Materials Literature
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Abstract A new technique was developed to study the molecular mechanics of highly oriented polypropylene during stress relaxation and creep. The polarized infrared spectrum was recorded while the polymer was under load. Stress relaxation effects were investigated during the two‐stage process of fast decay followed by…
The theory of the holographic grating is applied to the design of aberration-corrected holographic concave gratings for use with Seya–Namioka monochromators. A method of determining the proper recording parameters is described. The performance of gratings that would be produced by use of the proper recording parameter…
The bulk magnetic susceptibilities of several synthetic polypeptides have been measured. The observed anisotropy of the diamagnetic susceptibility Δχ for oriented nematic liquid crystals of poly-γ-benzyl-L-glutamate (PBLG) in dichloromethane is 7.0±0.7×10−6 emu/mole. For a PBLG axial ratio of 150, a value of the twist…
Optical-reflection spectra have been measured for hexagonal NiS in the energy range 0.01 - 5.0 eV at temperatures both above and below the metal-nonmetal transition near 260 K. Using Kramers-Kronig analysis it is found that the conductivity below 0.1 eV drops on cooling through the transition. Above this energy a peak…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReversible reaction of simple ferrous porphyrins with molecular oxygen at low temperaturesDavid L. Anderson, Charles J. Weschler, and Fred BasoloCite this: J. Am. Chem. Soc. 1974, 96, 17, 5599–5600Publication Date (Print):August 1, 1974Publication History Published online1 M…
The design features of an efficient geometric backscattered electron detector are presented. This detector appears to have approximately the same limit of spatial detectability as a secondary electron detector. It has the advantages over a secondary electron detector of a reduction of charging artefacts, improved flat…
A method of tracing rays through holographic gratings, both plane and concave, is developed. The method is applicable not only to holographic gratings, but also to mechanically ruled gratings with variable spacing and curved grooves. Some examples are given in the form of spot diagrams for certain specific cases. A mo…
Superposition of illumination with white light on thermal treatments of amorphous films, formed by deposition of high-purity Se on mica, had the following effects on crystallization: (i) interface cylindrites thickened much more rapidly but their radial growth rates were not detectably changed; (ii) the number density…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure of sodium gold(I) thiosulfate dihydrate, Na3Au(S2O3)2.2H2OHelena. Ruben, Allan. Zalkin, Marjorie O. Faltens, and David H. TempletonCite this: Inorg. Chem. 1974, 13, 8, 1836–1839Publication Date (Print):August 1, 1974Publication History Published online1 May…
By empirical methods similar to those outlined previously for the iron garnets, molecular-field coefficients are reported for the complicated LiTiZn ferrite system. As in the case of the garnets, the intrasublattice coefficients NAA and NBB are linearly dependent on the Ti4+ and Zn2+ concentrations, but the intersubla…
The crystal structures of 4 ammonium exchanged, heat-treated faujasites were determined from x-ray powder data. Structure I, often called "decationated Y," has lost 15 framework aluminum atoms and 21 framework O (1) atoms (bridging oxygen atoms) per unit cell, and 15 Al(OH) 2 + ions are present in the sodalite cages.…
This paper reports a new phenomenological observation regarding the stress crazing of glassy polystyrene. It was found that the applied stress to initiate a craze, often called the critical crazing stress, is independent of molecular weight. Further, the gross structure of the craze does depend on molecular weight, an…
We present dc measurements of the reversible pyroelectric effect in the temperature interval 170–350 °K and of the inverse piezoelectric effect at 0.3 °K for films of commercial polyvinylidene fluoride which were polarized in a strong dc electric field at elevated temperatures. The pyroelectric coefficient dP/dT incre…
The magnetic structure of high-purity single crystals of erbium has been studied by neutron-diffraction techniques. Although the general characteristics of the magnetic structure of erbium have been found to be in agreement with earlier measurements, several interesting new features have been observed. At 84.4 \ifmmod…
The main objective of this work is the study of corrosion behavior under heat transfer conditions, i.e., in the presence of temperature gradients. Quantitative assessment of this factor necessitated performing complementary experiments to investigate the kinetics of the corrosion process and develop a mathematical rat…
Abstract Using Kubo's formula the optical intraband absorption is studied in two models of disordered systems. The model A is characterized by some few types of atoms and by strong electron‐phonon interaction, the model B by a continuous distribution of atomic levels and by an arbitrary strength of the electron‐phonon…
Summary The phylogeny of eucaryotic algae can be best illustrated by establishing lines of algal evolution leading from simple unicells to an elaborated tissue thallus. These evolutionary lines of algal morphological progress represent the Classes. The single grades of algal advance in a class represent a lower taxono…
The new compounds CaCuSb(Bi) and SrCuSb(Bi) were prepared and their structures determined. They crystallize in the „filled“ NiAs-(Ni,In)-structure.
Abstract Local vibrational modes of boron impurities have been detected in single crystals of Y 3 Fe 5 O 12 , Gd 3 Fe 5 O 12 , Y 3 Ga 5 O 12 , and Gd 3 Ga 5 O 12 , which were grown from a melt containing B 2 O 3 flux. The B 3+ ion is incorporated on a heavily distorted defect site, in threefold oxygen coordination. Fr…
The previously reported synthesis of ferrous ferricyanide involved pyrolysis of Prussian Blue which contained both the soluble KFeFe(CN)6 and the insoluble Fe4 [Fe(CN)6]3 forms. The soluble and insoluble Prussian Blues, and the ferrous ferricyanide compounds which derive from this vacuum pyrolysis at 300–500°C, have b…