检索结果-南通市图书馆

Journal of Computer science & Technology 2013年第2期28卷 322-328页

作者： Mathu soothana s.Kumar Retna swami Muneeswaran Karuppiah Department of Information Technology Noorul Islam University Department of Computer science and Engineering Mepco Schlenk Engineering College

An innovative and uniform framework based on a combination of Gabor wavelets with principal component analysis （PCA） and multiple discriminant analysis （MDA） is presented in this paper. In this framework, features are extracted from the optimal random image components using greedy approach. These feature vectors are then projected to subspaces for dimensionality reduction which is used for solving linear problems. The design of Gabor filters, PCA and MDA are crucial processes used for facial feature extraction. The FERET, ORL and YALE face databases are used to generate the results. Experiments show that optimal random image component selection （ORICs） plus MDA outperforms ORICs and subspace projection approach such as ORICs plus PCA. Our method achieves 96.25%, 99.44% and 100% recognition accuracy on the FERET, ORL and YALE databases for 30% training respectively. This is a considerably improved performance compared with other standard methodologies described in the literature.

关键词： face recognition multiple discriminant analysis optimal random image component selection principal com- ponent analysis recognition accuracy

seismic retrofitting of reinforced concrete frame structures using GFRP-tube-confined-concrete composite braces

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2012年第1期11卷 91-105页

作者： Nasim s. Moghaddasi B Zhang Yunfeng Hu Xiaobin Department of Civil and Environmental Engineering University of Maryland College Park MD 20742 USA school of Civil and Architecture Engineering Wuhan University Wuhan 430072 China

This paper presents a new type of structural bracing intended for seismic retrofitting use in framed structures. This special composite brace, termed glass-fiber-reinforced-polymer （GFRP）-tube-confined-concrete composite brace, is comprised of concrete confined by a GFRP tube and an inner steel core for energy dissipation. Together with a contribution from the GFRP-tube confined concrete, the composite brace shows a substantially increased stiffness to control story drift, which is often a preferred feature in seismic retrofitting. An analysis model is established and implemented in a general finite element analysis program - Opensees, for simulating the load-displacement behavior of the composite brace. Using this model, a parametric study of the hysteretic behavior （energy dissipation, stiffness, ductility and strength） of the composite brace was conducted under static cyclic loading and it was found that the area ratio of steel core to concrete has the greatest influence among all the parameters considered. To demonstrate the application of the composite brace in seismic retrofitting, a three-story nonductile reinforced concrete （RC） frame structure was retrofitted with the composite braces. Pushover analysis and nonlinear time-history analyses of the retrofitted RC frame structure was performed by employing a suite of 20 strong ground motion earthquake records. The analysis results show that the composite braces can effectively reduce the peak seismic responses of the RC frame structure without significantly increasing the base shear demand.

关键词： brace composite confined concrete glass-fiber-reinforced polymer frame nonlinear analysis retrofit seismic

Numerical estimation of bank-propeller-hull interaction effect on ship manoeu-vring using CFD method

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2017年第1期29卷 154-167页

作者： s.Kaidi H.smaoui P.sergent CEREMA-DtecEMF 60280 Margny-les-CompiegneFrance sorbonne universites Universite de technologie de Compiegnelaboratoire Roberval60203 Compiegne cedexFrance

This paper presents a numerical investigation of ship manoeuvring under the combined effect of bank and propeller. The incompressible turbulent flow with free surface around the self-propelled hull form is simulated using a commercial CFD software （ANsYs-FLUENT）. In order to estimate the influence of the bank-propeller effect on the hydrodynamic forces acting on the ship, volume forces representing the propeller are added to Navier-stokes equations. The numerical simulations are carried out using the equivalent of experiment conditions. The validation of the CFD model is performed by comparing the numerical results to the availa- ble experimental data. For this investigation, the impact of ship-Bank distance and ship speed on the bank effect are tested with and without propeller. An additional parameter concerning the advance ratio of the propeller is also tested.

关键词： Viscous fluid flow simulation (CFD) bank effect bank-propeller-hull interaction hydrodynamic forces estimations,advance ratio

A crystal plasticity based approach to establish role of grain size and crystallographic texture in the Tension–Compression yield asymmetry and strain hardening behavior of a Magnesium–silver–Rare Earth alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第9期10卷 2546-2562页

作者： sourav Mishra F.Khan s.K.Panigrahi Department of Mechanical Engineering Indian Institute of Technology MadrasChennai 600036Tamil NaduIndia Applied Magnesium Research Group Centre for Materials and Manufacturing for Futuristic MobilityIndian Institute of Technology MadrasChennai 600036Tamil NaduIndia school of Mechanical Engineering Vellore Institute of TechnologyVellore 632014Tamil NaduIndia

Existence of tension–compression yield asymmetry is a serious limitation to the load bearing capablities of Magnesium alloys in a number of light weight structural *** present work is aimed at nullifying the tension to compression asymmetry problem and strain hardening anomalies in a Magnesium–silver–Rare Earth alloy by engineering different levels of microstructural conditions via friction stir processing and post process *** existence and extent of yield asymmetry ratio in the range of microstructural conditions was experimentally obtained through quasistatic tensile and compression *** yield asymmetry problem was profoundly present in specimens of coarse grained microstructures when compared to their fine grained and ultra fine grained *** impact of the microstructure and associated mechanisms of plasticity on the macroscopic strain hardening behavior was established by Kock–Mecking’s *** plasticity simulations using Viscoplastic self Consistency approach revealed the consequential role of extension twinning mechanism for the existence of yield asymmetry and anomalies in strain hardening *** was especially dominant with coarsening of grain *** Microscopy and characterization were conducted thoroughly in partially deformed specimens to confirm the predictions of the above *** role of crystallographic texture for inducing the polarity to Tension–Compression yield asymmetry was corroborated.A critical grain size in Magnesium–silver–Rare earth alloy was hereby established which could nullify influences of extension twinning in yield asymmetry ratio.

关键词： Magnesium silver rare earth alloy Friction stir processing Ultrafine-grained microstructure Tension to compression yield strength asymmetry Crystallographic texture strain hardening Kock mecking plots Visco plastic self consistency

seismic passive earth resistance using modified pseudo-dynamic method

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2017年第2期16卷 263-274页

作者： Anindya Pain Deepankar Choudhury s. K. Bhattacharyya Academy of scientific and Innovative Research(AcsIR) New Delhi 110001IndiaCSIR-Central Building Research InstituteRoorkee 247667India Dept.of Civil Engineering lndian Institute of Technology BombayPowaL Mumbai 400076lndiaAcademy of Scientific and Innovative Research(AcSIR)New Delhi 110001India Dept.of Civil Engineering Indian Institute of Technology KharagpurWest Bengal721302IndiaCSIR-Central Building Research InstituteRoorkee 247667India

In earthquake prone areas, understanding of the seismic passive earth resistance is very important for the design of different geotechnical earth retaining structures. In this study, the limit equilibrium method is used for estimation of critical seismic passive earth resistance for an inclined wall supporting horizontal cohesionless backfill. A composite failure surface is considered in the present analysis. seismic forces are computed assuming the backfill soil as a viscoelastic material overlying a rigid stratum and the rigid stratum is subjected to a harmonic shaking. The present method satisfies the boundary conditions. The amplification of acceleration depends on the properties of the backfill soil and on the characteristics of the input motion. The acceleration distribution along the depth of the backfill is found to be nonlinear in nature. The present study shows that the horizontal and vertical acceleration distribution in the backfill soil is not always in-phase for the critical value of the seismic passive earth pressure coefficient. The effect of different parameters on the seismic passive earth pressure is studied in detail. A comparison of the present method with other theories is also presented, which shows the merits of the present study.

关键词： retaining wall earthquake limit equilibrium method modified pseudo-dynamic method passive earthpressure composite failure mechanism

Temperature-dependent aggregation of bio-surfactants in aqueous solutions of galactose and lactose:Volumetric and viscometric approach

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5期26卷 1119-1131页

作者： s.Chauhan Vivek sharma Maninder Kaur Poonam Chaudhary Department of chemistry Himachal Pradesh University

Modulation in the aggregation behavior of bio-surfactants （bile salts）, sodium cholate （NaC） and sodium deoxycholate （NaDC） in aqueous solutions of carbohydrates （galactose and lactose） have been investigated by measuring the density （ρ）, speed of sound （u） and viscosity （η） of the mixtures at different temperatures 293.15, 298.15, 303.15, 308.15 and 313.15 K. The density and speed of sound data have been used to calculate various volumetric and compressibility parameters such as apparent molar volume （Vφ）, isentropic compressibil- ity （κs）, apparent molar adiabatic compression （κs,φ） to get a better insight into the micellization mechanism of bile salts. Further, the viscosity data have been studied in the light of relative viscosity （ηr） and viscous relaxation time （τ）. some derived parameters such as free volume （νf）, internal pressure （πi） and molar cohesive energy （MCE） of NaC and NaDC in aqueous solution of saccharides have also been calculated from viscosity data in con- junction with density and speed of sound values. All the calculated and derived parameters provide qualitative information regarding the nature of interactions i.e. solute-solute, solute-solvent and solvent-solvent in the solution.

关键词： Density speed of sound Apparent molar volumelsentropic compressibility Viscosity Relative viscosity

Influences of Pr and Ta doping concentration on the characteristic features of FTO thin film deposited by spray pyrolysis

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第10期24卷 414-422页

作者： Güven Turgut Adem Koqyigit Erdal snmez Erzurum Technical University Science FacultyDepartment of Basic Sciences Igdir University Engineering FacultyDepartment of Electrical Electronic Engineering Ataturk University Kazim Karabekir Education FacultyDepartment of Physics

The Pr and Ta separately doped FTO（10 at.% F incorporated sn O2） films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO（FTO） films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction（XRD） measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has（200） preferential orientation, but this orientation changes to（211） direction with Pr and Ta doping ratio increasing. Atomic force microscopy（AFM） and scanning electron microscopy（sEM） analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible（UV-Vis） spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications.

关键词： Pr-doped FTO Ta-doped FTO spray pyrolysis tin oxide thin films double doping

Exponential synchronization of complex dynamical networks with Markovian jumping parameters using sampled-data and mode-dependent probabilistic time-varying delays

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第2期23卷 49-63页

作者： R.Rakkiyappan N.sakthivel s.Lakshmanan Department of Mathematics Bharathiar University Department of Mathematical sciences College of ScienceUAE University

In this paper, the problem of exponential synchronization of complex dynamical networks with Markovian jumping parameters using sampled-data and Mode-dependent probabilistic time-varying coupling delays is investigated. The sam- pling period is assumed to be time-varying and bounded. The information of probability distribution of the time-varying delay is considered and transformed into parameter matrices of the transferred complex dynamical network model. Based on the condition, the design method of the desired sampled data controller is proposed. By constructing a new Lyapunov functional with triple integral terms, delay-distribution-dependent exponential synchronization criteria are derived in the form of linear matrix inequalities. Finally, two numerical examples are given to illustrate the effectiveness of the proposed methods.

关键词： complex networks exponential synchronization mode-dependent time-varying delays linear ma- trix inequalities sampled-data control

Interpenetrating polymers supported on microporous polypropylene membranes for the transport of chromium ions

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2017年第7期25卷 938-946页

作者： Yesid Tapiero Julio sánchez BernabéL.Rivas Polymer Department Faculty of ChemistryUniversity of ConcepdonCasilla 160-C ConcepcionChile

Modifying polypropylene membranes with interpenetrating polymer networks(IPNs) through the incorporation of poly(glycidyl methacrylate-N-methyl-D-glucamine)(P(GMA-NMG)) was performed by in situ synthesis via radical polymerization. The surface of the polypropylene membrane was activated by hydrophilic grafted polyelectrolyte, and then, pressure injection was used for the impregnation of the reactive solution in the *** types of pore-filled membranes were synthesized, chelating interpenetrating homopolymer networks of P(GMA-NMG), and chelating-ion exchange interpenetrating polymer networks(e.g., P(GMA-NMG)/P(AA),P(GMA-NMG)/P(AMPsA), and P(GMA-NMG)/P(Cl VBTA)). After their synthesis, the modified polypropylene membranes were characterized using techniques such as the electrokinetic potential, sEM, FT-IR, and Donnan dialysis to corroborate the chromium ion transport. The P(GMA-NMG) and complex network membranes exhibited a hydrophilic character with a water-uptake capacity between 20% and 35% and a percentage of modification between 4.0% and 7.0% in comparison with the behavior of the unmodified polypropylene *** chromium ions were efficiently transported from the food chamber at p H 9.0 when the 65.2%MTA1 P(Cl VBTA) homopolymer IPN membrane and 48.5% MTAG P(GMA-NMG)/P(Cl VBTA) IPN membrane were used. similarly, hexavalent chromium ions were removed from the food chamber at pH 3.0 when MTAG(63.30%) and MTA1(35.68%) were used in 1 mol·L^(-1)Na Cl solution as the extraction reagent.

关键词： Polypropylene N-methyI-D-glucamine Ion exchange Donnan dialysis Interpenetrating polymer networks Chromium

Comparisons of electrical and optical properties between graphene and silicene A review

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 299-313页

作者： Wirth-Lima A J silva M G sombra A s B Laboratory of Telecommunications and Materials science and Engineering-www.locem.ufc.br-Fortaleza CearaBrazil Department of Physics Science CenterFederal University of Ceara(U.F C.)-FortalezaCear4Brazil state University of Vale do Acarau SobralCeardBrasil

Two-dimensional （2D） metamaterials are considered to be of enormous relevance to the progress of all exact sciences. since the discovery of graphene, researchers have increasingly investigated in depth the details of electrical/optical proper- ties pertinent to other 2D metamaterials, including those relating to the silicene. In this review are included the details and comparisons of the atomic structures, energy diagram bands, substrates, charge densities, charge mobilities, conductivities, absorptions, electrical permittivities, dispersion relations of the wave vectors, and supported electromagnetic modes related to graphene and silicene. Hence, this review can help readers to acquire, recover or increase the necessary technological basis for the development of more specific studies on graphene and silicene.

关键词： graphene silicene electrical/optical properties