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Bunching and Antibunching in Cavity QED

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Communications in Theoretical Physics 2011年第7期56卷 134-138页

作者： h.Jabri h.Eleuch Dpartement de Physique Facult des Sciences de Tunis Institute for Quantum Studies Texas A & M UniversityCollege Station Texas University of Carthage

We study the statistics of the emitted filed from Rydberg atom confined inside a microcavity and interacting with a pump laser in the strong coupling regime. We explore the manifestation of the antibunching in connect... 详细信息

关键词： quantum fluctuations quantum noise photon statistics cavity quantum electrodynamics

Plant conservation in the Anthropocene-Challenges and future prospects

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Plant Diversity 2017年第6期39卷 314-330页

作者： Vernon h.heywood School of Biological Sciences University of Reading

Despite the massive efforts that have been made to conserve plant diversity across the world during the past few decades, it is becoming increasingly evident that our current strategies are not sufficiently effective to prevent the continuing decline in biodiversity. As a recent report by the CBD indicates,current progress and commitments are insufficient to achieve the Aichi Biodiversity Targets by *** species lists continue to grow while the world's governments fail to meet biodiversity conservation goals. Clearly, we are failing in our attempts to conserve biodiversity on a sufficient *** reasons for this situation are complex, including scientific, technical, sociological, economic and political factors. The conservation community is divided about how to respond. Some believe that saving all existing biodiversity is still an achievable goal. On the other hand, there are those who believe that we need to accept that biodiversity will inevitably continue to be lost, despite all our conservation actions and that we must focus on what to save, why and where. It has also been suggested that we need a new approach to conservation in the face of the challenges posed by the Anthropocene biosphere which we now inhabit. Whatever view one holds on the above issues, it is dear that we need to review the effectiveness of our current conservation strategies, identify the limiting factors that are preventing the Aichi goals being met and at the same time take whatever steps are necessary to make our conservation protocols more explicit, operational and efficient so as to achieve the maximum conservation effect. This paper addresses the key issues that underlie our failure to meet agreed targets and discusses the necessary changes to our conservation approaches. While we can justifiably be proud of our many achievements and successes in plant conservation in the past 30 years, which have helped slow the rate of loss, unless we devise a more coherent, consisten

关键词： Plant conservation Anthropocene Aichi targets Biodiversity governance Protected areas

Continuous Spectrum of Trigonometric Rosen-Morse and Eckart Potentials from Free Particle Spectrum

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Communications in Theoretical Physics 2011年第6期55卷 965-968页

作者： h.Panahi h.Pouraramt Department of Physics University of GuilanP.O.Box 41335-1914RashtIran

The shape invariant symmetry of the Trigonometric Rosen-Morse and Eckart potentials has been studied through realization of so（3） and so（2, 1） Lie algebras respectively. In this work, by using the free particle eigenfunction, we obtain continuous spectrum of these potentials by means of their shape invariance symmetry in an algebraic method.

关键词： Trigonometric Rosen-Morse and Eckart potentials supersymmetric quantum mechanics shapeinvariant symmetry so(3) so(2 1)

Comparison of Impact Properties for Carbon and Low Alloy Steels

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Journal of Materials Science & Technology 2011年第10期27卷 931-936页

作者： O.h.Ibrahim Metallurgy Dept. Nuclear Research CentreAtomic Energy Authority

The impact properties of hot rolled carbon steel （used for the manufacture of reinforcement steel bars） and the quenched ＆ tempered （Q＆T） low alloy steel （used in the pressure vessel industry） were determined. The microstructure of the hot rolled carbon steel contained ferrite/pearlite phases, while that of the quenched and tempered low alloy steel contained bainite structure. Impact properties were determined for both steels by instrumented impact testing at temperatures between -150 and 200℃. The impact properties comprised total impact energy, ductile to brittle transition temperature, crack initiation and propagation energy, brittleness transition temperature and cleavage fracture stress. The Q＆T low alloy steel displayed much higher resistance to ductile fracture at high test temperatures, while its resistance to brittle fracture at low test temperatures was a little higher than that of the hot rolled carbon steel. The results were discussed in relation to the difference in the chemical composition and microstructure for the two steels.

关键词： Ferritic/pearlitic steel Bainitic steel Impact properties

A STABILITY ThEOREM FOR CONSTRAINED OPTIMAL CONTROL PROBLEMS

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Journal of Computational Mathematics 2004年第5期22卷 633-640页

作者： M.h.Farag DepartmentofMathematicsandComputerScienceFacultyofEducation lbriSultanateofOman

This paper presents the stability of difference approximations of an optimal control problem for a quasilinear parabolic equation with controls in the coefficients, boundary conditions and additional restrictions. The optimal control problem has been convered to one of the optimization problem using a penalty function technique. The difference approximations problem for the considered problem is obtained. The estimations of stability of the solution of difference approximations problem are proved. The stability estimation of the solution of difference approximations problem by the controls is obtained.

关键词： Finite difference method Penalty function methods Quasilinear Parabolic equations Stability estimations

Solvability of a class of PT-symmetric non-hermitian hamiltonians：Bethe ansatz method

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Chinese Physics B 2017年第6期26卷 14-21页

作者： M Baradaran h Panahi Department of Physics University of Guilan Rasht 41635-1914Iran

We use the Bethe ansatz method to investigate the Schrdinger equation for a class of PT-symmetric non-hermitian hamiltonians. Elementary exact solutions for the eigenvalues and the corresponding wave functions are obtained in terms of the roots of a set of algebraic equations. Also, it is shown that the problems possess sl（2） hidden symmetry and then the exact solutions of the problems are obtained by employing the representation theory of sl（2） Lie algebra. It is found that the results of the two methods are the same.

关键词： PT-symmetry Bethe ansatz method Lie algebraic approach quasi-exactly solvable

Piezoelectric polarization and quantum size effects on the vertical transport in AlGaN/GaN resonant tunneling diodes

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Chinese Physics B 2016年第6期25卷 483-488页

作者： Dakhlaoui h Almansour S Department of Physics College of Science for GirlsUniversity of Dammam (UOD)

In this work,the electronic properties of resonant tunneling diodes（RTDs） based on GaN-AlxGa（1-x）N double barriers are investigated by using the non-equilibrium Green functions formalism（NEG）.These materials each present a wide conduction band discontinuity and a strong internal piezoelectric field,which greatly affect the electronic transport *** electronic density,the transmission coefficient,and the current–voltage characteristics are computed with considering the spontaneous and piezoelectric *** influence of the quantum size on the transmission coefficient is analyzed by varying GaN quantum well thickness,AlxGa1-xN width,and the aluminum concentration *** results show that the transmission coefficient more strongly depends on the thickness of the quantum well than the barrier;it exhibits a series of resonant peaks and valleys as the quantum well width *** addition,it is found that the negative differential resistance（NDR） in the current–voltage（I–V） characteristic strongly depends on aluminum concentration *** is shown that the peak-to-valley ratio（PVR） increases with xAlvalue *** findings open the door for developing vertical transport nitrides-based ISB devices such as Thz lasers and detectors.

关键词： nitride semiconductor resonant tunneling diode current density

ThE FINITE ELEMENT METhOD FOR SEMILINEARPARABOLIC EQUATIONS WITh DISCONTINUOUSCOEFFICIENTS

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Journal of Computational Mathematics 1999年第2期17卷 191-198页

作者： Feng, h Shen, LJ Shenzhen Univ Normal Coll Shenzhen 518060 Peoples R China Inst Appl Phys & Computat Math Lab Computat Phys Beijing 100088 Peoples R China

In this paper we investigate the existence, uniqueness and regularity of the solution of semilinear parabolic equations with coefficients that are discontinuous across the interface, some prior estimates are obtained. A net shape of the finite elements around the singular points was designed in [7] to solve the linear elliptic problems, by means of that net, we prove that the approximate solution has the same convergence rate as that without singularity.

关键词： finite element semilinear parabolic equation discontinuous coefficients

AN OUTLINE OF ThE VARIETIES OF ThE SECOND-ORDER SYSTEMS SCIENCES

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Journal of Systems Science and Systems Engineering 2017年第3期26卷 383-412页

作者： Karl h. Muller International Academy for Systems Science and Cybernetics Steinbeis Transfer Center New Cybernetics Vienna Austria

The systems sciences are based on a universal language of systems which can be used within most academic disciplines in their endeavors for exploring the world. Currently, systems sciences cover a wide variety of different approaches like complex adaptive systems, resilient systems or systems engineering. One of the future extensions of the systems sciences comes through the applications of second-order systems science as a new field of reflexive studies on first-order systems science. This article provides a general background on the relations of first-order science and second-order science in general and then goes on to sketch a basic outline for the second-order systems sciences and their potentials for quality control and for innovations for the first-order systems sciences.

关键词： Optimization