Search results for "RAM"
showing 10 items of 35643 documents
Pressure- and temperature-induced valence tautomeric interconversion in a o-dioxolene adduct of a cobalt-tetraazamacrocycle complex
2001
An electronic switch at the molecular level has been realized by using a class of ionic compounds of the formula [Co(L)(diox)]Y (L = tetraazamacrocyclic ligand, Y = mononegative anion). Such compounds undergo temperature- and pressure-induced intramolecular one-electron transfer equilibria. The transition temperature of interconversion varies with the nature of the counterions Y (Y = PF6, BPh4, I). Surprisingly the effect of the anion on the transition temperature is not only governed by its volume but also by its coulombic interaction.
A M�ssbauer and ESR study of LiNbO3-Fe2O3 for low Fe2O3 concentrations
1989
Samples of the system LiNbO3-Fe2O3 prepared by water quenching and by the double-roller quenching method in the range up to 24 mol% Fe2O3 were investigated by Mossbauer and ESR spectroscopy. In the water quenched samples up to 11 mol% Fe2O3 only the Fe3+ and the Fe2+ valence states could be detected. The Fe2+ concentration decreased with increasing Fe2O3 content. Above 11 mol% Fe2O3 magnetically split Mossbauer spectra indicated the presence of Fe2O3 clusters. The isomer shift values of Fe3+ as a function of Fe2O3 concentration showed jumps at 6 and 11 mol% Fe2O3, whereas no significant changes could be detected in the quadrupole splitting values. The ESR data already exhibited the existenc…
Dimensional encapsulation of I− I 2 I− in an organic salt crystal matrix
2010
Bis(trimethylammonium)hexane diiodide encapsulates iodine from solution and through a gas/solid reaction yielding in a predictable and controllable manner the selective formation of the rare polyiodide species I(-)...I-I...I(-), which matches in length to the chosen dication.
Substituent Effects on the [N−I−N]+ Halogen Bond
2016
We have investigated the influence of electron density on the three-center [N–I–N]+ halogen bond. A series of [bis(pyridine)iodine]+ and [1,2-bis((pyridine-2-ylethynyl)benzene)iodine]+ BF4– complexes substituted with electron withdrawing and donating functionalities in the para-position of their pyridine nitrogen were synthesized and studied by spectroscopic and computational methods. The systematic change of electron density of the pyridine nitrogens upon alteration of the para-substituent (NO2, CF3, H, F, Me, OMe, NMe2) was confirmed by 15N NMR and by computation of the natural atomic population and the π electron population of the nitrogen atoms. Formation of the [N–I–N]+ halogen bond re…
Effects of magnesium chloride on the contractile response of uterus to several agonists in Ca-free solution
1987
Abstract The effects of MgCl2 on the oestrogen-dominated rat uterus have been examined. Tissues were preincubated in a Ca2+- and Mg2+-free medium containing 3 mM EDTA. Most experiments were subsequently performed in a similar medium containing either no EDTA or EDTA (1 mM). When MgCl2 was added cumulatively (1–32 mM) no contractile responses were obtained in Ca,Mg-free medium or in Ca,Mg-free high K+ solution. When 2 mM CaCl2 as added, a sustained contraction was obtained. Subsequent addition of cumulative concentrations of MgCl2 caused concentration-dependent relaxation. Oxytocin, 2 μM, produced a small and sustained contraction in a Ca,Mg-free medium. Addition of MgCl2, 2 mM, increased th…
Novel supramolecular affinity materials based on (−)-isosteviol as molecular templates
2013
The readily available ex-chiral-pool building block (−)-isosteviol was combined with the C3-symmetric platforms hexahydroxytriphenylene and hexaaminotriptycene providing large and rigid molecular architectures. Because of the persistent cavities these scaffolds are very potent supramolecular affinity materials for head space analysis by quartz crystal microbalances. The scaffolds serve in particular as templates for tracing air-borne arenes at low concentration. The affinities of the synthesized materials towards different air-borne arenes were determined by 200 MHz quartz crystal microbalances.
Feedback Linearizing Control of Induction Motor Considering Magnetic Saturation Effects
2015
This paper presents an input-output feedback linearization (FL) control technique for rotating induction motors, which takes into consideration the magnetic saturation of the iron core. Starting from a new formulation of the dynamic model taking into consideration the magnetic saturation expressed in a space-state form in the rotor-flux-oriented reference frame, the corresponding FL technique has been developed. To this aim, a particular care has been given to the choice of nonlinear functions interpolating the magnetic parameters versus the rotor magnetizing current and the corresponding magnetic characteristic. The proposed FL technique has been tested experimentally on a suitably develop…
La deriva pornonarcisista de l’autorepresentació a Instagram
2022
Les xarxes socials digitals han passat a ser un element central en la vida quotidiana de la nostra societat, especialment entre els joves. No són només una finestra al món, o una font infinita d’informació, sinó que s’estan convertint en un mitjà de construcció dels relats de vida, on els individus exposen una versió escollida de forma aparentment conscient de la seva personalitat, la seva estètica i les seves opinions. Tot això, a totes hores i sense els condicionants de fer-ho de forma física o presencial amb el públic a qui va dirigit. S’és protagonista d’un flux d’informació bidireccional des del “pseudònim” d’usuari i el mar de l’anonimat virtual. Aquest procés de construcció d’una ide…
Actualización de las estrategias docentes en Psicobiología a través de las redes sociales
2020
La demanda de nuevas estrategias de aprendizaje, junto con el avance de las nuevas tecnologías en un mundo cada vez más conectado y globalizado, hace necesario el desarrollo de nuevas competencias y habilidades en estudiantes y profesores que permitan modernizar el proceso de enseñanza-aprendizaje. Actualmente, en las aulas universitarias se detecta una carencia en el conocimiento y manejo de herramientas que permiten conseguir una información fiable y veraz sobre temas científicos. Las redes sociales se han convertido en una de las principales fuentes de información de las nuevas generaciones, que las usan a diario con distintas finalidades, principalmente de manera lúdica. Sin embargo, és…
Internationalisation in higher education: A comparative view of cross-border type 1 & 2 education and their impact on developing and developed countr…
2014
Este trabajo examina que significa 'la internacionalización de la educación superior' y como la globalización, en particular, la internacionalización han influencionado la educaciñon transnacional y los efectos que las polítcas comerciales y económias han tenido en la movilidad de estudiantes y en la movilidad de programas e instituciones a lo largo de estos últimos años. Estos dos tipos de movilidades han sido muy relevantes en el desarrollo nacional. Por medio de la investigacion cualitativa y cuantitativa, resulta evidente que para los países en desarrollo que han tenido dificultad en satisfacer las exigencias y necesidades de educación superior de su población, la educación transnaciona…