Materials Literature
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Tests are described on new master echelles of very large size and on others having unusually high blaze angles, produced on interferometrically controlled ruling engines. Defects arising from the gravitational distortion of large grating blanks during ruling were reduced by the use of calibrated edge-supporting spring…
The lattice sums required to evaluate Madelung constants of ionic crystals are very slowly convergent if summed directly. A method is given of transforming these sums to other series which not only are rapidly convergent but involve the use of elementary functions only.
The development and testing of an ir hemi-ellipsoidal mirror reflectometer (HEMR), operational over a wavelength interval of 2-34 microm, are described. This optical system measures the hemispherical-directional reflectance of room temperature samples relative to a specular gold-coated surface. For a source and sample…
Abstract Tensile deformation of poly(methyl methacrylate) carried out under hydrostatic pressures up to 4 kbar has shown that the pressure‐transmitting fluid (silicone oil) strongly affects the mechanical properties of this polymer. Unsealed specimens fractured in a brittle manner at almost the same strain of 5% in th…
Abstract A series of 15 N labeled 2‐acylpyrroles was prepared and the nitrogen and proton n.m.r. spectra obtained. 15 N chemical shifts for these compounds are reported for the first time. No correlation between the nitrogen chemical shift and any Hammett substituent constant could be found. No variation in J ( 15 NH…
Pyridoxal 5'-phosphate labeled to the extent of 90% with 13C in the 4' (aldehyde) and 5' (methylene) positions has been synthesized. 13C NMR spectra of this material and of natural abundance pyridoxal 5'-phosphate are reported, as well as 13C NMR spectra of the Schiff base formed by reaction of pyridoxal 5'-phosphate…
The temperature dependence of the EPR frequency is calculated for antiferromagnets with inequivalent g -tensors. Contrary to the previous results for the systems with isotropic g -factor, the EPR frequency increases rapidly for every orientations of the magnetic field as the temperature is reduced. The observed temper…
Abstract For very small crystallites diffraction theory shows not only broadening of powder lines, but generally also a shift of the line position, depending on the change of the structure factor over the range of broadening. For decreasing thickness of kaolinite crystals (less than 50 layers) an increasing shift of r…
Abstract Tensile properties of injection and compression molded ABS, terpolymer of acrylonitrile, butadiene, and styrene, were measured as a function of aging time at 40 to 90°C. Both air and nitrogen atmospheres were employed to separate the oxidative and thermal effects. Results demonstrate that tensile elongation i…
The equilibrium phases in the lithium sulfide‐ferrous sulfide system were determined by differential thermal analysis and x‐ray diffraction analysis. A compound Li 2 S · FeS , which melts incongruently at 885 ° ± 5 ° C to Li 2 S , and a liquid containing approximately 50.5 mole per cent ( m / o ) FeS , and has a trans…
Abstract This paper concerns the action of plasticizers and nucleating agents on the crystallization of bisphenol‐A polycarbonate. The influence of plasticizers is to increase the rate of crystallization to a great extent using 10 percent of a plasticizer such as trimellitic acid, tridecyloctyl ester. The influence of…
The three lowest energy levels of ${\mathrm{Ho}}^{3+}$ in ${\mathrm{LiYF}}_{4}$ are determined by submillimeter EPR spectroscopy. The ground state is a ${\ensuremath{\Gamma}}_{3,4}$ doublet. The next excited levels are two ${\ensuremath{\Gamma}}_{2}$ singlets at 6.8 and 23.8 ${\mathrm{cm}}^{\ensuremath{-}1}$. The ${g}…
The reflection spectra of BiI s single crystals were measured between 1.5 and 5.5 eV at 6, 77 and 286 K. A Kramers-Kronig dispersion analysis of the data was made, and the intrinsic absorption coefficient and the real and imaginary parts of the dielectric constants were calculated. The large peak at 2.0 eV is ascribed…
Unpolarized specular reflectance spectra at near-normal incidence were measured in the silicates olivine, pyroxene, spinel and Al-garnet in the photon energy range 4–14 eV at 300°K, and the optical and dielectric functions were obtained from the reflectance by Kramers-Kronig analysis. The spectra indicate that these m…
For compounds of the type YCo5xNi5−5x the saturation moment and Curie temperature were determined. For large Co concentrations the rigid-band approach applies. The magnetic splitting of the 3d band collapses near x=0.2. Magnetic isotherms were studied at 4.2 K as a function of concentration. The form of the virgin mag…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilane reductions in acidic media. VII. Aluminum chloride catalyzed hydrogen-halogen exchange between organosilanes and alkyl halides. An efficient hydrocarbon synthesisMichael P. Doyle, Charles C. McOsker, and Charles T. WestCite this: J. Org. Chem. 1976, 41, 8, 1393–1396Pu…
Abstract The infrared and Raman spectra of polycrystalline PbHPO 4 , PbHAsO 4 , CaHPO 4 , and BaHPO 4 were measured at room temperature in the range between 4000 and 30 cm −1 , and the temperature dependence of the dielectric constant of these materials was studied. The OHO hydrogen bonds in PbHPO 4 and PbHAsO 4 are…
A theoretical and experimental study has been carried out on extrudate swell B, especially the influence of rheological properties and applied take-up force on the emerging melt. The problem is analyzed in terms of (1) dimensional analysis, (2) force–momentum balances, (3) partially constrained elastic recovery. Analy…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCharge-transfer polymers containing 7,7,8,8-tetracyanoquinodimethan and tetrathiafulvaleneW. R. HertlerCite this: J. Org. Chem. 1976, 41, 8, 1412–1416Publication Date (Print):April 1, 1976Publication History Published online1 May 2002Published inissue 1 April 1976https://pub…
A mathematical model to describe the contamination of steel surfaces by 60Co in high-temperature water is developed. The model assumes that 60Co is incorporated into the growing oxide film on the steel, so that the contamination rate is governed by corrosion kinetics. Release to inactive coolant is controlled by solid…