Open Physics Volume 11 Issue 5

Open Physics

Volume 11 Issue 5

Contents
Journal Overview

History of the attempts to measure orbital frame-dragging with artificial satellites

Giacomo Renzetti July 28, 2013

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Abstract

An annotated guide to navigate the intricate history of the attempts to measure the Lense-Thirring orbital precessions with artificial satellites is offered to the reader.

Tachyon-polytropic inflation on the brane

Mohammad Setare, Vahid Kamali July 28, 2013

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Abstract

We consider the tachyon-brane inflationary universe model in the context of a polytropic gas equation of state. In slow-roll approximation, we discuss general conditions of this model. For exponential potential, in high-energy limit the characteristics of the model are presented. By using the seven-year Wilkinson Microwave Anisotropy Probe (WMAP7) observational data, we constrain the cosmological parameters of the model.

Effects of chain decays, radial flow and U A(1) restoration on the low-mass dilepton enhancement in $$\sqrt {s_{NN} } = 200$$ GeV Au+Au reactions

Márton Vargyas, Tamás Csörgő, Róbert Vértesi July 28, 2013

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Abstract

In $$\sqrt {s_{NN} } = 200$$ GeV Au+Au collisions PHENIX reported a significant enhancement in the low-mass region (0.1 < m ee < 0.7 GeV) of the dielectron spectrum, which is still not fully understood. Several theoretical works and an indirect measurement suggest, due to the possible restoration of the U A(1) part of the chiral symmetry in a hot and dense medium, that the mass of the η′ meson may substantially decrease. This work reports on a statistically acceptable description of the PHENIX low-mass dilepton enhancement using a radial flow dominated meson spectra, chain decays of long-lived resonances and an in-medium η′ mass modification.

A novel method for non-destructive Compton scatter imaging based on the genetic algorithm

Saleh Ashrafi, Okhtay Jahanbakhsh, Davood Alizadeh, Behrooz Salehpour July 28, 2013

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Abstract

Compton scattering tomography is widely used in numerous applications such as biomedical imaging, nondestructive industrial testing and environmental survey, etc. This paper proposes the use of the genetic algorithm (GA), which utilizes bio-inspired mathematical models, to construct an image of the insides of a test object via the scattered photons, from a voxel within the object. A NaI(Tl) scintillation detector and a 185 MBq 137Cs gamma ray source were used in the experimental measurements. The obtained results show that the proposed GA based method performs well in constructing images of objects.

Method simplifying calculation of coefficients of fractional parentage for translationally invariant shell-model

Saulius Mickevičius, Darius Germanas, Ramutis Kalinauskas July 28, 2013

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Abstract

A new procedure for large-scale calculations of the coefficients of fractional parentage (CFP) for many-particle systems is presented. The approach is based on a simple enumeration scheme for antisymmetric N particle states, and we suggest an efficient method for constructing the eigenvectors of two-particle transposition operator $$P_{N_1 ,N}$$ in a subspace where N 1 and N 2 = N − N 1 nucleons basis states are already antisymmetrized. The main result of this paper is that according to permutation operators $$P_{N_1 ,N}$$ eigenvalues we can distinguish totally asymmetrical N particle states from the other states with lower degree of asymmetry.

Plastic plasma interaction with plasmas with growing atomic number

Andrzej Kasperczuk, Tadeusz Pisarczyk, Tomasz Chodukowski, Zofia Kalinowska, Sergey Gus’kov, Nikolai Demchenko, Jiri Ullschmied, Eduard Krousky, Miroslav Pfeifer, Jiri Skala, Daniel Klir, Jozef Kravarik, Pavel Kubes, Jakub Cikhardt, Karel Rezac, Pawel Pisarczyk July 28, 2013

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Abstract

This paper describes the investigation of the influence of target material atomic number (Z) on the laser-produced plasma pressure. For this reason, several target materials representing a wide range of atomic numbers (Z = 3.5 - 73), i.e. plastic (CH), Al, Cu, Ag, and Ta, were used. The results presented show that the plasma pressure decreases with growing atomic number but in a limited range of Z only. For higher Z, starting approximately from Z = 47 (Ag), the plasma pressure becomes constant, as confirmed by interferometric measurements and x-ray plasma imaging.

Laser scribing on HOPG for graphene stamp printing on silicon wafer

Jelena Butikova, Boris Polyakov, Lauris Dimitrocenko, Edgars Butanovs, Ivars Tale July 28, 2013

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Abstract

Highly oriented pyrolytic graphite (HOPG) was scribed by pulsed laser beam to produce square patterns. Patterning of HOPG surface facilitates the detachment of graphene layers during contact printing. Direct HOPG-to-substrate and glue-assisted stamp printing of a few-layers graphene was compared. Printed graphene sheets were visualized by optical and scanning electron microscopy. The number of graphene layers was measured by atomic force microscopy. Glue-assisted stamp printing allows printing relatively large graphene sheets (40×40 μm) onto a silicon wafer. The presented method is easier to implement and is more flexible than the majority of existing ways of placing graphene sheets onto a substrate.

The hydrogen atom confined in both Debye screening potential and impenetrable spherical box

Shuai Kang, You-Chang Yang, Juan He, Fei-Qiao Xiong, Ning Xu July 28, 2013

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Abstract

The ground state energy, some low-lying excited state energies and oscillator strengths for a hydrogen atom confined in both a Debye screening potential and finite impenetrable spherical box have been calculated. These have been calculated using a linear variational method based on B-spline basis functions. The results have been compared with those of other authors. The evaluated energies and oscillator strengths with respect to different plasma screening parameters with a certain confinement radii are discussed.

Electromagnetic tunneling through a three-layer asymmetric medium containing epsilon-negative slabs

Chao Yang, Hui Zhao July 28, 2013

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With the transfer-matrix method, conditions of extraordinary electromagnetic resonant tunneling through all combinations of three-layer nonmagnetic (µr = 1) media containing epsilon-negative (ENG) and doublepositive (DPS) slabs were explored. We show that abnormal phenomena can occur in the ENG-DPS-ENG structure, without any restriction on the permittivity of the DPS layer. Changes of transmittance as a function of frequency and incidence angle for a dispersive, lossy model are also calculated, and the results demonstrate the possibility of exhibition this counterintuitive tunneling phenomenon in the DPS-ENG-DPS structure within a wide range of incidence angles.

The analysis of the flow of a micropolar fluid between two orthogonally moving porous disks with counter rotating directions

Yina Sun, Xinhui Si, Liancun Zheng, Yanan Shen, Xinxin Zhang July 28, 2013

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Abstract

The present work investigates the unsteady, imcompressible flow of a micropolar fluid between two orthogonally moving porous coaxial disks. The lower and upper disks are rotating with the same angular speed in counter directions. The flows are driven by the contraction and the rotation of the disks. An extension of the Von Kármán type similarity transformation is proposed and is applied to reduce the governing partial differential equations (PDEs) to a set of non-linear coupled ordinary differential equations (ODEs) in dimensionless form. These differential equations with appropriate boundary conditions are responsible for the flow behavior between large but finite coaxial rotating disks. The analytical solutions are obtained by employing the homotopy analysis method. The effects of some various physical parameters like the expansion ratio, the rotational Reynolds number, the permeability Reynolds number, and micropolar parameters on the velocity fields are observed in graphs and discussed in detail.

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Open Physics is a peer-reviewed, open access, electronic journal devoted to the publication of fundamental research results in all fields of physics. The journal provides the readers with free, instant, and permanent access to all content worldwide; and the authors with extensive promotion of published articles, long-time preservation, language-correction services, no space constraints and immediate publication.
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The journal publishes research and review articles, rapid and short communications, comments and replies that cover the following areas of physical sciences:

Acoustics
Astrophysics,
Atomic and Molecular Physics,
Biological and Medical Physics,
Complex Networks, Socio- and Econophysics,
Computational Physics,
Condensed Matter Physics,
Cosmology and Gravitation,
Fluid Mechanics,
Geophysics,
Nanophysics,
Optics and Lasers,
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Statistical and Nonlinear Physics,
Surface Physics,
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