424 research outputs found

    Electrical Properties of (1–x)La2Mo2O9-xLa2Mo3O12 (x = 0.15) Composite System

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    Electrical properties of (1–x)La2Mo2O9 –xLa2Mo3O12 (x = 0.15) composite system areinvestigated. Introduction of an inert additional phase La2Mo3O12 (adjacent phase to La2Mo2O9 in the phase diagram) results in an increase in conductivity of composite by approximately one order of magnitude. This increase is associated with the appearance of a composite effect. The dominant ionic conductivity is maintained in the wide range of oxygen partial pressures. The calculated ion transport numbers are close to 1. Keywords: lanthanum molybdate, LAMOX, heterogeneous doping, composites, oxide–ion conductivit

    The effect of heterogeneous doping on transport properties of lanthanum dimolybdate

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    A heterogeneous doping method was used for the first time to modify the transport properties of the oxygen-ion conductor La(2)Mo(2)O(9). The effect of temperature and oxygen partial pressure in the gas phase on conductivity of the obtained composite {0.85La2Mo2O9–0.15La2Mo3O12} was studied. Introduction of 15 mol. % an inert low-conductive additional phase La(2)Mo(3)O(12) results in an increase in conductivity of the matrix phase by nearly 1 orders of magnitude. It is associated with appearance of a composite effect. However, there is no suppression of the α-La(2)Mo(2)O(9)↔β-La(2) Mo(2)O(9) phase transition. It is shown that the conductivity type of both lanthanum dimolybdate and composite based on it is predominantly ionic in the wide range of oxygen partial pressures. © Siberian Federal University. All rights reserve

    Interface states in junctions of two semiconductors with intersecting dispersion curves

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    A novel type of shallow interface state in junctions of two semiconductors without band inversion is identified within the envelope function approximation, using the two-band model. It occurs in abrupt junctions when the interband velocity matrix elements of the two semiconductors differ and the bulk dispersion curves intersect. The in-plane dispersion of the interface state is found to be confined to a finite range of momenta centered around the point of intersection. These states turn out to exist also in graded junctions, with essentially the same properties as in the abrupt case.Comment: 1 figur

    PHYSICO-CHEMICAL ATTESTATION OF COMPOSITE SYSTEMS BASED ON ACCEPTOR-DOPED La2Mo2O9 (LAMOX)

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    The aim of work is to enhance ionic conductivity of the La2Mo2O9 by heterogeneous and homogeneous doping. The phases La2Mo2O9 (LM), La2Mo1,5W0,5O9 (LMW), La1,9Ba0,1Mo1,5W0,5O9 (LBMW) and La2Mo1,4Nb0,1W0,5O9 (LMNW) as well ascomposites {(100-y)La2Mo2-xTixO9-δ-yTiO2} (LM-yTi) and {(100-y)La2Mo1,5-xTixW0,5O9-δ-yTiO2} (LMW-yTi)were obtained by solid phase synthesis.Phase composition was checked by Xray diffraction analysis. Electrical properties were examined by impedance spectroscopy.Работа выполнена в рамках государственного задания Минобрнауки РФ

    Tight-binding study of interface states in semiconductor heterojunctions

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    Localized interface states in abrupt semiconductor heterojunctions are studied within a tight-binding model. The intention is to provide a microscopic foundation for the results of similar studies which were based upon the two-band model within the envelope function approximation. In a two-dimensional description, the tight-binding Hamiltonian is constructed such that the Dirac-like bulk spectrum of the two-band model is recovered in the continuum limit. Localized states in heterojunctions are shown to occur under conditions equivalent to those of the two-band model. In particular, shallow interface states are identified in non-inverted junctions with intersecting bulk dispersion curves. As a specific example, the GaSb-AlSb heterojunction is considered. The matching conditions of the envelope function approximation are analyzed within the tight-binding description.Comment: RevTeX, 11 pages, 3 figures, to appear in Phys. Rev.

    TRANSPORT PROPERTIES OF COMPOSITE SYSTEMS {(100-x)La2Mo2O9 – xLa2Mo3O12} WITH DOMINANT OXIDE-ION TRANSFERENCE

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    Electrical properties of composite systems based on LAMOX-family phases were investigated. All phases and composites {(100-x)La2Mo2O9 – xLa2Mo3O12} were obtained by solid phase synthesis. It was established that introduction of 10 or 15 mol. % inert La2Mo3O12 results in an increase in conductivity of composite by 1 orders of magnitude approximately. It is manifestation of composite effect.Работа выполнена в рамках государственного задания Минобрнауки РФ № 4.2288.2017/4.6

    Communicating with providers about racial healthcare disparities: The role of providers’ prior beliefs on their receptivity to different narrative frames

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    Objective Evaluate narratives aimed at motivating providers with different pre-existing beliefs to address racial healthcare disparities. Methods Survey experiment with 280 providers. Providers were classified as high or low in attributing disparities to providers (HPA versus LPA) and were randomly assigned to a non-narrative control or 1 of 2 narratives: “Provider Success” (provider successfully resolved problem involving Black patient) and “Provider Bias” (Black patient experienced racial bias, which remained unresolved). Participants' reactions to narratives (including identification with narrative) and likelihood of participating in disparities-reduction activities were immediately assessed. Four weeks later, participation in those activities was assessed, including self-reported participation in a disparities-reduction training course (primary outcome). Results Participation in training was higher among providers randomized to the Provider Success narrative compared to Provider Bias or Control. LPA participants had higher identification with Provider Success than Provider Bias narratives, whereas among HPA participants, differences in identification between the narratives were not significant. Conclusions Provider Success narratives led to greater participation in training than Provider Bias narratives, although providers’ pre-existing beliefs influenced the narrative they identified with. Practice implications Provider Success narratives may be more effective at motivating providers to address disparities than Provider Bias narratives, though more research is needed

    Prediction of Anisotropic Single-Dirac-Cones in Bi1x{}_{1-x}Sbx{}_{x} Thin Films

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    The electronic band structures of Bi1x{}_{1-x}Sbx{}_{x} thin films can be varied as a function of temperature, pressure, stoichiometry, film thickness and growth orientation. We here show how different anisotropic single-Dirac-cones can be constructed in a Bi1x{}_{1-x}Sbx{}_{x} thin film for different applications or research purposes. For predicting anisotropic single-Dirac-cones, we have developed an iterative-two-dimensional-two-band model to get a consistent inverse-effective-mass-tensor and band-gap, which can be used in a general two-dimensional system that has a non-parabolic dispersion relation as in a Bi1x{}_{1-x}Sbx{}_{x} thin film system

    Pandemic Drugs at Pandemic Speed: Infrastructure for Accelerating COVID-19 Drug Discovery with Hybrid Machine Learning- and Physics-based Simulations on High Performance Computers

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    The race to meet the challenges of the global pandemic has served as a reminder that the existing drug discovery process is expensive, inefficient and slow. There is a major bottleneck screening the vast number of potential small molecules to shortlist lead compounds for antiviral drug development. New opportunities to accelerate drug discovery lie at the interface between machine learning methods, in this case, developed for linear accelerators, and physics-based methods. The two in silico methods, each have their own advantages and limitations which, interestingly, complement each other. Here, we present an innovative infrastructural development that combines both approaches to accelerate drug discovery. The scale of the potential resulting workflow is such that it is dependent on supercomputing to achieve extremely high throughput. We have demonstrated the viability of this workflow for the study of inhibitors for four COVID-19 target proteins and our ability to perform the required large-scale calculations to identify lead antiviral compounds through repurposing on a variety of supercomputers
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