5,202 research outputs found

    Decentralised delay-dependent static output feedback variable structure control

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    In this paper, an output feedback stabilisation problem is considered for a class of large scale interconnected time delay systems with uncertainties. The uncertainties appear in both isolated subsystems and interconnections. The bounds on the uncertainties are nonlinear and time delayed. It is not required that either the known interconnections or the uncertain interconnections are matched. Then, a decentralised delay-dependant static output feedback variable structure control is synthesised to stabilise the system globally uniformly asymptotically using the Lyapunov Razumikhin approach. A case study relating to a river pollution control problem is presented to illustrate the proposed approach

    Magnonic band structure of domain wall magnonic crystals

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    Magnonic crystals are prototype magnetic metamaterials designed for the control of spin wave propagation. Conventional magnonic crystals are composed of single domain elements. If magnetization textures, such as domain walls, vortices and skyrmions, are included in the building blocks of magnonic crystals, additional degrees of freedom over the control of the magnonic band structure can be achieved. We theoretically investigate the influence of domain walls on the spin wave propagation and the corresponding magnonic band structure. It is found that the rotation of magnetization inside a domain wall introduces a geometric vector potential for the spin wave excitation. The corresponding Berry phase has quantized value 4nwπ4 n_w \pi, where nwn_w is the winding number of the domain wall. Due to the topological vector potential, the magnonic band structure of magnonic crystals with domain walls as comprising elements differs significantly from an identical magnonic crystal composed of only magnetic domains. This difference can be utilized to realize dynamic reconfiguration of magnonic band structure by a sole nucleation or annihilation of domain walls in magnonic crystals.Comment: 21 pages, 9 figure

    Systematic investigation of the rotational bands in nuclei with Z≈100Z \approx 100 using a particle-number conserving method based on a cranked shell model

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    The rotational bands in nuclei with Z≈100Z \approx 100 are investigated systematically by using a cranked shell model (CSM) with the pairing correlations treated by a particle-number conserving (PNC) method, in which the blocking effects are taken into account exactly. By fitting the experimental single-particle spectra in these nuclei, a new set of Nilsson parameters (κ\kappa and μ\mu) and deformation parameters (ε2\varepsilon_2 and ε4\varepsilon_4) are proposed. The experimental kinematic moments of inertia for the rotational bands in even-even, odd-AA and odd-odd nuclei, and the bandhead energies of the 1-quasiparticle bands in odd-AA nuclei, are reproduced quite well by the PNC-CSM calculations. By analyzing the ω\omega-dependence of the occupation probability of each cranked Nilsson orbital near the Fermi surface and the contributions of valence orbitals in each major shell to the angular momentum alignment, the upbending mechanism in this region is understood clearly.Comment: 21 pages, 24 figures, extended version of arXiv: 1101.3607 (Phys. Rev. C83, 011304R); added refs.; added Fig. 4 and discussions; Phys. Rev. C, in pres

    A Case-Based Reasoning Method for Remanufacturing Process Planning

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    Remanufacturing is a practice of growing importance due to its increasing environmental and economic benefits. Process planning plays a critical role in realizing a successful remanufacturing strategy. This paper presents a case-based reasoning method for remanufacturing process planning, which allows a process planner to rapidly retrieve, reuse, revise, and retain the solutions to past process problems. In the proposed method, influence factors including essential characteristics, failure characteristics, and remanufacturing processing characteristics are identified, and the local similarity of influence factors between the new case and the past cases is determined by nearest neighbor matching method, and then the vector of correction factor for local similarity is utilized in the nearest neighbor algorithm to improve the accuracy and effectiveness of case searching. To assess the usefulness and practicality of the proposed method, an illustrative example is given and the results are discussed

    Phylogeography and Demographic History of Chinese Black-Spotted Frog Populations (Pelophylax nigromaculata): Evidence for Independent Refugia Expansion and Secondary Contact

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    <p>Abstract</p> <p>Background</p> <p>Pleistocene glaciations had considerable impact on phylogeographic patterns within and among closely related species of many vertebrates. Compared to Europe and North America, research on the phylogeography of vertebrates in East Asia, particularly in China, remains limited. The black-spotted frog (<it>Pelophylax nigromaculata</it>) is a widespread species in East Asia. The wide distribution of this species in China makes it an ideal model for the study of palaeoclimatic effects on vertebrates in East Asia. Our previous studies of <it>P. nigromaculata </it>revealed significant subdivisions between the northeast China populations and populations in other regions of the mainland. In the present study, we aim to see whether the deepest splits among lineages and perhaps subsequent genealogical divisions are temporally consistent with a Pleistocene origin and whether clade geographic distributions, with insight into expansion patterns, are similarly spatially consistent with this model.</p> <p>Results</p> <p>Using 1143 nucleotides of the mitochondrial cytochrome <it>b </it>gene from 262 individuals sampled from 28 localities, two main clades (clade A and clade B) differing by <it>c</it>. 7.72% sequence divergence were defined from parsimony analyses. The corresponding timing of lineage divergence, 0.92 Mya, indicates a most likely Pleistocene split. The A clade is further subdivided into two sub-clades, A1 and A2 with 1.22% sequence divergence. Nested clade phylogeographical and population demographic analyses suggested that the current distribution of this frog species was the result of range expansion from two independent refugia during the last interglacial period. We discovered a population within which haplotype lineages A and B of <it>P. nigromaculata </it>coexist in the Dongliao area of China by nucleotide sequences, PCR-RFLP and ISSR (inter simple sequence repeat) patterns. The ISSR result in particular supported divergence between the mitochondrial clades A and B and implied introgressive gene flow between the two divergent lineages.</p> <p>Conclusion</p> <p>Nested clade phylogeographical and population demographic analyses indicate that the current distribution of <it>P. nigromaculata </it>is the result of range expansion from two independent refugia during the last interglacial period in late Pleistocene. One refugium was in east China and the lower elevations of south-western plateau. The distribution of the other mitochondrial clade is consistent with the presence of a refugium in the Korean Peninsula. The gene flow as detected by ISSR markers suggests a range expansion of the two refugia and a secondary contact between the two highly divergent lineages in the Dongliao (DL) area of northeast China.</p

    Rotation and alignment of high-jj orbitals in transfermium nuclei

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    The structure of nuclei with Z∼100Z\sim100 is investigated systematically by the Cranked Shell Model (CSM) with pairing correlations treated by a Particle-Number Conserving (PNC) method. In the PNC method, the particle number is conserved and the Pauli blocking effects are taken into account exactly. By fitting the experimental single-particle spectra in these nuclei, a new set of Nilsson parameters (κ\kappa and μ\mu) is proposed. The experimental kinematic moments of inertia and the band-head energies are reproduced quite well by the PNC-CSM calculations. The band crossing, the effects of high-jj intruder orbitals and deformation are discussed in detail.Comment: To appear in the Proceedings of the International Nuclear Physics Conference (INPC2013), June 2-7, 2013, Florence, Ital
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