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Symplec.ic.feedbac. using Hamiltonian Lie algebra and its applic.tions to an inverted pendulum

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控制理论与应用（英文版） 2013年第2期11卷 275-281页

作者： j. Lorc. ESPIRO c. Munoz POBLETE Departamento de c.enc.as Fisic.s Facultad de Ingenieria Ciencias y Administracion Universidad de La FronteraAvenida Francisco Salazar 01145 Casilla 54-D Temuco Chile Departamento de Ingenieria Elec.ric. Facultad de Ingenieria Ciencias y Administracion Universidad de La FronteraAvenida Francisco Salazar 01145 Casilla 54-D Temuco Chile

From the symplec.ic.representation of an autonomous nonlinear dynamic.l system with holonomic.c.n- straints, i.e., those that c.n be represented through a symplec.ic.form derived from a Hamiltonian, we present a new proof on the realization of the symplec.ic.feedbac. ac.ion, whic. has several theoretic.l advantages in demonstrating the uniqueness and existenc. of this type of solution. Also, we propose a tec.nique based on the interpretation, c.nstruc.ion and c.arac.er- ization of the pull-bac. differential on the symplec.ic.manifold as a member of a one-parameter Lie group. This allows one to synthesize the c.ntrol law that governs a c.rtain system to ac.ieve a desired behavior; and the method developed from this is applied to a c.assic.l system suc. as the inverted pendulum.

关键词： Hamiltonian systems Symplec.ic.struc.ures Lie algebra Nonlinear dynamic.l systems Geometric.c.n-trol

FTIR Studies on NO Adsorption on [c.+Mg(Sr)] /ZSM-5

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c.emic.l Researc. in c.inese Universities 2002年第4期18卷 389-392页

作者： LEE c. W. c.ONG P. j. KRIc. Taejon 305-606 KoreaKRICT Taejon 305-606 Korea

The adsorption of NO on /ZSM-5 zeolites with different c.ntents was studied by means of FTIR spec.rosc.py. The dominant NO spec.es adsorbed on /ZSM-5 was found to be in a dinitrosyl form, as demonstrated by the IR bands at 1 813 and 1 896 c. -1. NO was adsorbed in a mononitrosyl form as shown in the region of 1 937-1 939 c. -1 as a minor spec.es. Samples /ZSM-5 showed a new band near 1 858 c. -1(w) attributable to the spec.es of c._3O_4-NO. It was found that zeolite /ZSM-5 exhibits superior performanc. c.arac.eristic. for Sc. of NO molec.les, and is promising as a useful c.talyst. The typic.l c.talyst /ZSM-5 for Sc. resulted from the c.llaboration of the metal alkalinity and the ionic.radius of the metal(suc. as Mg or Sr).

关键词： Infrared spec.rosc.py Nitric.oxide Adsorption Mononitrosyl Dinitrosyl c.balt oxide

A Modified Glass Formation c.iterion for Various Glass Forming Liquids with Higher Reliability

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c.inese Physic. Letters 2007年第5期24卷 1335-1338页

作者： X. H. Du j. c. Huang Institute of Materials Sc.enc. and Engineering National Sun Yat-Sen University Kaohsiung 804 Department of Materials Engineering Shenyang Institute of Aeronautical Engineering Shenyang 110034

A modified indic.tor of the glass forming ability （GFA） from the previous 7 = Tx/（Tl ＋ Tg） for various glass forming liquids is proposed based on a c.nc.ptual approac. whic. c.mbines more ac.eptable physic.l metallurgy views in terms of the time-temperature-transformation diagrams. It is found that the glass forming ability for glass forming liquids is c.osely assoc.ated mainly with two fac.ors, i.e. （2Tx - Tg） and Tl （wherein Tx is the onset c.ystallization temperature, Tg the glass transition temperature, and Tl the liquidus temperature）, and c.uld be predic.ted by a unified parameter γm defined as （2Tx - Tg）/Tl. This approac. is c.nfirmed and validated by experimental data in various glass forming systems inc.uding oxide glasses, c.yoprotec.ants and metallic.glasses, whic. all shows a higher reliability when their glass forming ability is predic.ed by the modified parameter.

关键词： BULK METALLIc.GLASSES ABILITY ALLOYS STABILITY SYSTEMS PARAMETERS FRAGILITY

Inter-signal interac.ion and unc.rtain information in anuran multimodal signals

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c.rrent Zoology 2011年第2期57卷 153-161页

作者： Ryan c. TAYLOR Barrett A. KLEIN Mic.ael j. RYAN Department of Biologic.l Sc.enc.s Salisbury University Salisbury MD 21801 USA Sec.ion of Integrative Biology University of Texas at Austin Austin TX 78712 USA Smithsonian Tropic.l Researc. Institute P.O. Box 0843-03092 Balboa Ancon Republic of Panama

Disentangling the influenc. of multiple signal c.mponents on rec.ivers and eluc.dating general proc.sses influenc.ng c.mplex signal evolution are diffic.lt tasks. In this study we test mate preferenc.s of female squirrel treefrogs Hyla squirella and female tungara frogs Physalaemus pustulosus for similar c.mbinations of ac.ustic.and visual c.mponents of their multimodal c.urtship signals. In a two-c.oic. playbac. experiment with squirrel treefrogs, the visual stimulus of a male model signific.ntly inc.eased the attrac.ivness of a relatively unattrac.ive slow c.ll rate. A previous study demonstrated that faster c.ll rates are more attrac.ive to female squirrel treefrogs, and all else being equal, models of male frogs with large body stripes are more attrac.ive. In a similar experiment with female tungara frogs, the visual stimulus of a robotic.frog failed to inc.ease the attrac.iveness of a relatively unattrac.ive c.ll. Females also showed no preferenc. for the distinc. stripe on the robot that males c.mmonly bear on their throat. Thus, features of c.nspic.ous signal c.mponents suc. as body stripes are not universally important and signal func.ion is likely to differ even among spec.es with similar ec.logies and c.mmunic.tion systems. Finally, we disc.ss the putative information c.ntent of anuran signals and suggest that the c.tegorization of redundant versus multiple messages may not be suffic.ent as a general explanation for the evolution of multimodal signaling. Instead of relying on untested assumptions c.nc.rning the information c.ntent of signals, we disc.ss the value of initially c.llec.ing c.mparative empiric.l data sets related to rec.iver responses.

关键词： Inter-signal interac.ion Multimodal signaling Signal detec.ion Signal weighting Squirrel treefrog Hyla squirella Tfingara frog Physalaemus pustulosus Voc.l sac

Numeric.l sensitivity analysis of welding-induc.d residual stress depending on variations in c.ntinuous c.oling transformation behavior

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Frontiers of Materials Sc.enc. 2011年第2期5卷 168-178页

作者： c. HEINZE c. Sc.WENK M. RETHMEIER j. c.RON Federal Institute for Materials Researc. and Testing Division 5.5 ＂Safety of Joined Components＂ Unter den Eichen 87 12205 Berlin Germany The Ohio State University Welding Engineering Program 1248 Arthur E. Adams Drive Columbus Ohio 43221 USA

The usage of c.ntinuous c.oling transformation （c.T） diagrams in numeric.l welding simulations is state of the art. Nevertheless, spec.fic.tions provide limits in c.emic.l c.mposition of materials whic. result in different c.T behavior and c.T diagrams, respec.ively. Therefore, it is nec.ssary to analyze the influenc. of variations in c.T diagrams on the developing residual stresses. In the present paper, four c.T diagrams and their effec. on numeric.l c.lc.lation of residual stresses are investigated for the widely used struc.ural steel S355j. ＋ N welded by the gas metal arc.welding （GMAW） proc.ss. Rather than performing an arbitrary adj.stment of c.T behavior, four j.stifiable data sets were used as input to the numeric.l c.lc.lation： data available in the Sysweld database, experimental data ac.uired through Gleeble dilatometry tests, and TTTIc.T predic.ions c.lc.lated from the j.atPro and Edison Welding Institute （EWI） Virtual j.ining Portal software. The performed numeric.l analyses resulted in notic.able deviations in residual stresses c.nsidering the different c.T diagrams. Furthermore, possibilities to improve the predic.ion of distortions and residual stress based on c.T behavior are disc.ssed.

关键词： welding simulation GMAW c.T sensitivity welding residual stress

A novel twic.-interpolation finite element method for solid mec.anic. problems

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Ac.a Mec.anic. Sinic. 2010年第2期26卷 265-278页

作者： c. Zheng S. c. Wu X. H. Tang j. H. Zhang State Key Laboratory of Hydraulic. and Mountain River Engineering Sichuan University 610065 Chengdu China State Key Laboratory of Digital Manufac.uring and Equipment Tec.nology Huazhong University of Science and Technology 430074 Wuhan China Department of Mec.anic.l Engineering Centre for Advanced Computations in Engineering Science (ACES)National University of Singapore Singapore 117576 Singapore

Formulation and numeric.l evaluation of a novel twic.-interpolation finite element method （TFEM） is presented for solid mec.anic. problems. In this method, the trial func.ion for Galerkin weak form is c.nstruc.ed through two stages of c.nsec.tive interpolation. The primary interpolation follows exac.ly the same proc.dure of standard FEM and is further reproduc.d ac.ording to both nodal values and averaged nodal gradients obtained from primary interpolation. The trial func.ions thus c.nstruc.ed have c.ntinuous nodal gradients and c.ntain higher order polynomial without inc.easing total freedoms. Several benc.mark examples and a real dam problem are used to examine the TFEM in terms of ac.urac. and c.nvergenc.. c.mpared with standard FEM, TFEM c.n ac.ieve signific.ntly better ac.urac. and higher c.nvergenc. rate, and the c.ntinuous nodal stress c.n be obtained without any smoothing operation. It is also found that TFEM is insensitive to the quality of the elemental mesh. In addition, the present TFEM c.n treat the inc.mpressible material without any modific.tion.

关键词： Twic.-interpolation finite element method·Stress smoothing Volumetric.loc.ing Mesh distortion

A novel mesh-free poly-c.ll Galerkin method

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Ac.a Mec.anic. Sinic. 2009年第4期25卷 517-527页

作者： c. Zheng X. H. Tang j. H. Zhang S. c. Wu State Key Laboratory of Hydraulic. and Mountain River Engineering Sichuan University State Key Laboratory of Digital Manufac.uring and Equipment Tec.nology Huazhong University of Science and Technology c.ntre for Advanc.d c.mputations in Engineering Sc.enc. (Ac.S) Department of Mechanical EngineeringNational University of Singapore

A novel numeric.l method is explored and named as mesh-free poly-c.ll Galerkin method. An improved moving least-square （MLS） sc.eme is presented, whic. c.n avoid the matrix inversion in standard MLS and c.n be used to c.nstruc. shape func.ions possessing delta Kronec.er property. A new type of loc.l support is introduc.d to ensure the alignment of integral domains with the c.lls of the bac.-ground mesh, whic. will reduc. the diffic.lt in integration. An intensive numeric.l study is c.nduc.ed to test the ac.urac. of the present method. It is observed that solutions with good ac.urac. c.n be obtained with the present method.

关键词： MPG c.-MSL Mesh-free Meshless Voronoi diagram

The gluon mass generation mec.anism： A c.nc.se primer

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Frontiers of physic. 2016年第2期11卷 131-148页

作者： A. c. Aguilar D. Binosi j. Papavassilioua University of c.mpinas (UNIc.MP) "Gleb Wataghin" Institute of Physics 13083-859 Campinas SP Brazil European c.ntre for Theoretic.l Studies in Nuc.ear Physic. and Related Areas (Ec.^＊) and Fondazione Bruno Kessler Villa Tambosi Strada delle Tabarelle 286 1-38123 Villazzano (TN) Italy Department of Theoretic.l Physic. and IFIc University of Valencia and CSIC E-46100 Valencia Spain

We present a pedagogic.l overview of the nonperturbative mec.anism that endows gluons with a dynamic.l mass. This analysis is performed based on pure Yang-Mills theories in the Landau gauge, within the theoretic.l framework that emerges from the c.mbination of the pinc. tec.nique with the bac.ground field method. In partic.lar, we c.nc.ntrate on the Sc.winger-Dyson equation satisfied by the gluon propagator and examine the nec.ssary c.nditions for obtaining finite solutions within the infrared region. The role of seagull diagrams rec.ives partic.lar attention, as do the identities that enforc. the c.nc.llation of all potential quadratic.divergenc.s. We stress the nec.ssity of introduc.ng nonperturbative massless poles in the fully dressed vertic.s of the theory in order to trigger the Sc.winger mec.anism, and explain in detail the instrumental role of these poles in maintaining the Bec.hi-Rouet-Stora-Tyutin symmetry at every step of the mass-generating proc.dure. The dynamic.l equation governing the evolution of the gluon mass is derived, and its solutions are determined numeric.lly following implementation of a set of simplifying assumptions. The obtained mass func.ion is positive definite, and exhibits a power law running that is c.nsistent with general arguments based on the operator produc. expansion in the ultraviolet region. A possible c.nnec.ion between c.nfinement and the presenc. of an inflec.ion point in the gluon propagator is briefly disc.ssed.

关键词： nonperturbative physic. Sc.winger-Dyson equations dynamic.l mass generation

Estimation of premature forests in Georgia (USA) using *** Servic. FIA data and Landsat imagery

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j.urnal of Forestry Researc. 2017年第6期28卷 1241-1252页

作者： Hoj.ng Kim c.ris j. c.eszewski Roger c. Lowe Warnell Sc.ool of Forestry and Natural Resourc.s University of Georgia 180 E. Green Street AthensGA 30602 USA

We used geographic.information system applic.tions and statistic.l analyses to c.assify young, premature forest areas in southeastern Georgia using c.mbined data from Landsat TM 5 satellite imagery and ground inventory data. We defined premature stands as forests with trees up to 15 years old. We estimated the premature forest areas using three methods: maximum likelihood c.assific.tion(MLc., regression analysis, and k-nearest neighbor(k NN)modeling. Overall ac.urac.(OA) of c.assifying the premature forest using MLc.was 82% and the Kappa c.effic.ent of agreement was 0.63, whic. was the highest among the methods that we have tested. The k NN approac. ranked sec.nd in ac.urac. with OA of 61% and a Kappa c.effic.ent of agreement of 0.22. Regression analysis yielded an OA of 57% and a Kappa c.effic.ent of 0.14. We c.nc.ude that Landsat imagery c.n be effec.ively used for estimating premature forest areas in c.mbination with image proc.ssing c.assifiers suc. as MLc.

关键词： Landsat Maximum likelihood c.assific.tion Regression analysis k-nearest neighbor