Effects of coupling to breakup in the 6,7 Li + 64 Zn systems at near-barrier energies

Elastic scattering angular distributions for the weakly bound nucleus Li7 on Zn64 have been measured in a wide angular range at energies around the Coulomb barrier. The present experimental data and our previously measured elastic scattering data for the system Li6+Zn64 have been analyzed within the continuum-discretized coupled-channels method, where the resonant and nonresonant states of the projectile are taken into account. In this theoretical framework, we have also analyzed our previously measured excitation functions of elastic scattering at backward angles and the corresponding barrier distributions for the same systems. A good agreement between the experimental data and the calculations has been observed. The obtained results, besides confirming the importance of the coupling to the breakup channels in collisions with weakly bound nuclei, show that, in the case of Li6, the inclusion of the resonant states of the projectile produces non-negligible effects.Ministerio de Economía y Competitividad (España) FIS2013-41994-PJunta de Andalucía FQM160 P07-FQM-02894Programa Consolider-Ingenio 2010 (España) CSD2007-0004

Гибридный движитель

The authors presented a conceptual idea of a high-speed mainline with a maximum speed of 400–450 km/h. The use of rotary engines requires more energy at high speeds, there are difficulties with current collection, wheel-rail adhesion, etc. At the same time, the use of a linear traction motor at low speeds is not justified from an economic point of view, but efficient at high speed in terms of operation. In this regard, an option of a combined or hybrid traction propulsion unit is offered, in which the positive aspects of previous models interfit.Авторами представлена концептуальная идея о высокоскоростной магистрали с максимальной скоростью движения 400–450 км/ч. Использование ротационных двигателей требует больших энергозатрат на высоких скоростях, возникают сложности с токосъёмом, сцеплением колеса с рельсом и т. д. В то же время применение линейного тягового двигателя на низких скоростях не оправдано с экономической точки зрения, но эффективно на высоких с позиции эксплуатации. В связи с этим предлагается вариант совмещенного или гибридного тягового движителя, в котором сопрягаются положительные стороны прежних моделей

Stopping power of helium gas for ^9Be ions from 2 to 31 MeV

Abstract The stopping power of helium gas for 9Be ions from 2 to 31 MeV is experimentally determined using an indirect method. The residual energy of the 9Be beam as a function of the gas thickness is measured and the stopping power determined by differentiating the thickness–energy curve. The results are compared with predictions of the semi-empirical codes SRIM-2003 and MSTAR. Our data are in better agreement with the MSTAR calculations. The elastic scattering excitation function for the system 9Be + α, extracted using the thick target technique and our stopping power data, is in excellent agreement with the ones measured directly confirming the quality of our data

Expanding the palette of phenanthridinium cations

5,6-Disubstituted phenanthridinium cations have a range of redox, fluorescence and biological properties. Some properties rely on phenanthridiniums intercalating into DNA, but the use of these cations as exomarkers for the reactive oxygen species (ROS), superoxide, and as inhibitors of acetylcholine esterase (AChE) do not require intercalation. A versatile modular synthesis of 5,6-disubstituted phenanthridiniums that introduces diversity by Suzuki–Miyaura coupling, imine formation and microwave-assisted cyclisation is presented. Computational modelling at the density functional theory (DFT) level reveals that the novel displacement of the aryl halide by an acyclic N-alkylimine proceeds by an SNAr mechanism rather than electrocyclisation. It is found that the displacement of halide is concerted and there is no stable Meisenheimer intermediate, provided the calculations consistently use a polarisable solvent model and a diffuse basis set

Heavy residue excitation functions for the collisions 6, 7Li + 64Zn near the Coulomb barrier

Excitation functions for the production of heavy residues have been measured for the collisions 6, 7Li+64Zn at energies around and below the Coulomb barrier. The cross sections for heavy residue production have been measured using an activation technique, detecting off-line the characteristic atomic x-rays emitted in the electron capture decay of the reaction products. The experimental relative yields of the residues have been compared with statistical model calculations performed by using the code cascade. Such a comparison suggests that heavy residue production is dominated by complete fusion at above-barrier energies, whereas different processes like incomplete fusion and/or transfer become dominant in the sub-barrier energy region. The heavy residue excitation function ratio between the 6Li- and 7Li-induced collisions shows an increasing trend as the energy decreases below the barrier

Magnetic phases and reorientation transitions in antiferromagnetically coupled multilayers

In antiferromagnetically coupled superlattices grown on (001) faces of cubic substrates, e.g. based on materials combinations as Co/Cu, Fe/Si, Co/Cr, or Fe/Cr, the magnetic states evolve under competing influence of bilinear and biquadratic exchange interactions, surface-enhanced four-fold in-plane anisotropy, and specific finite-size effects. Using phenomenological (micromagnetic) theory, a comprehensive survey of the magnetic states and reorientation transitions has been carried out for multilayer systems with even number of ferromagnetic sub-layers and magnetizations in the plane. In two-layer systems (N=2) the phase diagrams in dependence on components of the applied field in the plane include ``swallow-tail'' type regions of (metastable) multistate co-existence and a number of continuous and discontinuous reorientation transitions induced by radial and transversal components of the applied field. In multilayers (N \ge 4) noncollinear states are spatially inhomogeneous with magnetization varying across the multilayer stack. For weak four-fold anisotropy the magnetic states under influence of an applied field evolve by a complex continuous reorientation into the saturated state. At higher anisotropy they transform into various inhomogeneous and asymmetric structures. The discontinuous transitions between the magnetic states in these two-layers and multilayers are characterized by broad ranges of multi-phase coexistence of the (metastable) states and give rise to specific transitional domain structures.Comment: Manuscript 34 pages, 14 figures; submitted for publicatio

Hippocampal pyramidal cells: the reemergence of cortical lamination

The increasing resolution of tract-tracing studies has led to the definition of segments along the transverse axis of the hippocampal pyramidal cell layer, which may represent functionally defined elements. This review will summarize evidence for a morphological and functional differentiation of pyramidal cells along the radial (deep to superficial) axis of the cell layer. In many species, deep and superficial sublayers can be identified histologically throughout large parts of the septotemporal extent of the hippocampus. Neurons in these sublayers are generated during different periods of development. During development, deep and superficial cells express genes (Sox5, SatB2) that also specify the phenotypes of superficial and deep cells in the neocortex. Deep and superficial cells differ neurochemically (e.g. calbindin and zinc) and in their adult gene expression patterns. These markers also distinguish sublayers in the septal hippocampus, where they are not readily apparent histologically in rat or mouse. Deep and superficial pyramidal cells differ in septal, striatal, and neocortical efferent connections. Distributions of deep and superficial pyramidal cell dendrites and studies in reeler or sparsely GFP-expressing mice indicate that this also applies to afferent pathways. Histological, neurochemical, and connective differences between deep and superficial neurons may correlate with (patho-) physiological phenomena specific to pyramidal cells at different radial locations. We feel that an appreciation of radial subdivisions in the pyramidal cell layer reminiscent of lamination in other cortical areas may be critical in the interpretation of studies of hippocampal anatomy and function