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Search Results: 1 - 10 of 74309 matches for " Wei-Rong Zhong "
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Different thermal conductance of the inter- and intra-chain interactions in a double-stranded molecular structure
Wei-Rong Zhong
Physics , 2011, DOI: 10.1103/PhysRevE.81.061131
Abstract: A double-stranded system, modeled by a Frenkel-Kontorova lattice, is studied through nonequilibrium molecular dynamics simulations. We have investigated the thermal conductance influenced by the intra-chain interaction as well as by the inter-chain interaction. It is found that the intra-chain interaction always enhance the thermal conductance. The inter-chain interaction, however, has a positive effect on the thermal conductance in the case of strong nonlinear potential, and has a negative effect on the thermal conductance in the case of weak nonlinear potential. This phenomenon can be explained by the transition of thermal transport mode and the phonon band shift of the particles. It is suggested that the inter-and intra-chain interactions present different thermal properties in double-stranded lattices.
T-Shape Molecular Heat Pump
Wei-Rong Zhong,Bambi Hu
Physics , 2011, DOI: 10.1103/PhysRevB.81.205401
Abstract: We report on the first molecular device of heat pump modeled by a T-shape Frenkel-Kontorova lattice. The system is a three-terminal device with the important feature that the heat can be pumped from the low-temperature region to the high-temperature region through the third terminal. The pumping action is achieved by applying a stochastic external force that periodically modulates the atomic temperature. The temperature, the frequency and the system size dependence of heat pump are briefly discussed.
Dimension dependence of negative differential thermal resistance in graphene nanoribbons
Bao-quan Ai,Wei-rong Zhong,Bambi Hu
Physics , 2014, DOI: 10.1021/jp303431k
Abstract: Negative differential thermal resistance (NDTR) in approximate graphene nanoribbons (GNRs) is investigated from one dimension to three dimensions by using classical molecular dynamics method. For single-layer GNRs, NDTR can not be observed for very narrow GNRs (one dimension), NDTR appears when the width of GNRs increases (two dimensions). However, NDTR disappears gradually on further increasing the width. For multiple-layer GNRs, when the number of the layers increases, GNRs becomes from two-dimensional system to three-dimensional system, NDTR regime reduces and eventually disappears. In addition, when the length of GNRs increases, NDTR regime also reduces and vanishes in the thermodynamic limit. These effects may be useful for designing thermal devices where NDTR plays an important role.
Double negative differential thermal resistance induced by the nonlinear on-site potentials
Bao-quan Ai,Wei-rong Zhong,Bambi Hu
Physics , 2012, DOI: 10.1103/PhysRevE.83.052102
Abstract: We study heat conduction through one-dimensional homogeneous lattices in the presence of the nonlinear on-site potentials containing the bounded and unbounded parts, and the harmonic interaction potential. We observe the occurrence of double negative differential thermal resistance (NDTR), namely, there exist two regions of temperature difference, where the heat flux decreases as the applied temperature difference increases. The nonlinearity of the bounded part contributes to NDTR at low temperatures and NDTR at high temperatures is induced by the nonlinearity of the unbounded part. The nonlinearity of the on-site potentials is necessary to obtain NDTR for the harmonic interaction homogeneous lattices. However, for the anharmonic homogeneous lattices, NDTR even occurs in the absence of the on-site potentials, for example the rotator model.
Thermal rectification in thickness-asymmetric graphene nanoribbons
Wei-Rong Zhong,Wei-Hao Huang,Xi-Rong Deng,Bao-Quan Ai
Physics , 2011, DOI: 10.1063/1.3659474
Abstract: Thermal rectification in thickness asymmetric graphene nanoribbons connecting single-layer with multi-layer graphene is investigated by using classical nonequilibrium molecular dynamics. It is reported that the graphene nanoribbons with thickness-asymmetry have a good thermal rectification. The thermal rectification factor depends on temperature as well as the thickness-ratio of the two-segment. Our results provide a direct evidence that the thermal rectifier can be achieved in a nanostructure crossing two- and three-dimension.
Enhancement effect of asymmetry on the thermal conductivity of double-stranded chain systems

Zhang Mao-Ping,Zhong Wei-Rong,Ai Bao-Quan,

中国物理 B , 2011,
Abstract: Using nonequilibrium molecular dynamics simulations, we study the thermal conductivity of asymmetric double chains. We couple two different single chains through interchain coupling to build three kinds of asymmetric double-stranded chain system: intrachain interaction, external potential, and mass asymmetric double chains. It is reported that asymmetry is helpful in improving the thermal conductivity of the system. We first propose double-heat flux channels to explain the influence of asymmetric structures on the thermal conductivity. The phonon spectral behaviour and finite size effect are also included.
Mass Transport Induced by Heat Current in Carbon Nanotubes
Wei-Rong Zhong,Zhi-Cheng Xu,Ming-Ming Yang,Bao-Quan Ai
Journal of Nanomaterials , 2013, DOI: 10.1155/2013/386068
Abstract: Transport of helium atoms in the carbon nanotubes is investigated in the presence of temperature gradients. The heat current flowing along the carbon nanotubes can induce a stable directed transport of helium; it is demonstrated that the heat current density rather than the temperature gradient performs as a fundamental physical factor to the mass transport. We provide an alternative route to control the mass transport by using heat. Our results reported here are also relevant for understanding the transition from thermal energy to mechanical energy. 1. Introduction The study of transport is always a challenge issue with incalculable value to us. Thermal and mass transports are the two important transports and have attracted substantial concerns [1]. In thermal transport, thermal conduction is the transfer of heat energy by microscopic diffusion and collisions of particles or quasiparticles within a body due to a temperature gradient. The mass transport refers to the orientated flow of particles. Even if thermal transport is a deviation from mass transport in physical principle, researchers are always trying to find out their inherent relationship [2, 3]. Recently, an experimental result shows that thermal gradients can drive the subnanometer motion of cargoes along carbon nanotubes (CNTs) [4]. Another numerical result shows that the fullerene encapsulated in carbon nanotubes can also be driven by temperature gradients [5]. More and more studies focus on nanoparticle manipulation using heat [6–8]. A model of carbon nanotubes filled with fullerene (C60) reported that the temperature can pumping large particles [9]. The Langevin model of a thermally -driven double-walled nanotubes motor has described the dynamics of nanoelectromechanical device activated by heat [10]. It was also reported that the velocity of C60 induced by temperature gradients had a linear relationship with heat flux [6]. These few previous efforts suggest that the heat originated from temperature gradients can induce the motion of particles. However, the underline physics of mass transport driven by heat is still not so clear. In this paper, we will study the carbon nanotubes filled with helium (He) atoms and investigate the transport of He atoms induced by the heat flowing through the CNTs. By constructing the relationship between the mass flux and the heat current, we try to reveal some fundamental physics about the energy transport and its transformation. The obtained results are of significance for understanding the thermally induced mass transport in quasi-one-dimensional
Negative differential thermal resistance induced by ballistic transport
Wei-Rong Zhong,Ping Yang,Bao-Quan Ai,Zhi-Gang Shao,Bambi Hu
Physics , 2009, DOI: 10.1103/PhysRevE.79.050103
Abstract: Using nonequilibrium molecular-dynamics simulations, we study the temperature dependence of the negative differential thermal resistance that appears in two-segment Frenkel-Kontorova lattices. We apply the theoretical method based on Landauer equation to obtain the relationship between the heat current and the temperature, which states a fundamental interpretation about the underlying physical mechanism of the negative differential thermal resistance. The temperature profiles and transport coefficients are demonstrated to explain the crossover from diffusive to ballistic transport. The finite-size effect is also discussed.
Stochastic resonance in the growth of a tumor induced by correlated noises
Wei-Rong Zhong,Yuan-Zhi Shao,Zhen-Hui He
Physics , 2005,
Abstract: Multiplicative noise is found to divide the growth law of tumors into two parts in a logistic model, which is driven by additive and multiplicative noises simultaneously. The Fokker-Planck equation was also derived to explain the fact that the influence of the intensity of multiplicative noise on the growth of tumor cells has a stochastic resonance-like characteristic. An appropriate intensity of multiplicative noise is benefit to the growth of the tumor cells. The correlation between two sorts of noises weakens the stochastic resonance-like characteristic. Homologous noises promote the growth of the tumor cells.
Noise-induced first-order transition in anti-tumor immunotherapy
Wei-Rong Zhong,Yuan-Zhi Shao,Zhen-Hui He
Physics , 2005,
Abstract: We studied the single-variable dynamics model of the tumor growth. A first-order phase transition induced by an additive noise is shown to reproduce the main features of tumor growth under immune surveillance. The critical average cells population has a power-law function relationship with the immune coefficient.
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