15,564 research outputs found

    Three-loop HTLpt thermodynamics at finite temperature and chemical potential

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    In this proceedings we present a state-of-the-art method of calculating thermodynamic potential at finite temperature and finite chemical potential, using Hard Thermal Loop perturbation theory (HTLpt) up to next-to-next-leading-order (NNLO). The resulting thermodynamic potential enables us to evaluate different thermodynamic quantities including pressure and various quark number susceptibilities (QNS). Comparison between our analytic results for those thermodynamic quantities with the available lattice data shows a good agreement.Comment: 5 pages, 6 figures, conference proceedings of XXI DAE-BRNS HEP Symposium, IIT Guwahati, December 2014; to appear in 'Springer Proceedings in Physics Series

    Computationally efficient quantum-mechanical technique to calculate direct tunnelling gate leakage current in metal-oxide-semiconductor structures

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    We propose a computationally efficient, accurate and numerically stable quantum- mechanical technique to calculate the direct tunneling (DT)gate current in metal-oxide-semiconductor (MOS) structures. Knowledge of the imaginary part G of the complex eigenenergy of the quasi-bound inversion layer states is required to estimate the lifetimes of these states. Exploiting the numerically obtained exponential dependence of G on the thickness of the gate-dielectric layer even in the sub-1-nm-thickness regime, we have simplified the determination of G in devices where it is too small to be calculated directly. It is also shown that the MOS electrostatics, calculated self-consistently with open boundary conditions, is independent of the dielectric layer tickness provided that the other parameters remain unchanged. Utilizing these findings, a computationally efficient and numerically stable method is developed for calculating the tunneling current–gate voltage characteristics. The validity of the proposed model is demonstrated by comparing simulation results with experimental data. Sample calculations for MOS transistors with high-K gate-dielectric materials are also presented. This model is particularly suitable for DT current calculation in devices with thicker gate dielectrics and in device or process characterization from the tunneling current measurement

    Microscale application of column theory for high resolution force and displacement sensing

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    We present the design, fabrication and experimental validation of a novel device that exploits the amplification of displacement and attenuation of structural stiffness in the post-buckling deformation of slender columns to obtain pico-Newton force and nanometer displacement resolution even under an optical microscope. The extremely small size, purely mechanical sensing scheme and vacuum compatibility of the instrument makes it compatible with existing visualization tools of nanotechnology. The instrument has a wide variety of potential applications ranging from electro-mechanical characterization of one dimensional solids to single biological cells

    Accurate modeling of gate capacitance in deep submicron MOSFETs with high-K gate-dielectrics

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    Gate capacitance of metal-oxide-semiconductor devices with ultra-thin high-K gate-dielectric materials is calculated taking into account the penetration of wave functions into the gate-dielectric. When penetration effects are neglected, the gate capacitance is independent of the dielectric material for a given equivalent oxide thickness (EOT). Our selfconsistent numerical results show that in the presence of wave function penetration, even for the same EOT, gate capacitance depends on the gate-dielectric material. Calculated gate capacitance is higher for materials with lower conduction band offsets with silicon. We have investigated the effects of substrate doping density on the relative error in gate capacitance due to neglecting wave function penetration. It is found that the error decreases with increasing doping density. We also show that accurate calculation of the gate capacitance including wave function penetration is not critically dependent on the value of the electron effective mass in the gate-dielectric region

    The prevalence of occult hepatitis B virus (hbv) infection in a large multi-ethnic haemodialysis cohort.

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    Haemodialysis patients are at increased risk of exposure to blood borne viruses. To reduce transmission in the UK, all haemodialysis patients are regularly screened, and if susceptible to Hepatitis B virus (HBV) infection, vaccinated

    Lubrication of DLC Coatings with Two Tris(pentafluoroethyl)trifluorophosphate Anion-Based Ionic Liquids

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    The lubrication of a Cr-DLC coating with ethyl-dimethyl-2-methoxyethylammonium tris(pentafluoroethyl)trifluoropho-sphate [(NEMM)MOE][FAP] and 1-butyl-1-methylpyrro-lidinium tris(pentafluoroethyl)trifluorophosphate [BMP] [FAP] ionic liquids (ILs) as 1 wt% additives to a polyalphaolefin (PAO 6) was studied. Zinc dialkyldithiophosphate (ZDDP) was also used as reference in order to evaluate the effectiveness of the ILs. Reciprocating ball-on-plate tribological tests at loads of 20 and 40 N were performed. The results showed that both ILs exhibited a friction reduction, especially at the lowest load tested. Antiwear properties were also improved; the PAO 6 + 1% [BMP][FAP] mixture was slightly better, close to the values for PAO 6 + 1% ZDDP. Scanning electron microscopy (SEM) images and X-ray photoelectron spectroscopy (XPS) analysis indicated that the additive–surface interaction was responsible for the tribological improvement

    Segmentation of Nastaliq script for OCR

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    In this paper we have presented a novel segmentation technique for the implementation of an OCR (Optical Character Recognition) for printed Nastalique text, a calligraphic style of Urdu which uses the Arabic script for its writing.OCR for many of the world major languages have been developed and are being used but at present an OCR for Nastalique is not available and the published research on Nastalique OCR, Urdu OCR or even on any area of Urdu computing is almost non-existent, the reason being the challenges that the Nastalique style poses for its optical recognition. We used Matlab 7 for our experimentation the results are reported in this paper which are very encouraging
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