Materials Literature
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In this work, which is a follow-up of others, the evolution of structural features of enriched fraction (attacked-hydrated cement) is studied by DRX, extracted from one of the mortar prisms (1:3) of 1 X 1 X 6 cm of the various series of test specimens made with a portland cement resistant to sulfate (cement 2) and wit…
In the present report the author, as the Spanish representative member in the meetings of the Europe-Asia-Afriqua Scientific Committee organizing the 8th International Congress on the Chemistry of Cements, which sponsored by Brazil will take place in Rio de Janeiro, July 1986, describes the course of the second commit…
ADVERTISEMENT RETURN TO ISSUEPREVArticleIon exchange and dehydration of layered [sodium and potassium] titanates, Na2Ti3O7 and K2Ti4O9H. Izawa, S. Kikkawa, and M. KoizumiCite this: J. Phys. Chem. 1982, 86, 25, 5023–5026Publication Date (Print):December 1, 1982Publication History Published online1 May 2002Published ini…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotophysical and redox properties of water-soluble porphyrins in aqueous mediaK. Kalyanasundaram and M. Neumann-SpallartCite this: J. Phys. Chem. 1982, 86, 26, 5163–5169Publication Date (Print):December 1, 1982Publication History Published online1 May 2002Published inissue…
The mathematical functions necessary for Rietveld refinement of time-of-flight neutron powder diffraction patterns from spallation sources are developed and a computer program for least-squares analysis is described. The results of Rietveld refinements of nickel and a low-carbon steel are described and discussed. The…
The stability of tetragonal ZrO 2 particles in ceramic matrices was considered, with particular reference to Al 2 O 3 ‐ZrO 2 composites and to partially stabilized ZrO 2 . In both systems, particles above a “critical” size transform martensitically to monoclinic symmetry on cooling to room temperature. The critical fa…
This outstanding volume has managed the nearly impossible task of combining the expertise of all six authors in a lucid and homogeneous style of writing. Subtitled ‘A Text for Biologists, Material Scientists and Geologists,’ the book has evolved from a short course taught each summer at Lehigh University. The book pro…
The general conditions for a superposition model of spin Hamiltonian parameters to exist are investigated with special reference to the ground state splitting of Cr 3+ in ruby.
Abstract The ionic conductivity of polyoxyethylene‐ and polyoxypropylene‐polyurethane networks containing sodium tetraphenylborate was studied as a function of temperature and salt concentration. The results can be rationalised in terms of free volume considerations. The fact that the WLF equation applies to the condu…
The pressure, temperature, and frequency dependence of the dielectric properties of a single crystal of Sr0.6Ba0.4Nb2O6 are measured across its c-axis. A linear relationship of the Curie temperature (Tc) with pressure (p) is observed with dTcdp = −6.8 K/kbar. The transition is interpreted in terms of the displacement…
Deposition and study of calcium films were achieved under ultrahigh vacuum. The latter was obtained with the use of an ion pump and a helium cryopump. The temperature of the substrate ranged between 90 and 400 K. The electrical resistance was measured with the use of a four-probe method with a constant current. Film t…
Four different open chain forms of methanol dimer have been identified in nitrogen matrices through temperature and IR irradiation effects. Each form is characterized by two OH stretching vibration frequencies, one (D1) close to the monomer frequency (3664 cm−1) and corresponding to the oxygen perturbed (electron dono…
We assess the importance of the impurity states of a doped trans-polyacetylene chain. The impurity potential is modeled by a point charge that is located off the chain and is screened phenomenologically. The common assumption that the dopant levels of a dimerized chain closely approximate the hydrogenic levels of a po…
The real and imaginary parts of the complex dielectric permittivity of the supercooled smectic G phase of N-(4′-n-pentyloxybenzylidene)-4-n-butylaniline have been measured from 50 Hz to 200 kHz and 77 to 260 K. The glass transition temperature of the smectic phase is 181 K. Two relaxation regions were observed; one ab…
Ab initio self-consistent-field---linear combination of atomic orbitals---molecular-orbitals calculations on undoped and lithium-doped $p$-quaterphenyl, a model chain for poly-($p$-phenylene), demonstrate dramatic changes in geometrical and electronic structures upon doping. For a charge transfer of less than $0.1e$ p…
The elastic reflectance spectra for low-energy electrons (0-30 eV) of fcc metals show characteristic structure related to critical points in the energy bands. The (111) surfaces of Au, Ag, Pd, Cu, Ni, and Al have been investigated and all have spectra consisting of a sharp reflectance peak followed by a broad, more in…
The refractive index of a layer is a sensitive function of the preparation conditions. Normal incidence measurement of the optical properties can reveal possible inhomogeneity of index. We propose a method of automatic determination of the complex refractive index and thickness of a layer which includes systematic mea…
X-ray-photoemission spectra of monoclinic, trigonal, and amorphous selenium have been first measured with the same photoelectron spectrometer in order to directly compare the valence electronic states of the three allotropes of selenium. It has been found that the $4p$ lone pair and the $4s$ band of monoclinic seleniu…
We present a new study of the surface-plasmon contribution to surface-enhanced Raman scattering from molecules adsorbed onto metallic gratings. To this end, we use a rigorous electromagnetic theory of diffraction, i.e., a theory in which the groove depth is not considered as a perturbative parameter. The rigorous feat…
Using a natural type IIb diamond, which is p-type semiconducting, as a substrate material, and implanting this diamond with carbon ions to induce n-type regions, diode and bipolar transistor action could be obtained. Owing to the geometrical positions of the collector, base, and emitter, which in this case were latera…