pinecone/core-2020-05-10-deduplication huggingface dataset:
Surface excitonic emission and quenching effects in ZnO nanowire/nanowall systems: limiting effects on device potential.

We report ZnO nanowire/nanowall growth using a two-step vapour phase transport method on a-plane sapphire. X-ray diffraction and scanning electron microscopy data establish that the nanostructures are vertically well-aligned with c-axis normal to the substrate, and have a very low rocking curve width. Photoluminescence data at low temperatures demonstrate the exceptionally high optical quality of these structures, with intense emission and narrow bound exciton linewidths. We observe a high energy excitonic emission at low temperatures close to the band-edge which we assign to the surface exciton in ZnO at ~ 3.366 eV, the first time this feature has been reported in ZnO nanorod systems. This assignment is consistent with the large surface to volume ratio of the nanowire systems and indicates that this large ratio has a significant effect on the luminescence even at low temperatures. The band-edge intensity decays rapidly with increasing temperature compared to bulk single crystal material, indicating a strong temperature-activated non-radiative mechanism peculiar to the nanostructures. No evidence is seen of the free exciton emission due to exciton delocalisation in the nanostructures with increased temperature, unlike the behaviour in bulk material. The use of such nanostructures in room temperature optoelectronic devices appears to be dependent on the control or elimination of such surface effects
3p photoabsorption spectra of Mn2+ and Mn3+

Time resolved EUV photoabsorption spectra of a manganese plasma have been recorded using the dual laser plasma technique. The 43 - 73 eV photon energy range is dominated by the 3p-3d giant resonance and to a lesser extent the 3p-4s resonances in both Mn2+ and Mn3+, recorded at an interplasma time delay of 80 ns and 30 ns respectively. These experimentally observed resonances are well reproduced by synthetic spectra calculated using the Hartree-Fock method. The synthetic spectra allow for absorption from excited states of the Mn2+ and Mn3+ ions
Constructing a SenseCam visual diary as a media process

The SenseCam is a small wearable personal device which automatically captures up to 2,500 images per day. This yields a very large personal collection of images, or in a sense a large visual diary of a person’s day. Intelligent techniques are necessary for effective structuring, searching and browsing of this image collection for locating\ud
important or significant events in a person’s life. In this paper we identify three stages in the process of capturing and structuring SenseCam images and then displaying them to an end user to review. These stages are expressed in terms of the canonical process stages to which they correlate
Trends in 4d-subshell photoabsorption along the iodine isonuclear sequence: I, I⁺, and I²⁺

The 4d absorption spectra of I, I+, and I2+ have been observed in the 45–300-eV region using the dual laser-produced plasma technique. At lower energies each spectrum is dominated by intense 4d→5p transitions, which are identified with the aid of multiconfiguration Hartree-Fock calculations. The excited states decay by direct autoionization involving 5s or 5p electrons and rates for the different processes and resulting linewidths were calculated and compared, where possible, with experiment. In the case of neutral iodine 4d→6p transitions are also observed in the region close to the 2D5/2 threshold. The dominant feature in each spectrum, however, arises from 4d-f excitation, which evolves from a 4d-ɛf shape resonance in neutral iodine to a feature containing discrete 4d→nf transitions in I2+
Crush analysis and multi-objective optimization design for circular tube under quasi-static lateral loading

This paper addresses the energy absorption behaviour and crashworthiness optimisation of short length circular tubes under quasi-static lateral loading. Finite element (FE) models were developed using implicit FE code ANSYS to simulate the deformation behaviour and energy absorption of circular tube under lateral loading. These FE models were validated using experimental techniques to ensure that they can predict the responses of circular tube with sufficient accuracy. Response Surface Methodology (RSM) for design of experiments (DOE) was used in conjunction with finite element modelling to evaluate systematically the effects of geometrical parameters on the energy absorption responses of laterally crushed circular tubes. Statistical software package, Design-Expert, was used to apply the response surface methodology (RSM). The energy absorbing responses (specific energy absorbing capacity (SEA) and collapse load (F)) were modelled as functions of geometrical factors (tube diameter, tube thickness, and tube width). These developed functions allow predictions of the energy absorption response of laterally crushed tubes, based on their geometry parameters. Based on DOE results, parametric studies were conducted to generate design information on using the laterally crushed tubes in energy absorbing systems. Finally, the approach of multi-objective optimization\ud
design (MOD) was employed to find the optimal configuration of the proposed energy absorption structures. Design-Expert software, which employs the desirability approach as optimization algorithm, was used for solving the MOD problem
Integrating global mobility and global talent management: Exploring the challenges and strategic opportunities

Although global mobility represents an important element of many multinational enterprise's (MNEs) global talent management systems, the two areas of practice have largely been decoupled in research and practice. The current paper aims to build a dialog around the integration of these two important areas of practice and illustrate how the integration of global mobility and global talent management can contribute to the success of the MNE. Human capital and social capital theories are introduced as theoretical frames for the integration of the two areas and global talent pools and routines for managing global staffing flows are introduced as key organizational routines that can maximize the contribution of global mobility to the MNE. The paper also considers challenges and opportunities for the integration of mobility and talent and outlines some directions for future study
Photonics in photovoltaic systems

This paper gives an overview on photonics for photovoltaic systems. Starting from the spectral and angular distribution of the electromagnetic radiation from the sun, many important optical approaches how to improve the efficiency of solar cells are presented and discussed. Topics include antireflective coatings, various light trapping structures, refractive, reflective and fluorescent concentrators, and components for spectral management. The theoretical background is shortly described and examples of the experimental and also of the commercial realisation are given
High quality InAlN single layers lattice-matched to GaN grown by molecular beam epitaxy

We report on properties of high quality ~60 nm thick InAlN layers nearly in-plane lattice-matched to GaN, grown on c-plane GaN-on-sapphire templates by plasma-assisted molecular beam epitaxy. Excellent crystalline quality and low surface roughness are confirmed by X-ray diffraction, transmission electron microscopy, and atomic force microscopy. High annular dark field observations reveal a periodic in-plane indium content variation (8 nm period), whereas optical measurements evidence certain residual absorption below the band-gap. The indium fluctuation is estimated to be +/- 1.2% around the nominal 17% indium content via plasmon energy oscillations assessed by electron energy loss spectroscopy with sub-nanometric spatial resolution
A proposal for multi-tens of GW fully coherent femtosecond soft X-ray lasers

X-ray free-electron lasers1,2 delivering up to 131013 coherent photons in femtosecond pulses are bringing about a revolution in X-ray science3?5. However, some plasma-based soft X-ray lasers6 are attractive because they spontaneously emit an even higher number of photons (131015), but these are emitted in incoherent and long (hundreds of picoseconds) pulses7 as a consequence of the amplification of stochastic incoherent self-emission. Previous experimental attempts to seed such amplifiers with coherent femtosecond soft X-rays resulted in as yet unexplained weak amplification of the seed and strong amplification of incoherent spontaneous emission8. Using a time-dependent Maxwell?Bloch model describing the amplification of both coherent and incoherent soft X-rays in plasma, we explain the observed inefficiency and propose a new amplification scheme based on the seeding of stretched high harmonics using a transposition of chirped pulse amplification to soft X-rays. This scheme is able to deliver 531014 fully coherent soft X-ray photons in 200 fs pulses and with a peak power of 20 GW
Analysis of irregular behaviour on an optical computing logic cell

A new methodology to study irregular behaviours in logic cells is reported. It is based on two types of diagrams, namely phase and working diagrams. Sets of four bits are grouped and represented by their hexadecimal equivalent. Some hexadecimal numbers correspond to certain logic functions. The influence of the internal and external tolerances, namely those appearing in the employed devices and in the working signals, may be analysed with this method. Its importance in the case of logic structures with chaotic behaviours is studied
Performance analysis of a 7-kW crystalline silicon generator after 17 years of operation in Madrid

The degradation observed on a 7-kWp Si-x photovoltaic array after 17 years of exposure on the roof of the Solar Energy Institute of the Polytechnic University of Madrid is presented. The mean peak power degradation has been 9% over this time, or an equivalent to 0.53% per year, whereas peak power standard deviation has remained constant. The main visual defects are backsheet delamination at the polyester/polyvinyl fluoride outer interface and cracks in the terminal boxes and at the joint between the frame and the laminate. Insulation resistance complies well with the requirements of the International Electrotechnical Commission 61215 tests
Hybrid analysis of nonlinear circuits: DAE models with indices zero and one

We extend in this paper some previous results concerning the differential-algebraic index of hybrid models of electrical and electronic circuits. Specifically, we present a comprehensive index characterization which holds without passivity requirements, in contrast to previous approaches, and which applies to nonlinear circuits composed of uncoupled, one-port devices. The index conditions, which are stated in terms of the forest structure of certain digraph minors, do not depend on the specific tree chosen in the formulation of the hybrid equations. Additionally, we show how to include memristors in hybrid circuit models; in this direction, we extend the index analysis to circuits including active memristors, which have been recently used in the design of nonlinear oscillators and chaotic circuits. We also discuss the extension of these results to circuits with controlled sources, making our framework of interest in the analysis of circuits with transistors, amplifiers, and other multiterminal devices
Some aspects of lubrication in heavy regimes: thermal effects, stability and turbulence

In this work, a combination of numerical methods applied to thermohydrodynamic lubrication problems with cavitation is presented. It should be emphasized the difficulty of the nonlinear mathematical coupled model involving a free boundary problem, but also the simplicity of the algorithms employed to solve it. So, finite element discretizations for the hydrodynamic and thermal equations combined with upwind techniques for the convection terms and duality methods for nonlinear features are proposed. Additionally, a model describing the movement of the shaft is provided. Considering the shaft as a rigid body this model will consist of an ODE system relating acceleration of the center of gravity and external and pressure loads. The numerical experiments of mechanical stability try to clarify the position of the neutral stability curve. Finally, a rotating machine for ship propulsion involving both axial and radial bearings operating with nonconventional lubricants (seawater to avoid environmental pollution) is analyzed by using laminar and turbulent inertial flows
Magnetic disorder in TbAl2 nanoparticles

The magnetic and thermal properties of TbAl2 nanosized alloys (diameters, 12 nm $\leqslant D\leqslant $ 20 nm) obtained by high-energy milling are characterised by specific heat, magnetisation and neutron scattering. The specific heat shows that the λ-anomaly at Curie temperature vanishes when the milling time reaches 300 h and its field variation shows a broad peak around 70 K disclosing a disordered magnetic state. The thermal variation of magnetization follows a Bloch process with a decrease of the stiffness constant and a faster demagnetisation with a quadratic exponent instead of the bulk ordinary ${T}^{3/2}$-dependence. The magnetic moment reduction in the nanosized alloys follows a 1/D dependence, remarking the role of disordered moment surface. The Rietveld analysis of the neutron diffraction patterns indicates a collinear ferromagnetic structure, with a reduction of the Tb-magnetic moment when decreasing the particle size. The temperature dependent overall magnetic signal of nanoparticles is derived from small-angle neutron scattering. A magnetic nanoparticle structure with an ordered ferromagnetic core and a disordered surface layer is proposed
Extraction of arabinoxylans from wheat bran using hydrothermal processes assisted by heterogeneous catalysts

The extraction/hydrolysis process of arabinoxylans from destarched wheat bran was studied in this work using different mesoporous silica supports and the corresponding RuCl3-based catalysts. The effects of temperature, time, catalyst supports and ruthenium catalysts were investigated and discussed in terms of the arabinoxylans extraction yield and their polymerization degree. Relatively high temperatures (180 °C), short extraction times (10 min) and RuCl3 supported on Al-MCM-48 led to a high amount of extracted arabinoxylans (78%) with a low molecular weight (9 kDa). Finally, a relation between the operating conditions, the arabinoxylans extraction yield and the molecular weight was stablished based on the obtained results.CTQ2015-64892-R (MINECO/FEDER
Performance of VAMOS for reactions near the Coulomb barrier

Détecteur VAMOSVAMOS (VAriable MOde Spectrometer) is a large solid angle ray-tracing spectrometer employing numerical methods for reconstructing the particle trajectory. Complete identification of reaction products has been achieved by trajectory reconstruction. Equipped with a versatile detection system, VAMOS is capable of identifying reaction products from diverse reactions using beams at GANIL. The technique for trajectory reconstruction and its application for identifying reaction products are presented. The angular acceptance of the spectrometer has been studied using Monte Carlo simulation by an ion optics code. The spectrometer was coupled to the high efficiency EXOGAM γ-array to obtain γ-recoil coincidences for studying nuclei far from stability. The main features of the spectrometer as well as some results applied to experiments in deep inelastic collisions are described
CKM Fits : What the Data Say (Focused on B Physics)

A paraître dans Nuclear Physics B Proceedings SupplementsInternational audienceAn up-to-date profile of the Cabibbo-Kobayashi-Maskawa matrix is given with emphasis on the interpretation of recent results on CP violation from the B factories. We provide a review of the relevant experimental and theoretical inputs from the contributing domains of the electroweak interaction. We give numerical and graphical constraints on the CKM parameters and predictions of related physical observables. We discuss the impact of what the data actually say on model-independent studies of new physic
TuCCompi: a multi-layer model for distributed heterogeneous computing with tuning capabilities

Producción CientíficaDuring the last decade, parallel processing architectures have become a powerful tool to deal with massively-parallel problems that require High Performance Computing (HPC). The last trend of HPC is the use of heterogeneous environments, that combine different computational processing devices, such as CPU-cores and GPUs (Graphics Processing Units). Maximizing the performance of any GPU parallel implementation of an algorithm requires an in-depth knowledge about the GPU underlying architecture, becoming a tedious manual effort only suited for experienced programmers. In this paper, we present TuCCompi, a multi-layer abstract model that simplifies the programming on heterogeneous systems including hardware accelerators, by hiding the details of synchronization, deployment, and tuning. TuCCompi chooses optimal values for their configuration parameters using a kernel characterization provided by the programmer. This model is very useful to tackle problems characterized by independent, high computational-load independent tasks, such as embarrassingly-parallel problems. We have evaluated TuCCompi in different, real-world, heterogeneous environments using the All-Pair Shortest-Path problem as a case study.Ministerio de Economía y Competitividad and ERDF program of the European Union: CAPAP-H5 network (TIN2014-53522-REDT), MOGECOPP project (TIN2011-25639); Junta de Castilla y Leon (Spain): ATLAS project (VA172A12-2); and the COST Program Action IC1305: NESUS
Type N universal spacetimes

This work is published under licence by IOP Publishing Ltd. It may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. 10.1088/1742-6596/600/1/012065Universal spacetimes are vacuum solutions to all theories of gravity with the
Lagrangian L [...]. Well known examples of universal
spacetimes are plane waves which are of the Weyl type N. Here, we discuss recent results on
necessary and sufficient conditions for all Weyl type N spacetimes in arbitrary dimension and we
conclude that a type N spacetime is universal if and only if it is an Einstein Kundt spacetime.
We also summarize the main points of the proof of this result
Photoconductivity and characterization of nitrogen incorporated hydrogenated amorphous carbon thin films

The observation and origin of photoconductivity in high base pressure (∼10−3 Torr) grown nitrogen incorporated hydrogenated amorphous carbon (a-C:H:N) thin films is reported. The magnitude of conductivity at room temperature was measured to increase by nearly two orders of magnitude and exhibits a maximum ratio of photoconductivity to dark conductivity of 1.5 as the nitrogen content increased to 15.1 at. %. X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and Fourier transform infrared spectroscopy reveal enhanced sp2 bonding at higher nitrogen contents. Residual film stress, Tauc band gap, hardness, and elastic modulus are all found to decrease with addition of nitrogen. The electrical characteristics suggest the creation of a-C:H:N/p-Si heterojunction diodes having rectifying behavior. The conductivity and electrical characteristics are discussed in term of band model, and the results show that high quality a-C:H:N films can be grown at high base pressures with properties comparable to those grown at low base pressures
Collective electronic excitations in metal-coated C_60

Producción CientíficaA two-shell jellium-on-jellium model has been used to study the collective electronic excitations of C_60 coated by an increasing number N of Na atoms. We predict a transition from the π-electron polarization of the fullerene to the metallic sodium polarization as a function of increasing N. For low coverages, the Na layer produces only a broadening and fragmentation of the π plasmon of C_60. However, if the coverage is large enough, a Na surface plasmon appears. This occurs only after the electron density of the cluster clearly shows two distinct regions, the outer one having an ‘‘average’’ density similar to that in pure Na metal or Na clusters. The induced density at the collective-mode frequency shows structure corresponding to two interfaces, C_(60-)Na and Na vacuum, the first peak becoming less pronounced as the coverage increases due to a transfer of oscillator strength to the metallic counterpart. The static polarizability per electron also shows this trend and tends slowly to the Na value from below after an initial sharp rise in the region N∼13–21
Evidence for population sub-structuring in São Tomé e Príncipe as inferred from Y-chromosome STR analysis

Seven Y-chromosome STR loci, DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392 and DYS393 have been analysed in population samples of Angolares, Forros and Tongas, three ethnic groups from the African archipelago of São Tomé e Príncipe (Gulf of Guinea). Complete typings were obtained for 103 chromosomes, which belonged to 79 different haplotypes. The mean heterozygosity per locus in the overall São Tomean sample was 0.566, with the highest value found among Forros and the lowest among Angolares. Angolares also showed the lowest level of haplotype diversity. On average, the mean pairwise difference between two random haplotypes from Angolares, Forros and Tongas was 4.69, 6.74 and 6.23 repeats, respectively. The genetic distances were found to be statistically significant between Angolares and Forros or Tongas. In accordance, AMOVA revealed that the percentage of variation attributable to differences among groups was only significant when we distinguished between Angolares and non-Angolares. Globally, these results indicate that, with respect to the pool of male lineages of São Tomé e Príncipe, some genetic sub-structuring does exist, basically determined by the Angolares ethnic group.http://dx.doi.org/10.1046/j.1469-1809.2001.6530271.
Influence of vanadate on glycolysis, intracellular sodium, and pH in perfused rat hearts

Vanadium compounds have been shown to cause a variety of biological and metabolic effects including inhibition of certain enzymes, alteration of contractile function, and as an insulin like regulator of glucose metabolism. However, the influence of vanadium on metabolic and ionic changes in hearts remains to be understood. In this study we have examined the influence of vanadate on glucose metabolism and sodium transport in isolated perfused rat hearts. Hearts were perfused with 10 mM glucose and varying vanadate concentrations (0.7-100 µM) while changes in high energy phosphates (ATP and phosphocreatine (PCr)), intracellular pH, and intracellular sodium were monitored using 31P and 23Na NMR spectroscopy. Tissue lactate, glycogen, and (Na+, K+)-ATPase activity were also measured using biochemical assays. Under baseline conditions, vanadate increased tissue glycogen levels two fold and reduced (Na+, K+)-ATPase activity. Significant decreases in ATP and PCr were observed in the presence of vanadate, with little change in intracellular pH. These changes under baseline conditions were less severe when the hearts were perfused with glucose, palmitate and b-hydroxybutyrate. During ischemia vanadate did not limit the rise in intracellular sodium, but slowed sodium recovery on reperfusion. The presence of vanadate during ischemia resulted in attenuation of acidosis, and reduced lactate accumulation. Reperfusion in the presence of vanadate resulted in a slower ATP recovery, while intracellular pH and PCr recovery was not affected. These results indicate that vanadate alters glucose utilization and (Na+, K+)-ATPase activity and thereby influences the response of the myocardium to an ischemic insult.http://dx.doi.org/10.1023/A:100689993210