Particle growing mechanisms in Ag-ZrO2 and Au-ZrO2 granular films obtained by pulsed laser deposition

Thin films consisting of Ag and Au nanoparticles embedded in amorphous ZrO2 matrix were grown by pulsed laser deposition in a wide range of metal volume concentrations in the dielectric regime (0.08<x(Ag)<0.28 and 0.08<x(Au)<0.52). High resolution transmission electron microscopy (TEM) showed regular distribution of spherical Au and Ag nanoparticles having very sharp interfaces with the amorphous matrix. Mean particle size determined from X-ray diffraction agreed with direct TEM observation. The silver mean diameter increases more abruptly with metal volume content than that corresponding to gold particles prepared under the same conditions. Two mechanisms of particle growing are observed: nucleation and particle coalescence, their relative significance being different in both granular systems, which yields very different values of the percolation threshold (xc(Ag)~0.28 and xc(Au)~0.52).Comment: 6 figure

Transitie van een psychogeriatrische dagbehandeling in het verpleeghuis naar een laagdrempelige dagbehandeling in de wijk: een pilotonderzoek

Achtergrond In deze studie wordt de transitie van een reguliere psychogeriatrische dagbehandeling in het verpleeghuis naar laagdrempelige psychogeriatrische dagbehandeling met mantelzorgondersteuning (LPD-plus MO) in de wijk op de voet gevolgd. Het bewezen effectieve Model Ontmoetingscentra vormde het uitgangspunt bij de transitie. Methode Door middel van kwalitatieve analyse van documenten en interviews met sleutelfiguren (n = 11) worden factoren opgespoord die de overgang van de oude naar de nieuwe vorm van dagbehandeling bevorderen of belemmeren. Bij deelnemers en mantelzorgers die langer dan 6 maanden gebruik maken van het ondersteuningsaanbod wordt de tevredenheid over het nieuwe aanbod gepeild. Resultaten Verschillende kenmerken van LPD-plus MO blijken de samenwerking met andere zorg- en welzijnsaanbieders in de regio te bevorderen, zoals: de laagdrempelige locatie, de sociale integratie in de buurt en de focus op gecombineerde ondersteuning van zowel de persoon met dementie als de mantelzorger. Een goede samenwerking met andere zorg- en welzijnsorganisaties, en een geschikte locatie vergemakkelijken de implementatie. De aanwezigheid van concurrerend aanbod in de regio, zoals ontmoetingscentra voor mensen met dementie en hun mantelzorgers, belemmeren de werving van deelnemers voor de LPDplus MO. Deelnemers en mantelzorgers zijn over het algemeen tevreden over het ondersteuningsprogramma. Conclusie en discussie De transitie is succesvol verlopen en levert andere reguliere dagbehandelingen tips op voor de transitie naar LPD-plus MO

Tunneling magnetoresistance in Co-ZrO2 granular thin films

Granular films composed of well defined nanometric Co particles embedded in an insulating ZrO2 matrix were prepared by pulsed laser depositon in a wide range of Co volume concentrations 0.15 x 0.43. High-resolution transmission electron microscopy TEM showed very sharp interfaces between the crystalline particles and the amorphous matrix. Narrow particle size distributions were determined from TEM and by fitting the low-field magnetic susceptibility and isothermal magnetization in the paramagnetic regime to a distribution of Langevin functions. The magnetic particle size varies little for Co volume concentrations x 0.32 and increases as the percolation limit is approached. The tunneling magnetoresistance TMR was successfully reproduced using the Inoue-Maekawa model. The maximum value of TMR was temperatureindependent within 50–300 K, and largely increased at low T, suggesting the occurrence of higher-order tunneling processes. Consequently, the tunneling conductance and TMR in clean granular metals are dominated by the Coulomb gap and the inherent particle size distribution

Wachstumskinetik von Si auf Ge(100): Pyramiden und wie man sie vermeidet

Wir haben mittels STM das Wachstum von Si auf Ge(100) zwischen 300 und 600K untersucht. Für Bedeckungen unter 1ML wird zweidimensionales Wachstum beobachtet, was jedoch bei höheren Bedeckungen in dreidimensionales Wachstm übergeht. Dies wird auf eine verschwindende Stufenbarriere an Einfachstufen in Kombination mit einer signifikanten Stufenbarriere an Doppelstufen zurückgeführt. Durch Variation der Depositionsparameter während des Wachstums einer jeden Lage kann die Formation von Doppelstufen in dicken Filmen unterdrückt werden und flache Filme bei niedrigen Temperaturen hergestellt werden. Das entwickelte Verfahren eignet sich auch für die Herstellung von Ge/Si Übergittern bei niedrigen Temperaturen, sodass Interdiffusion der beiden Materialien gegenüber Wachstum bei hohen Temperaturen vermindert werden kann

Competing tunneling and capacitive paths in Co-ZrO2 granular thin films

The ac electrical response is studied in thin films composed of well-defined nanometric Co particles embedded in an insulating ZrO2 matrix which tends to coat them, preventing the formation of aggregates. In the dielectric regime, ac transport originates from the competition between interparticle capacitive Cp and tunneling Rt channels, the latter being thermally assisted. This competition yields an absorption phenomenon at a characteristic frequency 1/(RtCp), which is observed in the range 1010 000 Hz. In this way, the effective ac properties mimic the universal response of disordered dielectric materials. Temperature and frequency determine the complexity and nature of the ac electrical paths, which have been successfully modeled by an Rt-Cp network

The electronic, personalizable Rosetta system for dementia care: exploring the user-friendliness, usefulness and impact

Purpose: This research aimed to integrate three previously developed assistive technology (AT) systems into one modular, multifunctional system, which can support people with dementia and carers throughout the course of dementia. In an explorative evaluation study, the integrated system, called Rosetta, was tested on usefulness, user-friendliness and impact, in people with dementia, their informal carers and professional carers involved. The Rosetta system was installed in participants homes in three countries: The Netherlands, Germany and Belgium. Methods: Controlled trial with pre- and post-test measures across three countries (randomized controlled trial in Germany; matched groups in the Netherlands and Belgium). Participants completed questionnaires for impact measurement and participated in semi-structured interviews regarding usefulness and user-friendliness of Rosetta. Results: All participants agreed that Rosetta is a very useful development. They did not rate the user-friendliness of the system highly. No significant effects were found on impact measurements. Conclusion: All participants found Rosetta a very useful development for future care, and would consider using it. Since Rosetta was still in development during evaluation, a discrepancy between expectations and actual functioning of Rosetta existed, which may explain the lack of findings on the impact of the system and the low appreciation of user-friendliness.Implications for RehabilitationPeople with dementia and carers find assistive technology (AT) a useful future development and they are willing to use it in the future.People with dementia and carers have little privacy issues with AT. If they have concerns, they are willing to accept the trade-off of reduced privacy in exchange for the ability to live in their own homes for longer.Given that a system works flawlessly, informal carers indicate that integrated AT can reduce their burden and stress. This can in turn help informal carers to provide better care for a longer period of time. © 2014 Informa UK Ltd