1,108 research outputs found

    Description of self-synchronization effects in distributed Josephson junction arrays using harmonic analysis and power balance

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    Power generation and synchronisation in Josephson junction arrays have attracted attention for a long time. This stems from fundamental interest in nonlinear coupled systems as well as from potential in practical applications. In this paper we study the case of an array of junctions coupled to a distributed transmission line either driven by an external microwave or in a self-oscillating mode. We simplify the theoretical treatment in terms of harmonic analysis and power balance. We apply the model to explain the large operation margins of SNS- and SINIS-junction arrays. We show the validity of the approach by comparing with experiments and simulations with self-oscillating es-SIS junction arrays.Comment: 5 pages, 3 figure

    An Analytical Evaluation of Distortion-Induced Fatigue in Steel Bridges

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    Multi-girder steel bridges designed prior to the mid-1980's, have developed cracks due to distortion-induced fatigue. An analytical evaluation was conducted to better understand the effects of bridge configurations and common retrofits on distortion-induced fatigue, as quantified by hot spot stress in web gap regions. Results are described herein and present relative distortion-induced fatigue susceptibility of multi-girder bridges with varied skew angle, cross frame spacing, bracing configuration, and cross frame stiffness as well as regions within each variation where cracking is most likely to occur. Performance of retrofit techniques was also compared and included positive attachment, a slotted connection stiffener, a back-up stiffener, and cross frame removal with each implemented both locally and globally. In addition, influence surfaces were generated and analyzed for three bridge configurations to better understand the relationship between load placement and distortion-induced fatigue related stresses. It is hoped that this research will benefit bridge engineers working to identify and extend the fatigue life of bridges susceptible to distortion-induced fatigue

    Nondestructive Ultrasonic Characterization of the Orientation Distribution of Short-Fiber Composites

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    The ease of fabrication and relatively low cost of composites containing short glass or ceramic fibers embedded in a polymer or metal matrix has made them attractive candidates for a wide range of applications. The preferential alignment, or misalignment depending on one’s view, of the short fibers results in an overall texture of the composite and strongly influences its mechanical and physical response, for example, stiffness, conductivity, strength, and so on. The orientation of the short fibers depends strongly on the processing conditions. From a process-control viewpoint, it is imperative to determine if a composite component has adequate strength, stiffness, and so on, and it is preferable to obtain this information nondestructively. In short-fiber reinforced composites, the orientation distribution of the short fibers is the most significant variable that determines these overall properties. Thus its determination is essential

    Monopolelike probes for quantitative magnetic force microscopy: calibration and application

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    A local magnetization measurement was performed with a Magnetic Force Microscope (MFM) to determine magnetization in domains of an exchange coupled [Co/Pt]/Co/Ru multilayer with predominant perpendicular anisotropy. The quantitative MFM measurements were conducted with an iron filled carbon nanotube tip, which is shown to behave like a monopole. As a result we determined an additional in-plane magnetization component of the multilayer, which is explained by estimating the effective permeability of the sample within the \mu*-method.Comment: 3 pages, 3 figure

    RSFQ devices with selective dissipation for quantum information processing

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    We study the possibility to use frequency dependent damping in RSFQ circuits as means to reduce dissipation and consequent decoherence in RSFQ/qubit circuits. We show that stable RSFQ operation can be achieved by shunting the Josephson junctions with an RCRC circuit instead of a plain resistor. We derive criteria for the stability of such an arrangement, and discuss the effect on decoherence and the optimisation issues. We also design a simple flux generator aimed at manipulating flux qubits

    First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of 163^{163}Ho

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    The isotope 163^{163}Ho undergoes an electron capture process with a recommended value for the energy available to the decay, QECQ_{\rm EC}, of about 2.5 keV. According to the present knowledge, this is the lowest QECQ_{\rm EC} value for electron capture processes. Because of that, 163^{163}Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the 163^{163}Dy daughter atom upon the capture of an electron from the 5s shell in 163^{163}Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the 163^{163}Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of 163^{163}Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we discuss the implications of this result for the Electron Capture 163^{163}Ho experiment, ECHo, aiming to reach sub-eV sensitivity on the electron neutrino mass by a high precision and high statistics calorimetric measurement of the 163^{163}Ho spectrum.Comment: 5 pages, 3 figure

    Herschel observations of EXtra-Ordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey Toward Orion KL II. Chemical Implications

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    We present chemical implications arising from spectral models fit to the Herschel/HIFI spectral survey toward the Orion Kleinmann-Low nebula (Orion KL). We focus our discussion on the eight complex organics detected within the HIFI survey utilizing a novel technique to identify those molecules emitting in the hottest gas. In particular, we find the complex nitrogen bearing species CH3_{3}CN, C2_{2}H3_{3}CN, C2_{2}H5_{5}CN, and NH2_{2}CHO systematically trace hotter gas than the oxygen bearing organics CH3_{3}OH, C2_{2}H5_{5}OH, CH3_{3}OCH3_{3}, and CH3_{3}OCHO, which do not contain nitrogen. If these complex species form predominantly on grain surfaces, this may indicate N-bearing organics are more difficult to remove from grain surfaces than O-bearing species. Another possibility is that hot (Tkin_{\rm kin}∼\sim300 K) gas phase chemistry naturally produces higher complex cyanide abundances while suppressing the formation of O-bearing complex organics. We compare our derived rotation temperatures and molecular abundances to chemical models, which include gas-phase and grain surface pathways. Abundances for a majority of the detected complex organics can be reproduced over timescales ≳\gtrsim 105^{5} years, with several species being under predicted by less than 3σ\sigma. Derived rotation temperatures for most organics, furthermore, agree reasonably well with the predicted temperatures at peak abundance. We also find that sulfur bearing molecules which also contain oxygen (i.e. SO, SO2_{2}, and OCS) tend to probe the hottest gas toward Orion KL indicating the formation pathways for these species are most efficient at high temperatures.Comment: 31 pages, 6 figures, 1 Table, accepted to the Astrophysical Journa

    Client Weight as a Barrier to Non-Biased Clinical Judgment

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    A sample of 95 Christian and 68 Non-Christian mental health professionals were given a picture of either an overweight or average-weight male or female client and a generic case vignette. Participants were asked to make clinical judgments of pathology and client attributions for the pictured client. Results indicated that mental health professionals ascribe more pathology and negative attributes to obese clients than to average-weight clients. In addition, Christian mental health professionals are just as likely as non-Christians to ascribe more negative attributes to obese clients. Ways to remove barriers to unbiased psychotherapy and deal with countertransference issues are discussed from a Christian perspective
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