How small can superconductors be? For isolated nanoparticles subject to quantum size effects, P.W. Anderson in 1959 conjectured that superconductivity could only exist when the electronic level spacing δ is smaller than the superconducting gap energy Δ. Here we report a scanning tunnelling spectroscopy study of superconducting lead (Pb) nanocrystals grown on the (110) surface of InAs. We find t...

A structural study has been performed on the polar ZnO(0001̄)-(1×1) surface using ab initio calculations and low-energy electron diffraction (LEED). The experiment was performed with a delay line detector LEED system to minimize electron damage of the surface. The top O-Zn interlayer spacing was found to be 0.51 ± 0.04 Å, a 16% ± 6% contraction from the bulk spacing. The second and third interla...

introduction:nitrate entrance to water bodies can cause eutrophication and decrease quality of them, furthermore it can effect on human health so concentration of nitrate must be at defined standard level. there are several methods for reduction or removal of nitrate in water such as ion exchange, reverse osmosis, electrodialysis and denitrification. microbial denitrification of nitrate in anox...

The non-coupled substrate oxidation mediated by components of the electron transport chain that are not coupled to energy accumulation (such as plant alternative oxidase and rotenone-insensitive NADH dehydrogenases) and uncoupled respiration are peculiar features of plant mitochondria. The physiological significance of such energy-wasting oxidation processes is still debated. It is proposed tha...

This review article highlights the recent evolution of research on laser wakefield accelerators, which has, in record time, led to the production of high quality electron beams beyond the GeV level, using compact laser systems. As shown here, the most significant breakthroughs allow to produce stable, high peak current and high quality electron beams, with a fine control of the charge, of the r...

Electron-ion collisions are one of the main processes that drive the relaxation towards equilibrium. Most theoretical approaches of the connected energy transfer consider only independent binary collisions (see, e.g., Refs. [1-3]); collective excitations are neglected. Although decoupled electron-ion modes have only small effects [4], Dharmawardana & Perrot found strongly reduced energy transfe...

Ordered binary oxide films of vanadium oxide have been prepared on an aluminum oxide film supported on Mo~110! under ultrahigh vacuum conditions and characterized by various surface analytical techniques. Auger electron spectroscopy, low energy electron diffraction, high-resolution electron loss spectroscopy, x-ray photoelectron spectroscopy and ion scattering spectroscopy indicate that the van...

Laser-wakefield accelerators are compact devices capable of delivering ultra-short electron bunches with pC-level charge and MeV-GeV energy by exploiting the ultra-high electric fields arising from the interaction of intense laser pulses with plasma. We show experimentally and through numerical simulations that a high-energy electron beam is produced simultaneously with two stable lower-energy ...

The effect of acceptor energy level on electron transfer rate in blends of the polymer solar-cell material poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) is studied using time-resolved fluorescence. Fast electron transfer in less than 2 ps is observed for a driving force between 0.2 and 0.6 eV and t...

Total electron scattering cross sections for pyrazine in the energy range 10-500 eV have been measured with a new magnetically confined electron transmission-beam apparatus. Theoretical differential and integral elastic, as well as integral inelastic, cross sections have been calculated by means of a screening-corrected form of the independent-atom representation (IAM-SCAR) from 10 to 1000 eV i...