Brillouin Scattering Study of Liquid Glass Transition in Lithium Borate Glass

Abstract

We show the existence of a new class of astrophysical objects where the self-gravity of the dust is balanced by the force arising from shielded electric fields on the charged dust. The problem of equilibrium dust clouds is formulated in terms of an equation of hydrostatic force balance together with an equation of state. Because of the dust charge reduction at high dust density, the adiabatic index reduces from two to zero. This gives rise to a mass limit M AS for the maximum dust mass that can be supported against gravitational collapse by these fields. If the total mass M D of the dust in the interstellar cloud exceeds M AS , the dust collapses, while in the case M D < M AS , equilibrium may be achieved. The physics of the mass limit is similar to the Chandrasekhar's mass limit for compact objects, such as white dwarfs and neutron stars.

Glass Transitions and Elastic Properties of Lithium Borate Glasses over a Wide Composition Range Studied by Micro-Brillouin Scattering

“…10,11) The experimental setup of a micro-Brillouin scattering apparatus has been reported elsewhere. 8,9) A unique feature of this system is the combination of a microscope and a Sandercock-type 3 þ 3 pass tandem multipass Fabry-Perot interferometer (FPI). In order to measure not only a transverse acoustic (TA) mode but a longitudinal acoustic (LA) mode, the Brillouin scattering spectra were measured at the right-angle (90 A) scattering geometry as shown in Fig.…”

“…8,9) The present work is a sequel of our previous studies, 7,8) and the composition range of the elastic properties is successfully extended up to x ¼ 52 mol %.…”

Phonons induced by laser pulses for Brillouin scattering measurements

“…1. It was a silica glass specimen (Tosoh ED-h 2 × 2 × 10 mm 3 ). An Al film in contact with one side (2 × 10 mm 2 ) was placed to reflect the probe laser as required for the RIθA geometry.…”

“…On the basis of this phenomenon, Brillouin spectroscopy has been well established. 1,2) With the use of a focused laser beam as a probe, Brillouin spectroscopy enables the noncontact and nondestructive investigation of local mechanical properties of transparent 3,4) and opaque [5][6][7] materials. Brillouin spectroscopy, unlike other techniques, enables the simultaneous measurement of longitudinal and shear wave velocities.…”

Rapid and simultaneous measurement of longitudinal and shear wave velocities by Brillouin scattering from artificially induced phonons

“…This technique enables the simultaneous measurements of longitudinal and shear wave velocities in a microscopic region at hypersonic frequencies [3] [4]. Moreover, the anisotropy of the materials can be measured by in-plane rotation of the sample.…”