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Drivability of Large Diameter Steel Cylinders During Hammer-Group Vibratory Installation for the Hong kong–Zhuhai–Macao Bridge

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Engineering 2023年第1期20卷 180-191页

作者： W.j.Lu B.Li j.F.Hou X.W.Xu H.F.Zou L.M.Zhang Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyKowloonHong Kong 999077China The Hong kong University of Science and Technology Shenzhen Research Institute Shenzhen 518057China Tianjin Port Engineering Institute Co. Ltd.of CCCC First Harbor Engineering Co.Ltd.Tianjin 300222China key Laboratory of Port Geotechnical Engineering Ministry of Communications of People’s Republic of ChinaTianjin 300222China CCCC First Harbor Engineering Company Ltd. Tianjin 300461China AECOM Asia Company Limited Hong Kong 999077China

The Hong kong–Zhuhai–Macao Bridge(HZMB)involved the installation of 120 mega-cylinders with a diameter of 22 m,weights up to 513 t,and penetration depths up to 33 m using an eight-vibratory hammer *** to the lack of engineering experience on the drivability of large-diameter cylinders under multiple vibratory hammers,predicting the penetration rate and time of steel cylinders is an open challenge that has a considerable impact on the construction control of the *** this study,the vibratory penetration of large-diameter steel cylinders in the HZMB is investigated based on geological surveys,field monitoring,and drivability *** vibratory penetration rate,installation accuracy,and dynamic responses of the steel cylinders at both the eastern and western artificial islands are *** dynamic soil resistance has a great influence on the cylinder ***,the current design methods for estimating the vibratory driving soil resistance are proven inaccurate without considering the scale ***,a modified method with a normalized effective area ratio A_(r,eff)is proposed in this study to calculate the vibratory soil resistance for open-ended thin-wall cylinders under unplugged *** the scale effects on the vibratory driving soil resistance,the proposed method leads to closer results to the measured data,providing a reference for future engineering practice.

关键词： Hong kong-Zhuhai-Macao Bridge Vibratory pile driving Wave equation analysis Large-diameter steel cylinder Artificial island offshore foundati ons

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The floristic relationship between the upland and lowland Carboniferous wetlands of Variscan Euramerica——Evidence from some medullosalean pteridosperm fronds

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journal of Palaeogeography 2019年第2期8卷 130-141页

作者： Christopher j.Cleal Borja Cascales-Mi?ana Department of Natural Sciences National Museum Wales CNRS University of Lille

Alethopteris grandinii represents remains of fronds of a medullosalean pteridosperm(probably a small tree) that rapidly migrated across the lowland wetland habitats of Variscan Euramerica in middle Asturian(late Moscovian)*** was probably caused by changing drainage patterns within the lowland coal swamps,in response to climate and landscape ***,these medullosaleans had first appeared rather earlier,in early Bolsovian(early Moscovian) times,in upland wetland *** upland habitats may have pre-adapted these plants to the changed condition in the lowland coal swamps.

关键词： Carboniferous Coal swamps Medullosales Upland Migration

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Cadmium sulfide cage photocatalysis coupled electroactive biofilm for synergistic promotion of tetracycline degradation and electricity production

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journal of Materials Science & Technology 2023年第35期166卷 86-97页

作者： Z.S.Yuan j.X.Zou X.L.Zhao j.Y.Shi C.S.Guo M.Yan School of Chemistry and Chemical Engineering Harbin Institute of TechnologyHarbin 150001China

Tetracycline(TC)as a common broad-spectrum antibiotic,has been frequently detected in soil and sur-face *** becomes a great threat to the ecological ***,a device of photocatalysis as-sisted microbial fuel cell(photo-MFC)was constructed for TC degradation and energy *** this photo-MFC,cadmium sulfide(CdS)cage photocatalysis can degrade most of TC in a short *** the Co_(3)O_(4)@C-CC(carbonization and calcination of the ZIF-67 precursor in-situ grown on the carbon cloth(CC))bioanode degrades the rest of TC as well as the photocatalytic products,thus improving the *** co-existence of photocatalysis with bioanode changes the microbial community structure of the *** dominant phylum is Geobacter(60.2%)in normal MFC while that in photo-MFC are Pro-teobacteria(43.5%)and Geobacter(33.2%).Therefore,the synergistic effect of photocatalytic degradation and biodegradation achieves a chemical oxygen demand(COD)removal of 98.6%,which is higher than that of normal MFC(77.6%)or single CdS cage photocatalysis(23.8%).In addition,the photogenerated electrons can be transferred to the cathode,which reduces their combination with holes and increases the electricity generation of MFC,achieving a maximum power density of 3.37 W/m^(2).After degradation,the effluent with 200 mg L^(−1) TC exhibits no visible ***,electrochemical test,finite-difference time-domain(FDTD),density functional theory(DFT)calculation and the free radical trapping experiments verify the possible mechanisms of photocatalytic degradation in this *** strat-egy paves a new way for low energy consumption removal and energy recovery of organic pollutants.

关键词： Photo-MFC CdS cage Tetracycline degradation Mineralization Electricity production

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Recent Progress in Numerical Methods for the Poisson-Boltzmann Equation in Biophysical Applications

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Communications in Computational Physics 2008年第5期3卷 973-1009页

作者： B.Z.Lu Y.C.Zhou M.j.Holst j.A.McCammon Howard Hughes Medical Institute University of CaliforniaSan Diego 9500 Gilman DriveDept.0112La JollaCA 92093-0112USA. Department of Mathematics University of CaliforniaSan Diego 9500 Gilman DriveDept.0112La JollaCA 92093-0112USA. Center for Theoretical Biological Physics University of CaliforniaSan Diego 9500 Gilman DriveDept.0112La JollaCA 92093-0112USA. Department of Chemistry and Biochemistry University of CaliforniaSan Diego 9500 Gilman DriveDept.0112La JollaCA 92093-0112USA. Department of Pharmacology University of CaliforniaSan Diego 9500 Gilman DriveDept.0112La JollaCA 92093-0112USA.

Efficiency and accuracy are two major concerns in numerical solutions of the Poisson-Boltzmann equation for applications in chemistry and *** developments in boundary element methods,interface methods,adaptive methods,finite element methods,and other approaches for the Poisson-Boltzmann equation as well as related mesh generation techniques are *** also discussed the challenging problems and possible future work,in particular,for the aim of biophysical applications.

关键词： Biomolecular electrostatics Poisson-Boltzmann equation numerical methods finite difference methods finite element methods boundary element methods adaptive methods hybrid methods mesh generation electrostatic forces

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Synchronous improvement of mechanical properties and stress corrosion resistance by stress-aging coupled with natural aging pre-treatment in an Al-Zn-Mg alloy with high recrystallization fraction

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journal of Materials Science & Technology 2022年第26期121卷 40-51页

作者： D.Zhang H.C.jiang Z.j.Cui D.S.Yan Y.Y.Song L.j.Rong CAS key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Shandong key Laboratory of Advanced Aluminum Materials and Technology Binzhou 256606China

Enhancing the strength of Al-Zn-Mg alloys is critical to the weight-lightening of structural components in the application of high-speed trains and aerospace industries,while high stress corrosion cracking(SCC)susceptibility of Al-Zn-Mg alloys(especially the alloy with high recrystallization fraction)with high strength makes it *** this study,the influence of tensile stress-aging coupled with natural aging pre-treatment on the mechanical properties and SCC resistance of Al-Zn-Mg alloy with high recrystallization fraction has been *** results show that tensile stress-aging at 160℃can inhibit the dissolution of clusters/Guinier-Preston(GP)zones formed during long-term natural aging pre-treatment,which increases the number density of matrix precipitates(MPts),narrow the width of precipitate free zone(PFZ),and dramatically improve the mechanical properties of the experimental Al-Zn-Mg ***,the precipitation of the high density of MPts within the matrix will assume a large number of solute atoms during artificial aging,which will reduce the supplement of solute atoms to grain *** a result,the volume of anodic active grain boundary precipitates(GBPs)and the content of free solute atoms at grain boundaries are reduced,which reduces the possibility of initial nucleation and propagation of SCC *** coupled treatment method proposed in this study proves efficient in resolving the contradiction between the strength and SCC resistance in Al-Zn-Mg alloy.

关键词： Al-Zn-Mg alloy Natural aging Stress-aging Precipitates Stress corrosion cracking

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Stability of Projection Methods for Incompressible Flows Using High Order Pressure-Velocity Pairs of Same Degree:Continuous and Discontinuous Galerkin Formulations

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Communications in Computational Physics 2014年第8期16卷 817-840页

作者： E.Ferrer D.Moxey R.H.j.Willden S.j.Sherwin ETSIA–School of Aeronautics Universidad Politecnica de MadridPza.Cardenal Cisneros 3MadridE-28040Spain. Department of Aeronautics Imperial College LondonLondonSW72AZUK. Department of Engineering Science University of OxfordParks RoadOxfordOX13PJUK.

This paper presents limits for stability of projection type schemes when using high order pressure-velocity pairs of same *** high order h/p variational methods encompassing continuous and discontinuous Galerkin formulations are used to explain previously observed lower limits on the time step for projection type schemes to be stable[18],when h-or p-refinement strategies are *** addition,the analysis included in this work shows that these stability limits do not depend only on the time step but on the product of the latter and the kinematic viscosity,which is of particular importance in the study of high Reynolds number *** show that high order methods prove advantageous in stabilising the simulations when small time steps and low kinematic viscosities are *** upon this analysis,we demonstrate how the effects of this instability can be reduced in the discontinuous scheme by introducing a stabilisation term into the global ***,we show that these lower limits are compatible with CourantFriedrichs-Lewy(CFL)type restrictions,given that a sufficiently high polynomial order or a mall enough mesh spacing is selected.

关键词： Incompressible Navier-Stokes equations projection methods velocity-correction continuous Galerkin discontinuous Galerkin inf-sup LBB condition.

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Surface Characterisation of Silicon Based MEMS

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Chemical Research in Chinese Universities 2004年第4期20卷 407-410页

作者： LI j. CUI Z M. A. Baker The Surface Analysis Laboratory School of Engineering University of SurreyRutherford Appleton LaboratoryThe Surface Analysis Laboratory School of Engineering University of Surrey Guildford GU2 7XH UKChilton Didcot UKGuildford GU2 7XH UK

Polysilicon Microelectromechanical systems(MEMS) are the subject of intensive researches. Surface chemistry and topography of a MEMS test structure fabricated at Sandia National Laboratory, USA, were studied by means of scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS) and atomic force microscopy(AFM). XPS C_ 1sand Si_ 2pspectra from the polysilicon components, silicon nitride substrate and a reference silicon wafer were compared. The results confirm the presence of a self-assembled monolayer(SAM) on the MEMS surface. An island-like morphology was found on both polysilicon and silicon nitride surfaces of the MEMS. The islands take the form of caps, being up to 0.5 μm in diameter and 20 nm in height. It is concluded that the co-existence of columnar growth and equiaxed growth during the low pressure chemical vapor deposition(LPCVD) of these layers leads to the observed morphology and the islands are caps to the columnar structures.

关键词： Microelectromechanical systems XPS Atomic force microscopy

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Theoretical assessment of the impact of environmental contamination on the dynamical transmission of polio

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International journal of Biomathematics 2019年第2期12卷 1-35页

作者： C.Balde M.Lam A.Bah S.Bowong j.j.Tewa Department of Mathematics Faculty of Science and Technic University Cheikh Anta DiopDakarSenegal Department of Computer Engineering National Advanced School of Engineering University Cheikh Anta Diop DakarSenegal Laboratory of Mathematics Department of Mathematics and Computer Science Faculty of Science University of Douala P.O.Box 24157 DoualaCameroon National Advanced School of Engineering University of Yaounde I P.O.Box 8390 YaoundeCameroon IRD Sorbonne UniversityUHH1SCOF-93143BondyFrance Team GRIMCAPEYaoundeCameroon The African Center of Excellence in Information and Communication Technologies(CETIC)University of Yaounde 1Cameroon

A mathematical model for the dynamical transmission of polio is considered,with the aim of investigating the impact of environment *** model captures two infection pathways through both direct human-to-human transmission and indirect human-to-environment-to-human transmission by incorporating the environment as a transition and/or reservoir of *** derive the basic reproduction number R0^env We show that the disease free equilibrium is globally asymptotically stable(GAS)if R0^env1,there exists a unique endemic equilibrium which is locally asymptotically stable(LAS).Similar results hold for environmental contamination free sub-model(without the incorporation of the indirect transmission).At the endemic level,we show that the number of infected individuals for the model with the environ mental-related contagion is greater than the corresponding number for the environmental contamination free *** conjunction with the inequality R0k to follow rigorously those basic hygienic rules in order to avoid adequate contacts with suspected contaminated ***,we perform numerical simulations to support the theory.

关键词： Poliovirus environment contamination human shedding rate mathematical models stability

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Preliminary Experimental Results of Deep Levels for Dielectronic Recombination in He—Like High—Z Ions at Heidelbreg Electron Beam Ion Trap

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Chinese Physics Letters 2003年第5期20卷 657-659页

作者： ZHANGXue-Mei GUOPan-Lin A.Gonzalez j.CRESPO AppliedIonBeamPhysicsLaboratory InstituteofModernPhysicsFudanUniversityShanghai200433 ShanghaiInstituteofNuclearResearch ChineseAcademyofSciencesShanghai201800 Max-Planck-Institutfurkernphysik Saupfercheckweg1D-69117HeidelbergGermany

An experimental system for dielectronic recombination was set-up on H-EBIT in order to carry out dielectronic recombination study. Some preliminary results of He-like Ge32+ and Cu27+ are obtained. Space charge shift on determination of the resonance position for Ge32+ at 100 mA is around 18% and that for Cu27+ is around 38%. Further analysis of experimental data is in progress.

关键词：实验研究二次电子再结合离子捕获电子束自由电子

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pH-distribution of cerium species in aqueous systems

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journal of Rare Earths 2012年第6期30卷 559-562页

作者： B.Bouchaud j.Balmain *** F.Pedraza University of La Rochelle Laboratory of Engineering Science for the Environment LaSIE FRE-CNRS3474Avenue Michel Crépeau 17042 La Rochelle cedex 01FRANCE

Cerium-based oxide coatings can be obtained through either chemical or electrochemical processes on various conductor and semiconductor substrates. In both cases the films develop through a precipitation mechanism, which strongly depends on the solution chemistry. In the particular case of the electrolytic approach, the elaboration parameters play a key role on the interfacial pH modification thereby leading to an indirect precipitation mechanism. Indeed, the nucleation and growth mechanisms of crystallites and the composition of the resulting layers have been shown to be also strongly affected by the deposition conditions as well as by the substrate composition, which could in turn modify the protectiveness provided by such coatings. Therefore a better fundamental understanding of the system is required, in particular of the distribution of cerium-containing species in aqueous solution. To this end, the present work intended to develop a diagram showing the distribution as well as the relative amount of Ce（Ⅲ）/Ce（Ⅳ） species in aqueous media as a fimction of the pH range. The resulting pH-distribution diagram turned out to be a useful tool to predict the relevant precipitation mechanisms and species involved during the growth of ceriuna-containing films and to draw correlations with the characteristics of the as-deposited films.

关键词： pH-distribution diagram electrodeposition cerium-based oxide films precipitation mechanisms rare earths

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