An integrated wind risk warning model for urban rail transport in Shanghai, China

The integrated wind risk warning model for rail transport presented has four elements: Background wind data, a wind field model, a vulnerability model, and a risk model. Background wind data uses observations in this study. Using the wind field model with effective surface roughness lengths, the background wind data are interpolated to a 30-m resolution grid. In the vulnerability model, the aerodynamic characteristics of railway vehicles are analyzed with CFD (Computational Fluid Dynamics) modelling. In the risk model, the maximum value of three aerodynamic forces is used as the criteria to evaluate rail safety and to quantify the risk level under extremely windy weather. The full model is tested for the Shanghai Metro Line 16 using wind conditions during Typhoon Chan-hom. The proposed approach enables quick quantification of real- time safety risk levels during typhoon landfall, providing sophisticated warning information for rail vehicle operation safety

Preparation and Properties of MCT Ceramics for RF and THz Applications

The authors would like to thank the Engineering and Physical Sciences Research Council (EPSRC) of UK for financial support under Grant EP/I014845, and, Fujian Provincial Department of Science and Technology of China for financial support under Grant No. 2013H6020

Coexistence of Itinerant Electrons and Local Moments in Iron-Based Superconductors

In view of the recent experimental facts in the iron-pnictides, we make a proposal that the itinerant electrons and local moments are simultaneously present in such multiband materials. We study a minimal model composed of coupled itinerant electrons and local moments to illustrate how a consistent explanation of the experimental measurements can be obtained in the leading order approximation. In this mean-field approach, the spin-density-wave (SDW) order and superconducting pairing of the itinerant electrons are not directly driven by the Fermi surface nesting, but are mainly induced by their coupling to the local moments. The presence of the local moments as independent degrees of freedom naturally provides strong pairing strength for superconductivity and also explains the normal-state linear-temperature magnetic susceptibility above the SDW transition temperature. We show that this simple model is supported by various anomalous magnetic properties and isotope effect which are in quantitative agreement with experiments.Comment: 7 pages, 4 figures; an expanded versio

Disappearance of integer quantum Hall effect

The disappearance of integer quantum Hall effect (IQHE) at strong disorder and weak magnetic field is studied in a lattice model. A generic sequence by which the IQHE plateaus disappear is revealed: higher IQHE plateaus always vanish earlier than lower ones, and extended levels between those plateaus do not float up in energy but keep merging together after the destruction of plateaus. All of these features remain to be true in the weak-field limit as shown by the thermodynamic-localization-length calculation. Topological characterization in terms of Chern integers provides a simple physical explanation and suggests a qualitative difference between the lattice and continuum models.Comment: Revtex, four pages; four figures, postscript fil

New strategies for developing cardiovascular stent surfaces with novel functions (Review)

published_or_final_versio

Lenalidomide regulates CNS autoimmunity by promoting M2 macrophages polarization

Multiple sclerosis (MS) is a chronic and debilitating neurological disorder of the central nervous system (CNS), characterized by infiltration of leukocytes into CNS and subsequent demyelination. Emerging evidences have revealed the beneficial roles of M2 macrophages in ameliorating experimental autoimmune encephalomyelitis (EAE), a model for MS. Here, we identify that lenalidomide alone could promote macrophages M2 polarization to prevent the progression of EAE, which is associated with subsequent inhibition of proinflammatory Th1 and Th17 cells both in peripheral lymph system and CNS. Depletion of macrophages by pharmacology treatment of clodronate liposomes or transferring lenalidomide-induced BMDMs in EAE mice completely abolished the therapeutic effect of lenalidomide or prevented EAE development, respectively. The macrophages-derived IL10 was upregulated both in vivo and in vitro after lenalidomide treatment. Moreover, lenalidomide-treated IL10-dificient EAE mice had higher clinical scores and more severe CNS damage, and intravenous injection of lenalidomide-treated IL10BMDMs into mice with EAE at disease onset did not reverse disease severity, implying IL10 may be essential in lenalidomide-ameliorated EAE. Mechanistically, lenalidomide significantly increased expression and autocrine secretion of IL10, subsequently activated STAT3-mediated expression of Ym1. These studies facilitate the development of potential novel therapeutic application of lenalidomide for the treatment of MS

Analysis of safety climate effect on individual safety consciousness creation and safety behaviour improvement in shipping operations

Unsafe acts of ship officers have been a direct cause of many maritime accidents. In the maritime industry, much effort has been made to prevent unsafe acts and to improve safe behaviours of ship officers. The positive effect of organizational safety climate on human behaviour has been well documented in the literature. Within this context, this paper aims to pioneer the development of the measurement constructs of safety climate in shipping operations and analyze its impact on safety consciousness and behaviour of ship officers. Using primary data collected from 284 deck officers and captains, an exploratory and confirmatory factor analysis and a structural equation model are used to reveal the relationship among the constructs of safety climate, safety consciousness and safety behaviour. The research results show that (1) safety climate generates a direct positive effect on safety consciousness and behaviour; (2) safety consciousness has a positive effect on safety behaviour; and (3) safety consciousness acts as a mediator between safety climate and safety behaviour. Its managerial implications and practical contributions lie in the provision of useful insights on how ship managers can effectively gain the improved safety behaviours of ship officers by appropriate introduction of safety climate and consciousness

Competitions of magnetism and superconductivity in FeAs-based materials

Using the numerical unrestricted Hartree-Fock approach, we study the ground state of a two-orbital model describing newly discovered FeAs-based superconductors. We observe the competition of a $(0, \pi)$ mode spin-density wave and the superconductivity as the doping concentration changes. There might be a small region in the electron-doping side where the magnetism and superconductivity coexist. The superconducting pairing is found to be spin singlet, orbital even, and mixed s$_{xy}$ + d$_{x^{2}-y^{2}}$ wave (even parity).Comment: 5 pages, 3 figure

Reflection Symmetry and Quantized Hall Resistivity near Quantum Hall Transition

We present a direct numerical evidence for reflection symmetry of longitudinal resistivity $\rho_{xx}$ and quantized Hall resistivity $\rho_{xy}$ near the transition between $\nu=1$ quantum Hall state and insulator, in accord with the recent experiments. Our results show that a universal scaling behavior of conductances, $\sigma_{xx}$ and $\sigma_{xy}$, in the transition regime decide the reflection symmetry of $\rho_{xx}$ and quantization of $\rho_{xy}$, independent of particle-hole symmetry. We also find that in insulating phase away from the transition region $\rho_{xy}$ deviates from the quantization and diverges with $\rho_{xx}$.Comment: 3 pages, 4 figures; figure 4 is replace