Materials Literature
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A pattern of attack, qualitatively similar to groove pitting of irradiated fuel cladding, was produced in the laboratory. The relative susceptibility to attack of X-8001 alloy aluminum in comparison to 1245 alloy aluminum is in agreement with reactor experience. The remaining readily recognizable feature of in-reactor…
Pyrolytic graphite was cleaved in a high vacuum to obtain clean surfaces, and the secondary electron emission properties of these surfaces were determined. Pyrolytic graphite has a maximum secondary emission yield of 1.0 at 300-eV primary electron energy for electrons incident normal to the basal plane. The most proba…
Methods commonly used for reducing or for eliminating image distortion in the electron microscope image frequently cause inconvenience to the operator or are effective only over a limited range of magnification. In the present investigation previous calculations of Liebmann and Haine are extended in order to evaluate…
The solution spectra of tetraethyl ammonium salts of some complex halides of divalent iron, cobalt and nickel over the range 1000–20 000 cm-1 have been obtained. The positions of the various absorption bands can be correlated with transitions within the 3d shell of the metal ion but the relative intensities reveal the…
Abstract The potential, which a silver wire acquires in contact with Ag + ions in concentrated solutions of KCN, was studied potentiometrically. The solubility products or the instability constants of the following reactions have been calculated: equation image Normal potential values corresponding to the preceding eq…
It is shown in detail how the magnetoelectric effect depends quadratically on the spin-orbit interaction. The effect is discussed in Cr2O3 using the spin Hamiltonian for the cases of an applied field parallel and perpendicular to the crystalline c axis.
The intermetallic compound UFe2 is ferromagnetic. A considerable number of magnetization isotherms have been obtained from 200°K down to 4.2°K with applied field up to 14 000 Oe. The Curie temperature has been determined to be 172°K and the Bohr magneton number 1.02 per UFe2 molecule. Several hysteresis loops at diffe…
Abstract The acid‐catalyzed condensation of formaldehyde and aromatic nitrile has been investigated. Methylenebis( p ‐carboxyphenyl)amide was synthesized in 90% yield by the interaction of p ‐cyanobenzoic acid with formaldehyde under the influence of conc. sulfuric acid. Polycondensation of methylenebis( p ‐carboxyphe…
Abstract Urethane polymers comprise one of the most rapidly expanding areas of the organic chemical industry. Polyurethane production, estimated at about 100 million lb in 1960, is expected to rise to 500 million lb in 1965 and to have an ultimate potential in excess of a billion lb. The polymers are used in foams (fl…
Well-defined exchange splittings of the R lines of Cr3+ in Cr2O3 have been observed in absorption at low temperatures. The majority of the transitions originate on the lowest (Ms=−32) component of the A24 (ground) state and terminate on the four (exchange split) components of the two E2 levels. The lines show strong p…
Evidence has been found which suggests the existence of high‐temperature crystalline modifications of both zirconium carbide and tantalum carbide. The high‐temperature inversion in zirconium carbide, indicated by a sharp decrease in spectral emisivity, in electrical resistivity, and in density, was reversible. No perm…
An abrupt magnetic transition in MnSn2 was reported by Kouvel and Hartelius1 about one year ago. The salient features of the magnetic behavior are a smooth susceptibility maximum at 86°K and an almost discontinuous decrease in susceptibility at 73°K. At the suggestion of Kouvel, a neutron diffraction study was made to…
Abstract A study of the ultraviolet absorption spectrum of polyvinyl alcohol (PVA) was made. Spectral examination of the solvolysis products of vinyl acetate and 1‐methoxyvinyl ester copolymers shows unequivocally that the absorption bands in PVA at 225, 280, and 330 mμ are related to carbonyl‐containing structures. T…
The experimental and theoretical effects of magnetocrystalline anisotropy upon the magnetic first-order phase transition in the compound MnAs are here described. A 3°C orientation-dependent difference in the transition temperature is observed near 20 kOe for a single-crystal specimen. Anisotropy measurements using She…
Abstract Styrene has been grafted onto cellulose in the form of cotton linters, cotton cloth, and rayon by ionizing radiation. Styrene was brought into intimate contact with cellulose by extension of the “inclusion” technique of Staudinger and Krässig, and graft copolymers were prepared by exposure to high energy elec…
The magnetization and electrical resistivity of the ordered alloy MnRh were measured during a complete temperature cycle between 4.2° and 700°K. At all temperatures the magnetization is proportional to field. From 700°K down to about 170°K, the susceptibility rises according to a Curie-Weiss relation, χ=C(T−θ)−1, wher…
The thermodynamics of magnetic processes in several compounds undergoing ferro- or ferrimagnetic to antiferromagnetic transitions are studied using critical field-transition temperature data obtained with a miniature-coil, pulsed-field technique. The zero-field transition entropy change in each material is calculated…
The phenomenon of rotatable anisotropy (RA) in Ni–Fe films refers to a reorientation of the easy axis along the direction of a previously saturating magnetic field in a time <1 sec at room temperature. The effect was first unambiguously observed by Lommel and Graham in Ni films and attributed by them to ferroma…
The spatial distribution of the covalent spin density in MnF2 has been obtained from a measurement of the ``forbidden'' magnetic scattering in the nuclear reflections using polarized neutrons. A partial Fourier map of the projected covalent spin on the basal plane was prepared. A model representing the covalent spin b…
Recently the lateral width of the cellulose microfibril has been estimated as 30 A rather than about 150 to 200 A, by extrapolation of data from model shadowing experiments. The difference was attributed to a layer of metal deposited during shadowing. However, direct photographs of the same microfibrils parallel and p…