211 research outputs found
Comparison between the Efficiency of Heterojunction Thin Film InGaP\GaAs\Ge and InGaP\GaAs Solar Cell
This paper presents the design parameters for a thin film 3J InGaP/GaAs/Ge solar cell with a simulated maximum efficiency of 32.11% using Tcad Silvaco. Design parameters include the doping concentration, molar fraction, layers’ thickness and tunnel junction characteristics. An initial dual junction InGaP/GaAs model of a previous published heterojunction cell was simulated in Tcad Silvaco to accurately predict solar cell performance. To improve the solar cell’s performance, we have fixed meshing, material properties, models and numerical methods. However, thickness and layer doping concentration were taken as variables. We, first simulate the InGaP\GaAs dual junction cell by changing the doping concentrations and thicknesses which showed an increase in efficiency. Next, a triple junction InGaP/GaAs/Ge cell was modeled by adding a Ge layer to the previous dual junction InGaP/GaAs model with an InGaP /GaAs tunnel junction
Two types of all-optical magnetization switching mechanisms using femtosecond laser pulses
Magnetization manipulation in the absence of an external magnetic field is a
topic of great interest, since many novel physical phenomena need to be
understood and promising new applications can be imagined. Cutting-edge
experiments have shown the capability to switch the magnetization of magnetic
thin films using ultrashort polarized laser pulses. In 2007, it was first
observed that the magnetization switching for GdFeCo alloy thin films was
helicity-dependent and later helicity-independent switching was also
demonstrated on the same material. Recently, all-optical switching has also
been discovered for a much larger variety of magnetic materials (ferrimagnetic,
ferromagnetic films and granular nanostructures), where the theoretical models
explaining the switching in GdFeCo films do not appear to apply, thus
questioning the uniqueness of the microscopic origin of all-optical switching.
Here, we show that two different all-optical switching mechanisms can be
distinguished; a "single pulse" switching and a "cumulative" switching process
whose rich microscopic origin is discussed. We demonstrate that the latter is a
two-step mechanism; a heat-driven demagnetization followed by a
helicity-dependent remagnetization. This is achieved by an all-electrical and
time-dependent investigation of the all-optical switching in ferrimagnetic and
ferromagnetic Hall crosses via the anomalous Hall effect, enabling to probe the
all-optical switching on different timescales.Comment: 1 page, LaTeX; classified reference number
Polarimetry of 16Ngs produced in mu --capture on 16O nuclei
A polarimetry technique based on stack targets and /3-'/-coincidences
has been applied to the 16N nuclei produced in the ground state capture
of negative muons on lb0 nuclei. The performance of the polarimeter and
the first measurements of /3-asymmetry due to the longitudinal nuclear
polarization are discussed
Magnetisation switching of FePt nanoparticle recording medium by femtosecond laser pulses
Manipulation of magnetisation with ultrashort laser pulses is promising for information storage device applications. The dynamics of the magnetisation response depends on the energy transfer from the photons to the spins during the initial laser excitation. A material of special interest for magnetic storage are FePt nanoparticles, for which switching of the magnetisation with optical angular momentum was demonstrated recently. The mechanism remained unclear. Here we investigate experimentally and theoretically the all-optical switching of FePt nanoparticles. We show that the magnetisation switching is a stochastic process. We develop a complete multiscale model which allows us to optimize the number of laser shots needed to switch the magnetisation of high anisotropy FePt nanoparticles in our experiments. We conclude that only angular momentum induced optically by the inverse Faraday effect will provide switching with one single femtosecond laser pulse.EC under Contract No. 281043, FemtoSpin. The work at Greifswald University
was supported by the German research foundation (DFG), projects MU MU 1780/8-1, MU 1780/10-1. Research
at Göttingen University was supported via SFB 1073, Projects A2 and B1. Research at Uppsala University was
supported by the Swedish Research Council (VR), the Röntgen-Ångström Cluster, the Knut and Alice Wallenberg
Foundation (Contract No. 2015.0060), and Swedish National Infrastructure for Computing (SNIC). Research at
Kiel University was supported by the DFG, projects MC 9/9-2, MC 9/10-2. P.N. acknowledges support from EU
Horizon 2020 Framework Programme for Research and Innovation (2014-2020) under Grant Agreement No.
686056, NOVAMAG. The work in Konstanz was supported via the Center for Applied Photonics
The synthetic antimicrobial peptide 19-2.5 attenuates septic cardiomyopathy and prevents down-regulation of SERCA2 in polymicrobial sepsis
LM has received grants by the Faculty of Medicine at the RWTH Aachen University (START 15/14 and
START 46/16) and the Deutsche Forschungsgemeinschaft (DFG, MA 7082/1–1). This work was supported by
the Immunohistochemistry and Confocal Microscopy Unit, a core facility of the Interdisciplinary Centre for
Clinical Research (IZKF) Aachen, within the Faculty of Medicine at the RWTH Aachen University and the
RWTH centralized Biomaterial Database (RWTH cBMB) of the University Hospital RWTH Aachen. We are
very grateful to Antons Martincuks M.Sc. and Professor Gerhard Müller-Newen for live-cell imaging. This work
was supported, in part, by the University of Turin (ex-60% 2015A and B) and by the William Harvey Research
Foundation and forms part of the research themes contributing to the translational research portfolio of Barts
and the London Cardiovascular Biomedical Research Unit that is supported and funded by the National Institute
for Health Research. This work also contributes to the Organ Protection research theme of the Barts Centre for
Trauma Sciences supported by the Barts and The London Charity (Award 753/1722)
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