19,257 research outputs found

    Dielectric relaxation and Charge trapping characteristics study in Germanium based MOS devices with HfO2 /Dy2O3 gate stacks

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    In the present work we investigate the dielectric relaxation effects and charge trapping characteristics of HfO2 /Dy2O3 gate stacks grown on Ge substrates. The MOS devices have been subjected to constant voltage stress (CVS) conditions at accumulation and show relaxation effects in the whole range of applied stress voltages. Applied voltage polarities as well as thickness dependence of the relaxation effects have been investigated. Charge trapping is negligible at low stress fields while at higher fields (>4MV/cm) it becomes significant. In addition, we give experimental evidence that in tandem with the dielectric relaxation effect another mechanism- the so-called Maxwell-Wagner instability- is present and affects the transient current during the application of a CVS pulse. This instability is also found to be field dependent thus resulting in a trapped charge which is negative at low stress fields but changes to positive at higher fields.Comment: 27pages, 10 figures, 3 tables, regular journal contribution (accepted in IEEE TED, Vol.50, issue 10

    Multiplex evaluation of influenza neutralizing antibodies with potential applicability to in-field serological studies

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    The increased number of outbreaks of H5 and H7 LPAI and HPAI viruses in poultry has major public and animal health implications. The continuous rapid evolution of these subtypes and the emergence of new variants influence the ability to undertake effective surveillance. Retroviral pseudotypes bearing influenza haemagglutinin (HA) and neuraminidase (NA) envelope glycoproteins represent a flexible platform for sensitive, readily standardized influenza serological assays. We describe a multiplex assay for the study of neutralizing antibodies that are directed against both influenza H5 and H7 HA. This assay permits the measurement of neutralizing antibody responses against two antigenically distinct HAs in the same serum/plasma sample thus increasing the amount and quality of serological data that can be acquired from valuable sera. Sera obtained from chickens vaccinated with a monovalent H5N2 vaccine, chickens vaccinated with a bivalent H7N1/H5N9 vaccine, or turkeys naturally infected with an H7N3 virus were evaluated in this assay and the results correlated strongly with data obtained by HI assay. We show that pseudotypes are highly stable under basic cold-chain storage conditions and following multiple rounds of freeze-thaw. We propose that this robust assay may have practical utility for in-field sero-surveillance and vaccine studies in resource-limited regions worldwide

    Socio-demographic differences of disability prevalence among the population aged 60 years and over in Bangladesh

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    This study aims to delineate the sociodemographic differences in disability prevalence across the population aged 60 years and over in Bangladesh, and to investigate the association of factors with reporting disability in later life. A microdata sample for those aged 60 years or over from the Census of Bangladesh 2011 was used where disability was assessed with a self-reported single response question. Logistic regression models were performed separately for men and women. Results reveal that the disability prevalence rate increased sharply with age, and it was higher among older women (5.2%) compared to men (4.8%). Physical and vision disabilities were the two categories with the highest prevalence of reported disabilities, with a higher prevalence of physical disability among men and vision disability among women. Being older, female, currently not in marital partnership, and having a lower educational attainment, not being employed, living alone, and residing in the rural areas were significantly associated with reporting disability in later life. The higher prevalence of disability among older women, those who are illiterate, and those residing in rural areas highlights the need for policies prioritising these groups. Special attention should also be given to those who are currently not in marital partnership, particularly women who are living alone

    Who Are Today’s Farmers and What are Their Educational Needs?

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    Labor and Human Capital, Teaching/Communication/Extension/Profession,

    High yield fusion in a Staged Z-pinch

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    We simulate fusion in a Z-pinch; where the load is a xenon-plasma liner imploding onto a deuterium-tritium plasma target and the driver is a 2 MJ, 17 MA, 95 ns risetime pulser. The implosion system is modeled using the dynamic, 2-1/2 D, radiation-MHD code, MACH2. During implosion a shock forms in the Xe liner, transporting current and energy radially inward. After collision with the DT, a secondary shock forms pre-heating the DT to several hundred eV. Adiabatic compression leads subsequently to a fusion burn, as the target is surrounded by a flux-compressed, intense, azimuthal-magnetic field. The intense-magnetic field confines fusion α\alpha-particles, providing an additional source of ion heating that leads to target ignition. The target remains stable up to the time of ignition. Predictions are for a neutron yield of 3.0×10193.0\times 10^{19} and a thermonuclear energy of 84 MJ, that is, 42 times greater than the initial, capacitor-stored energy

    A tight-binding model for MoS2_2 monolayers

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    We propose an accurate tight-binding parametrization for the band structure of MoS2_2 monolayers near the main energy gap. We introduce a generic and straightforward derivation for the band energies equations that could be employed for other monolayer dichalcogenides. A parametrization that includes spin-orbit coupling is also provided. The proposed set of model parameters reproduce both the correct orbital compositions and location of valence and conductance band in comparison with ab initio calculations. The model gives a suitable starting point for realistic large-scale atomistic electronic transport calculations.Comment: 35 pages, 8 figure
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