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MECHANISM AND KINETICS OF TRANSFORMATION OF AluMINA INCluSIONS BY CAlCIuM TREATMENT

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Acta Metallurgica Sinica(English letters) 2006年第1期19卷 1-8页

作者： Z.j. Han l. liu M. lind l. Holappa Central Iron and Steel Research Institute Beijing 100081 China laboratory of Metallurgy Helsinki University of Technology P.O. Box 6200Espoo 02015 Finland

The basic mechanism and kinetics of the transformation process of alumina inclusions in steel was reported when calcium introduced into the steel by wire feeding orpowder injection. To clarify the mechanisms model, experiments were performed by studying reactions between AltOs and CaO in a laboratory furnace and by performing calcium treatments in an 8kg induction furnace for Al deoxidised melt. The phases formed during the reaction between Al2O3 and CaO were examined by SEM-EDS （scanning electron microscope-energy dispersive spectrometer）, and the reaction sequence of Al2O3=〉 CA6=〉 CA2 =〉 CA =〉 CAx（l） was discussed in term of the experimental observations. The kinetics of the reaction of calcium with alumina inclusions were simulated by immersing alumina plates in a Ca treated steel melt in the induction furnace. Results were compared with observations of real inclusion transformation. A kinetic model was proposed based on the results.

关键词： mechanism kinetics alumina inclusion transformation

Corrosion testing of X52 and X80 steels immersed in stimulated emulsions using a real petroleum sample

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Petroleum Research 2024年第2期9卷 304-316页

作者： l.M.Quej-Ake j.l.Alamilla A.Contreras Instituto Mexicano del Petróleo Eje Central Lázaro CárdenasNorte 152San Bartolo AtepehuacanGustavo A.MaderoCiudad de MéxicoC.P.07730México

The aim of this study is to evaluate the internal corrosion process on X52 and X80 steels/real petroleum interfaces containing condensed hydrocarbon plus oilfield-produced water,which were subjected to stimulated emulsions using 50/50 vol ratio mixtures at 45℃,different hydrodynamic conditions,1 h,and 24 h.A washing process by using deionized water was proposed to simulate and identify the corrosiveness of the hydrocarbon phase after 24 h of exposure *** characterization by electrochemical impedance spectroscopy and the monitoring of the polarization curves indicated that X80 steel/oilfield-produced water interfaces were more susceptible to corrosion than X52 steel exposed to oilfield-produced *** combined speed rotation of 600 rpm using a magnetic stirrer+600 rpm using a rotating disk electrode decreased the corrosion rate on X52 *** stimulated emulsions made of hydrocarbon+oilfield-produced water and hydrocarbon+deionized water at 24 h increased the corrosion rate on X80 steel(0.34 mm/year and 0.43 mm/year,respectively),promoting the formation of erosion and pitting *** types of corrosion depended mainly on the physicochemical properties of the hydrocarbon,oilfield-produced water,exposure times,and hydrodynamic systems in which the hydrocarbon was studied.

关键词： Corrosion Emulsions X52 steel X80 steel

Approach for electrodynamic force for compensation in low voltage circuit breaker WP 630-1.2 type

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journal of Zhejiang university-Science A(Applied Physics & Engineering) 2007年第3期8卷 393-396页

作者： lu Na Xu l.j Miedzifiski B Automation School Beijing University of Posts and Telecommunications Beijing 100876 China Electrical Power Engineering Institute Wroclaw University of Technology Wroclaw Poland

undesirable repulsive force between contact members due to both a current path shrink near a real contact area and/or so-called pinch effect is particularly onerous for power switch applications, and results in either contact floating or bouncing which are associated with an electric arc following contact welding. This problem is of great importance for any circuit breaker especially for compact low voltage vacuum circuit breakers. To avoid contact floating at closure and during any inrush current under short circuit conditions, the electrodynamic repulsive force can be employed successfully if we use a special compensation system flexibly combined with the contact itself. However to select and design the compensation system properly, its efficiency has to be known. This paper presents an approach to obtain the electrodynamic force value depending on different shaped (rectangular, square, circle and arch) copper plates used in the compensator by using ANSYS for current values 40 kA RMS. Curve-fitting was done according to the calculating results, the optimization designing of compensation unit is based on them.

关键词： Compensation. Electrodynamic force. FEM (Finite Element Method)

On the origin of X-shaped radio galaxies

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Research in Astronomy and Astrophysics 2012年第2期12卷 127-146页

作者： Gopal-Krishna Peter l.Biermann lszló .Gergely Paul j.Wiita National Centre for Radio Astrophysics TIFRPune University Campus Max Planck Institute for Radioastronomy Department of Physics & Astronomy University of Bonn Department of Physics & Astronomy University of Alabama Department of Physics University of Alabama at Huntsville KIT-Karlsruhe Institute for Technology Institute for Experimental Nuclear Physics Department of Theoretical Physics University of Szeged Department of Experimental Physics University of Szeged Department of Physics The College of New Jersey

After a brief, critical review of the leading explanations proposed for the small but important subset of radio galaxies showing an X-shaped morphology （XRGs） we propose a generalized model, based on the jet-shell interaction and spin- flip hypotheses. The most popular scenarios for this intriguing phenomenon invoke either hydrodynamical backflows and over-pressured cocoons or rapid jet reorienta- tions, presumably from the spin-flips of central engines following the mergers of pairs of galaxies, each of which contains a supermassive black hole. We confront these models with a number of key observations, and thus argue that none of the models is capable of explaining the entire range of the salient observational properties of XRGs, although some of the arguments raised in the literature against the spin-flip scenario are probably not tenable. We then propose a new scenario which also involves galac- tic mergers but would allow the spin of the central engine to maintain its direction. Motivated by detailed multi-band observations of the nearest radio galaxy, Centaurus A, this new model emphasizes the role of the interactions between the jets and the shells of stars and gas that form and rotate around the merged galaxy and can cause temporary deflections of the jets, occasionally giving rise to an X-shaped radio struc- ture. Although each model is likely to be relevant to a subset of XRGs, the bulk of the evidence indicates that most of them are best explained by the jet-shell interaction or spin-flip hypotheses.

关键词： galaxies: active - galaxies: jets - gravitational waves - ISM - radiocontinuum: galaxies

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

Chemically reactive and radiative von Kármán swirling flow due to a rotating disk

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Applied Mathematics and Mechanics(English Edition) 2018年第9期39卷 1295-1310页

作者： M.KHAN j.AHMED l.AHMAD Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Basic Sciences University of Engineering and TechnologyTaxila 47050Pakistan Department of Mathematics Shaheed Benazir Bhutto UniversitySheringal Upper Dir 18000Pakistan

A new mathematical model is presented to study the heat and mass transfer characteristics of magnetohydrodynamic(MHD) Maxwell fluid flow over a convectively heated stretchable rotating disk. To regulate the fluid temperature at the surface, a simple isothermal model of homogeneous-heterogeneous reactions is employed. The impact of nonlinear thermal radiative heat flux on thermal transport features is studied. The transformed nonlinear system of ordinary differential equations is solved numerically with an efficient method, namely, the Runge-Kutta-Felberg fourth-order and fifth-order(RKF45)integration scheme using the MAPlE software. Achieved results are validated with previous studies in an excellent way. Major outcomes reveal that the magnetic flux reduces the velocity components in the radial, angular, and axial directions, and enhances the fluid temperature. Also, the presence of radiative heat flux is to raise the temperature of fluid. Further, the strength of homogeneous-heterogeneous reactions is useful to diminish the concentration of reaction.

关键词： rotating stretchable disk magnetic field nonlinear radiative heat flux homogeneous-heterogeneous chemical reaction

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

Different Diffusion Behavior of Cu and Ni undergoing liquidesolid Electromigration

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journal of Materials Science & Technology 2014年第12期30卷 1235-1242页

作者： M.l.Huang Z.j.Zhang H.T.Ma l.D.Chen Electronic Packaging Materials laboratory School of Materials Science & Engineering Dalian University of Technology IC Packaging Department Xi'an Institute of Microelectronic Technology

The diffusion behavior of Cu and Ni atoms undergoing liquidesolid electromigration（l-S EM） was investigated using Cu/Sn/Ni interconnects under a current density of 5.0 103A/cm2 at 250℃. The flowing direction of electrons significantly influences the cross-solder interaction of Cu and Ni atoms, i.e., under downwind diffusion, both Cu and Ni atoms can diffuse to the opposite interfaces; while under upwind diffusion,Cu atoms but not Ni atoms can diffuse to the opposite interface. When electrons flow from the Cu to the Ni, only Cu atoms diffuse to the opposite anode Ni interface, resulting in the transformation of interfacial intermetallic compound（IMC） from Ni3Sn4into（Cu,Ni）6Sn5and further into [（Cu,Ni）6Sn5t Cu6Sn5], while no Ni atoms diffuse to the opposite cathode Cu interface and thus the interfacial Cu6Sn5 *** electrons flow from the Ni to the Cu, both Cu and Ni atoms diffuse to the opposite interfaces,resulting in the interfacial IMC transformation from initial Cu6Sn5into（Cu,Ni）6Sn5and further into[（Cu,Ni）6Sn5t（Ni,Cu）3Sn4] at the anode Cu interface while that from initial Ni3Sn4into（Cu,Ni）6Sn5and further into（Ni,Cu）3Sn4at the cathode Ni interface. It is more damaging with electrons flowing from the Cu to the Ni than the other way.

关键词： Cu/Sn/Ni Electromigration Cross-solder interaction Interfacial reaction Diffusion

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 li 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