differences in the C–Pd bonds,C,C-palladacycles can be further classified into several main types:C(aryl),C(alkyl)-,C(aryl),C(aryl)-,C(aryl),C(vinyl)-,and C(alkyl),C(carbonyl)-*** minireview will highlight the recent advances in the synthesis of functional molecules through the functionalization of different C,C-palladacycles,and we hope this survey will inspire future strategic developments for C,C-palladacycle catalysts and their synthetic application.

关键词： C,C-palladacycles functionalization synthetic application

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Optimality conditions and duality for a class of nondifferentiable multiobjective generalized fractional programming problems

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Applied Mathematics(A Journal of Chinese Universities) 2008年第3期23卷 331-344页

作者： GAO Ying RONG wei-dong School of Mathematical Sciences Inner Mongolia University Hohhot 010021 China

This paper studies a class of multiobjective generalized fractional programming problems, where the numerators of objective functions are the sum of differentiable function and convex function, while the denominators are the difference of differentiable function and convex function. Under the assumption of Calmness Constraint Qualification the Kuhn-Tucker type necessary conditions for efficient solution are given, and the Kuhn-Tucker type sufficient conditions for efficient solution are presented under the assumptions of （F, α, ρ, d）-V-convexity. Subsequently, the optimality conditions for two kinds of duality models are formulated and duality theorems are proved.

关键词： operations research multiobjective generalized fractional programming optimality condition duality theorem generalized convexity

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Forging-microstructure-tensile properties correlation in a new nearβhigh-strength titanium alloy

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Rare Metals 2021年第8期40卷 2109-2117页

作者： Huan Wang She-wei Xin Yong-Qing Zhao wei Zhou wei-dong Zeng State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Titanium Alloy Research Institute Northwest Institute for Nonferrous Metal ResearchXi’an710016China

Microstructures and tensile properties of a newβhigh-strength titanium alloy Ti-5321(Ti-5 Al-3 Mo-3 V-2 Zr-2 Cr-1 Nb-1 Fe)were investigated in this *** microstructures,including equiaxed microstructure(EM),bimodal microstructure(BM),basket-weave microstructure(WM)and lamellar microstructure(LM),were tailored by changing the forging process,and the influences of different microstructures on tensile properties were also *** results indicated that Ti-5321 exhibits a better combination of strength and ductility,compared to Ti-5553,Ti-1023,BT22 and *** ultimate tensile strength,total elongation and reduction in area could be achieved in a range of 1200-1300 MPa,10%-15%and40%-60%,*** influences of variant selection on the tensile properties in Ti-5321 alloy were also ***βforging and solution treatment,αphase maintained strictly Burgers orientation relation with adjacentβ*** features of the fractography in BM and LM were also explored to further explain the tensile properties and the fracture mode of Ti-5321 alloy.

关键词： New nearβtitanium alloy Forging process Variant selection Tensile properties

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Hydrothermal Synthesis and Crystal Structure of a Novel Polymolybdic(VI) Acid: {[H_3O]_2^+[Mo_2O_4(OH)_6]^(2-)}_n

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Chinese Journal of Structural Chemistry 2006年第6期25卷 653-656页

作者： WANG wei-dong HU Mao-Lin Hubei Key Laboratory of Bioanalytical Technique Hubei Normal University Huangshi Hubei 435002 China Department of Chemistry and Environmental Engineering Hubei Normal University Huangshi Hubei 435002China School of Chemistry and Materials Science Wenzhou University Wenzhou Zhejiang 325027 China

A novel supramolecular polymolybdic（VI） acid was unexpectedly synthesized by the reaction of sodium molybdate with 1,2,4,5-benzenetetracarboxylic and trichloroacetic acids in 1：1：1 molar ratio under hydrothermal condition. The crystal belongs to tetragonal with space group P4/mbm, a = 0.88867（17）, b = 0.88867（17）, c = 0.55676（15） nm, Z = 3, V = 0.43969（17） nm^3, Dc = 4.486 g/cm^3,μ = 4.365 mm^-1, F（000） = 576, R = 0.0273 and wR = 0.0679. In the crystal, the Mo（VI） atoms are six- and five-coordinated in distorted octahedral and trigonal bipyramidal geometries, respectively. Furthermore, these Mo（VI） atoms, bearing different coordinated environments, are bridged by OH groups with disorder O atoms to form a twodimensional framework with pentagonal grids. It is worthy of notice that these adjacent twodimensional frameworks are extended into a three-dimensional supramolecular array with pentagonal large cavities＇by Van Der Waals＇ forces and hydrogen bonding interactions.

关键词： polymolybdic acid hydrothermal synthesis crystal structure two-dimensional framework

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Synthesis and Crystal Structure of Tetraaquacopper(II) Bis(5-fluorouracil-1-acetate) Tetrahydrate

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Chinese Journal of Structural Chemistry 2006年第5期25卷 562-566页

作者： WANG wei-dong HU Mao-Lin Hubei Key Laboratory of Bioanalytical Technique Hubei Normal University Huangshi Hubei 435002 China Department of Chemistry and Environmental Engineering Hubei Normal University Huangshi Hubei 435002 China School of Chemistry and Materials Science Wenzhou University Wenzhou 325027 China

The title compound, [Cu（C6H4N2O4F）2（H2O）4].4（H2O） I, has been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction method. It crystallizes in monoclinic, space group P21/c with a = 8.3041（17）, b = 12.045（2）, c = 11.077（2） A, β = 92.567（3）°, V= 1106.8（4） A^3, Mr = 581.89, Z= 2, Dc = 1.746 g/cm^3, F（000） = 598,μ（MoKa） = 1.090 mm^-1, the final R = 0.0296 and wR = 0.0806 for 3195 observed reflections with Ⅰ 〉 2σ（Ⅰ）. In the centrosymmetric compound I, each Cu（Ⅱ） ion is coordinated by six O atoms from two 5-fluorouracil-1-acetate anions and four water molecules, forming a six-coordinated octahedral environment. N-H…O and O-H…O hydrogen-bonding interactions are observed in the structure, leading to the formation of a three-dimensional network.

关键词： copper crystal structure 5-fluorouracil-1-acetate

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