No abstract available

[en] A drift tube-mass spectrometer was used to measured the mobility of CH₅⁺, C₂H₅⁺ and C₃H₅⁺ in CH₄ over a wide range of the reduced field strength, E/N, from 15 to 500 Td (1 Td = 10^-17 V cm²). The zero-field mobilities of these ions turn out to be lower than those predicted by Langevin's polarization-limit theory. The low field mobilities for the first two ions are in good agreement with previous values obtained from other techniques. For E/N > 100 Td, the mobility of CH₅⁺ is lower than that of C₂H₅⁺ sm-bullet suggesting a proton transfer process between CH₅⁺ and CH₄. The mobility curves show a pronounced maximum over the range 200-300 Td

[en] Structural characterization and electronic properties of the LaNi_0.95M_0.05O₃ (M = Mo, W, Sb, Ti, Cu, Zn) perovskite-like system are reported. These compounds can be regarded as being derived from LaNiO₃ by partial substitution of Ni³⁺ in this material by M⁶⁺, M⁵⁺, M⁴⁺, or M²⁺ formal cations, with a partial reduction of Ni³⁺ to Ni²⁺ taking place. X-ray powder diffraction data were analyzed by means of the Rietveld method and show that all the title materials present perovskite-type structure with a rhombohedral (S.G. R bar 3c) or orthorhombic (S.G. Pbnm) symmetry, depending on the nature of the M cation. In all cases, Ni and M cations are placed at random in octahedral B-sites of perovskite structure. Electrical resistivity measurements (four probe method) show metal-to-insulator (M-I) transitions for M = Mo, W, Ti, Cu, Zn at temperatures of about 50K and a semiconductor behavior for the Sb sample in the whole temperature range explored. Magnetic susceptibility measurements show the presence of weak ferromagnetic interactions for M = Sb and Pauli paramagnetism for the remaining compounds

No abstract available

[en] Absolute differential and total cross sections for double electron capture by H⁺ in collision with Kr have been measured for energies between 1.0 to 5 keV. The angular range of measurements was ±3.5 degrees in the laboratory frame. The differential cross sections exhibit well resolved oscillations over the angular and energy range under investigation. There are not data differential cross sections to compare with. The absolute value of the total cross sections reported here is about 30% higher than those previously reported. A plot of log σ_1-1 vs projectile velocity follows a linear trend

[en] Ion mobilities of 0^-, O₂^-, O₃^- and O₂⁺, and rate coefficients for the reactions leading to the formation of O₂^- and O₃^- have been measured using a pulsed Townsend apparatus. The oxygen density was 1.3 to 16.8 x 10²⁴ m^-3 and the reduced field strength E/N was 7.6 to 11.5 x 10^-20 V m². Fitting to the ion transients was done from an improvement to the earlier analysis of Burch and Geballe. Resulting values for the two- and three-body rate constants and for the ion mobilities have been found in good agreement with previous values reported by other workers who used lower gas densities. Also, values of the ionization and attachment coefficients could be derived from this study

[en] Absolute differential and total cross sections have been measured for the single electron capture of Ne⁺ in He at impact energies between 0.5 and 5 keV. Oscillations in the differential cross sections are interpreted as the envelope of the fast oscillations due to the interference of the scattering amplitudes. Total cross sections are in agreement with previous experiments. (orig.)

[en] This report provides a handbook of recommended cross-section and rate-coefficient data for inelastic collisions between hydrogen, helium and lithium atoms, molecules and ions, and encompasses more than 400 different reactions of primary interest in fusion research. Published experimental and theoretical data have been collected and evaluated, and the recommended data are presented in tabular, graphical and parametrized form. Processes include excitation and spectral line emission, charge exchange, ionization, stripping, dissociation and particle interchange reactions. The range of collision energies is appropriate to applications in fusion-energy research

[en] This work involves carrying out a follow-up of the surface damage to super duplex SAF 2507 stainless steel, cycle deformed with a total deformation range Δε_t = 0.8%, until the first fissures appear and correlate with the structure of dislocations. A thin layer preparation technique for transmission electron microscopy was used for this purpose, which preserves one of the faces of the fatigued test piece containing all the surface information. The dislocation structures, crystallographic characteristics and the initiation of fissures in the deformation bands with the surface damage can be studied and correlated. The mechanical tests were carried out for deformation control with a deformation speed of dε/dt = 3 x 10^-3 s^-1. The tests were done for different numbers of cycles and the surface damage was observed under an optic microscope with the contrasting differential interference technique, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The propagation of the slippage lines on the surface could be observed from the austenitic to the ferritic phase, as well as bands of intense deformation and the formation of persistent slippage bands (PSBs), initiation and propagation of fissures relating the structure of dislocations on the surface and just below this in order to connect the location of the plastic deformation and the beginning of the fissure (CW)

[en] Data are presented on H^- negative ion formation in H⁺ and H⁰ collisions with alkaline-earth metal vapor targets. Data on H^- formation in multiple-collision thick targets is reported, as well as H^- formation via single and double electron capture in a single collision. Low energy angular scattering data is also presented for the double electron capture process H⁺ → H^- in Mg