Chirality- and thickness-dependent thermal conductivity of few-layer graphene: a molecular dynamics study

The thermal conductivity of graphene nanoribbons (layer from 1 to 8 atomic planes) is investigated by using the nonequilibrium molecular dynamics method. We present that the room-temperature thermal conductivity decays monotonically with the number of the layers in few-layer graphene. The superiority of zigzag graphene in thermal conductivity is only available in high temperature region and disappears in multi-layer case. It is explained that the phonon spectral shrink in high frequency induces the change of thermal conductivity. It is also reported that single-layer graphene has better ballistic transport property than the multi-layer graphene.Comment: 3 figure

Observation of the first iso-spin Charmonium-like State Zc(4020)Z_c(4020) }

In this paper, we present a new experimental progress in brief on the recent observation of the charged charmonium-like state Z_c(4020)^{+/-} states and its iso-spin partner Z_c(4020)^{0} in pi pi hc process at the BESIII experiment. The charged Z_{c}(4020) is its decay into \pi^{+/-} hc final state, and carries electric charge, thus it contains at least four quarks. The observation of both charge and neutral state makes Z_{c}(4020) the first iso-spin triplet Z_{c} state observed in experiment.Comment: 5 pages, 7 figure

Thermal conductivity of deformed carbon nanotubes

We investigate the thermal conductivity of four types of deformed carbon nanotubes by using the nonequilibrium molecular dynamics method. It is reported that various deformations have different influence on the thermal properties of carbon nanotubes. For the bending carbon nanotubes, the thermal conductivity is independent on the bending angle. However, the thermal conductivity increases lightly with XY-distortion and decreases rapidly with Z-distortion. The thermal conductivity does not change with the screw ratio before the breaking of carbon nanotubes but decreases sharply after the critical screw ratio.Comment: 6figure

Lie symmetry and exact solution of (2+1)-dimensional generalized Kadomtsev-Petviashvili equation with variable coefficients

The simple direct method is adopted to find Non-Auto-Backlund transformation for variable coefficient non-linear systems. The (2+1)-dimensional generalized Kadomtsev-Petviashvili equation with variable coefficients is used as an example to elucidate the solution procedure, and its symmetry transformation and exact solutions are obtained

Magnetization Reversal Modes in Short Nanotubes with Chiral Vortex DomainWalls

Micromagnetic simulations of magnetization reversal were performed for magnetic nanotubes of a finite length, L, equal to 1 and 2 mum, 50 and 100 nm radii, R, and uniaxial anisotropy with "easy axis" parallel to the tube length. I.e., we considered relatively short nanotubes with the aspect ratio L/R in the range 10-40. The non-uniform curling magnetization states on both ends of the nanotubes can be treated as vortex domain walls (DW). The domain wall length, Lc, depends on the tube geometric parameters and the anisotropy constant Ku, and determines the magnetization reversal mode, as well as the switching field value. For nanotubes with relative small values of Lc (Lc/L < 0.2) the magnetization reversal process is characterized by flipping of the magnetization in the middle uniform state. Whereas, for relative large values of Lc, in the reverse magnetic field, coupling of two vortex domain walls with opposite magnetization rotation directions results in the formation of a specific narrow Neel type DW in the middle of the nanotube. The nanotube magnetization suddenly aligns to the applied field at the switching field, collapsing the central DW