检索结果-南通市图书馆

Chinese Physics B 2012年第10期21卷 251-254页

作者： s.saviz E.Lashani Farzin M.Aghamir Plasma Physics Research Center Science and Research BranchIslamic Azad UniversityTehranP.O.Box 14665-678Iran Department of Physics University of TehranN.Kargar AveTehran 14399Iran

A theory for the two-stream free-electron laser（TsFEL） with a helical wiggler and an axial guide magnetic field is *** the analysis,the effects of self-fields are taken into *** analysis of the two-stream steady-state electron trajectories is given by solving the equation of *** calculations show that there are seven groups of orbits in the presence of self-fields instead of two groups reported in the absence of *** stability of the trajectories is studied numerically.

关键词： two-stream free electron laser electron trajectory

Effects of thermophoresis and thermal radiation in mixed convection three-dimensional flow of Jeffrey fluid

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2015年第5期36卷 655-668页

作者： s.A.sHEHZAD T.HAYAT A.ALsAEDI B.AHMAD Department of Mathematics Comsats Institute of Information Technology Department of Mathematics Quaid-i-Azam University Department of Mathematics Faculty of Science King Abdulaziz University

Mixed convection three-dimensional flow of Jeffrey fluid is studied in the presence of thermal radiation and thermophoresis. The relevant problems are formulated,and series solutions are presented for velocities, temperature, and concentration. Convergence of series solutions is obtained graphically and numerically. Effects of different emerging parameters on the velocities, temperature, and concentration fields are plotted and discussed.

关键词： convection formulated Jeffrey Prandtl convergent admissible illustrate relaxation stretching numerically

Lipid enhancement in microalgae by temporal phase separation:Use of indigenous sources of nutrients

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第1期26卷 175-182页

作者： Nidhin sreekumar Ajit Haridas G.s.Godwin N.selvaraju National Institute of Technology(NITC) CalicutIndia National Institute for Interdisciplinary science and Technology(NIIsT) Council of Scientific&Industrial Research(CSIR)ThiruvananthapuramIndia

Microalgae have been recommended as superior candidate for fuel production because of their advantages of higher photosynthetic efficiency, biomass & lipid productivity, and faster growth rate as compared to other energy crops. To meet up all these criteria, we have developed a continuous outdoor micro-algal raceway pond reactor(RPR) and a lab scale indoor tubular photo bioreactor(PBR) for biofuel production. An attempt to utilise indigenous sources of nutrients to improve the economics also revealed that micro-algal culturing can also be used as a mode of nutrient removal and water treatment. The photosynthetic rate and lipid production were enhanced by arresting daytime cell division and promoting night-time cell division. A 50% lipid improvement was observed for the particular algal consortia. Microscopic studies revealed that temporal phase separation could be achieved by adjusting nutrient distribution pattern. To monitor temporal phase separation, it is required to know DNA multiplication model. Quantification of g DNA in RPR confirmed that cell division happens during the night which positively affects the photosynthetic efficiency and lipid productivity of microalgae.

关键词： Temporal phase separation Lipid enhancement Microalgae Biodiesel

Metabolic cost of level,uphill,and downhill running in highly cushioned shoes with carbon-fiber plates

在线全文

学校读者我要写书评

暂无评论

Journal of sport and Health science 2022年第3期11卷 303-308页

作者： Clarissa s.Whiting Wouter Hoogkamer Rodger Kram Locomotion Laboratory Department of Integrative PhysiologyUniversity of ColoradoBoulderCO 80309USA Integrative Locomotion Lab Department of KinesiologyUniversity of MassachusettsAmherstMA 01003USA

Background:Compared to conventional racing shoes,Nike Vaporfly 4% running shoes reduce the metabolic cost of level treadmill running by4%.The reduction is attributed to their lightweight,highly compliant,and resilient midsole foam and a midsole-embedded curved carbon-fiber *** investigated whether these shoes also could reduce the metabolic cost of moderate uphill(+3°) and downhill(-3°) *** tested the null hypothesis that,compared to conventional racing shoes,highly cushioned shoes with carbon-fiber plates would impart the same ~4%metabolic power(W/kg) savings during uphill and downhill running as they do during level ***:After familiarization,16 competitive male runners performed six 5-min trials(2 shoes × 3 grades) in 2 Nike marathon racing-shoe models(streak 6 and Vaporfly 4%) on a level,uphill(+3°),and downhill(-3°) treadmill at 13 km/h(3.61 m/s).We measured submaximal oxygen uptake and carbon dioxide production during Minutes 4-5 and calculated metabolic power(W/kg) for each shoe model and grade ***:Compared to the conventional shoes(streak 6),the metabolic power in the Vaporfly 4% shoes was 3.83%(level),2.82%(uphill),and2.70%(downhill)less(all p s less compared to level running(p=0.04;effect size(Es)=0.561) but was not statistically different between downhill and level running(p=0.17;Es=0.356).Conclusion:On a running course with uphill and downhill sections,the metabolic savings and hence performance enhancement provided by Vaporfly 4% shoes would likely be slightly less overall,compared to the savings on a perfectly level race course.

关键词： Energetics Incline Locomotion Oxygen consumption Running economy

seismic responses of a hemispherical alluvial valley to sV waves: a three-dimensional analytical approximation

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica sinica 2006年第6期22卷 547-557页

作者： Chenggang Zhao Jun Dong Fuping Gao D.-s. Jeng school of Civil Engineering and Architecture Beijing Jiaotong University Beijing 100044 China Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China school of Civil Engineering The University of Sydney Sydney NSW 2006 Australia

Abstract An analytical solution to the three-dimen-sional scattering and diffraction of plane sV-waves by a saturated hemispherical alluvial valley in elastic half-space is obtained by using Fourier-Bessel series expan-sion technique. The hemispherical alluvial valley with saturated soil deposits is simulated with Biot＇s dynamic theory for saturated porous media. The following conclusions based on numerical results can be drawn：（1） there are a significant differences in the seismic response simulation between the previous single-phase models and the present two-phase model; （2） the nor-malized displacements on the free surface of the alluvial valley depend mainly on the incident wave angles, the dimensionless frequency of the incident sV waves and the porosity of sediments; （3） with the increase of the incident angle, the displacement distributions become more complicated; and the displacements on the free surface of the alluvial valley increase as the porosity of sediments increases.

关键词： Biot's dynamic theory saturated porous media Three-dimensional scattering Hemispherical alluvial valley

Mixed H_∞ and Passive Projective synchronization for Fractional Order Memristor-Based Neural Networks with Time-Delay and Parameter Uncertainty

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2017年第10期67卷 483-494页

作者：宋晓娜宋帅 Inés Tejado Balsera 刘磊坡 school of Information Engineering Henan University of Science and Technology Industrial Engineering school University of Extremadura

This paper investigates the mixed Ho~ and passive projective synchronization problem for fractional-order （FO） memristor-based neural networks. Our aim is to design a controller such that, though the unavoidable phenomena of time-delay and parameter uncertainty are fully considered, the resulting closed-loop system is asymptotically stable with a mixed H∞ and passive performance level. By combining active and adaptive control methods, a novel hybrid control strategy is designed, which can guarantee the robust stability of the closed-loop system and also ensure a mixed H∞ and passive performance level. Via the application of FO Lyapunov stability theory, the projective synchronization conditions are addressed in terms of linear matrix inequaiity techniques. Finally, two simulation examples are given to illustrate the effectiveness of the proposed method.

关键词： H∞ and passive performance fractional-order memristor-based neural networks adaptive pro-jective synchronization time delay uncertain parameters

Heat transfer in a porous saturated wavy channel with asymmetric convective boundary conditions

在线全文

学校读者我要写书评

暂无评论

Journal of Central south University 2015年第1期22卷 392-401页

作者： Q.Hussain s.Asghar T.Hayat A.Alsaedi Department of Mathematics COMSATS Institute of Information Technology Department of Mathematics Faculty of Science King Abdulaziz University Department of Mathematics Quaid-I-Azam University 45320

The viscous flow in a wavy channel with convective boundary conditions is investigated. The channel is filled with a porous viscous fluid. Two cases of equal and different external convection coefficients on the walls are taken into account. Effect of viscous dissipation is also considered. The governing equations are derived employing long wavelength and low Reynolds number approximations. Exact closed form solutions are obtained for the simplified equations. Important physical features for peristaltic flow caused by the wavy wave are pumping, trapping and heat transfer rate at the channel walls. These are discussed one by one in depth and detail through graphical illustrations. special attention has been given to the effects of convective boundary conditions. The results show that for Bi1≠Bi2, there exists a critical value of Brinkman number Brc at which the temperatures of both the walls become equal. And, for Bi1>Bi2 and Br>Brc, the temperature of the cold wall exceeds the temperature of hot wall.

关键词： peristalsis heat transfer porous medium convective boundary conditions

POLYMERIC NANOPARTICLEs FROM sUPERCRITICAL CO_2 MICROEMULsION POLYMERIZATION

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer science 2006年第1期24卷 95-101页

作者： Wei-jun Ye Jason s. Keiper Joseph M. Desimone NsF science and Technology Center for Environmentally Responsible solvents and Processes Department of Chemistry University of North Carolina at Chapel Hill CB# 3290 Venable Hall Chapel Hill NC 27599-3290 USA Department of Chemical Engineering North Carolina State University P. O. Box 7905 Raleigh NC 27695-7905 USA

Herein, we reported the microemulsion polymerization in supercritical carbon dioxide. With the aid of an anionic phosphate fluorosurfactant （bis-[2-（F-hexyl）ethyl]phosphate sodium）, water-soluble/CO2-insoluble acryloxyethyltrimethyl ammonium chloride monomer and N,N＇-methylene-bisacrylamide cross-linker were solubilized into CO2 continuous phase via the formation of water-in-CO2 （w/c） microemulsion water pools. Initiated by a CO2-soluble initiator, 2,2＇-azo-bisisobutyronitrile （AIBN）, cross-linked poly（acryloxyethyltrimethyl ammonium chloride） particles were produced and stabilized in these w/c internal water pools. Nano-sized particles with sizes less than 20 nm in diameter and narrow particle size distributions were obtained.

关键词： supercritical carbon dioxide Nanoparticles Microemulsion polymerization.

Carbon Nanoparticles in Nematic Liquid Crystals

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2008年第1期25卷 212-215页

作者： s. Eren san Mustafa Okutan Oguz Koysal Yusuf Yerli Department of Physics Gebze Institute of Technology PO Box 141 Gebze 41400 Kocaeli Turkey

Fullerene C60, C7o, single-walled and multi-walled carbon nanotubes and graphene sheets are doped to nematic liquid crystal （LC） host in the same percentage. Planar samples of these mixtures are prepared and our measurements constitute an optimization basis for possible applications. Fullerene balls are found to be the best compatible material for optical aims and reorientation of LC molecules, while the carbon nanotubes experience some reorientation possibility in LC media and graphene layers are good barriers to preserve reorientation.

关键词： pulsars x-ray spectra relativity and gravitation redshift

Low temperature thermoluminescence behaviour of Y_2O_3 nanoparticles

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 Rare Earths 2019年第1期37卷 19-23,M0002页

作者： s.Delice M.Isik N.M.Gasanly Department of Physics Hitit University Department of Electrical and Electronics Engineering Atilim University Department of Physics Middle East Technical University Virtual International scientific Research Centre Baku State University

Y_2O_3 nanoparticles were investigated using low temperature thermoluminescence (TL) experiments. TL glow curve recorded at constant heating rate of 0.4 K/s exhibits seven peaks around 19, 62, 91,115,162,196 and 215 K. Activation energies and characteristics of traps responsible for observed curves were revealed under the light of results of initial rise analyses and T_(max)-T_(stop) experimental methods. Analyses of TL curves obtained at different stopping temperatures resulted in presence of one quasi-continuously distributed trap with activation energies increasing from 18 to 24 meV and six single trapping centers at49, 117, 315, 409, 651 and 740 meV. Activation energies of all revealed centers were reported in the present paper. structural characterization of Y_2O_3 nanoparticles was accomplished using X-ray diffraction and scanning electron microscopy measurements.

关键词： Y2O3 Luminescence Thermoluminescence Defects Rare earths