Materials Literature
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The impact ionization coefficients for electrons and holes in both (100)- and (111)-oriented Si have been determined from photocurrent measurements performed on reach-through avalanche photodiodes. The results for both orientations are similar, indicating that the ionization coefficients are isotropic. Monte Carlo cal…
Several microwave absorbers have been characterized in terms of transmittance and reflectance at frequencies between 35 GHz and 3 THz. The materials studied were a series of iron-loaded cast epoxy absorbers known as Eccosorb. Measurements show that reflectance and absorption coefficient increase with the iron density.…
Physical properties of the CDW state of 1 T -TiSe 2 such as electronic band structures are investigated on the basis of the band-type Jahn-Teller model by extending our microscopic theory of lattice instability in the normal phase. The results are summarized as follows: (i) The triple- q CDW state is more stable than…
The first measurements are reported of frequency-dependent (ac) conductivity in thin films of amorphous phosphorus prepared by rf sputtering. The behavior of the ac conductivity \ensuremath{\sigma}(\ensuremath{\omega}) is broadly similar to that which has been observed previously in many other types of amorphous semic…
The electronic structure of \ensuremath{\alpha}-quartz and a-${\mathrm{SiO}}_{2}$ has been calculated using the tight-binding recursion method. For a-${\mathrm{SiO}}_{2}$ two structural models were used. The first one consisted of the continuous-random-network model constructed by Bell and Dean (BD). The second model…
1H NMR solid state techniques have been used to study bonding properties, location, and mobility of hydrogen in various phases of the hydrogen bronze HxMoO3. Temperature-dependent spectra characteristic of different degrees of intercalation have been observed, and furthermore, from measurements of the relaxation rate,…
The dielectric theory of electron-energy-loss spectroscopy (EELS) in the reflection geometry is reformulated so as to allow for an arbitrary compositional variation of the target material in the direction perpendicular to its surface. A new, general expression for the energy-loss spectrum is obtained in terms of an ex…
The energy dispersion of conduction (or unoccupied) bands of graphite has been studied by angle-resolved ultraviolet photoelectron spectroscopy. Photoemission peaks originating in the conduction bands were successfully separated from those of the valence bands by comparing two sets of angle-resolved ultraviolet photoe…
The increase in the current that flows in a negative point-to-plane corona discharge when a porous layer is present on the plane was studied by using a fast storage oscilloscope. It was found that the current increase is due primarily to an increase in the frequency of the Trichel pulses at the cathode, and less than…
Absorption and cathodoluminescence spectra have been obtained from synthetic diamonds which have been heated at temperatures between 1700 and 2400 degrees C to produce various degrees of nitrogen aggregation. At the lower temperatures a number of optical centres attributed to nitrogen in intermediate stages of aggrega…
During the impact of an elastic sphere on an elastic, massive, substrate some of the kinetic energy is radiated into the massive substrate as elastic waves and is not available for subsequent recovery as kinetic energy. This loss of recoverable energy then determines the maximum possible value for the coefficient of r…
Thomas R. Loughlin, Michael A. Perez; Mesoplodon stejnegeri, Mammalian Species, Issue 250, 13 December 1985, Pages 1–6, https://doi.org/10.2307/3503801
The principle radiation damage effects occurring in optical materials, particularly those produced by energetic particles and gamma rays, are described phenomenologically. Included is a description of the basic processes whereby radiation interacts with non-metals. Emphasized are: 1) ionization induced electron and ho…
The optical properties of fiber waveguides can be degraded by exposure to nuclear radiation, primarily through the generation of color centers in the fiber core. This paper will review recent studies of the radiation-induced absorption in state-of-the-art fiber optics. Particular emphasis is placed on the development…
The natures of radiation-induced defects and defect generation processes in optical glasses are critically reviewed. Materials of interest here include silica, silicates, and fluorides, hence encompassing glasses now in use or contemplated for fiber optics, lenses, mirrors, windows, and other optical applications. The…
The tracer diffusion coefficient is investigated for a correlated diffusion of a tracer, which is a particle of the lattice gas. The lattice gas consists of particles of arbitrary concentration hopping on a two-dimensional honeycomb lattice, which interact only as repulsing point hard cores. Exchange between different…
The low-temperature ferroelectric-paraelectric phase transition occurring in lead scandium tantalate (PbSc 1 2/Ta 1 2/O 3 ) has been investigated by X-ray diffraction. The symmetry of the low-temperature phase is shown to be rhombohedral and the lattice parameters are given over the temperature range 30-300K. The atom…
The phase behavior of multicomponent polymeric materials is a crucial factor in determining their physical properties and subsequently their utility. For systems forming separate phases, the important issues are phase morphology (size and shape) and the nature of the interface (wetting and adhesion) between phases. Fo…
This report was produced by a scientific committee of eight members, chaired by Richard C. McCall. It is a reference manual dealing with the problem of neutron production that results from the operation of high-energy electron linear accelerators used in radiation therapy. As radiation therapy becomes more sophisticat…
A model for the paramagnetic ${E}_{2}^{\ensuremath{'}}$ center in alpha quartz is tested by means of semiempirical molecular-orbital calculations. The ${E}_{2}^{\ensuremath{'}}$ center is proposed to be a variant of the ${E}_{4}^{\ensuremath{'}}$ center (a hydrogen atom substituted for an oxygen atom) with one silicon…