9,606 research outputs found

    Strain-mediated metal-insulator transition in epitaxial ultra-thin films of NdNiO3

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    We have synthesized epitaxial NdNiO3_{3} ultra-thin films in a layer-by-layer growth mode under tensile and compressive strain on SrTiO3_{3} (001) and LaAlO3_3 (001), respectively. A combination of X-ray diffraction, temperature dependent resistivity, and soft X-ray absorption spectroscopy has been applied to elucidate electronic and structural properties of the samples. In contrast to the bulk NdNiO3_{3}, the metal-insulator transition under compressive strain is found to be completely quenched, while the transition remains under the tensile strain albeit modified from the bulk behavior.Comment: 4 pages, 4 figure

    The trends and dependencies between air and water temperatures in lakes in northern Poland in 1961?2000

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    International audienceOver 40 years, from 1961?2000, daily mean values of surface lake water temperatures at 0.4 m depth in six lakes in northern Poland were recorded with nearby mean daily air temperatures at 2 m. Air temperatures increased on average from 0.020 to 0.025°C year?1 while lake-water temperatures varied more but increased by 0.005 to 0.028°C year-1. For shorter periods (for instance, for 10 days) the pattern of trend directions and values was more complex, depending on the morphometric and trophic conditions of the lakes. It has been concluded that changes in lake water temperatures during climate warming may be documented by studies of lakes located relatively closely together (up to 300 kilometres). Keywords: physical limnology, climate changes, lake water, temperatur

    Spin polarized neutron matter within the Dirac-Brueckner-Hartree-Fock approach

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    The relation between energy and density (known as the nuclear equation of state) plays a major role in a variety of nuclear and astrophysical systems. Spin and isospin asymmetries can have a dramatic impact on the equation of state and possibly alter its stability conditions. An example is the possible manifestation of ferromagnetic instabilities, which would indicate the existence, at a certain density, of a spin-polarized state with lower energy than the unpolarized one. This issue is being discussed extensively in the literature and the conclusions are presently very model dependent. We will report and discuss our recent progress in the study of spin-polarized neutron matter. The approach we take is microscopic and relativistic. The calculated neutron matter properties are derived from realistic nucleon-nucleon interactions. This makes it possible to understand the nature of the EOS properties in terms of specific features of the nuclear force model.Comment: 6 pages, 11 figures, revised/extended calculation

    h-deformation of GL(1|1)

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    h-deformation of (graded) Hopf algebra of functions on supergroup GL(1|1) is introduced via a contration of GL_q (1|1). The deformation parameter h is odd (grassmann). Related differential calculus on h-superplane is presented.Comment: latex file, 8 pages, minor change

    An integrated DC-DC step-up charge pump and step-down converter in 130 nm technology

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    After the LHC luminosity upgrade the number of readout channels in the ATLAS Inner Detector will be increased by one order of magnitude and delivering the power to the front-end electronics as well as cooling will become a critical system issue. Therefore a new solution for powering the readout electronics has to be worked out. Two main approaches for the power distribution are under development, the serial powering of a chain of modules and the parallel powering with a DCDC conversion stage on the detector. In both cases switchedcapacitor converters in the CMOS front-end chips will be used. In the paper we present the design study of a step-up charge pump and a step-down converter. In optimized designs power efficiency of 85 % for the step-up converter and 92 % for the step-down converter has been achieved
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