Nonlinear characterization of a bistable energy harvester dynamical system

International audienceThis chapter explores the nonlinear dynamics of a piezo-magneto-elastic bistable energy device system regards the influence of external forcing parameters influence on system response. Time series, Poincaré maps, phase space trajectories, and bifurcation diagrams are employed in order to reveals system dynamics complexity and nonlinear effects, such as chaos incidence and hysteresis

Measurement of the Spectroscopy of Orbitally Excited B Mesons at LEP

We measure the masses, decay widths and relative production rate of orbitally excited B mesons using 1.25 million hadronic Z decays recorded by the L3 detector. B-meson candidates are inclusively reconstructed and combined with charged pions produced at the primary event vertex. An excess of events above the expected background in the B\pi mass spectrum in the region 5.6-5.8 GeV is interpreted as resulting from the decay B_u,d^** -> B^(*)\pi, where B_u,d^** denotes a mixture of l=1 B-meson states containing a u or a d quark. A fit to the mass spectrum yields the masses and decay widths of the B_1^* and B_2^* spin states, as well as the branching fraction for the combination of l=1 states. In addition, evidence is presented for the existence of an excited B-meson state or mixture of states in the region 5.9-6.0 GeV

Operation and performance of the ATLAS semiconductor tracker

The semiconductor tracker is a silicon microstrip detector forming part of the inner tracking system of the ATLAS experiment at the LHC. The operation and performance of the semiconductor tracker during the first years of LHC running are described. More than 99% of the detector modules were operational during this period, with an average intrinsic hit efficiency of (99.74±0.04)%. The evolution of the noise occupancy is discussed, and measurements of the Lorentz angle, δ-ray production and energy loss presented. The alignment of the detector is found to be stable at the few-micron level over long periods of time. Radiation damage measurements, which include the evolution of detector leakage currents, are found to be consistent with predictions and are used in the verification of radiation background simulations

Nonlinear optics and saturation behavior of quantum dot samples under continuous wave driving

The nonlinear optical response of self-assembled quantum dots is relevant to the application of quantum dot based devices in nonlinear optics, all-optical switching, slow light and self-organization. Theoretical investigations are based on numerical simulations of a spatially and spectrally resolved rate equation model, which takes into account the strong coupling of the quantum dots to the carrier reservoir created by the wetting layer states. The complex dielectric susceptibility of the ground state is obtained. The saturation is shown to follow a behavior in between the one for a dominantly homogeneously and inhomogeneously broadened medium. Approaches to extract the nonlinear refractive index change by fringe shifts in a cavity or self-lensing are discussed. Experimental work on saturation characteristic of InGa/GaAs quantum dots close to the telecommunication O-band (1.24-1.28 mm) and of InAlAs/GaAlAs quantum dots at 780 nm is described and the first demonstration of the cw saturation of absorption in room temperature quantum dot samples is discussed in detail

The BioPAX community standard for pathway data sharing

Biological Pathway Exchange (BioPAX) is a standard language to represent biological pathways at the molecular and cellular level and to facilitate the exchange of pathway data. The rapid growth of the volume of pathway data has spurred the development of databases and computational tools to aid interpretation; however, use of these data is hampered by the current fragmentation of pathway information across many databases with incompatible formats. BioPAX, which was created through a community process, solves this problem by making pathway data substantially easier to collect, index, interpret and share. BioPAX can represent metabolic and signaling pathways, molecular and genetic interactions and gene regulation networks. Using BioPAX, millions of interactions, organized into thousands of pathways, from many organisms are available from a growing number of databases. This large amount of pathway data in a computable form will support visualization, analysis and biological discovery. © 2010 Nature America, Inc. All rights reserved