Dynamical response of fractional-order nonlinear system with combined parametric and forcing excitation

A dynamical analysis of a Mathieu-van der Pol-Duffing nonlinear system with fractional-order derivative under combined parametric and forcing excitation is studied in this paper. The approximate analytical solution is researched for 1/2 sub harmonic resonance coupled with primary parametric resonance based on the improved averaging approach. The steady-state periodic solution including its stability condition is established. The equivalent linear stiffness coefficient (ELDC) and equivalent linear damping coefficient (ELSC) for this nonlinear fractional-order oscillator are defined. Then, the numerical simulations are presented in three typical cases by iterative algorithms. The time history, phase portrait, FFT spectrum and Poincare maps are shown to explain the system response. Some different responses, such as quasi-periodic, multi-periodic and single periodic behaviors are observed and investigated. The results of comparisons between the numerical solutions and the approximate analytical solutions in three typical cases show the correctness of the analytical solutions. The influences of the fractional-order parameters on the system dynamical response are researched based on the ELDC and ELSC. Through analysis, it could be found that the increase of the fractional-order coefficient would result in the rightward and downward movements of the amplitude-frequency curves. The increase of the fractional-order coefficient will also move the bifurcation point rightwards and will make the existing range of steady-state solution larger. It could also be found that the ELSC will become larger and ELDC smaller when the fractional order is closer to zero, so that the decrease of the fractional order would make the response amplitude larger. At last, the detailed conclusions are summarized, which is beneficial to design and control this kind of fractional-order nonlinear system

Observation of spin-orbit magnetoresistance in metallic thin films on magnetic insulators

A magnetoresistance effect induced by the Rashba spin-orbit interaction was predicted, but not yet observed, in bilayers consisting of normal metal and ferromagnetic insulator. Here, we present an experimental observation of this new type of spin-orbit magnetoresistance (SOMR) effect in a bilayer structure Cu[Pt]/Y3Fe5O12 (YIG), where the Cu/YIG interface is decorated with nanosize Pt islands. This new MR is apparently not caused by the bulk spin-orbit interaction because of the negligible spin-orbit interaction in Cu and the discontinuity of the Pt islands. This SOMR disappears when the Pt islands are absent or located away from the Cu/YIG interface, therefore we can unambiguously ascribe it to the Rashba spin-orbit interaction at the interface enhanced by the Pt decoration. The numerical Boltzmann simulations are consistent with the experimental SOMR results in the angular dependence of magnetic field and the Cu thickness dependence. Our finding demonstrates the realization of the spin manipulation by interface engineering.Comment: 12 pages, 4 figures, 14 pages in supplementary. To appear on Science Advance

Orthotopic and heterotopic tracheal transplantation model in studying obliterative bronchiolitis

AbstractBackgroundSeveral animal models have been established to investigate the mechanisms of obliterative bronchiolitis after lung transplantation. In this study, we compared three prevalent murine models of obliterative bronchiolitis in terms of several basic pathologic changes in a relatively short span of time after transplantation.MethodsEach of the recipient mice simultaneously received orthotopic, intra-omental and subcutaneous tracheal transplantation in both syngeneic and allogeneic settings. No immunosuppressive treatment was administered. Tracheal grafts were harvested on Day 14, 21 and 28 after transplantation for histological and immunohistochemical analyses.ResultsSyngeneic tracheal grafts from different transplant sites retained normal histologic structures, while their corresponding allografts demonstrated more occlusion of the airway lumen as well as more infiltration of CD4+/CD8+ mononuclear cells and myofibroblasts, but less regenerative epithelium and neovascularized vessels at indicated times (P<0.05). Compared with two heterotopic allografts, orthotopic allografts had less occlusion of the tracheal lumen as well as less infiltration of CD4+/CD8+ mononuclear cells and myofibroblasts, but more regenerative epithelium and neovascularized vessels (P<0.05).ConclusionsOrthotopic tracheal transplantation in mice can be considered as a model to study early stages of obliterative bronchiolitis, and heterotopic tracheal transplantation can be a model for late stages of obliterative bronchiolitis

Study on the influencing factors and strategies of sorted collection of urban refuse in China

Although the sorted collection of urban refuse in China started later than that in developed countries, it has been sustained 14 years since the implementation of pilot project of waste sorting. However, the waste sorting among cities is still making slow progress and beset with difficulties in China. With a review of the actual situation of waste sorting in China, this article firstly introduced the urban refuse sorted way in China, and then analysed the influencing factors of the sorted collection of urban refuse. At last, we put forward some strategies and suggestions for dealing with the prominent challenges of the sorted collection of urban refuse in China

Visualizing the elongated vortices in γ\gamma-Ga nanostrips

We study the magnetic response of superconducting $\gamma$-Ga via low temperature scanning tunneling microscopy and spectroscopy. The magnetic vortex cores rely substantially on the Ga geometry, and exhibit an unexpectedly-large axial elongation with aspect ratio up to 40 in rectangular Ga nano-strips (width $l$ $<$ 100 nm). This is in stark contrast with the isotropic circular vortex core in a larger round-shaped Ga island. We suggest that the unusual elongated vortices in Ga nanostrips originate from geometric confinement effect probably via the strong repulsive interaction between the vortices and Meissner screening currents at the sample edge. Our finding provides novel conceptual insights into the geometrical confinement effect on magnetic vortices and forms the basis for the technological applications of superconductors.Comment: published in Phys. Rev. B as a Rapid Communicatio

A Hybrid Artificial Bee Colony Algorithm for Flexible Job Shop Scheduling Problems

In this paper, we propose a hybrid Pareto-based artificial bee colony (HABC) algorithm for solving the multi-objective flexible job shop scheduling problem. In the hybrid algorithm, each food sources is represented by two vectors, i.e., the machine assignment vector and the operation scheduling vector. The artificial bee is divided into three groups, namely, employed bees, onlookers, and scouts bees. Furthermore, an external Pareto archive set is introduced to record non-dominated solutions found so far. To balance the exploration and exploitation capability of the algorithm, the scout bees in the hybrid algorithm are divided into two parts. The scout bees in one part perform randomly search in the predefined region while each scout bee in another part randomly select one non-dominated solution from the Pareto archive set. Experimental results on the well-known benchmark instances and comparisons with other recently published algorithms show the efficiency and effectiveness of the proposed algorithm

Bis(4′-hy­droxy­biphenyl-4-carboxyl­ato-κO 1)(1,10-phenanthroline-κ2 N,N′)zinc

In the title compound, [Zn(C13H9O3)2(C12H8N2)], the ZnII atom is located on a twofold rotation axis and has a distorted tetra­hedral coordination with two N atoms from the phenanthroline ligand arranged around the twofold axis and two O atoms from two symmetry-related 4′-hy­droxy­biphenyl-4-carboxyl­ate ligands. The mol­ecules are linked by O—H⋯O hydrogen bonds, forming a chain developing parallel to [101]

Poly[[{μ3-dihydrogen [(pyridin-4-yl­methyl­imino)­bis­(methyl­ene)]diphos­phon­ato-κ5 O:O′,N,O′′:N′}copper(II)] dihydrate]

In the title polymer, {[Cu(C8H12N2O6P2)]·2H2O}n, the geometry of the five-coordinate CuII ion can best be described as slightly distorted square-pyramidal formed by one N and two O atoms of an N(CH2PO3H)2 group and one N atom from a pyridine ring. The elongated apex of the pyramid is occupied by one O atom from a third diphospho­nate ligand. The inter­connection of Cu2+ ions by the diphospho­nate ligands results in the formation of a double-chain array along the b axis, in which the two sub-chains are inter­locked by pairs of PO3 groups. The outside of each sub-chain is decorated by other PO3 groups. These double chains are further assembled into a three-dimensional supra­molecular architecture via a large number of O—H⋯O hydrogen bonds between the phospho­nate groups and lattice water mol­ecules