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Ref.ned asymptotics for minimal graphs in the hyperbolic space

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Science China Mathematics 2019年第2期62卷 381-390页

作者： weiming Shen Yue Wang Beijing International Center for Mathematical Research Peking University School of Mathematical Sciences Peking University

We study the boundary behaviors of solutions f to the Dirichlet problem for minimal graphs in the hyperbolic space with singular asymptotic boundaries and characterize the boundary behaviors of f at the points strictly located in the tangent cones at the singular points on the boundary. for n =2, we also obtain a ref.ned estimate of f.

关键词： asymptotic behaviors minimal graphs singular domains

Crystal structures and hydrogenation behavior of (Ca_(0.9)Sr_(0.1))_8(Al_(1-x)Zn_x)_3 alloys

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Rare Metals 2008年第2期27卷 134-137页

作者： SI Tingzhi YAnG weiming ZHAnG Qing＇an School of Materials Science and Engineering Anhui University of Technology Maanshan 243002 China

The crystal structures and hydrogenation behavior of the （Ca0.9Sr0.1）8（Al1-xZnx）3 （x = 0, 0.1, 0.2, 0.3 and 0.4） alloys were investigated. The new phase （Ca,Sr）E（Al,Zn） was found whenx 〉 0.1. （Ca, Sr）E（Al,Zn） crystallizes in space group 14/mmm （A-139）. The lattice parameters were calculated to be a = b = 1.1616（2） nm, c = 1.6422（4） nm. Zn atoms occupy the 8h and 16n sites together with Al atoms. The （Ca0.9Sr0.1）8Al3 alloy only contains a single Ca8Al3 phase. The （Ca0.9Sr0.1）8（Al1-xZnx）3 alloys consist of Ca8Al3, CasZn3, Ca and （Ca,Sr）2（Al,Zn） phases when x is from 0.1 to 0.3. As x increasing to 0.4, the alloy consists of （Ca,Sr）E（Al,Zn）, Ca8Zn3 and Ca. The hydrogenated （Ca0.9Sr0.1）8Al3 and （Ca0.9Sr0.1）8（Al0.9Zn0.1）3 samples consist of CartE and Al. The （Ca0.9Sr0.1）8（Al1-xZnx）3 （x = 0.2, 0.3 and 0.4） samples can be hydrogenated into CaH2, Al and CaZnl3 under a hydrogen pressure of 5 MPa at 473 K.

关键词： calcium-based alloys crystal structure X-ray diffraction hydrogenation behavior.

A Multi-Layer Collaboration framework for Industrial Parks with 5G Vehicle-to-Everything networks

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Engineering 2021年第6期7卷 818-831页

作者： Yanjun Shi Qiaomei Han weiming Shen Xianbin Wang Department of Mechanical Engineering Dalian University of TechnologyDalian 116024China Department of Electrical and Computer Engineering Western UniversityLondonON N6A 3K7Canada State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

The fifth-generation(5G)wireless communication networks are expected to play an essential role in the transformation of vertical *** many exciting applications to be enabled by 5G,logistics tasks in industry parks can be performed more efficiently via vehicle-to-everything(V2X)*** this paper,a multi-layer collaboration framework enabled by V2X is proposed for logistics management in industrial *** proposed framework includes three layers:a perception and execution layer,a logistics layer,and a configuration *** addition to the collaboration among these three layers,this study addresses the collaboration among devices,edge servers,and cloud *** effective logistics in industrial parks,task collaboration is achieved through four f.nctions:environmental perception and map construction,task allocation,path planning,and vehicle *** dynamically coordinate these f.nctions,device–edge–cloud collaboration,which is supported by 5G slices and V2X communication technology,is ***,the analytical target cascading method is adopted to configure and evaluate the collaboration schemes of industrial ***,a logistics analytical case study in industrial parks is employed to demonstrate the feasibility of the proposed collaboration framework.

关键词： 5G Vehicle-to-everything Industrial park Logistics Device–edge–cloud collaboration Analytical target cascading

Highly stable and antifouling graphene oxide membranes prepared by bio-inspired modification for water purification

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Chinese Chemical Letters 2020年第10期31卷 2651-2656页

作者： weiming Zhong Yuyu Zhang Ling Zhao Wanbin Li Guangdong Key Laboratory of Environmental Pollution and Health School of EnvironmentJinan UniversityGuangzhou 511443China

Graphene oxide(GO)membranes show great potential in molecular separation for water ***,the inferior stability of GO membranes is a major bottleneck for practical *** this study,bio-inspired polydopamine(PDA)deposition is reported for enhancing the stability of GO *** simple and mild immersion,PDA is self-polymerized on GO *** blocking of PDA chains to membrane defects improves the rejections for various *** the inherently strong adhesion and crosslinking of PDA greatly strengthen the interactions of substrates to GO layers and the binding force of GO nanosheets,the prepared PDA-GO membranes exhibit impressive long-te rm stability in cross-flow filtration,and maintain good nanofiltration perfo rmance at various feed pressures,tangential velocities,and eve n after external ***,because the deposited PDA layers obstruct the direct contact between GO and contaminants,the antifouling property of the PDA-GO membranes increases substantially,with recovery ratio about 98%.

关键词： Graphene oxide nanofiltration Polydopamine Stability Antifouling

numerical simulation of solitary and random wave propagation through vegetation based on VOf method

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Acta Oceanologica Sinica 2013年第7期32卷 38-46页

作者： ZHAnG Mingliang HAO Zining ZHAnG Yunpeng WU weiming School of Ocean and Environment Engineering Dalian Ocean University national Center for Computational Hydroscience and Engineering University of MississippiUniversity

A vertical two-dimensional numerical model has been applied to solving the Reynolds Averaged navier- Stokes （RAnS} equations in the simulation of current and wave propagation through vegetated and non- vegetated waters. The k-e model is used for turbulence closure of RAnS equations. The effect of vegeta- tion is simulated by adding the drag force of vegetation in the flow momentum equations and turbulence model. To solve the modified n-S equations, the f.nite difference method is used with the staggered grid system to solver equations. The Youngs＇ fractional volume of fluid （VOf） is applied tracking the free sur- face with second-order accuracy. The model has been tested by simulating dam break wave, pure current with vegetation, solitary wave runup on vegetated and non-vegetated channel, regular and random waves over a vegetated field. The model reasonably well reproduces these experimental observations, the model- ing approach presented herein should be useful in simulating nearshore processes in coastal domains with vegetation effects.

关键词： VOf method vegetation solitary regular and random waves wave height attenuation k-emodel

nondestructive estimation of bok choy nitrogen status with an active canopy sensor in comparison to a chlorophyll meter

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Pedosphere 2020年第6期30卷 769-777页

作者： Rongting JI weiming SHI Yuan WAnG Hailin ZHAnG Ju MIn State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China Department of Plant and Soil Sciences Oklahoma State UniversityStillwater OK 74078-6028USA

Precise estimation of vegetable nitrogen(n)status is critical in optimizing n fertilization ***,nondestructive and accurate n diagnostic methods for vegetables are relatively *** our two-year field experiment,we evaluated whether an active canopy sensor(GreenSeeker)could be used to nondestructively predict n status of bok choy(Brassica rapa ***)compared with a chlorophyll *** showed that the normalized difference vegetation index(nDVI)and ratio vegetation index(RVI)generated by the active canopy sensor were well correlated with the aboveground biomass(AGB)(r=0.698–0.967),plant n uptake(PnU)(r=0.642–0.951),and root to shoot ratio(RTS)(r=-0.426 to-0.845).Compared with the chlorophyll meter,the active canopy sensor displayed much higher accuracy(5.0%–177.4%higher)in predicting AGB and PnU and equal or slightly worse(0.54–1.82 times that of the chlorophyll meter)for *** sensor-based nDVI model performed equally well in estimating AGB(R2=0.63)and PnU(R2=0.61),but the meter-based model predicted RTS better(R2=0.50).Inclusion of the days after transplanting(DAT)significantly improved the accuracy of sensor-based AGB(19.0%–56.7%higher)and PnU(24.6%–84.6%higher)estimation *** f.ndings suggest that the active canopy sensor has a great potential for nondestructively estimating n status of bok choy accurately and thus for better n recommendations,especially with inclusion of DAT,and could be applied to more vegetables with some verification.

关键词： aboveground biomass GreenSeeker model prediction n diagnosis normalized difference vegetation index plant n uptake root to shoot ratio ratio vegetation index soil and plant analyer development(SPAD)

Promoting Effect of ZnO on the Catalytic Performance of CoZSM-5 for CO_(2)-Assisted Dehydrogenation of Ethane

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Chemical Research in Chinese Universities 2023年第6期39卷 1064-1069页

作者： HE Huan ZOU Zhengxi HUA weiming YUE Yinghong GAO Zi Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Department of ChemistryFudan UniversityShanghai 200433P.R.China

Aseries of ZnO-modified cobaltous ion exchanged ZSM-5 catalysts is prepared using incipient wetness impregnation and characterized by X-ray diffraction(XRD),n2 adsorption,transmission electron microscopy(TEM),UV-Vis diffuse reflectance spectroscopy(DR UV-Vis),X-ray photoelectron spectroscopy(XPS),pyridine-adsorbed fourier transform infrared(Py-IR)and *** catalytic performance towards CO_(2)-assisted dehydrogenation of ethane to ethylene has been *** addition of ZnO onto CoZSM-5 obviously improved the yield of ethylene as well as the conversion of CO_(2).The promoting effect is attributed to the good activity of ZnO for the reverse water gas shift(RWGS)reaction,which enhances the coupling between RWGS and ethane dehydrogenation.

关键词： Ethane dehydrogenation CO_(2)utilization ZnO CoZSM-5 Coupling

Dynamic evolution of.nitrogen and oxygen dual-coordinated single atomic copper catalyst during partial oxidation of benzene to phenol

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nano Research 2022年第4期15卷 3017-3025页

作者： weiming Chen Hongqiang Jin f.ng He Peixin Cui Changyan Cao Weiguo Song Beijing national Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular SciencesLaboratory of Molecular Nanostructures and NanotechnologyInstitute of ChemistryChinese Academy of SciencesBeijing 100190China Beijing national Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular SciencesLaboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Single atom catalysts(SACs)with metal_(1)-n_(x)sites have shown promising activity and selectivity in direct catalytic oxidation of benzene to *** reaction pathway is considered to be involving two steps,including a H_(2)O_(2)molecule dissociated on the metal single site to form the(metal_(1)-n_(x))=O active site,and followed by the dissociation of another H_(2)O_(2)on the other side of metal atom to form O=(metal_(1)-n_(x))=O intermediate center,which is active for the adsorption of benzene molecule via the formation of a C-O bond to form *** this manuscript,we report a Cu SAC with nitrogen and oxygen dual-coordination(Cu1-n3O1 moiety)that doesn’t need the first H_(2)O_(2)activation process,as verified by both experimental and density f.nction theory(DfT)calculations *** with the counterpart nitrogen-coordinated Cu SAC(denoted as Cu1/nC),Cu SAC with nitrogen and oxygen dual-coordination(denoted as Cu1/nOC)exhibits 2.5 times higher turnover frequency(TOf)and 1.6 times higher utilization efficiency of H_(2)O_(2).Particularly,the coordination number(Cn)of Cu atom in Cu1/nOC maintains four even after H_(2)O_(2)treatment and *** DfT calculations,the dynamic evolution of single atomic Cu with nitrogen and oxygen dualcoordination in hydroxylation of benzene is *** f.ndings provide an efficient route to improve the catalytic performance through regulating the coordination environments of SACs and demonstrate a new reaction mechanism in hydroxylation of benzene to phenol reaction.

关键词： single atom catalyst coordination dynamic evolution benzene oxidation phenol

Enhanced debromination of 4-bromophenol by the UV/sulfite process：Efficiency and mechanism

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Journal of Environmental Sciences 2017年第4期29卷 231-238页

作者： Bihuang Xie Xuchun Li Xianf.ng Huang Zhe Xu weiming Zhang Bingcai Pan State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing University

Halogenated aromatic compounds have attracted increasing concerns due to their toxicity and persistency in the environment, and dehalogenation is one of the promising treatment and detoxification methods. Herein, we systematically studied the debromination efficiency and mechanism of para-bromophenol（4-BP） by a recently developed UV/sulfite process. 4-BP underwent rapid degradation with the kinetics accelerated with the increasing sulfite concentration, pH（6.1–10） and temperature, whereas inhibited by dissolved oxygen and organic solvents. The apparent activation energy was estimated to be 27.8 kJ/mol. The degradation mechanism and pathways of 4-BP were explored by employing n2O and nitrate as the electron scavengers and liquid chromatography/mass spectrometry to identify the intermediates. 4-BP degradation proceeded via at least two pathways including direct photolysis and hydrated electron-induced debromination. The contributions of both pathways were distinguished by quantifying the quantum yields of 4-BP via direct photolysis and hydrated electron production in the system. 4-BP could be readily completely debrominated with all the substituted Br released as Br-, and the degradation pathways were also proposed. This study would shed new light on the efficient dehalogenation of brominated aromatics by using the UV/sulfite process.

关键词： Debromination Brominated aromatics UV/sulfite process Hydrated electron Mechanism