The Comprehensive Yeast Genome Database (CYGD) compiles a comprehensive data resource for information on the cellular functions of the yeast Saccharomyces cerevisiae and related species, chosen as the best understood model organism for eukaryotes. The database serves as a common resource generated by a European consortium, going beyond the provision of sequence information and functional annotations on individual genes and proteins. In addition, it provides information on the physical and functional interactions among proteins as well as other genetic elements. These cellular networks include metabolic and regulatory pathways, signal transduction and transport processes as well as co-regulated gene clusters. As more yeast genomes are published, their annotation becomes greatly facilitated using S.cerevisiae as a reference. CYGD provides a way of exploring related genomes with the aid of the S.cerevisiae genome as a backbone and SIMAP, the Similarity Matrix of Proteins. The comprehensive resource is available under http://mips.gsf.de/genre/proj/yeast/.

Carbon films with up to 32 at. % of nitrogen have been prepared with ion beam assisted magnetron, using a N2+/N+ beam at energies between 50 and 300 eV. The composition and density of the films vary strongly with the deposition parameters. EELS, SXS, XPS, and IR studies show that these a-C: N films are mostly graphitic and have up to 20% sp3 bonding. Nitrogen is mostly combined with carbon in nitrile (C ≡ N) and imine (C=N) groups. It is shown by RBS and NDP that density goes through a maximum as the average damage energy per incoming ion increases. Positron annihilation spectroscopy shows that the void concentration in the films goes through a minimum with average damage energy. These results are consistent with a densification induced by the collisions at low average damage energy values and induced graphitization at higher damage energy values. These results are similar to what is observed for Ar ion assisted deposition of a-C films. The mechanical properties of these films have been studied with a nanoindenter, and it was found that the hardness and Young's modulus go through a maximum as the average damage energy is increased. The maximum of mechanical properties corresponds to the minimum in the void concentration in the film. Tribological studies of the a-C: N show that the friction coefficient obtained against diamond under dynamic loading decreases strongly as the nitrogen composition increases, this effect being more pronounced at low loads.

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Optical interference filters made by layers of optical coatings are used to shape and transport laser beams. If a defect is present in the stack (cosmetic defect, stoichiometry defect, absorption band…), and high laser power density is reached, a strong energy into the material can be deposited involving the destruction of the coatings (either by melting or mechanical failure). One of the key methods to achieve high performance coatings is to reduce such defects as much as possible. Hafnia (HfO2) coatings are undoubtedly one of the most successful materials for high power laser applications. Associated with a low index material such as silica, high laser induced damage threshold (LIDT) interference filters can be achieved. Hafnia is often the LIDT limiting factor. During the evaporation HfO2 particles create buried defects in the deposited material. These defects are sources of the coating damage during laser irradiation. To avoid this phenomenon we have evaporated metallic hafnium that was oxidized by oxygen inlet into the vacuum chamber or use an oxygen ion beam bombardment during the film growth. Argon or, better, xenon ions in the beam produced densities as high as 99% of the bulk, with low water content, and an improved optical transmission in the mid infrared window. This article deals with the optimization of such a deposition process regarding coating density, mechanical stresses, and optical properties (optical absorption). Films deposited by HfO2 evaporation are compared especially using photothermal mapping. The stoichiometry of the defects determined thanks to localized Auger spectroscopy clearly indicates how injurious such defects could be for high laser flux applications. Finally, laser damage thresholds of the films at 1.06 μm are measured and possible damage mechanism discussed.

Structure of the interfacial region between polycarbonate and plasma-deposited SiN 1.3 and SiO 2 optical coatings studied by ellipsometry Hafnium oxide presents a strong interest either for optical coatings or for microelectronic applications. An important parameter to control is its chemical interaction with silicon oxide, since those two materials are usually in direct contact in both applications: For optical coatings, silica is the low refractive index used to make interference filters ͓see M. R. Kozlowski, Thin Films for Optical Systems ͑Marcel Dekker, New York͔͒, in microelectronics HfO 2 could be used as a gate insulator in metal-oxide semiconductor technology ͓B. H. Lee, Tech. Dig. Int. Electron Devices Meet. 99, 133͔. One interesting characterization method of the created interface is infrared spectroscopy in the so-called multiple internal reflection ͑MIR͒ technique. Mono-and bilayers of HfO 2 and SiO 2 have been deposited on germanium substrates by e-beam evaporation and ion beam sputtering. MIR measurements made on those samples show that when HfO 2 is deposited on SiO 2 , parts of the Si-O-Si bonds are broken and Hf-O-Si bonds, representative of hafnium silicate (HfSiO 4 ), are formed at the interface. Hafnium and silicon oxide have also been coevaporated in a reactive atmosphere to deposit the silicate and confirm the position of the Hf-O-Si bond. The results obtained by MIR are confirmed with x-ray photoelectron spectroscopy and transmission electron microscopy analysis.

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Nonhydrogenated diamondlike carbon films have been prepared by dual ion beam sputtering and ion-beam-assisted magnetron. The assistance parameters—ion energy, ion mass, ion flux/atom flux—have been systematically varied, and the films have been characterized by Rutherford backscattering spectroscopy, high-resolution transmission electron microscopy, electron energy loss spectroscopy, positron annihilation spectroscopy, Raman spectroscopy, and nanoindentation. It was found that the density and the degree of disorder of the films go through a maximum with ion energy, and the void concentration goes through a minimum. Microstructure analysis shows that the films are mostly sp2 bonded, with a maximum of about 16% concentration of sp3 bonding from the largest values of density. The evolution of density with ion flux and energy is consistent with a combined effect of atomic displacements in the film leading to densification, and damage buildup leading to progressive graphitization as the energy is increased. The large hardness/elastic modulus ratios obtained should lead to excellent friction properties.

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