Materials Literature
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At 4 and 77 K, photoluminescence from nominally undoped and 0.0025% Cr-doped CaTi${\mathrm{O}}_{3}$ shows identical spectra in the infrared with an intensity ratio of 1:2. The emission is attributed to the $^{2}E\ensuremath{\rightarrow}^{4}A_{2}$ transition of the ${\mathrm{Cr}}^{3+}$ ion at a ${\mathrm{Ti}}^{4+}$ sit…
1. Retinol and stilbene are both isomerized when they are illuminated anaerobically in the presence of flavins. 2. Triplet quenchers (e.g. oxygen, potassium iodide and paramagnetic ions) inhibit the reaction more efficiently than they quench flavin fluorescence. At 77 degrees C in a diethyl ether-isopentane-ethanol (5…
Thermal expansion characteristics of a group of polycrystalline graphites have been measured to 2400°C by a method which permits acquisition of meaningful expansion data without resorting to reference standards. Direct measurements on specimens while in the furnace were accomplished by using two 8-in. focal length Gae…
An hour after the damage of the shell in Euplecta indica (Pfieffer) a thin, structureless, basophilic regeneration membrane appears. Thereafter, a large number of amoebocytes precipitate on this membrane. Soon these break up and contribute their cytoplasmic contents to the regenerate. This is positive for glycoprotein…
The influence of aluminum-containing Lewis acids, e.g., AlCl3, AlEtCl2, AlEt2Cl, AlEt3, and AliBu3, on polyisobutylene, isobutylene-isoprene copolymer (butyl rubber), and chlorinated butyl rubber has been investigated in nonpolar and polar solvents at various Lewis acid concentrations in the temperature range -10 to -…
Comparisons of theoretical electron-bremsstrahlung cross sections for Al and Au from the work of Brysk, Zerby, and Penny are made with new experimental values at incident-electron energies of 0.05 and 0.20 MeV. Photon energies of 10, 20, 30, and 40 keV are considered in the angular region from 10 to 120 deg at 0.050-M…
Two-dimensional numerical analyses have been performed of projectile impacts at 15,00020,000 fps into finite laminated targets consisting of plastic layers backed by aluminum substrates. These analyses used the SHAPE code, with a hydrodynamic-elastic-plastic distortional model. Three solutions are discussed. The first…
Tumble-drying from the wet fabric state is shown to be a reasonable means of fully-relaxing rib structures. By this technique, an approximate discrimination can be made between dimensional changes due to relaxation and felting of all- wool rib structures. Upon washing from the fully-relaxed state, untreated fabrics fe…
Abstract Determination by X-ray diffraction of the relative proportions of component minerals in sediments and rocks involves comparison of the integrated intensity of selected reflections from component minerals in the unknown mixture to standard calibration curves. Although the analysis may be rapid and precise, a n…
The lattice parameter of the α copper-titanium solid solution was measured as a function of titanium concentration. The value of aO increased non-linearly from 3.6150 Å for pure copper to 3.6421 Å for an alloy containing 7.6 at.% titanium. The rate of change of the parameter increased up to 3 at.% titanium and decreas…
Abstract The effects of simultaneous additions of electrolyte and peptiser to dispersions of the synthetic hectorite-like clay, Laponite, have been studied. It has been unexpectedly discovered that whereas many cations cause gelling and flocculation of the dispersions as expected by colloid chemical theory, some catio…
Article Refinement of the crystal structure of cubanite and polymorphism of CuFe2S3 was published on December 1, 1970 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 132, issue 1-6).
Cation ordering in magnesium and nickel ferrites was studied by X-ray diffraction measurements carried out at the temperature of equilibration and also on quenched specimens. The order parameters on quenched specimens agreed with results previously reported by others but not with values measured at temperature. Previo…
One of the methods in use for measuring the kinetics of isothermal crystallization of polymers is the recording of the depolarization of plane-polarized light by a microscope specimen. A relation between this depolarization and the volume fraction crystallized has been derived taking into account the polycrystalline n…
In this study, previously derived relationships between critical anodic current density and chemical composition of Type 304 stainless steel were used to develop a new series of 18Cr-8Ni alloys with improved passivating properties. Electrochemical and corrosion tests confirm that these special Type 304 alloys have sup…
Abstract The diametrical crushing strength of an ideal system of compacted particulate material, and the relation between strength and mean compaction pressure depend on the time at which the strength is determined. Strength increases of over 100% during the first hour after compression are attributed to stress relief…
In the spectral range 0.5<hv<11.9 eV, reflectance data were obtained from molybdenum and ruthenium films, vapor deposited in ultra-high vacuum and extended to 14 eV using the reflectance of a polished bulk sample. The Mo data are different from previously reported data. The optical constants are obtained by a Kr…
The dc resistivity of nickel‐zinc ferrite was studied as a function of nickel/zinc ratio, apparent density, temperature, and grain size. Resistivities of Ni 0.40 Zn 0.51 Fe 1.90 O 4 – and Ni 0.35 Zn 0.65 ‐Fe 1.90 O 4 – are similar. Evaluation of samples sintered between 1100° and 1220°C showed that densification proce…
The absorption and magnetic circular dichroism (M.C.D.) spectrum of the IrBr6 2- ion at room and liquid helium temperature has been studied in the host crystals (NH4)2SnBr6, K2SnBr6 and (C2H5NH3)2SnBr6 in the region ∼11 000–21 000 cm-1. An interpretation of the spectrum is presented which differs significantly from th…
A unique method was developed for mechanical testing of brittle materials to create an unlimited number of stress ratios in the tension‐tension and tension‐compression quadrants. The stress states are achieved by internal and external pressurization of tubular specimens in a special pressure vessel. Failure envelopes…