Materials Literature
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We discuss how concepts from rigidity percolation can be used to understand the low-frequency excitations and elastic properties of network glasses like ${\mathrm{Ge}}_{\mathrm{x}}$${\mathrm{As}}_{\mathrm{y}}$${\mathrm{Se}}_{1\mathrm{\ensuremath{-}}\mathrm{x}\mathrm{\ensuremath{-}}\mathrm{y}}$. When the mean coordinat…
Two stable conformations, a planar or nearly planar rod and a coil, have been located on the potential-energy surfaces of several conducting polymers: polythiophene (PT), poly(3-methylthiophene) (PMeT), polypyrrole (PPy), and poly(3-methylpyrrole) (PMePy). The planar structure is slightly more stable for PT, PPy, and…
Taking into account recent developments and present trends in devices and component technologies, the future development of electrically addressed liquid crystal spatial light modulators is considered. In particular, the combination of single-crystal-silicon active backplane and chiral smectic C liquid crystal technol…
Absorption spectra of ${\mathrm{Tm}}^{3+}$:${\mathrm{Y}}_{3}$${\mathrm{Al}}_{5}$${\mathrm{O}}_{12}$ are reported between 1.9 and 0.26 \ensuremath{\mu}m at 15 and 90 K, and between 0.80 and 0.35 \ensuremath{\mu}m at 1.6 K. Laser-excited emission obtained at 80 K is also reported from the ${\mathrm{Tm}}^{3+}$ manifolds…
Raman scattering experiments from a polycrystalline sample of black phosphorus were done with a diamond-anvil cell from 0.25 to 11.6 GPa at a temperature of 15 K. Three Raman-active modes in the A11 orthorhombic (Cmca) phase were observed as a function of pressure to approximately 7.7 GPa, the point where black phosph…
Molecular dynamics and the embedded-atom method (EAM) have been applied to the study of intergranular hydrogen embrittlement in Ni-based alloys. A new technique was developed for constructing EAM functions from experimental data on binary systems. The technique allows one to express experimental quantities of the bina…
We analyze delayed conduction in three recent models of switching charge-density waves. Each model predicts a power-law dependence of switching delay near threshold: \ensuremath{\tau}\ensuremath{\sim}${\ensuremath{\varepsilon}}^{\mathrm{\ensuremath{-}}\ensuremath{\beta}}$, where \ensuremath{\tau} is the delay and \ens…
The crystallization behavior of evaporated TiO2-SiO2 mixed composition films and its dependence on composition, temperature, time and type of mixing (codeposited or alternating layers) were studied. All codeposited films annealed between 600 and 900 °C with 15%–90% molar TiO2 exhibited crystallization in the anatase p…
Surface-plasmon resonances of silver microparticle aerosols have been measured as a function of average particle size. Resonance line shapes are modeled as a function of particle size and complex refractive index. The surface-plasmon frequency is found to exhibit a red shift from 3.8 to 3.4 eV as the average particle…
The use of thin foils to investigate the propagation of a combustion wave has been demonstrated for the nickel-aluminum system. The initiation of a reaction wave in the foils was found to be triggered by the melting of nickel regardless of the composition of the foil ensemble. In contrast, the propagation rate decreas…
We have established for alkali ions in oxide glasses a strong correlation between the fractional (Kohlrausch) exponent \ensuremath{\beta} in the conductivity relaxation function, exp[-(t/${\ensuremath{\tau}}^{\mathrm{*}}$${)}^{\ensuremath{\beta}}$], and the activation energy ${E}_{a}^{\mathrm{*}}$ of ${\ensuremath{\ta…
The authors present a numerical calculation of the edge capacitance corrections for thin unguarded disc electrodes placed on opposite faces of a dielectric sheet or film. As a function of the ratio (a/h) of electrode radius to sample thickness, the correction grows logarithmically for small values of the sample dielec…
The Archaebacterium Thermoplasma acidophilum has a histone-like protein (HTa) abundantly associated with its deoxyribonucleic acid. Each native tetrameric complex of HTa contains 20 phenylalanine residues, 4 tyrosine residues, and no tryptophan. When the protein was excited by radiation at 252 nm, which is a wavelengt…
Polarisation currents were investigated in polycrystalline BaTiO 3 in order to investigate its I-V characteristics. All but one of the measurements were performed at temperatures below the Curie point, for voltages between 1 V and 1000 V. The experimental curves consist of three parts of different shape: a region in w…
Kinetics parameters of BeO thermoluminescent material are presented. Thermoluminescence emission from irradiated BeO shows two well separated peaks. Using a linear heating rate of 8.07 K s -1 , the peak temperatures at maximum are 495 and 642 K respectively. Various methods have been used for trap parameter determinat…
A study has been made of the electrochromic behaviour of polyaniline films of potential use in passive display devices, and a preliminary examination of the properties of substituted polyanilines has also been carried out. Films of 'emeraldine-type' conducting polyanilines have been grown electrochemically from aqueou…
The one-dimensional, discrete Schrodinger equation is studied analytically for a class of quasiperiodic Hamiltonians known as the copper mean. The lattice is described by a recursion formula S L+1 =S L-1 S L-1 S L , L=2,3, . . ., given the two initial sequences S 0 and S 1 . Extended states are shown to exist for ener…
A low-temperature (≊400 °C) plasma-enhanced chemical vapor deposition process has been developed to grow diamond films for optical coatings application. Films with fine grains (≤3000 Å) have been obtained by controlling diamond nucleation. The surface roughness of the films is on the order of 50–200 Å. The optical tra…
Molecular-dynamics computations based on a simple tight-binding interatomic potential fitted to hcp zirconium confirm the Burgers mechanism for the temperature-dependent hcp-bcc phase transition. In our model the transverse ${\mathrm{T}}_{1}$ [110]-bcc N-point phonon, which is involved in the transition, is unstable i…
The properties of bismuth and tellurium microbolometers are presented. The TE devices are shown to have responsivitics approximately 100 times that of the more conventional Bi microbolometers. The Te device impedance is, however, much larger than Bi microbolometers of comparable size. To our knowledge, the Te device h…