660 research outputs found

    Delayed feedback control of self-mobile cavity solitons in a wide-aperture laser with a saturable absorber

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    We investigate the spatiotemporal dynamics of cavity solitons in a broad area vertical-cavity surface-emitting laser with saturable absorption subjected to time-delayed optical feedback. Using a combination of analytical, numerical and path continuation methods we analyze the bifurcation structure of stationary and moving cavity solitons and identify two different types of traveling localized solutions, corresponding to slow and fast motion. We show that the delay impacts both stationary and moving solutions either causing drifting and wiggling dynamics of initially stationary cavity solitons or leading to stabilization of intrinsically moving solutions. Finally, we demonstrate that the fast cavity solitons can be associated with a lateral mode-locking regime in a broad-area laser with a single longitudinal mode

    Orbital Configurations and Magnetic Properties of Double-Layered Antiferromagnet Cs3_3Cu2_2Cl4_4Br3_3

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    We report the single-crystal X-ray analysis and magnetic properties of a new double-layered perovskite antiferromagnet, Cs3_3Cu2_2Cl4_4Br3_3. This structure is composed of Cu2_2Cl4_4Br3_3 double layers with elongated CuCl4_4Br2_2 octahedra and is closely related to the Sr3_3Ti2_2O7_7 structure. An as-grown crystal has a singlet ground state with a large excitation gap of Δ/kB2000\Delta/k_{\rm B}\simeq 2000 K, due to the strong antiferromagnetic interaction between the two layers. Cs3_3Cu2_2Cl4_4Br3_3 undergoes a structural phase transition at Ts330T_{\rm s}\simeq330 K accompanied by changes in the orbital configurations of Cu2+^{2+} ions. Once a Cs3_3Cu2_2Cl4_4Br3_3 crystal is heated above TsT_{\rm s}, its magnetic susceptibility obeys the Curie-Weiss law with decreasing temperature even below TsT_{\rm s} and does not exhibit anomalies at TsT_{\rm s}. This implies that in the heated crystal, the orbital state of the high-temperature phase remains unchanged below TsT_{\rm s}, and thus, this orbital state is the metastable state. The structural phase transition at TsT_{\rm s} is characterized as an order-disorder transition of Cu2+^{2+} orbitals.Comment: 6pages. 6figures, to appear in J. Phys. Soc. Jpn. Vol.76 No.

    In-Line-Test of Variability and Bit-Error-Rate of HfOx-Based Resistive Memory

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    Spatial and temporal variability of HfOx-based resistive random access memory (RRAM) are investigated for manufacturing and product designs. Manufacturing variability is characterized at different levels including lots, wafers, and chips. Bit-error-rate (BER) is proposed as a holistic parameter for the write cycle resistance statistics. Using the electrical in-line-test cycle data, a method is developed to derive BERs as functions of the design margin, to provide guidance for technology evaluation and product design. The proposed BER calculation can also be used in the off-line bench test and build-in-self-test (BIST) for adaptive error correction and for the other types of random access memories.Comment: 4 pages. Memory Workshop (IMW), 2015 IEEE Internationa

    About the origin of the acrocentric part of non-acrocentric satellited chromosomes in humans

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    Here we characterized 11 healthy carriers of a non-acrocentric satellited chromosomes der(A)t(A;acro)(pter or qter;p1?1.2) to determine the frequency of chromosome 15p and 22p in such rearrangement

    Health effects in fish of long-term exposure to effluents from wastewater treatment works

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    The effects of simple mixtures of chemicals, with similar mechanisms of action, can be predicted using the concentration addition model (CA). The ability of this model to predict the estrogenic effects of more complex mixtures such as effluent discharges, however, has yet to be established. Effluents from 43 U.K. wastewater treatment works were analyzed for the presence of the principal estrogenic chemical contaminants, estradiol, estrone, ethinylestradiol, and nonylphenol. The measured concentrations were used to predict the estrogenic activity of each effluent, employing the model of CA, based on the relative potencies of the individual chemicals in an in vitro recombinant yeast estrogen screen (rYES) and a short-term (14-day) in vivo rainbow trout vitellogenin induction assay. Based on the measured concentrations of the four chemicals in the effluents and their relative potencies in each assay, the calculated in vitro and in vivo responses compared well and ranged between 3.5 and 87 ng/L of estradiol equivalents (E2 EQ) for the different effluents. In the rYES, however, the measured E2 EQ concentrations in the effluents ranged between 0.65 and 43 ng E2 EQ/L, and they varied against those predicted by the CA model. Deviations in the estimation of the estrogenic potency of the effluents by the CA model, compared with the measured responses in the rYES, are likely to have resulted from inaccuracies associated with the measurement of the chemicals in the extracts derived from the complex effluents. Such deviations could also result as a consequence of interactions between chemicals present in the extracts that disrupted the activation of the estrogen response elements in the rYES. E2 EQ concentrations derived from the vitellogenic response in fathead minnows exposed to a series of effluent dilutions were highly comparable with the E2 EQ concentrations derived from assessments of the estrogenic potency of these dilutions in the rYES. Together these data support the use of bioassays for determining the estrogenic potency of WwTW effluents, and they highlight the associated problems for modeling approaches that are reliant on measured concentrations of estrogenic chemicals

    First molecular cytogenetic characterization of the MMT 060562 murine breast cancer cell line

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    To provide detailed cytogenetic characterization of the MMT 060562 cancer cell lin

    Spin Driven Jahn-Teller Distortion in a Pyrochlore system

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    The ground-state properties of the spin-1 antiferromagnetic Heisenberg model on the corner-sharing tetrahedra, pyrochlore lattice, is investigated. By breaking up each spin into a pair of 1/2-spins, the problem is reduced to the equivalent one of the spin-1/2 tetrahedral network in analogy with the valence bond solid state in one dimension. The twofold degeneracy of the spin-singlets of a tetrahedron is lifted by a Jahn-Teller mechanism, leading to a cubic to tetragonal structural transition. It is proposed that the present mechanism is responsible for the phase transition observed in the spin-1 spinel compounds ZnV2_2O4_4 and MgV2_2O4_4.Comment: 4 pages, 3 eps figures, REVTeX, to appear in Phys. Rev. Let
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