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Synthesis and Photocatalytic Activity of One-dimensional ZnO-Zn2SnO4 Mixed Oxide Nanowires

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Chinese Journal of Chemical Physics 2008年第1期21卷 81-86页

作者： Xue-lian Bai Nan Pan xiao-ping wang Hai-qian wang Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technologyof China Hefei 230025 China

Mixed oxide photocatalysts, ZnO-Zn2SnO4 （ZnO-ZTO） nanowires with different sizes were prepared by a simple thermal evaporation method. The ZnO-ZTO nanowires were characterized with a scanning electron microscope, X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive spectrom- eter, and X-ray photoelectron spectra. The photocatalytic activity of the ZnO-ZTO mixed nanowires were studied by observing the photodegradation behaviors of methyl orange aqueous solution. The results suggest that the ZnO-ZTO mixed oxide nanowires have a higher photocatalytic activity than pure ZnO and Zn2SnO4 nanowires. The photocatalyst concentration in the solution distinctly affects the degradation rate, and our results show that higher photodegradation efficiency can be achieved with a smaller amount of ZnO-ZTO nanowire catalyst, as compared to the pure ZnO and ZTO nanowires. Moreover, the photocatalytic activity can also be enhanced by reducing the average diameter of the nanowires. The activity of pure ZnO and ZTO nanowires are also enhanced by physically mixing them. These results can be explained by the synergism between the two semiconductors.

关键词： ZnO Zn2SnO4 Nanowire Photocatalytic activity Photodegradation

Versionized process based on non-volatile random-access memory for fine-grained fault tolerance

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Frontiers of Information Technology & Electronic Engineering 2018年第2期19卷 192-205页

作者： Wen-zhe ZHANG Kai LU xiao-ping wang Science and Technology on Parallel and Distributed Processing Laboratory College of ComputerNational University of Defense Technology

Non-volatile random-access memory（NVRAM） technology is maturing rapidly and its byte-persistence feature allows the design of new and efficient fault tolerance mechanisms. In this paper we propose the versionized process（Ver P）, a new process model based on NVRAM that is natively non-volatile and fault tolerant. We introduce an intermediate software layer that allows us to run a process directly on NVRAM and to put all the process states into NVRAM, and then propose a mechanism to versionize all the process data. Each piece of the process data is given a special version number, which increases with the modification of that piece of data. The version number can effectively help us trace the modification of any data and recover it to a consistent state after a system *** with traditional checkpoint methods, our work can achieve fine-grained fault tolerance at very little cost.

关键词： Non-volatile memory Byte-persistence Versionized process Version number

An Efficient Iterative Method for the Formulation of Flow Networks

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Communications in Computational Physics 2022年第5期31卷 1317-1340页

作者： Wei Hu Dong wang xiao-ping wang Department of Mathematics The Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong School of Science and Engineering The Chinese University of Hong KongShenzhenGuangdong 518172China.

We propose an efficient iterative convolution thresholding method for the formulation of flow networks where thefluid is modeled by the Darcy–Stokesflow with the presence of volume *** method is based on the minimization of the dissipation power in thefluid region with a Darcy *** network is represented by its characteristic function and the energy is approximated under this *** minimization problem can then be approximately solved by alternating:1)solving a Brinkman equation to model the Darcy–Stokesflow and 2)updating the characteristic function by a simple convolution and thresholding *** proposed method is simple and easy to *** prove mathematically that the iterative method has the total energy decaying *** experiments demonstrate the performance and robustness of the proposed method and interesting structures are observed.

关键词： Topology optimization convolution thresholding Darcy-Stokes flow

On extra neutral and charged Higgs bosons at the LHC

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Chinese Science Bulletin 2014年第29期59卷 3729-3737页

作者： xiao-ping wang Shou-Hua Zhu Institute of Theoretical Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Center for High Energy Physics Peking University Collaborative Innovation Center of Quantum Matter

The properties of 125 GeV new particle,which was discovered in 2012 at the Large Hadron Collider(LHC),are found to be consistent with those of the Higgs boson in the standard model(SM).Hereafter the new particle is dubbed as SM-like Higgs *** there is still spacious room for physics beyond the SM(BSM)due to the limited energy and luminosity of the *** more data,experiments will scrutinize whether the new particle is indeed the SM one or *** the same time,one believes that discovery of the SMlike Higgs boson is just the start of the new era of particle *** predominant topic is whether there are other new Higgs bosons as speculated in various BSM *** this short review,we will describe the current status of Higgs physics at the LHC and several BSM models which contain more Higgs *** literatures,there are numerous studies on extended Higgs sector and a comprehensive review is beyond the scope of this ***,we will present two latest studies on Higgs physics:(1)how to detect the charged Higgs boson and measure tan b after including the top polarization information,and(2)how to discover the extra neutral Higgs boson via the pair production of SM-like Higgs boson.

关键词：希格斯玻色子 LHC 中性粒子物理学大型强子对撞机标准模型 BSM 新粒子

Factor analysis on the purity of magnesium titanate directly prepared from seashore titanomagnetite concentrate through direct reduction

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1462-1470页

作者： xiao-ping wang Zhao-chun Li Ti-chang Sun Jue Kou xiao-hui Li School of Mining and Coal Inner Mongolia University of Science and TechnologyBaotou 014010China China Sinda Intellectual Property Limited Beijing 100033China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China

Magnesium titanate was prepared directly through external coal reduction of seashore titanomagnetite concentrate and magnesium oxide(MgO).The effects of roasting temperature and the type and dosage of reductants on the purity of generated magnesium titanate particles were systematically *** electron microscopy and energy-dispersive spectroscopy analyses were performed to characterize the magnesium titanate particles and observe their purity under different *** showed that the roasting temperature remarkably influenced the purity of magnesium *** 1200,1300,and 1400℃,some magnesium ferrite and magnesium aluminate spinel were dissolved in magnesium ***,as the roasting temperature increased to 1500℃,relatively pure magnesium titanate particles were generated because no magnesium ferrite was dissolved in *** type and dosage of the reductants also remarkably affected the purity of magnesium *** amount of fine metallic iron disseminated in the magnesium titanate particles obviously decreased when lignite was used as a reductant at a dosage of 70wt%.Thus,high-purity magnesium titanate particles *** a roasting temperature of 1500℃and with 70wt%lignite,the magnesium titanate product with a yield of 30.63%and an iron content of 3.01wt%was obtained through magnetic separation.

关键词： seashore titanomagnetite magnesium oxide direct reduction magnesium titanate

Effects of Na_2SO_4 on iron and nickel reduction in a high-iron and low-nickel laterite ore

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International Journal of Minerals,Metallurgy and Materials 2018年第4期25卷 383-390页

作者： xiao-ping wang Ti-chang Sun Chao Chen Jue Kou Key Laboratory of Ministry of Education of China for Efficient Mining and Safety of Metal Mines University of Science and Technology Beijing

This study investigates the reactions of Na2SO4 and its effects on iron and nickel reduction in the roasting of a high-iron and low-nickel laterite ore through gas composition, X-ray diffraction, and scanning electron microscope analyses. Results showed that a reduction reaction of Na2SO4 to SO2 was performed with roasting up to 600℃. However, no clear influence on iron and nickel reductions appeared, because only a small amount of Na2SO4 reacted to produce SO2. Na2SO4 reacted completely at 1000℃, mainly producing troilite and nepheline, which remarkably improves selective reduction of nickel. Furthermore, the production of low-melting-point minerals, including troilite and nepheline, accelerated nickel reduction and delayed iron reduction, which is attributed to the concurrent production of magnesium magnetite, whose structure is more stable than the structure of magnetite. Reduction reactions of Na2SO4 resulted in weakening of the reduction atmosphere, and the main product of Na2SO4 changed and delayed the reduction of iron. Eventually, iron metallization was effectively controlled during laterite ore reduction roasting, leading to iron mainly being found in wustite and high iron-containing olivine.

关键词： laterite ore ferronickel reduction magnetic separation

Asymptotic Stability of Periodic Solution for Compressible Viscous van der Waals Fluids

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Acta Mathematicae Applicatae Sinica 2014年第4期30卷 1113-1120页

作者： Jin-yang HUANG xiao-ding SHI xiao-ping wang Bing ZHANG School of Science Beijing University of Chemical Technology Department of Mathematics Hong Kong University of Science and Technology School of Mechanical and Electrical Engineering Beijing University of Chemical Technology

This paper is concerned with the asymptotic stability of the periodic solution to a one-dimensional model system for the compressible viscous van der Waals fluid in Eulerian coordinates. If the initial density and initial momentum are suitably close to the average density and average momentum, then the solution is proved to tend toward a stationary solution as t -→∞.

关键词： van der Waals fluid asymptotic stability global solution

On the Motion of Shear-Thinning Heat-Conducting Incompressible Fluid-Rigid System

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Acta Mathematicae Applicatae Sinica 2018年第3期34卷 534-552页

作者： Ya-zhou CHEN Qiao-lin HE xiao-ding SHI Teng wang xiao-ping wang Faculty of Science Beijing University of Chemical Technology Beijing 100029 China School of Mathematics Sichuan University Sichuan 610065 China College of Applied Sciences Beijing University of Technology Beijing100124 China Department of Mathematics Hong Kong University of Science and Technology H.K. China

The full Navier-Stokes-Fourier system with mixed boundary condition that describes the motion of shear-thinning and incompressible viscous fluid in a rotating multi-screw extruder is investigated. The viscosity is assumed to depend on the shear rate and the temperature. The global existence of suitable weak solutions is established. The fictitious domain method which consists in filling the moving rigid screws with the surrounding fluid and taking into account the boundary conditions on these bodies by introducing a well-chosen distribution of boundary forces is used.

关键词： shear-thinning heat-conducting incompressible fluid suitable weak solution

Molecular Hydrodynamics of the Moving Contact Line in Two-Phase Immiscible Flows

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Communications in Computational Physics 2006年第1期1卷 1-52页

作者： Tiezheng Qian xiao-ping wang ping Sheng Department of Mathematics The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Department of Physics The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina

The no-slip boundary condition,i.e.,zero fluid velocity relative to the solid at the fluid-solid interface,has been very successful in describing many macroscopic flows.A problem of principle arises when the no-slip boundary condition is used to model the hydrodynamics of immiscible-fluid displacement in the vicinity of the moving contact line,where the interface separating two immiscible fluids intersects the solid *** ago it was already known that the moving contact line is incompatible with the no-slip boundary condition,since the latter would imply infinite dissipation due to a non-integrable singularity in the stress near the contact *** this paper we first present an introductory review of the *** then present a detailed review of our recent results on the contact-line motion in immiscible two-phase flow,from molecular dynamics(MD)simulations to continuum hydrodynamics *** extensive MD studies and detailed analysis,we have uncovered the slip boundary condition governing the moving contact line,denoted the generalized Navier boundary *** have used this discovery to formulate a continuum hydrodynamic model whose predictions are in remarkable quantitative agreement with the MD simulation results down to the molecular *** results serve to affirm the validity of the generalized Navier boundary condition,as well as to open up the possibility of continuum hydrodynamic calculations of immiscible flows that are physically meaningful at the molecular level.

关键词： Moving contact line slip boundary condition molecular dynamics continuum hydrodynamics