Search results for "Potential"
showing 10 items of 3348 documents
Shape Optimization in Contact Problems. 1. Design of an Elastic Body. 2. Design of an Elastic Perfectly Plastic Body
1986
The optimal shape design of a two dimensional body on a rigid foundation is analyzed. The problem is how to find the boundary part of the body where the unilateral boundary conditions are assumed in such a way that a certain energy integral (total potential energy, for example) will be minimized. It is assumed that the material of the body is elastic. Some remarks will be given concerning the design of an elastic perfectly plastic body. Numerical examples will be given.
A signal processing scheme based on high-frequency electromechanical oscillations in nanostructures
2009
We explore the characteristics of a new signal processing scheme based on the high-frequency electromechanical oscillations of a nanostructure formed by an oscillating metallic nanoparticle connected to the left and right electrodes by soft links. Because this system shows resonant behavior when the frequency of the applied electric potential is close to the characteristic natural frequency of the oscillating nanoparticle, a parallel arrangement of nanostructures with different frequencies can be excited selectively by an external time-dependent electrical signal with the appropriate resonant frequencies. The highly nonlinear system response makes it possible to devise a signal processing s…
Investigations of Superheavy Quasiatoms via Spectroscopy of δ Rays and Positrons
1984
There exists a long-standing and very interesting problem in atomic physics, namely, the question: What is the binding energy of an electron if the strength of the Coulomb potential exceeds Zα = 1? According to the Dirac-Sommerfeld fine-structure formula for a point charge $$E = {m_e}{c^2}{[1 - {(Z\alpha )^2}]^{1/2}}$$ (1) the total energy of the lowest bound Is-state becomes imaginary for Zα > 1. But even as early as 1945 it was realized(59) that this property of Eq. (1) is caused by the singularity of the Coulomb potential at the origin. Assuming a realistic charge distribution of the nucleus there is no restriction suc as Zα < 1 for the binding energy. Recent calculations show (cf., e.g.…
Towards the field theory of the Standard Model on fractional D6-branes on T6 /ℤ6 ′ : Yukawa couplings and masses
2012
We present the perturbative Yukawa couplings of the Standard Model on fractional intersecting D6-branes on T6/Z6' and discuss two mechanisms of creating mass terms for the vector-like particles in the matter spectrum, through perturbative three-point couplings and through continuous D6-brane displacements.
Amorphous silica modeled with truncated and screened Coulomb interactions: A molecular dynamics simulation study
2007
We show that finite-range alternatives to the standard long-range BKS pair potential for silica might be used in molecular dynamics simulations. We study two such models that can be efficiently simulated since no Ewald summation is required. We first consider the Wolf method, where the Coulomb interactions are truncated at a cutoff distance r_c such that the requirement of charge neutrality holds. Various static and dynamic quantities are computed and compared to results from simulations using Ewald summations. We find very good agreement for r_c ~ 10 Angstroms. For lower values of r_c, the long--range structure is affected which is accompanied by a slight acceleration of dynamic properties…
Inherent structure entropy of supercooled liquids
1999
We present a quantitative description of the thermodynamics in a supercooled binary Lennard Jones liquid via the evaluation of the degeneracy of the inherent structures, i.e. of the number of potential energy basins in configuration space. We find that for supercooled states, the contribution of the inherent structures to the free energy of the liquid almost completely decouples from the vibrational contribution. An important byproduct of the presented analysis is the determination of the Kauzmann temperature for the studied system. The resulting quantitative picture of the thermodynamics of the inherent structures offers new suggestions for the description of equilibrium and out-of-equilib…
Enhancement of stability in randomly switching potential with metastable state
2004
The overdamped motion of a Brownian particle in randomly switching piece-wise metastable linear potential shows noise enhanced stability (NES): the noise stabilizes the metastable system and the system remains in this state for a longer time than in the absence of white noise. The mean first passage time (MFPT) has a maximum at a finite value of white noise intensity. The analytical expression of MFPT in terms of the white noise intensity, the parameters of the potential barrier, and of the dichotomous noise is derived. The conditions for the NES phenomenon and the parameter region where the effect can be observed are obtained. The mean first passage time behaviours as a function of the mea…
Thermodynamics of supercooled liquids in the inherent structure formalism: a case study
2000
In this article we review the thermodynamics of liquids in the framework of the inherent structure formalism. We then present calculations of the distribution of the basins in the potential energy of a binary Lennard-Jones mixture as a function of temperature. The comparison between the numerical data and the theoretical formalism allows us to evaluate the degeneracy of the inherent structures in a bulk system and to estimate the energy of the lowest energy disordered state (the Kauzmann energy). We find that, around the mode-coupling temperature, the partition function of the liquid is approximated well by the product of two loosely coupled partition functions, one depending on the inheren…
How to solve Fokker-Planck equation treating mixed eigenvalue spectrum?
2013
An analogy of the Fokker-Planck equation (FPE) with the Schr\"odinger equation allows us to use quantum mechanics technique to find the analytical solution of the FPE in a number of cases. However, previous studies have been limited to the Schr\"odinger potential with a discrete eigenvalue spectrum. Here, we will show how this approach can be also applied to a mixed eigenvalue spectrum with bounded and free states. We solve the FPE with boundaries located at x=\pm L/2 and take the limit L\rightarrow\infty, considering the examples with constant Schr\"{o}dinger potential and with P\"{o}schl-Teller potential. An oversimplified approach was proposed earlier by M.T. Araujo and E. Drigo Filho. A…
Acceleration of diffusion in randomly switching potential with supersymmetry
2004
We investigate the overdamped Brownian motion in a supersymmetric periodic potential switched by Markovian dichotomous noise between two configurations. The two configurations differ from each other by a shift of one-half period. The calculation of the effective diffusion coefficient is reduced to the mean first passage time problem. We derive general equations to calculate the effective diffusion coefficient of Brownian particles moving in arbitrary supersymmetric potential. For the sawtooth potential, we obtain the exact expression for the effective diffusion coefficient, which is valid for the arbitrary mean rate of potential switchings and arbitrary intensity of white Gaussian noise. We…