Time-resolved spectroscopic measurements behind incident and reflected shock waves in air and xenon

Time-resolved spectra have been obtained behind incident and reflected shock waves in air and xenon at initial pressures of 0.1 and 1.0 torr using a rotating drum spectrograph and the OSU (The Ohio State University) arc-driven shock tube. These spectra were used to determine the qualitative nature of the flow as well as for making estimates of the available test time. The (n+1,n) and (n,n) band spectra of N2(+) (1st negative) were observed in the test gas behind incident shock waves in air at p1=1.0 torr and Us=9-10 km/sec. Behind reflected shock waves in air, the continuum of spectra appeared to cover almost the entire wavelength of 2,500-7,000 A for the shock-heated test gas. For xenon, the spectra for the incident shock wave cases for p1=0.1 torr show an interesting structure in which two intensely bright regions are witnessed in the time direction. The spectra obtained behind reflected shock waves in xenon were also dominated by continuum radiation but included strong absorption spectra due to FeI and FeII from the moment the reflected shock passed and on

Exponents of 2-multiarrangements and multiplicity lattices

We introduce a concept of multiplicity lattices of 2-multiarrangements, determine the combinatorics and geometry of that lattice, and give a criterion and method to construct a basis for derivation modules effectively.Comment: 14 page

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

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

Swimming depth of migrating silver eels Anguilla japonica released at seamounts of the West Mariana Ridge, their estimated spawning sites

Five hormone-treated female Japanese silver eels Anguilla japonica were tagged with ultrasonic transmitters and released by submersible in the West Pacific at seamounts of the West Mariana Ridge, their supposed spawning grounds. Four eels were tracked for 60 to 423 min in the vicinity of the seamounts. They did not settle at the seamounts but swam at a mean speed of 0.37 m s-1 into open water above deep ground. Their mean swimming depth ranged from 81 to 172 m. Experiments suggest that pre-matured A. japonica migrate to their spawning grounds in temperate warm water and at shallow depths

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