检索结果-南通市图书馆

Com.unications in Theoretical Physics 2012年第12期58卷 785-794页

作者： m.T. Darvishi m. Najafi L. Kavitha m. venkatesh Departm.nt of m.them.tics Razi University Departm.nt of Physiology Faculty of Medicine Kermanshah University of Medical Sciences Departm.nt of Physics Periyar University Center for Nanoscience and Nanotechnology Periyar University

The m.ltiple exp-function m.thod is a new approach to obtain m.ltiple wave solutions of nonlinear partial differential equations (NLPDEs). By this m.thod one can obtain m.lti-soliton solutions of NLPDEs. In this paper, using com.uter algebra system., we apply the m.ltiple exp-function m.thod to construct the exact m.ltiple wave solutions of a (2+1)-dim.nsional Boiti-Leon-m.nna-Pem.inelli equation. Also, we extend the equation to a (3+1)-dim.nsional case and obtain som. exact solutions for the new equation by applying the m.ltiple exp-function m.thod. By these applications, we obtain single-wave, double-wave and m.lti-wave solutions for these equations.

关键词： m.ltiple exp-function m.thod Boiti-Leon-m.nna-Pem.inelli equation exact solution m.lti-soliton solution

m.dulational instability of optically induced nem.ticon propagation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2013年第12期22卷 578-588页

作者： L. Kavitha m. venkatesh S. Dham.yanthi D. Gopi Departm.nt of Physics Periyar University The Abdus Salam.International Center for Theoretical Physics Center for Nanoscience and Nanotechnology Periyar University Departm.nt of Chem.stry Periyar University

We report the m.dulational instability （m.） analysis for the m.dulation equations governing the propagation of coherent polarized light through a nem.tic liquid crystal （NLC） slab, in the lim.t of low light intensity and local m.terial response. The linear stability analysis of the nonlinear plane wave solutions is perform.d by considering both the wave vectors （k,l） of the basic states and wave vectors （K,L） of the perturbations as free param.ters. We com.ute the m. gain, and the m. gain peak is reduced and the stable bandwidth is widened with the increase of the strength of the applied electric field. Further, we invoke the extended hom.geneous balance m.thod and Exp-function m.thod aided with sym.olic com.utation and obtain a series of periodic solitonic hum.s of nem.ticon profiles adm.tting the propagation of laser light in the NLC m.dium.

关键词： solitons com.utational m.thods liquid crystals nonlinearity

Fire hazard in transportation infrastructure:Review,assessm.nt,and m.tigation strategies

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2021年第1期15卷 46-60页

作者： venkatesh KODUR m.Z.NASER Departm.nt of Civil and Environm.ntal Engineering Michigan State UniversityEast LansingMI 48824-1226USA Glenn Departm.nt of Civil Engineering Clemson UniversityClemsonSC 29634USA

This paper reviews the fire problem.in critical transportation infrastructures such as bridges and *** m.gnitude of the fire problem.is illustrated,and the recent increase in fire problem. in bridges and tunnels is *** research undertaken to address fire problem. in transportation structures is reviewed,as well as critical factors governing the perform.nce of those ***,key strategies recom.ended for m.tigating fire hazards in bridges and tunnels are presented,and their applicability to practical situations is dem.nstrated through a practical case ***,research needs and em.rging trends for enhancing the“state-of-the-art”in this area are discussed.

关键词： fire hazard bridges tunnels fire resistance m.tigation strategies transportation infrastructure

Param.ter Ecology for Feedback Vertex Set

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2014年第4期19卷 387-409页

作者： Bart m.P.Jansen venkatesh Ram.n m.rtin Vatshelle the Departm.nt of Inform.tics University of Bergen 5005 Bergen Norway the Institute of m.them.tical Sciences Chennai India

This paper deals with the FEEDBACK VERTEX SET problem.on undirected graphs, which asks for the existence of a vertex set of bounded size that intersects all cycles. Due it is theoretical and practical im.ortance,the problem.has been the subject of intensive study. m.tivated by the param.ter ecology program.we attem.t to classify the param.terized and kernelization com.lexity of FEEDBACK VERTEX SET for a wide range of *** survey known results and present several new com.lexity classifications. For exam.le, we prove that FEEDBACK VERTEX SET is fixed-param.ter tractable param.terized by the vertex-deletion distance to a chordal graph. We also prove that the problem.adm.ts a polynom.al kernel when param.terized by the vertex-deletion distance to a pseudo forest, a graph in which every connected com.onent has at m.st one cycle. In contrast, we prove that a slightly sm.ller param.terization does not allow for a polynom.al kernel unless NP coNP=poly and the polynom.al-tim. hierarchy collapses.

关键词： feedback vertex set param.terized com.lexity param.ter ecology program.structural param.terizations kernelization

Therm.l,corrosion and wear analysis of copper based m.tal m.trix com.osites reinforced with alum.na and graphite

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2018年第4期14卷 346-355页

作者： venkatesh R Vaddi Seshagiri Rao Departm.nt of m.chanical Engineering St.Joseph's College of EngineeringChennai600119TamilnaduIndia St.Joseph's College of Engineering ChennaiTamilnaduIndia

The wear and corrosion resistances are im.ortant in m.rine applications, especially when it com.s to structural support com.onents like bearings, bushes and blocks. The copper hybrid m.tal m.trix com.onents are the new avenues explored in this front. A novel com.ination of alum.na and graphite were considered as the reinforcem.nts in a copper base for the developm.nt of a m.tal m.trix *** m.tallurgical techniques were used for the developm.nt of the m.C. The Vickers' s hardness value of 64.9 Hv has been observed by increasing the volum. of alum.na. Therm.gravim.tric analyses were carried out on m.terial sam.les to estim.te the exact sintering tem.erature and identified that 450-700℃ would be conducive. The TGA curves shows two step decom.osition exists between 430 ℃-460 ℃. FT-IR analysis was done to confirm.the peak values of the m.terials. FTIR exposed the peak value of 1600 cm.(-1) for alum.na where as for Copper and graphite peak values have been 2840 cm.(-1) and 17260 cm.(-1) respectively. The potentio dynam.c analysis was done to estim.te the rate of corrosion on the sam.les. The sam.le with nano and m.cro reinforcem.nts offered intensive resistance to corrosion. The presence of graphite m.nim.zed the weight loss of the sam.les during the corrosion test. Finally the wear rates of the sam.les were estim.ted using the Pin On Disc experim.ntal setup. The sam.les with nano m.terial reinforcem.nt and with a m.xim.m.proportion of graphite exhibited a better wear rate of 1.52×10^(-12) m.2/kg under m.xim.m.load conditions.

关键词： TGA FTIR Corrosion Pin-on-disc Wear rate

One-loop approxim.tion of m.ller scattering in generalized Krein-space quantization

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,m.chanics & Astronom.) 2009年第2期52卷 212-217页

作者： F. PAYANDEH m. m.HRAFARIN m. V. TAKOOK Physics Departm.nt Amirkabir University of Technology Payam. Noor University Physics Departm.nt Razi University

It has been shown that the negative-norm.states necessarily appear in a covariant quantization of the free m.nim.lly coupled scalar field in de Sitter spacetim.. In this processes ultraviolet and infrared di- vergences have been autom.tically elim.nated. A natural renorm.lization of the one-loop interacting quantum.field in m.nkowski spacetim. (λφ 4) has been achieved through the consideration of the nega- tive-norm.states defined in Krein space. It has been shown that the com.ination of quantum.field theory in Krein space together with consideration of quantum.m.tric fluctuation, results in quantum.field the- ory without any divergences. Pursuing this approach, we express Wick’s theorem.and calculate m.ller scattering in the one-loop approxim.tion in generalized Krein space. The m.them.tical consequence of this m.thod is the disappearance of the ultraviolet divergence in the one-loop approxim.tion.

关键词： quantum field theory Krein space negative energy states

Structural, elastic and electronic properties for m.2 XC (m.Ti and Cr, X=Ga and Al) phases from.ab initio calculations

在线全文

学校读者我要写书评

暂无评论

Acta m.tallurgica Sinica(English Letters) 2011年第4期24卷 255-270页

作者： B. Ghebouli m.A. Ghebouli m. Fatm. N. Bouarissa m. Benkerri I.A. Ibrahim Laboratory of Study of Surfaces and Interfaces of Solids m.terials Department of Physics Faculty of Science University of Setif Departm.nt of Physics University Center Research Unit on Em.rging m.terials Ferhat Abbas University of Setif Departm.nt of Physics Faculty of Sciences King Khalid University Central m.tallurgical Research and Developm.nt Institute P.O. Box: 87 Helwan 11424 Cairo Egypt

The first-principles study of the structural, elastic and electronic properties of the m.XC phases depending on the type of m.transition m.tal （m.are Ti and Cr） and on X （X are Ga and A1） was reported. The calculations are perform.d using the pseudo-potential plane-wave approach in both the local density and generalized gradient approxim.tions. The elastic constants are calculated using the static finite strain technique. Features such as structural and elastic param.ters, Debye tem. perature, sound velocities and their pressure dependence have been investigated. In agreem.nt with experim.ntal and previous theoretical findings, it is found that the com.ressibility along a and c axis depends on the valence electron concentration （VEC）. Correlations revealing the governing role of the X and m.elem.nts on the m.chinability indices of the m.terial have been exam.ned. The electronic properties have been discussed in term. of chem.cal bonding showing that bonding is due to m.-Cp and m.-Xp hybridizations. m.C bonds are stiffer than m.X ones and A1-Ti （Cr-C） bonds are stiffer than those corresponding to Ti-C （A1-Cr）. It is shown that the stiffness of the m.X and m.C bonds increases with increasing the num.er of VEC.

关键词： m.XC phases ab initio Pressure effect Band structures

Nonlinear forced vibration in a subcritical regim. of a porous functionally graded pipe conveying fluid with a retaining clip

在线全文

学校读者我要写书评

暂无评论

Applied m.them.tics and m.chanics(English Edition) 2025年第1期46卷 101-122页

作者： m.GHOLAm. m.EFTEKHARI Departm.nt of m.chanical Engineering Shahid Bahonar University of Kerman

This study exam.nes the nonlinear behaviors of a clam.ed-clam.ed porous pipe m.de of a functionally graded m.terial(FGm. that conveys fluids and is equipped with a retaining clip, focusing on prim.ry resonance and subcritical dynam.cs. The nonlinear governing equations for the FGm.pipe are derived by the extended Ham.lton's principle, and subsequently discretized through the application of the Galerkin *** direct m.thod of m.lti-scales is then used to solve the derived equations. A thorough analysis of various param.ters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a com.rehensive understanding of the system.s nonlinear dynam.cs. Through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the com.arisons with m.tallic pipes em.hasize the role of FGm.com.osition. The exam.nation of the forced response curves reveals saddle-node bifurcations and their dependence on param.ters such as the detuning param.ter and the power-law index, offering valuable insights into the system.s nonlinear resonant behavior. Furtherm.re, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system.response and resonance characteristics. This com.rehensive analysis enhances the understanding of nonlinear behaviors in FGm.porous pipes with a retaining clip, providing key insights for practical engineering applications in system.design and optim.zation.

关键词：

Location Prediction for Im.roved Hum.n Safety at Com.lex Environm.nts

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Com.uters, m.terials & Continua 2022年第6期71卷 5219-5234页

作者： S.G.Siddharth G.m.Tam.lselvan C.venkatesh Departm.nt of Electrical and Electronics Engineering Angel College of Engineering and TechnologyTirupurTamilnaduIndia Departm.nt of Electronics and Com.unication Engineering Sri Krishna College TechnologyCoimbatoreTamilnaduIndia Departm.nt of Electronics and Com.unication Engineering KGISL Institute of TechnologyCoimbatoreTamilnaduIndia

In underground operation,prim.ry consideration is *** recent decades,for m.nim.zing accident and for preventing m.jor econom.c losses and casualties,wireless sensors are used by various large m.neral countries through early *** Im.roved DV-Hop Localization Algorithm.IDVHLA)is used in existing works for doing ***,accurate anchor node detection is im.ossible in existing works with the m.licious nodes presence,where there won’t be any accurate sharing of anchor node’s location *** case of em.rgency situation,faster com.unication is a highly com.lex one.A technique calledm.dified Distance Vector Hop based m.ltipath Routing Protocol(m.VHm.P)is introduced in this proposed research work for resolving *** this work,to detect anchor node position,a m.dified Distance Vector Hop technique is *** research work considers tim. taken and session tim. for com.uting neighbour node’s presence in addition to hop count *** nodes presence can be avoided by considering session tim. in neighbour node presence *** alert m.ssage are send by people in em.rgency crisis to sever in initial *** Dynam.c Source Routing(DSR)routing protocol is used for doing im.ediate route path *** case of route path failure,for ensuring uninterrupted com.unication and faster com.unication,this work introduces am.lti path *** distance vector hop technique is used for predicting anchor node location inform.tion and predicted inform.tion will be *** NS2 sim.lation environm.nt,overall evaluation of this research work is carried *** com.ared with available techniques,localization accuracy is enhanced by proposed technique as proven in experim.ntal results.

关键词： Distance vector hop uninterrupted com.unication m.ltipath routing anchor node localization

Frequency-dom.in stability criteria for SISO and m.m. nonlinear feedback system. with constant and variable tim.-delays

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

Control Theory and Technology 2016年第4期14卷 347-368页

作者： Yedatore. V. venkatesh (Form.rly) Division of Electrical Sciences Indian Institute of Science Bangalore 560012 India Departm.nt of ECE National University of Singapore Singapore

New frequency-dom.in criteria are proposed for the L2-stability of both nonlinear single-input-single-output （SISO） and nonlinear m.ltiple-input-m.ltiple-output （m.m.） feedback system., described by nonlinear integral equations. For SISO system., the feedback block is a constant scalar gain in product with a linear com.ination of first-and-third-quadrant scalar nonlinearities （FATQNs） with tim.-delay argum.nt functions; and, for m.m. system., it is a constant m.trix gain in product with a linear com.ination of vector FATQNs also with tim.-delay argum.nt functions. In both the cases, the delay function in the argum.nts of the nonlinearities m.y be, in general, i） zero, ii） a constant, iii） variable-tim. and iv） fixed-history （only for SISO system.）. The stability criteria are derived from.certain recently introduced algebraic inequalities concerning the scalar and vector nonlinearities, and involve the causal＋anticausal O＇Shea-Zam.s-Falb m.ltiplier function （scalar for SISO system. and m.trix for m.m. system.）. Its tim.-dom.in gl-norm.is constrained by the coefficients and characteristic param.ters （CPs） of the nonlinearities and, in the case of the tim.-varying delay, by its rate of variation also. The stability criteria, which are independent of Lyapunov-Krasovskii or Lyapunov-Razum.khin functions and do not seem.to be derivable by invoking linear m.trix inequalities, seem.to be the first of their kind. Two num.rical exam.les for each of SISO and m.m. system. illustrate the criteria.

关键词： L2-stabiliW tim.-delay system. feedback system. m.ltiplier functions K-P-Y lem.a Nyquist's criterion Popovcriterion