14,226 research outputs found

    Growth, characterization, and waveguide lasing of Yb3+, Lu3+, Gd3+ co-doped KY(WO4)2 thin layers

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    Monoclinic crystals of KY(WO4)2 (KYW) doped with different rare-earth ions are among the highly promising materials for building compact solid-state lasers. \ud We report the liquid phase epitaxy (LPE) growth of 3-5 µm thick KYW:Gd3+, Lu3+, Yb3+ layers for Yb3+ concentrations of 1.2, 1.7, and 2.4 mol% and 30 to 40-µm-thick KYW:Gd3+, Yb3+ (20 mol%) layers. The concentration of the dopants Yb3+, Lu3+, and Gd3+ in the grown film were determined by laser ablation inductively coupled plasma - mass spectrometry (LA-ICP-MS). The growth conditions were optimized, leading to crack-free layers for all investigated Yb3+ concentrations. X-ray investigations have confirmed the high crystallinity of the films.\ud Based on the Gd3+, Lu3+ co-doped thin films, planar waveguide lasers operating on the Yb3+ transition at 1025 nm were demonstrated. Due to the co-doping, resulting in high refractive-index difference between film and substrate, very thin waveguides with strong light confinement were obtained, thus allowing for a pump threshold of laser operation as low as 18 mW. The highest slope efficiency versus absorbed pump power and output power were 82.3% and 195 mW, respectively

    A secondary ejecta explanation of a lunar seismogram

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    Secondary ejecta explanation to seismograph of Apollo 12 LM impac

    TM digital image products for applications

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    Computer compatible tapes (CCTs) of LANDSAT 4 thematic mapper (TM) digital image products are compared and reviewed. The following tape formats are discussed: (1) raw band-sequential data (CCT-BT); (2) calibrated data (CCT-AT); and (3) geometrically resampled data (CCT-PT). Each format represents different steps in the process of producing fully corrected TM data. The CCT-BT images are uncorrected radiometrically or geometrically, CCT-AT data are radiometrically calibrated, and CCT-PT images are both radiometrically and geometrically corrected

    TM digital image products for applications

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    The image characteristics of digital data generated by LANDSAT 4 thematic mapper (TM) are discussed. Digital data from the TM resides in tape files at various stages of image processing. Within each image data file, the image lines are blocked by a factor of either 5 for a computer compatible tape CCT-BT, or 4 for a CCT-AT and CCT-PT; in each format, the image file has a different format. Nominal geometric corrections which provide proper geodetic relationships between different parts of the image are available only for the CCT-PT. It is concluded that detector 3 of band 5 on the TM does not respond; this channel of data needs replacement. The empty bin phenomenon in CCT-AT images results from integer truncations of mixed-mode arithmetric operations

    Focusing a fountain of neutral cesium atoms with an electrostatic lens triplet

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    An electrostatic lens with three focusing elements in an alternating-gradient configuration is used to focus a fountain of cesium atoms in their ground (strong-field-seeking) state. The lens electrodes are shaped to produce only sextupole plus dipole equipotentials which avoids adding the unnecessary nonlinear forces present in cylindrical lenses. Defocusing between lenses is greatly reduced by having all of the main electric fields point in the same direction and be of nearly equal magnitude. The addition of the third lens gave us better control of the focusing strength in the two transverse planes and allowed focusing of the beam to half the image size in both planes. The beam envelope was calculated for lens voltages selected to produced specific focusing properties. The calculations, starting from first principles, were compared with measured beam sizes and found to be in good agreement. Application to fountain experiments, atomic clocks, and focusing polar molecules in strong-field-seeking states is discussed.Comment: 8 pages 10 figure

    Limit Pricing and Predation in the Antitrust Laws: Economic and Legal Aspects

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    The overwhelming view in the economic literature is that limit pricing, the practice of establishing a non-profit-maximizing price with the intention of deterring entry of others into the market, either does not make economic sense or, in any event, does not have anticompetitive effects. This article will take a systematic look at the legal status of the limit price doctrine and propose its proper role

    The calibration of photographic and spectroscopic films: Reciprocity failure and thermal responses of IIaO film at liquid nitrogen temperatures

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    Reciprocity failure was examined for IIaO spectroscopic film. The results indicate reciprocity failure occurs at three distinct minimum points in time; 15 min, 30 min and 90 min. The results are unique because theory suggests only one minimum reciprocity failure point should occur. When incubating 70mm IIaO film for 15 and 30 min at temperatures of 30, 40, 50, and 60 C and then placing in a liquid nitrogen bath at a temperature of -190 C the film demonstrated an increase of the optical density when developed at a warm-up time of 30 min. Longer warm-up periods of 1, 2 and 3 hrs yield a decrease in optical density of the darker wedge patterns; whereas, shorter warm-up times yield an overall increase in the optical densities

    Base hydrolysis of trans-dichlorodiammineplatinum (II)

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    The reactions t- [Pt(NH3)2Cl2 ] + OH- -\u3et- [Pt(NH3)2C1(OH) ] + CIt- [Pt(NH3) 2 Cl(OH)] + OH-- -\u3e t- [Pt(NH3) 2 (OH) 2 ] + Cl in aqueous solutions were studied by measuring the changes in specific conductivity and in ultraviolet absorption which occurred during the course of the reactions. The rates of reaction were determined from a plot of ln L(t) vs time, where L(t) is either (optical density at infinite time)( optical density at time t) for the spectrophotometric determinations or (conductivity at time t) - (conductivity at infinite time) for the conductometric experiments. The conductometric experiments also required correction for hydroxide attack upon the measuring vessel. Both reactions were found to be zero order in hydroxide, to be the only reactions occurring between the platinum complex and the hydroxide for times up to one day, and to involve the formation of an aquo intermediate. The rates for the first hydrolysis were 6. 21 x 10-5 sec -1- at 20 °C, 10. 6 x 10 -5 sec-1 at 25°C, and 29.3 x 10-5 sec-1 at 35°C, with an energy of activation of 18.0 kcal and an entropy of activation of -16 cal/ °K. The rates for the second hydrolysis were 0.17 x 10-5 sec-1 at 25°C and 0. 50 x 10-5 sec-1 at 35°C, with an energy activation of 19.1 kcal and an entropy of activation of -21 cal/ °K

    Towards the QCD phase diagram from analytical continuation

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    We calculate the QCD cross-over temperature, the equation of state and fluctuations of conserved charges at finite density by analytical continuation from imaginary to real chemical potentials. Our calculations are based on new continuum extrapolated lattice simulations using the 4stout staggered actions with a lattice resolution up to Nt=16N_t=16. The simulation parameters are tuned such that the strangeness neutrality is maintained, as it is in heavy ion collisions.Comment: 4 pages, 2 figures, Proceedings of the Quark Matter 2015 conference, Kobe, Japa

    Relative entropy as a measure of inhomogeneity in general relativity

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    We introduce the notion of relative volume entropy for two spacetimes with preferred compact spacelike foliations. This is accomplished by applying the notion of Kullback-Leibler divergence to the volume elements induced on spacelike slices. The resulting quantity gives a lower bound on the number of bits which are necessary to describe one metric given the other. For illustration, we study some examples, in particular gravitational waves, and conclude that the relative volume entropy is a suitable device for quantitative comparison of the inhomogeneity of two spacetimes.Comment: 15 pages, 7 figure
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