Materials Literature
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Sharp no-phonon lines associated with phonon sidebands have been observed in 4 f -5 d excitation spectra for Tb 3+ and Ce 3+ as well as in emission spectra of Ce 3+ , in Sc, Y and Lu orthophosphates at low temperatures. The spectra manifest themselves as if the 5 d electron did not see the tetragonal field component.…
Although some reports of the water-resisting life of polyethylene-insulated wires have been made, studies of mechanism of the deterioration phenomenon have been scarcely reported. In this paper, it is pointed out that a major cause of the deterioration of polyethylene-coated wire in water is the occurrence of the "tre…
Calculations of $\ensuremath{\alpha}$-particle stopping cross sections based on the theories of Lindhard et al. using the Hartree-Fock-Slater atomic-charge distribution provide generally good agreement with previously obtained experimental results. In particular, the calculations are helpful in understanding the struc…
A method is suggested for systematically obtaining model potentials that accurately reproduce spectroscopic or scattering data. Applications are made to atomic systems consisting of one electron outside a closed shell for the closed shells Li + , Na + , K + , He and Ne.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSo-called "ladder structure" of equilibrated phenylsilsesquioxaneC. L. Frye and J. M. KlosowskiCite this: J. Am. Chem. Soc. 1971, 93, 18, 4599–4601Publication Date (Print):September 1, 1971Publication History Published online1 May 2002Published inissue 1 September 1971https:…
In the case of a periodic object, the wave amplitude in every point of a Fresnel diffraction pattern may be obtained from the values of the wave amplitude at a finite number of points in the object plane. This results is applied to the case of pure phase objects. A simple condition on the object structure is derived,…
A new method is presented of solving Laplace's equation for equidiameter coaxial cylinders separated by a finite distance. The results are used to obtain the focal lengths, focal points and spherical aberration coefficients of double cylinder electrostatic lenses over a large range of voltage ratios and cylinder separ…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelective catalytic reaction of hydrogen with nitric oxide in the presence of oxygenMordecai Shelef, James H. Jones, Joseph T. Kummer, Klaus Otto, and E. Eugene WeaverCite this: Environ. Sci. Technol. 1971, 5, 9, 790–798Publication Date (Print):September 1, 1971Publication H…
Thirty‐four scleractinian coral samples, including both hermatypic and ahermatypic varieties, have been analyzed for trace elements. Acid leaching has been used to infer the distribution of elements between the coral skeleton (acid‐soluble fraction) and detrital phases (acid‐insoluble). Sr, U, Ba, Cu, B, Li, and Zn ar…
A general technique for the measurement of the solid-liquid interfacial free energy, γSL is proposed, based on a theoretical analysis of the equilibrium shape of a grain boundary groove in an applied temperature gradient. The analysis extends the work of Bolling and Tiller to account for unequal thermal conductivities…
Coastal surface seawater off southern California was enriched with phosphate, silicate, vitamins B 12 , B 1 , and biotin, a chelated trace metal mixture, and with nitrogen as nitrate, ammonium, or urea, and the cultures were incubated on deck in daylight. Natural phytoplankton present in the seawater served as inoculu…
Sintering of Sm-Co magnets was first reported on in 1969. Because of success in sintering, Sm-Co magnets are now enjoying added importance. Many processing parameters are critical in the preparation of high quality permanent magnets of Sm-Co. One of these is the sintering temperature. Varying the sintering temperature…
A mechanism for the 'charging' artifacts which obscure detail on SEM images of high resistivity specimens is described. An interaction equation, relating the properties of specimen and environment, predicts negative charge build-up and large potential fields. Charging effects are traced to the specular deflection of b…
Technical Briefs Fire-Fighting Benefits of Polymeric Friction Reduction Andrew G. Fabula Andrew G. Fabula Fluid Mechanics Branch, Naval Undersea Research and Development Center, Pasadena Laboratory, Pasadena, Calif. Search for other works by this author on: This Site PubMed Google Scholar Author and Article Informatio…
The dislocation aspects of the earlier model of Bishop and Chalmers for the structure of high angle symmetric tilt boundaries in metals is extended to twist and more general boundaries having both tilt and twist components. The expected strain contrast in high angle grain boundaries is discussed. It is concluded that…
The magnetic transitions of the Cr-Te system has not been explained by a suitable model. Therefore, the magnetic properties of the single crystals of Cr 2-δ Te 3 , prepared by the chemical transport method, were investigated. From the measurement of the magnetic susceptibility above room temperature S =3.0 8 /2 per Cr…
Optical absorption and emission spectra of vanadium impurities in Y3Al5O12 crystals are reported. Crystals doped with vanadium only and with vanadium counterdoped with charge-compensating calcium and silicon ions were studied. Possible valence states for vanadium include V2+, V3+, V4+; possible substitutional sites in…
Effects of grain size and grain growth in Nb‐doped BaTiO 3 on temperature and frequency dependencies of the dielectric constant were investigated. When 0.65 μm powder is sintered to an average grain size of 1 μm, two dielectric constant peaks indicate the presence of Nb‐free BaTiO 3 and of Nb‐containing material. Sing…
The extended Poole-Frenkel model presented here includes the variation of the barrier height with electric field in directions both opposite and forward to the electric force on an electron. The equation for the voltage-current characteristics based on this model gives not only the usual Poole-Frenkel equation at extr…
Electrical conduction is studied in polyethylene terephthalate and to a limited extent in polyethylene over a range of fields up to 1·2 × 10 6 V cm −1 . In common with previous investigations, it is found that the current decays with time according to an inverse power law, but this can be obviated by a conditioning pr…