Volume 21 / Fascículo 1-4
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BSTRACT-Enhanced nuclear magnetism is of particular interest in Van Vleck paramagnets, in which the electronic ground state is a singlet or non-Kramers doublet. 

ABSTRACT - Quark-antiquark states in a chiral invariant four fermion interaction lagrangian without confinement are investigated. 

ABSTRACT -From the structural study of Fe-Si alloys with 75 wt.% Si it was possible to detect, beyond the well recognized phases - Si, FeSi, (α and β), 

ABSTRACT -The main features of the charge density distribution in the hexagonal Laves phase FeBe2 have been deduced from preliminary studies based on X-ray diffraction measurements carried out at room temperature in one single crystal. 

ABSTRACT-The time evolution operator for the quantum harmonic oscillator with time-dependent frequency is exactly obtained as a product of unitary operators. 

ABSTRACT - We present the characteristics of the ultraviolet spectra of T Tauri stars and summarise the relevance of ultraviolet Astronomy and its historical development. 

ABSTRACT - Fast, position sensitive gaseous detectors have been developed mostly to satisfy the needs of elementary particle physics experimentation. We present some examples of use of those devices in other applied fields, from astrophysics to biology and medical research. 

ABSTRACT - After a short analysis of classical superconductors, we discuss the atomic and electronic structure of the new superconductors. A strong atomic anisotropy with two-dimensional character can lead to thermodynamic fluctuations of the superconducting order parameter which do not favour the T, value nor the superconducting properties. 

ABSTRACT- A wire has a mass proportional to its length, the mass of a disk varies proportional to the squared radius, and the mass of an iron sphere is proportional to the third power of the radius. 

ABSTRACT -The paper discusses how modelling with the computer can help Physics Education, for students in a wide age range, from Primary School to University. Different kinds of computational modelling, including iterative dynamic models, 

ABSTRACT - Microgmulsions are mixtures of oil, water and “‘soap" (amphiphilic molecules). The Widom model of 1986 describes them by a spin 1/2 Ising model with competing interactions to nearest and further neighbors. We review the Monte Carlo simulations of this Widom model, for static and dynamic properties.  

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