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Chinese physics B 2017年第5期26卷 170-176页

作者：巴诺吴向尧李东飞王丹费金有王磊 college of physics Jilin Normal University college of physics Jilin University

A four-level double-ladder cold atoms system with spontaneously generated coherence trapped in a moving optical lattice is explored to achieve optical nonreciprocity. When spontaneously generated coherence（SGC） is present, the remarkable contrast optical nonreciprocity of light transmission and reflection can be generated at each induced photonic bandgap in the optical lattice with a velocity of a few m/s. However, when the SGC effect is absent, the optical nonreciprocity becomes weak or even vanishing due to the strong absorption. It is found that the optical nonreciprocity is related to the asymmetric Doppler effect in transmission and reflection, meanwhile the degree and position of optical nonreciprocity can be tuned by the SGC effect and the Rabi frequency of the trigger field.

关键词： coherence spontaneously ladder trapped resonant dipole transparency vanishing photonic absolute

Effect of hydrostatic pressure and polaronic mass of the binding energy in a spherical quantum dot

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Chinese physics B 2015年第11期24卷 92-97页

作者： A.Rejo Jeice Sr.Gerardin Jayam K.S.Joseph Wilson Department of physics Annai Velankanni College Department of physics Holy Cross College Departmant of physics Arul Anandar College (Autonomous)

Simultaneous effect of hydrostatic pressure and polaronic mass on the binding energies of the ground and excited states of an on-center hydrogenic impurity confined in a GaAs/GaA1As spherical quantum dot are theoretically investigated by the variational method within the effective mass approximation. The binding energy is calculated as a function of dot radius and pressure. Our findings proved that the hydrostatic pressure led to the decrease of confined energy and the increase of donor binding energy. Conduction band non-parabolicity and the polaron masses are effective in the donor binding energy which is significant for narrow dots not in the confined energy. The maximum donor binding energy achieved by the polaronic mass in the ground and excited states are 2%-19% for the narrow dots. The confined and donor binding energies approach zero as the dot size approaches infinity.

关键词： spherical quantum dot square well confinement confined energies effective mass approximation

Physical properties of hexagonal WN_2 under pressure

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Chinese physics B 2011年第9期20卷 163-170页

作者：李晓凤翟红村付宏志刘中利姬广富 college of physics and Electronic Information Luoyang Normal College Laboratory for Shock Wave and Detonation physics Research Institute of Fluid PhysicsChina Academy of Engineering Physics Mathematics college Luoyang Normal College

A first-principles study on the mechanical stability, elastic and thermodynamic properties of WN2 with P63/mmc and P-6m2 phases are reported using the pseudo potential plane wave method within the generalized gradient approx- imation. The calculated equilibrium parameters are in good agreement with the available theoretical data. A complete elastic tensor and crystal anisotropies of the ultra-incompressible WN2 are determined in the wide pressure range. By the elastic stability criteria, it is predicted that P63/mmc and P-6m2 phases in WN2 are not stable above 175.1 GPa and 170.1 GPa, respectively. Finally, by using the quasiharmonic Debye model, the isothermal and adiabatic bulk modulus, and the heat capacity of WN2 are also successfully obtained.

关键词： density functional theory elasticity thermodynamic properties nitrides

First-principles study of mechanical stability and thermal properties of MNNi_3 (M=Zn,Mg,Al) under pressure

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Chinese physics B 2012年第5期21卷 494-500页

作者：翟红村李晓凤杜军毅姬广富 Mathematics college Luoyang Normal College college of physics and Electronic Information Luoyang Normal College Laboratory for Shock Wave and Detonation physics Research Institute of Fluid physics Chinese Academy of Engineering Physics

The mechanical stability,elastic,and thermodynamic properties of the anti-perovskite superconductors MNNi 3（M=Zn,Mg,Al） are investigated by means of the first-principles *** calculated structural parameters and elastic properties of MNNi 3 are in good agreement with the experimental and the other theoretical *** the elastic constants under high pressure,we predict that ZnNNi 3,MgNNi 3,and AlNNi 3 are not stable at the pressures above 61.2 GPa,113.3 GPa,and 122.4 GPa,*** employing the Debye model,the thermodynamic properties,such as the heat capacity and the thermal expansion coefficient,under pressures and at finite temperatures are also obtained successfully.

关键词： density functional theory elasticity thermodynamic properties

Enhanced structural and magnetic properties of microwave sintered Li–Ni–Co ferrites prepared by sol–gel method

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Chinese physics B 2019年第2期28卷 358-362页

作者： NANDeibam Nilima M Maisnam Sumitra Phanjoubam Department of physics Oriental College Department of physics Oriental CollegeTakyel Department of physics Manipur University

The properties of lithium ferrites are very sensitive to chemical composition, synthesis method, and sintering techniques. Li–Ni–Co ferrites with compositional formula Li_(0.45-0.5x)Ni_(0.1)Co_xFe_(2.45-0.5x)O_4, where 0.00 ≤ x ≤ 0.1 in steps of 0.02 were prepared by chemical sol–gel method and sintered by microwave sintering technique. The x-ray diffraction patterns confirmed the formation of single phase with spinel structure in all the samples. The structural parameter *** constant, crystallite size, and x-ray density for these samples were studied and compared with those measured from samples of similar composition prepared by the sol–gel method and sintered by conventional sintering technique. Enhancement in the magnetic properties like Curie temperature, hysteresis parameters was observed by employing sol–gel synthesis combined with microwave sintering. The results obtained and mechanisms involved are discussed in the paper.

关键词： lithium ferrites sol–gel chemistry magnetic properties x-ray diffraction

Relative carrier-envelope phase dependence of resonant propagation of two-colour femtosecond pulses in V-type atomic medium

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Chinese physics B 2010年第6期19卷 349-355页

作者：谭霞王振东王蕾樊锡君 college of physics and Electronics Shandong Normal University college of physics and Electronics Weifang University

Using numerical solution of the full Maxwell-Bloch equations, which is obtained by the finite-difference time-domain method and the iterative predictor-orrector method, we investigate the modulation effect of relative carrierenvelope phase （hereinafter referred to as the relative phase） on resonant propagation of two-colour femtosecond ultrashort laser pulses in a V-type three-level atomic medium. It is found that the pulse splitting occurs for a smaller value of relative phase; when the value of relative phase increases to a certain value, only the variation of pulse shape is present and the pulse splitting does not occur any more; moreover, when the value of relative phase is smaller, the pulse group velocity is larger. The relative phase also has an obvious effect on population and spectral property. Different population transfers can be realized by adjusting the value of relative phase. Generally speaking, for the pulses with smaller areas their spectral strengths and frequency ranges decrease obviously with the value of relative phase increasing; for the pulses with larger areas, with value of the relative phase increasing, their spectral strengths decrease remarkably but the relative strengths of the higher frequency components increase significantly, while the spectral frequency range is not varied evidently.

关键词： two-colour ultrashort pulses relative carrier envelope phase resonant propagation V- type three-level atomic medium

Quantum key distribution series network protocol with M-classical Bobs

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Chinese physics B 2009年第6期18卷 2143-2148页

作者：张现周公伟贵谭勇刚任振忠郭笑天 physics and Information Engineering college Henan Normal University physics and Information Engineering college Luoyang Normal College

Secure key distribution among classical parties is impossible both between two parties and in a network. In this paper, we present a quantum key distribution （QKD） protocol to distribute secure key bits among one quantum party and numerous classical parties who have no quantum capacity. We prove that our protocol is completely robust, i.e., any eavesdropping attack should be detected with nonzero probability. Our calculations show that our protocol may be secure against Eve＇s symmetrically individual attack.

关键词： quantum key distribution symmetrical attack network protocol

Nonlinear resonance phenomenon of one-dimensional Bose Einstein condensate under periodic modulation

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Chinese physics B 2014年第2期23卷 112-116页

作者：花巍刘世兴 college of physics and Technology Shenyang Normal University college of physics Liaoning University

We investigate the effect of an external periodic modulation on the one-dimensional （1D） Bose-Einstein conden- sate with harmonic trapping potential. By numerically solving the Gross-Pitaevskii equation with symplectic algorithm, the nonlinear resonance phenomenon is shown and the corresponding Fourier spectrum is given. The autoresonance phe- nomenon is also presented under almost periodic external modulation, and it shows that the condensate eventually evolves into quasi-periodic oscillation.

关键词： Bose-Einstein condensate resonance periodic modulation symplectic method

Research on the discrete variational method for a Birkhoffian system

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Chinese physics B 2014年第6期23卷 328-332页

作者：刘世兴花巍郭永新 college of physics Liaoning University college of physics and Technology Shenyang Normal University

In this paper, we present a new integration algorithm based on the discrete Pfaff-Birkhoff principle for Birkhoffian systems. It is proved that the new algorithm can preserve the general symplectic geometric structures of Birkhoffian systems. A numerical experiment for a damping oscillator system is conducted. The result shows that the new algorithm can better simulate the energy dissipation than the R-K method, which illustrates that we can numerically solve the dynamical equations by the discrete variational method in a Birkhoffian framework for the systems with a general symplectic structure. Furthermore, it is demonstrated that the results of the numerical experiments are determined not by the constructing methods of Birkhoffian functions but by whether the numerical method can preserve the inherent nature of the dynamical system.

关键词： Birkhoff's equations discrete variational methods general symplectic structure discrete Birkhoff's equations

Effect of p-d exchange with an itinerant carrier in a GaMnAs quantum dot

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Journal of Semiconductors 2013年第7期34卷 1-6页

作者： D.Lalitha A.John Peter Department of physics GTN College Department of physics Government Arts College

Hydrogenic acceptor binding energy as a function of dot radius in a GaMnAs/Ga_（0.6）Al_（0.4）As quantum dot is calculated including the exchange interaction of Mn alloy content with an itinerant *** are performed by varying its dot radius,for various Mn alloy contents in GaMnAs quantum dot within a single band effective mass approximation using variational *** spin polaronic energy of the acceptor impurity for different Mn^（2＋） is evaluated for different dot radii using a mean field theory in the presence of magnetic field *** magnetization is computed in the influence of magnetic field and the Mn *** effective g-factor of the valence band electron with the inclusion of effects of Mn ion impurities is found in the influence of the magnetic *** exchange coupling constant is calculated for various magnetic field *** results show that the p-d exchange interaction in the GaMnAs/Ga_（0.6）Al_（0.4）As quantum dot has a strong dependence on spatial confinement,effect of magnetic field strength and the Mn alloy *** results are in good agreement with the other investigators.

关键词： quantum dot acceptor diluted magnetic semiconductors