Design and synthesis of quasi-diastereomeric molecules with unchanging central, regenerating axial and switchable helical chirality via cleavage and formation of Ni(II)–O and Ni(II)–N coordination bonds

9 p.

Spin-helical Dirac states in graphene induced by polar-substrate surfaces with giant spin-orbit interaction: a new platform for spintronics

Spintronics, or spin electronics, is aimed at efficient control and manipulation of spin degrees of freedom in electron systems. To comply with demands of nowaday spintronics, the studies of electron systems hosting giant spin-orbit-split electron states have become one of the most important problems providing us with a basis for desirable spintronics devices. In construction of such devices, it is also tempting to involve graphene, which has attracted great attention because of its unique and remarkable electronic properties and was recognized as a viable replacement for silicon in electronics. In this case, a challenging goal is to lift spin degeneracy of graphene Dirac states. Here, we propose a novel pathway to achieve this goal by means of coupling of graphene and polar-substrate surface states with giant Rashba-type spin-splitting. We theoretically demonstrate it by constructing the graphene@BiTeCl system, which appears to possess spin-helical graphene Dirac states caused by the strong interaction of Dirac and Rashba electrons. We anticipate that our findings will stimulate rapid growth in theoretical and experimental investigations of graphene Dirac states with real spin-momentum locking, which can revolutionize the graphene spintronics and become a reliable base for prospective spintronics applications.

Self-Similarity and helical symmetry in vortex generator flow simulations

According to experimental observations, the vortices generated by vortex generators have previously been observed to be self-similar for both the axial (u(z)) and azimuthal (u(circle minus)) velocity profiles. Further, the measured vortices have been observed to obey the criteria for helical symmetry. This is a powerful result, since it reduces the highly complex flow to merely four parameters. In the present work, corresponding computer simulations using Reynolds-Averaged Navier-Stokes equations have been carried out and compared to the experimental observations. The main objective of this study is to investigate how well the simulations can reproduce the physics of the flow and if the same analytical model can be applied. Using this model, parametric studies can be significantly reduced and, further, reliable simulations can substantially reduce the costs of the parametric studies themselves.

La actividad del World Café, una herramienta para la evaluación y desarrollo de los valores en el deporte escolar

[ES] El presente trabajo presenta una experiencia aplicada que pretende conocer las opiniones, de los agentes sociales que rodean a los jóvenes deportistas, para la promoción de valores. A través de la actividad del World Café, los agentes sociales implicados en el deporte escolar aportaron orientaciones enfocadas a mejorar la calidad educativa del deporte. Un grupo de 56 participantes [padres/madres (8), árbitros (8), profesores de educación física (8), entrenadores (8), deportistas de élite (8), deportistas escolares (8) y representantes institucionales (8)] debatieron, desde su perspectiva, cómo consideraban que podían ayudar en la promoción de valores en los contextos deportivos escolares en los que participan. Entre los resultados más relevantes destacan, la necesidad de concretar desde el propio centro escolar los valores que se pretenden promocionar a través del deporte; en segundo lugar, la importancia de llevar a cabo una coordinación entre los agentes directos que rodean a los jóvenes deportistas; y finalmente, llevar a cabo una formación dirigida a monitores y padres/madres, que les permita adquirir herramientas adecuadas para la promoción de valores.