期刊：
Journal of Fluids and Structures,2010年26(5):793-803 ISSN：0889-9746
通讯作者：
Guo, C. Q.
作者机构：
[Guo, C. Q.; Zhang, C. H.] Tsinghua Univ, Dept Hydraul Engn, Beijing 100084, Peoples R China.;[Guo, C. Q.] Univ S China, Sch Math & Phys, Hengyang 421001, Hunan, Peoples R China.;[Paidoussis, M. P.] McGill Univ, Dept Mech Engn, Montreal, PQ H3A 2K6, Canada.
通讯机构：
[Guo, C. Q.] Tsinghua Univ, Dept Hydraul Engn, Beijing 100084, Peoples R China.
关键词：
Fluid-conveying pipe<&wdkj&>Equation of motion<&wdkj&>Critical flow velocity<&wdkj&>Laminar flow<&wdkj&>Turbulent flow
摘要：
Considering the non-uniformity of the flow velocity distribution in fluid-conveying pipes caused by the viscosity of real fluids, the centrifugal force term in the equation of motion of the pipe is modified for laminar and turbulent flow profiles. The flow-profile-modification factors are found to be 1.333, 1.015-1.040 and 1.035-1.055 for laminar flow in circular pipes, turbulent flow in smooth-wall circular pipes and turbulent flow in rough-wall circular pipes, respectively. The critical flow velocities for divergence in the above-mentioned three cases are found to be 13.4%, 0.74-1.9% and 1.7-2.6%, respectively, lower than that with plug flow, while those for flutter are even lower, which could reach 36% for the laminar flow profile. By introducing two new concepts of equivalent flow velocity and equivalent mass, fluid-conveying pipe problems with different flow profiles can be solved with the equation of motion for plug flow. (C) 2010 Elsevier Ltd. All rights reserved.
摘要：
In this paper, a six-neuron BAM neural network model with discrete delays is considered. By analyzing the associated characteristic transcendental equation, the linear stability of the model is investigated and Hopf bifurcation is demonstrated. Some explicit formulae determining the stability and the direction of the Hopf bifurcation periodic solutions bifurcating from Hopf bifurcations are obtained by using the normal form method and center manifold theory. Finally, numerical simulations supporting the theoretical analysis are given. (C) 2010 Elsevier B.V. All rights reserved.
作者机构：
[Du, Dan; Peng, Zhi-Hua; Chen, Xue-Kun] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Liu, Jun] Cent S Univ, Coll Chem & Chem Engn, Changsha 410083, Hunan, Peoples R China.;[Chen, Ke-Qiu] Hunan Univ, Sch Phys & Elect, Dept Appl Phys, Changsha 410082, Hunan, Peoples R China.;[Chen, Ke-Qiu] Synerget Innovat Ctr Quantum Effects & Applicat H, Changsha 410081, Hunan, Peoples R China.
通讯机构：
[Chen, Xue-Kun] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Chen, Ke-Qiu] Hunan Univ, Sch Phys & Elect, Dept Appl Phys, Changsha 410082, Hunan, Peoples R China.;[Chen, Ke-Qiu] Synerget Innovat Ctr Quantum Effects & Applicat H, Changsha 410081, Hunan, Peoples R China.
摘要：
Nonlinear thermal transport in graphene/hexagonal boron nitride (h-BN) heterostructure is investigated by the nonequilibrium molecular dynamics method. It is found that negative differential thermal resistance (NDTR) will appear as the applied temperature difference increases. Detailed phonon spectra analysis reveals that the excited out-of-plane acoustic wave plays an important role in the heat transport across such interface. That is, the mechanical wave results in a significant mismatch between the lattice vibrations of graphene and h-BN domains and hinders interfacial thermal transport. In addition, NDTR can be tuned through the temperature parameter. Interestingly, the regime of NDTR becomes smaller and eventually vanishes with increasing the heterostructure length. However, NDTR is insensitive to the variation of system width. The work may be useful for nanoscale thermal managements utilizing the graphene/h-BN heterostructure. Published by AIP Publishing.
摘要：
In this paper, a class of delayed predator-prey model of prey dispersal in two-patch environments is considered. By analyzing the associated characteristic transcendental equation, its linear stability is investigated and Hopf bifurcation is demonstrated. Some explicit formulae determining the stability and the direction of the Hopf bifurcation periodic solutions bifurcating from Hopf bifurcations are obtained by using the normal form theory and center manifold theory. Some numerical simulation for justifying the theoretical analysis are also provided. Finally, biological explanations and main conclusions are given. (C) 2010 Elsevier Inc. All rights reserved.
摘要：
In this paper, a three-species predator-prey system with two delays is investigated. By choosing the sum tau of two delays as a bifurcation parameter, we first show that Hopf bifurcation at the positive equilibrium of the system can occur as tau crosses some critical values. Second, we obtain the formulae determining the direction of the Hopf bifurcations and the stability of the bifurcating periodic solutions by using the normal form theory and center manifold theorem. Finally, numerical simulations supporting our theoretical results are also included. (C) 2011 Elsevier B.V. All rights reserved.
摘要：
In this paper, a two-species Lotka-Volterra predator-prey model with two delays is considered. By analyzing the associated characteristic transcendental equation, the linear stability of the positive equilibrium is investigated and Hopf bifurcation is demonstrated. Some explicit formulae for determining the stability and direction of Hopf bifurcation periodic solutions bifurcating from Hopf bifurcations are obtained by using normal form theory and center manifold theory. Some numerical simulations for supporting the theoretical results are also included.
作者：
Li, Jing-Chun;Gong, Xue-Yu*;Dong, Jia-Qi;Wang, Jun;Yin, Lan
期刊：
Chinese Physics B,2016年25(4):45201-1-45201-8 ISSN：1674-1056
通讯作者：
Gong, Xue-Yu
作者机构：
[Gong, Xue-Yu; Li, Jing-Chun] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Wang, Jun; Dong, Jia-Qi] Southwestern Inst Phys, POB 432, Chengdu 610041, Peoples R China.;[Yin, Lan] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
通讯机构：
[Gong, Xue-Yu] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.
关键词：
HL-2M;electron–cyclotron current drive;neoclassical tearing modes;sawtooth
摘要：
The capabilities of current drive, neoclassical tearing mode (NTM) stabilization, and sawtooth control are analyzed for the electron–cyclotron wave (ECW) system in a HL-2M tokamak. Better performance of the upper launcher is demonstrated in comparison with that of a dropped upper launcher, in terms of J_(EC)/J_(bs) for NTM stabilization and I_(ECCD)/(?_ρ(tor))~2 for sawtooth control. 1-MW ECW power is enough for the 3/2 NTM stabilization, and 1.8-MW ECW power is required to suppress 2/1 NTM in a single null divertor equilibrium with 1.2-MA toroidal current with the upper launcher. Optimization simulation of electron–cyclotron current drive (ECCD) is carried out for three mirrors in an equatorial port, indicating that the middle mirror has a good performance compared with the top and bottom mirrors. The results for balanced co-and counter-ECCD in an equatorial port are also presented.
摘要：
Based on the ideal solution approximation, the model for size-dependent melting temperature of pure metal nanoparticles is extended to binary alloy systems. The developed model, free of any adjustable parameter, demonstrates that the melting temperature is related to the size and composition of alloy nanoparticles. The melting temperature of CuNi, PbBi and SnIn binary alloy nanocrystals is found to be consistent with the experiments and molecular dynamics simulations. The research reveals that alloy nanocrystals have similar melting nature as pure metal.
摘要：
In this paper, we study the multiplicity and concentration of solutions for the following critical fractional Schrödinger–Poisson system: \begin{eqnarray*} \left\{ \begin{array}{ll} \epsilon^{2s}(-\triangle)^{s} {u}+ V(x)u+\phi u =f(u)+|u|^{2^*_{s}-2}u &\mbox{in}\,\,\R^3, \\[2.5mm] \epsilon^{2t}(-\triangle)^{t}{\phi}=u^2 &\mbox{in}\,\, \R^3, \end{array} \right. \end{eqnarray*} where <i>ϵ<i/>> 0 is a small parameter, (− △ )<sup><i>α<i/><sup/> denotes the fractional Laplacian of order <i>α<i/> = <i>s,t<i/> ∈ (0,1), where 2<sub><i>α<i/><sub/><sup>∗<sup/>6/3−2α is the fractional critical exponent in Dimension 3; <i>V<i/> ∈ <i>C<i/><sup>1<sup/>(ℝ<sup>3<sup/>,ℝ<sup>+<sup/>) and <i>f<i/> is subcritical. We first prove that for <i>ϵ<i/>> 0 sufficiently small, the system has a positive ground state solution. With minimax theorems and Ljusternik–Schnirelmann theory, we investigate the relation between the number of positive solutions and the topology of the set where <i>V<i/> attains its minimum for small <i>ϵ<i/>. Moreover, each positive solution <i>u<i/><sub><i>ϵ<i/><sub/> converges to the least energy solution of the associated limit problem and concentrates around a global minimum point of <i>V<i/>.
期刊：
Chinese Journal of Electronics,2002年11(4):469-471 ISSN：1022-4653
通讯作者：
Pan, LQ
作者机构：
[Pan, LQ] Huazhong Univ Sci & Technol, Dept Control Sci & Engn, Wuhan 430074, Peoples R China.;Nahua Univ, Inst Engn & Technol, Dept Math & Phys, Hengyang 421001, Peoples R China.
通讯机构：
[Pan, LQ] Huazhong Univ Sci & Technol, Dept Control Sci & Engn, Wuhan 430074, Peoples R China.
关键词：
DNA computing;NP-complete problem;maximal clique problem
摘要：
The maximal clique problem is an NP (nondeterministic polynomial time)-complete problem. We present an algorithm that solves maximal clique problem within the framework of a surface-based model of computation. The time complexity of our algorithm is O(n2), and the number of kinds of short oligonucleotides needed to encode maximal clique problem is n + 3, where n is the size of the graph. In our algorithm, immobilizing DNA (deoxyribonucleic acid) strands to a solid surface reduces the possibility of error resulting from the loss of DNA strands in solution. A solution-based algorithm solving maximal clique problem has previously been proposed by Qi Ouyang et al.. In their algorithm, the number of enzyme is equal to the number of vertices of the graph, which causes the difficulty of encoding and scaling up, because the DNA sequences of restriction enzyme sites should not be present in otherwhere. Using surface-based model, we designed an algorithm for maximal clique problem, which needs only one enzyme.
期刊：
Mathematical Problems in Engineering,2014年2014(1-2) ISSN：1024-123X
通讯作者：
Ouyang, ZG
作者机构：
[Ouyang, Zigen; Wang, Hui] Nanhua Univ, Sch Math & Phys, Hengyang 421001, Peoples R China.
通讯机构：
[Ouyang, ZG ] Nanhua Univ, Sch Math & Phys, Hengyang 421001, Peoples R China.;Nanhua Univ, Sch Math & Phys, Hengyang 421001, Peoples R China.
摘要：
A model for Influence of Nuclear-Electricity Industry on Area Economy is established in this paper; we obtain an existence condition of solutions. Further, the approximation conditions are also constructed; the economic aggregate will tends to the equilibriums point as time tend to infinity.
摘要：
In this paper, we consider a ratio-dependent predator-prey system with diffusion. And we mainly discuss the following problems: (1) stability and Hopf bifurcation analysis of the positive equilibrium for the reduced ODE system; (2) Diffusion-driven instability of the equilibrium solution; (3) Hopf bifurcations for the corresponding diffusion system with homogeneous Neumann boundary conditions. In order to verify our theoretical results, some numerical simulations are also included, respectively. (C) 2010 Elsevier Ltd. All rights reserved.
作者机构：
[Yang, Liu] Hengyang Normal Univ, Dept Math & Comp Sci, Hengyang 421008, Hunan, Peoples R China.;[Ouyang, Zigen; Liu, Zhisu] Univ South China, Sch Math & Phys, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Liu, Zhisu] Univ South China, Sch Math & Phys, Hengyang 421001, Hunan, Peoples R China.
关键词：
Multiplicity<&wdkj&>Kirchhoff type equation<&wdkj&>Critical growth
摘要：
In this paper, we study the following Kirchhoff type equation with critical growth {-(a + b integral(Omega) vertical bar del u vertical bar(2)dx) del u = lambda u + mu vertical bar u vertical bar(2)u + vertical bar u vertical bar(4)u in Omega, u = 0 on partial derivative Omega, where a > 0, b >= 0 and Omega is a smooth bounded domain in R-3. When the real parameter mu is larger than some positive constant, we investigate the multiplicity of nontrivial solutions for the above problem with parameter lambda belonging to a left neighborhood of the Dirichlet eigenvalue of the Laplacian operator -Delta. (C) 2016 Elsevier Ltd. All rights reserved.
摘要：
In this paper, we propose a theoretical scheme of many-ghost imaging in terms of Nth-order correlated thermal light. We obtain the Gaussian thin lens equations in the many-ghost imaging protocol. We show that it is possible to produce N−1 ghost images of an object at different places in a nonlocal fashion by means of a higher order correlated imaging process with an Nth-order correlated thermal source and correlation measurements. We investigate the visibility of the ghost images in the scheme and obtain the upper bounds of the visibility for the Nth-order correlated thermal-light ghost imaging. It is found that the visibility of the ghost images can be dramatically enhanced when the order of correlation becomes larger. It is pointed out that the many-ghost imaging phenomenon is an observable physical effect induced by higher order coherence or higher order correlations of optical fields.
