Aerosol-assisted metallo-organic chemical vapour deposition of Bi2Se3 films using single-molecule precursors: the crystal structure of bismuth(m) dibutyldiselenocarbamate

The complexes [Bi{Se2CN(C2H5)2}3], [Bi{Se2CN(C4H9)2}3], [Bi{Se2CN(CH3)(C4H9)}3] and [Bi{Se2CN(CH3)(C6H13)}3] have been synthesized and characterized structurally using IR, 1H and 13C NMR. In addition, the crystal structure of [Bi{Se2CN(C4H9)2}3] was determined by single-crystal X-ray diffraction, showing the bismuth centre coordinated to three dialkyldiselenocarbamate ligands through the selenium donor atoms. The Bi(III) compounds were used as precursors for the deposition of Bi2Se3 films on glass substrates through aerosol-assisted metallo-organic chemical vapour deposition (AA-MOCVD)

Deutsche Fachsprachen : alte und neue Erfahrungen mit dem Begriff 'Kultur' in den Geisteswissenschaften und im Bereich Deutsch als Fremdsprache

In the last few years, the areas of study of German as Foreign Language and German for Specific Purposes have evidently made an inflationary, and sometimes even inadequate use of concepts related to the adjectives 'cultural' and 'intercultural'. The concepts have often been used so as to serve only to instigate the increase, permanency and dissemination of stereotypes and pre-conceptions. In the Winter 2006/07 Semester, a course called "Fachsprachen und Kultur" was offered on the way the concepts of culture are approached in different fields of study. This paper presents the conclusions of some of the participants on the use of the concept in their primary or secondary areas. The results show that it is urgent and necessary to examine the concepts of culture used in our field of study so that stereotypes do not become the basis for a didactics of German as a Foreign Language.Nas áreas de estudos Alemão como Língua Estrangeira e Alemão para Fins Específicos é evidente, nos últimos anos, o uso inflacionário e até, às vezes, impróprio, de conceitos relacionados aos adjetivos cultural e intercultural. Freqüentemente, os conceitos são usados de tal forma que apenas servem para fomentar o crescimento, a fixação e a difusão de estereótipos e preconceitos. No semestre de inverno 2006/07 foi oferecido um curso denominado "Fachsprachen und Kultur" (Magisterstudiengang Deutsch als Fremdsprache), no qual deveriam ser estudados os conceitos de cultura usados nas diferentes disciplinas. Aqui são apresentadas as conclusões de alguns participantes sobre o uso do conceito nas suas áreas principais ou secundárias. Os resultados mostram que se faz urgente e necessário ocupar-se com os conceitos de cultura que vigoram em nossa disciplina, para que estereótipos não se tornem a base de uma didática do Alemão como Língua Estrangeira

Fractional ℏ\hbar-scaling for quantum kicked rotors without cantori

Previous studies of quantum delta-kicked rotors have found momentum probability distributions with a typical width (localization length $L$) characterized by fractional $\hbar$-scaling, ie $L \sim \hbar^{2/3}$ in regimes and phase-space regions close to `golden-ratio' cantori. In contrast, in typical chaotic regimes, the scaling is integer, $L \sim \hbar^{-1}$. Here we consider a generic variant of the kicked rotor, the random-pair-kicked particle (RP-KP), obtained by randomizing the phases every second kick; it has no KAM mixed phase-space structures, like golden-ratio cantori, at all. Our unexpected finding is that, over comparable phase-space regions, it also has fractional scaling, but $L \sim \hbar^{-2/3}$. A semiclassical analysis indicates that the $\hbar^{2/3}$ scaling here is of quantum origin and is not a signature of classical cantori.Comment: 5 pages, 4 figures, Revtex, typos removed, further analysis added, authors adjuste

BitTorrent based transmission of real-time scalable video over P2P networks

The number of software applications available on the Internet for distributing video streams in real time over P2P networks has grown quickly in the last two years. Typical this kind of distribution is made by television channel broadcasters which try to make their content globally available, using viewer's resources to support a large scale distribution of video without incurring in incremental costs. However, the lack of adaptation in video quality, combined with the lack of a standard protocol for this kind of multimedia distribution has driven content providers to basically ignore it as a solution for video delivery over the Internet. While the scalable extension of the H.264 encoding (H.264/SVC) can be used to support terminal and network heterogeneity, it is not clear how it can be integrated in a P2P overlay to form a large scale and real time distribution. In this paper, we start by defining a solution that combines the most popular P2P file-sharing protocol, the Bit Torrent, with the H.264/SVC encoding for a real-time video content delivery. Using this solution we then evaluate the effect of several parameters in the quality received by peers