Materials Literature
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Abstract Ammoxidation of acrolein (Al) on Fe 2 O 3 ‐Bi 2 O 3 ‐P 2 O 5 (44.5:44.5:11.0 mol%) catalyst was studied in a fixed bed reactor. The main products were acrylonitrile (AN), CO 2 and acetonitrile; and CO was negligibly small. The rate equations for Al conversion and product formation, together with their apparen…
Abstract The values of the vitreous transition temperature, T g , of three poly(methacrylic ester)s having bulky side groups are correlated with structural effects. T g has been obtained experimentally by means of differential calorimetry and by the tensiometric method suggested by Ferroni . The experimental values of…
Using ENDOR we have characterized the 23Na and 1H hyperfine structure of the CO2− radical ion in sodium formate single crystals. In contrast to previous studies we have detected CO2− in uv irradiated samples. ENDOR studies of the 23Na hfs together with CNDO calculations indicate that the CO2− forms a tight ion pair wi…
A method, using differential scanning calorimetry, has been developed to estimate quantitatively orthorhombic and monoclinic sulfur in sulfur materials. Sulfur cooled from the melt at 120°C immediately gives monoclinic sulfur which reverts to orthorhombic sulfur within 20 hr. Limonene, myrcene, alloocimene, dicyclopen…
Abstract 1. A direct correlation between bound rubber content and molecular weight of soluble polymer was found for a wide range of carbon black samples and processing conditions in SBR. 2. No significant polymer degradation occurred during the ineorporation of carbon black into SBR rubber. 3. A theory was proposed to…
Abstract Numerous workers have examined the weathering products of soil minerals and have proposed empirical weathering sequences. The present paper outlines the development of a thermodynamic model that predicts in a systematic way several mineral transformations that can occur in soils. According to this model, the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUse of structural probe ions for relaxation studies in glasses. I. Spectroscopic properties of cobalt(II) in chloride-doped potassium nitrate-calcium nitrate glassesA. Barkatt and C. A. AngellCite this: J. Phys. Chem. 1975, 79, 20, 2192–2197Publication Date (Print):September…
Abstract The characterization of recently synthesized (Pro‐Pro‐Gly) n , n = 7, 8 is described, along with melting profile studies of its association equilibrium, and thermal quenching studies of the kinetics of its association reaction. The order of the kinetic reaction is about 3, implying that three peptide chains a…
Abstract A polymer bearing hydroxamic acid groups and having a high affinity for iron(III) was prepared through the following procedure. Acryloylalanine (III), prepared by the reaction of acryloyl chloride with alanine, was treated with N ‐hydroxysuccinimide in the presence of dicyclohexylcarbodiimide to give the N‐hy…
Magnetostriction measurements have been carried out in the cubic Laves phase compounds DyCo 2 , HoCo 2 and ErCo 2 from 10K to well above their respective Neel temperatures T N . The observed magnetostrictions are very large ( approximately 10 -3 ). The measurements confirm the extremely high anisotropy of these materi…
The fluorescence and phosphorescence of photomultiplier window materials under electron irradiation have been investigated using a Sr(90)-Y(90) beta emitter as the electron source. Spectral emission curves of uv-grade, optical-grade, and electron-irradiated samples of MgF(2) and LiF, and of CaF(2), BaF(2), sapphire, f…
Phases with the stoichiometry R5Co19have been observed in the rare earth-cobalt systems with R = La, Ce, Pr, and Nd. These phases may play a significant role in the development of coercive force in RCo5-based permanent magnets containing the light rare earths, particularly mischmetal. The present paper reports Curie t…
The X-ray intensity distribution in the incident plane for a crystal containing a straight dislocation has been computed. The trajectories of the wave fields have been drawn in the case of a planar or spherical incident wave, and it has been shown that the interaction of the defect with the X-rays gives rise to new di…
Comparisons of calculated solutions with experimental results for the impact of a 9.53-mm-diam nylon sphere on a 12.7-mm-thick steel plate at 5.182 km/sec are presented. Numerical solutions are difficult to obtain with existing Eulerian codes because of the need for accurate treatment of material strength and the defi…
The cation distribution of single crystal manganese ferrites Mn1-yFey[MnyFe2-y]O4with0.06 \leq y \leq 0.24was modified by appropriate heat treatment at temperatures 300-600°C. With these samples the Curie temperature, the magnetocrystalline anisotropy, the spontaneous magnetization and the differential susceptibility…
The influence of the deviation from stoichiometry on the magnetic properties has been investigated on the compositions given by the formula (NiO)α(ZnO)1-α(Fe2O3)xwhere α = 0.30 ; 0.36 and 0.9s, Tc), the influence of the deviation is much lower but unambiguous. It is the variation of the Curie temperature with x which…
In the context of an SCF π-electron theory an exact expression is derived which yields xπ ⊥, the total π-electron contribution to the magnetic susceptibility perpendicular to the plane of a polycyclic conjugated hydrocarbon. Once given the first-order correction to the bond-order matrix of the molecule in question (wh…
Room‐temperature optical absorption spectra, electron spin resonance spectra at 15° to 18°K, electrical conductivity, and emf measurements on concentration cells at 1620°C are analyzed and used to determine the defect structure of Codoped α‐Al 2 O 3 . The crystals are mixed ionic and electronic conductors at 1620°C: i…
When the network system is limited, most ferroelectric glass‐ceramics will produce a fully crystallized transparent body when cerammed at low temperatures. Higher‐temperature heat treatment results in crystal growth and gradual loss of transparency. In the transparent state, the crystal size is limited to ∼2000 Å. Pie…
Microscopic details of physical changes occurring in steel plates impacted at hypervelocities by spherical projectiles of several materials are studied by means of metallographic examinations of polished and etched target cross sections. A hemispherical volume of material beneath the impact site undergoes the pressure…