Materials Literature
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An electronic (metal-to-insulator) phase transition of the first order, which can be caused by an external magnetic field, was discovered in Nd 1/2 Sr 1/2 MnO 3 . A clear hysteresis was observed during the increase and decrease of an external magnetic field at a fixed temperature. The hysteretic field region was obser…
The structures of an isolated CAl12 cluster and a solid composed of CAl12 clusters have been studied using the Car–Parrinello method, based on the density functional theory and the local density approximation. We have compared the results of using the ultrasoft Vanderbilt pseudopotential with those of both a tradition…
The generalized hydrodynamics equations, including nonlocal behavior in time, are used to calculate density response functions for impulsive stimulated light scattering (ISS) from glass-forming liquids. Single-exponential relaxation dynamics are considered first, and then the results are generalized to account for com…
Impulsive stimulated light scattering was used to investigate structural relaxation dynamics of the organic glass-former salol. Relaxation dynamics on ns–ms time scales are monitored in the 238.7–280.5 K temperature range and found to be described well by the Kohlrausch–Williams–Watts relaxation function. The nonergod…
The one- and two-photon optical absorption spectra as well as the frequency dependent third-harmonic generation response of a side-chain polymer containing 4-dialkylamino- 4′-nitro-stilbene (DANS) as its side group have been measured over a wide range of frequency. A three-state model, based on an intermediate neglect…
This paper examines the three well-known empiricisms that accompany the glass transition of fragile glass-forming liquids: the unusual thermodynamic behavior of supercooled liquids that is usually called the Kauzmann paradox, the temperature dependence of the relaxation time as embodied in the Vogel–Fulcher law, and t…
The potentially pathological example of LaO has been chosen to test the application of ligand field theory (LFT) to metal monoxides. The test consists of a comparison of closed-shell ligand LFT (CSLLFT) results (in which a 2+/2− ionic M2+O2− model is a priori postulated with a point-charge ligand) against ab initio mu…
Abstract We extend the CLM theorem (Cherkaev, Lurie & Milton, Proc. R. Soc. Lond. A (1992) 438, 519-529) to planar linear elastic materials of Cosserat (micropolar) type, that is those having microrotation as an additional degree of freedom besides the two in-plane displacements. More specifically, it is shown tha…
Reactions of nickel (Ni−n, n=3–10), palladium (Pd−n, n=3–8), and platinum (Pt−n, n=3–7) cluster anions are investigated in a flow tube reactor. Rate coefficients are measured for reactions with N2, O2, CO2, and N2O. Reactions with O2, CO2, and N2O have rates that are greater than 10% of the collision rate for most clu…
Surfaces eroded by ion-sputtering are sometimes observed to develop morphologies which are either ripple (periodic), or rough (non-periodic). We introduce a discrete stochastic model that allows us to interpret these experimental observations within a unified framework. We find that a periodic ripple morphology charac…
Abstract Mechanical and rheological properties of blends of polypropylene (PP) and linear polyethylene (PE) were studied, with particular attention to the effects of aging of such mixtures. These two olefin polymers are basically incompatible. In PP‐rich blends, addition of highdensity PE (HDPE) causes only a slight d…
The crystal structure of the Glu-105-->Gly mutant of catabolic ornithine transcarbamoylase (OTCase; carbamoyl phosphate + L-ornithine = orthophosphate + L-citrulline, EC 2.1.3.3) from Pseudomonas aeruginosa has been determined at 3.0-A resolution. This mutant is blocked in the active R (relaxed) state. The structure w…
Surface plasmon dispersion on Pd(110) was investigated along the high-symmetry directions (110) and (001) with angle-resolved electron-energy-loss spectroscopy. A large negative initial dispersion with transferred momentum is found in spite of the strong shift of plasmon and surface plasmon frequencies induced by the…
The temperature dependence of the yield stress of diamond is predicted from existing data of crystals with diamond or diamondlike structure: silicon, germanium, and silicon carbide.Received 1 June 1995DOI:https://doi.org/10.1103/PhysRevLett.75.3470©1995 American Physical Society
We report pressure-dependent optical studies for different sized CdS x Se 1-x nanocrystals embedded in a glass matrix. The increase in the phase stability in going from wurtzite to rock salt structure is reversible and size dependent. Different possible sources such as strain from defects, semiconductor-to-glass-matri…
We report the effect of hydrostatic pressure up to 8 kbar on magnetoelastic, magnetic, and transport properties in the temperature range 10–300 K. An increase of Curie temperature Tc with pressure ΔTc/Δp=2.6 K/kbar was determined from ac susceptibility measurements. The anomalies in resistivity and magnetovolume effec…
The valence band offsets at the heterointerfaces of the CdF2/CaF2/Si(111) structure grown by molecular beam epitaxy were evaluated using x-ray photoelectron spectroscopy, and the energy band diagram of this heterostructure was proposed. It was found that the interface of CdF2/CaF2 has large conduction band offset: 2.9…
Crystallization of a suspension of hard spherical polymer particles is measured by following the evolution of the main Bragg reflection from the close-packed planes. Crystal growth, evident below the melting concentration, is effectively suppressed at higher concentrations due to superlinear rates of crystal addition.…
Unlike conventional crystals, quasicrystals are predicted to be elastically isotropic. To confirm this prediction experimentally, one must distinguish the quasicrystal from nearly isotropic crystals, which requires a high degree of precision. We report the use of resonant ultrasound spectroscopy to determine that the…
Carbon nitride thin films have been successfully grown on nickel substrates by a novel arc-plasma jet chemical vapor deposition. These films were characterized by Auger electron spectroscopy, transmission electron microscopy, and Raman spectroscopy. Small grains (∼0.1 μm) as well as nanocrystallites found in the films…