1,297 research outputs found
Spin thermoelectrics in a disordered Fermi gas
We study the connection between the spin-heat and spin-charge response in a
disordered Fermi gas with spin-orbit coupling. It is shown that the ratio
between the above responses can be expressed as the thermopower times a number which depends on the strength and
type of the spin-orbit couplings considered. The general results are
illustrated by examining different two-dimensional electron or hole systems
with different and competing spin-orbit mechanisms, and we conclude that a
metallic system could prove much more efficient as a heat-to-spin than as a
heat-to-charge converter.Comment: 6 pages, 1 figur
Spin Hall and Edelstein effects in metallic films: from 2D to 3D
A normal metallic film sandwiched between two insulators may have strong
spin-orbit coupling near the metal-insulator interfaces, even if spin-orbit
coupling is negligible in the bulk of the film. In this paper we study two
technologically important and deeply interconnected effects that arise from
interfacial spin-orbit coupling in metallic films. The first is the spin Hall
effect, whereby a charge current in the plane of the film is partially
converted into an orthogonal spin current in the same plane. The second is the
Edelstein effect, in which a charge current produces an in-plane, transverse
spin polarization. At variance with strictly two-dimensional Rashba systems, we
find that the spin Hall conductivity has a finite value even if spin-orbit
interaction with impurities is neglected and "vertex corrections" are properly
taken into account. Even more remarkably, such finite value becomes "universal"
in a certain configuration. This is a direct consequence of the spatial
dependence of spin-orbit coupling on the third dimension, perpendicular to the
film plane. The non-vanishing spin Hall conductivity has a profound influence
on the Edelstein effect, which we show to consist of two terms, the first with
the standard form valid in a strictly two-dimensional Rashba system, and a
second arising from the presence of the third dimension. Whereas the standard
term is proportional to the momentum relaxation time, the new one scales with
the spin relaxation time. Our results, although derived in a specific model,
should be valid rather generally, whenever a spatially dependent Rashba
spin-orbit coupling is present and the electron motion is not strictly
two-dimensional.Comment: 23 pages, 3 figure
Descritpion of Exotic Nuclei Using Continuum Shell Model
In weakly bound exotic nuclei, number of excited bound states or narrow
resonances is small and, moreover, they couple strongly to the particle
continuum. Hence, these systems should be described in the quantum open system
formalism which does not artificially separate the subspaces of (quasi-) bound
and scattering states. The Shell Model Embedded in the Continuum provides a
novel approach which solves this problem. Examples of application in sd-shell
nuclei will be presented.Comment: Presented at the NATO Advanced Research Workshop Brijuni, Pula,
Croatia, June 2-5, 200
Levels, sources and seasonality of coarse particles (PM10-PM2.5) in three European capitals e implications for particulate pollution control
Coarse particles of aerodynamic diameter between 2.5 and 10 mm (PMc) are produced by a range of natural (windblown dust and sea sprays) and anthropogenic processes (non-exhaust vehicle emissions, industrial, agriculture, construction and quarrying activities). Although current ambient air quality regulations focus on PM2.5 and PM10, coarse particles are of interest from a public health point of view as they have been associated with certain mortality and morbidity outcomes. In this paper, an analysis of coarse particle levels in three European capitals (London, Madrid and Athens) is presented and discussed. For all three cities we analysed data from both traffic and urban background monitoring sites. The results showed that the levels of coarse particles present significant seasonal, weekly and daily variability. Their wind driven and non-wind driven resuspension as well as their roadside increment due to traffic were estimated. Both the local meteorological conditions and the air mass history indicating long-range atmospheric transport of particles of natural origin are significant parameters that influence the levels of coarse particles in the three cities especially during episodic events
FORMULATION AND EVALUATION OF GLICLAZIDE NANOSPONGES
Objective: The objective of the present study was to develop and characterize an optimal stable nanosponges of Gliclazide (GLZ) by using the emulsion solvent diffusion method and aimed to increase its bioavailability and release the drug in sustained and controlled manner.
Methods: The GLZ nanosponge was prepared by emulsion solvent diffusion method using different drug-polymer ratios (1:1 to 1:5) Eudragit S100 is used as a polymer. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) estimated the compatibility of GLZ with polymer. All formulations evaluated for production yield, entrapment efficiency, in vitro drug release, scanning electron microscopy (SEM) and stability studies.
Results: The DSC and FTIR Studies revealed that no interaction between drug and polymer. The Production yield of all batches in the range of 73.8±0.30 to 85.6±0.32. Batch F3 showed the highest production yield, the entrapment efficiency of batch F3 70.6±0.77. The average particle size ranges from 303±2.36 to 680±2.50 nm. By the end of 10th hour F3 formulation shown highest drug release was found to be 94.40±1.12%. The release kinetics of the optimized formulation shows zero-order drug release. The stability study indicates no significant change in the in vitro dissolution profile of optimized formulation.
Conclusion: The results of various evaluation parameters, revealed that GLZ nanosponges would be possible alternative delivery systems to conventional formulation to improve its bioavailability, the emulsion solvent diffusion method is best method for preparation of nanosponges and release the drug in sustained and controlled manner
Study of bound states in 12Be through low-energy 11Be(d,p)-transfer reactions
The bound states of 12Be have been studied through a 11Be(d,p)12Be transfer
reaction experiment in inverse kinematics. A 2.8 MeV/u beam of 11Be was
produced using the REX-ISOLDE facility at CERN. The outgoing protons were
detected with the T-REX silicon detector array. The MINIBALL germanium array
was used to detect gamma rays from the excited states in 12Be. The gamma-ray
detection enabled a clear identification of the four known bound states in
12Be, and each of the states has been studied individually. Differential cross
sections over a large angular range have been extracted. Spectroscopic factors
for each of the states have been determined from DWBA calculations and have
been compared to previous experimental and theoretical results
Visualizing Qualitative Data: Creative Approaches for Analyzing and Demonstrating Lively Data from Diverse Learning Settings
This structured poster session aims to showcase novel approaches of qualitativelyanalyzing and communicating lively data—data that is complex, nuanced, multimodal, and multi-voiced. Such data is rich but also messy, often defying the traditional text-based forms of description and presentation. Therefore, the session pairs creative techniques and methods to analyze, triangulate, and/or visualize qualitative findings across multiple data sources (e.g., video, digital and physical spaces, participant artifacts, and patterns of movement) from diverse learning contexts (e.g., museums, libraries, outdoor spaces, and classrooms)—beyond showing transcriptions. The visual format of the session supports our goal of sharing and communicating rich data stories for further discussion with diverse audiences
Indication of Anisotropy in Electromagnetic Propagation over Cosmological Distances
We report a systematic rotation of the plane of polarization of
electromagnetic radiation propagating over cosmological distances. The effect
is extracted independently from Faraday rotation, and found to be correlated
with the angular positions and distances to the sources. Monte Carlo analysis
yields probabilistic P-values of order 10^(-3) for this to occur as a
fluctuation. A fit yields a birefringence scale of order 10^(25) meters.
Dependence on redshift z rules out a local effect. Barring hidden systematic
bias in the data, the correlation indicates a new cosmological effect.Comment: 5 pages, 1 figure, ReVTeX. For more information, see
http://www.cc.rochester.edu/college/rtc/Borge/aniso.htm
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