Kinetic theory for a simple modeling of phase transition: Dynamics out of local equilibrium

This is a continuation of the previous work (Takata & Noguchi, J. Stat. Phys., 2018) that introduces the presumably simplest model of kinetic theory for phase transition. Here, main concern is to clarify the stability of uniform equilibrium states in the kinetic regime, rather than that in the continuum limit. It is found by the linear stability analysis that the linear neutral curve is invariant with respect to the Knudsen number, though the transition process is dependent on the Knudsen number. In addition, numerical computations of the (nonlinear) kinetic model are performed to investigate the transition processes in detail. Numerical results show that (unexpected) incomplete transitions may happen as well as clear phase transitions.Comment: 21 pages, 7 figure

Impact of the semiconductor on hexagonal-BN structure for power-supply on chip applications

This paper evaluates the semiconductor on hexagonal-BN (h-BN) structure for power-supply on chip applications based on numerical simulations. Hexagonal-BN is used as an insulator of semiconductor -on-insulator (SOI) structure. Hexagonal-BN based SOI structure with through-silicon-via(TSV) shows higher heat dissipation performance without degrading electrical characteristics compared with the conventional SOI structure.2018 International Conference on Solid State Devices and Materials(SSDM2018), September9-13, 2018, Hongo Campus, The University of Tokyo, Tokyo, Japa

Kinetic model for the phase transition of the van der Waals fluid

This is a continuation of previous works [S. Takata and T. Noguchi, J. Stat. Phys. 172, 880 (2018); S. Takata, T. Matsumoto, A. Hirahara, and M. Hattori, Phys. Rev. E 98, 052123 (2018)]. The simple model proposed in the previous works is extended to be free from the isothermal assumption. The new model conserves the total mass, momentum, and energy in the periodic domain. A monotone functional is found, assuring the H theorem for the new model. Different approaches are taken to tell apart the stable, the metastable, and the unstable uniform equilibrium state. Numerical simulations are also conducted for spatially one-dimensional cases to demonstrate various features occurring in the time evolution process. A prediction method for the profile at the stationary state is discussed as well

Highly Sensitive Local Surface Plasmon Resonance in Anisotropic Au Nanoparticles Deposited on Nanofibers

This paper reports the facile and high-throughput fabrication method of anisotropic Au nanoparticles with a highly sensitive local surface plasmon resonance (LPR) using cylindrical nanofibers as substrates. The substrates consisting of nanofibers were prepared by the electrospinning of poly(vinylidene fluoride) (PVDF). The Au nanoparticles were deposited on the surface of electrospun nanofibers by vacuum evaporation. Scanning electron microscopy revealed the formation of a curved Au island structure on the surface of cylindrical nanofibers. Polarized UV-visible extinction spectroscopy showed anisotropy in their LPR arising from the high surface curvature of the nanofiber. The LPR of the Au nanoparticles on the thinnest nanofiber with a diameter of ~100 nm showed maximum refractive index (RI) sensitivity over 500 nm/RI unit (RIU). The close correlation between the fiber diameter dependence of the RI sensitivity and polarization dependence of the LPR suggests that anisotropic Au nanoparticles improve RI sensitivity