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The quantum Hall's effect:A quantum electrodynamic phenomenon

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Chinese Physics B 2012年第12期21卷 444-450页

作者： a.i.arbab Department of Physics Faculty of ScienceUniversity of Khartoum

We have applied Maxwell＇s equations to study the physics of quantum Hall＇s effect. The electromagnetic properties of this system are obtained. The Hall＇s voltage, VH ---- 27rh2ns/em, where ns is the electron number density, for a 2- dimensional system, and h ---- 27rh is the Planck＇s constant, is found to coincide with the voltage drop across the quantum capacitor. Consideration of the cyclotronic motion of electrons is found to give rise to Hall＇s resistance. Ohmic resistances in the horizontal and vertical directions have been found to exist before equilibrium state is reached. At a fundamental level, the Hall＇s effect is found to be equivalent to a resonant LCR circuit with LH = 2π m/e2ns and CH -= me2/π2h2ns satisfying the resonance condition with resonant frequency equal to the inverse of the scattering （relaxation） time, τs. The Hall＇s resistance is found to be RH = √LH/CH The Hall＇s resistance may be connected with the impedance that the electron wave experiences when it propagates in the 2-dimensional gas.

关键词： quantum Hall effect Maxwell equations electromagnetism

Transport Properties of the Universal Quantum Equation

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Chinese Physics Letters 2012年第3期29卷 21-24页

作者： a.i.arbab Department of Physics Faculty of ScienceUniversity of KhartoumPO Box 321Khartoum 11115Sudan

The universal quantum equation(UQE)is found to describe the transport properties of the quantum *** equation describes a wave equation interacting with constant scalar and vector potentials propagating in spacetime.A new transformation that sends the Schr(o)dinger equation with a potential energy V=-1/2mc^(2)to Dirac's equation is *** Cattaneo telegraph equation as well as a one-dimensional UQE are compatible with our recently proposed generalized continuity ***,a new wave equation resulted from the invariance of the UQE under the post-Galilean transformations is *** equation is found to govern a Klein Gordon's particle interacting with a photon-like vector field(ether)whose magnitude is proportional to the particle's mass.

关键词： particles equation quantum

Phantom Energy with Variable G and A

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Chinese Physics Letters 2008年第12期25卷 4497-4500页

作者： arbab i. arbab Department of Physics Faculty of Science University of Khartoum P.O. Box 321 Khartoum 11115 Sudan 2.Department of Physics and Applied Mathematics Faculty of Applied Sciences and Computer Omdurman Ahlia University P.O. Box 786 Omdurman Sudan

We investigate a cosmological model of a phantom energy with a variable cosmological constant （∧） depending on the energy density （ρ） as ∧∝ρ^α,α=const and a variable gravitational constant G. The model requires α 〈 0 and a negative gravitational constant. The cosmological constant evolves with time as ∧ ∝ t^-2. For ω 〉 - 1 and α 〈 -1 the cosmological constant ∧ 〈 0, G 〉 0 and ρ decrease with cosmic expansion. For ordinary energy （or dark energy）, i.e.ω 〉 -1, we have -1 〈 α〈 0 and β 〉 0 so that G〉0 increases with time and p decreases with time. Cosmic acceleration with dust particles is granted, provided -2/3 〈α〈 0 and ∧〉0.

关键词： field emission molybdenum dioxide enhancement factor

Viscous Dark Energy Models with Variable G and A

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Chinese Physics Letters 2008年第10期25卷 3834-3836页

作者： arbab i. arbab Department of Physics Faculty of Science University of Khartoum PO Box 321 Khartoum 11115 SudanDepartment of Physics and Applied Mathematics Faculty of Applied Sciences and Computer Omdurman Ahlia University PO Box 7S6 Omdurman Sudan

We consider a cosmological model with bulk viscosity η and variable cosmological A ∝p^-α, alpha = const and gravitational G constants. The model exhibits many interesting cosmological features. inflation proceeds du to the presence of bulk viscosity and dark energy without requiring the equation of state p =-p. During the inflationary era the energy density p does not remain constant, as in the de-Sitter type. Moreover, the cosmological and gravitational constants increase exponentially with time, whereas the energy density and viscosity decrease exponentially with time. The rate of mass creation during inflation is found to be very huge suggesting that all matter in the universe is created during inflation.

关键词： the power-law exponents precipitation durative abrupt precipitation change

On the Generalized Continuity Equation

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Chinese Physics Letters 2010年第8期27卷 117-120页

作者： arbab i. arbab Hisham. M. Widatallah Department of Physics Faculty of Science University of Khartoum PO Box 321 Khartoum 11115 Sudan Department of Physics College of Science Sultan Qaboos University PO Box 36 Al-IKhod Muscat 123 Oman

A generalized continuity equation extending the ordinary continuity equation is found using quanternions to show it is compatible with Dirac, Schrǒdinger, Klein-Gordon and diffusion equations. This generalized equation is Lorentz invariant. The transport properties of electrons are found to be governed by the Schr6dinger-like equation and not by the diffusion equation.

关键词： DiFFERENTiAL equations QUATERNiONS DiRAC equation SCHRODiNGER equation KLEiN-Gordon equation ELECTRON transport HEAT equation

A New Wave Equation of the Electron

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Journal of Modern Physics 2011年第9期2卷 1012-1016页

作者： arbab i. arbab 不详

A new form of Dirac equation of a second order partial differential equation is found. With this wave equation the quivering motion (Zitterbewegung) is satisfactorily explained. A quaternionic analogue of Dirac equation is presented and compared with the ordinary Dirac equation. The two equations become the same if we replace the particle rest mass, m0, in the latter by im0. New space and time transformations in which these two equations represent a massless particle are found. The invariance of Klein-Gordon equation under these transformations yields the Dirac equation. The electron is found to be represented by a superposition of two waves with a group velocity equals to speed of light in vacuum.

关键词： Dirac Equation Zitterbewegung Universal Quantum Wave Equation Quaternion Quantum Mechanics

Drude, Hall and Maximal Conductivities: A Unified Complex Model

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Journal of Modern Physics 2012年第9期3卷 1040-1045页

作者： arbab i. arbab Department of Physics Faculty of Science University of Khartoum P.O. Box 321 Khartoum 11115 Sudan

By adopting a complex formulation of Ohm’s law, we arrive at combined equations connecting the conductivities of conductors. The horizontal resistivity is equal to the inverse of Drude’s conductivity δo( ), and the vertical resistivity (ρy) is equal to the Hall’s conductivity ( δH). At high magnetic field, the horizontal conductivity becomes exceedingly small, whereas the vertical conductivity equals to Hall’s conductivity. The Hall’s conductivity is shown to represent the maximal conductivity of conductors. Drude’s and Hall’s conductivities are related by δo =δHωC , where ωC is the cyclotron frequency, and is the relaxation time. The quantization of Hall’s conductivity is attributed to the fact that the magnetic flux enclosed by the conductor is carried by electrons each with h/e, where h is the Planck’s constant and e is the electron’s charge. The Drude’s conductance is found to be equal to Hall's conductance provided the magnetic flux enclosed by the conductor is a multiple of h/e.

关键词： Drude’s Conductivity Hall’s Conductivity Maximal Conductivity Unified Conductivities

Toxicological effects of nanoselenium in animals

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Journal of Animal Science and Biotechnology 2022年第6期13卷 1610-1622页

作者： iqra Bano Sylvie Skalickova Safia arbab Lenka Urbankova Pavel Horky Department of Physiology and Biochemistry Faculty of BioscienceShaheed Benazir Bhutto University of Veterinary&Animal SciencesSakrand 67210Pakistan Department of Animal Nutrition and Forage Production Mendel University in BrnoZemedelska 1CZ-61300 BrnoCzech Republic Key Laboratory of Veterinary Pharmaceutical Development Ministry of AgricultureLanzhou Institute of Husbandry and Pharmaceutical SciencesChinese Academy of Agricultural SciencesLanzhou 730050China.

The productivity and sustainability of livestock production systems are heavily influenced by animal *** maintain homeostatic balance in the body of the animal at different phases of life,the percentage of organically active minerals in livestock feed must be ***(Se)is a crucial trace mineral that is required for the maintenance of many functions of the *** nanoparticles(SeNPs)attracted considerable interest from researchers for a variety of applications a decade ago,owing to their extraordinary *** offer significant advantages over larger-sized materials,by having a comparatively wider surface area,increased surface energy,and high *** its benefits,SeNP also has toxic effects,therefore safety concerns must be taken for a successful *** toxicological effects of SeNPs in animals are characterized by weight loss,and increased mortality rate.A safe-by-strategy to certify animal,human and environmental safety will contribute to an early diagnosis of all risks associated with *** review is aimed at describing the beneficial uses and potential toxicity of SeNPs in various *** will also serve as a summary of different levels of SeNPs which should be added in the feed of animals for better performance.

关键词： Nanoparticles Organism Selenium Toxicity Trace minerals

Construction of a PVC based 15-crown-5 electrochemical sensor for Ag(Ⅰ) cation

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Chinese Chemical Letters 2014年第5期25卷 809-814页

作者： Fereshteh Karimian Gholam Hossein Rounaghi Mohammad Hossein arbab-Zavar Department of Chemistry Faculty of SciencesFerdowsi University of Mashhad

The macrocyclic ligand,15-crown-5,was used as an ionophore for fabrication of a polyvinyl chloride（PVC） based membrane sensor for Ag（Ⅰ） *** construction of the Ag（Ⅰ） cation selective electrode the best response characteristics were obtained using the composition： 15-crown-5/PVC/o-nitrophenyloctylether（NPOE）/sodium tetraphenyl borate（NaTPB） in the percentage ratio of 5.6/30/60.5/3.9（w/w/w/w）.The electrochemical sensor shows a linear dynamic range 1.0 10 7–1.0 10 1mol/L and a Nernstian slope of 58.9 0.5 mV/decade with a detection limit of 8.09 10 8mol/L for Ag（Ⅰ） *** has a fast response time of 〈10 s and can be used for at least 8 weeks without any considerable divergences in its potential *** was successfully used as an indicator electrode in potentiometric titration of Ag（Ⅰ）cation with i and Cl anions and also for the determination of this metal cation in radiology waste water.

关键词： 15-Crown-5 Electrochemical sensor Potentiometry Ag(i)