2,706 research outputs found
BCS-BEC crossover and effects of density fluctuations in a two-component Fermi gas described by the three-dimensional attractive Hubbard model
Some Cohomotopy Groups of Suspended Projective Planes
In this paper we compute some cohomotopy groups of the
suspended complex and quaternionic projective plane by use of the exact sequence associated with the canonical cofiber sequence and a formula about a multiple of the identity class of the suspended projective plane.</p
Effect of field damping layer on two step absorption of quantum dots solar cells
Multi-stacked InAs/AlGaAs quantum dot solar cells (QDSCs) introduced with field damping layers (FDL) which sustain the junction built-in potential have been studied. Without an external bias condition, the external quantum efficiency (EQE) of QD layers are reduced by introducing the thick FDL, because the carrier escape due to built-in electric field was suppressed. On the other hand, the photocurrent production due to two-step absorption is increased by the formation of flat-band QD structure for QDSC with thick FDL
Vers l'évaluation des données pariétales fluctuantes avec des méthodes de frontières immergées
International audienceImmersed boundary conditions (IBC) has reached a sufficient level of maturity to allow the simulation of compressible high Reynolds number flows around complex geometries. However, the reconstruction of physical quantities at the wall of geometries introduced using IBC is far from being straightforward. The difficulty to obtain a prediction as accurate as for classical body-fitted approaches originates from the intrinsic mismatch between immersed boundaries and the underlying mesh. To tackle this issue, a novel method to compute global loads and to provide precise wall data in the view of spectral analyses is introduced. First, this method is assessed for the investigation of highly unsteady separating compressible flows of two space launcher afterbody configurations using Zonal Detached Eddy Simulation (ZDES). Then, the results are compared against validated numerical simulations using a classical body-fitted approach. Finally, the present method successfully returns wall quantities with IBC consistent with classical methodologies and without additional time-consuming operations.Les méthodes de frontières immergées ont atteint un niveau suffisant de maturité pour permettre la simulation des écoulements compressibles à haut nombre de Reynolds sur des géométries complexes. Cependant la reconstruction des valeurs pariétales introduites pas une approche de frontières immergées est un problème complexe. La principale difficulté provient de la dissociation intrinsèque à la méthode entre le maillage de fond utilisé durant la simulation et l’objet immergé. Afin de résoudre ce problème, une nouvelle méthode a été développée afin de permettre le calcul des efforts aérodynamiques et de permettre l’analyse spectrale des données pariétales sur une paroi modélisée par une approche de frontières immergées. Cette méthode a été appliquée afin de simuler l’écoulement autour de deux arrière-corps de lanceurs spatiaux en utilisant la Zonal Detached Eddy Simulation (ZDES). Les grandeurs pariétales fluctuantes sur les parois modélisées par une approche de frontières immergées ont été comparées à des calculs obtenus par des méthodes classiques. Les résultats ont montré que l’approche proposée permet d’évaluer les grandeurs pariétales modélisées par des approches de frontières immergées
One-neutron knockout reaction of 17C on a hydrogen target at 70 MeV/nucleon
First experimental evidence of the population of the first 2- state in 16C
above the neutron threshold is obtained by neutron knockout from 17C on a
hydrogen target. The invariant mass method combined with in-beam gamma-ray
detection is used to locate the state at 5.45(1) MeV. Comparison of its
populating cross section and parallel momentum distribution with a Glauber
model calculation utilizing the shell-model spectroscopic factor confirms the
core-neutron removal nature of this state. Additionally, a previously known
unbound state at 6.11 MeV and a new state at 6.28(2) MeV are observed. The
position of the first 2- state, which belongs to a member of the lowest-lying
p-sd cross shell transition, is reasonably well described by the shell-model
calculation using the WBT interaction.Comment: 15 pages, 3 figure
Neutron Diffraction Study of Nickel in the Liquid State
The structure of nickel in the liquid state has been studied by neutron diffraction at 1500℃. After calculating the interference function (Fourier analysis), the atomic radial distribution function was evaluated from which interatomic distance and coordination number were obtained
Dominant and novel clades of Candidatus Accumulibacter phosphatis in 18 globally distributed full-scale wastewater treatment plants
Here we employed quantitative real-time PCR (qPCR) assays for polyphosphate kinase 1 (ppk1) and 16S rRNA genes to assess relative abundances of dominant clades of Candidatus Accumulibacter phosphatis (referred to Accumulibacter) in 18 globally distributed full-scale wastewater treatment plants (WWTPs) from six countries. Accumulibacter were not only detected in the 6 WWTPs performing biological phosphorus removal, but also inhabited in the other 11 WWTPs employing conventional activated sludge (AS) with abundances ranging from 0.02% to 7.0%. Among the AS samples, clades IIC and IID were found to be dominant among the five Accumulibacter clades. The relative abundance of each clade in the Accumulibacter lineage significantly correlated (p < 0.05) with the influent total phosphorus and chemical oxygen demand instead of geographical factors (e.g. latitude), which showed that the local wastewater characteristics and WWTPs configurations could be more significant to determine the proliferation of Accumulibacter clades in full-scale WWTPs rather than the geographical location. Moreover, two novel Accumulibacter clades (IIH and II-I) which had not been previously detected were discovered in two EBPR WWTPs. The results deepened our understanding of the Accumulibacter diversity in environmental samples
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