State-selective study of the direct double photoionization of the Ne valence shell

Cross sections for double photoionization of the Ne L shell into the 2s2p{^5 3}P^0} and ^1P^0 and the 2s^02p^6 ^1S^e states were measured for energies from threshold up to 150 eV, using photon induced fluorescence spectroscopy. Both 2s2p^5 channels were observed with comparable magnitude in contradiction to a propensity rule based on the Wannier-Peterkop-Rau theory. A comparison of the summed ^3P^0 and ^1P^0 cross sections with MBPT calculations results in a deviation of 50%.

Influence of the electronic shell structure on the elastic scattering of heavy ions

The interatomic potential of the system I - I at intermediate and small distances is calculated from atomic DFS electron densities within a statistical model. Structures in the potential, due to the electronic shells, are investigated. Calculations of the elastic differential scattering cross section for small angles and several keV impact energies show a detailed peak pattern which can be correlated to individual electronic shell interaction.

Equilibrium K-shell excitation of highly ionized neon

Augerelectron emission from foil-excited Ne-ions (6 to 10 MeV beam energy) has been measured. The beam-foil time-of-flight technique has been applied to study electronic transitions of metastable states (delayed spectra) and to determine their lifetimes. To achieve a line identification for the complex structure observed in the prompt spectrum, the spectrum is separated into its isoelectronic parts by an Augerelectron-ion coincidence correlating the emitted electrons and the emitting projectiles of well defined final charge states q_f. Well resolved spectra were obtained and the lines could be identified using intermediate coupling Dirac-Fock multiconfiguration calculations. From the total KLL-Augerelectron transition probabilities observed in the electronion coincidence experiment for Ne (10 MeV) the amount of projectiles with one K-hole just behind a C-target can be estimated. For foil-excited Ne-projectiles in contrast to single collision results the comparison of transition intensities for individual lines with calculated transition probabilities yields a statistical population of Li- and Be-like configurations.

Core-Shell Assisted Bimetallic Assembly of Pt and Ru Nanoparticles by DNA Hybridization

We have discovered that the current protocols to assemble Au nanoparticles based on DNA hybridization do not work well with the small metal nanoparticles (e.g. 5 nm Au, 3.6 nm Pt and 3.2 nm Ru particles). Further investigations revealed the presence of strong interaction between the oligonucleotide backbone and the surface of the small metal nanoparticles. The oligonucleotides in this case are recumbent on the particle surface and are therefore not optimally oriented for hybridization. The nonspecific adsorption of oligonucleotides on small metal nanoparticles must be overcome before DNA hybridization can be accepted as a general assembly method. Two methods have been suggested as possible solutions to this problem. One is based on the use of stabilizer molecules which compete with the oligonucleotides for adsorption on the metal nanoparticle surface. Unfortunately, the reported success of this approach in small Au nanoparticles (using K₂BSPP) and Au films (using 6-mercapto-1-hexanol) could not be extended to the assembly of Pt and Ru nanoparticles by DNA hybridization. The second approach is to simply use larger metal particles. Indeed most reports on the DNA hybridization induced assembly of Au nanoparticles have made use of relatively large particles (>10 nm), hinting at a weaker non-specific interaction between the oligonucleotides and large Au nanoparticles. However, most current methods of nanoparticle synthesis are optimized to produce metal nanoparticles only within a narrow size range. We find that core-shell nanoparticles formed by the seeded growth method may be used to artificially enlarge the size of the metal particles to reduce the nonspecific binding of oligonucleotides. We demonstrate herein a core-shell assisted growth method to assemble Pt and Ru nanoparticles by DNA hybridization. This method involves firstly synthesizing approximately 16 nm core-shell Ag-Pt and 21 nm core-shell Au-Ru nanoparticles from 9.6 nm Ag seeds and 17.2 nm Au seeds respectively by the seed-mediated growth method. The core-shell nanoparticles were then functionalized by complementary thiolated oligonucleotides followed by aging in 0.2 M PBS buffer for 6 hours. The DNA hybridization induced bimetallic assembly of Pt and Ru nanoparticles could then be carried out in 0.3 M PBS buffer for 10 hours.

Corner Flows in Free Liquid Films

A lubrication-flow model for a free film in a corner is presented. The model, written in the hyperbolic coordinate system ξ = x² – y², η = 2xy, applies to films that are thin in the η direction. The lubrication approximation yields two coupled evolution equations for the film thickness and the velocity field which, to lowest order, describes plug flow in the hyperbolic coordinates. A free film in a corner evolving under surface tension and gravity is investigated. The rate of thinning of a free film is compared to that of a film evolving over a solid substrate. Viscous shear and normal stresses are both captured in the model and are computed for the entire flow domain. It is shown that normal stress dominates over shear stress in the far field, while shear stress dominates close to the corner.

Análisis de la presencia de petroleras occidentales y la agudización de conflictos político-económicos en el Delta del Níger. Caso: la Royal Dutch Shell y el Movimiento para la Emancipación del Delta del Níger (MEND) 2006-2010

La región del Delta del Níger es uno de los territorios, sino el principal, en otorgarle a Nigeria numerosas regalías por la exportación de petróleo, sin embargo el escaso beneficio que recibe su población genera conflicto en la región. La alta contaminación provocada por empresas petroleras como la Royal Dutch Shell (RDS), la violación de Derechos Humanos y la estrecha relación que mantiene la multinacional con el Gobierno, se han convertido en los motores del conflicto. Es debido a esto que grupos armados como el Movimiento para la Emancipación del Delta del Níger (MEND), han emprendido acciones con el fin de controlar los recursos, cometiendo robos de petróleo y actos de violencia que constituyen represalias por el trato que la industria petrolera ha dado a la población del Delta. No obstante, el conflicto se ha ido alejando de sus objetivos iniciales en tanto que se ha convertido en un negocio lucrativo, ha producido mayores índices de pobreza y se ha generado un círculo de violencia entre las empresas petroleras, el gobierno nigeriano y los grupos armados. De ahí que el Delta del Níger constituya una región importante no sólo debido a sus altas producciones de petróleo, sino porque además representa una zona altamente compleja que envuelve a ciudadanos, gobiernos y petroleras.

COMP1204: Programming the Shell - Apple Handbook (2013)

This is optional reading, it provides a very nice and clear reference to BASH with references to CShell