Materials Literature
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The elastic, piezoelectric, and dielectric constants of a new ferroelectric crystal 5PbO · 3GeO2 have been measured. The measurements involve mostly the use of thickness modes in small plates of various crystallographic orientations. The electromechanical coupling factors turn out to be small, which makes this materia…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemistry of low-spin iron porphyrins. II. Bis(piperidine)-.alpha.,.beta.,.gamma.,.delta.-tetraphenylporphinatoiron(II)L. J. Radonovich, Allen Bloom, and J. L. HoardCite this: J. Am. Chem. Soc. 1972, 94, 6, 2073–2078Publication Date (Print):March 1, 1972Publication His…
The energy loss spectra of 25 keV electrons traversing thin films of the nucleic acid bases adenine (C5N5H5), thymine (C5N2O2H6), and uracil (C4N2O2H4) have been obtained at room temperature in the region of K-shell excitation (>285 eV), and fine structure near the carbon K edge of these materials has been anal…
The energy loss functions — Im(1/ε) of thin films of the nucleic acid bases, adenine (C5N5H5), thymine (C5N2O2H6), and uracil (C4N2O2H4) have been determined in the range 2–50 eV from energy loss experiments with 25 keV electrons at room temperature. An analysis of the electronic structure of these materials in the re…
Abstract The geometry of lattice defects can be studied in detail using the weak-beam method 1 of high resolution electron microscopy. In this paper the theoretical basis of the method is discussed, and the experimental conditions which are necessary if particular methods of image interpretation are to be used are con…
The resonances in the photoabsorption spectra of the lanthanides near the $4d$ absorption edge are interpreted as transitions of the type $4{f}^{10}4{f}^{N}\ensuremath{\rightarrow}4{d}^{9}4{f}^{N+1}$. Calculations of the $4{d}^{9}4{f}^{N+1}$ energy levels and relative $\mathrm{gf}$ values for these transitions are sho…
Abstract The early studies of chain scission in the oxidation of rubber by Dr. E. M. Bevilacqua, and his subsequent work on the identification of the various acids, methyl ketones, and other volatile products of the oxidation reaction, have contributed much to our present knowledge of the nature of the processes invol…
The magnetic properties of the rare-earth metals and a number of the alloy and compound systems formed with rare earths are discussed. Emphasis is placed on current experimental results of bulk magnetic measurements and related transport phenomena and their bearing on theoretical studies. Topics covered include exchan…
Single crystals of Cr 3 Te 4 with the pseudo-NiAs type structure have been made by chemical transport method in order to investigate the anomaly below 80 K. The saturation moment at 4.2 K is equal to 1.79±0.03 µ B per Cr 1- x Te (x=0.25), and the Curie temperature is 316 K. The magnetization only in the direction to t…
Application of an electric field to a thin layer of nematic liquid-crystal causes the formation of a lattice of cylindrical lenses within the liquid-crystal material. An expression for the far-field diffraction pattern of light transmitted through this lattice is derived. The observed diffraction pattern agrees with t…
Spatially uniform birefringences tunable over the range 0. 0–0. 15 for applied voltages less than 20 V rms and with a sharp threshold below 4 V rms are obtained for thin layers of nematic liquid crystals with negative dielectric anisotropy. The achievement of spatially uniform tunable birefringence with negative-diele…
It is shown from measurements of the resistivity ratio (RR ≡ resistivity at room temperature divided by resistivity at 10°K), superconducting transition temperature, and transition-temperature width that high-quality single-crystal niobium films can be fabricated by rf sputtering. The observed dependence of RR on samp…
The effect on the interfacial gravity wave between two fluids is studied when there is a temperature gradient in the fluids. It is found that the thermal effect is closely related to the phase transformation across the interface. The interfacial conditions with mass flow are first derived. Then the dispersion relation…
Summary The adsorption of silicate and phosphate from pure and mixed solutions by four soils known to fix phosphate strongly has been measured. The adsorption at constant pH for each acid from its pure solution follows the Langmuir isotherm. The maximum adsorption of silicate by three of the soils from the pure soluti…
The scattering of x rays from noncrystalline samples of BeF2 and SiO2 at 25°C has been measured and analyzed. The diffraction patterns, typical of the atomic arrangement found in liquids, show interference to values of the scattering variable s=16 and beyond. The glasses contain BeF4 (SiO4) tetrahedra joined at the co…
Dielectric specimens in the shape of a frustum of a cone were evaluated for surface flashover strength in vacuum of 10-5 torr. Data were obtained for positive and negative pulses of several hundred kilovolts amplitude and with rise times in the nanosecond and microsecond region. The results indicate that most material…
I - Absorption of Finite-Amplitude Waves.- II - Acoustic Radiation Pressure.- III - Acoustic Streaming.- IV - Pulsations of Cavitation Voids.- V - Experimental Investigations of Ultrasonic Cavitation.- VI - The Cavitation Zone.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitrogen-hydrogen tautomerism in porphyrines and chlorinesC. B. Storm and Y. TekluCite this: J. Am. Chem. Soc. 1972, 94, 5, 1745–1747Publication Date (Print):March 1, 1972Publication History Published online1 May 2002Published inissue 1 March 1972https://pubs.acs.org/doi/10.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNovel antiferromagnetic oxo-bridged manganese complexP. M. Plaksin, R. C. Stoufer, M. Mathew, and G. J. PalenikCite this: J. Am. Chem. Soc. 1972, 94, 6, 2121–2122Publication Date (Print):March 1, 1972Publication History Published online1 May 2002Published inissue 1 March 197…
Abstract Calcite phases with different amounts of ferrous iron (determined by microprobe analysis) are distinguishable by study of stained thin sections and stained acetate peels. We have defined four such phases, they are (a) non-ferroan calcite (0.0% FeO; red stain), (h) ferroan calcite I (0.5% to 1.5% FeO; red-purp…