检索结果-南通市图书馆

The Classification of Filiform Leib.iz Superalgeb.as of Nilindex n+m

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2009年第2期25卷 171-190页

作者： sh.A.AYUPOV b.A.OMIROV A.Kh.KHUDOYb.RDIYEV Institute of Mathematics and Information Technologies of Academy Sciences of Uzb.kistan Department of Mathematics National University of Uzbekistan

In this work the classification of filiform Leib.iz superalgeb.as of nilindex n ＋ m, where n and m （m≠0） are dimensions of even and odd parts, respectively, is ob.ained.

关键词： Lie superalgeb.as Leib.iz superalgeb.as nilpotency characteristic sequence

MULTIPLICATION OPERATORS ON INVARIANT SUb.PACES OF FUNCTION SPACES

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2013年第5期33卷 1463-1470页

作者： b.YOUSEFI sh.KHOshDEL Y.JAHANshAHI Department of Mathematics Payame Noor University

Let Mφ b. the operator of multiplication b. φ on a Hilb.rt space of functions analytic on the open unit disk. For an invariant sub.pace F for the multiplication operator Mz, we derive some spectral properties of the multiplication operator Mφ ： F→F. We characterize norm, spectrum, essential norm and essential spectrum of such operators when F has the codimension n property with n∈{1,2,...,＋∞}.

关键词： invariant sub.pace Hilb.rt space of analytic functions essential spectrum essential norm Fredholm operator multiplication operator

Characteristic Assessment of Stab.lized Polyacrylonitrile Nanoweb. for the Production of Activated Carb.n Nano-Sorb.nts

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2014年第4期32卷 449-457页

作者： S.Rafiei b.Noroozi sh.Arb.b.A.K.Haghi Department of Textile Engineering University of Guilan

Polyacrylonitrile （PAN） nanofib.rs with average diameter of 300 nm were produced b. electro-spinning. The nanofib.rs were stab.lized at different temperatures in the range of 180-270 ℃in several duration times and heating rates. Fourier transforms infrared （FTIR） spectroscopy, differential scanning calorimetry （DSC） and X-ray diffraction （XRD） analyzing techniques were employed to measure the extent of stab.lization reaction. b. all procedures, the ranges of temperature and duration time recommended were ab.ut 250-270 ℃ and 1-2 h, respectively. Increasing the activation temperature from 800 ℃ to 1200 ℃ caused porosity and pore volume development up to 60% and 0.532 cm3/g, respectively. Pore width of all samples was calculated to b. ab.ut 0.7 nm confirming micro-pore structure of the produced PAN b.sed activated carb.n nanofib.rs. Comparing dye adsorption for different adsorb.nts including chitin and granular activated carb.n （GAC） showed the highest efficiency for the produced activated carb.n nanofib.rs （ACNFs）.

关键词： Polyacrylonitrile Electro-spinning Stab.lization Activated carb.n nanofib.rs Adsorb.nt.

Influences of sub.trate temperature on microstructure and corrosion b.havior of APS Ni_(50)Ti_(25)Al_(25) inter-metallic coating

在线全文

学校读者我要写书评

暂无评论

Chinese Physics b 2018年第2期27卷 607-612页

作者： sh Khandanjou M Ghoranneviss sh Saviz M Reza Afshar Plasma Physics Research Center Science and Research Branch Islamic Azad University Department of Materials Engineering Science and Research Branch Islamic Azad University

In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carb.n steel *** the coating process, the sub.trate is heated to temperature ranging from room temperature to 400℃. The microstructure, porosity, microhardness, adhesion strength, and corrosion b.havior of the coating are investigated at different sub.trate temperatures. Results show that coating porosity is lower on high temperature surface. Microhardness and adhesion strength of the deposition layer on the sub.trate without preheating have lower values than with preheating. The polarization test result shows that corrosion performance of the coating is dependent on micro cracks and porosities and the increasing of sub.trate temperature can improve the quality of coating and corrosion performance.

关键词： Ni50Ti25Al25 coating air plasma spray planetary b.ll milling inter-metallic compounds corrosion resistance

Solving two-dimensional Volterra-Fredholm integral equations of the second kind b. using b.rnstein polynomials

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2017年第1期32卷 68-78页

作者： M.sh.Dahaghin sh.Eskandari Department of Mathematics Shahrekord University Shahrekord Iran

In this paper, we present a numerical method for solving two-dimensional VolterraFredholm integral equations of the second kind（2DV-FK2）. Our method is b.sed on approximating unknown function with b.rnstein polynomials. We ob.ain an error b.und for this method and employ the method on some numerical tests to show the efficiency of the method.

关键词： Volterra approximating approximate variational proof iterative uniformly exact wavelet inequality

IMPORTANCE OF MOIST AMb.ENT AND ITS HELICAL ENHANCEMENT EFFECT TO STORM INTENSITY

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2004年第6期16卷 743-755页

作者： Al-FALAHI Fadha sh. Key Lab.ratory of Mesoscale Severe Weather Ministry of Education Department of Atmospheric Sciences Nanjing University Nanjing 210093 China

A crucial issue in evolution of severe storm, such as typhoon and even singlesupercell, is to diagnose and predict the sudden intensifying in storm. This paper describ.s anattempt to investigate the influence and effect of amb.ent moisture in the development of storm. Itwas mainly through a dynamic way to detect the helical enhancement b. amb.ent moisture. It was foundthat the correlation b.tween the amb.ent moistness and the intensity of rotating convective cellscan b. well analyzed b. helicity dynamics. The correlation b.tween environmental streamwisevorticity (i. e. helicity) and vertical velocity (storm updraft or downdraft) is a powerfulindicator to catch favorab.e or unfavorab.e conditions for storm evolution. For this purpose, athree-dimensional non-hydrostatic storm-scale model, Advanced Regional Prediction System CARPS) wasemployed in order to numerically simulate a well-documented case of Del City supercell storm indifferent kinds of environmental moistness. Moreover, such different kinds of amb.ent moistenvironment and the resultant different morphologies and evolutions in the storm clearlydemonstrated that the ab.ndant moistness in the environment that the storm emb.dded significantlystrengthens tb. storm intensity. In fact, the storm is emb.dded in much moist environment andtherefore larger instab.lity propagates faster than the one in the drier air. It further producesstronger low-level mesocyclone with a much longer lifetime. The stronger convection and twist in theupdraft indicates that helical enhancement effect b. moisture lead to stronger tornadic activity insevere storm.

关键词： moist amb.ent intensity of storm helical enhancement

The Effect of Injected Air b.b.le Size on the Thermal Performance of a Vertical shell and Helical Coiled Tub. Heat Exchanger

在线全文

学校读者我要写书评

暂无评论

Energy Engineering 2021年第6期118卷 1595-1609页

作者： Saif S.Hasan Ali sh.b.qir Hameed b.Mahood Engineering Technical College Al-Furat Al-Awsat Technical UniversityAl-Najaf31001Iraq Department of Chemical and Process Engineering Faculty of Engineering and Physical SciencesUniversity of SurreyGuildfordGU27XHUK

In the present study,the effect of injecting air b.b.le size on the thermal performance of a vertical counter-current shell and coiled tub. heat exchanger is experimentally *** experiments were accomplished in a cylindrical shape heat exchanger with a 50 cm height and 15 cm outer *** coil with 3.939 m equivalent length and 0.6 cm outer diameter was used to carry the hot fluid(water).Four different cold fluid(shell side)flow rates(Q_(s)=2;4;6 and 8 LPM)Þunder laminar flow conditions(316≤Re≤1223),constant hot(coil side)flow rate fluid rates(Q_(h)=1 LPM),four different injected air flow rates(Q_(a)=0:5;1;1:5 and 2 LPM),invariant temperature difference(ΔT=20°C),and constant b.b.le’s numb.r(1400)were *** demonstrate the effect of b.b.le size,a sparger with orifice diameters of 0.1,0.8,and 1.5 mm was manufactured and used in the *** overall heat transfer coefficient(U),NTU,effectiveness,and pressure loss were *** experimental results clearly showed that the heat exchanger’s thermal efficiency significantly improved with increasing the shell side flow rate and the injected air flow *** maximum improvement in U,NTU,and effectiveness was 153%,153%,and 68%,*** thermal performance of the heat exchanger was sh.wn to b. improved with increasing the b.b.le *** the latter finding agrees with recent CFD pub.ished results,more studies need to b. confirmed.

关键词： Sparger smooth helical coil vertical shell heat exchanger injection b.b.les

Facile hydrothermal synthesis of flower-like hematite microstructure with high photocatalytic properties

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2015年第1期4卷 61-64页

作者： Timur sh.ATAb.EV Department of Physics and Astronomy Seoul National UniversityGwanak-guSeoul 151-747Republic of Korea

A flower-like hematite microstructure has b.en successfully prepared b. a facile hydrothermal synthesis method without using any organic solvents or *** is revealed that the flower-like hematite microstructure consists of well-crystallized nanorods with the average diameter of ab.ut 100±15 nm and average length of ab.ut 900±100 nm growing from the centers.A possib.e growth mechanism of the flower-likeα-Fe_(2)O_(3)microstructure is proposed and *** photocatalytic properties of the synthesized flower-like hematite nanostructure are evaluated using the degradation of rhodamine b.in aqueous solution.

关键词： hematite nanostructure hydrothermal synthesis

Turb.lent Melt Flow Excited b. Amplitude-andFrequency Modulated RMF

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第S1期19卷 483-486页

作者： A.Kapusta M.Khavkin sh.Lesin b.Mikhailovich b.Tilman Center for MHD Studies Ben-Gurion University of the NegevBeer-ShevaIsrael Department of Mechanical Engineering Ben-Gurion University of the NegevBeer-ShevaIsrael Energetics Technologies Ltd OmerIsrael

We examine MHD processes arising in melts placed in vessels of circular and rectangular cross-sections under the action of amplitude-and-frequency modulated rotating magnetic *** is estab.ished that b.sides the mean t... 详细信息

关键词： rotating magnetic field amplitude-and-frequency modulation electromagnetic b.dy force velocity field velocity oscillation external friction model