[en] Thin films of SiO deposited on Si substrates by thermal evaporation have been characterised by the analysis of infrared absorption bands and optical constants determination. The structure of the films has been studied in terms of the RBM (Random Bonding Model) and a deviation from the pure RBM structure has been found in the relative concentration of the different tetrahedra Si-O_y-Si_4-y (y=1-4) and in the presence of an additional contribution of Si-O₄ tetrahedra confirmed by the optical properties. Comparative study of films deposited under different conditions and with different thickness suggests that the local arrangement of Si and O atoms, the oxygen content of the films and morphological changes in the films must be considered to account for all the effects observed

[en] A thin film (approx. 30 nm) of anodic hafnium oxide on hafnium is analysed by sputtering with 3 keV Ar⁺ ions and Auger electron spectroscopy (AES). Changes observed in the Auger line-shape of hafnium during the ion bombardment are interpreted as formation of new oxide phases caused by sputtering induced depletion of oxygen in the surface. (author)

[en] Tantalum silicide films of ∼ 200 nm thick and composition TaSi₂ were obtained by co-sputtering in a Varian 3120 S-gun magnetron system. The films were then introduced in an AES spectrometer and bombarded with Ar⁺ ions of different energies in order to obtain surfaces of different compositions as a consequence of preferential sputtering effects and their dependence on the energy of the primary ions. Lowering the energy of the Ar⁺ ions resulted in surfaces very rich in tantalum. The interactions of these surfaces with oxygen at low pressures (10^-8-10^-5 Torr) and at room temperature then have been studied comparatively by Auger electron spectroscopy. Reference experiments with pure Si and Ta allowed the comparison with those of the different silicide surfaces. It is found that the oxygen uptake depends on the Ta content so that the richer in Ta the surface is, the higher the O₂ incorporation. Furthermore, the uptake rate at the different TaSi_x surfaces resembles better the measured rate for pure Ta than that observed for pure Si. It has been observed also that the oxidation of Si is enhanced over that of pure silicon in all the surfaces studied here. Besides, the enhancement depends on the tantalum content. (author)

[en] Polycrystalline tantalum surfaces were chemically analyzed by Auger electron spectroscopy. The tantalum samples were subjected to various thermal and chemical treatments usually employed prior to the formation of dielectric anodic films. After each treatment, the incorporation or elimination of impurities on the surface was observed. The evolution with temperatures up to 2800⁰ K of all the impurities on the tantalum and tantalum oxide surfaces was studied. (Auth.)

[en] We review 16 cases of traumatic diaphragmatic rupture for the purpose of assessing the use of the different imaging methods in the diagnosis. Thirteen patients were males and 3 females, between 18 and 71 years of age, with a mean age of 37 years. The diagnosis was based on imaging methods in 13 patients and in the remaining 3, on surgical findings. Chest x-ray disclosed the presence of loops in the chest cavity in 7 cases, elevation of the hemidiaphragm in 4 and normal diaphragm in the remaining 5. CT was performed in 4 patients. The signs observed were loops lateral to the diaphragm, diaphragmatic rupture and the ''the missing diaphragm'' sign. Ultrasound was useful in detecting the free fluid and abdominal organ involvement, but it was less valuable in detecting the state of the diaphragm itself. The barium studies showed the hernial ring in all the cases reviewed. Author (24 refs.)

[en] Published in summary form only

[en] During ion bombardment of many metallic oxides a thin oxygen depleted layer is built up on top of the stoichiometric oxide. The characterisation of this layer is demonstrated using quantitative AES and XPS: Based on the mean electron escape depth, the mole fractions of metal and oxygen are derived from the intensity ratio as a function of the layer thickness. The latter is determined by variation of the effective escape depth (emission angle variation). From the chemical shift of the metal XPS peaks lower oxides can be detected, with the respective peak areas giving their concentration. The example of anodic Ta²O⁵ (30 nm thickness) yields the following results with 3 keV ar⁺ bombardment: The thickness of the altered layer with 20 at.-% oxygen loss (Xsub(Ta) = 0.5) is 2.5+-0.7 nm, and the reduction proceeds to metallic Ta, which is present besides the oxides TaO and TaO². (orig.)

[en] In the last decade the Accelerator Driven Systems (ADS) appear among the most promising transmutation systems. The transmutation efficiency of a TRU thorium fuel lead cooled ADS based in a multiple recycling strategy has been analyzed in this paper. There is a substantial cumulative elimination of ²³⁹Pu, ²⁴¹Am, ²⁴⁰Pu, ²³⁷Np, ²⁴¹Pu and ²⁴²Pu, which grow with the number of cycles. On the other hand the curium isotopes are being produced in the system along the reloads, but they represent less than 5 % of the TRU waste in the last discharge (<1.5% of the total TRU loaded). The evolution of the TRU composition of the discharge means reducing the quality of the TRU waste, devaluating the quantity of fissile isotopes. Multiple recycling allows burning large amounts of TRU, and changing the composition of the final TRU waste from a ²³⁹Pu enriched one, to a minor actinides enriched TRU waste. The final waste for this stage could be suitable to be treated in an ADS of a different type, or with a different fuel, still in study. (author)

[en] A model calculation is presented for the quantitative evaluation of AES sputtering profiles of thin layers in the case of preferential sputtering and a contamination overlayer. The model is based on the statistical contribution to depth resolution, the escape depth effect correction and the preferential sputtering model of Ho et al. (1976). Applications to measured AES sputtering profiles of the anodic oxides Ta₂O₅ and Nb₂O₅ allow the determination of the thickness and the oxygen content of the contamination overlayer. (author)

[en] Thin films of anodically formed Ta₂O₅ and Nb₂O₅ on polycrystalline Ta and Nb, respectively, are analysed with AES during sputtering with Ar⁺ ions at energies between 0.5 keV and 5 keV. A sputtering induced depletion of oxygen at the surface is observed in both oxides. The kinetics of this depletion and the steady-state composition at the surface of the samples are studied as a function of the primary ion energy. The results are interpreted using a modification of the model of Ho et al. (1976) for the preferential sputtering of alloys. The thickness of the transient layer increases non-linearly from 1.6 to 3.4 nm with increasing ion energy. Below 2 keV, the surface depletion of oxygen increases with decreasing ion energy and is constant above 2 keV up to 5 keV. The results are similar for both oxides. At 2 keV, the minimum measured width of the oxide/metal interface is 2 nm for Ta₂O₅/Ta and is about two times larger for Nb₂O₅/Nb. In both cases it increases with the square root of the ion energy and it is independent on the oxide layer thickness between 10 nm and 150 nm. (author)