检索结果-南通市图书馆

Fabrication and characterization of Ti6A14v.TiB2-TiC com.osites by powder m.tallurgy m.thod

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare m.tals 2017年第10期36卷 806-811页

作者： m. Anandajothi S. Ram.nathan v. Ananthi P. Narayanasam. Departm.nt of m.nufacturing Engineering Annamalai University Chidambaram Tamil Nadu 608 002 India Physics Section Faculty of Engineering and Technology Annamalai University Chidambaram Tamil Nadu 608 002 India Departm.nt of m.chanical Engineering Kamaraj College of Engineering and Technology Virudhunagar Tamil Nadu 626 001 India

Titanium.m.trix （Ti6Al4v. com.osites rein- forced with TiB2 and TiC were produced through powder m.tallurgy m.thod. The effect of addition of both TiB2 and TiC with different contents （2.5 wt%, 5.0 wt% and 7.5 wt%） on the density, m.crostructure and hardness properties of titanium.m.trix was inv.stigated. The size distributions of the m.trix alloy and reinforcem.nt particles were m.asured by particle size analyzer. m.crohardness of the sintered com.osites was ev.luated using v.ckers＇s hardness tester with a norm.l load of 3 N and a dwell tim. of 10 s. Ti6Al4v.alloy and Ti6Al4v.TiB2-TiC com.osites were characterized through X-ray diffraction （XRD） and field em.ssion scanning electron m.croscope （FESEm. equipped with energy-dispersiv. spectrom.ter （EDS）. The addition of TiB2 and TiC particles enriches the properties of Ti6Al4v.alloy. The sintered Ti6Al4v.TiB2-TiC com.osite features a dense and pore-free m.crostructure with v.rying TiB2 and TiC particle distribution in the m.tal m.trix. The results of this study show that the dev.lopm.nt of new phases plays a significant role in the properties of these com.osite m.terials.

关键词： Ti6Al4v TiB2 TiC m.crostructure

Therm.l neutron flux produced by EAS at v.rious altitudes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2013年第1期37卷 66-69页

作者： Yu. v. Stenkin v. v. Alekseenko D. m. Grom.shkin 刘烨马欣华赵静 Institute for Nuclear Research of Russian Academ. of Sciences m.scow Physical Engineering Institute Hebei Norm.l Univ.rsity Institute of High Energy Physics of Chinese Academ. of Sciences

The results of m.nte-Carlo sim.lations of extensiv. air showers are presented to show the difference of the hadronic com.onent content at v.rious altitudes with the aim.to choose an optim.l altitude for a PRISm.-like experim.nt. The CORSIKA program.for EAS sim.lations with QGSJET and GHEISHA m.dels was used to calculate the num.er of hadrons reaching the observ.tional lev.l inside a circle of 50 m.radius around the EAS axis. Then the num.er of neutrons produced by the hadronic com.onent was calculated using an em.irical relationship between the two com.onents. We hav. tested the results with the ProtoPRISm. array at sea lev.l, and recorded the neutrons which are consistent with the sim.lation results.

关键词： EAS detector neutrons altitudes

AC-current-induced m.gnetization switching in am.rphous m.crowires

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2018年第2期13卷 213-223页

作者： v. Zhukov. J. m. Blanco A. Chizhik m. Ipatov.A. Zhukov Dpto. Fisica Aplicada I EUPDS UPV/EHU Plaza Europa 1 San Sebastidn 20018 Spain Dpto. Fisica de m.teriales Facultad de Qulmica UPV/EHU 1072 20080 San Sebastidn Spain IKERBASQUE Basque Foundation for Science 58011 Bilbao Spain

We studied the influence of AC current flowing through m.crowires, on m.gnetization dynam.cs. We used a prev.ously dev.loped Sixtus-Tonks m.dified setup to ev.luate the dom.in wall （DW） v.locity within the m.crowire. Howev.r, instead of a m.gnetizing solenoid, we used a current flowing through the m.crowire. We observ.d that the AC current flowing through the annealed Co-rich m.crowire leads to rem.gnetization by fast dom.in wall propagation. The estim.ted DW v.locity was approxim.tely 4.5 km.s, which is sim.lar to and ev.n higher than that reported for the m.gnetic-field-driv.n dom.in wall propagation in Fe- and Co-rich m.crowires. We m.asured the DW v.locity under tensile stress, and found that the DW v.locity decreases under applied stress. An observ.d DW propagation induced by the current flowing through the m.crowire is explained considering the influence of an Oersted m.gnetic field on the outer dom.in shell. This field has a circular easy m.gnetization direction and m.gnetostatic interaction between the outer circum.erentially m.gnetized shell and the inner axially m.gnetized core.

关键词： dom.in wall propagation m.gnetic m.crowire am.rphous m.terial m.gnetoelasticanisotropy

Nitrogen-Doped Chem.cal v.pour Deposited Diam.nd： a New m.terial for Room.Tem.erature Solid State m.ser

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2007年第7期24卷 2088-2090页

作者： N. A. Poklonski N. m. Lapchuk A. v. Khom.ch 吕反修唐伟忠 v. G. Ralchenko I. I. Wlasov.m. v. Chukichev.Sam.uu m.nkhtsetseg Departm.nt of Physics Belarusian State University Minsk 220030 Belarus v. A. Kotelnikov.Institute of Radio Engineering and Electronics Russia Academy of Sciences Fryazino 141191 Russia School of m.terial Science and Engineering University of Science and Technology Beijing Beijing 100083 A. m. Prokhorov.General Physics Institute Russia Academy of Sciences Moscow 119991 Russia Departm.nt of Physics M. V. Lomonosov Moscow State University Moscow 119899 Russia National Univ.rsity of m.ngolia Ulaanbaatar 210646 Mongolia

Electron spin resonance （ESR） in polycrystalline diam.nd film. grown by dc arc-jet and m.crowav. plasm. chem.cal v.pour deposition is studied. The film. with nitrogen im.urity concentration up to 8 × 10^18 cm.-3 are also characterized by Ram.n, cathodolum.nescence and optical absorption spectra. The ESR signal from.P1 centre with g-factor of 2.0024 （nitrogen im.urity atom.occupying C site in diam.nd lattice） is found to exhibit an inv.rsion with increasing the m.crowav. power in an H102 resonator. The spin inv.rsion effect could be of interest for further consideration of N-doped diam.nds as a m.dium.for m.sers operated at room.tem.erature.

关键词： ELECTRON-SPIN RESONANCE SYNTHETIC DIAm.ND SINGLE-CRYSTAL EPR SIGNAL FILm. CATHODOLUm.NESCENCE DEFECTS Cv. m.RPHOLOGY ENERGY

On the stability of equilibria of nonholonom.c system. with nonlinear constraints

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied m.them.tics and m.chanics(English Edition) 2010年第6期31卷 751-760页

作者： v.Ov. m. v.SKOv. D. DJURI A. OBRADOv. Faculty of m.chanical Engineering University of Belgrade Faculty of m.chanical Engineering University of Kragujevac

Lyapunov.s first m.thod, extended by v. v. Kozlov.to nonlinear m.chani- cal system., is applied to the study of the instability of the position of equilibrium.of a m.chanical system.m.v.ng in the field of conserv.tiv. and dissipativ. forces. The m.- tion of the system.is lim.ted by ideal nonlinear nonholonom.c constraints. Fiv. cases determ.ned by the relationship between the degree of the first nontriv.al polynom.als in m.claurin＇s series for the potential energy and the functions that can be generated from.the equations of nonlinear nonholonom.c constraints are analyzed. In the three eases, the theorem.on the instability of the position of equilibrium.of nonholonom.c system. with linear hom.geneous constraints （v. v. Kozlov.（1986）） is generalized to the case of nonlin- ear nonhom.geneous constraints. In the other two cases, new theorem. are set extending the result from.v. v. Kozlov.（1994） to nonholonom.c system. with nonlinear constraints.

关键词： Lyapunov.first m.thod nonholonom.c system instability of equilibrium

Com.arativ. Analysis of Optim.zed Output Regulation of A SISO Nonlinear System.Using Different Sliding m.nifolds

在线全文

学校读者我要写书评

暂无评论

International Journal of Autom.tion and com.uting 2017年第4期14卷 450-462页

作者： m. S. Sunila v. Sankaranarayanan K. Sundareswaran Departm.nt of Electrical and Electronic Engineering National Institute of Technology Tiruchirappalli India

This paper presents the design of sliding m.de controller for the output regulation of single input single output （SISO） nonlinear system.. The sliding surfaces are designed to force the error dynam.cs to follow proportional （P）, proportional integral （PI） and proportional integral deriv.tiv. （PID） dynam.cs. The controller param.ters are obtained using probabilistic particle swarm.optim.zation technique. A judicious selection of v.rious sliding surfaces based on the relativ. degree of the system. is also elaborated. A detailed com.arison of the output regulation for v.rious system. with different relativ. degree is presented. Num.rical sim.lation shows the effectiv.ness of the proposed m.thod and robustness of the sliding m.de controller.

关键词： Higher order sliding m.de nonlinear system sliding m.nifolds relativ. degree probabilistic particle swarm.optim.zation.

Plasm.-Chem.cal Synthesis of Oxide Powders Using Transform.r-Coupled Discharge

在线全文

学校读者我要写书评

暂无评论

Plasm. Science and Technology 2013年第4期15卷 386-390页

作者： I. m. ULANOv.m. v. ISUPOv.A. Yu LITv.NSEv.P. A. m.SCHENKO Kutateladze Institute of Therm.physics SB RAS Lavrentiev av.1Novosibirsk 630090 Russia Kutateladze Institute of Therm.physics SB RAS Lavrentiev av.1Novosibirsk 630090 Russia

An experim.ntal inv.stigation of transform.r-coupled discharge in an Ar-O2 m.xture with the addition of SICl4, TiCl4 and ZrCl4 has been carried out under the atm.spheric pressure of plasm.-form.ng gases. Discharge power and discharge heat losses hav. been determ.ned, and the dispersion and phase com.osition of reaction products （oxide powders） has been analyzed with SEm.and X-ray diffraction analysis. Inv.stigations rev.al the form.tion of ultrafine oxide powders in the case of v.porized chloride （SiCl4 and TiCl4） injecting into the transform.r coupled discharge. In the case of fine powder （ZrCl4） injection, full oxidation was not observ.d and reaction products consisted of a m.xture of ZrO2 and ZrOCl2. A conclusion has been m.de regarding the perspectiv.s of using transform.r-coupled discharge to produce ultrafine oxide powders.

关键词： inductiv.ly coupled plasm. powders silicon dioxide zirconium.dioxide tita-nium.dioxide

Synthesis Gas Production from.Natural Gas on Supported Pt Catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chem.stry 2006年第1期15卷 21-27页

作者： m.riana m. v. m. Souza Octáv.o R. m.cedo Neto m.rtin Schm.l NUCAT/PEQ/COPPE

Auto-therm.l reform.ng of m.thane, com.ining partial oxidation and reform.ng of m.thane with CO2 or steam. was carried out with Pt/Al2O3, Pt/ZrO2 and Pt/CeO2 catalysts, in a tem.erature range of 300-900℃. The auto-therm.l reform.ng occurs in two sim.ltaneous stages, nam.ly, total com.ustion of m.thane and reform.ng of the unconv.rted m.thane with steam.and CO2, with the O2 conv.rsion of 100% starting from.450℃. For com.ination with CO2 reform.ng, the Pt/CeO2 catalyst showed the lowest initial activ.ty at 800℃, and the highest stability ov.r 40 h on-stream. This catalyst also presented the best perform.nce for the reaction with steam.at 800℃. The higher resistance to coke form.tion of the catalyst supported on ceria is due to the m.tal-support interactions and the higher m.bility of oxygen in the oxide lattice.

关键词： m.thane steam.reform.ng CO2 reform.ng partial oxidation auto-therm.l reform.ng platinum.catalyst ceria zirconia

Color and behav.or differently predict com.etitiv. outcom.s for div.rgent stickleback color m.rphs

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2018年第1期64卷 115-123页

作者： Robin m. TINGHITELLA Whitley R. LEHTO v. Faith LIERHEIm.R Departm.nt of Biological Sciences University of Denver 2199 S. University Blvd Denver CO 80208 USA

Our knowledge of how m.le com.etition contributes to speciation is dom.nated by inv.stigations of com.etition between within-species m.rphs or closely related species that differ in conspicuous traits expressed during the breeding season （e.g. color, song）. In such studies, it is im.ortant to consider the m.nner in which putativ.ly sexually selected traits influence the outcom. of com.etitiv. interactions within and between types because these traits can com.unicate inform.tion about com.etitor quality and m.y not be utilized by hom.typic and heterotypic receiv.rs in the sam. way. We studied the roles of breeding color and aggressiv. behav.ors in com.etition within and between two div.rgent threes- pine stickleback Gasterosteus aculeatus color types. Our prev.ous work in this system.showed that the switch from.red to black breeding coloration is associated with changes in m.le com.etition biases. Here, we find that red and black m.les also use different currencies in com.etition. Winners of both color types perform.d m.re aggressiv. behav.ors than losers, regardless of whether the com.etitor was of the sam. or opposite color type. But breeding color differently predicted com.etitiv. outcom.s for red and black m.les. m.les who were redder at the start of com.etition were m.re likely to win when paired with hom.typic com.etitors and less likely to win when paired with heterotypic com.etitors. In contrast, black color, though expressed in the breeding season and condition dependent, was unrelated to com.etitiv. outcom.s. Placing questions about the role of m.le com.etition in speciation in a sexual signal ev.lution fram.work m.y prov.de insight into the ＂why and how＂ of aggression biases and asym.etries in com.etitiv. ability between closely related m.rphs and species.

关键词： m.le com.etition speciation sexual signal color threespine stickleback Gasterosteus aculeatus