Materials Literature
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Abstract This review has attempted to categorize and describe the degree of ozone resistance available both within and among the various elastomers. Some of the factors affecting ozone resistance and means for obtaining ozone-resistant vulcanizates have been discussed. It has been indicated that by judicious selection…
Intermittent and continuous stress relaxation measurements have been utilized to follow the oxidative degradation of vulcanizates of natural rubber, and of synthetically prepared polybutadienes. Vulcanizates were prepared by exposing samples to high-energy electrons. For natural rubber, only oxidative scission reactio…
Lattice parameter‐composition relations are shown in the system α‐Fe 2 O 3 ‐Cr 2 O 3 . This information is of some value in determining the composition of scales developed during the oxidation of alloys based on Fe‐Cr, such as stainless steels.
An x-ray diffraction method is described for the determination of per cent crystallinity in oriented films and fibers of polyethylene terephthalate by using an x-ray diffractometer in association with a scaler counter. Results are presented to show that sample rotation approximately averages out the crystallite orient…
Abstract Mechanical properties and melt viscosity have been measured on anionc polystyrene of narrow molecular weight distribution and thermal polystyrene of broad molecular weight distribution in an attempt to study the effect of molecular weight distribution. Tensile strength and elongation were found to depend upon…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCHARGE TRANSFER LUMINESCENCE OF A RUTHENIUM(II) CHELATEJ. P. Paris and Warren W. BrandtCite this: J. Am. Chem. Soc. 1959, 81, 18, 5001–5002Publication Date (Print):September 1, 1959Publication History Published online1 May 2002Published inissue 1 September 1959https://pubs.a…
We use a model for ferromagnets such that the electrical current is carried by 4s (or 6s) electrons which are assumed to be described in band scheme and the unpaired electrons (3d or 4f) are assumed to be localized on the lattice points. In the temperature region far below the Curie point the spin-disorder in spin ori…
Abstract The nature of banded spherulites was further investigated. The principal material used was a polyester, namely, polytrimethylene glutarate, but use was made also of nonpolymeric materials. A variety of observations on extinction effects with the Universal Stage conclusively confirmed the twisted crystal model…
The resistivity of barium titanate which is usually of the order of 10 9 ∼10 12 ohm-cm, may be remarkably reduced with suitable control in valency. The valency-controlled barium titanate, whose resistivity is of the order of 10∼10 4 ohm-cm at room temperature, shows anomalous positive character in the temperature depe…
UCRL-
A special technique for the accurate measurement of thermal conductivity is discussed. The method involves use of the Peltier heat to maintain a temperature gradient along the specimen. Straightforward measurements allow calculation of the absolute value of the thermoelectric power, thermal conductivity, and electrica…
Abstract The infrared spectrum of uniplanarly oriented valonia cellulose film and the polarized infrared spectra of doubly oriented films of ramie and bacterial cellulose crystallites have been observed in the region from 640 to 1700 cm. −1 . The spectra have been interpreted with the assistance of band assignments in…
Abstract Natrium, Kalium, Rubidium und Caesium können „stufenweise”︁ zwischen die Kohlenstoff‐Schichten des Graphit‐Gitters eingelagert werden. Aus Lösungen der Alkali‐ und höheren Erdalkalimetalle in flüssigem Ammoniak oder organischen Aminen bilden sich mit Graphit Ammoniakate oder Amine von Alkali‐ bzw. Erdalkali‐g…
Common type I diamonds (as classified by Robertson et al.) have additional absorption in the infrared and ultraviolet. It is shown that the strongest absorption band in the infrared at 7.8 \ensuremath{\mu} and the ultraviolet absorption at 3065 A are proportional to the nitrogen concentration of the crystal. A corresp…
The characteristic electron energy loss spectrum of aluminum has been measured by analyzing the energy distribution of 760-, 1000-, 1520-, and 2020-ev electrons scattered by an evaporated specimen through 90\ifmmode^\circ\else\textdegree\fi{}. Twelve loss peaks were observed, made up of combinations of elementary 10.3…
The self-consistent field method in which a many-electron system is described by a time-dependent interaction of a single electron with a self-consistent electromagnetic field is shown to be equivalent for many purposes to the treatment given by Sawada and Brout. Starting with the correct many-electron Hamiltonian, it…
Abstract A study has been made of surface recombination of hydrogen atoms on various transition metals. Hydrogen atoms were produced in the electric discharge tube by use of an alternating current. In order to prevent the reacting gas from reaching the undesired part of the sample, a method which may be called “an eff…
A new method of perturbation theory is developed in the simple LCAO MO treatment of conjugated molecules. Several useful equations are derived, giving orbital energy, electron density, and bond order of the perturbed system.
The kinetic equations describing a general chain mechanism of depolymerization are solved at steady state for a polymer having an initial ``most probable'' molecular weight distribution. Chain scission initiation, end group initiation, depropagation, intermolecular chain transfer, and several types of termination are…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFactors Affecting the Non-Newtonian Viscosity of Rigid Particles1Jen Tsi YangCite this: J. Am. Chem. Soc. 1959, 81, 15, 3902–3907Publication Date (Print):August 1, 1959Publication History Published online1 May 2002Published inissue 1 August 1959https://pubs.acs.org/doi/10.10…