Topological defects and misfit strain in magnetic stripe domains of lateral multilayers with perpendicular magnetic anisotropy

Stripe domains are studied in perpendicular magnetic anisotropy films nanostructured with a periodic thickness modulation that induces the lateral modulation of both stripe periods and inplane magnetization. The resulting system is the 2D equivalent of a strained superlattice with properties controlled by interfacial misfit strain within the magnetic stripe structure and shape anisotropy. This allows us to observe, experimentally for the first time, the continuous structural transformation of a grain boundary in this 2D magnetic crystal in the whole angular range. The magnetization reversal process can be tailored through the effect of misfit strain due to the coupling between disclinations in the magnetic stripe pattern and domain walls in the in-plane magnetization configuration

Estudio de pilotos automáticos enfocados en la configuración de ala volante para vehículos aéreos no tripulados

Este artículo presenta una revisión de los sistemas de piloto automáticos para vehículos aéreos no tripulados (UAV). Se muestra un estudio de los productos comerciales que se pueden encontrar actualmente en el mercado, se incluyen sistemas open source y se hace una comparación entre las diferentes arquitecturas a nivel de requerimientos básicos a nivel de sensores, capacidad de procesamiento, tamaño, peso y precios. Este estudio se realiza con el fin de analizar la arquitectura básica que tienen estos tipos de sistemas enfocados hacia la configuración de un UAV de tipo ala volante

A General Rhodium Catalyst for the Deuteration of Boranes and Hydrides of the Group 14 Elements

Pinacolborane, catecholborane, triethylsilane, triphenylsilane, dimethylphenylsilane, 1, 1, 1, 3, 5, 5, 5-heptamethyltrisiloxane, triethylgermane, triphenylgermane, and triphenylstannane deuterated at the heteroatom position have been catalytically prepared in 50-70% isolated yield, through H/D exchange between the D2 molecule and the respective boranes and hydrides of the group 14 elements, in the presence of the rhodium(I)-monohydride catalyst precursor RhH{¿3-P, O, P-[xant(PiPr2)2]} (xant(PiPr2)2 = 9, 9-dimethyl-4, 5-bis(diisopropylphosphino)xanthene)

Identificación y descripción de procesos reales en la universidad EAFIT bajo la perspectiva de sistemas dinámicos

Este trabajo está enfocado hacia el estudio de los sistemas dinámicos en la universidad EAFIT, a partir de visitas realizadas a los laboratorios de la universidad, haciendo una breve descripción de máquinas y procesos bajo la teoría de los sistemas dinámicos, teniendo en cuenta las características más importantes de un sistema dinámico como lo son: entrada, salidas, posibles perturbaciones. Dejando así un importante apoyo para quienes después se puedan interesar tanto en describir como llegar a un posible control de algunos de los procesos, dada la necesidad en la universidad por personas interesadas en este tipo de estudios, pues en las visitas realizadas a dichos laboratorios se pudo observar la falta de interés tanto de los estudiantes como de la misma universidad para realizar un mejor estudio de los procesos, viendo así como muchos de los procesos no son desarrollados de la mejor manera. Hecha la descripción de los procesos, se procederá a un estudio mucho más detallado de dos de estos procesos reales empezando con la modelación y simulación del mismo, bajo la teoría de los sistemas lineales usando como herramienta de simulación MATLAB SIMULINK

Social Support Seeking And Early Adolescent Depression And Anxiety Symptoms: The Moderating Role Of Rumination

This study examined how social support seeking and rumination interacted to predict depression and anxiety symptoms 6 months later in early adolescents (N = 118; 11-14 years at baseline). We expected social support seeking would be more helpful for adolescents engaging in low rather than high levels of rumination. Adolescents self-reported on all measures at baseline, and on depression and anxiety symptoms 6 months later. Social support seeking predicted fewer symptoms of depression and anxiety at low rumination levels but was not associated with benefits as rumination increased. For depression symptoms, social support seeking predicted more symptoms at high rumination levels. Results were stronger for emotion-focused than problem-focused support seeking and for depression compared with anxiety symptoms. These findings suggest that cognitive risk factors like rumination may explain some inconsistencies in previous social support literature, and highlight the importance of a nuanced approach to studying social support seeking

Crossed-ratchet effects and domain wall geometrical pinning

The motion of a domain wall in a two dimensional medium is studied taking into account the internal elastic degrees of freedom of the wall and geometrical pinning produced both by holes and sample boundaries. This study is used to analyze the geometrical conditions needed for optimizing crossed ratchet effects in periodic rectangular arrays of asymmetric holes, recently observed experimentally in patterned ferromagnetic films. Geometrical calculations and numerical simulations have been used to obtain the anisotropic critical fields for depinning flat and kinked walls in rectangular arrays of triangles. The aim is to show with a generic elastic model for interfaces how to build a rectifier able to display crossed ratchet effects or effective potential landscapes for controlling the motion of interfaces or invasion fronts.Comment: 13 pages, 18 figure

Ammonia Borane Dehydrogenation Promoted by a Pincer-Square-Planar Rhodium(I) Monohydride: A Stepwise Hydrogen Transfer from the Substrate to the Catalyst

The pincer d8-monohydride complex RhH{xant(PiPr2)2} (xant(PiPr2)2 = 9, 9-dimethyl-4, 5-bis(diisopropylphosphino)xanthene) promotes the release of 1 equiv of hydrogen from H3BNH3 and H3BNHMe2 with TOF50% values of 3150 and 1725 h–1, to afford [BH2NH2]n and [BH2NMe2]2 and the tandem ammonia borane dehydrogenation–cyclohexene hydrogenation. DFT calculations on the ammonia borane dehydrogenation suggest that the process takes place by means of cis-¿2-PP-species, through four stages including: (i) Shimoi-type coordination of ammonia borane, (ii) homolytic addition of the coordinated H–B bond to afford a five-coordinate dihydride-boryl-rhodium(III) intermediate, (iii) reductive intramolecular proton transfer from the NH3 group to one of the hydride ligands, and (iv) release of H2 from the resulting square-planar hydride dihydrogen rhodium(I) intermediate