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Efficiently enhanced energy storage performance of Ba_(2)Bi_(4)Ti_(5)O_(18) film by co-doping Fe^(3+)and Ta^(5+)ion with larger radius

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Chinese Physics B 2022年第9期31卷 540-546页

作者： Qiong Wu Lei Zhao Xinghao Chen Shifeng Zhao Inner Mongolia Key Laboratory of Nanoscience and Nanotechnology &School of Physical Science and TechnologyInner Mongolia UniversityHohhot 010021China

We present an efficient strategy,that is the co-substitution of Fe^(3+)and Ta^(5+)ions with large radius for Ti^(4+)ion,to enhance energy storage performance of Ba_(2)Bi_(4)Ti_(5)O_(18) *** the films co-doped with Fe^(3+)and Ta^(5+)ions,the maximum polarization under the same external electric field is improved because the radius of Fe^(3+)and Ta^(5+)ions is larger than that of Ti^(4+)***,due to the composition and chemical disorder,the relaxor properties are also slightly improved,which can not be achieved by the film doped with Fe^(3+)ions *** is more,for the films doped with Fe^(3+)ion only,the leakage current density increases greatly due to the charge imbalance,resulting in a significant decrease in breakdown *** is worth mentioning that the breakdown strength of Fe^(3+)and Ta^(5+)ions co-doped film does not decrease due to the charge *** important point is the recoverable energy storage density of the films co-doped with Fe^(3+)and Ta^(5+)ions has been greatly improved based on the fact that the maximum external electric field does not decrease and the maximum polarization under the same external electric field *** top of that,the hysteresis of the polarization has also been ***,the co-doped films with Fe^(3+)and Ta^(5+)ions have good frequency and temperature stability.

关键词： Ba_(2)Bi_(4)Ti_(5)O_(18)film ferroelectrics energy storage co-doped radius

Jet radius and Momentum Splitting Fraction with Dynamical Grooming in Heavy-Ion Collisions

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Chinese Physics Letters 2023年第3期40卷 1-6页

作者：王磊康锦文张清申淑婉代巍张本威王恩科 Key Laboratory of Quark and Lepton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan 430079China School of Mathematics and Physics China University of Geosciences(Wuhan)Wuhan 430074China Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum MatterSouth China Normal UniversityGuangzhou 510006China

We investigate the medium modifications of momentum splitting fraction and groomed jet radius with both dynamical grooming and soft drop algorithms in heavy-ion *** the calculation,the partonic spectrum of initial hard scattering in p+p collisions is provided by the event generator PYTHIA8,and the energy loss of fast parton traversing in a hot/dense quantum-chromodynamic medium is simulated with the linear Boltzmann transport *** predict the normalized distributions of the groomed jet radiusθ_(g)and momentum splitting fraction z_(g)with the dynamical grooming algorithm in Pb+Pb collisions at(sNN)~(1/2)=5.02 TeV,then compare these quantities in dynamical grooming at a=0.1,with that in soft drop at z_(out)=0.1 andβ=*** is found that the normalized distribution ratios Pb+Pb/p+p with respect to z_(g)in z_(cut)=0.1,β=0 soft drop case are close to unity,those in a=0.1 dynamical grooming case show enhancement at small z_(g),and Pb+Pb/p+p with respect toθ_(g)in the dynamical grooming case demonstrate weaker modification than those in the soft drop *** further calculate the groomed jet number averaged momentum splitting fraction_(jets)and averaged groomed jet radius_(jets)in p+p and A+A for both grooming cases in three p_T~(ch jet)intervals,and find that the originally generated well balanced groomed jets will become more momentum imbalanced and jet size less narrowed due to jet quenching,and weaker medium modification of z_(g)andθ_(g)in the a=0.1 dynamical grooming case than in the soft drop counterparts.

关键词： momentum dynamical radius

Dipole AlfvenVortex with Finite Ion Larmor radius in a Low-Beta Plasma

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Chinese Physics Letters 2000年第7期17卷 517-518页

作者： WANG Xu-Yu HE Xian-Tu LIU Zhen-Xing CAO Jin-Bin Institute of Applied Physics&Computational Mathematics Beijing 100088 Laboratory of Space Weather Center for Space Science&Applied ResearchChinese Academy of SciencesBeijing 100080

A set of nonlinear fluid equations which include the effects of ion gyroradius is derived to describe Alfven vortex. The correction of finite ion gyroradius to the Alfven vortex in the inertial region is much more significant than that in the kinetic region. The amplitude of the vortex is enhanced in both regions. The scale of the vortex in the kinetic region becomes larger whereas it becomes smaller in the inertial region.

关键词： vortex radius radius

Improved phenomenological nuclear charge radius formulae with kernel ridge regression

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Chinese Physics C 2022年第7期46卷 129-137页

作者： Jian-Qin Ma Zhen-Hua Zhang Mathematies and Physics Department orth China Electric Power UniversityBeijing 102206China

The kernel ridge regression(KRR)method with Gaussian kernel is used to improve the description of the nuclear charge radius by several phenomenological *** widely used A^(1/3)A^(1/3),N^(1/3)N^(1/3)and Z^(1/3)Z^(1/3)formulae,and their improved versions by considering the isospin dependence are adopted as *** parameters in these six formulae are refitted using the Levenberg-Marquardt method,which give better results than the previous *** radius for each nucleus is predicted with the KRR network,which is trained with the deviations between experimental and calculated nuclear charge *** each formula,the resultant root-mean-square deviations of 884 nuclei with proton number Z≥8 Z≥8 and neutron number N≥8 N≥8 can be reduced to about 0.017fm after considering the modification of the KRR *** extrapolation ability of the KRR method for the neutron-rich region is examined carefully and compared with the radial basis function *** is found that the improved nuclear charge radius formulae by KRR method can avoid the risk of overfitting and have a good extrapolation *** influence of the ridge penalty term on the extrapolation ability of the KRR method is also *** last,the nuclear charge radii of several recently observed K and Ca isotopes have been analyzed.

关键词： nuclear charge radius phenomenological formulae kernel ridge regression

A Constraint of Black Hole Mass and the Inner Edge radius of Relativistic Accretion Disc

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Chinese Physics Letters 2011年第3期28卷 244-247页

作者： HE Liang HUANG Chang-Yin WANG Ding-Xiong School of Physics Huazhong University of Science and TechnologyWuhan 430074

A constraint to black hole(BH)accretion has previously been derived for the inner edge fixed at the innermost stable circular orbit(ISCO)and the innermost bound circular orbit(IBCO).This constraint is referred to as the mass-radius(MR)relation in this study,and the validity of the MR relation is discussed for different *** is shown that the product of the BH mass and the inner edge radius decreases monotonically in the accretion process for the inner edge located between IBCO and *** addition,we discuss the validity of the MR relation by considering the magnetic coupling(MC)effects of a Kerr BH with its surrounding *** theoretically the product of the BH mass and the radius of ISCO increases(decreases)with time for a BH spin greater(less)than some critical value in the MC process,this relation is approximately valid for an Eddington accretion rate persisting for a rather long time,such as more than 10^(6)***,we discuss the possible application of the MR relation to astrophysics.

关键词： radius constraint radius

Dependence of In—Tube Carbon Chain on the radius and Helicity of Single—Wall Carbon Nanotubes

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Chinese Physics Letters 2002年第1期19卷 98-100页

作者：刘红董锦明等 GroupofComputationalCondensedMatterPhysics NationalLaboratoryofSolidStateMicrostructuresandDepartmentofPhysicsNanjingUniversityNanjing210093 GroupofComputationalCondensedMatterPhysics NationalLabora

Using the Lennard-Jones interaction potential, we have studied the in-tube carbon-chain structure doped into single-wall carbon nanotubes (SWCNTs). Through minimizing the potential energy of the doped system, it is found that the optimal structure of the doping carbon chain is spiral, but not a straight line, when the radius of the SWCNT is larger than about 4.30 A

关键词： linearly ordered set Multi-Walled Nanotube radius Carbon Nanotubes Carbon Straight line radius DEPENDENCE Single-Walled Nanotube Helicity Potential energy Chains

Upper bounds for signless Laplacian Z-spectral radius of uniform hypergraphs

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Frontiers of Mathematics in China 2019年第1期14卷 17-24页

作者： Jun HE Yanmin LIU Junkang TIAN Xianghu LIU School of Mathematics Zunyi Normal College Zunyi 563006 China

Let ■ be a k-uniform hypergraph on n vertices with degree sequence △= d1≥…≥ dn =δ. In this paper, in terms of degree di , we give some upper bounds for the Z-spectral radius of the signless Laplacian tensor (Q(... 详细信息

关键词： Hypergraph adjacency tensor signless Laplacian tensor spectral radius

Sharp bounds for spectral radius of nonnegative weakly irreducible tensors

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Frontiers of Mathematics in China 2019年第5期14卷 989-1015页

作者： Lihua YOU Xiaohua HUANG Xiying YUAN School of Mathematical Sciences South China Normal UniversityGuangzhou 510631China Department of Mathematics Shanghai UniversityShanghai 200444China

We obtain the sharp upper and lower bounds for the spectral radius of a nonnegative weakly irreducible *** using the technique of the representation associate matrix of a tensor and the associate directed graph of the matrix,the equality cases of the bounds are completely characterized by graph theory *** these bounds to a nonnegative irreducible matrix or a connected graph(digraph),we can improve the results of ***,***,and ***[Linear Multilinear Algebra,2017,65(1):113-128],and obtain some new or known *** these bounds to a uniform hypergraph,we obtain some new results and improve some known results of ***,***,and ***[Linear Algebra Appl.,2015,484:540-549].Finally,we give a characterization of a strongly connected/c-uniform directed hypergraph,and obtain some new results by applying these bounds to a uniform directed hypergraph.

关键词： Nonnegative weakly irreducible tensors uniform(directed)hypergraph spectral radius bound

Sharp upper bounds for the adjacency and the signless Laplacian spectral radius of graphs

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Applied Mathematics(A Journal of Chinese Universities) 2019年第1期34卷 100-112页

作者： WU Xian-zhang LIU Jian-ping College of Mathematics and Computer Science Fuzhou University College of Mathematics and Data Science Minjiang University Key Laboratory of Intelligent Metro of Universities in Fujian Province Fuzhou University

Let G be a simple graph with n vertices and m edges. In this paper, we present some new upper bounds for the adjacency and the signless Laplacian spectral radius of graphs in which every pair of adjacent vertices has at least one common adjacent vertex. Our results improve some known upper bounds. The main tool we use here is the Lagrange identity.

关键词： graph spectral radius signless Laplacian spectral radius upper bound