[en] The ³He and ⁴He longitudinal and transverse response functions are determined from an analysis of the world data on quasi-elastic inclusive electron scattering. The corresponding Euclidean response functions are derived and compared to those calculated with Green's function Monte Carlo methods, using realistic interactions and currents. Large contributions associated with two-body currents are found, particularly in the ⁴He transverse response, in agreement with data. The contributions of two-body charge and current operators in the ³He, ⁴He, and ⁶Li response functions are also studied via sum-rule techniques. A semi-quantitative explanation for the observed systematics in the excess of transverse quasi-elastic strength, as function of mass number and momentum transfer, is provided. Finally, a number of model studies with simplified interactions, currents, and wave functions is carried out to elucidate the role played, in the full calculation, by tensor interactions and correlations

[en] We determine the Coulomb sum for ⁴He using world data on ⁴He(e, e') and compare the results to calculations based on realistic interactions and including two-body components in the nuclear charge operator. We find good agreement between theory and experiment using free-nucleon form factors. The apparent reduction of the in-medium G_ep implied by IA-interpretation of the L/T-ratios measured in ⁴He(e,e'p) and ⁴He([vec]e, e'p) is not confirmed

[en] We determine the Coulomb sum for ⁴He using the world data on ⁴He(e,e') and compare the results to calculations based on realistic interactions and including two-body components in the nuclear charge operator. We find good agreement between theory and experiment when using free-nucleon form factors. The apparent reduction of the in-medium G_Ep implied by IA-interpretation of the L/T-ratios measured in ⁴He(e,e'p) and ⁴He(e→,e'p→) is not confirmed

[en] The recrystallization of polycrystalline pure titanium has been studied ''in situ'' and in real time by Synchroton White Beam X-Ray Topography. Synchrotron X-ray topographs made at different temperatures allow us to determine that in addition to the well known recrystallization in the α phase, two other ones were occuring when the samples were annealed through the phase transformation point upward (in the β phase) and downward (in the α phase). The recrystallization proces and the crystalline quality of the grains have then been determined. (author)

No abstract available

[en] The temperature dependence of the Hall resistivity of thin epitaxial UPd₂Al₃ films with low defect densities is investigated. It shows a minimum at 6 K for fields up to 12 T. This feature is attributed to the superposition of a coherence-derived low-temperature Hall coefficient and a skew-scattering contribution. Further implications on the Hall effect in the coherence regime of Kondo lattices are discussed

[en] Grain boundary migration has been investigated in prestrained monocrystalline specimens of aluminum in situ, continuously and at temperatures ranging from 415 to 610 degrees C by synchrotron (polychromatic) x-ray topography (SXRT). In general, new (recrystallized) grains nucleate at prepositioned surface indentations and expand into the prestrained matrix, revealing complex evolution of crystallographic facets and occasional generation of (screw) dislocations in the wake of the moving boundaries. Analysis of corresponding migration rates for several faceted grain boundaries yields activation energies ranging from 56 to 125 kCal/mole, depending on the grain boundary character. It is concluded that grain boundary mobility is a sensitive function of grain boundary inclination, resulting in ultimate survival of low-mobility (faceted) inclinations as a natural consequence of growth selection. Advantages and disadvantages associated with measurement of grain boundary migration by SXRT are enumerated and correspondi

[en] A camera designed for in situ synchrotron radiation X-ray topographic studies at high temperature and under ultra high vacuum (UHV) is described. Temperatures about 1000 K at 10^-7 Pa can be easily reached with this equipment. Thus solid-state phenomena in bulk samples (thickness 1 mm for aluminium) can be followed on a wide area (10 x 15 mm) by X-ray topographs recorded on films or plates or using a TV camera. These performances are demonstrated in the case of aluminium recrystallization. (Auth.)

[en] Kinetics of grain boundary migration have been investigated in prestrained monocrystalline specimens of aluminum in situ at temperatures ranging from 415 to 610 degrees C by synchrotron (polychromatic) x-ray topography (SXRT). In general, new (recrystalized) grains, which nucleate at prepositioned surface indentations and subsequently grow into the prestrained matrix, transform progressively from random to faceted configurations. Analysis of corresponding migration rates as a function of temperature for several faceted boundaries yields activation energies ranging from about 56 to 105 kcal/mole, in contrast to previously reported values, obtained by repetitive cooling and reheating cycles, ranging from about 15 to 35 kcal/mole. This disparity in measured activation energy is attributed to variation of grain boundary mobility with grain boundary inclination, and ultimate survival of low-mobility (faceted grain boundary inclinations, as a natural consequence of growth selection

[en] We have built a polarimeter in order to measure the electron beam polarization in hall C at JLAB. Using a superconducting solenoid to drive the pure-iron target foil into saturation, and a symmetrical setup to detect the Moller electrons in coincidence, we achieve an accuracy of <1%. This sets a new standard for Moller polarimeters