Il Nuovo Cimento (1911-1923)

A total of 340 m of track of negative pions of momentum 1.3 GeV/c have been followed in emulsion, and pion interactions have been recorded. Special emphasis is placed on inelastic scattering on free protons (single meson production). The resulting angular and momentum distributions of the emitted particles are investigated and compared with previous experiments at similar energies. An attempt is made to explain these results on the basis of an isobar decaying into a nucleon and the slower pion. In the case of reaction π−+p → π− + π0+p, it appears that there exists an anisotropy in the isobar frame of reference, in which the slower pion is emitted predominantly backward, with respect to the isobar direction. The results are compared with the π-π coupling model. Angular and energy distributions of mesons emitted in nuclear interactions are investigated and compared with other results and Monte Carlo calculations. The meson multiplicity and energy degradation in these collisions are also discussed. Strange particles found during the investigation are analysed.

Viene descritto uno stimolatore elettronico, comandato da potenziali biologici, destinato a riprodurre meccanismi d’autoregolazione normalmente legati all’attività del sistema nervoso centrale. Si illustra una delle possibili applicazioni dell’apparecchio e si descrivono nei particolari alcuni dei circuiti che di esso fanno parte. The description is given of an electronic stimulator, triggered by bioelectric potentials, and designed in order to reproduce feed-back mechanisms, normally connected with the activity of the central nervous system. At each triggering pulse, the stimulator yields a series of rectangular pulses which are variable, within wide limits, in number, amplitude and width. A variable delay (from 0 to 2000 ms) may be also introduced, with respect to the bioelectric signal. An example of application is shown, and some circuits are described in detail.

In many problems involving wave propagation, the squares of the absolute values of the wave functions rather than the wave functions themselves are the physically observable quantities. These quantities are interpreted as energy densities in the case of electromagnetic radiation, for example, and as probability densities in quantum mechanics. The objective of the present paper is to give a theorem involving Fourier integrals which indicates a set of physical measurements of energy densities and probability densities in one-dimensional problems which lead to an essentially unique determination of the wave functions. For use in quantum mechanics, the measurements which are required can be expressed as the mean values of certain operators constructed from the position and momentum operators. These will also be given.

Si studia la possibilità che l’equazione di Schrödinger relativaal caso di forze di scambio di E. Majorana possa dedursi da una Hamiltoniana classica in cui il Potenziale è funzione anche delle velocità, mediante il solito metodo operatoriale su cui è basato il passaggio dalla meccanica ordinaria a quella quantistica.