Materials Literature
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Abstract Pressure‐volume‐temperature measurements were performed on five amorphous thermoplastics. From these data, first derivatives of internal energy with respect to volume were calculated. These derivatives were cast into the Lennard‐Jones form and the two defining parameters were evaluated for each polymer. It wa…
Computational predictions, based upon conventional one-dimensional tunneling theory, are presented for charge and energy transport by electron tunneling thermoelectric effect. It is shown that a temperature difference across a tunnel junction connected in an open electrical circuit produces a thermopower S and a heat…
Abstract Soft‐segment molecular weight, soft‐segment crystallization, hard‐segment‐type, and reactive diluent level were examined in urea and urethane acrylates. Increasing soft‐segment molecular weight led to a decreased tensile modulus, increased strength, and increased elongation at break. Soft‐segment crystallizat…
The satellite structures of 3s core-level photoemission spectra of Mn and Fe dihalides and mono-oxides have been studied systematically. We found that exchange splitting between 3s holes and 3d electrons, intrashell electron correlation, and final-state screening (charge-transfer satellite) effects all contribute to t…
Parallel-detection electron energy loss spectroscopy (EELS) combined with scanning transmission electron microscopy (STEM) and a field emission source provides an unprecedented sensitivity for elemental microanalysis. By deflecting the energy loss spectrum across a parallel detector and computing the difference spectr…
A theory of collective translational vibrations of 90° domain walls (DWs) in ferroelectric ceramics is presented. Vibrational motions of DWs forming a regular domain structure of a representative grain are assumed to be completely correlated but independent of DW oscillations in other grains. A dynamic mechanical stre…
The validity of nonmagnetic grain-boundary (NMGB) models for the initial permeability of polycrystalline ferrites is examined. The domain size in a series of wet-chemically prepared polycrystalline MnZn ferrites, in the demagnetized state, has been determined by neutron depolarization. A transition in the intragranula…
We present the eigenpolarization states of a commercially available liquid-crystal television display and show that phase-only modulation can be achieved over a large dynamic range of video voltages for several bias voltage settings if the eigenpolarization states are used. A set of operating curves using these polari…
Despite the rapid progress being made in the synthesis of diamond films and recent interest in polishing of diamond films, no systematic measurements of friction and wear on polished diamond films have been reported. In the present study, chemomechanical and laser polishing techniques are used, and friction and wear d…
Chemical-vapor deposition of diamond on transition-metal substrates of Cu, Ni, Fe, and their alloys NiAl, Ni3Al, FeSi2, and FeSi has been investigated. It is shown that diamond grows easily on Cu with a very small amount of graphite, while on Ni and Fe there is rapid growth of the graphite layer before diamond deposit…
An elongated toroidal cage form of graphitic carbon ${\mathrm{C}}_{240}$ that has an elliptical cross section is proposed. The elongated toroidal form consists of pairs of pentagons and heptagons among the hexagons of carbon atoms. The rotational symmetry, the cohesive energies, and thermal stabilities of the elongate…
Abstract Effective thermal conductivities of powder‐filled epoxy composites were experimentally obtained using a transient method. Fillers used were aluminum and cupric oxide. Comparisons of these data with published correlations indicate that Agari's model can give better fits. Nielsen's model may also give a good pr…
Third-order nonlinear optical properties of As2S3 chalcogenide bulk glass are studied experimentally. Third-harmonic generation (THG) measurement shows the value of the third-order susceptibility χ(3) to be 5.6×10−19 m2/V2 (1.0×10−11 esu) at the funda- mental-light wavelength of 2.1 μm. This value is more than 300 tim…
The temperature dependences of the fluorescence lifetimes of ${\mathrm{Cr}}^{3+}$ doped insulating crystals, which have been used as temperature-sensing elements or have such potential uses for different temperature regions, are reviewed in terms of the crystal-field strength. Two single configurational coordinate mod…
A recently introduced bead-spring type model of polymer chains with purely repulsive interactions between the beads is modified to allow for attractive forces at intermediate distances. This new model is suitable for the study of thermal properties of three-dimensional polymer solutions and melts and can be efficientl…
Using Raman and infrared transmission spectroscopy, the vibrational properties of siloxene (${\mathrm{Si}}_{6}$${\mathrm{O}}_{3}$${\mathrm{H}}_{6}$) and its derivatives are investigated and interpreted in terms of various structural modifications of siloxene which have been proposed in the past. On the basis of experi…
We have solved the structure of a chorismate mutase (chorismate pyruvatemutase, EC 5.4.99.5), the 1.9-A crystal structure of the monofunctional enzyme from Bacillus subtilis. The structure determination process was an unusual one, involving 12 monomers of the enzyme in the asymmetric unit. This structure was solved by…
The crystal structure of the serine protease subtilisin Carlsberg in anhydrous acetonitrile was determined at 2.3 A resolution. It was found to be essentially identical to the three-dimensional structure of the enzyme in water; the differences observed were smaller than those between two independently determined struc…
The total energy of ZnO as a function of unit cell volume has been calculated for the zinc-blende, wurtzite, and rocksalt structures by the ab initio all-electron periodic Hartree-Fock linear-combination-of-atomic-orbitals method using a large Gaussian basis set that was variationally optimized for the solid state. Ex…
Mechanisms of thermoluminescence (TL) in aragonite have been studied using electron spin resonance (ESR) techniques. Natural aragonite shows a prominent TL glow peak at 613 K. Additional gamma irradiation enhanced this glow peak but displaces it slightly to 593 K, and induces two glow peaks at 393 and 493 K. Pre-annea…