Quantum oscillations and a non-trivial Berry phase in the noncentrosymmetric superconductor BiPd

We report the measurements of de Haas-van Alphen (dHvA) oscillations in the noncentrosymmetric superconductor BiPd. Several pieces of a complex multi-sheet Fermi surface are identified, including a small pocket (frequency 40 T) which is three dimensional and anisotropic. From the temperature dependence of the amplitude of the oscillations, the cyclotron effective mass is ($0.18$ $\pm$ 0.1) $m_e$. Further analysis showed a non-trivial $\pi$-Berry phase is associated with the 40 T pocket, which strongly supports the presence of topological states in bulk BiPd and may result in topological superconductivity due to the proximity coupling to other bands.Comment: 5 pages, 3 figure

Parametric Analysis of a Coupled Photovoltaic/Thermal Concentrating Solar Collector for Electricity Generation

The analysis of the combined efficiencies in a coupled photovoltaic (PV)/thermal concentrating solar collector are presented based on a coupled electrical/thermal model. The calculations take into account the drop in efficiency that accompanies the operation of PV cells at elevated temperatures along with a detailed analysis of the thermal system including losses. An iterative numerical scheme is described that involves a coupled electrothermal simulation of the solar energy conversion process. In the proposed configuration losses in the PV cell due to reduced efficiencies at elevated temperatures and the incident solar energy below the PV bandgap are both harnessed as heat. This thermal energy is then used to drive a thermodynamic power cycle. The simulations show that it is possible to optimize the overall efficiency of the system by variation in key factors such as the solar concentration factor, the band gap of the PV material, and the system thermal design configuration, leading to a maximum combined efficiency of similar to 32.3% for solar concentrations between 10-50 and a band-gap around 1.5-2.0 eV. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3514590

Impact of Analog and Digital Pre-emphasis on the Signal-to-Noise Ratio of Bandwidth-limited Optical Transceivers

The ever-growing machine-to-machine traffic in data centers has stimulated the increase of transceiver data rate from 25Gb/s/λ to 100Gb/s/λ and beyond. It is believed that advanced modulation formats and digital-to-analog converters (DACs) will be employed in next generation short-reach transceivers. Digital pre-emphasis techniques are widely employed in DAC-based transceivers to compensate for the high frequency roll-off due to the RF and optoelectronics components in optical transceivers. However, digital pre-emphasis essentially reduces the magnitude of the signal low frequency components for a flat frequency response, which unavoidably increases quantization error, reducing the overall signal-to-noise ratio. This trade-off between SNR and bandwidth conflicts with the high SNR requirement of advanced modulation formats such as the Nyquist-shaped pulse amplitude modulation (PAM). To mitigate the quantization error induced SNR degradation, we show that analog pre-emphasis filters can be used in conjunction with digital pre-emphasis for improved system performance. To understand the impact of the analog pre-emphasis filter on system performance, we analyze the relationship between the flatness of the system frequency response and the SNR degradation due to digital pre-emphasis, and demonstrate 1.1-dB increase of receiver sensitivities, for both 64-Gb/s and 128-Gb/s intensity-modulation direct detection (IM-DD) 20 PAM4 signals, respectively employing a directly modulated laser (DML) and an electroabsorption modulator (EAM)

You’re the emotional one: the role of perspective for emotion processing in reading comprehension

Two experiments were conducted to explore whether perspective influences the way readers engage with and process emotional information while reading. Texts presenting characters in an emotional situation from either a personal or an onlooker perspective were presented and reading times were measured for each sentence. Participants also provided emotional self-ratings after reading. In the first experiment, positive texts were processed with greater ease, especially when readers experienced the texts from a personal perspective. In Experiment 2, an emotional match/mismatch was inserted so that a final explicit emotion word either matched or mismatched the emotional valence of the text. Mismatch effects were stronger and more consistent for the personal perspective. The two experiments provide evidence that the perspective of the reader can influence emotion processing. Processing of emotional information was easier for the personal perspective, and readers were more sensitive to inconsistent emotional information from that perspective

High-intensity drying processes: Impulse drying. Progress report on furnish evaluations for impulse drying commercialization demonstration

Laboratory and pilot scale experiments were performed to identify potential furnishes and operating parameters for upcoming high-speed pilot scale trials and commercial demonstration of impulse drying of heavy weight grades of paper. Results indicate that hydrodynamic specific surface is highly dependent on sheet formation and prehandling. Mill refined pulp and machine paper were comparable to laboratory prepared samples in regards to permeability and impulse drying. Process variables such as platen surface coating, felt type, felt moisture, and presteaming temperature profiles were investigated. Substantial improvements in sheet smoothness were achieved

Characterization of the second- and third-order nonlinear optical susceptibilities of monolayer MoS2_2 using multiphoton microscopy

We report second- and third-harmonic generation in monolayer MoS$_\mathrm{2}$ as a tool for imaging and accurately characterizing the material's nonlinear optical properties under 1560 nm excitation. Using a surface nonlinear optics treatment, we derive expressions relating experimental measurements to second- and third-order nonlinear sheet susceptibility magnitudes, obtaining values of $|\chi_s^{(2)}|=2.0\times10^{-20}$ m$^2$ V$^{-1}$ and for the first time for monolayer MoS$_\mathrm{2}$, $|\chi_s^{(3)}|=1.7\times10^{-28}$ m$^3$ V$^{-2}$. These sheet susceptibilities correspond to effective bulk nonlinear susceptibility values of $|\chi_{b}^{(2)}|=2.9\times10^{-11}$ m V$^{-1}$ and $|\chi_{b}^{(3)}|=2.4\times10^{-19}$ m$^2$ V$^{-2}$, accounting for the sheet thickness. Experimental comparisons between MoS$_\mathrm{2}$ and graphene are also performed, demonstrating $\sim$3.4 times stronger third-order sheet nonlinearity in monolayer MoS$_\mathrm{2}$, highlighting the material's potential for nonlinear photonics in the telecommunications C band.Comment: Accepted by 2D Materials, 28th Oct 201

The shape of equality: discourses around the Section 28 repeal in Scotland

This article focuses on conceptualizations of equality in the discourses deployed in the campaign to repeal Section 28 in Scotland. I use the parliamentary debates and two newspapers: the Daily Record, which supported the campaign to Keep the Clause, and The Guardian, which supported repeal, to exemplify the different discursive articulations around equality and citizenship. I suggest that the Scottish example provides further evidence of the ways in which liberalism naturalizes heterosexuality as the standard for citizenship and thus bequeaths a hierarchy of 'equality' and citizenship in the realm of sexuality, wherein lesbian and gay citizenship is either rendered invalid or characterized as 'special rights'. However, within the narrow confines of the parliamentary debates, more expansive and differentiated notions of citizenship and equality are evident. Whilst I conclude that the 'shape' of equality achieved through the repeal has been moulded to support institutionalized heterosexuality - with Section 28 replaced by statutory guidelines on sex education which advocate marriage - I also suggest equality is contested, both through the recognition of transformations in heterosexual family forms and the appeal to non-discrimination as a democratic principle. It is possible, therefore, that current destabilizations of the heterosexual social order simultaneously destabilize the precepts of liberal democracy