摘要:

Elastic properties of a class of two‐dimensional model systems, consisted of hard cyclic multimers, are discussed. Each multimer is composed ofm= 3k(wherekis a positive integer) hard discs of diameter &sgr; and centers forming a perfect polygon ofm‐sides, where the side length isl. Close packed structures of such systems, which are isotropic from the point of view of elastic properties, were solved exactly in the close packing limit at zero temperature. It was shown that the Poisson ratio,vP, of the multimers is negative when their roughness parameter, defined as &agr; ≡l/(2&sgr;), is large. In the limitm→ ∞ one obtains hard disc‐like particles, which in contrast to the standard hard discs arerough. It is conjectured that the formula obtained for the Poisson ratio of the 3k‐multimers,vP= (1 − 2&agr;2)/(3 − 2&agr;2), is valid also form≠ 3kin the limitm→ ∞. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764282

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We have performed femtosecond time‐resolved fluorescence spectroscopy up to 10 ns for a dye molecule in a alcohol mixture at 170 K and 296 K. It has been found that the energy relaxation occurs in the electronic excited state of the molecule owing to the structural dynamics of the surroundings of the molecule with time constants of the order of 0.1 ps, 1 ps and a slower one, and the temperature dependence of it implies that there is some connection among the relaxation components with different time constants. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764283

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

In this paper we explore the possibilities given by the ac‐susceptibility &khgr;(&ohgr;), to gain information about the dynamical response of a system in the critical region. Sr3Ru2O7is known to be a strongly correlated metal with an itinerant metamagnetic first order transition, that can also be associated with a new type of quantum critical point. We study the &khgr;(&ohgr;) of this system and show that the (tuneable) finite characteristic time associated with the measurement allows us, in addition to determining the experimentalH,Tphase diagram, to get information about the dynamics of this system in the critical region. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764284

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

Deformation of an elastic tube adhering onto a substrate due to van der Waals attractive interaction is investigated by means of computer simulation and scaling theory. The sum of the stretching, bending, and van der Waals energies of the tube is numerically minimized using the conjugate gradient method. The onset of the deformation and the total energy can be scaled with a variableCb/N2, whereCbis the bending constant andNthe size of the tube. For a significantly deformed tube, the scaling relation between the bending energy and the bending constant is explained within the shell theory. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764285

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We consider the coarse graining of the generalized Brazovskii free energy functional for striped patterns. The technique developed by Shankar for the Fermi liquids is combined with the irreducible version of the exact renormalization group to calculate the recursion relations for interaction vertices. We perform the one‐loop calculations from this method taking the eight‐point vertex into account. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764286

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

A method for evaluating the effectively global exploration in the cost space is introduced and the result is used for an adaptive stopping criterion in optimization by local search heuristics. As an example, an adaptive cooling schedule in simulated annealing (SA) is properly designed and its performance is empirically examined on the Euclidean traveling salesman problem. The present adaptive SA outperforms a conventional non‐adaptive one both in quality and in stability. The performance seems to be affected by the total number of search steps and by the final temperature; the parameters used for an conventional standard design of cooling schedule seem to influence the performance indirectly, only through the former two factors. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764287

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We obtain an exact stationary distribution of a noise‐driven modified van der Pol oscillator and discuss thermodynamic behaviors of the system. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764288

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We propose a theory which establishes a consistency between thermodynamics and quantum pure states. In the theory, thermodynamical entropy is defined in terms of parameter that characterizes quantum pure states. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764289

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We investigate the oxygen rearrangement model by using a cluster model of the copper oxide. The potential energy surface is estimated by the semiempirical molecular orbital calculation (AM1). We discuss the jumping of oxygen ions in the Cu‐O chain in relation to the possibility of the laser control of the oxygen ion. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764290

出版商:AIP    

年代:1904

数据来源: AIP

摘要:

We present a theory of proton transfer reactions which incorporate the modulation of the proton’s potential surface by intermolecular vibrations and the effect of coupling to solvent degree of freedom. The proton tunnels between states corresponding to it being localized in the wells of a double minimum potential. The resulting tunnel splitting depends on the intermolecular separation. The solvent response to the proton’s charge is modeled as that of a continuous distribution of harmonic oscillators and the intermolecular stretching mode is also damped because of the interaction with solvent degree of freedom. The transition rate is given by the Fermi Gorlden Rule expression. © 2004 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1764291

出版商:AIP    

年代:1904

数据来源: AIP