Materials Literature
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Electrical conductivities of binary alkali and thallous silicate glasses have been measured as a function of composition, temperature, and frequency. The best approximation to the activation energy for dc conduction can probably be obtained by extrapolating its frequency dependence to zero frequency, although values o…
Abstract The thermodynamic properties of crystalline and amorphous poly(2,6‐dimethyl‐1,4‐phenylene ether) (PPO Registered trademark of General Electric Company. polymer, General Electric Co.) have been studied calorimetrically between 80 and 570°K. The calculated configurational entropy of this polymer, of similar mag…
Abstract The submicroscopic morphology of uniaxially deformed isotactic polypropylene films has been examined by small‐angle light scattering (SALS), electron microscopy, optical microscopy, small‐angle x‐ray scattering (SAXS), wide‐angle x‐ray diffraction, birefringence, sonic modulus, and density methods. Several ne…
The dyebanding and tattooed patch techniques of estimating wool production were compared in three experiments, and in two of these, mean diameters of wool fibres taken from the tattooed patches and from the dyebands were also determined. There were significant differences at some times of the year between the two esti…
It is shown that a free-volume treatment of the relaxational behavior of a polymer can be extended into the glassy region. A modified form of the WLF equation is derived in which the temperature is replaced by Te, a parameter related to the “frozen” free volume in the glass and defined such that Te = T at equilibrium.…
Abstract The ceric ion‐cellulose redox system has been studied for grafting acrylonitrile on cotton fibers. Grafting yields are very high as compared to the persulfate‐thiosulfate redox system reported earlier. Traces of copper sulfate in the reaction mixture do not increase grafting yields, unlike the persulfate‐thio…
Abstract The energy component of the stress has been determined for poly(vinyl alcohol) networks in swelling equilibrium with a series of water–ethylene glycol compositions. The data are analyzed by using the equations describing the thermoelasticity of networks in swelling equilibrium. The ratio f e / f of the energy…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSubstituent effects on the photoaddition of diphenylacetylene to 1,4-naphthoquinonesS. P. Pappas and Norman A. PortnoyCite this: J. Org. Chem. 1968, 33, 6, 2200–2203Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1 June 19…
1. Experiments were conducted on isolated and in situ hearts of 4 species of tunicates in order to investigate beat reversal. The mechanical and electrical properties of in situ and isolated hearts were found to be the same. The intracardiac pressure was found to affect the excitability of pacemakers and it could be a…
The crystal structure of trans-1,4-polybutadiene has been reported by Natta et al. to be pseudo-hexagonal below its solid-phase transition temperature. In the present X-ray structure analysis, it is revealed that the crystal belongs to the monoclinic system with the space group P21/a. The unit cell, with the lattice c…
It is shown theoretically that, for non-Kramers paramagnetic ions, the second-order Raman phonon process gives a spin–lattice relaxation rate varying as T 5 at low temperatures. This new relaxation rate for non-Kramers ions is similar to the one discussed by Orbach and Blume for multilevel Kramers ions. An unusual fea…
Incoloy(1) nickel-iron-chromium Alloy 825 can become sensitive to intergranular attack by exposure to temperatures in the 1200-1400 F (649-760 C) range. Sensitivity to intergranular attack (as measured by the Huey test) can be correlated to the presence of a chromium-depleted area adjacent to the grain boundary. This…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe disordered and β-conformations of silk fibroin in solutionEisaku. Iizuka and Jen Tsi. YangCite this: Biochemistry 1968, 7, 6, 2218–2228Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1 June 1968https://pubs.acs.org/doi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of carbon macrocycles to C120E. Wasserman, D. A. Ben-Efraim, and R. WolovskyCite this: J. Am. Chem. Soc. 1968, 90, 12, 3286–3287Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1 June 1968https://pubs.acs.org/doi/…
The number of ionizations on a given j shell in any electron-bombarded target has been calculated analytically by means of the Bethe formulae. A general formula for the atomic number correction has been derived in the form of an equation using parameters that are functions of target composition and accelerating voltag…
Low-temperature conductivity measurements on glasses containing transition-metal oxides TiO2 and V2O5 reveal a sharp break in the slope of the dependence of log conductivity upon reciprocal temperature. At low temperatures, the slope corresponds to a low-activation-energy process (0–0.2 eV) while at high temperatures…
New permanent magnet materials containing rare-earth elements (RE) have been discovered. For the most part, these alloys are based on the hexagonal intermetallic compounds, Co5RE. Replacement of cobalt with copper in some of these rare-earth compounds results in solid materials with substantial permanent magnet proper…
Five glasses and four polycrystalline compounds of the lithium borate system have been subjected to γ irradiation at 77°K and subsequently examined by ESR techniques at 9.1 and 35 GHz while maintaining this low temperature. The familiar “five-line-plus-a-shoulder” spectrum is observed at X band for both the Li2O·4B2O3…
The replacement of magnetite by hematite is not by octant sectors but is independent of sample coordinates and is penetrative to at least the scale of developed \[111\] parting. Anisotropy increases with depth into the octahedron. Hematite c-axis orientation perfection occurs 5 mm deep into the crystal. The replacemen…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnionic ring-opening polymerization of thiolactonesCharles G. Overberger and Jurgen K. WeiseCite this: J. Am. Chem. Soc. 1968, 90, 13, 3533–3537Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1 June 1968https://pubs.acs.or…