An iterative implicit diagonally-dominant factorization algorithm for solving the Navier-Stokes equations

Presented here is an algorithm for solving the multidimensional unsteady Navier-Stokes equations for compressible flows. It is based on a diagonally-dominant approximate factorization procedure. The factorization error and the timewise linearization error associated with this procedure are reduced by performing Newton-type inner iterations at each time step. The inviscid fluxes are evaluated by the fourth-order central differencing scheme amended with a numerical dissipation directly proportional to the entire dissipative part of the truncation error intrinsic to the third order biased upwind scheme. The important features of the proposed solution are elucidated by the numerical results of the convection of a vortex and the backward-facing step flows

Observation and Understanding of the Initial Unstable Electrical Contact Behaviors

Reliable and long-lifetime electrical contact is a very important issue in the field of radio frequency microelectromechanical systems (MEMS) and in energy transmission applications. In this paper, the initial unstable electrical contact phenomena under the conditions of micro-newton-scale contact force and nanometer-scale contact gap have been experimentally observed. The repetitive contact bounces at nanoscale are confirmed by the measured instantaneous waveforms of contact force and contact voltage. Moreover, the corresponding physical model for describing the competition between the electrostatic force and the restoring force of the mobile contact is present. Then, the dynamic process of contact closure is explicitly calculated with the numerical method. Finally, the effects of spring rigidness and open voltage on the unstable electrical contact behaviors are investigated experimentally and theoretically. This paper highlights that in MEMS systems switch, minimal actuation velocity is required to prevent mechanical bounce and excessive wear

Spin structure factor and thermodynamics in the antiferromagnetic quantum Ising model in the pyrochlore lattice

We numerically compute the temperature dependence of spin structure factor and thermodynamic quantities in the antiferromagnetic quantum Ising model in the pyrochlore lattice. This model exhibits spin disorder ground state with exponentially-decayed spin correlation. We reproduce the temperature dependence of the pinch point structure in the neutron scattering experiment and correct entropy obtained from the measurement of the specific heat.Comment: 6 pages, 7 figure

9-[4-Hydr­oxy-3-(hydroxy­meth­yl)but­yl]guanine monohydrate

In the mol­ecular structure of the title compound, also named penciclovir monohydrate, C10H15N5O3·H2O, the 4-hydr­oxy-3-hydroxy­methyl­but-1-yl group is connected to guanine through an N atom of the imidazole ring. Water mol­ecules stabilize the mol­ecular packing by forming O—H⋯O hydrogen bonds. A three-dimensional network is generated via inter­molecular N—H⋯N, N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonding