Codename One: "write once, run anywhere"

Codename One est un plug-in pour NetBeans et Eclipse sorti récemment. Il permet de développer en Java, avec un seul et même code, des applications multiplateformes. Nous avons tout d’abord étudié le produit, afin de comprendre comment il fonctionne et de déterminer les inconvénients/avantages qu’il présente. Puis nous l’avons comparé à des produits similaires. Finalement, nous avons mis en œuvre une application avec trois fenêtres, une base de données et un web service, afin d’implémenter les caractéristiques de base de la plupart des applications mobiles. Ceci nous a permis d’évaluer Codename One et d’en donner une critique personnelle

Quantum confinement in Si and Ge nanostructures: Effect of crystallinity

We look at the relationship between the preparation method of Si and Ge nanostructures (NSs) and the structural, electronic, and optical properties in terms of quantum confinement (QC). QC in NSs causes a blue shift of the gap energy with decreasing NS dimension. Directly measuring the effect of QC is complicated by additional parameters, such as stress, interface and defect states. In addition, differences in NS preparation lead to differences in the relevant parameter set. A relatively simple model of QC, using a `particle-in-a-box'-type perturbation to the effective mass theory, was applied to Si and Ge quantum wells, wires and dots across a variety of preparation methods. The choice of the model was made in order to distinguish contributions that are solely due to the effects of QC, where the only varied experimental parameter was the crystallinity. It was found that the hole becomes de-localized in the case of amorphous materials, which leads to stronger confinement effects. The origin of this result was partly attributed to differences in the effective mass between the amorphous and crystalline NS as well as between the electron and hole. Corrections to our QC model take into account a position dependent effective mass. This term includes an inverse length scale dependent on the displacement from the origin. Thus, when the deBroglie wavelength or the Bohr radius of the carriers is on the order of the dimension of the NS the carriers `feel' the confinement potential altering their effective mass. Furthermore, it was found that certain interface states (Si-O-Si) act to pin the hole state, thus reducing the oscillator strength.Comment: arXiv admin note: substantial text overlap with arXiv:1111.201

Ward identities for the Anderson impurity model: derivation via functional methods and the exact renormalization group

Using functional methods and the exact renormalization group we derive Ward identities for the Anderson impurity model. In particular, we present a non-perturbative proof of the Yamada-Yosida identities relating certain coefficients in the low-energy expansion of the self-energy to thermodynamic particle number and spin susceptibilities of the impurity. Our proof underlines the relation of the Yamada-Yosida identities to the U(1) x U(1) symmetry associated with particle number and spin conservation in a magnetic field.Comment: 8 pages, corrected statements about infintite flatband limi

Personality profiles of young chess players

Although the game of chess has often featured in psychological research, we know very little about people who play chess, especially about children who take up chess as a hobby. This study presents the personality profiles as measured with the Big Five model (BFQ-C; Barbaranelli et al., 2003) of 219 young children who play chess and 50 of their peers who do not. Children who score higher on Intellect/openness and Energy/extraversion are more likely to play chess while children who score higher on Agreeableness are less likely to be attracted to chess. Boys with higher scores on Agreeableness are less likely to take up chess than boys with lower scores. Considering that girls score higher on Agreeableness, this factor may provide one of the possible reasons why more boys are interested in chess. Although none of the Big Five factors were associated with self-reported skill level, a sub-sample of 25 elite players had significantly higher scores on Intellect/openness than their weaker chess playing peers