Materials Literature
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When pumped by radiation from a Si–GaAs diode, the luminous efficiency of Y3OCl7:Yb3+, Er3+ is comparable to that of visible emitting GaP diodes. By varying the Yb3+ concentration, phosphors have been made which produce a red or yellow visual response.
The dielectric theory of electronegativity differences is used to calculate second- and third-order nonlinear susceptibilities of covalent crystals. With no adjustable parameters excellent agreement is obtained for ${\ensuremath{\chi}}^{(2)}$ when allowance is made for Coulombic correlations. The experimental values $…
In a nematic system, the molecular axes tend to be aligned parallel to each other, but there are some fluctuations in the alignment. They give rise to a strong scattering of light. By a frequency analysis of the outgoing light, one can measure the power spectrum of these fluctuations, i.e., their dynamical behavior. T…
Efficient infrared-to-visible conversion by Yb3+–Er3+ and Yb3+–Ho3+ ions in BaLuF5 and BaYF5 is reported. When pumped by radiation from a Si–GaAs diode, the power conversion efficiency for green emission from BaYF5:Yb3+, Er3+ is equal to that for green emitting GaP diodes.
Behavior of individual dislocations is investigated by stretching the foil single crystals of Fe-3% Si inside a 500 kV electron microscope. Formation of dislocation dipole trails and loops are continuously observed under the microscope, and is attributed to jogs caused by cross glide. Slip traces of individual disloca…
The Raman spectra of LaAl${\mathrm{O}}_{3}$, PrAl${\mathrm{O}}_{3}$, and NdAl${\mathrm{O}}_{3}$ have been observed at temperatures from 10 to 1135\ifmmode^\circ\else\textdegree\fi{}K. Each of these materials evidences a nominally second-order trigonal cubic phase transition; that in LaAl${\mathrm{O}}_{3}$ has previous…
The appearance of phase-contrast, Fresnel fringes and various forms of diffraction contrast in images produced by transmission scanning electron microscopes can be understood simply by invoking the principle of reciprocity to equate the imaging conditions to those relevant to a conventional electron microscope.
Expressions are derived for the voltage and current in insulators under charge limited conditions using running wave expression for the charge carriers, taking into account displacement and field induced currents. Using these the frequency characteristics of the voltage, current and impedance is derived. It is seen th…
Article Kinetic Study of the Thermal Decomposition of Cobaltous Carbonate at Atmospheric Pressure was published on July 1, 1969 in the journal Zeitschrift für Physikalische Chemie (volume 241O, issue 1).
The focal properties and spherical aberration of a simple model of a field omission electron gun are investigated theoretically. Results are presented graphically. For a fixed source position, spherical aberration decreases as the grid aperture increases, but for a fixed image position, spherical aberration decreases…
Magnetomechanical damping measurements are commonly made using wire specimens in a torsion pendulum. Twisting the cylindrical wires produces tensile stresses along a helix. An analytical study was made relating the direction of these stresses with the directions of the crystallographic axes assuming three different or…
Measurements of the thermionic emission and electrical conductivity as a function of the temperature for fixed states of activation were obtained for each of the four barium chalcogenides. From the temperature dependences of these quantities the electron affinities were determined. The values obtained were 0.57 for Ba…
Abstract Polymer‐polymer interaction was used for the preparation of graft polymers of polyethylene oxide on starch. Preformed polyethylene oxide having hydroxyl end groups was converted to the chloroformate derivative and reacted with starch alkoxide. Watersoluble graft polymers were obtained free of cross linking. T…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNovel oxidative fragmentation. The formation of benzyl azide from the reaction of 1,1,4,4-tetrabenzyltetrazene with lead tetraacetateGen Koga and Jean P. AnselmeCite this: J. Am. Chem. Soc. 1969, 91, 15, 4323–4324Publication Date (Print):July 1, 1969Publication History Publi…
The excellent high-temperature mechanical properties and other desirable characteristics of polybenzimidazole (PBI) polymer systems make these systems attractive candidates for development as ablative heat-shield materials. This paper describes the formulation of several new low-density polybenzimidazole composites. T…
Abstract The effect of the room‐temperature first‐order transition on the plastic yield behavior of polytetrafluoroethylene (PTFE) has been investigated. Stress‐strain curves were measured at different strain rates and temperatures. Tensile creep under constant dead load was also measured as a function of temperature…
The set of optical constants of germanium reported by Marton and Toots, from 8 to 25 eV, have been assessed and found to be internally consistent to within ±5%. An extension of the n and k values up to photon energy of 100 eV using Hunter's k values also has been studied. The analysis consisted of an internal consiste…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactions of bivalent sulfur compounds-copper(II) complexesTeruaki Mukaiyama, Koichi Narasaka, and Hisao HokonokiCite this: J. Am. Chem. Soc. 1969, 91, 15, 4315–4317Publication Date (Print):July 1, 1969Publication History Published online1 May 2002Published inissue 1 July 19…
Abstract Physical characteristics of rubber network structures usually enumerated and discussed are network chain density, crosslink functionality, average chain length between crosslinks, entanglements which act somewhat like crosslinks, and free chain ends which are network defects. Chemical factors include structur…
Ac and dc conductivity, tunneling, and optical transmission and reflectance studies have been made on amorphous and crystalline (rhombohedral and NaCl) GeTe films (80 Å to 10 μ thick) prepared by evaporation and by sputtering. The crystalline films behave like a p-type degenerate semiconductor with Fermi level ∼0.3–0.…