ABSTRACT — The paper reviews some of the problems encountered in the measurement and interpretation of electron-density measurements. The experimental problems are compared with those encountered in parallel studies of spin density distributions.
ABSTRACT — Four molecules have been studied by single crystal neutron diffraction: acetamide at 23 K, fluoroacetamide at 20 K, formamide oxime at 16 K, and 1,2-diformyl hydrazine at 15 K.
ABSTRACT — Ferroelastic transformations can be calculated, when an n-fold pseudo-rotation exists (the n-fold rotation being a symmetry element of the prototype lost in the lower symmetry ferroelastic phase ), by means of a transformation (rotation of axes) corresponding to the reorientation of the lattice vectors if distortion of the ferroelastic structure is taken into account.
ABSTRACT — Crystallization kinetics of the amorphous Se0.95, Bi0.95 alloy, prepared by quenching of the melt at 850 K, has been studied by calorimetric DSC measurements.
ABSTRACT — Thermal evolution of amorphous Se1-x, Bix (x = 0.05 at) coevaporated thin films has been characterized by electrical resistivity measurements and electron microscopy observations.
ABSTRACT —A size effect study of the intermediate phases MSI and MSII, on the crystallization of Fe40Ni38Mo4B18 (2826 MB) metallic glass has been carried out.
RESUME —Apartir de l’étude des modes normaux de vibration des molécules d’eau d’hydratation, par spectroscopie Raman, et de données de diffraction de Rayons-X nous repportons la orientation précise des hydrogénes dans le La2 (SO4)3 .9 H2O.
ABSTRACT — The standard representation recently proposed by the author, and applied in detail to structures based on cubic and hexagonal closest packings, has been extended to inorganic structures based on simple and on loose packings. This standard representation clearly shows that these structures have a much simpler atomic organization and are more interrelated than could be imagined using conventional ways of structure representation.
ABSTRACT — X-ray integrated intensities from two different crystals of VF2 have been collected using a CAD4 diffractometer.
ABSTRACT — Polyhedra around the atomic sites of the sigma phase structure were defined in a way similar to Wigner-Seitz cell and computer programs for the calculation of their volumes were written; the apllication to the sigma phase Mo3Co2 shows that again the J-sites exhibit a peculiar behaviour.
ABSTRACT — The o-phase structure V62 Co38 has been studied using an X-ray single-crystal diffractometer. Both size and electronic factors appear to account for a complete ordering of this phase which is approximately stoichiometric.
Few Portuguese names stand out, in the field of Atomic and Nuclear Physics, as brightly as that of Manuel Valadares.
ABSTRACT — The breaking of the SU(2)w collinear symmetry arising when leaving the forward direction in scattering processes is studied,
ABSTRACT —Avery sensitive a. c. method is described for the measurement of the Hall effect in metals. It uses a high quality lock’in amplifier with the oscillator incorporated, an operational power supply, and a low noise step-up transformer to rise the signal level.
ABSTRACT — Pyroelectric coefficient (λ) was investigated in crystals
ABSTRACT — Magnetoresistance studies of the intermetallic ferromagnetic TbZn compound have been performed for the first time, ...
ABSTRACT —In ultrahigh vacuum at 3 K (the ordinary condition of the interstellar matter) carbon can be quench-crystallized in Al-type ...
ABSTRACT — We studied the photodynamic action of singlet oxygen, generated by Rose Bengal bound to polystyrene beads, on the electron transport components of rat liver microsomes.
ABSTRACT — Optical measurement techniques have always played an important role in precision metrology.
RESUME — Dans un formalisme maxwellien de la mécanique des fluides incompressibles on montre comme on peut passer des équations relativistes ...