Properties of hadron and quark matter studied with a molecular dynamics

We study the hadron-quark phase transition in a molecular dynamics (MD) of quark degrees of freedom. The hadron state at low density and temperature, and the deconfined quark state at high density and temperature are observed in our model. We investigate the equations of state and draw the phase-diagram at wide baryon density and temperature range. We also discuss the transport property, e.g. viscosity, of $q\bar{q}$ matter. It is found that the ratio of the shear viscosity to the entropy density is less than one for quark matter.Comment: Poster presentation at Quark Matter 200

Drift instability in the motion of a fluid droplet with a chemically reactive surface driven by Marangoni flow

We theoretically derive the amplitude equations for a self-propelled droplet driven by Marangoni flow. As advective flow driven by surface tension gradient is enhanced, the stationary state becomes unstable and the droplet starts to move. The velocity of the droplet is determined from a cubic nonlinear term in the amplitude equations. The obtained critical point and the characteristic velocity are well supported by numerical simulations.Comment: 9 pages, 4 figure

Twinning Deformation in Magnesium Compressed along the C-Axis(Physics)

Deformation twinnings in magnesium activated on the c-axis compression were investigated by light and electron transmission microscopies. Well-known twin forms of {1013} and {3034} habit planes were confirmed again, but {1013} twins were frequently observed to occur in groups along {3034} or grow from {1013} habit to {3034} habit. Transmission electron microscopic observations revealed that the well-developed {3034} habit twin has the same orientation relationship with the parent crystal as the {1013} twin. From these observations, it is concluded that the well-developed {3034} habit twins are the {1013} twins developed along {3034} planes. A possible mechanism of the habit plane change is described and the relation between the twin and the compression band is discussed

{1122} <1123> Slip System in Magnesium

The slip mode operative in the c-axis compression of magnesium was examined using precisely-oriented single crystals. From recorded stress-strain curves and observations with light and transmission electron microscopes, it was found that (1) the {1122} slip system operates at all temperatures investigated (from room temperature to 500℃), (2) the work hardening rate of this slip system is very high especially below 200℃, (3) the Burgers vector of the dislocation for the slip system is 1/3 , and (4) the dislocation has a strong preference to lie along a basal plane, which means that the edge dislocation is much less mobile than the screw dislocation. The ductility of polycrystalline magnesium is discussed from above observations

A one-dimensional model for theoretical analysis of single molecule experiments

In this paper we compare two polymer stretching experiments. The outcome of both experiments is a force-extension relation. We use a one-dimensional model to show that in general the two quantities are not equal. In certain limits, however, both force-extension relations coincide.Comment: 11 pages, 5 figure

Chamber basis of the Orlik-Solomon algebra and Aomoto complex

We introduce a basis of the Orlik-Solomon algebra labeled by chambers, so called chamber basis. We consider structure constants of the Orlik-Solomon algebra with respect to the chamber basis and prove that these structure constants recover D. Cohen's minimal complex from the Aomoto complex.Comment: 16 page

The Solute Atmosphere Round a Moving Dislocation and its Dragging Stress

Setting an imaginary tetragonal lattice round a dislocation, the concentration change at each lattice point was calculated in a very short time interval from the jump frequencies of solute atoms between the nearest lattice points, considering the interaction between a solute atom and the dislocation. Repeating this calculation with a high-speed computer, the forming process of a solute atmosphere round a moving dislocation and the stress effected on the dislocation by this atmosphere were obtained. This method is for a non-steady state, from which, if required, a steady state can be obtained as the limiting case

Contraction of cross-linked actomyosin bundles

Cross-linked actomyosin bundles retract when severed in vivo by laser ablation, or when isolated from the cell and micromanipulated in vitro in the presence of ATP. We identify the time scale for contraction as a viscoelastic time tau, where the viscosity is due to (internal) protein friction. We obtain an estimate of the order of magnitude of the contraction time tau ~ 10-100 s, consistent with available experimental data for circumferential microfilament bundles and stress fibers. Our results are supported by an exactly solvable, hydrodynamic model of a retracting bundle as a cylinder of isotropic, active matter, from which the order of magnitude of the active stress is estimated.Comment: To be published in Physical Biolog