检索结果-南通市图书馆

Recent Advances and Perspectives of Lewis Acidic Etching Route:An Emerging Preparation Strategy for MXenes

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2023年第5期15卷 187-235页

作者： Pengfei Huang Wei-qiang han School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027People’s Republic of China

Since the discovery in 2011,MXenes have become the rising star in the field of two-dimensional *** from the metallic-level conductivity,large and adjustable gallery spacing,low ion diffusion barrier,rich surface chemistry,superior mechanical strength,MXenes exhibit great application prospects in energy storage and conversion,sensors,optoelectronics,electromagnetic interference shielding and ***,two issues seriously deteriorate the further development of *** is the high experimental risk of common preparation methods such as HF etching,and the other is the difficulty in obtaining MXenes with controllable surface ***,Lewis acidic etching,as a brand-new preparation strategy for MXenes,has attracted intensive attention due to its high safety and the ability to endow MXenes with uniform ***,a comprehensive review of Lewis acidic etching method has not been reported ***,we first introduce the Lewis acidic etching from the following four aspects:etching mechanism,terminations regulation,in-situ formed metals and delamination of multi-layered ***,the applications of MXenes and MXene-based hybrids obtained by Lewis acidic etching route in energy storage and conversion,sensors and microwave absorption are carefully ***,some challenges and opportunities of Lewis acidic etching strategy are also presented.

关键词： Lewis acidic etching MXenes Etching mechanism Termination regulation In-situ formed metals Delamination Application

TWO-STEP SCHEME FOR BACKWARD STOCHASTIC DIFFERENTIAL EQUATIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2023年第2期41卷 287-304页

作者： qiang han Shaolin Ji Zhongtai Securities Institute for Financial Studies Shandong UniversityJinan 250100China

In this paper,a stochastic linear two-step scheme has been presented to approximate backward stochastic differential equations(BSDEs).A necessary and sufficient condition is given to judge the L 2-stability of our numerical *** stochastic linear two-step method possesses a family of 3-order convergence schemes in the sense of strong *** coefficients in the numerical methods are inferred based on the constraints of strong stability and n-order accuracy(n∈N^(+)).Numerical experiments illustrate that the scheme is an efficient probabilistic numerical method.

关键词： Backward stochastic differential equation Stochastic linear two-step scheme Local truncation error Stability and convergence

Prediction of nonlocal scale parameter for carbon nanotubes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2012年第9期55卷 1670-1678页

作者： LIANG YingJing han qiang Department of Engineering Mechanics School of Civil Engineering and Transportation South China University of Technology Guangzhou 510640 China

Based on the theory of nonlocal elasticity,a nonlocal shell model accounting for the small scale effect is developed for the bending characteristics of CNTs subjected to the concentrated *** this nonlocal shell model,explicit expressions are derived for the bending *** extract the proper values of nonlocal scale parameter,we have made molecular dynamics(MD) simulations for various radii and lengths of armchair and zigzag CNTs,the results of which are matched with those of nonlocal continuum *** is found that the present nonlocal elastic shell model with its appropriate values of nonlocal scale parameter has the capability to predict the bending behavior of CNTs,which is comparable with the results of MD ***,exact closed form solutions for the nonlocal scale parameter for zigzag and armchair CNTs are *** results show that nonlocal scale parameter is independent of the length of CNTs,and dependent on the radius of CNTs.

关键词： nonlocal elasticity nonlocal scale parameter carbon nanotubes nonlocal shell model molecular dynamics simulation

Effect of Interaction on the Majorana Zero Modes in the Kitaev Chain at Half Filling

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2018年第4期35卷 91-94页

作者： Zhidan Li qiang han Department of Physics Renmin University of China Beijing 100872 Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices Renmin University of China Beijing 100872

The one-dimensional interacting Kitaev chain at half filling is studied. The symmetry of the Hamiltonian is examined by dual transformations, and various physical quantities as a function of the fermion-fermion interaction U are calculated systematically using the density matrix renormalization group method. A special value of interaction Up is revealed in the topological region of the phase diagram. We show that at Up the ground states are strictly two-fold degenerate even though the chain length is finite and the zero-energy peak due to the Majorana zero modes is maximally enhanced and exactly localized at the end sites. Here Up may be attractive or repulsive depending on other system parameters. We also give a qualitative understanding of the effect of interaction under the self-consistent mean field framework.

关键词： In Effect of Interaction on the Majorana Zero Modes in the Kitaev Chain at Half Filling MZM

Dynamics of Bose-Einstein condensates in a one-dimensional optical lattice with double-well potential

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2013年第4期8卷 375-380页

作者： han-Lei Zheng qiang Gu Department of Physics University of Science and Technology Beijing Beijing 100083 China

We study dynamical behaviors of the weakly interacting Bose-Einstein condensate in the one- dimensional optical lattice with an overall double-well potential by solving the time-dependent Gross-Pitaevskii equation. It is observed that the double-well potential dominates the dynamics of such a system even if the lattice depth is several times larger than the height of the double-well potential. This result suggests that the condensate flows without resistance in the periodic lattice just like the case of a single particle moving in periodic potentials. Nevertheless, the effective mass of atoms is increased, which can be experimentally verified since it is connected to the Josephson oscillation frequency. Moreover, the periodic lattice enhances the nonlinearity of the double-well condensate, making the condensate more ＂self-trapped＂ in the ^-mode self-trapping regime.

关键词： Bose-Einstein condensate double-well potential optical lattice dynamical behavior

Effects of electron correlation on superconductivity in the Hatsugai-Kohmoto model

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第10期30卷 541-547页

作者： Huai-Shuang Zhu qiang han Department of Physics Renmin University of ChinaBeijing 100872China

Understanding how electrons form pairs in the presence of strong electron correlations demands going beyond the BCS *** study a correlated superconducting model where the correlation effects are accounted for by a U term local in momentum *** electron correlation is treated exactly while the electron pairing is treated approximately using the mean-field *** self-consistent equation for the pair potential is derived and *** contrary to expectation,a weak attractive U comparable to the pair potential can destroy the superconductivity,whereas for weak to intermediate repulsive U,the pair potential can be *** fidelity of the mean-field ground state is calculated to describe the strength of the elelectron *** show that the pair potential is not equal to the single-electron superconducting gap for the strongly correlated superconductors,in contrast to the uncorrelated BCS limit.

关键词： strong correlated superconductivity exactly solvable model mean-field theory

Ginzburg-Landau Equations for (d+s)-Wave Superconductors in a Non-Fermi Liquid

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1998年第10期15卷 742-744页

作者： han qiang ZhanG Li-yuan Department of Physics Peking UniversityBeijing 100871

The Ginzburg-Landau equations are microscopically derived for an anisotropic(d+s)-wave superconductor by assuming a non-Fermi-liquid normal state characterized by a nonvanishing exponentα.The transition temperature Tc as functions ofαand the anisotropic parameter g which measures the ab anisotropy is *** is found that the anisotropic effect,which results in the enhancement of T_(c) and the nonzero bulk value of the s-wave order parameter,is strengthened due to the non-Fermi behavior.

关键词： behavior. Fermi Landau

Nonlinear Degenerate Parabolic Equations with Time-dependent Singular Potentials for Baouendi–Grushin Vector Fields

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2015年第1期31卷 123-139页

作者： Jun qiang han Qian Qiao GUO Department of Applied Mathematics Northwestern Polytechnical University

In this paper, we are concerned with the following three types of nonlinear degenerate parabolic equations with time-dependent singular potentials： uq/ t=▽α·（‖z‖^-pγ｜▽αu｜^p-2▽αu）＋V（z, t）u^p-1, uq/ t=▽α·（‖z‖^-2γ▽αu^m）＋V（z, t）u^m, uq/ t=u^μ▽α·（u^τ｜▽αu｜^p-2▽αu）＋V（z, t）u^p-1＋μ＋τin a cylinder Ω×（0, T） with initial condition u（z, 0）=u0（z） ≥ 0 and vanishing on the boundary Ω×（0, T）, where Ω is a Carnot-Carathéodory metric ball in Rd＋k and the time-dependent singular potential function is V（z, t） ∈ L^1loc （Ω×（0, T））. We investigate the nonexistence of positive solutions of these three problems and present our results on nonexistence.

关键词： Nonlinear degenerate parabolic equations Baouendi-Grushin vector fields positive solu-tions~ nonexistence Hardy inequality

Combined torsional buckling of double-walled carbon nanotubes with axial load in the multi-field coupled condition

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2011年第9期54卷 1659-1665页

作者： SUN YuGang YAO XiaoHu han qiang Department of Engineering Mechanics School of Civil Engineering and Transportation South China University of Technology Guangzhou 510640 China

The present study has theoretically investigated the combined torsional buckling of double-walled carbon nanotubes (DWCNTs) with axial load in the multi-field coupled condition. The effects of torsion, axial load, thermal-electrical change, surrounding elastic medium and the Van der Waals forces are all taken into consideration. The governing equation of buckling for CNTs subjected to thermo-electro-mechanical loadings has been established based on an elastic shell model of continuum mechanics. Reasonable simplifications are made to get the explicit expression of the critical buckling shear stress of DWCNTs, and numerical experiments are conducted for further research. It is shown that under certain electric and temperature field the critical buckling shear stress of DWCNTs only depends on the wave number of buckling modes. On the other hand, all the related impact factors have enormous influence on the critical buckling shear stress under a certain buckling mode. The critical buckling shear stress changes linearly with the axial-to-shear stress ratio, as well as the thermal and electric change. Axial compression tends to make DWCNTs unstable, while axial tension benefits the buckling stability. The critical buckling shear stress is directly proportional to the applied voltage. At room or lower temperature, the critical shear stress for infinitesimal buckling increases as the temperature change increases, while it decreases at a higher temperature. The conclusions are useful for the design of nano-structures related to the buckling stability of DWCNTs.

关键词： Carbon nanotubes buckling multi-field coupling