224,758 research outputs found

    Stripe-line coil for magnetic-field generation in bubble memory devices

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    Coil etched from conductive film has better field uniformity than wire-wound coils and less coil loss at high-frequency operation

    Open coil structure for bubble-memory-device packaging

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    Concept has several important advantages over close-wound system: memory and coil chips are separate and interchangeable; interconnections in coil level are eliminated by packing memory chip and electronics in single structure; and coil size can be adjusted to optimum value in terms of power dissipation and field uniformity

    Non-analyticity of the groud state energy of the Hamiltonian for Hydrogen atom in non-relativistic QED

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    We derive the ground state energy up to the fourth order in the fine structure constant α\alpha for the translation invariant Pauli-Fierz Hamiltonian for a spinless electron coupled to the quantized radiation field. As a consequence, we obtain the non-analyticity of the ground state energy of the Pauli-Fierz operator for a single particle in the Coulomb field of a nucleus

    Electron and phonon correlations in systems of one-dimensional electrons coupled to phonons

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    Electron and phonon correlations in systems of one-dimensional electrons coupled to phonons are studied at low temperatures by emphasizing on the effect of electron-phonon backward scattering. It is found that the 2kF2k_F-wave components of the electron density and phonon displacement field share the same correlations. Both correlations are quasi-long-ranged for a single conducting chain coupled to one-dimensional or three-dimensional phonons, and they are long-ranged for repulsive electron-electron interactions for a three-dimensional array of parallel one-dimensional conducting chains coupled to three-dimensional phonons

    Juncture stress fields in multicellular shell structures. Volume IV - Stresses and deformations of fixed-edge segmental spherical shells Final report

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    Equations for thin elastic spherical shells and digital program for analysis of stresses and deformation of fixed edge segmental spherical shells - solution by finite difference techniqu

    Advances in large-diameter liquid encapsulated Czochralski GaAs

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    The purity, crystalline perfection, and electrical properties of n- and p-type GaAs crystals grown by the liquid encapsulated Czochralski (LEC) technique are evaluated. The determination of the dislocation density, incidence of twinning, microstructure, background purity, mobility, and minority carrier diffusion length is included. The properties of the LEC GaAs crystals are generally comparable to, if not superior to those of small-diameter GaAs material grown by conventional bulk growth techniques. As a result, LEC GaAs is suitable for application to minority carrier devices requiring high-quality and large-area substrates

    High purity low dislocation GaAs single crystals

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    Recent advances in GaAs bulk crystal growth using the LEC (liquid encapsulated Czochralski) technique are described. The dependence of the background impurity concentration and the dislocation density distribution on the materials synthesis and growth conditions were investigated. Background impurity concentrations as low as 4 x 10 to the 15th power were observed in undoped LEC GaAs. The dislocation density in selected regions of individual ingots was very low, below the 3000 cm .3000/sq cm threshold. The average dislocation density over a large annular ring on the wafers fell below the 10000/sq cm level for 3 inch diameter ingots. The diameter control during the program advanced to a diameter variation along a 3 inch ingot less than 2 mm
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