1,217 research outputs found

    Phase cascade bridge rectifier array in a 2-D lattice

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    We report on a novel rectification phenomenon in a 2-D lattice network consisting of N×N sites with diode and AC source elements with controllable phases. A phase cascade configuration is described in which the current ripple in a load resistor goes to zero in the large N limit, enhancing the rectification efficiency without requiring any external capacitor or inductor based filters. The integrated modular configuration is qualitatively different from conventional rectenna arrays in which the source, rectifier and filter systems are physically disjoint. Exact analytical results derived using idealized diodes are compared to a realistic simulation of commercially available diodes. Our results on nonlinear networks of source-rectifier arrays are potentially of interest to a fast evolving field of distributed power networks

    10-Gb/s transmission over 20-km single fiber link using 1-GHz RSOA by discrete multitone with multiple access

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    We demonstrate a novel 10.5-Gbit/s transmission scheme over 20-km single fiber link by using a remotely fed 1-GHz reflective semiconductor optical amplifier (RSOA). Discrete multitone (DMT) modulation with adaptive bit-/power-loading is applied to overcome the bandwidth limitation of the RSOA. Transmission performance of the proposed scheme is analyzed in terms of various system parameters, such as the nonlinearity of the RSOA, optical signal-to-noise ratio of the optical seed carrier, the overhead size impact on dispersion, the number of DMT subcarriers, and the reflection noise from the single fiber link. We also report flexible-bandwidth-allocated multiple access operation based on the proposed scheme. The throughput for all cases is approximately 10 Gbit/s with BER <10-3

    The signal of Z±(4430)Z^\pm(4430) in nucleon-antinucleon scattering

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    We study the production of Z±(4430)Z^\pm(4430) at a nucleon-antinucleon scattering experiment. Considering the PANDA experiment to be an ideal platform to explore the production of the charmonium and charmonim-like states, we suggest the forthcoming PANDA experiment to pay attention to the production of Z±(4430)Z^\pm(4430).Comment: 6 pages, 15 figures. Published version in EPJ

    Parametric pumping at finite frequency

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    We report on a first principles theory for analyzing the parametric electron pump at a finite frequency. The pump is controlled by two pumping parameters with phase difference ϕ\phi. In the zero frequency limit, our theory predicts the well known result that the pumped current is proportional to sinâĄÏ•\sin\phi. For the more general situation of a finite frequency, our theory predicts a non-vanishing pumped current even when the two driving forces are in phase, in agreement with the recent experimental results. We present the physical mechanism behind the nonzero pumped current at ϕ=0\phi=0, which we found to be due to photon-assisted processes

    Synchronization in a System of Globally Coupled Oscillators with Time Delay

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    We study the synchronization phenomena in a system of globally coupled oscillators with time delay in the coupling. The self-consistency equations for the order parameter are derived, which depend explicitly on the amount of delay. Analysis of these equations reveals that the system in general exhibits discontinuous transitions in addition to the usual continuous transition, between the incoherent state and a multitude of coherent states with different synchronization frequencies. In particular, the phase diagram is obtained on the plane of the coupling strength and the delay time, and ubiquity of multistability as well as suppression of the synchronization frequency is manifested. Numerical simulations are also performed to give consistent results

    The BPS Domain Wall Solutions in Self-Dual Chern-Simons-Higgs Systems

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    We study domain wall solitons in the relativistic self-dual Chern-Simons Higgs systems by the dimensional reduction method to two dimensional spacetime. The Bogomolny bound on the energy is given by two conserved quantities in a similar way that the energy bound for BPS dyons is set in some Yang-Mills-Higgs systems in four dimensions. We find the explicit soliton configurations which saturate the energy bound and their nonrelativistic counter parts. We also discuss the underlying N=2 supersymmetry.Comment: 16 pages, LaTeX, no figure, a minor change in acknowledgment

    Comparative transcriptome analysis identified candidate genes for late leaf spot resistance and cause of defoliation in groundnut

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    Late leaf spot (LLS) caused by fungus Nothopassalora personata in groundnut is responsible for up to 50% yield loss. To dissect the complex nature of LLS resistance, comparative transcriptome analysis was performed using resistant (GPBD 4), susceptible (TAG 24) and a resistant introgression line (ICGV 13208) and identified a total of 12,164 and 9954 DEGs (differentially expressed genes) respectively in A- and B-subgenomes of tetraploid groundnut. There were 135 and 136 unique pathways triggered in A- and B-subgenomes, respectively, upon N. personata infection. Highly upregulated putative disease resistance genes, an RPP-13 like (Aradu.P20JR) and a NBS-LRR (Aradu.Z87JB) were identified on chromosome A02 and A03, respectively, for LLS resistance. Mildew resistance Locus (MLOs)-like proteins, heavy metal transport proteins, and ubiquitin protein ligase showed trend of upregulation in susceptible genotypes, while tetratricopeptide repeats (TPR), pentatricopeptide repeat (PPR), chitinases, glutathione S-transferases, purple acid phosphatases showed upregulation in resistant genotypes. However, the highly expressed ethylene responsive factor (ERF) and ethylene responsive nuclear protein (ERF2), and early responsive dehydration gene (ERD) might be related to the possible causes of defoliation in susceptible genotypes. The identified disease resistance genes can be deployed in genomics-assisted breeding for development of LLS resistant cultivars to reduce the yield loss in groundnut

    The AdS/QCD Correspondence: Still Undelivered

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    We consider the particle spectrum and event shapes in large N gauge theories in different regimes of the short-distance 't Hooft coupling, lambda. The mesons in the small lambda limit should have a Regge spectrum in order to agree with perturbation theory, while generically the large lambda theories with gravity duals produce spectra reminiscent of KK modes. We argue that these KK-like states are qualitatively different from QCD modes: they are deeply bound states which are sensitive to short distance interactions rather than the flux tube-like states expected in asymptotically free, confining gauge theories. In addition, we also find that the characteristic event shapes for the large lambda theories with gravity duals are close to spherical, very different from QCD-like (small lambda, small N) and Nambu-Goto-like (small lambda, large N) theories which have jets. This observation is in agreement with the conjecture of Strassler on event shapes in large 't Hooft coupling theories, which was recently proved by Hofman and Maldacena for the conformal case. This conclusion does not change even when considering soft-wall backgrounds in the gravity dual. The picture that emerges is the following: theories with small and large lambda are qualitatively different, while theories with small and large N are qualitatively similar. Thus it seems that it is the relative smallness of the 't Hooft coupling in QCD that prevents a reliable AdS/QCD correspondence from emerging, and that reproducing characteristic QCD-like behavior will require genuine stringy dynamics to be incorporated into any putative dual theory.Comment: 32 pages, 15 figures; references added, minor changes, history clarifie

    Pseudogap formation of four-layer BaRuO3_3 and its electrodynamic response changes

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    We investiaged the optical properties of four-layer BaRuO3_{3}, which shows a fermi-liquid-like behavior at low temperature. Its optical conductivity spectra clearly displayed the formation of a pseudogap and the development of a coherent peak with decreasing temperature. Temperature-dependences of the density nn and the scattering rate 1/τ1/\tau of the coherent component were also derived. As the temperature decreases, both nn and 1/τ1/\tau decrease for four-layer BaRuO3_{3}. These electrodynamic responses were compared with those of nine-layer BaRuO3_{3}, which also shows a pseudogap formation but has an insulator-like state at low temperature. It was found that the relative rates of change of both nn and 1/τ1/\tau determine either metallic or insulator-like responses in the ruthenates. The optical properties of the four-layer ruthenate were also compared with those of other pseudogap systems, such as high TcT_{c} cuprates and heavy electron systems.Comment: 7 figures. submitted to Phys. Rev.
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