9,355 research outputs found

    A Modified Hypersensitization Procedure for Eastman Kodak I-Z Spectroscopic Plates

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    Modified hypersensitization procedure for Eastman Kodak I-Z spectroscopic plate

    Mobility of Edge Dislocations in the Basal‐Slip System of Zinc

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    This paper presents the results of measurements of the velocities of 〈1210〉 (0001) edge dislocations in zinc as a function of applied shear stress. All tests were conducted at room temperature on 99.999% pure zinc monocrystals. Dislocations were revealed by means of the Berg‐Barrett x‐ray technique. Stress pulses of microsecond duration were applied to the test specimens by means of a torsion testing machine. Applied resolved shear stresses ranged from 0 to 17.2×10^6 dyn∕cm^2 and measured dislocation velocities ranged from 40–700 cm∕sec. The results of this study indicate that the velocity of edge dislocations in the basal slip system of zinc is linearly proportional to the applied resolved shear stress. These results are analyzed in terms of the phonon drag theory. Agreement between this theory and the results reported here is quite good

    Disagreement between correlations of quantum mechanics and stochastic electrodynamics in the damped parametric oscillator

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    Intracavity and external third order correlations in the damped nondegenerate parametric oscillator are calculated for quantum mechanics and stochastic electrodynamics (SED), a semiclassical theory. The two theories yield greatly different results, with the correlations of quantum mechanics being cubic in the system's nonlinear coupling constant and those of SED being linear in the same constant. In particular, differences between the two theories are present in at least a mesoscopic regime. They also exist when realistic damping is included. Such differences illustrate distinctions between quantum mechanics and a hidden variable theory for continuous variables.Comment: accepted by PR

    Mobility of Basal Dislocations in Zinc

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    This paper reports the results of an experimental study in which basal dislocation velocities were measured in zinc as a function of stress, temperature and dislocation orientation. The velocities were measured using the direct or Gilman-Johnston technique in which the individual dislocations themselves are observed. Tests were performed on 99.999% purity monocrystals. The applied resolved shear stress ranged from 0 to about 20 x 10^6 dynes/cm^2, the load durations were in the microsecond range, the test temperatures were 300, 223, 173 and 123 °K, and the measured velocities ranged from about 200 to 2000 cm/sec. Since the velocities are a linear function of stress and the velocity at a given stress increases with decreasing temperature, the velocity controlling mechanism is believed to be an interaction between the moving dislocations and the thermal waves of the lattice. The phonon viscosity and the phonon scattering mechanisms are compared to the data

    Variant N=(1,1) Supergravity and (Minkowski)_4 x S^2 Vacua

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    We construct the fermionic sector and supersymmetry transformation rules of a variant N=(1,1) supergravity theory obtained by generalized Kaluza-Klein reduction from seven dimensions. We show that this model admits both (Minkowski)_4 x S^2 and (Minkowski)_3 x S^3 vacua. We perform a consistent Kaluza-Klein reduction on S^2 and obtain D=4, N=2 supergravity coupled to a vector multiplet, which can be consistently truncated to give rise to D=4, N=1 supergravity with a chiral multiplet.Comment: Latex, 17 pages. Version appearing in Classical and Quantum Gravit

    Experimental techniques for observing dislocations by the Berg-Barrett method

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    Experimental problems in the application of the Berg-Barrett Method to the observation of dislocations in metal single crystals are discussed. The problem of background noise caused by fluorescence from the specimen and inelastic scattering is considered. A criterion for selecting an appropriate filter to discriminate against the background noise is presented. The problem of multiple images is discussed and a scheme for selecting diffraction geometry to eliminate unwanted images is presented. A detailed description of the relatively simple equipment used in Berg-Barrett work is given

    Effect of excited states and applied magnetic fields on the measured hole mobility in an organic semiconductor

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    Copyright 2010 by the American Physical Society. Article is available at
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