981 resultados para Wannier-Stark
Resumo:
Análisis comparativo de los valores de la cultura empresarial en Grecia, España, Lituania y Austria. Para ello se presenta el modelo teórico de los valores de la cultura empresarial en Europa, la metodología de investigación adoptada en cada uno de estos países, el análisis de los resultados obtenidos en base al estudio piloto Leonardo da Vinci .
Resumo:
The influence of the basis set size and the correlation energy in the static electrical properties of the CO molecule is assessed. In particular, we have studied both the nuclear relaxation and the vibrational contributions to the static molecular electrical properties, the vibrational Stark effect (VSE) and the vibrational intensity effect (VIE). From a mathematical point of view, when a static and uniform electric field is applied to a molecule, the energy of this system can be expressed in terms of a double power series with respect to the bond length and to the field strength. From the power series expansion of the potential energy, field-dependent expressions for the equilibrium geometry, for the potential energy and for the force constant are obtained. The nuclear relaxation and vibrational contributions to the molecular electrical properties are analyzed in terms of the derivatives of the electronic molecular properties. In general, the results presented show that accurate inclusion of the correlation energy and large basis sets are needed to calculate the molecular electrical properties and their derivatives with respect to either nuclear displacements or/and field strength. With respect to experimental data, the calculated power series coefficients are overestimated by the SCF, CISD, and QCISD methods. On the contrary, perturbation methods (MP2 and MP4) tend to underestimate them. In average and using the 6-311 + G(3df) basis set and for the CO molecule, the nuclear relaxation and the vibrational contributions to the molecular electrical properties amount to 11.7%, 3.3%, and 69.7% of the purely electronic μ, α, and β values, respectively
Resumo:
Two common methods of accounting for electric-field-induced perturbations to molecular vibration are analyzed and compared. The first method is based on a perturbation-theoretic treatment and the second on a finite-field treatment. The relationship between the two, which is not immediately apparent, is made by developing an algebraic formalism for the latter. Some of the higher-order terms in this development are documented here for the first time. As well as considering vibrational dipole polarizabilities and hyperpolarizabilities, we also make mention of the vibrational Stark effec
Resumo:
A educação não pode se caracterizar como sendo algo que estabelece diferenças e prioridades levando-se em consideração as vantagens de grupos de alunos que possuem excelente estrutura familiar, melhores condições de vida e freqüentam escolas particulares, com toda infraestrutura de ensino e dotadas de recursos didáticos avançados em detrimento de uma maioria da população que freqüenta escola pública, recebe ensino de péssima qualidade e ainda tem que trabalhar para sobreviver. Mesmo que sejam questionadas, tais diferenças existem, estão comprovadas e identificadas nos diversos relatórios e dados a respeito da educação e do sistema educacional brasileiro, principalmente os de caráter público. Os reflexos das distorções sociais e das dificuldades de acesso à escola púbica retratam uma realidade cruel acerca de um percentual considerável de alunos que tentam fazer da educação um instrumento de melhoria da qualidade de vida, superação de obstáculos e das dificuldades enfrentadas com a exclusão social, se forem retratados os aspectos sócio-culturais e econômicos. Em um contexto que envolve a realidade educacional dos alunos da Unidade Escolar José Olimpio da Paz, as dificuldades são visíveis, entretanto a superação dos obstáculos e das dificuldades se dá pelo comprometimento dos alunos em participar ativamente do processo ensino-aprendizagem no intuito de melhorarem e aumentarem cada vez mais seus conhecimentos, ao mesmo tempo em que o envolvimento dos professores em promover educação com qualidade, fazendo de sua prática pedagógica um instrumento de luta pelas transformações educacionais, culturais e sociais da comunidade, com foco direcionado para a melhoria da qualidade de vida dos alunos através da educação e da aprendizagem contribui, também e de modo decisivo, para a obtenção de resultados positivos através dos quais todos tenham razões de ganho com o envolvimento compromissado com educação de qualidade.
Resumo:
Two stark reminders of the difficulties that people on the move encounter in the Mediterranean have been grabbing headlines recently: the so-called ‘left-to-die’ boat report and the ground-breaking Hirsi judgment. These two instances present the worst of both worlds: the first concerns a migrant boat that was ignored altogether, resulting in many deaths, whereas the second concerns a migrant boat being intercepted but subsequently dealt with in a way that contradicts Europe’s human rights standards. These two cases are neither isolated nor incidental. Instead they are of wider concern to the EU and reminders of structural deficiencies in Europe’s approach to people on the move in the Mediterranean. This paper identifies those cross-cutting deficiencies and proposes recommendations to correct them.
Resumo:
Large firms contribute disproportionately to the economic performance of countries: they are more productive, pay higher wages, enjoy higher profits and are more successful in international markets. The differences between European countries in terms of the size of their firms are stark. Firms in Italy and Spain, for example, are on average 40 percent smaller than firms in Germany. The low average firm size translates into a chronic lack of large firms. In Italy and Spain, a mere 5 percent of manufacturing firms have more than 250 employees, compared to a much higher 11 percent in Germany. Understanding the roots of these differences is key to improving the economic performance of Europe’s lagging economies. So why is there so much variation in firm size in different European countries? What are the barriers that keep firms in some countries from growing? And which policies are likely to be most effective in breaking down those barriers? This policy report aims to answer these questions by developing a quantitative model of the seven European countries covered by the EFIGE survey (Austria, France, Germany, Hungary, Italy, Spain and the UK). The EFIGE survey asked 14,444 firms in those countries about their performance, their modes of internationalisation, their staffing decisions, their financing structure, and their competitive environment, among other topics.
Resumo:
The microwave spectra of 2-aminopyridine-NH2, -ND2, and of both of the two possible -NHD molecules have been observed and assigned in the 0+ vibrational state of the amino group inversion vibration; the assignment for three of the molecules in the 0− state is also made. From intensity measurements the 0+-0− splitting is estimated to be 135 ± 25 cm−1 for the -NH2 molecule and 95 ± 30 cm−1 for the -ND2 molecule. The rotational constants are interpreted in terms of a structure in which the amino group is bent about 32° out of the molecular plane, the c coordinates of the two amino H atoms being 0.21 and 0.28 Å. Stark effect measurements give a dipole moment of about 0.9 D which is almost entirely in the b axis, and which changes quite significantly between the 0+ and 0− states.