2,826 research outputs found
Transport and recombination through weakly coupled localized spin pairs in semiconductors during coherent spin excitation
Semi-analytical predictions for the transients of spin-dependent transport
and recombination rates through localized states in semiconductors during
coherent electron spin excitation are made for the case of weakly spin-coupled
charge carrier ensembles. The results show that the on-resonant Rabi frequency
of electrically or optically detected spin-oscillation doubles abruptly as the
strength of the resonant microwave field gamma B_1 exceeds the Larmor frequency
separation within the pair of charge carrier states between which the transport
or recombination transition takes place. For the case of a Larmor frequency
separation of the order of gamma B_1 and arbitrary excitation frequencies, the
charge carrier pairs exhibit four different nutation frequencies. From the
calculations, a simple set of equations for the prediction of these frequencies
is derived
Physical mechanisms involved in grooved flat heat pipes: experimental and numerical analyses
International audienceAn experimental database, obtained with flat plate heat pipes (FPHP) with longitudinal grooves is presented. The capillary pressure measured by confocal microscopy and the temperature field in the wall are presented in various experimental conditions (vapour space thickness, filing ratio, heat transfer rate, tilt angle, fluid). Coupled hydrodynamic and thermal models are developed. Experimental results are compared to results of numerical models. Physical mechanisms involved in grooved heat pipes are discussed, including the boiling limit and the effect of the interfacial shear stress. Finally, recommendations for future experimental and theoretical research to increase the knowledge on FPHP are discussed
Efficacy of different doses and time intervals of oral vitamin D supplementation with or without calcium in elderly nursing home residents: reply to comment by Vieth
Kennisagenda Geo-informatie: GISsen met beleid
LNV wil méér geo-informatie inzetten bij de ontwikkeling en uitvoering van beleid en beleidsnota’s ruimer voorzien van kaartmateriaal. Dit betekent dat geo-informatie vaker moet worden benut om lokale knelpunten, mogelijkheden en de gevolgen van alternatieve oplossingen inzichtelijk te maken. Om dit te bereiken moet de beschikbaarheid van adequate data en gebruikersvriendelijke en nieuwe GIS-technieken aanmerkelijk verbeteren
Investigations on nucleophilic layers made with a novel plasma jet technique
In this work a novel plasma jet technique is used for the deposition of nucleophilic films based on (3-aminopropyl)trimethoxysilane at atmospheric pressure. Film deposition was varied with regard to duty cycles and working distance. Spectral ellipsometry and chemical derivatization with 4-(trifluoromethyl)benzaldehyde using ATR- FTIR spectroscopy measurements were used to characterize the films. It was found that the layer thickness and the film composition are mainly influenced by the duty cycle
Transforming maternity care:obstetric partnerships as a policy instrument for integration
Increasing continuity in Dutch maternity care is considered pivotal to improve safety and client-centeredness. Closer collaboration between the historically relatively autonomous professionals and organizations in maternity care is deemed conditional to reach this goal, both by maternity care professionals and policy makers. Governmental policy therefore strives for organizational and financial integration. One of the policy measures has been to stimulate interprofessional and interorganizational collaboration through local obstetric partnerships. This study aimed to gain insight into whether this policy measure supported professionals in reaching the policy aim of increasing integration in the maternity care system. We therefore conducted 73 semistructured interviews with maternity care professionals in the region Northwest Netherlands, from 2014 to 2016. Respondents expressed much willingness to intensify interprofessional and interorganizational collaboration and experienced obstetric partnerships as contributing to this. As such, stimulating integration through obstetric partnerships can be considered a suitable policy measure. However, collaborating within the partnerships simultaneously highlighted deep-rooted dividing structures (organizational, educational, legal, financial) in the maternity care system, especially at the systemic level. These were experienced to hinder collaboration, but difficult for the professionals to influence, as they lacked knowledge, skills, resources and mandate. A lack of clear and timely guidance and support from policy, counterbalancing these barriers, limited partnerships' potential to unify professionals and integrate their services. (C) 2020 Elsevier B.V. All rights reserved
Large Interstellar Polarisation Survey. LIPS I: FORS2 spectropolarimetry in the Southern Hemisphere
Polarimetric studies of light transmitted through interstellar clouds may
give constraints on the properties of the interstellar dust grains.
Traditionally, broadband linear polarisation (BBLP) measurements have been
considered an important diagnostic tool for the study of the interstellar dust,
while comparatively less attention has been paid to spectropolarimetric
measurements. However, spectropolarimetry may offer stronger constraints than
BBLP, for example by revealing narrowband features, and by allowing us to
distinguish the contribution of dust from the contribution of interstellar gas.
Therefore, we have decided to carry out a Large Interstellar Polarisation
Survey (LIPS) using spectropolarimetric facilities in both hemispheres. Here we
present the results obtained in the Southern Hemisphere with the FORS2
instrument of the ESO Very Large Telescope. Our spectra cover the wavelength
range 380--950\,nm at a spectral resolving power of about 880. We have produced
a publicly available catalogue of 127 linear polarisation spectra of 101
targets. We also provide the Serkowski-curve parameters, as well as the
wavelength gradient of the polarisation position angle for the interstellar
polarisation along 76 different lines of sight. In agreement with previous
literature, we found that the best-fit parameters of the Serkowski-curve are
not independent of each other. However, the relationships that we obtained are
not always consistent with what was found in previous studies.Comment: Accepted by A&A (replaced on 12 October 2017 simply to correct a
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