1,305 research outputs found

    Structural origins of electronic conduction in amorphous copper-doped alumina

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    We perform an {\it ab initio} modeling of amorphous copper-doped alumina (a-Al2_2O3_3:Cu), a prospective memory material based on resistance switching, and study the structural origin of electronic conduction in this material. We generate molecular dynamics based models of a-Al2_2O3_3:Cu at various Cu-concentrations and study the structural, electronic and vibrational properties as a function of Cu-concentration. Cu atoms show a strong tendency to cluster in the alumina host, and metallize the system by filling the band gap uniformly for higher Cu-concentrations. We also study thermal fluctuations of the HOMO-LUMO energy splitting and observe the time evolution of the size of the band gap, which can be expected to have an important impact on the conductivity. We perform a numerical computation of conduction pathways, and show its explicit dependence on Cu connectivity in the host. We present an analysis of ion dynamics and structural aspects of localization of classical normal modes in our models

    Do more with less: managing public investment in federal Nepal

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    Nepal's success or failure hinges on how effectively the governments at all levels can deliver public services, which demands proper fiscal and investment management. Mukti Subedi and Bishal K Chalise write that the national framework for public financial management, particularly in the context of transition to federalism, is non-existent

    Precise Pressure Dependence of the Superconducting Transition Temperature of FeSe: Resistivity and ^77Se--NMR Study

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    We report the precise pressure dependence of FeSe from a resistivity measurement up to 4.15 GPa. Superconducting transition temperature (T_c) increases sensitively under pressure, but shows a plateau between 0.5-1.5 GPa. The maximum T_c, which is determined by zero resistance, is 21 K at approximately 3.5 GPa. The onset value reaches ~37 K at 4.15 GPa. We also measure the nuclear spin-lattice relaxation rate 1/T_1 under pressure using 77Se--NMR measurement. 1/T_1 shows that bulk superconductivity is realized in the zero-resistance state. The pressure dependence of 1/T_1T just above T_c shows a plateau as well as the pressure dependence of T_c, which gives clear evidence of the close relationship between 1/T_1T and T_c. Spin fluctuations are suggested to contribute to the mechanism of superconductivity.Comment: 4pages, 6figures: to be published in J. Phys. Soc. Jpn. Vol.78 No.6 (2009

    Economic Analysis of Fish Production Using Different Feed Types Practiced in Dhanusha District, Nepal

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    A study on the economic analysis of fish production using different feed types practiced in Dhanusha district was conducted in 2018. Out of 600 fish farmers, sixty fish farmers(10%) from the Fish Superzone region i.e. Janakpur sub-metropolitan city, Bideh municipality, Sahidnagar municipality, Kamala municipality, Hanspur municipality, Janaknandani rural municipality and Aaurahi  rural municipality, selected using simple random sampling, were surveyed using semi-structured questionnaire. The study revealed that locally formulated mash feed was commonly used feed type in which rice bran and mustard oil cake (RB+MOC) was the principle feed ingredient. 55% of the farmers used rice bran and mustard oil cake (RB+MOC), 20% used rice bran, mustard oil cake and soybean (RB+MOC+SOB), 10% used rice bran, mustard oil cake and fish meal (RB+MOC+FM) and 15% farmers mineral and vitamin (RB+MOC+MIN/VIT) in their feed formulation. The productivity of the fish production in feed type RB+MOC+SOB (3.41±1.02) was significantly higher than other feed type.  The total variable cost per ha (5.23±2.11) was found significantly(p<0.05) higher in feed type RB+MOC+SOB. Similarly, gross margin (4.44±2.74) received by farmers of feed type RB+MOC+SOB was also significantly high(p<0.05). The Benefit: Cost (B:C) ratio of the study area was found to be 1.69, high being of feed type RB+MOC+SOB(1.84) compared to others. The feed type RB+MOC+SOB is seen as a economically profitable one in the study area because of the high productivity, profit and B:C ratio. High feed cost was the major problem followed by the unavailability of feed. Fish farming can be a profitable business in Dhanusha with large opportunity to increase the fish production with increasing protein sources in the feed used. Farmers should be provided sufficient information, trainings and be encouraged to incorporate the protein rich sources like soybean and fish meal in the feed prepared to increase the productivity and ultimately return

    Novel multiple-band superconductor SrPt2As2

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    We present LDA calculated electronic structure of recently discovered superconductor SrPt2As2 with Tc=5.2K. Despite its chemical composition and crystal structure are somehow similar to FeAs-based high-temperature superconductors, the electronic structure of SrPt2As2 is very much different. Crystal structure is orthorhombic (or tetragonal if idealized) and has layered nature with alternating PtAs4 and AsPt4 tetrahedra slabs sandwiched with Sr ions. The Fermi level is crossed by Pt-5d states with rather strong admixture of As-4p states. Fermi surface of SrPt2As2 is essentially three dimensional, with complicated sheets corresponding to multiple bands. We compare SrPt2As2 with 1111 and 122 representatives of FeAs-class of superconductors, as well as with isovalent (Ba,Sr)Ni2As2 superconductors. Brief discussion of superconductivity in SrPt2As2 is also presented.Comment: 5 pages, 4 figure

    Magnetic Properties of Ab initio Model for Iron-Based Superconductors LaFeAsO

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    By using variational Monte Carlo method, we examine an effective low-energy model for LaFeAsO derived from an ab initio downfolding scheme. We show that quantum and many-body fluctuations near a quantum critical point largely reduce the antiferromagnetic (AF) ordered moment and the model not only quantitatively reproduces the small ordered moment in LaFeAsO, but also explains the diverse dependence on LaFePO, BaFe2As2 and FeTe. We also find that LaFeAsO is under large orbital fluctuations, sandwiched by the AF Mott insulator and weakly correlated metals. The orbital fluctuations and Dirac-cone dispersion hold keys for the diverse magnetic properties.Comment: 4 pages, 4 figure

    Aid conditionalities, international Good Manufacturing Practice standards and local production rights: a case study of local production in Nepal

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    © 2015 Brhlikova et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.This work was supported by the Economic and Social Research Council and the Department for International Development [RES-167-25-0110] through the collaborative research project Tracing Pharmaceuticals in South Asia (2006 – 2009). In addition to the authors of this paper, the project team included: Soumita Basu, Gitanjali Priti Bhatia, Erin Court, Abhijit Das, Stefan Ecks, Patricia Jeffery, Roger Jeffery, Rachel Manners, and Liz Richardson. Martin Chautari (Kathmandu) and the Centre for Health and Social Justice (New Delhi) provided resources drawn upon in writing this paper but are not responsible for the views expressed, nor are ESRC or DFID. Ethical review was provided by the School of Social and Political Science at the University of Edinburgh, and ethical approval in Nepal for the study granted by the Nepal Health Research Council (NHRC)
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