46 research outputs found

    Why all the fuss about 2D semiconductors?

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    Graphene is no longer alone; a family of atomically thin 2D semiconductors has emerged. Optoelectronics and photonics applications are in their experimental infancy but the future holds much promise.Comment: Commentary article, 1 figure, 1 tabl

    First High-Convergence Cryogenic Implosion in a Near-Vacuum Hohlraum

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    Recent experiments on the National Ignition Facility [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] demonstrate that utilizing a near-vacuum hohlraum (low pressure gas-filled) is a viable option for high convergence cryogenic deuterium-tritium (DT) layered capsule implosions. This is made possible by using a dense ablator (high-density carbon), which shortens the drive duration needed to achieve high convergence: a measured 40% higher hohlraum efficiency than typical gas-filled hohlraums, which requires less laser energy going into the hohlraum, and an observed better symmetry control than anticipated by standard hydrodynamics simulations. The first series of near-vacuum hohlraum experiments culminated in a 6.8 ns, 1.2 MJ laser pulse driving a 2-shock, high adiabat (α ~ 3.5) cryogenic DT layered high density carbon capsule. This resulted in one of the best performances so far on the NIF relative to laser energy, with a measured primary neutron yield of 1.8×10[superscript 15] neutrons, with 20% calculated alpha heating at convergence ~27×

    Mission impossible? Assessing the veracity of a mental health problem as result of a road traffic accident: a preliminary review of UK experts’ practices

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    The number of people claiming for personal injury after being involved in a road traffic accident (RTA) in the UK continues to soar. In April 2015, the UK Government intervened to implement measures aimed at reducing the prevalence of fraud within such personal injury claims. However, these reforms did not include claims for mental disorder that arise because of a RTA despite being responsible for substantially larger payouts in comparison with claims for whiplash. The present study examines the assessment practice for detecting fraudulent claims of this nature using a mixed methods survey analysing UK medico-legal professionals’ assessment methodologies (N = 37). The findings suggest comprehensively that assessment practices in this field are idiosyncratic. The findings evidence limitations in all aspects of the assessment process from medico-legal assessors being asked to undertake examinations without the presence of medical records to 44% of examiners being unaware of the three types of malingering. The article concludes with recommendations for improving both assessments and the assessment process for assessing RTA claimants in the UK

    Salmeterol/fluticasone stable-dose treatment compared with formoterol/budesonide adjustable maintenance dosing: impact on health-related quality of life-0

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    <p><b>Copyright information:</b></p><p>Taken from "Salmeterol/fluticasone stable-dose treatment compared with formoterol/budesonide adjustable maintenance dosing: impact on health-related quality of life"</p><p>Respiratory Research 2007;8(1):46-46.</p><p>Published online 4 Jul 2007</p><p>PMCID:PMC1924504.</p><p></p

    Direct observation of ultraslow hyperbolic polariton propagation with negative phase velocity

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    Polaritons with hyperbolic dispersion are key to many emerging photonic technologies, including subdiffraction imaging, sensing and spontaneous emission engineering1, 2, 3, 4, 5, 6, 7, 8. Fundamental to their effective application are the lifetimes of the polaritons, as well as their phase and group velocities7, 9. Here, we combine time-domain interferometry10 and scattering-type near-field microscopy11 to visualize the propagation of hyperbolic polaritons in space and time, allowing the first direct measurement of all these quantities. In particular, we study infrared phonon polaritons in a thin hexagonal boron nitride8, 12, 13 waveguide exhibiting hyperbolic dispersion and deep subwavelength-scale field confinement. Our results reveal—in a natural material—negative phase velocity paired with a remarkably slow group velocity of 0.002c and lifetimes in the picosecond range. While these findings show the polariton's potential for mediating strong light–matter interactions and negative refraction, our imaging technique paves the way to explicit nanoimaging of polariton propagation characteristics in other two-dimensional materials, metamaterials and waveguides.Peer Reviewe
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