oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 32 )

2019 ( 426 )

2018 ( 2748 )

2017 ( 2644 )

Custom range...

Search Results: 1 - 10 of 164552 matches for " Li Yan-Min "
All listed articles are free for downloading (OA Articles)
Page 1 /164552
Display every page Item
Lie Symmetries, Perturbation to Symmetries and Adiabatic Invariants of a Generalized Birkhoff System

LI Yan-Min,

中国物理快报 , 2010,
Abstract: We study the perturbation to symmetries and adiabatic invariants of a generalized Birkhoff system. Based on the invariance of differential equations under infinitesimal transformations, Lie symmetries, laws of conservations, perturbation to the symmetries and adiabatic invariants of the generalized Birkhoff system are presented. First, the concepts of Lie symmetries and higher order adiabatic invariants of the generalized Birkhoff system are proposed. Then, the conditions for the existence of the exact invariants and adiabatic invariants are proved, and their forms are given. Finally, an example is presented to illustrate the method and results.
Exact invariants and adiabatic invariants of the singular Lagrange system

Chen Xiang-Wei,Li Yan-Min,

中国物理 B , 2003,
Abstract: Based on the theory of symmetries and conserved quantities of the singular Lagrange system, the perturbations to the symmetries and adiabatic invariants of the singular Lagrange systems are discussed. Firstly, the concept of higher-order adiabatic invariants of the singular Lagrange system is proposed. Then, the conditions for the existence of the exact invariants and adiabatic invariants are proved, and their forms are given. Finally, an example is presented to illustrate these results.
Stability for manifolds of equilibrium states of generalized Birkhoff system

Li Yan-Min,Mei Feng-Xiang,

中国物理 B , 2010,
Abstract: Stability for the manifolds of equilibrium states of a generalized Birkhoff system is studied. A theorem for the stability of the manifolds of equilibrium states of the general autonomous system is used to the generalized Birkhoffian system and two propositions on the stability of the manifolds of equilibrium states of the system are obtained. An example is given to illustrate the application of the results.
Microwave Doppler Spectra of Sea Echoes at High Incidence Angles: Influences of Large-Scale Waves
Yunhua Wang;Yan-Min Zhang;Li-Xin Guo
PIER B , 2013, DOI: 10.2528/PIERB12123004
Abstract: Within the framework of the composite surface scattering model, analytical formulas for Doppler shift and bandwidth of radar echoes backscattered from time-varying sea surface are derived in the forms of three-dimensional integrals. In our derivations, the influences of the tilt modulation (TM), the hydrodynamic modulation (HM), the shadow and the curvature of large-scale undulating waves are all taken into account for achieving more reasonable results. Comparisons between our theoretical curves and the results obtained directly by exact numerical method demonstrate that our formulas can improve the simulated results. On the other hand, the simulations by our formulas can also help to estimate the effects of the TM, the HM, and the shadow of large-scale waves on Doppler behaviors individually. We find that the predicted Doppler shifts are always larger in HH-polarization than in VV-polarization due to the TM. Meanwhile, the simulations also show that the predicted Doppler shifts for both HH- and VV-polarizations would become larger when the HM is considered. In addition, at low-grazing angles (LGA), the shadow effect results in a rapid increase in the predicted Doppler shift, and on the contrary makes the bandwidth narrower.
Holes in a Two-Dimensional Quantum Antiferromagnet
Lu YU,Zhao-bin SU,Yan-min LI
Physics , 1993,
Abstract: A brief review is presented on the studies of the hole motion in a two--dimensional quantum antiferromagnet. An extended introduction is given to cover the background of the problem. The quantum Bogoliubov--de Gennes formalism which treats the local distortion of the spin configuration and the quantum renormalization process on an equal footing, is outlined. The latest development on the central issue, whether a hole can freely propagate on an antiferromagnetic background, is overviewed.
EFFECT OF DIAGONAL DISORDER ON SUPERCONDUCTIVITY IN THE TRIPLET BIPOLARONIC SYSTEM
对角无序对三重态双极化子系统的超导电性的影响

LI YAN-MIN,ZHANG LI-YUAN,
厉彦民
,章立源

物理学报 , 1987,
Abstract: The effect of diagonal disorder on superconductivity of the triplet bipolaronic system with a two-delta random site energy distribution is analysed in the framework of the mean-field approximation. It is found that this kind of disorder strongly affects superconductivity of the system. When the triplet bipolaron concentration is near 1/2, the transition temperature decreased seriously; while when the concentration is small, the normal random site energy can not impede the occurence of superconductivity completely. This results from the tunneling motion of triplet bipolarons. It is therefore expected that superconductivity may appear in some amorphous semiconductors with low bipolaron concentration.
SUPERCONDUCTING A AND B PHASES IN TRIPLET BIPOLARON SYSTEMS
三重态双极化子的超导A相与B相

LI YAN-MIN,ZHANG LI-YUAN,
厉彦民
,章立源

物理学报 , 1986,
Abstract: Superconducting A and B phases in triplet bipolaron system have been treated by useing the selfconsistent broken-symmetry Hartree approximation. The B phase is always more stable than the A phase in the weak coupling case. But in the strong coupling case, owing to the fluctuation feedback effect, the free energy of the A phase can be lower than that of the B phase, or the A-B transition may occur, which is analogous to the superfluid of 3He. The thermody-namic critical field Hc of the stable phase of the system has also been calculated and compared with the upper critical fields of heavy-fermion superconductors, UBe13, UPt3 and URi2Si2. It has been found that Hc can qualitatively account for the abnormal temperature dependences of the upper critical fields of these superconductors.
EFFECT OF DIAGONAL DISORDER ON THE UPPER CRITICAL FIELD OF THE LOCAL ELECTRON PAIR SYSTEM
对角无序对局域电子配对系统的上临界磁场的影响

LI YAN-MIN,ZHANG LI-YUAN,
厉彦民
,章立源

物理学报 , 1988,
Abstract: The effect of diagonal disorder on the upper critical field of the local electron pair system is studied in the framework of the mean field approximation. It is obtained that this kind of disorder greatly changes the temperature behavior of H(c2). Comparing che upper critical field of this system with those of heavy fermion superconductors CeCu2Si2 and UPt3, we find that it could have the similar unusual temperature dependence.
COEXISTENCE OF SUPERCONDUCTIVITY AND FERROMAGNETISM IN THE TRIPLET BIPOLARONIC SYSTEM
三重态双极化子系统的超导与铁磁共存

LI YAN-MIN,ZHANG LI-YUAN,
厉彦民
,章立源

物理学报 , 1987,
Abstract: The problem of coexistence of superconductivity and ferromagnetism in the triplet bipolaro-nic system has been studied by using the symmetry-broken Hartree approximation. It is found that the ground stare of the system is the mixed state of both orders, which is different from the case of usual BCS systems. It is seen from the phase diagram obtained that in the high bipolaro-nic concentration region the system may exhibit a transition from the ferromagnetic to the mixed state on cooling, while in the low concentration region only the transition from the normal to the mixed state is possible.
$B_s^0-\bar B_s^0$ mixing in a family non-universal $Z^{\prime}$ model revisited
Xin-Qiang Li,Yan-Min Li,Gong-Ru Lu,Fang Su
Physics , 2012, DOI: 10.1007/JHEP05(2012)049
Abstract: Motivated by the very recent measurements performed at the LHCb and the Tevatron of the $B_s^0-\bar B_s^0$ mixing, in this paper we revisit it in a family non-universal $Z^{\prime}$ model, to check if a simultaneous explanation for all the mixing observables, especially for the like-sign dimuon charge asymmetry observed by the D0 collaboration, could be made in such a specific model. In the first scenario where the $Z^\prime$ boson contributes only to the off-diagonal element $M_{12}^s$, it is found that, once the combined constraints from $\Delta M_s$, $\phi_s$ and $\Delta \Gamma_s$ are imposed, the model could not explain the measured flavour-specific CP asymmetry $a_{fs}^s$, at least within its $1\sigma$ ranges. In the second scenario where the NP contributes also to the absorptive part $\Gamma_{12}^s$ via tree-level $Z^\prime$-induced $b\to c\bar{c}s$ operators, we find that, with the constraints from $\Delta M_s$, $\phi_s$ and the indirect CP asymmetry in $\bar{B}_d\to J/\psi K_S$ taken into account, the present measured $1\sigma$ experimental ranges for $a_{fs}^s$ could not be reproduced too. Thus, such a specific $Z^\prime$ model with our specific assumptions could not simultaneously reconcile all the present data on $B_s^0-\bar B_s^0$ mixing. Future improved measurements from the LHCb and the proposed superB experiments, especially of the flavour-specific CP asymmetries, are expected to shed light on the issue.
Page 1 /164552
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.