Valence band excitations in V_2O_5

We present a joint theoretical and experimental investigation of the electronic and optical properties of vanadium pentoxide. Electron energy-loss spectroscopy in transmission was employed to measure the momentum-dependent loss function. This in turn was used to derive the optical conductivity, which is compared to the results of band structure calculations. A good qualitative and quantitative agreement between the theoretical and the experimental optical conductivity was observed. The experimentally observed anisotropy of the optical properties of V_2O_5 could be understood in the light of an analysis of the theoretical data involving the decomposition of the calculated optical conductivity into contributions from transitions into selected energy regions of the conduction band. In addition, based upon a tight binding fit to the band structure, values are given for the effective V3d_xy-O2p hopping terms and are compared to the corresponding values for alpha'-NaV_2O_5.Comment: 6 pages (revtex),6 figures (jpg

A versatile computational pipeline for bacterial genome annotation improvement and comparative analysis, with Brucella as a use case

We present a bacterial genome computational analysis pipeline, called GenVar. The pipeline, based on the program GeneWise, is designed to analyze an annotated genome and automatically identify missed gene calls and sequence variants such as genes with disrupted reading frames (split genes) and those with insertions and deletions (indels). For a given genome to be analyzed, GenVar relies on a database containing closely related genomes (such as other species or strains) as well as a few additional reference genomes. GenVar also helps identify gene disruptions probably caused by sequencing errors. We exemplify GenVar's capabilities by presenting results from the analysis of four Brucella genomes. Brucella is an important human pathogen and zoonotic agent. The analysis revealed hundreds of missed gene calls, new split genes and indels, several of which are species specific and hence provide valuable clues to the understanding of the genome basis of Brucella pathogenicity and host specificity

CVD MOLYBDENUM FILMS OF HIGH INFRARED REFLECTANCE AND SIGNIFICANT SOLAR ABSORPTANCE

Chemical Vapor Deposition (CVD) of thin films from molybdenum carbonyl (Mo (CO) 6) at 300 °C under atmospheric pressure has resulted in either reflective or black molybdenum, depending on the absence or presence of an oxygen bleed during the deposition. After post-deposition anneal, the reflective film exhibits an infrared reflectance of 98.7 % at 10 microns while the black film exhibits a solar absorptance of a = 0.74 and a thermal (500°C) emittance of en = 0.08, (en referring to the normal emittance). The reflectance of both films, before and after anneal, has been related to their composition, grain size, and crystal structure. In particular this has been done in the infrared for the reflective films and in the visible for the black films. The solar absorptance of both film types can be enhanced by one or two antireflection layers with only slight increases in the emittance. A bilayer of CVD silicon (700 Å) and silicon nitride (700 Å) on the annealed reflective film results in a = 0.75 and e (500 °C) = 0.05. A layer of CVD silicon nitride (750 Å) on the black film results in a = 0.91 and en (500°C) = 0.11. Both configurations have been tested for over 1000 hours at 500 °C in a roughing pump vacuum without measured deterioration