1,759 research outputs found

    Effect of Yttrium substitution on superconductivity in Bi-2212 textured rods prepared by a LFZ technique

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    In this study, the physical and superconducting properties of the Bi2Sr2Ca1-xYxCu2O8+delta with x=0.0, 0.05, 0.075 0.1, and 0.20 textured superconducting rods prepared by a laser floating zone technique were presented. The effects of Y3+ substitution for Ca2+ have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), dc-magnetization, magnetic hysteresis and critical current density calculation by using the Bean''s critical state model. The powder XRD patterns of the samples have shown the Bi-2212 phase is the major one. Along with the powder samples, the textured rod surfaces also were investigated by XRD. The grains found to be well-oriented along the longitudinal rod axis which is a typical result for superconductors prepared by laser floating zone (LFZ) method, has been observed. The best critical temperature, T-C, has been found as 92.9 K for the sample with 0.15Y substitution, under DC magnetic field of 50 Oe in ZFC mode. It has also been observed that the critical current density decreases with increasing Y-substitution. Using those values, the maximum J(C) value has been determined as 2.37 x 10(5) A/cm(2) for the undoped sample

    Two-loop master integrals for pseudo-scalar quarkonium and leptonium production and decay

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    We compute the master integrals relevant for the two-loop corrections to pseudo-scalar quarkonium and leptonium production and decay. We present both analytic and high-precision numerical results. The analytic expressions are given in terms of multiple polylogarithms (MPLs), elliptic multiple polylogarithms (eMPLs) and iterated integrals of Eisenstein series. As an application of our results, we obtain for the first time an analytic expression for the two-loop amplitude for para-positronium decay to two photons at two loops

    Two-loop master integrals for pseudo-scalar quarkonium and leptonium production and decay

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    We compute the master integrals relevant for the two-loop corrections to pseudo-scalar quarkonium and leptonium production and decay. We present both analytic and high-precision numerical results. The analytic expressions are given in terms of multiple polylogarithms (MPLs), elliptic multiple polylogarithms (eMPLs) and iterated integrals of Eisenstein series. As an application of our results, we obtain for the first time an analytic expression for the two-loop amplitude for para-positronium decay to two photons at two loops

    An Overview and Assessment of Wireless Technologies and Co- existence of ZigBee, Bluetooth and Wi-Fi Devices

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    AbstractWi-Fi, ZigBee and Bluetooth wireless communication systems utilize the Industrial Scientific and Medical-(ISM) Band, which results in a high mutual interference between these technologies since they all these systems operate at the same or very close frequency bands. The interference problem increases with an in-device Co-existence (technologies existing on same device). This is primarily due to the characteristics of each technology such as access mechanism, frame structure, peak transmit power and frequency of operation. This work describes the interference between the Wi-Fi mostly as an aggressor on Bluetooth and ZigBee wireless networks. So the experimental analysis of the coexistence of these three technologies in an assumed home environment is studied especially when ZigBee is enabled for a Home Automation Network where there could be close proximity of Wi-Fi and Bluetooth devices such as PDAs and mobile phones. The obtained result shows that there is severe degradation on ZigBee and Bluetooth packet transmission of packets as well as re-transmission of ZigBee packets when Wi-Fi is operating

    Electronic transport characterization of AlGaN/GaN heterostructures using quantitative mobility spectrum analysis

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    Cataloged from PDF version of article.Resistivity and Hall effect measurements in nominally undoped Al0.25Ga0.75N/GaN heterostructures grown on sapphire substrate by metal-organic chemical vapor deposition are carried out as a function of temperature (20-350 K) and magnetic field (0-1.5 T). The measurement results are analyzed using the quantitative mobility spectrum analysis techniques. It is found that there is strong two-dimensional electron gas localization below 100 K, while the thermally activated minority carriers with the activation energies of similar to 58 and similar to 218 meV contribute to the electron transport at high temperatures. (C) 2007 American Institute of Physics

    Energy Efficient IP-Connectivity with IEEE 802.11 for Home M2M Networks

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    Machine-to-machine communication (M2M) technology enables large-scale device communication and networking, including home devices and appliances. A critical issue for home M2M networks is how to efficiently integrate existing home consumer devices and appliances into an IP-based wireless M2M network with least modifications. Due to its popularity and widespread use in closed spaces, Wi-Fi is a good alternative as a wireless technology to enable M2M networking for home devices. This paper addresses the energy-efficient integration of home appliances into a Wi-Fi- and IP-based home M2M network. Toward this goal, we first propose an integration architecture that requires least modifications to existing components. Then, we propose a novel long-term sleep scheduling algorithm to be applied with the existing 802.11 power save mode. The proposed scheme utilizes the multicast DNS protocol to maintain device and service availability when devices go into deep sleep mode. We prototyped our proposed architecture and algorithm to build a M2M network testbed of home appliances. We performed various experiments on this testbed to evaluate the operation and energy savings of our proposal. We also did simulation experiments for larger scale scenarios. As a result of our test-bed and simulation experiments, we observed significant energy savings compared to alternatives while also ensuring device and service availability. © The British Computer Society 2017. All rights reserved

    Missense mutation in the ATPase, aminophospholipid transporter protein ATP8A2 is associated with cerebellar atrophy and quadrupedal locomotion

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    Cataloged from PDF version of article.Cerebellar ataxia, mental retardation and dysequilibrium syndrome is a rare and heterogeneous condition. We investigated a consanguineous family from Turkey with four affected individuals exhibiting the condition. Homozygosity mapping revealed that several shared homozygous regions, including chromosome 13q12. Targeted next-generation sequencing of an affected individual followed by segregation analysis, population screening and prediction approaches revealed a novel missense variant, p.I376M, in ATP8A2. The mutation lies in a highly conserved C-terminal transmembrane region of E1 E2 ATPase domain. The ATP8A2 gene is mainly expressed in brain and development, in particular cerebellum. Interestingly, an unrelated individual has been identified, in whom mental retardation and severe hypotonia is associated with a de novo t(10;13) balanced translocation resulting with the disruption of ATP8A2. These findings suggest that ATP8A2 is involved in the development of the cerebro-cerebellar structures required for posture and gait in humans. © 2013 Macmillan Publishers Limited All rights reserved
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