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THE ROLE OF QUENCHED-IN VACANCIES IN THE ORDERING PROCESS OF AuCu ALLOY
淬入空位在AuCu有序化过程中的作用

SHI TIAN-SHENG,
施天生

物理学报 , 1981,
Abstract: The effect of quenching and aging temperature on ordering process of AuCu alloy was investigated.Based on the experimental results obtained, we concluded that1. The ordering process of AuCu alloy can be divided into two stages: 1) formation of short-range order or nucleation with increase in resistivity, followed by 2) long-range ordering with decrease in resistivity.2. The ordering kinetics of AuCu alloy during low temperature aging is mainly limited by migration of the quenched-in vacancies. The rate of ordering process is proportional to the concentration and mobility of quenched-in vacancies.3. The formation energy and migration energy of vacancies in AuCu were estimated to be 0.95 eV and 0.81 eV respectively.4. During isothermal aging, the quenched-in vacancies in AuCu decayed according to the law of second-order reaction.
Energy spectrum and phase diagrams of two-sublattice hard-core boson model  [PDF]
I. V. Stasyuk,O. Vorobyov
Physics , 2013, DOI: 10.5488/CMP.16.23005
Abstract: The energy spectrum, spectral density and phase diagrams have been obtained for two-sublattice hard-core boson model in frames of random phase approximation approach. Reconstruction of boson spectrum at the change of temperature, chemical potential and energy difference between local positions in sublattices is studied. The phase diagrams illustrating the regions of existence of a normal phase which can be close to Mott-insulator (MI) or charge-density (CDW) phases as well as the phase with the Bose-Einstein condensate (SF phase) are built.
Sampling from the thermal quantum Gibbs state and evaluating partition functions with a quantum computer  [PDF]
David Poulin,Pawel Wocjan
Physics , 2009, DOI: 10.1103/PhysRevLett.103.220502
Abstract: We present a quantum algorithm to prepare the thermal Gibbs state of interacting quantum systems. This algorithm sets a universal upper bound D^alpha on the thermalization time of a quantum system, where D is the system's Hilbert space dimension and alpha < 1/2 is proportional to the Helmholtz free energy density of the system. We also derive an algorithm to evaluate the partition function of a quantum system in a time proportional to the system's thermalization time and inversely proportional to the targeted accuracy squared.
Exchange relaxation as the mechanism of ultrafast spin reorientation in two-sublattice ferrimagnets  [PDF]
V. G. Baryakhtar,V. I. Butrim,B. A. Ivanov
Physics , 2013, DOI: 10.1134/S0021364013180057
Abstract: In the exchange approximation, an exact solution is obtained for the sublattice magnetizations evolution in a two-sublattice ferrimagnet. Nonlinear regimes of spin dynamics are found that include both the longitudinal and precessional evolution of the sublattice magnetizations, with the account taken of the exchange relaxation. In particular, those regimes describe the spin switching observed in the GdFeCo alloy under the influence of a femtosecond laser pulse.
Computational study on thermal stability of an AuCu249 alloy cluster on the atomic scale
AuCu249合金团簇热稳定性的原子尺度计算研究

Shao Chen-Wei,Wang Zhen-Hu,Li Yan-Nan,Zhao Qian,Zhang Lin,
邵琛玮
,王振华,李艳男,赵骞,张林

物理学报 , 2011,
Abstract: Structural change of an AuCu intermetallic alloy cluster including 249 atoms during heating is studied by molecular dynamics simulation within the framework of embedded atom method. The analyses of pair-distribution function, atomic density function, and pair analysis technique show that the structural change of this cluster involves different stages from the outer part into the inner part owing to continuously interchanging positions among atoms at elevated temperature. During the change of the atom packing structure, gold atoms move from the inner part to the outer part of this cluster, whereas copper atoms move from the outer part into the inner part.
Sublattice Interference in the Kagome Hubbard Model  [PDF]
Maximilian Kiesel,Ronny Thomale
Physics , 2012, DOI: 10.1103/PhysRevB.86.121105
Abstract: We study the electronic phases of the kagome Hubbard model (KHM) in the weak coupling limit around van Hove filling. Through an analytic renormalization group analysis, we find that there exists a sublattice interference mechanism where the kagome sublattice structure affects the character of the Fermi surface instabilities. It leads to major suppression of Tc for d+id superconductivity in the KHM and causes an anomalous increase of Tc upon addition of longer-range Hubbard interactions. We conjecture that the suppression of conventional Fermi liquid instabilities makes the KHM a prototype candidate for hosting exotic electronic states of matter at intermediate coupling.
Sublattice synchronization of chaotic networks with delayed couplings  [PDF]
Johannes Kestler,Wolfgang Kinzel,Ido Kanter
Physics , 2007, DOI: 10.1103/PhysRevE.76.035202
Abstract: Synchronization of chaotic units coupled by their time delayed variables are investigated analytically. A new type of cooperative behavior is found: sublattice synchronization. Although the units of one sublattice are not directly coupled to each other, they completely synchronize without time delay. The chaotic trajectories of different sublattices are only weakly correlated but not related by generalized synchronization. Nevertheless, the trajectory of one sublattice is predictable from the complete trajectory of the other one. The spectra of Lyapunov exponents are calculated analytically in the limit of infinite delay times, and phase diagrams are derived for different topologies.
Contact process with sublattice symmetry breaking  [PDF]
Marcelo Martins de Oliveira,Ronald Dickman
Physics , 2011,
Abstract: We study a contact process with creation at first- and second-neighbor sites and inhibition at first neighbors, in the form of an annihilation rate that increases with the number of occupied first neighbors. Mean-field theory predicts three phases: inactive (absorbing), active symmetric, and active asymmetric, the latter exhibiting distinct sublattice densities on a bipartite lattice. These phases are separated by continuous transitions; the phase diagram is reentrant. Monte Carlo simulations in two dimensions verify these predictions qualitatively, except for a first-neighbor creation rate of zero. (In the latter case one of the phase transitions is discontinuous.) Our numerical results confirm that the symmetric-asymmetric transition belongs to the Ising universality class, and that the active-absorbing transition belongs to the directed percolation class, as expected from symmetry considerations.
Sublattice imbalance of substitutionally doped nitrogen in graphene  [PDF]
James A. Lawlor,Paul D. Gorman,Stephen R. Power,Claudionor G. Bezerra,Mauro S. Ferreira
Physics , 2014, DOI: 10.1016/j.carbon.2014.05.069
Abstract: Motivated by the recently observed sublattice asymmetry of substitutional nitrogen impurities in CVD grown graphene, we show, in a mathematically transparent manner, that oscillations in the local density of states driven by the presence of substitutional impurities are responsible for breaking the sublattice symmetry. While these oscillations are normally averaged out in the case of randomly dispersed impurities, in graphene they have either the same, or very nearly the same, periodicity as the lattice. As a result, the total interaction energy of randomly distributed impurities embedded in the conduction-electron-filled medium does not vanish and is lowered when their configuration is sublattice-asymmetric. We also identify the presence of a critical concentration of nitrogen above which one should expect the sublattice asymmetry to disappear. This feature is not particular to nitrogen dopants, but should be present in other impurities.
人工神经网络法研究填隙AuCu_3相组成规律
严六明
科学通报 , 1994,
Abstract: 用人工神经网络方法和化学键参数方法相结合,总结无机化合物若干规律,训练后的网络可作为知识表达方式用于化学专家系统.我们用这一方法研究填隙AuCu_3相的化学成分规律,作为建造合金的神经网络专家系统的初步尝试的一部分.填隙AuCu_3相是一大类三元金属间化合物,其通式为TM_3 X_x(0
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