Search results for "Theory"
showing 10 items of 24627 documents
Electron-phonon interaction in flat-band superconductivity
2017
Parhaiten tunnettu suprajohtavuuden syntymekanismi perustuu fononien välittämään vetovoimaan elektronien välillä. Tässä tutkielmassa tutkin fononien välittämää suprajohtavuutta systeemeissä, jossa elektronivyöt ovat tasomaisia. Tasovyöllä elektronien dispersio on erittäin heikko, jolloin tilatiheys on tavanomaista suurempi. Tämän takia suprajohtavuus tasovyöllä on tavanomaista voimakkaampi silloin kun elektronien välinen vetovoima on heikko. Eliashbergin teoria on elektroni–fononi-suprajohtavuuden teoria, joka ottaa luonnollisella tavalla fononien äärellisen nopeuden huomioon elektronien välisessä vuorovaikutuksessa. Pohjustuksena tasovyösuprajohtavuuteen perehdyn Eliashbergin teoriaan ensi…
The Hexameric Resorcinarene Capsule as a Brønsted Acid Catalyst for the Synthesis of Bis(heteroaryl)methanes in a Nanoconfined Space
2019
Herein, we show that the hexameric resorcinarene capsule C is able to catalyze the formation of bis(heteroaryl)methanes by reaction between pyrroles or indoles and carbonyl compounds (α-ketoesters or aldehydes) in excellent yields and selectivity. Our results suggest that the capsule can play a double catalytic role as a H-bond catalyst, for the initial activation of the carbonyl substrate, and as a Bronsted acid catalyst, for the dehydration of the intermediate alcohol.
Governing at the frontier of the European Commission : the case of seconded national officials
2005
Studies of executive institutions have largely dealt separately with national and international executive institutions (IEIs). This study unpacks and repacks four conflicting decision-making dynamics that unfolds at the frontier of IEIs – that is, at the institutional rim where national and international executive institutions meet, interact and collide. The empirical laboratory utilised is seconded national experts in the European Commission. The survey and interview data presented demonstrates that the decision-making behaviour of seconded national experts includes a mix of departmental (portfolio), epistemic (expert) and supranational behaviour. The suspicion early voiced by Coombes (197…
International executives : transformative bureaucracies or Westphalian orders?
2004
Public Administration is in an era of change. This paper studies one under-researched part of public administration, the executive arms of International Governmental Organizations (IGOs). These are referred to as International Executives (IEs) and provide a conceptual mapping and empirical illustrations of three important dynamics of IEs – intergovernmental, supranational and transgovernmental dynamics. The paper offers a middle-range organization theory perspective that suggests five independent variables that affect the behavior and roles of IE civil servants. The variables are (i) the organizational properties of IEs, (ii) the degrees of institutionalization of IEs, (iii) the recruitment…
Re-discovering international executive institutions
2004
Public Administration is in an era of change. This article aims at re-discovering one underresearched part of public administration, the executive arms of International Governmental Organizations (IGOs). These are referred to as International Executives (IEs). The article provides a conceptual mapping and an empirical illustration of three important dynamics of IEs – intergovernmental, supranational and transgovernmental dynamics. The study also offers a middle-range organization theory perspective that suggests five independent variables that foster the advent of supranational and transgovernmental behavior and roles among IE civil servants. The variables suggested are (H1) the organizatio…
Engineered surface waves in hyperbolic metamaterials
2013
We analyzed surface-wave propagation that takes place at the boundary between a semi-infinite dielectric and a multilayered metamaterial, the latter with indefinite permittivity and cut normally to the layers. Known hyperbolization of the dispersion curve is discussed within distinct spectral regimes, including the role of the surrounding material. Hybridization of surface waves enable tighter confinement near the interface in comparison with pure-TM surface-plasmon polaritons. We demonstrate that the effective-medium approach deviates severely in practical implementations. By using the finite-element method, we predict the existence of long-range oblique surface waves. This research was fu…
Automatic surrogate modelling technique selection based on features of optimization problems
2019
A typical scenario when solving industrial single or multiobjective optimization problems is that no explicit formulation of the problem is available. Instead, a dataset containing vectors of decision variables together with their objective function value(s) is given and a surrogate model (or metamodel) is build from the data and used for optimization and decision-making. This data-driven optimization process strongly depends on the ability of the surrogate model to predict the objective value of decision variables not present in the original dataset. Therefore, the choice of surrogate modelling technique is crucial. While many surrogate modelling techniques have been discussed in the liter…
Ecology Approach in Education and Health Care
2017
Abstract In the 21st century, numerous complex challenges in education and health care have come to the fore, among them: 1) how to implement the ecological approach in the education process and health care practice; 2) how to implement study programmes in line with the education trends for sustainable development and the process of formation and development of the ecological competence. The results of this research refer only to the content analysis of the essays written by the first and second year students of the programs in Nursing and Medicine on completing the study course The Ecological Approach in Patient Care. To increase the credibility and validity of the obtained results of the …
A multifractal approach of central place theory for sustainable planning
2013
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Investigation of the elastic and inelastic scattering of 4He from 11B in the energy range 29-50.5 MeV
2018
We have measured the angular distributions for the elastic and inelastic scattering of 4He from 11B in the isochronous cyclotron U-150 M INP RK. The extracted α-particles beam has been accelerated to energy 29 MeV and then directed to 11B target. The experimental results were analyzed within the framework of both the optical model using different complex potential and the double folding potential obtained with different density-dependent NN interactions which give the corresponding values of the nuclear incompressibility K in the Hartree-Fock calculation of nuclear matter. peerReviewed