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Dynamics of a prey-predator system under Poisson white noise excitation

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Acta Mechanica Sinica 2014年第5期30卷 739-745页

作者： Shan-Shan Pan wei-qiu Zhu Department of Mechanics State Key Lab of Fluid Power Transmission and ControlZhejiang University

The classical Lotka-Volterra （LV） model is a well-known mathematical model for prey-predator ecosystems. In the present paper, the pulse-type version of stochastic LV model, in which the effect of a random natural environment has been modeled as Poisson white noise, is in- vestigated by using the stochastic averaging method. The averaged generalized It6 stochastic differential equation and Fokkerlanck-Kolmogorov （FPK） equation are derived for prey-predator ecosystem driven by Poisson white noise. Approximate stationary solution for the averaged generalized FPK equation is obtained by using the perturbation method. The effect of prey self-competition parameter e2s on ecosystem behavior is evaluated. The analytical result is confirmed by corresponding Monte Carlo （MC） simulation.

关键词： Prey-predator ecosystem Poisson white noise Stochastic averaging- Approximate stationary solution. Per turbation method

Decomposition of Organic Compounds in Coke Plant Wastewater by Ultrasonic Irradiation and Its Combined Process

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Chemical Research in Chinese Universities 2004年第4期20卷 421-428页

作者： XUJin-qiu JIAJin-ping WANGJing-wei SchoolofEnvironmentalScienceandEngineering ShanghaiJiaotongUniversityShanghai200240P.R.China DepartmentofEnvironmentalEngineering ShanghaiSecondPoly-technicUniversityShanghai201206P.R.China

The paper deals with the degradation of the organic compounds in the coke plant wastewater by the combined process of ultrasonic irradiation and activated sludge. The influence factors of the ultrasonic degradation effect such as air atmosphere, initial concentration, ultrasonic power density and the category and consumption of catalyst were investigated. A water quality model was used to explain the degradation of different kinds of organic compounds in the coke plant wastewater by ultrasonic irradiation. After the wastewater was treated by the combined process of ultrasonic irradiation and activated sludge, the COD degradation efficiency was 95.74%, which is 63.49% higher than that by the process of activated sludge alone.

关键词： Coke plant wastewater Organic compounds Ultrasonic irradiation Activated sludge Degradation Water quality model

Study on Commercial Application of FCC with Auxiliary Gasoline Reactor for Improving FCC Naphtha Quality

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China Petroleum Processing & Petrochemical Technology 2007年第3期9卷 17-21页

作者： wei qiang PetroChina Harbin Petrochemical Company Harbin 150056

This article introduces the commercial application of FCC technology equipped with a gasoline auxiliary reactor in the RFCC unit at PetroChina Harbin Petrochemical Branch Company. Test results have shown the excellent outcome for commercial application of the gasoline upgrading in the auxiliary reactor to reduce the olefin content in FCC naphtha. Application of this technology can reduce the olefin content in FCC naphtha to less than 35 v%. Adjustment of the FCC operation towards more severe conditions can further reduce the olefin content in FCC naphtha to less than 20 v%, so that the FCC naphtha can meet the current standard or meet more stringent specification requirements in the future to achieve compelling economic and social benefits.

关键词： catalytic cracking gasoline olefin commercial application

Desilication kinetics of calcined boron mud in molten sodium hydroxide media

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Journal of Central South University 2016年第9期23卷 2191-2198页

作者： NING Zhi-qiang SONG qiu-shi ZHAI Yu-chun XIE Hong-wei YU Kai School of Materials and Metallurgy Northeastern University Shenyang 110004 China

Desilication kinetics of calcined boron mud(CBM) occurring in molten sodium hydroxide media was investigated. The effects of factors such as reaction temperature and Na OH-to-CBM mass ratio on silicon extraction efficiency were studied. The results show that silicon extraction efficiency increases with increasing the reaction time and Na OH-to-CBM mass ratio. There are two stages for the desilication process of the calcined boron mud. The overall desilication process follows the shrinking-core model, and the first and second stages of the process were determined to obey the shrinking-core model for surface chemical reaction and the diffusion through the product layer, respectively. The activation energies of the first and second stages were calculated to be 44.78 k J/mol and 15.94 k J/mol, respectively.

关键词： boron mud sodium hydroxide silicon dioxide kinetics desilication

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

Phase thermal stability and mechanical properties analyses of(Cr,Fe,V)–(Ta,W)multiple-based elemental system using a compositional gradient film

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International Journal of Minerals,Metallurgy and Materials 2020年第10期27卷 1379-1387页

作者： qiu-wei Xing Jiang Ma Yong Zhang Beijing Advanced Innovation Center of Materials Genome Engineering State Key Laboratory of Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronics Engineering College of Mechatronics and Control EngineeringShenzhen UniversityShenzhen 518060China

High-entropy alloys(HEAs)generally possess complex component combinations and abnormal *** traditional methods of investigating these alloys are becoming increasingly inefficient because of the unpredictable phase transformation and the combination of many *** development of compositionally complex materials such as HEAs requires high-throughput experimental methods,which involves preparing many samples in a short *** we apply the high-throughput method to investigate the phase evolution and mechanical properties of novel HEA film with the compositional gradient of(Cr,Fe,V)-(Ta,W).First,we deposited the compositional gradient film by ***,the mechanical properties and thermal stability of the(Cr0.33Fe0.33V0.33)x(Ta0.5W0.5)100−x(x=13-82)multiplebased-elemental(MBE)alloys were *** the deposited wafer was annealed at 600℃for 0.5 h,the initial amorphous phase was transformed into a body-centered cubic(bcc)structure phase when x=*** were observed on the film surface when x was 72 and ***,the highest hardness of as-deposited films was found when x=18,and the maximum hardness of annealed films was found when x=33.

关键词： high-throughput fabrication hard coating thermal resistance mechanical property phase stability high-entropy alloys

Protecting lithium metal anode in all-solid-state batteries with a composite electrolyte

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Rare Metals 2021年第2期40卷 409-416页

作者： Wen-Qing wei Bing-qiang Liu Yi-qiang Gan Hai-Jian Ma Da-wei Cui School of Mechanical-electronic and Vehicle Engineering Weifang UniversityWeifang261061China Department of Chemical and Materials Engineering the University of AucklandAuckland1142New Zealand College of Mechanical and Electronic Engineering Shandong University of Science and TechnologyQingdao266590China

The volume of the metallic lithium anode in allsolid-state Li metal batteries increases significantly due to the lithium dendrite formation during the battery cycling,and the rough surface of lithium metal also reduces Li-ion transport in Li/electrolyte *** this work,we developed a solid polymer composite by adding the lowcost Si_(3)N_(4)particles to protect the lithium anode in allsolid-state *** Fourier transform infrared spectroscopy(FTIR)data show that the surface of 10 wt%Si_(3)N_(4)particles interacts with the polyethylene oxide(PEO)and lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)salt;the interaction restricts the anion mobility and improves the ionic conductivity(1×10^(-4)S·cm^(-1))and lithium-ion transference number(0.28)of the composite *** lithium metal anode is well protected by the composite electrolyte in all-solid-state cells,including symmetric and Li/LiFePO_(4)*** lithium dendrite growth suppression by this composite electrolyte indicates the possible application of these low-cost composite electrolytes for lithium metal protection.

关键词： Lithium metal anode Lithium dendrite growth Composite electrolyte Symmetric cell

Simulating coupled dynamics of a rigid-flexible multibody system and compressible fluid

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Science China(Physics,Mechanics & Astronomy) 2018年第4期61卷 54-68页

作者： wei Hu qiang Tian HaiYan Hu Ministry of Education Key Laboratory of Dynamics and Control of Flight Vehicle School of Aerospace Engineering Beijing Institute of Technology

As a subsequent work of previous studies of authors, a new parallel computation approach is proposed to simulate the coupled dynamics of a rigid-flexible multibody system and compressible fluid. In this approach, the smoothed particle hydrodynamics(SPH) method is used to model the compressible fluid, the natural coordinate formulation(NCF) and absolute nodal coordinate formulation(ANCF) are used to model the rigid and flexible bodies, respectively. In order to model the compressible fluid properly and efficiently via SPH method, three measures are taken as follows. The first is to use the Riemann solver to cope with the fluid compressibility, the second is to define virtual particles of SPH to model the dynamic interaction between the fluid and the multibody system, and the third is to impose the boundary conditions of periodical inflow and outflow to reduce the number of SPH particles involved in the computation process. Afterwards, a parallel computation strategy is proposed based on the graphics processing unit(GPU) to detect the neighboring SPH particles and to solve the dynamic equations of SPH particles in order to improve the computation efficiency. Meanwhile, the generalized-alpha algorithm is used to solve the dynamic equations of the multibody system. Finally, four case studies are given to validate the proposed parallel computation approach.

关键词： smoothed particle hydrodynamics(SPH) compressible flow Riemann solver absolute nodal coordinate formulation(ANCF) graphics processing unit(GPU)

A Kernel PCA Shape Prior and Edge Based MRF Image Segmentation

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Chinese Journal of Electronics 2016年第5期25卷 892-900页

作者： WANG Xili ZHANG wei JI qiang School of Computer Science Shaanxi Normal University Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute

We introduce both shape prior and edge information to Markov random field(MRF) to segment target of interest in images. Kernel Principal component analysis(PCA) is performed on a set of training shapes to obtain statistical shape representation. Edges are extracted directly from images. Both of them are added to the MRF energy function and the integrated energy function is minimized by graph cuts. An alignment procedure is presented to deal with variations between the target object and shape templates. Edge information makes the influence of inaccurate shape alignment not too severe, and brings result smoother. The experiments indicate that shape and edge play important roles for complete and robust foreground segmentation.

关键词： Kernel Principal component analysis(PCA) Shape prior Edge Markov random field(MRF) Image segmentation