Generalized laws of reflection and refraction from transformation optics

Based on transformation optics, we introduce another set of generalized laws of reflection and refraction (differs from that of [Science 334, 333 (2011)]), through which a transformation media slab is derived as a meta-surface, producing anomalous reflection and refraction for all polarizations of incident light.Comment: 7 pages, 3 figure

Estimation of Extreme Quantiles for Functions of Dependent Random Variables

We propose a new method for estimating the extreme quantiles for a function of several dependent random variables. In contrast to the conventional approach based on extreme value theory, we do not impose the condition that the tail of the underlying distribution admits an approximate parametric form, and, furthermore, our estimation makes use of the full observed data. The proposed method is semiparametric as no parametric forms are assumed on all the marginal distributions. But we select appropriate bivariate copulas to model the joint dependence structure by taking the advantage of the recent development in constructing large dimensional vine copulas. Consequently a sample quantile resulted from a large bootstrap sample drawn from the fitted joint distribution is taken as the estimator for the extreme quantile. This estimator is proved to be consistent. The reliable and robust performance of the proposed method is further illustrated by simulation.Comment: 18 pages, 2 figure

Research on the Train-Bridge Coupled Vibration and Dynamic Performance of Steel Box Hybrid Girder Cable-Stayed Railway Bridge

Based on the Yongjiang Bridge, this paper used the numerical calculation and the field dynamic load test to study the coupled vibration and dynamic response of the steel box hybrid girder cable-stayed railway bridge. Each vehicle in the train was simulated with 31 degrees of freedom, and the oscillatory differential equation of vehicle-bridge coupling was established by MATLAB software. Afterwards, the field tests were also conducted to determine the free vibration characteristics as well as the strain, displacement, and acceleration of the bridge superstructure under trains moving at different speeds and braking at a specified position from a set speed. According to the dynamic load test and Vehicle-Bridge Coupling Vibration analysis, the following conclusions are obtained: (1) The calculated results of vehicle-bridge coupling vibration agreed well with the measured ones, and the program could be used to analyze the dynamic performance of Railway cable-stayed bridges with steel box composite girders. (2) The measured first-order natural frequencies of transverse, vertical and longitudinal vibration were 0,39 Hz; 0,49 Hz and 0,88 Hz, respectively. The dynamic coefficients are 1,04 – 1,13, the maximum lateral and vertical accelerations are 1,10 m/s2 and 1,11 m/s2, and the maximum derailment coefficient and load reduction rate are 0,55 and 0,39, respectively. These data showed that the dynamic parameters of bridges and vehicles met the requirements and had good stiffness and dynamic performance. (3) This paper, using the frequency limit of simply supported beam to restrain the natural frequencies of cable-stayed bridges is not appropriate, and it is necessary to propose the natural frequency limit value of cable-stayed bridge

Simulation and Test of Lateral Ballast Resistance to 1435 mm/1000 mm Dual-Gauge Sleepers

The stability of a 1000 mm/1435 mm dual-gauge track is lower than that of a single-gauge track. One of the important factors that affects the stability of the track is the lateral resistance of the track bed. We have established a discrete element simulation model of the dual-gauge sleeper-track bed in PFC to analyse the characteristics of the lateral resistance of the 1000 mm/1435 mm dual-gauge sleeper. With China Type IIIc sleepers as the control group, we carried out the lateral resistance test for the full-scale sleeper model under the same conditions. The research results indicate that the most effective way to increase the lateral resistance of the dual-gauge track bed is to increase the end surface area and bottom area of the sleeper. The application of adjacent sleepers is an effective way to increase the lateral resistance of the track bed further. The research results gained from this study can be used to guide the design of dual-gauge sleepers

Identification, cloning and characterization of sis7 and sis10 sugar-insensitive mutants of Arabidopsis

<p>Abstract</p> <p>Background</p> <p>The levels of soluble sugars, such as glucose and sucrose, help regulate many plant metabolic, physiological and developmental processes. Genetic screens are helping identify some of the loci involved in plant sugar response and reveal extensive cross-talk between sugar and phytohormone response pathways.</p> <p>Results</p> <p>A forward genetic screen was performed to identify mutants with increased resistance to the inhibitory effects of high levels of exogenous sugars on early <it>Arabidopsis </it>seedling development. The positional cloning and characterization of two of these <it>sugar insensitive </it>(<it>sis</it>) mutants, both of which are also involved in abscisic acid (ABA) biosynthesis or response, are reported. Plants carrying mutations in <it>SIS7/NCED3/STO1 </it>or <it>SIS10/ABI3 </it>are resistant to the inhibitory effects of high levels of exogenous Glc and Suc. Quantitative RT-PCR analyses indicate transcriptional upregulation of ABA biosynthesis genes by high concentrations of Glc in wild-type germinating seeds. Gene expression profiling revealed that a significant number of genes that are expressed at lower levels in germinating <it>sis7-1/nced3-4/sto1-4 </it>seeds than in wild-type seeds are implicated in auxin biosynthesis or transport, suggesting cross-talk between ABA and auxin response pathways. The degree of sugar insensitivity of different <it>sis10/abi3 </it>mutant seedlings shows a strong positive correlation with their level of ABA insensitivity during seed germination.</p> <p>Conclusion</p> <p>Mutations in the <it>SIS7/NCED3/STO1 </it>gene, which is primarily required for ABA biosynthesis under drought conditions, confer a sugar-insensitive phenotype, indicating that a constitutive role in ABA biosynthesis is not necessary to confer sugar insensitivity. Findings presented here clearly demonstrate that mutations in <it>ABI3 </it>can confer a sugar-insensitive phenotype and help explain previous, mixed reports on this topic by showing that ABA and sugar insensitivity exhibit a strong positive correlation in different <it>abi3 </it>mutants. Expression profiling revealed a potentially novel regulation of auxin metabolism and transport in an ABA deficient mutant, <it>sis7-1/nced3-4/sto1-4</it>.</p

SIS 8, a putative mitogen‐activated protein kinase kinase kinase, regulates sugar‐resistant seedling development in Arabidopsis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106112/1/tpj12404-sup-0001-FigS1-S2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/106112/2/tpj12404.pd

Dirac-Surface-State Modulated Spin Dynamics in a Ferrimagnetic Insulator at Room Temperature

This work demonstrates dramatically modified spin dynamics of magnetic insulator (MI) by the spin-momentum locked Dirac surface states of the adjacent topological insulator (TI) which can be harnessed for spintronic applications. As the Bi-concentration x is systematically tuned in 5 nm thick (BixSb1-x)2Te3 TI film, the weight of the surface relative to bulk states peaks at x = 0.32 when the chemical potential approaches the Dirac point. At this concentration, the Gilbert damping constant of the precessing magnetization in 10 nm thick Y3Fe5O12 MI film in the MI/TI heterostructures is enhanced by an order of magnitude, the largest among all concentrations. In addition, the MI acquires additional strong magnetic anisotropy that favors the in-plane orientation with similar Bi-concentration dependence. These extraordinary effects of the Dirac surface states distinguish TI from other materials such as heavy metals in modulating spin dynamics of the neighboring magnetic layer