In this paper we present an X-ray image deprojection analysis of EINSTEIN OBSERVATORY imaging data on 207 clusters of galaxies. The resulting radial profiles for luminosity, temperature , and electron density variations are determined from the cluster surface-brightness profiles according to gravitational potential constraints from average X-ray temperatures and optical velocity dispersions. Th...

We have measured the thermal expansion and the temperature dependence of z and y components of the refractive index for KTiOPO4 and KTiOAsO4, in the wavelength range 532-1585 nm and temperature range 25-200 degrees C, using an interferometric technique. The measurements were used to derive temperature-dependent Sellmeier equations for the two materials. These equations predict with good agreeme...

Differential group delay measurements of a fiber-based dispersion compensation module under different controlled temperature variations experience long birefringence relaxation times (>10  h) in response to temperature changes. These are interpreted here qualitatively with a stress strain behavioral model based on silica's viscoelastic property.

Redshifts of several galaxies thought to be associated with NGC 326 are determined. The results confirm the presence of a cluster and find a mean redshift of z = 0.0477 ± 0.0007 and a line-of-sight velocity dispersion σ z = 599 (+230, −110) km s −1. The velocity dispersion and previously measured X-ray gas temperature of kT ≃ 1.9 keV are consistent with the cluster σ z /kT relation, and NGC 326...

We investigate experimentally the lifetime of the photons in a cavity containing a medium exhibiting strong positive dispersion. This intracavity positive dispersion is provided by a metastable helium gas at room temperature in the electromagnetically induced transparency regime, in which light propagates at a group velocity of the order of 10⁴ m·s⁻¹. The results definitely prove that the lifet...

We study the behavior of the pion dispersion relation in a pion medium at finite density and temperature, introducing a chemical potential to describe the finite pion number density. Such description is particularly important during the hadronic phase of a relativistic heavy-ion collision, between chemical and thermal freeze-out, where the pion number changing processes, driven by the strong in...

Dispersion relations of the s–p derived surface state on (111) surfaces of silver and copper have been measured using low-temperature scanning tunneling microscopy and spectroscopy. For silver as well as for copper we find a significant deviation from a parabolic dispersion characteristic of free-electron-like systems. A simple tight-binding model accounts for the trends in the measured dispers...

We calculate the finite temperature self-energy for neutrinos in the presence of a constant magnetic field in a medium in the unbroken SU(2) ⊗ U(1) model. We obtain the exact dispersion relation for such neutrinos and find that the thermal effective mass is modified by the magnetic field. We also find a simple analytic expression for the dispersion relation and obtain the index of refraction fo...

We report an ultrasound exfoliation of graphite in a weakly basic solution to produce multi-layer graphene dispersion. A unique feature of this process is that no surfactant was added to stabilize the exfoliated graphene in water. The concentration of the graphene dispersion prepared by this approach can be up to 0.02 mg mL(-1) and it was stable at room temperature for several months.