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Journal of Materials Science & Technology 2012年第11期28卷 1046-1052页

作者： R.l.lju y.J.Qiao M.F.yan y.d.Fu College of Materials Science and Chemical Engineering Harbin Engineering UniversityHarbin 150001China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

low temperature plasma nitrocarburizing of 17-4PH martensitic stainless steel was conducted at 430 ℃ with and without rare earth （RE） addition. The microstructure, kinetics, microhardness, wear behavior as well as corrosion resistance of the modified layer were studied by optical microscopy, X-ray diffraction, Vickers microhardness tester, pin-on-disc tribometer and potentiodynamic polarization tests. The results show that the thickness of plasma RE nitrocarburized layer is much thicker than that formed by nitrocarburizing without RE addition. The incorporation of RE does not change the kind of the phases and the nitrocarburized layer consists mainly of nitrogen and carbon expanded martensite （aN）, γ-Fe4N and a-Fe with a trace of CrN phases. The surface microhardness of plasma nitrocarburized layer can be increased by 100 HV after RE addition. Wear resistance of the specimen can be apparently improved by low temperature plasma nitrocarburizing with and without RE addition and without sacrificing its corrosion resistance. Wear reduction effect of low temperature plasma nitrocarburizing with RE addition is better than that of the conventional one.

关键词： Stainless steel low temperature Plasma nitrocarburizing Rare earth (RE) Wear and friction

Friction Stir Welding of discontinuously Reinforced Aluminum Matrix Composites:A Review

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Acta Metallurgica Sinica(English letters) 2014年第5期27卷 816-824页

作者： d.Wang B.l.Xiao d.R.Ni Z.y.Ma Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

Friction stir welding （FSW） is considered a promising welding technique for joining the aluminum matrix composites （AMCs） to avoid the drawbacks of the fusion welding. High joint efficiencies of 60%-100% could be obtained in the FSW joints of AMCs. However, due to the existence of hard reinforcing particles in the AMCs, the wearing of welding tool during FSW is an unavoidable problem. Moreover, the low ductility of the AMCs limits the welding process window. As the hard materials such as Ferro-Titanit alloy, cermet, and WC/Co were applied to produce the welding tools, the wearing of the tools was significantly reduced and the sound joints could be achieved at high welding speed for the AMCs with low reinforcement volume fraction. In this article, current state of understanding and development of welding tool wearing and FSW parameters of AMCs are viewed. Furthermore, the factors affecting the microstructure and mechanical properties of the joints are evaluated in detail.

关键词： Metal matrix composite Friction stir welding Particle, microstructure Wear

Active Network Supports for Mobile IP

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Journal of Computer Science & Technology 2001年第6期16卷 544-551页

作者： lu, y. Qian, d. Xu, B. Wang, l. dept. of Computer Science and Eng. Xi'an Jiaotong University Xi'an 710049 China

The basic mobile IP protocol is difficult to implement on the traditional IP network and not flexible and efficient under certain conditions. For example, firewalls or bound- ary routers may drop packets sent by mobile nodes for security reasons. Traditional networking devices such as routers cannot dynamically load and unload extended services to achieve differ- ent qualities of services. In this paper, a new scheme of using the active network to support the mobile IP is presented. The Softnet, a prototype of active networks based on mobile agents, is introduced. The active network is characterized by the programmability of its intermediate nodes and therefore presents dynamic and flexible behaviors. Special services can be dynam- ically deployed onto the active nodes in the Softnet. This property is definitely required in implementing the mobile IP protocols. The Softnet supports not only the basic mobile IP pro- tocol but also other extended mobiIe IP protocols. Virtual networks for mobile IP services are dynamically formed by mobile agents in the Softnet to provide different qualities of services.

关键词： mobile IP Softnet active network mobile agent virtual network

Numerical simulation and experiment of error field measurement using luminous trace of electron beam in SST-1

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Plasma Science and Technology 2019年第10期21卷 9-16页

作者： Someswar duTTA y PARAVASTu J dHONGdE H CHudASMA S GEORGE K dHANANI A MAKWANA C dOdIyA P VARMORA d K SHARMA A K SINGH u KuMAR d RAVAl u PRASAd Z KHAN R SRINIVASAN d RAJu Institute for Plasma Research GandhinagarGujrat 382428India Homi Bhabha National Institute (HBNI) AnushaktinagarMumbai 400094India

In contrast to the earlier experiments conducted in other machines, here, in SST-1 the error field measurement experiment is performed with a filled gas pressure ~8×10^-4 mbar which helped to create a luminescent toroidal beam of electron path originated due to impact excitation and guided by the toroidal magnetic field. Beam path deviations are observed and recorded from radial and top ports using visible range cameras. Such creation and detection of the electron beam path differs from the earlier works where the gun emitted electron beam deviation in ultrahigh vacuum was detected on a collector-grid/fluorescent screen. In the present experiment, large beam deviations were observed. later investigation of the experimental set-up reveals existence of a possible source of radial electric field in between the source and the vacuum vessel which are separately grounded. Thus, to understand the observed phenomena, experiments are numerically modeled with deviated TF coil set, PF coil set and the electron source location. A particle tracing code is used to follow the electron path in the magnetic field generated by the coil set of interest. Simulation results suggest that the large deviation corresponds to the E×B drifts and not due to the large field errors. Toroidally averaged field errors of the SST-1 TF coils at toroidal field of B0?=?15 kG are negligibly small ~B0?×?10^-6 or less, which should not adversely affect the plasma performance.

关键词： electron beam error field SST-1 TF coil

Synthesis and Crystal Structure of Trans-bis(acesulfamato-O)tetraaquazinc(Ⅱ)

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Chinese Journal of Structural Chemistry 2010年第7期29卷 1047-1050页

作者： SAHIN Onur ICBudAK Hasan B(u|¨)y(u|¨)KG(u|¨)NG(O|¨)R Orhan department of Physics Faculty of Arts and SciencesOndokuz Mayis UniversitySamsunTurkey department of Chemistry Faculty of Arts and SciencesOndokuz Mayis UniversitySamsunTurkey

The title compound, trans-bis（acesulfamato-O）tetraaquazinc（Ⅱ）（I, C8H16N2O12S2Zn）, crystallizes in the triclinic system, space group P1 with a = 5.1638（5）, b = 8.5338（9）, c = 9.9583（9）A, α = 74.325（8）, β = 81.112（7）, γ = 75.800（8）°, V= 407.77（7） A3, Z = 1, F（000） = 236, Rint = 0.085, T= 296 K, the final R = 0.029 and wR = 0.078 for 1832 observed reflections with I〉 2σ（0. The ZnⅡcentre resides on a centre of symmetry and has a distorted octahedral geometry. The basal plane is defined by two carbonyl O atoms of two monodentate trans-oriented acesulfamato ligands and two trans-aqua ligands. The axial positions in the octahedron are occupied by two trans-aqua ligands. Intermolecular O-H…O hydrogen bonds produce R22（8） and R22（16） rings, which lead to two- dimensional polymeric chains.

关键词： crystal structure zinc(Ⅱ) octahedral complex hydrogen bonds

Study of K^(*)(892)^(0)andФ(1020)meson production in proton–proton and Pb–Pb collisions at√S_(NN)=2.76 TeV

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Communications in Theoretical Physics 2021年第2期73卷 89-95页

作者： y Ali M Ahmed A Arif Q Ali u Tabassam u Rubab M Suleymanov department of Physics COMSATS UniversityPark RoadIslamabad44000Pakistan Institute for Physical Problems Baku Suate UniversityBakuAZ 1000Azrbajan

In this paper,we describe a study of charged particle yield as a function of pT for K^(*)(892)0 and phgr(1020)mesons in proton–proton(pp)and Pb–Pb collisions at√S_(NN)=2.76 TeV in the central rapidity region of|y|llisions and in a pT range of 0lso investigated a very important ratio,the nuclear modification factor,to study the effects of the medium in the most central region,i.e.0%–5%*** data simulation,we used the EPOS-lHC and EPOS-1.99 *** check the validity of these models'simulations,we compared the data obtained from these Monte Carlo simulation programs with AlICE experimental data for√S_(NN)=2.76 *** was concluded that the models'predictions for the phgr-meson in pp and for the most central Pb-Pb collisions disagreed with the AlICE data,and that the difference increased with *** may be connected with the essential role of collective parton behaviors which could not have been taken into account by the *** K^(*)0 mesons,both programs gave almost the same predictions,and with pT in the interval pT>3 GeV c^(−1),the predictions were very close to the experimental *** models gave higher predictions for the soft pT interval and lower predictions for the hard *** values of the RAA distributions were lower than unity and both models were very close to the AlICE *** is very interesting that the models were not able to describe the pT distributions,but they gave good predictions for their *** may possibly be due to parton collective *** observed some additional suppression of K^(*)0 at low values of pT with respect to phgr-mesons,which may be related to the role of the masses of the particles in soft *** rising trend for R_(AA)in the region from pT=10 GeV c^(−1)to 20 GeV c^(−1) observed by the AlICE experiment was absent for theФ-mesons.

关键词： Quark Gluon Plasma EPOS-lHC nuclear modification factor

Wear of semi-solid rheocast SiC_p/Al metal matrix composites

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中国有色金属学会会刊：英文版 2010年第S3期20卷 852-856页

作者： u.A.CuRlE l.IVANCHEV Materials Science and Manufacturing Council for Scientific and Industrial Research(South Africa)

Rheocasting of plates in Al alloy 359 reinforced with SiC at 11%,27% and 50%(volume fractions) exhibits the capability of the council for scientific and industrial research-rheocasting system(CSIR-RCS) in rheo-processing and high pressure die casting of SiC metal matrix *** metal matrix consisting of nearly spherical proeutectic α(Al) globules was *** of fibrous eutectic silicon took place upon heat treatment of the as-cast metal matrix composites(MMCs).Hardness increases as the volume fractions of SiC *** rates of the MMCs in the F and T6 heat treatment conditions were assessed with a metallographic preparation *** is found that the 11% SiC MMC wear rate is higher on SiC abrasives compared with the 50% SiC MMC wear rate due to wear of the aluminum *** trend is reversed on diamond abrasives due to pull-out of the irregular shaped composite *** 50% SiC MMC suffers from composite particle fracture porosity after high pressure die casting(HPdC).

关键词： CSIR-RCS HPdC SiC F condition T6 condition wear rate hardness porosity

Effect of Temperature on Material Transfer Behavior at different Stages of Friction Stir Welded 7075-T6 Aluminum Alloy

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Journal of Materials Science & Technology 2013年第10期29卷 955-960页

作者： S.d.Ji y.y.Jin y.M.yue S.S.Gao y.X.Huang l.Wang Faculty of Aerospace Engineering Shenyang Aerospace University State Key laboratory of Advanced Welding and Joining Harbin Institute of Technology

In this work, the morphologies of weld of 7075-T6 aluminum alloy via friction stir welding （FSW） were analyzed by optical microscopy, the temperature field was attained by numerical simulation, and the effect of temperature on material transfer behavior in the thermal-mechanical affected zone （TMAZ） at different stages was mainly investigated. The FSW process consists of three stages. It is very interesting to find that the maximum transfer displacement of material appears at the final stage of welding process, then at the stable stage and at the initial stage, which results from the difference of peak temperatures at different stages. At any stage, the material in TMAZ near the surface of weld transfers downwards, the material in the middle of weld moves upwards and the material near the bottom of weld hardly moves. In any cross section of weld, the largest transfer displacement of material appears in the middle of weld. The increase of rotational velocity and the decrease of welding speed are both beneficial to the transfer displacement of material in the middle of weld.

关键词： Friction stir welding 7075-T6 aluminum alloy Thermal-mechanical affected zone Material transfer Numerical simulation

On the detection of closed orbits in time-dependent systems by using double-pulse lasers

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Communications in Theoretical Physics 2020年第9期72卷 111-117页

作者： S u Khan M l du Institute of Theoretical Physics Chinese Academy of Sciences.Beijing 100190China university of Chinese Academy of Sciences Beijing100049China

In the photodetachment of atoms or negative ions by a double-pulse laser, the first pulse of the double-pulse laser generates waves and the delayed second pulse may detect them. The phenomenon of the excitation and detection of waves by a double-pulse laser can be used to identify the closed orbits in the system. We demonstrate this phenomenon with a negative hydrogen ion(H^-) by analyzing the total population excited by a double-pulse laser in a timedependent field for different physical parameters. By analyzing the total excited population using a double-pulse laser, we can uncover all the closed orbits existing in the system. We demonstrate that this can be realized by scanning the first pulse position and the time delay between the two pulses.

关键词： double-pulse laser detection of closed orbits photodetachment spectra time-dependent systems

Oligodendroglial heterogeneity in health,disease,and recovery:deeper insights into myelin dynamics

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Neural Regeneration Research 2025年第11期20卷 3179-3192页

作者： Pieter-Jan Serneels Julie d.de Schutter lies de Groef lieve Moons Steven Bergmans Ku leuven Leuven Brain InstituteDepartment of BiologyAnimal Physiology and Neurobiology DivisionNeural Circuit Development&Regeneration Research GroupLeuvenBelgium Ku leuven Leuven Brain InstituteDepartment of BiologyAnimal Physiology and Neurobiology DivisionCellular Communication&Neurodegeneration Research GroupLeuvenBelgium

decades of research asserted that the oligodendroglial lineage comprises two cell types:oligodendrocyte precursor cells and ***,recent studies employing single-cell RNA sequencing techniques have uncovered novel cell states,prompting a revision of the existing *** forward,the oligodendroglial lineage should be delineated into five distinct cell states:oligodendrocyte precursor cells,committed oligodendrocyte precursor cells,newly formed oligodendrocytes,myelin-forming oligodendrocytes,and mature *** new classification system enables a deeper understanding of the oligodendroglia in both physiological and pathological *** this uniform terminology will facilitate comparison and integration of data across ***,including the consolidation of findings from various demyelinating models,is essential to better understand the pathogenesis of demyelinating ***,comparing injury models across species with varying regenerative capacities can provide insights that may lead to new therapeutic strategies to overcome remyelination ***,by standardizing terminology and synthesizing data from diverse studies across different animal models,we can enhance our understanding of myelin pathology in central nervous system disorders such as multiple sclerosis,Alzheimer's disease,and amyotrophic lateral sclerosis,all of which involve oligodendroglial and myelin dysfunction.

关键词： animal models demyelination fish mammals multiple sclerosis myelin neurodegeneration oligodendrocytes oligodendroglial lineage remyelination