178 research outputs found

    Breathing multichimera states in nonlocally coupled phase oscillators

    Get PDF
    Chimera states for the one-dimensional array of nonlocally coupled phase oscillators in the continuum limit are assumed to be stationary states in most studies, but a few studies report the existence of breathing chimera states. We focus on multichimera states with two coherent and incoherent regions, and numerically demonstrate that breathing multichimera states, whose global order parameter oscillates temporally, can appear. Moreover, we show that the system exhibits a Hopf bifurcation from a stationary multichimera to a breathing one by the linear stability analysis for the stationary multichimera.Comment: 8 pages, 9 figures. Fixed a typo in the published versio

    Persistent chimera states in nonlocally coupled phase oscillators

    Get PDF
    Chimera states in the systems of nonlocally coupled phase oscillators are considered stable in the continuous limit of spatially distributed oscillators. However, it is reported that in the numerical simulations without taking such limit, chimera states are chaotic transient and finally collapse into the completely synchronous solution. In this paper, we numerically study chimera states by using the coupling function different from the previous studies and obtain the result that chimera states can be stable even without taking the continuous limit, which we call the persistent chimera state.Comment: To be published in Physical Review E (Rapid Communication), 5 pages, 7 figure

    Emergence of second coherent regions for breathing chimera states

    Get PDF
    Chimera states in one-dimensional nonlocally coupled phase oscillators are mostly assumed to be stationary, but breathing chimeras can occasionally appear, branching from the stationary chimeras via Hopf bifurcation. In this paper, we demonstrate two types of breathing chimeras: The type I breathing chimera looks the same as the stationary chimera at a glance, while the type II consists of multiple coherent regions with different average frequencies. Moreover, it is shown that the type I changes to the type II by increasing the breathing amplitude. Furthermore, we develop a self-consistent analysis of the local order parameter, which can be applied to breathing chimeras, and numerically demonstrate this analysis in the present system.Comment: 11 pages, 10 figure

    Two dimensional anomalous small-angle scattering measurements at the Mg K absorption edge for nanostructure analysis in concentrated Al-Mg alloys

    Get PDF
    Two dimensional anomalous small-angle scattering measurement at K absorption edge of Mg has been successfully demonstrated for concentrated Al-Mg binary alloys and MgO nanoparticles. Enhancing the contrast between Mg-rich precipitates and Al matrix was explained by the anomalous dispersion of Mg, and anisotropic SAXS pattern was in good agreement with the microstructure observed by transmission electron microscopy. Agreement of atomic scattering factor obtained from Al-Mg and MgO nanoparticles indicates that the origin of SAXS in the present Al-Mg alloys are Guinier-Preston zones, not the voids that grew from supersaturated vacancies

    A Trial on Detecting Fluctuations in Bulk Metallic Glass Beams by Strain Contrast Variation Method-Use of High Energy Small-Angle Scattering

    Get PDF
    Heterogeneity in annealed Zr-Cu-Al alloys with high ductility has been examined by high-energy small-angle scattering with strain variation method. Although the statistics is still poor for detailed analysis, it was found that the heterogeneity in the sample showed clear enhancement by applied tensile strain, and the characteristic size of the heterogeneity was of the same order of magnitude as the one observed by high resolution electron microscopy. With surface insensitivity of the present method, anomalous small-angle scattering results at Cu K absorption edge for the same sample was briefly discussed

    Chemical speciation of water-soluble ionic components in PM2.5 derived from peatland fires in Sumatra Island

    Get PDF
    We conducted a field study to characterize water-soluble ionic species in PM2.5 from peatland fires using ground-based samplings at fire sources and receptor sites in the Riau Province, Sumatra, Indonesia. We determined the concentrations of PM2.5 mass, water-soluble ions, and some chemical elements. Through PM2.5 field samplings at three peatland fire sources, we have shown that the mass fractions of typical peatland fire water-soluble ionic components tend to differ between peatland fire sources. Thus, our results indicate that PM2.5 source profiles of water-soluble ionic components for peatland fire must be selected with extreme caution if applied to a receptor model. From the viewpoint of ionic composition of each peatland fire sample, Cl− and NH4+ were consistently dominant anions and cations, respectively, for all peatland fire samples, i.e., NH4Cl was a consistently dominant component. Through field samplings of the ambient PM2.5 in Pekanbaru during peatland fire-induced haze and non-haze periods, we found differences in PM2.5 mass and total water-soluble ionic component concentrations between haze and non-haze samples. Four components, C2O42−, NO3−, SO42−, and NH4+, showed highly elevated levels during haze periods. Since these four ions are recognized as the major secondarily formed aerosol components, the increased total concentrations of water-soluble ionic components during haze periods can mainly be derived from the gas-to-aerosol conversion process. The ionic compositions of haze samples at receptor sites are obviously different from those at peatland fire source samples. In particular, NH4Cl, which is characteristic of peatland fire PM2.5 sources, is low at sites during haze periods

    Chemical speciation of water-soluble ionic components in PM2.5 derived from peatland fires in Sumatra Island

    Get PDF
    We conducted a field study to characterize water-soluble ionic species in PM2.5 from peatland fires using groundbased samplings at fire sources and receptor sites in the Riau Province, Sumatra, Indonesia. We determined the concentrations of PM2.5 mass, water-soluble ions, and some chemical elements. Through PM2.5 field samplings at three peatland fire sources, we have shown that the mass fractions of typical peatland fire water-soluble ionic components tend to differ between peatland fire sources. Thus, our results indicate that PM2.5 source profiles of water-soluble ionic components for peatland fire must be selected with extreme caution if applied to a receptor model. From the viewpoint of ionic composition of each peatland fire sample, Cl− and NH4+ were consistently dominant anions and cations, respectively, for all peatland fire samples, i.e., NH4Cl was a consistently dominant component. Through field samplings of the ambient PM2.5 in Pekanbaru during peatland fire-induced haze and non-haze periods, we found differences in PM2.5 mass and total water-soluble ionic component concentrations between haze and non-haze samples. Four components, C2O42−, NO3−, SO42−, and NH4+, showed highly elevated levels during haze periods. Since these four ions are recognized as the major secondarily formed aerosol components, the increased total concentrations of water-soluble ionic components during haze periods can mainly be derived from the gas-to-aerosol conversion process. The ionic compositions of haze samples at receptor sites are obviously different from those at peatland fire source samples. In particular, NH4Cl, which is characteristic of peatland fire PM2.5 sources, is low at sites during haze period

    Absolute measurements of anomalous small-angle X-ray scattering intensity using glassy carbon at the Mg K absorption edge

    Get PDF
    Absolute measurements of small-angle X-ray scattering (SAXS) intensities at the K absorption edge of Mg have been performed using glassy carbon as an intensity standard. Glassy carbon samples polished down to give appropriate transmission have been prepared as a secondary standard to be used at 1.3 keV. Al–Mg binary alloys were used to assess the metastable phase boundary for the Al3Mg metastable precipitation from the absolute scattering intensity. The assessed phase boundary agreed with the previous reports. Glassy carbon was concluded to be an appropriate candidate for an intensity standard sample for transmission measurements of SAXS in the tender X-ray regions
    corecore