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Theoretical Modelling.of Metallurg.cal Defect Closing.Up Processes During.Forming.a Forg.ng

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Journal of Iron and Steel Research International 2013年第9期20卷 111-116页

作者： g.Banaszek S Berski H Dyja A Kawaek Czestochowa University of Technolog.

Computer modelling.using.an FEM-based prog.am, i.e. Forg. 2008, was carried out. Laboratory model-ling.of the process of free hot forg.ng.in shaped anvils was conducted to close up metallurg.cal defects. Results ob- tained from the simulation modelling.were processed by using.a commercial statistical packag., i.e. Statistica 6.0 PL. The influence of the anvil shape and main parameters of the forg.ng.process on closing.up metallurg.cal defects were determined. On the basis of the investig.tion carried out, the optimal values of main forg.ng.technolog.eal parameters and suitable g.oups of anvils to be used in particular forg.ng.tag.s are proposed for the elimination of metallurg.cal defects.

关键词： shape anvil metallurg.cal defect free forg.ng objective function FEM

Introducing.a New Tool for Studying.Unstable Systems

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International Journal of Automation and computing 2014年第6期11卷 580-587页

作者： Frantiek g.zdo Tomas Bata University in Zlín Faculty of Applied Informatics nam.T.G.Masaryka 5555760 01 Zlin Czech Republic

This paper presents the starting.project of a web site focussed on unstable systems. It is a web-based database in a biling.al version(Eng.ish/Czech), which can be used as an information database for models of unstable processes. The web site contains the mathematical models of such systems, including.their simulation files tog.ther with basic information about the stability of dynamic systems. The paper outlines the motivation for the development of this database, presents its basic structure, and discusses several models from the site. The areas of prospective usag. are also sug.ested tog.ther with the possible directions of further development of this project. The contribution ends with a case study using.the database for control system analysis and desig. of the Amira inverted pendulum. The systematic polynomial approach is fruitfully utilised for the task tog.ther with some useful tools from the robust control theory.

关键词： Unstable systems stability modelling simulation database robust control polynomial approach

Calibration and uniqueness analysis of microparameters for DEM cohesive g.anular material

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International Journal of Mining.Science and Technolog. 2022年第1期32卷 121-136页

作者： Song.ao Ji Jurij Karlovšek School of Civil Eng.neering The University of QueenslandBrisbane 4067Australia

The differential evolution(DE)alg.rithm was deployed to calibrate microparameters of the DEM cohesive g.anular material.4 macroparameters,namely,uniaxial compressive streng.h,direct tensile streng.h,Young.s modulus and Poisson’s ratio,can be calibrated to hig. *** best calibration accuracy could reach the sum of relative errors RE_(sum)g.h and normal-to-shear stiffness ratio control the elastic behaviour and stable crack g.owth,(2)microparameters cohesion and friction ang.es present a neg.tive linear correlation that controls the axial strain and lateral strain prior to the peak stress,and(3)microparameters friction coefficient controls shear crack friction and slip mainly refers to the unstable crack *** of more macroparameters to reg.late the material mechanical behaviour that is dominated by shear crack and slip motion is hig.lig.ted for future *** DE calibration method is expected to serve as an alternative method to calibrate the DEM cohesive g.anular material to its peak streng.h.

关键词： Discrete element method(DEM) Particle flow code(PFC) Differential evolution(DE) Parameter calibration Uniqueness analysis Post-peak behaviour

Stochastic many-body calculations of moiréstates in twisted bilayer g.aphene at hig. pressures

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npj Computational Materials 2022年第1期8卷 89-98页

作者： Mariya Romanova Vojtěch Vlček Department of Chemistry and Biochemistry University of CaliforniaSanta BarbaraCA93106-9510USA

We introduce three developments within the stochastic many-body perturbation theory:efficient evaluation of off-diag.nal self-energ. terms,construction of Dyson orbitals,and stochastic constrained random phase *** stochastic approaches readily handle systems with thousands of *** use them to explore the electronic states of twisted bilayer g.aphene(tBLg.characterized by g.ant unit cells and correlated electronic *** document the formation of electron localization under compression;weakly correlated states are merely shifted in *** demonstrate how to efficiently downfold the correlated subspace on a model Hamiltonian with a screened frequency-dependent two-body *** the 6°tBLg.system,the onsite interactions are between 200 and 300 meV under *** Dyson orbitals exhibit spatial distribution similar to the mean-field sing.e-particle *** pressure,the electron-electron interactions increase in the localized states;however,the dynamical screening.does not fully balance the dominant bare Coulomb interaction.

关键词： interaction twisted stochastic

Characteristics of Underg.ound Water Flow at Different Water Levels in Tiansheng.n Karst Area, Yunnan, China

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Acta g.olog.ca Sinica(Eng.ish Edition) 2010年第1期84卷 206-212页

作者： Janja KOg.Vek Karst Research Institute ZRC SAZU Titov trg 2 SI-6230 Postojna Slovenija

Three tracing.tests from the same injection point executed at low, medium, and hig. water levels in the karst aquifer near Tiansheng.n villag., Lunan Stone Forest, Yunnan Province, China, have revealed the basic properties of underg.ound water flow. They showed the g.neral directions of water flows; tracer concentrations were observed at six successive points allowing.for the calculation of apparent dominant flow velocities at these sections towards the Dalong.an karst spring. For the hig. water level, the discharg. between sing.e sections was between two and 10 times g.eater than that at low water level. For the medium water level, the flow velocity at different sections was between 1.4 and 3.7 times faster than that at low water level; and for hig. water level, it was between 1.3 and 2.7 times faster than that at medium water level. The fastest water flow appeared at the first section （23 cm/s at medium water level）; and the slowest （0.6 cm/s at low water level） appeared where water flow must cross the Tiansheng.n fault （north-south direction）, and later, a layer of 20-30 m thickness of quartz sandstone and shale clay-stones. It was also possible to calculate the recovery of the tracer for point 4, Dakenyan, where discharg. was measured. At the medium water level, 50% of the injected tracer was detected a half-day after its first appearance and at low water level after more than 3 days. The previously published research illustrates the transport velocities of possible contaminants and their solubilities in water at different hydrolog.cal conditions.

关键词： karst tracing.test underg.ound water flow Lunan Yunnan China

Electrochemical studies of Meldola blue-modified bilayer lipid membranes

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Chinese Science Bulletin 1997年第3期42卷 203-207页

作者： Ding. L Wang. ek CHINESE ACAD SCI CHANGCHUN INST APPL CHEMELECTROANALYT CHEM LABCHANGCHUN 130022PEOPLES R CHINA

BILAYER lipid membranes (BLM) have been extensively reg.rded as a basic structure that forms the matrix of biolog.cal membranes. The properties of BLM may be altered by incorporation and modification and can be employed to study many membrane processes. Especially biosensors and bi-molecular electronic devices made by BLM have a wide application. Many kinds of org.nic dyes are known as biolog.cal stains and often used in biolog., physiolog., pharmacolog. and medicine. In g.neral, coloring.and staining.processes involve adsorp-

关键词： Meldola blue bilayer lipid membranes (BLM) electrochemistry.

STM imag. of tung.tosilicic acid molecular layer on hig.ly oriented pyrolytic g.aphite

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Chinese Journal of Chemistry 1995年第6期13卷 493-496页

作者： Zhang. BL Wang. ek CHINESE ACAD SCI CHANGCHUN INST APPL CHEMELECTROANALYT CHEM LABCHANGCHUN 130022JILINPEOPLES R CHINA

Molecular layer of tung.tosilicic acid (H4SiW12O40) deposited on freshly-cleaved hig.ly oriented pyrolytic g.aphite (HOPg. was observed by scanning.tunneling.microscopy (STM) in air at room temperature. The molecular dimension (11.5 Ang.trom) of H4SiW12O40 measured by STM is consistent with known crystallog.aphic parameter. We also imag.d the boundary of H4SiW12O40 molecular layer on HOPg.showing.that molecular layer of H4SiW12O40 was formed. It has been proved that individual tung.tosilicic acid species is imag.d. The probable reason for the formation of the molecular layer is also discussed.

关键词： tung.tosilicic acid HOPg STM

Analytical study of subcritical crack g.owth under mode I loading.to estimate the roof durability in underg.ound excavation

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International Journal of Mining.Science and Technolog. 2022年第2期32卷 375-385页

作者： Song.ao Ji Zeng.Wang.Jurij Karlovšek g.otechnical Eng.neering.Centre School of Civil EngineeringThe University of QueenslandBrisbane 4067Australia China Coal Technolog.&Eng.neering.g.oup Nanjing.Desig.&Research Institute Co. Ltd.Nanjing 210031China

The long.term stability of the roof is particularly important in desig.ing.underg.ound rock *** estimate the durability of roof strata in underg.ound excavation,a computation scheme of subcritical crack g.owth is proposed in this *** adopting.the proposed method,the potential collapse location of strata is derivable in accordance with a static model,the durability of roof strata can be estimated,a dynamic time step control strateg. is achieved to balance the accuracy and speed of computing.and the initial crack size of rock can be *** addition to the above,a mechanical model of underg.ound excavation with non-uniformly distributed loads and partially yielded foundation is presented as the prototypical case.A set of case studies is carried out that showcase a power correlation between applied stress and roof *** allowable applied tensile stress for a 100-year life cycle is about 76%of the tensile *** using.the proposed subcritical crack g.owth computation scheme,the roof stability in an underg.ound excavation can be identified not only from the spatial view but also from the temporal perspective.

关键词： Roof durability Analytical model Subcritical crack g.owth Stress intensity factor Initial crack size Dynamic time step

Dislocation Vibration, Morse Potential Function and Temperature Dependence of Critical Resolved Shear Stress of Some Sing.e Crystals

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Journal of Materials Science & Technolog. 1999年第4期15卷 311-314页

作者： Wang. JY Tan, ek Lu, CW Chinese Acad Sci Met Res Inst Int Ctr Mat Phys Shenyang 110015 Peoples R China

By using.Morse potential model, we calculate the temperature dependence of critical resolved shear stress (CRSS) of some sing.e crystals. Dislocation-phonon interaction is considered in this paper. Theoretical calculations fit experimental law well. Investig.tions show: interatomic force is the physical intrinsic that controls the plastic deformation processing.of materials, and the temperature dependence of CRSS mainly comes from the temperature dependence of dislocation vibration.

关键词： Sing.e crystals