摘要：
In this paper, we study the dynamical behavior of positive solution for a system of a rational third-order difference equation Xn+1 = Xn-2/B + Yn-2Yn-1Y2, Yn+1 = Yn-2/A + Xn-2Xn-1Xn, n = 0,1, ..., where A, B is an element of (0,infinity), X-2, X-1, X-0 is an element of (0,infinity); Y-2, Y-1, Y-0 is an element of (0,infinity)
作者机构：
[Tang, Li-Ming; Chen, Ke-Qiu; Chen, Xue-Kun; Zhou, Wu-Xing] Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha;[Tang, Li-Ming; Chen, Ke-Qiu; Chen, Xue-Kun; Zhou, Wu-Xing] 410082, China;[Xie, Zhong-Xiang] Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang;[Xie, Zhong-Xiang] 421002, China;410082, China
关键词：
Lattice thermal conductivity - Nonequilibrium molecular dynamics simulation - Period length - Phonon spectrum - Thermal transport - Thermal transport properties
摘要：
The thermal transport properties of the graphene and boron nitride superlattice (CBNSL) are investigated via nonequilibrium molecular dynamics simulations. The simulation results show that a minimum lattice thermal conductivity can be achieved by changing the period length of the superlattice. Additionally, it is found that the period length at the minimum shifts to lower values at higher temperatures, and that the depth of the minimum increases with decreasing temperature. In particular, at 200 K, the thermal conductivities of CBNSLs with certain specific period lengths are nearly equal to the corresponding values at 300 K. A detailed analysis of the phonon spectra shows that this anomalous thermal conductivity behavior is a result of strong phonon wave interference. These observations indicate a promising strategy for manipulation of thermal transport in superlattices. Published by AIP Publishing.
作者机构：
[Song, Weijie; Yang, Ye] Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, China;[Zhu, Ke] Department of Physics and Mathematics, Hunan Institute of Technology, Hengyang, China
通讯机构：
[Zhu, K] Hunan Inst Technol, Dept Math & Phys, Hengyang 421002, Peoples R China.
关键词：
Al and Ga co-doped ZnO;Thin films;Sputtering;Electrical properties;Substrate temperature
作者机构：
[Zhang, Yong; Xie, Zhong-Xiang] Hunan Inst Technol, Dept Math & Phys, Hengyang 421002, Peoples R China.;[Li, Ke-Min; Su, Ka-Lin; Luo, Wen-Hua] Hunan Inst Sci & Technol, Dept Phys & Elect Informat, Yueyang 414004, Peoples R China.
通讯机构：
[Xie, ZX] Hunan Inst Technol, Dept Math & Phys, Hengyang 421002, Peoples R China.
关键词：
Ballistic transport;Thermoelectricity;Nanoscale systems
摘要：
Ballistic thermoelectric properties in double-bend graphene nanoribbons (GNRs) are investigated by using the nonequilibrium Green's function. We find that due to the elastic scattering caused by the interface mismatching, the thermal conductance contributed by phonons is greatly reduced, while ballistic transport behaviors for electrons are dramatically demolished, and even some gaps can be opened at antiresonance energies. Near these antiresonance gaps, the maximum value of ZT (ZT(max)) can be observed, much larger than that for straight GNRs. Moreover, this ZT(max) can be effectively tuned by modulating the length or width of double-bend GNRs. (C) 2014 Elsevier B.V. All rights reserved.
摘要：
In this paper, a robust adaptive neural control design approach is presented for a class of perturbed strict-feedback nonlinear systems with unknown dead-zone. In the controller design, different from existing methods, all the virtual control laws need not be actually implemented at intermediate steps, and only one actual robust adaptive control law is constructed by approximating the lumped unknown function of the system with a single neural network at the last step. By this approach, the structure of the designed controller is much simpler since the causes for the problem of complexity growing in existing methods are eliminated. Stability analysis shows that the proposed scheme can guarantee the uniform ultimate boundedness of all the closed-loop system signals, and the steady-state tracking error can be made arbitrarily small by appropriately choosing control parameters. Simulation studies demonstrate the effectiveness and merits of the proposed approach. (C) 2014 Elsevier B.V. All rights reserved.
摘要：
For a (molecular) graph, the multiplicative Zagreb indices Pi(1)-index and Pi(2)-index are multiplicative versions of the ordinary Zagreb indices (M-1-index and M-2-index). In this note we report several sharp upper bounds for Pi(1)-index in terms of graph parameters including the order, size, radius, Wiener index and eccentric distance sum, and upper bounds for Pi(2)-index in terms of graph parameters including the order, size, the first Zagreb index, the first Zagreb coindex and degree distance.
作者机构：
[ Xie, Qiongtao ; Zhou, Zheng ; Hai, Wenhua ; Tan, Jintao ] Department of Physics, Ministry of Education, Hunan Normal University, Changsha 410081, China;[Zhou, Zheng ] Department of Physics and Mathematics, Hunan Institute of Technology, Hengyang 421002, China
通讯机构：
[Hai, WH] Hunan Normal Univ, Dept Phys, Changsha 410081, Hunan, Peoples R China.
关键词：
Analytical results - Coherent destruction of tunneling - Fine structures - High-frequency driving - Interacting bosons - Quantum tunneling - Second orders - Second-order correction
关键词：
Degree;harmonic index;Bounds;Topological index
摘要：
The harmonic index of a connected graph G, denoted by H(G), is defined as H(G) = Sigma(u upsilon is an element of E(G)) 2/d(u)+2 upsilon, where cit, is the degree of a vertex v in G. In this note, we extend a result of Zhong concerning the upper bound for harmonic index of unicyclic graphs to general connected graphs. In addition, we give a direct proof of Zhong's another result on the lower bound for harmonic index of trees.
摘要：
In this paper, we study the existence, asymptotic behavior of the positive solutions of a fuzzy nonlinear difference equation x(n+1) = Ax(n) + x(n-1)/B + x(n-1), n = 0, 0, ..., where (x(n)) is a sequence of positive fuzzy number, A, B are positive fuzzy numbers and the initial conditions x(-1), x(0) are positive fuzzy numbers.
期刊：
Chaos, Solitons and Fractals,2012年45(11):1423-1429 ISSN：0960-0779
通讯作者：
Hai, W.(whhai2005@yahoo.com.cn)
作者机构：
[Zheng Zhou] Department of Physics and Mathematics, Hunan Institute of Technology, Hengyang 421002, China;[Zheng Zhou; Yan Deng; Wenhua Hai; Qiongtao Xie] Department of Physics, Ministry of Education, Hunan Normal University, Changsha 410081, China
通讯机构：
[Hai, WH] Hunan Normal Univ, Minist Educ, Dept Phys, Changsha 410081, Hunan, Peoples R China.
关键词：
Anderson localization - Andersons - Attractive Bose-Einstein condensates - Chaotic transport - Delocalizations - Driving frequencies - Low probability - Matter wave solitons - Optical superlattice - Parameter regions - Positive dependence - Quasi-one-dimensional - Ratchet effects - Spatial localization - Time reversal symmetries
期刊：
INTERNATIONAL JOURNAL OF APPLIED MATHEMATICS AND COMPUTER SCIENCE,2011年21(4):649-658 ISSN：1641-876X
通讯作者：
Zhang, QH
作者机构：
[Yang, Lihui] Department of Mathematics, Hunan City University, Yiyang, Hunan 413000, China;[Zhang, Qianhong] Guizhou Key Laboratory of Economic Systems Simulation, School of Mathematics and Statistics, Guizhou College of Finance and Economics, Guiyang, Guizhou 550004, China;[Liao, Daixi] Basic Science Department, Hunan Institute of Technology, Hengyang, Hunan 421002, China
摘要：
Fuzzy cellular neural networks with time-varying delays are considered. Some sufficient conditions for the existence and exponential stability of periodic solutions are obtained by using the continuation theorem based on the coincidence degree and the differential inequality technique. The sufficient conditions are easy to use in pattern recognition and automatic control. Finally, an example is given to show the feasibility and effectiveness of our methods.
期刊：
INFORMATION SCIENCES,2014年270:226-236 ISSN：0020-0255
通讯作者：
Zhang, Q.(zqianhong68@163.com)
作者机构：
[ Yang, Lihui ] Department of Mathematics, Hunan City University, Yiyang, Hunan 413000, China;[Zhang, Qianhong ] Guizhou Key Laboratory of Economics System Simulation, Guizhou University of Finance and Economics, Guiyang, Guizhou 550004, China;[ Liao, Daixi ] Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang, Hunan 421002, China
摘要：
This paper deals with the existence, the boundedness and the asymptotic behavior of the positive solutions to a first order fuzzy Ricatti difference equation Xn+1 = A + X-n/B + X-n , n = 0,1,... where {X-n} is a sequence of positive fuzzy numbers, A, B and the initial value x(0) are positive fuzzy numbers. Moreover an example is given to demonstrate the effectiveness of the results obtained. (C) 2014 Elsevier Inc. All rights reserved.
作者机构：
[Kui Xiao] Hunan Inst Technol, Dept Math & Phys Teaching, Hengyang 421002, Peoples R China.;[Jian-Yang Zhu] Beijing Normal Univ, Dept Phys, Beijing 100875, Peoples R China.;[Xiao-Kai He] Hunan First Normal Univ, Dept Educ Sci, Changsha 410205, Hunan, Peoples R China.
通讯机构：
[Zhu, JY] Beijing Normal Univ, Dept Phys, Beijing 100875, Peoples R China.
摘要：
Phenomenological effect of the super-inflation in loop quantum cosmology (LQC) is discussed. We investigate the case that the Universe is filled with the interacting field between massive scalar field and radiation. Considering the damping coefficient Gamma as a constant, the changes of the scale factor during super-inflation with four different initial conditions are discussed, and we find that the changes of the scale factor depends on the initial values of energy density of the scalar field and radiation at the bounce point. But no matter which initial condition is chosen, the radiation always dominated at the late time. Moreover, we investigate whether the super-inflation can provide enough e-folding number. For the super-inflation starts from the quantum bounce point, the initial value of Hubble parameter H(t(i)) similar to 0, then it is possible to solve the flatness problem and horizon problem. As an example, following the method of [18] to calculate particle horizon on the condition that the radiation dominated at bounce point, and we find that the Universe has had enough time to be homogeneous and isotopic. (C) 2013 Elsevier B.V. All rights reserved.
摘要：
In this article, fuzzy bi-directional associative memory neural networks with distributed delays and impulses are considered. Some sufficient conditions for the existence and globally exponential stability of unique equilibrium point are established using fixed point theorem and differential inequality techniques. The results obtained are easily checked to guarantee the existence, uniqueness, and globally exponential stability of equilibrium point. MSC: 34K20; 34K13; 92B20
期刊：
JOURNAL OF APPLIED PHYSICS,2014年115(10) ISSN：0021-8979
通讯作者：
Xie, ZX
作者机构：
[ Li, Ke-Min ] Department of Physics and Electronics Information, Hunan Institute of Science and Technology, Yueyang 414004, China;[ Zhang, Yong ; Xie, Zhong-Xiang ; Yu, Xia ] Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang 421002, China;[ Chen, Qiao ] Department of Mathematics and Physics, Hunan Institute of Engineering, Xiangtan 411104, China
通讯机构：
[Xie, ZX] Hunan Inst Technol, Dept Math & Phys, Hengyang 421002, Peoples R China.
期刊：
Computers and Mathematics with Applications,2008年55(8):1854-1860 ISSN：0898-1221
通讯作者：
Ma, MJ
作者机构：
[Tang, Hengsheng] Department of Applied Mathematics, Hunan University, Changsha, Hunan 410082, China;[Luo, Wei] Fundamental Department, Hunan Institute of Technology, Hengyang, Hunan 421001, China;[Ma, Manjun; Tang, Hengsheng] Department of Mathematics and Physics, Nanhua University, Hengyang, Hunan 421001, China;[Li, Xu] Department of Nuclear Resource and Safety Engineering, Nanhua University, Hengyang, Hunan 421001, China
通讯机构：
[Ma, MJ] Nanhua Univ, Dept Math & Phys, Hengyang 421001, Hunan, Peoples R China.
关键词：
discrete elliptic boundary value problems;nontrivial solutions;existence;variational method;Mountain Pass Theorem
期刊：
JOURNAL OF APPLIED PHYSICS,2014年116(14) ISSN：0021-8979
通讯作者：
Zhang, Y
作者机构：
[Wang, Hai-Bin; Zhang, Yong; Yu, Xia; Xie, Zhong-Xiang] Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang, China;[Li, Ke-Min] Department of Physics and Electronics Information, Hunan Institute of Science and Technology, Yueyang, China
通讯机构：
[Zhang, Y] Hunan Inst Technol, Dept Math & Phys, Hengyang 421002, Peoples R China.
期刊：
JOURNAL OF APPLIED PHYSICS,2015年117(12) ISSN：0021-8979
通讯作者：
Zhang, Y
作者机构：
[Zhang, Yong] Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang, China;[Ning, Feng; Tang, Li-Ming; Zhang, Yong; Chen, Ke-Qiu] School of Physics and Electronics, Hunan University, Changsha, China;[Wang, Dan] Institute of Mathematics and Physics, Central South University of Forestry and Technology, Changsha, China
期刊：
Journal of Materials Chemistry C,2017年5(36):9429-9438 ISSN：2050-7526
通讯作者：
Tang, Li-Ming(lmtang@semi.ac.cn)
作者机构：
[ Zhang, Yong ] School of Mathematics, Physics and Energy Engineering, Hunan Institute of Technology, Hengyang;[ Zhang, Yong ] 421002, China;[Ning, Feng ] College of Physics and Electronic Engineering, Guangxi Teachers Education University, Nanning;[Ning, Feng ] 530001, China;[ Feng, Ye-Xin ; Tang, Li-Ming ; Chen, Ke-Qiu ; Zhang, Yong ; Ning, Feng ] Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha
通讯机构：
[Xie, ZX] Hunan Inst Technol, Dept Math & Phys, Hengyang 421002, Peoples R China.
关键词：
Diluted magnetic semiconductors;GaAs nanowires;DFT calculations
摘要：
Using first-principles calculations, we investigate the effect of surface passivation on the impurity distribution and magnetic properties in Mn-doped GaAs nanowires. A comparative analysis for the zinc-blend and wurtzite structures is made. Our results show that when the Mn-doped position shifts from the center to the edge, the Mn formational energy is reduced in the bare nanowire, while this behavior is reversed in the nanowire with surface dangling bonds passivated by pseudo-H. For the zinc-blend structured nanowire, a noticeable transformation from the antiferromagnetic to ferromagnetic coupling by surface passivation can be observed. However, for the wurtzite structured nanowire, the transformation cannot be observed, and the magnetic order exhibits the larger ferromagnetic coupling compared to that of the zinc-blend structure. A brief analysis of these results is given. (c) 2015 Published by Elsevier B.V.