Search results for "ODS"

Ab initio calculations of CaZrO3 (011) surfaces: systematic trends in polar (011) surface calculations of ABO3 perovskites

2019

Financial support via Latvian-Ukrainian Joint Research Project No. LV-UA/2018/2 for A. I. Popov, Latvian Council of Science Project No. 2018/2-0083 “Theoretical prediction of hybrid nanostructured photocatalytic materials for efficient water splitting” for R. I. Eglitis and J. Kleperis as well as ERAF project No. 1.1.1.1/18/A/073 for R. I. Eglitis and J. Purans is greatly acknowledged.

Electronic and magnetic structure ofLa0.875Sr0.125MnO3calculated by means of hybrid density-functional theory

2007

We present the results of ab initio calculations on magnetic and electronic structures of La1�xSrxMnO3 at low doping, x =1/8. Using the B3LYP hybrid exchange-correlation functional within the framework of densityfunctional theory, we predict a ferromagnetic ground state for La0.875Sr0.125MnO3 in both the low-temperature orthorhombic and the high-temperature pseudocubic phases. This is in contrast to its parent compound LaMnO3, for which we find in agreement with experiment the layered antiferromagnetic state to be the most stable one. The calculated density of states and bond population analysis suggest a tendency of formation of half-metallic spin states in the band gap of both structures.

Ab initio calculations of Nb doped SrTiO3

2010

We present and discuss the results of the large scale Hartree–Fock calculations of Nb impurities substituting for Ti ions in SrTiO3 using ab initio computer code CRYSTAL and several supercells containing up to 135 atoms. The local structure optimisation, the electronic charge redistribution, chemical bond covalence and the band-structure changes induced by the defect are analysed. According to the results of our calculations, Nb is a shallow donor; six nearest O ions are slightly displaced outwards from the Nb ion. The calculated bond population between nearest Ti and O ions (64 me) is much larger than that between Nb and O ions (8 me), since Nb impurity is more ionic than the host Ti.

Time evolution of non-lethal infectious diseases: a semi-continuous approach.

2005

A model describing the dynamics related to the spreading of non-lethal infectious diseases in a fixed-size population is proposed. The model consists of a non-linear delay-differential equation describing the time evolution of the increment in the number of infectious individuals and depends upon a limited number of parameters. Predictions are in good qualitative agreement with data on influenza.

A New Multinomial Accuracy Measure for Polling Bias

2014

In this article, we propose a polling accuracy measure for multi-party elections based on a generalization of Martin, Traugott, and Kennedy's two-party predictive accuracy index. Treating polls as random samples of a voting population, we first estimate an intercept only multinomial logit model to provide proportionate odds measures of each party's share of the vote, and thereby both unweighted and weighted averages of these values as a summary index for poll accuracy. We then propose measures for significance testing, and run a series of simulations to assess possible bias from the resulting folded normal distribution across different sample sizes, finding that bias is small even for polls…

Virtual Reality in Education : Focus on the Role of Emotions and Physiological Reactivity

2019

Cognitive and emotional dimensions are often linked to each other in learning experiences. Moreover, emotions and engagement can lead to better outcomes at the cognitive level. Previous research has indicated that virtual reality (VR) provides a feeling of presence and immersion, which can trigger emotionally engaging learning situations. In this study, we explore the opportunities and challenges related to the use of VR in an educational context. The focus of this article is threefold: First, we explore interdisciplinary research literature related to the use of VR for educational purposes. Second, we introduce our VR pilot study in teacher education, applying three different kinds of VR a…

Edukacja artystyczna źródłem wychowania estetycznego uczniów w młodszym wieku szkolnym

2022

Analiza wpływu podstawników na aromatyczność pierścieni nitrowych i aminowych pochodnych karbazolu

2017

Przedmiotem przeprowadzonych badań była analiza wpływu podstawników na aromatyczność pierścieni pochodnych karbazolu. Związki te charakteryzują się dobrymi właściwościami optycznymi i fotoprzewodnictwem, stąd też są obiektem badań w inżynierii materiałowej. W pracy sprawdzono jak charakter elektronowy podstawnika, miejsce podstawienia oraz orientacja względem płaszczyzny pierścieni karbazolu ma wpływ na zmiany w n-elektronowej delokalizacji w obrębie całego układu karbazolu. Przeanalizowano podstawniki o charakterze elektrono-akceptorowym (-NO2) i elektrono-donorowym (-NH2) lokując je w pięciu pozycjach pierścienia karbazolowego w ułożeniu równoległym i prostopadłym. Na podstawie wartości i…

Public Organizations and Local Rural Development : an Empirical Analysis

2005

This paper describes an empirical approach designed and adopted to analyze and qualify the role of some public agencies devoted to rural development. These public organizations operate as critical agents in managing local public goods within a complex relation system functioning on a rural area. On the bases of the experiences and observations made on a case study in Central Italy, it emerges an analytical framework deriving from the correlation of an objective and subjective perspectives in the evaluation of these organizations’ performances. From these correlations, it derives a model to empirically classify these agencies evaluating also their potentials in creating integration, condensa…

Bounds on plastic strains for elastic plastic structures in plastic shakedown conditions

2007

The problem related to the computation of bounds on plastic deformations for structures in plastic shakedown condition (alternating plasticity) is studied. In particular, reference is made to structures discretized by finite elements constituted by elastic perfectly plastic material and subjected to a special combination of fixed and cyclic loads. The load history is known during the steady-state phase, but it is unknown during the previous transient phase; so, as a consequence, it is not possible to know the complete elastic plastic structural response. The interest is therefore focused on the computation of bounds on suitable measures of the plastic strain which characterizes just the fir…