Wide-band SIW cavity-backed circular polarized array antennas with sequential rotation technique

© 2016 IEEE. A circularly-polarized (CP) array antenna based on the substrate integrated waveguide (SIW) technology is proposed. The 2×2 linearly polarized SIW sub-arrays with 90° sequential rotation are employed as the radiating elements on the top layer. The sequential rotation technique is introduced to design SIW corporate-feed network on the bottom layer to realize wideband circular polarized characteristic. The network and the radiating elements of the array are both designed on close SIW structure with low cost printed circuit board (PCB) technology. The simulated results show that, the proposed 4×4 array has a large axial ratio (AR) bandwidth of 14% from 18.3 GHz to 21.1 GHz with a gain above 13 dBi

Multistate latching MEMS variable optical attenuator

Published versio

Smokeless tobacco - a substantial risk for oral potentially malignant disorders in South Asia

Data sources: Medline, the Science Citation Index (SCI) via Web of Science, Scopus, CINAHL, Global Index Medicus, Google Scholar and SLT-related reports of the International Agency for Research on Cancer and the National Cancer Institute of the United States. Study selection: Observational studies on the use of SLT and the risk of developing OPMDs in South Asian Populations. Data extraction and synthesis: Duplicate selection of studies was undertaken with two reviewers undertaking data abstraction and quality assessment independently. Risk and odds ratios were extracted or calculated for studies where possible. Meta odds ratios (mOR) were calculated using a random effects analysis. Results: Fifteen papers reporting 18 studies were included. The majority (12) were from India. All the studies were case-control designs. MOR for any OPMD with the use of any SLT product was 15.5 (95% CI; 9.9–24.2). Risk was higher in women; mOR = 22.2 (95% CI, 9.1–54.1) than men; mOR = 8.7 (95% CI, 2.1–34.8). Betel quid with tobacco carried the highest risk for OPMD, mOR = 16.1 (95% CI, 7.8–33.5). Conclusions: The findings of our study point towards a strong association between some forms of OPMDs and SLT use in South Asia. The risk estimates are high, irrespective of controlling for confounders such as smoking and alcohol or stratification by sex, country or source of controls. There is also an exposure-response relationship between OPMDs and SLT use

Spins in the Vortices of a High Temperature Superconductor

Neutron scattering is used to characterise the magnetism of the vortices for the optimally doped high-temperature superconductor La(2-x)Sr(x)CuO(4) (x=0.163) in an applied magnetic field. As temperature is reduced, low frequency spin fluctuations first disappear with the loss of vortex mobility, but then reappear. We find that the vortex state can be regarded as an inhomogeneous mixture of a superconducting spin fluid and a material containing a nearly ordered antiferromagnet. These experiments show that as for many other properties of cuprate superconductors, the important underlying microscopic forces are magnetic

On the Stability and Structural Dynamics of Metal Nanowires

This article presents a brief review of the nanoscale free-electron model, which provides a continuum description of metal nanostructures. It is argued that surface and quantum-size effects are the two dominant factors in the energetics of metal nanowires, and that much of the phenomenology of nanowire stability and structural dynamics can be understood based on the interplay of these two competing factors. A linear stability analysis reveals that metal nanocylinders with certain magic conductance values G=1, 3, 6, 12, 17, 23, 34, 42, 51, 67, 78, 96, ... times the conductance quantum are exceptionally stable. A nonlinear dynamical simulation of nanowire structural evolution reveals a universal equilibrium shape consisting of a magic cylinder suspended between unduloidal contacts. The lifetimes of these metastable structures are also computed.Comment: 8 pages, 6 figure

Realization of GHZ States and the GHZ Test via Cavity QED

In this article we discuss the realization of atomic GHZ states involving three-level atoms and we show explicitly how to use this state to perform the GHZ test in which it is possible to decide between local realism theories and quantum mechanics. The experimental realizations proposed makes use of the interaction of Rydberg atoms with a cavity prepared in a coherent state.Comment: 16 pages and 3 figures. submitted to J. Mod. Op

Infrared fixed point in quantum Einstein gravity

We performed the renormalization group analysis of the quantum Einstein gravity in the deep infrared regime for different types of extensions of the model. It is shown that an attractive infrared point exists in the broken symmetric phase of the model. It is also shown that due to the Gaussian fixed point the IR critical exponent $\nu$ of the correlation length is 1/2. However, there exists a certain extension of the model which gives finite correlation length in the broken symmetric phase. It typically appears in case of models possessing a first order phase transitions as is demonstrated on the example of the scalar field theory with a Coleman-Weinberg potential.Comment: 9 pages, 7 figures, final version, to appear in JHE

Pareto Optimal Matchings in Many-to-Many Markets with Ties

We consider Pareto-optimal matchings (POMs) in a many-to-many market of applicants and courses where applicants have preferences, which may include ties, over individual courses and lexicographic preferences over sets of courses. Since this is the most general setting examined so far in the literature, our work unifies and generalizes several known results. Specifically, we characterize POMs and introduce the \emph{Generalized Serial Dictatorship Mechanism with Ties (GSDT)} that effectively handles ties via properties of network flows. We show that GSDT can generate all POMs using different priority orderings over the applicants, but it satisfies truthfulness only for certain such orderings. This shortcoming is not specific to our mechanism; we show that any mechanism generating all POMs in our setting is prone to strategic manipulation. This is in contrast to the one-to-one case (with or without ties), for which truthful mechanisms generating all POMs do exist

Effects of boundary conditions on irreversible dynamics

We present a simple one-dimensional Ising-type spin system on which we define a completely asymmetric Markovian single spin-flip dynamics. We study the system at a very low, yet non-zero, temperature and we show that for empty boundary conditions the Gibbs measure is stationary for such dynamics, while introducing in a single site a $+$ condition the stationary measure changes drastically, with macroscopical effects. We achieve this result defining an absolutely convergent series expansion of the stationary measure around the zero temperature system. Interesting combinatorial identities are involved in the proofs

Impurity effects on charge transport and magnetoconductance in a single layer poly(3-hexyl-thiophene) device

received: 2016-01-10 accepted: 2016-05-05 published: 2016-05-17The work was supported by the China Scholarship Council and Engineering (HG, SC, HL, TZ, JH), National Science Foundation of China, 61574095, and Physical Sciences Research Council Grant Nos. EP/J50029X/1, EP/K004484/1, and EP/L020114/1