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This article focuses on spallation reactions, i.e. interactions of energetic nucleons, basically with a kinetic energy in the 100MeV to a few GeV range, with a target nucleus. These processes are described rather successfully by the so-called Intranuclear Cascade (INC) plus evaporation models. They can be viewed as a first stage of nucleon-nucleon collisions, ejecting fast particles, followed by evaporation of slow particles from the target remnant. These cascade + evaporation models have, now, globally reached a high level of predictive power, owing in particular to successive research programs. The present work, which is an outcome of one of these programs, the recent European Union ANDES research program, deals with a set of reactions (or observable quantities), which can be due to a single collision, such as the one-nucleon removal reactions or the quasi-elastic elastic process. A survey of the experimental data is presented, which allows to clearly point out that, often, the INC models are unsatisfactory for the description of these peculiar events, whereas they are rather successful for the rest of the experimental data. This paradoxical situation is tentatively related to quasi-particle effects which are neglected in INC models.

Transmission electron microscopy (TEM) has been used to investigate the nanoscale morphology of some contemporary lustre glazes. High-resolution TEM, electron energy-loss spectroscopy and energy-dispersive X-ray analysis data imply that two kinds of nanoparticles are present in the lustre layer, namely metallic Ag and metallic Cu particles. Moreover, these particles appear separated in the material. The dense top layer consists of Ag particles and the particles occurring below this upper layer are metallic Cu. A depth profile of the sizes of the nanoparticles with respect to their penetration depths has been drawn. The particle sizes are mainly situated in the range of 5 nm to 15 nm, though smaller and larger particles occur frequently.

Abstract We report a new H2-He potential energy surface that, with respect to the previous one [Bakr et al.(2013)], covers much larger range of H2 stretching and exhibits more accurate asymptotic behavior for large separations between H2 and He. Close-coupling calculations performed on this improved potential energy surface allow us to provide line shape parameters for H2 between 5 and 2000 K for Raman isotropic Q lines and anisotropic Q lines (or electric quadrupole lines) and for vibrational bands from the ground up to v = 5 and rotational quantum numbers up to j = 5 . The parameters provided include the usual pressure -broadening and -shifting coefficients as well as the real and imaginary part of Dicke contribution to the Hess profile. The latter parameters can be readily implemented in other line-shape profiles like the most recent one of Hartmann and Tran.

Today, wide bandgap (WBG) GaN semiconductors are considered the future, allowing the improvement of power transistors. The main advantage of GaN is the presence of two-dimensional electron gas (2Deg) typically used as a conduction layer in normally-on and normally-off transistors. Concerning the normally-off family, several solutions are proposed. Among these, one of the most promising is the MIS-Gate technology that features a gate recess architecture allowing the semiconductor to physically cut off the 2Deg and drastically decrease gate–source leakage currents. The Vth relaxation characteristic, after voltage stress, has been investigated. It has been shown that the main impact is due to charges close to the gate dielectric/GaN interface, precisely dwelling within the dielectric or the GaN epitaxy. This work provides an analytical model of the Vth evolution of these MIS-GATE (metal insulator semiconductor gate) transistors fabricated on GaN-silicon substrate. This model allows the extraction of different trap energy levels from a temporary threshold voltage (Vth) shift after 650 V stress. Based on this method, it is possible to identify up to four different trap energy levels. By comparing state of the art methods, we show that these obtained energy levels are well correlated with either magnesium and carbon impurity or Ga and/or N vacancy sites in the GaN epitaxy.

AbstractA new strategy for the development of III-V/Si tandem solar cells has recently been proposed consisting in low temperature PECVD epitaxy of silicon or silicon-germanium on gallium-arsenide. This paper thus gives first insights about theoretical but realistic maximum performance of such tandem cells by means of full numerical simulations considering perfect layers and interfaces. The consequences of using a thin epi-Si bottom cell instead of a thick silicon substrate are investigated. In case no light trapping scheme is considered, a minimum epi-layer thickness of 20μm is mandatory for the tandem to exhibit higher conversion efficiencies than a single GaAs solar cell. The epi-Si can yet be advantageously replaced by an epitaxial silicon-germanium alloy to increase the bottom cell optical absorption and thus decrease the minimum required thickness by a factor of ∼4 (∼5μm). Finally, simulations show that over 33% efficiency can be obtained for AlxGa1-xAs/epi-Si0.63Ge0.27, which confirms that this is a promising new concept.

La physique ouverte et cachée des saveurs lourdes dans les collisions nucléaires à haute énergie entre dans une nouvelle étape passionnante vers une compréhension plus claire des nouveaux résultats expérimentaux avec la possibilité de les lier directement à l'avancement de la chromodynamique quantique en treillis (QCD). Des résultats récents d'expériences et de développements théoriques concernant la dynamique des saveurs lourdes ouvertes et cachées ont été débattus lors de l'atelier de Lorentz Tomography of the Quark-Gluon Plasma with Heavy Quarks, qui s'est tenu en octobre 2016 à Leiden, aux Pays-Bas. Dans cette contribution, nous résumons les compréhensions communes identifiées et les stratégies développées pour les cinq prochaines années, qui visent à acquérir une connaissance approfondie des propriétés dynamiques du plasma quark-gluon. La física de sabor intenso abierta y oculta en colisiones nucleares de alta energía está entrando en una nueva y emocionante etapa para alcanzar una comprensión más clara de los nuevos resultados experimentales con la posibilidad de vincularlos directamente con el avance en la cromodinámica cuántica reticular (QCD). Los resultados recientes de experimentos y desarrollos teóricos sobre dinámicas abiertas y ocultas de sabor intenso se han debatido en el Lorentz Workshop Tomography of the Quark-Gluon Plasma with Heavy Quarks, que se celebró en octubre de 2016 en Leiden, Países Bajos. En esta contribución, resumimos los entendimientos comunes identificados y las estrategias desarrolladas para los próximos cinco años, que tienen como objetivo lograr un conocimiento profundo de las propiedades dinámicas del plasma de quarks y gluones. Open and hidden heavy-flavor physics in high-energy nuclear collisions are entering a new and exciting stage towards reaching a clearer understanding of the new experimental results with the possibility to link them directly to the advancement in lattice Quantum Chromo-Dynamics (QCD). Recent results from experiments and theoretical developments regarding open and hidden heavy-flavor dynamics have been debated at the Lorentz Workshop Tomography of the Quark-Gluon Plasma with Heavy Quarks, which was held in October 2016 in Leiden, The Netherlands. In this contribution, we summarize identified common understandings and developed strategies for the upcoming five years, which aim at achieving a profound knowledge of the dynamical properties of the quark-gluon plasma. تدخل فيزياء النكهة الثقيلة المفتوحة والمخفية في التصادمات النووية عالية الطاقة مرحلة جديدة ومثيرة نحو الوصول إلى فهم أوضح للنتائج التجريبية الجديدة مع إمكانية ربطها مباشرة بالتقدم في الديناميكيات الكمومية الشبكية (QCD). تمت مناقشة النتائج الأخيرة من التجارب والتطورات النظرية المتعلقة بديناميكيات النكهة الثقيلة المفتوحة والمخفية في ورشة لورنتز للتصوير المقطعي لبلازما كوارك- غلوون مع الكواركات الثقيلة، والتي عقدت في أكتوبر 2016 في ليدن، هولندا. في هذه المساهمة، نلخص التفاهمات المشتركة المحددة والاستراتيجيات المطورة للسنوات الخمس القادمة، والتي تهدف إلى تحقيق معرفة عميقة بالخصائص الديناميكية لبلازما كوارك- غلوون.