Volume 11 / Fascículo 1-4
Descarregar revista

ABSTRACT—A new method for accurate determination of instrumental time delays in measurements of half-lives using an electron magnetic spectrometer is presented. Lifetimes of the order of 100 ps can be obtained from curves of the centroid vs energy. 

ABSTRACT —Lfluorescence yield of Tl has been measured by comparing the relative intensities of the K and L1-X-ray spectra. 

ABSTRACT —Proton-induced K-shell X-ray production cross sections for Ar and Kr are measured in the incident energy ranges 0.185 —2 MeV and 0.5 — 2 MeV, respectively, using ion implanted targets. 

ABSTRACT — Measurements of thermal hysteresis in the elastic constant C33, and its associated ultrasonic attenuation α33 for single crystal dysprosium have been carried out using CdS thin film transducers. 

ABSTRACT—New high precision measurements of the electrical resistivity and its thermal derivative for a high quality terbium single crystal along a basal direction are presented and discussed in connection with the para-antiferromagnetic and anti-ferromagnetic transitions. 

ABSTRACT — The ef scattering models of Kasuya and Abel’skii—Irkhin are tested against experimental data on the thermopower of several rare-earth intermetallic compounds (Gd Zn, Gd Cd, Tb Zn). Good agreement is obtained for Gd Zn but not for Tb Zn; for Gd Cd the present data are inconclusive.  

ABSTRACT — We compare experimental data on the low-frequency dielec tric relaxation time...

The passage of an ionizing radiation through a material medium gives rise to the ionization and excitation of its atoms or molecules. The electronic energy of excitation is then dissipated non radiatively through collisional processes or internal extinction, or is radiatively emitted as photons. 

A set of inuclear Stopping correction factors to be used in the analysis of D.S.A. experiments by means of the LSS theory is presented. The results are derived from experimental determinations of the slowing down of 28Si ions in several backings, ranging from carbon to uranium. 

Data are presented for the linearity of photoionization detectors coupled to scintillators, mainly for gas proportional scintillation counters and also for other detecting media. The influence of electronic noise for low charge gain is considered.

The probabilities per « particle of shake-off in the K and L shells of ?4°Po have been determined by α-X ray coincidence experiments. 

ABST RACT — HoVO4 is a Van Vleck paramagnet with a susceptibility which is large perpendicular to the tetragonal crystal axis, but very small parallel to this axis.  

ABSTRACT — Dark current as a function of temperature has been used to study the ferro-paraelectric phase transition in Bi0.08Sb0.92SI. 

ABSTRACT — The proton spin-lattice relaxation time T, has been measured as a function of frequency and temperature in the nematic phase of hexyloxyazoxybenzene completely deuterated on the benzene rings (6.OAB-D8). 

ABSTRACT —The dynamics of disc-like molecules in the isotropic and mesomorphic (columnar) states is studied by the NMR _ technique. 

RESUME — Dans cet article nous passons en revue certaines des propriétés physiques du polyacétyléne non dopé et dopé, telles qu’elles ont été étudiées en France récemment. Nous insistons en particulier sur certains travaux concernant le matériau non dopé ...

ABSTRACT — Fluorescence and phosphorescence of cumene and of tryptophan in rigid matrices of methylcyclohexane and ethanol were measured at 77 K as a function of concentration. 

ABSTRACT — The atomic structure of the Laves phases TiFe, and TiMn, has been refined by X-ray diffraction from single crystals. The interatomic distances have been calculated and discussed in terms of the contraction of atoms in these structures. 

© 2019 Sociedade Portuguesa de Física