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Volumetric changes in the focal areas of seismic events corresponding to destress blasting

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International journal of Mining Science and Technology 2019年第4期29卷 541-547页

作者： P.Konicek j.Schreiber l.Nazarova Department of Geomechanics and Mining Research Institute of Geonics of the Czech Academy of SciencesOstrava 70800Czech Republic laboratory of Mining Informatics Chinakal Institute of Mining of the Siberian Branch of the Russian Academy of ScienceNovosibirsk 630091Russia

The typical development of total volumetric change in the focal areas of seismic events,corresponding to destress blasting,is characterized as an explosive phase followed by an implosive phase and with alternating additional phases following on from *** a few cases,a non-typical development of volumetric change was identified,where the first phase was implosive and the second phase,*** development is mainly typical for induced seismic events recorded during mining,not for destress *** events were recorded during longwall mining in the Czech part of the Upper Silesian Coal Basin,where the destress blasting technique is used as a rockburst prevention active *** source processes in the focal areas of selected seismic events were analyzed by the seismic moment tensor inversion method,as well as by studying geomechanical rock mass conditions at the localities of the seismic *** main goal of the analysis was to attempt to identify the reasons for non-typical development of volumetric changes in these *** changes were analyzed for seismic events with energy greater than 104 j,recorded in the period of time from 1993 to 2009(1109 events).80%(891)of the recorded seismic events were induced seismic events that were registered during longwall mining and 20%(218)corresponded to destress blasting *** shows that the main reason for the non-typical development of volumetric changes in the focal areas of seismic events is an association with destress blasting in the rock mass,which is very close to rock mass *** detonation of explosives in boreholes,which would dominate the first phase of volumetric changes,probably obscured stress release in the rock mass,as manifested in the first implosion phase of the volumetric changes in this case.

关键词： Destress blasting Seismic event Volumetric changes Stress release

A semi-analytical approach for calculating the equilibrium structure and radial breathing mode frequency of single-walled carbon nanotubes

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Acta Mechanica Sinica 2016年第6期32卷 1075-1087页

作者： j.Gong l.Thompson G.li Department of Mechanical Engineering Clemson University

A semi-analytical model for determining the equilibrium configuration and the radial breathing mode (RBM) frequency of single-wall carbon nanotubes (CNTs) is presented. By taking advantage of the symmetry characteristics, a CNT structure is represented by five independent variables. A line search optimization procedure is employed to determine the equilibrium values of these variables by minimizing the potential energy. With the equilibrium configuration obtained, the semi-analytical model enables an efficient calculation of the RBM frequency of the CNTs. The radius and radial breathing mode frequency results obtained from the semi-analytical approach are compared with those from molecular dynamics (MD) and ab initio calculations. The results demonstrate that the semi-analytical approach offers an efficient and accurate way to determine the equilibrium structure and radial breathing mode frequency of CNTs.

关键词： Carbon nanotubes Equilibrium structure Radial breathing mode frequency

High-magnetic-field induced charge order in high-T_c cuprate superconductors

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Chinese Physics B 2019年第11期28卷 25-42页

作者： l X Zheng j.l. T WU Hefei National laboratory for Physical Science at Microscale University of Science and Technology of ChinaHefei 230026China Key laboratory of Strongly-coupled Quantum Matter Physics University of Science and Technology of ChinaChinese Academy of SciencesHefei 230026China CAS Center for Excellence in Superconducting Electronics(CENSE) Shanghai 200050China CAS Center for Excellence in Quantum Information and Quantum Physics Hefei 230026China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

In the last few years, charge order and its entanglement with superconductivity are under hot debate in high-Tc community due to the new progress on charge order in high-Tc cuprate superconductors YBa2Cu3O6+x. Here, we will briefly introduce the experimental status of this field and mainly focus on the experimental progress of high-field nuclear magnetic resonance(NMR) study on charge order in YBa2Cu3O6+x. The pioneering high-field NMR work in YBa2Cu3O6+x sets a new stage for studying charge order which has become a ubiquitous phenomenon in high-Tc cuprate superconductors.

关键词： charge order cuprates nuclear magnetic resonance YBa2Cu3O6+x superconductors competing order

Microstructural Development and Deformation Mechanisms during Cold Rolling of a Medium Stacking Fault Energy TWIP Steel

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journal of Materials Science & Technology 2013年第2期29卷 161-167页

作者： K.A. Ofei l. Zhao j. Sietsma Materials Innovation Institute M2i Mekelweg 2 2628 CD Delft The Netherlands Department of Materials Science and Engineering Delft University of Technology Mekelweg 2 2628 CD Delft The Netherlands

The magnetic response, microstructural and texture changes occurring during cold rolling of a Fe-14Mn-0.64C-2.4AI-0.25Si medium stacking fault energy TWlP （twinning induced plasticity） steel have been studied by X-ray diffraction and magnetic techniques. The changes in the sub-grain size （Ds）, probability of stacking fault formation （Psf） and microstrain in the material as cold rolling progressed were determined by using a modified version of the Williamson and Hall equation. A strong development of the crystallographic texture with increasing deformation was observed. Deformation-induced formation of a small fraction α＇-martensite was observed, indicating that the steel also exhibits γ→α＇-martensite transformation during cold rolling, which is discussed via the changes of the stacking-fault probability and the texture development during cold rolling.

关键词： TWIP steel α'-Martensite Sub-grain size Probability of stacking fault formation Texture development

GUIDED WAVES IN MUlTIlAYERED PlATES: AN IMPROVED ORTHOGONAl POlYNOMIAl APPROACH

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Acta Mechanica Solida Sinica 2014年第5期27卷 542-550页

作者： jiangong Yu j.E.lefebvre l.Elmaimouni School of Mechanical and Power Engineering Henan Polytechnic University Department of Civil Engineering University of Siegen Univ lille Nord de France F-59000 Lille France UVHC IEMN-DOAE F-59313 Valenciennes Cedex 9 France CNRS UMR 8520 F-59650 Villeneuve d’Ascq France ERSITA Faculte Polydisciplinaire d’Ouarzazate Univ. Ibn Zohr 45000 Ouarzazate Morocco lMTI Faculte des Sciences d’Agadir Universite Ibn Zohr BP 28/S Agadir Morocco

Conventional orthogonal polynomial approach can solve the multilayered plate only when the material properties of two adjacent layers do not change significantly. This paper de- veloped an improved orthogonal polynomial approach to solve wave propagation in multilayered plates with very dissimilar material properties. Through numerical comparisons among the exact solution, the results from the conventional polynomial approach and from the improved poly- nomial approach, the validity of the improved polynomial approach is illustrated. Finally, it is shown that the conventional polynomial approach can not yield correct continuous normal stress profiles. The improved orthogonul polynomial approach has overcome this drawback.

关键词： multilayered plate orthogonal polynomial dispersion curves stress profiles

Crystal Growth of[Ca3Al(OH)6·12H2O]2·(SO4)3·2H2O (Ettringite) Studied Under Microgravity Conditions

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journal of Wuhan University of Technology(Materials Science) 2020年第5期35卷 893-899页

作者： Meier M R lEI l Rinkenburger A Plank j Technische Universitat Miinchen Chair for Construction Chemistry85747 GarchingLichtenbergstrafie 4Germany

On parabolic flights,the growth of ettringite,[Ca3Al(OH)6·12H2O]2·(SO4)3·2H2O,a major reaction product of cement with water which forms instantaneously,was crystallized under microgravity conditions and *** the experiments,Ca(OH)2/Al2(SO4)3 solutions were combined and reacted for 10?s,followed by immediate filtration of the suspension and subsequent quenching with *** the ettringite crystals,the size,aspect ratios,quantity and morphology were determined and the results were compared with those from identical experiments performed under terrestric *** microgravity,generally smaller crystals (l-2.9 μm) precipitated in larger amount than under normal gravity (l-3.5 μm).The aspect ratios of the crystals grown under terrestric or microgravity condition were comparable at about *** is assumed that the reason for the smaller ettringite crystals is the absence of convection leading to more initial nuclei,but slower crystal growth which is diffusion ***,no preference relative to the ion transport to the different faces of the crystals *** results contribute to the understanding of the mineralization of inorganic salts under microgravity conditions for which hitherto only a handful of examples were reported.

关键词： crystallization ettringite microgravity morphology nucleation

A legendre orthogonal moment based 3D edge operator

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Science China(Physics,Mechanics & Astronomy) 2005年第1期48卷 1-13页

作者： j.l.Dillenseger lTSI University of Rennes IFrance

This paper presents a new 3D edge operator based on legendre orthogonal moments. This operator can be used to extract the edge of 3D object in any window size,with more accurate surface orientation and more precise surface location. It also has full geometry meaning. Process of calculation is considered in the moment based *** can greatly speed up the computation by calculating out the masks in advance. We integrate this operator into our rendering of medical image data based on ray casting algorithm. Experimental results show that it is an effective 3D edge operator that is more accurate in position and orientation.

关键词： legendre moment, 3D edge operator, surface location, surface orientation, ray casting.

Development and Electrochemical Studies of Ruthenium Based Mixed Oxide Catalyst Electrodes for Chlorine Evolution

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Chemical Research in Chinese Universities 2002年第2期18卷 133-138页

作者： l.X.Yang j.P.G.Farr Department of Chemical and Processing Engineering University of Newcastle Merz CourtNewcastle upon Tyne NE17RU School of Metallurgy and Materials The University of Birmingham EdgbastonBirmingham B152TTUK

Experimental results are presented which allow comparison of the electrochemical performance of RuO 2/Ti, Ru 0 3 Sn 0 7 O 2/Ti and Ru 0 3 V 0 7 O 2/Ti catalysts prepared on a titanium substrate by thermal decomposition from respective precursors. The highest activity for chlorine evolution is observed on the Ru 0 3 V 0 7 O 2/Ti electrode, lower on Ru 0 3 Sn 0 7 O 2/Ti and least on RuO 2/Ti. Voltammograms obtained in the polarisable region are used to characterize the different electrodes. Further more an analysis of the catalytic activity and reaction kinetics of the developed electrodes in NaCl are presented.

关键词： Catalyst Cl_(2) evolution Ruthenium oxide

Hilbert Space of Probability Density Functions Based on Aitchison Geometry

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Acta Mathematica Sinica,English Series 2006年第4期22卷 1175-1182页

作者： j.j.EGOZCUE j.l.DIAZ-BARRERO V.PAWlOWSKY-GlAHN Applied Mathematics Ⅲ Universitat Politàcnica de CatalunyaJordi Girona 1-3C208034BarcelonaSpain Applied Mathematics Ⅲ Universitat Politàcnica de CatalunyaJordi Girona 13C208034BarcelonaSpain Informatics and Applied Mathematics Universitat de GironaCampus MontiliviP417071GironaSpain

The set of probability functions is a convex subset of l1 and it does not have a linear space structure when using ordinary sum and multiplication by real constants. Moreover, difficulties arise when dealing with distances between densities. The crucial point is that usual distances are not invariant under relevant transformations of densities. To overcome these limitations, Aitchison＇s ideas on compositional data analysis are used, generalizing perturbation and power transformation, as well as the Aitchison inner product, to operations on probability density functions with support on a finite interval. With these operations at hand, it is shown that the set of bounded probability density functions on finite intervals is a pre-Hilbert space. A Hilbert space of densities, whose logarithm is square-integrable, is obtained as the natural completion of the pre-Hilbert space.

关键词： Bayes' theorem Fourier coefficients Haar basis Aitchison distance Simplex least squares approximation