Solitons for a generalized variable-coefficient nonlinear Schrdinger equation

In this paper,we investigate some exact soliton solutions for a generalized variable-coefficients nonlinear Schrdinger equation (NLS) with an arbitrary time-dependent linear potential which describes the dynamics of soliton solutions in quasi-one-dimensional Bose-Einstein condensations. Under some reasonable assumptions,one-soliton and two-soliton solutions are constructed analytically by the Hirota method. From our results,some previous one-and two-soliton solutions for some NLS-type equations can be recovered by some appropriate selection of the various parameters. Some figures are given to demonstrate some properties of the one-and the two-soliton and the discussion about the integrability property and the Hirota method is given finally.     

Gaseous tracking at linear hadron collider: Pushing the limits

Gaseous detectors have been pushed to the limits when required to operate in the ferocious and aggressive rate environment of the new generation of HEP experiments. A great effort has resulted in the optimization and construction of large systems of gas detectors, some operational and some due for installation. In this paper some examples are presented along with the impediments that have been overcome; some open issues will be highlighted.     

光学系统偏心测量原理及应用

综述了光学系统偏心测试研究方面的发展概况及目前所达到的水平。简要介绍了光学系统偏心测量及基准轴变换原理，并讨论了一些必要的问题。最后介绍了测量方法的一些具体应用，指出了一些测量中应注意的问题和技巧，并介绍了几个具有代表性的，经过多年实践创造出来的应用方法实例。     

非线性热声理论的研究进展

主要总结了热声系统中的非线性热声现象,指出了线性热声理论的不足,回顾了近十年来国内外热声工作者为解释这些非线性现象所做的理论探索,对其发展方向进行了展望.     

Deformed dispersion relations and the Hanbury–Brown–Twiss Effect

In the present work we analyze the possibility of detecting some deformed dispersion relations, emerging in some quantum-gravity models, resorting to the so-called Hanbury–Brown–Twiss effect. It will be proved that in some scenarios the possibilities are not pessimistic. Forsooth, for some values of the corresponding parameters the aforementioned effect could render interesting outcomes.     

On the analogy between the plane and the spherical solutions of einstein equations in the vacuum

It is shown that some simple and interesting analogy between the plane and the spherical solutions of Einstein gravitational equations in vacuum exists. This analogy is applied to the solutions of some problems of motions in the plane gravitational field.The authors thank I. Kraval for performing some calculations.     

Complete spacelike hypersurfaces in orthogonally splitted spacetimes

We provide some “half-space theorems” for spacelike complete non-compact hypersurfaces into orthogonally splitted spacetimes. In particular we generalize some recent work of Rubio and Salamanca on maximal spacelike compact hypersurfaces. Beside compactness, we also relax some of their curvature assumptions and even consider the case of nonconstant mean curvature bounded from above. The analytic tools used in various arguments are based on some forms of the weak maximum principle.     

Modifications on PVC films by ultrasound

PVC films submitted to ultrasonic irradiation presented structural changes as probed by infrared measurements. These measurements showed some infrared bands alterations attributed to the increase concentration of some conformational isomers of PVC and the presence of some new species in the macromolecular matrix.     

酸性条件下染料结晶紫分子的近红外表面增强拉曼散射研究

比较了染料分子结晶紫(CV)在酸性与中性条件下的金胶体系中的近红外表面增强拉曼光谱(NIR-SERS)。结果表明,结晶紫分子-金胶体系中结晶紫分子在1064nm近红外光激发条件下,其荧光得以大大淬灭,同时拉曼得到了至少不低于105倍的增强;当进一步加入硝酸使得其处于酸性气氛下时,由于部分结晶紫分子与硝酸发生了化学作用形成了结晶紫分子的单替代衍生物(HCV),而HCV与结晶紫分子相比,更容易吸附在金属表面,因此结晶紫分子NIR-SERS还将有很大的增强。这可以给我们很大的启示:改变体系的酸碱度也可以达到改变其SERS的增强效果的目的。     

基于受迫振动实验中几个问题的理论推导

本文论述了受迫振动方程建立与求解,相关物理量的理论推导,并附以测量实例进行分析,解决了同学们该实验疑难之处,补充了教材之空缺。     

Absence of screening in certain lattice gauge and plasma models

We discuss some Abelian lattice gauge models of the noncompact variety, including models of relativistic and nonrelativistic plasmas. For all these models we show absence of exponential clustering for some observables in some domains in parameter space. We comment on the physical meaning of these results, in particular with respect to Debye screening of static electric charges.     

Viscous fluid motion around the Kerr-Newman black hole

In some recent papers, it has been shown that electrovac spacetimes may sometimes be interpreted as space-time filled with a viscous fluid—one such spacetime being the Kerr-Newman metric. Here the possible fluid motion in that case is studied in some detail and some interesting features of the motion in the black hole region are pointed out.     

Instanton effects in supersymmetric theories

We calculate some simplest n-point functions in supersymmetric Yang-Mills theories contributed by instantons. The result is not vanishing and we discuss some implications of this. In particular, the dynamics of the supersymmetric theories must exhibit some unusual features.     

Blow-up of Smooth Solutions to the Cauchy Problem for the Viscous Two-Phase Model

In this paper, we will show the blow-up of smooth solutions to the Cauchy problem for the viscous two-phase model in arbitrary dimensions under some restrictions on the initial data. The key of the proof is finding the relations between some physical quantities and establishing some inequalities.     

High energy nuclear collisions: Theory overview

We review some basic concepts of relativistic heavy-ion physics and discuss our understanding of some key results from the experimental program at the relativistic heavy-ion collider (RHIC). We focus in particular on the early time dynamics of nuclear collisions, some result from lattice QCD, hard probes and photons.     

Hamiltonian Feynman-Kac and Feynman Formulae for Dynamics of Particles with Position-Dependent Mass

A Feynman formula is a representation of the semigroup, generated by an initial-boundary value problem for some evolutionary equation, by a limit of integrals over Cartesian powers of some space E, the integrands being some elementary functions. The multiple integrals in Feynman formulae approximate integrals with respect to some measures or pseudomeasures on sets of functions which take values in E and are defined on a real interval. Hence Feynman formulae can be used both to calculate explicitly solutions for such problems, to get some representations for these solutions by integrals over functions taking values in E (such representations are called Feynman-Kac formulae), to get approximations for transition probability of some diffusion processes and transition amplitudes for quantum dynamics and to get computer simulations for some stochastic and quantum dynamics. The Feynman formula is called a Hamiltonian Feynman formula if the space, Cartesian products of which are used, is the phase space of a classical Hamiltonian system; the corresponding Feynman-Kac formula is called a Hamiltonian Feynman-Kac formula. In the latter formula one integrates over functions taking values in the same phase space. In a similar way one can define Lagrangian Feynman formulae and Lagrangian Feynman-Kac formulae substituting the phase space by the configuration space.     

Chiral photonic crystals with an anisotropic defect layer: Oblique incidence

In the present paper we consider some properties of defect modes in chiral photonic crystals with an anisotropic defect layer at oblique light incidence. The problem is solved by Ambartsumian’s layer addition method. We investigated some peculiarities of the discussed system’s reflection spectra of the oblique light incidence for both the minimum and essential influences of the dielectric boundaries. Then we investigated some particulars of the density of photonic states spectra. We also discussed some peculiarities of the light energy distribution in the system. We found out that at large incidence angles two defect modes arise in the two regions of the selective reflection, each in one respectively, meanwhile, none arises in the central region of the complete reflection. Our investigations show that it is possible to rather widely change the emission peak wavelength in the subject system doped with some laser dye, by changing the incidence angle.     

Modeling opinion interactions in a BBS community

This paper is devoted to apply agent based models to real opinion interactions in a bulletin board system (BBS) community. By analyzing a real BBS community, we reveal some empirical features of opinion interactions on the Web. Then, we propose a simple opinion model that bears both general characteristics of traditional opinion models, and some real interacting rules on the Web. The model simulates a group of agents representing Web users participating to a discussion. Simulation results show some dynamical regimes consistent with empirical facts, and offer some possible explanations for the emergence of some real features. Our work implies the possibility of building simple agent based models to simulate computer-mediated interactions on the Web.     

Controlling soliton explosions

We investigate the dynamics of solitons in generalized Klein–Gordon equations in the presence of nonlinear damping and spatiotemporal perturbations. We will present different mechanisms for soliton explosions. We show (both analytically and numerically) that some space-dependent perturbations or nonlinear damping can make the soliton internal mode unstable leading to soliton explosion. We will show that, in some cases, while some conditions are satisfied, the soliton explodes becoming a permanent, extremely complex, spatiotemporal dynamics. We believe these mechanisms can explain some of the phenomena that recently have been reported to occur in excitable media. We present a method for controlling soliton explosions.     

Why does the intrinsic spin Hall effect in a Rashba two-dimensional electron gas disappear in the dc limit?

Based on a self-consistent semiclassical approach, in this Letter we try to contribute to the basic physical understanding of some controversial issues about the intrinsic spin Hall effect in a Rashba two-dimensional electron gas. We show that for a Rashba two-dimensional electron gas in the diffusive transport thermodynamic limit, there exist some simple but much clear physical reasons which explain naturally why the intrinsic spin Hall effect in such a system cannot survive in the dc limit. The physical pictures established in this Letter resolve some puzzles existed in some previous theoretical treatments about this extraordinary effect.