Generic helical edge states due to Rashba spin-orbit coupling in a topological insulator

We study the helical edge states of a two-dimensional topological insulator without axial spin symmetry due to the Rashba spin-orbit interaction. Lack of axial spin symmetry can lead to so-called generic helical edge states, which have energy-dependent spin orientation. This opens the possibility of inelastic backscattering and thereby nonquantized transport. Here we find analytically the new dispersion relations and the energy dependent spin orientation of the generic helical edge states in the presence of Rashba spin-orbit coupling within the Bernevig-Hughes-Zhang model, for both a single isolated edge and for a finite width ribbon. In the single-edge case, we analytically quantify the energy dependence of the spin orientation, which turns out to be weak for a realistic HgTe quantum well. Nevertheless, finite size effects combined with Rashba spin-orbit coupling result in two avoided crossings in the energy dispersions, where the spin orientation variation of the edge states is very significantly increased for realistic parameters. Finally, our analytical results are found to compare well to a numerical tight-binding regularization of the model.

Solderjet bumping technique used to manufacture a compact and robust green solid-state laser

Solder-joining using metallic solder alloys is an alternative to adhesive bonding. Laser-based soldering processes are especially well suited for the joining of optical components made of fragile and brittle materials such as glasses, ceramics and optical crystals due to a localized and minimized input of thermal energy. The Solderjet Bumping technique is used to assemble a miniaturized laser resonator in order to obtain higher robustness, wider thermal conductivity performance, higher vacuum and radiation compatibility, and better heat and long term stability compared with identical glued devices. The resulting assembled compact and robust green diode-pumped solid-state laser is part of the future Raman Laser Spectrometer designed for the Exomars European Space Agency (ESA) space mission 2018.

Los proverbios de animales en árabe clásico: análisis, estudio comparativo y equivalencias en español

This study entitled «Classical Arabic proverbs: analysis, comparative study and equivalence in Spanish», aims on one hand, to display the multiple problems we face when translating proverbs between Arabic and Spanish, and on the other hand, offers an updated check up of the proverbs uses as well as an analysis of the equivalence between proverbs. It was an arduous task looking for reference works which were of interest to our research both in Arabic and Spanish. We consulted many references but if we were to cite the most important ones, we would talk about works such as Magma alamtal by al-Maydani, which constituted the base we relied on in the analytical part of our work. Also of interest was Hayatu Al-Hayauani l-al-Kubra, from ad-Dummayri and his other work Mungid al-lugati w al-a'lam; as well as Ğamharat al-amtal by Abū Hilāl Al-‘Askarī and Ğamharat al-amtal al-baġdadiyya by‘Abd ar-Rahman Tikritī. As for the references in Spanish, we relied on Martinez Kleiseŕs Ideological General Spanish Proverbs; as well as 1001 Spanish sayings and their correspondence in eight languages from Julia Seville Muñoz and Ortiz de Urbina; also, Introduction to the study of fixed expressions by Julio Casares; Vocabulary of proverbs and proverbial phrases (1627-2000) by G. Correas; Dictionnary of sayings by Campos and Barella; the famous The Ingenious Gentleman Don Quixote of La Mancha by Miguel de Cervantes; the work of Sebastián Orozco de Covarrubias Treasure of Castilian Spanish; as well as Sayings and Proverbs in Romance from Hernán Núñez; or Over 21,000 Castilian Sayings not contained in the Large Collection of the Master Gonzalo Correas by Rodriguez Marín. Our work covered two main levels: a descriptive empirical area that included a historical approach with a definition of the different terms related to the proverbs used in our study. The other level is analytical which, besides holding our personal stamp, has been executed through a rigorous study of the three major aspects of our research: analysis, translation and equivalence of the proverb. We started by making a brief description of the empirical part we have divided into several sections, each devoted to the study of one particular aspect...