Materials Literature
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In situ $^{57}\mathrm{Fe}$ M\"ossbauer spectroscopy and x-ray diffraction on ${\mathrm{CaFeO}}_{3}$ (${\mathrm{Fe}}^{4}$:${\mathit{t}}_{2}^{3}$${\mathit{e}}^{1}$) under pressure have revealed a first-order high-spin (S=2) to low-spin (S=1) transition near 30 GPa. The spin and structure transition is an laternative man…
The characteristic time for establishing thermal equilibrium between the lattice and the spin system is 100±80 ps in ferromagnetic gadolinium.Received 29 May 1991DOI:https://doi.org/10.1103/PhysRevLett.67.3314©1991 American Physical Society
Measurements of the first-order Raman spectrum in homoepitaxially grown synthetic diamond for the temperature range of 300 to 1200 K are presented. Similar measurements for natural type IIa diamond for the temperature range of 300 to 2000 K are also given. Both the Stokes and anti-Stokes components are analyzed for th…
En este trabajo se amplía y se comenta la descripción de Chromulina nevadensis P.M. Sánchez. El estudio se realiza en una laguna oligotrófica de alta montaña (La Caldera), próxima a la laguna de Aguas Verdes, donde se obtuvo el material para su descripción original. Igualmente realizamos algunas consideraciones…
The radiation field from an intense reusable source of flash X-rays that delivers a measured peak dose and dose rate of 370+or-60 krad (CaF/sub 2/) and (3.5 +or-0.7)*10/sup 13/ rad (CaF/sub 2/)/s over a useful area of 80 cm/sup 2/ is characterized. CaF/sub 2/:Mn TLDs (thermoluminescent dosimeters), which are used to m…
Experimental solubilities are reported for anthracene in binary mixtures containing ethyl acetate or diethyl adipate with n-hexane, n-heptane, n-octane, cyclohexane, methylcyclohexane and isooctane at 25°C. Results of these measurements, combined with estimates for the excess Gibbs free energies of the binary solvents…
Abstract Raman spectroscopy due to electric fields at surfaces, which manifests itself as surface‐enhanced Raman scattering (SERS) from adsorbate modes, and as electric field‐induced Raman scattering (EFIRS) from substrate modes, is discussed. In SERS experiments with benzene adsorbed on small Ni/SiO 2 and Pt/SiO 2 cl…
In the design of new organic materials with enhanced nonlinear optical activity, it has been predicted that (gamma) , the third order hyperpolarizability (second hyperpolarizability) will not increase indefinitely in a regular fashion as the conjugation length increases. In regular polyenes, for example, (gamma) has b…
Pore behavior as influenced by migration of an abnormal grain boundary was studied. The pore behavior during the discontinuous growth of hot‐pressed spinel (MgAl 2 O 4 ) — whether the pore can move attached to the grain boundary — is particularly governed by the pore size and the matrix grain size. These phenomena can…
Low-temperature internal-friction measurements have been used to study the universal low-energy excitations in glasses before and after crystallization in two glass ceramics, one based on MgO-${\mathrm{Al}}_{2}$${\mathrm{O}}_{3\mathrm{\ensuremath{-}}}$${\mathrm{SiO}}_{2}$ (Corning Code 9606) and one based on ${\mathrm…
We have applied the Judd–Ofelt theory of f–f transition rates to the absorption and fluorescence of americium in a fluorozirconate glass. The intensity parameters calculated from infrared absorption transitions are inconsistent with the absorption and emission rates observed for the 5L6′ state at 19 960 cm−1, but are…
DTA and dielectric measurements for differently ordered and quenched PbIn0.5Nb0.5O3 crystals are presented. Two phase transitions were found in partially ordered PIN, related to antiferroelectric-paraelectric and ferroelectric-paraelectric phase transitions in the ordered and disordered regions respectively.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCorrected densities and revised coefficients for diffusion of various dialkyl phthalate plasticizers in PVCRobson F. Storey, Kenneth A. Mauritz, and Martin L. CarterCite this: Macromolecules 1991, 24, 25, 6784–6785Publication Date (Print):December 1, 1991Publication History…
We present the hydrodynamic and electrohydrodynamic equations for the liquid crystalline smectic CM phase. This phase, which is fluid in the layers, orthogonal and optically biaxial, has recently been found experimentally in polymeric liquid crystals. We compare the macroscopic properties of the CM phase with those of…
Abstract : This study investigated tools and techniques for performing finite element analysis of the MBU-20/P pilot's oxygen mask. The problem which was investigated was the fit of the mask to the face at Positive Pressure Breathing (PPB) pressures. Deformed geometry of the mask and reaction forces on the face were c…
Characteristics of Brown Forest soils developed under different bio-climatic conditions from low to high eleyations in the Kinki District were studied with special reference to their pedogenetic processes. The Brown Forest soils at high elevations were characterized by a lower bulk density, higher capacities to adsorb…
Abstract Small‐angle neutron scattering (SANS) has been used to investigate macromolecular orientation of uniaxially hot‐stretched partially deuterated polystyrene. Principle radii of gyration and degree of eccentricity were measured over a range of hot‐stretch temperatures, strain rates, and external draw ratios (EDR…
Abstract The Upper Cretaceous (Maastrichtian) Whitemud Formation is a potentially commercial kaolin deposit located in southern Saskatchewan and southeastern Alberta. The Whitemud Formation contains a lower kaolinitic sandstone, a middle lignite and carbonaceous shale, and an upper interbedded siltstone and claystone.…
Abstract Novel regular network polyester films were prepared from pyromellitic (X), biphenyltetracarboxylic (U), and 3,3′,4,4′‐benzophenonetetracarboxylic (W) dianhydrides and ethylene glycol (2G). Prepolymers prepared by melt polycondensation were cast from DMF solution and successively post‐polymerized at 260°C for…
The effect of hydrostatic pressure on the optical-absorption edge of type-IIa diamond has been measured at room temperature to 2.3 GPa using a sapphire anvil cell. The absorption edge shifts toward higher energy at a rate of 6.0 meV/GPa, in fair agreement with the first-principles calculations of Fahy et al. [Phys. Re…