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Acoustical activity of isomorphous crystals Bi12GeO20 and Bi12SiO20 has been studied by measuring the splitting of degeneracy of transverse acoustical waves propagating along high symmetric direction with inelastic neutron scattering. One of the interesting results is that the left and right circularly polarized modes of acoustical phonons propagating along direction are subjected to different attenuation. This conclusion is verified by both kinds of crystals. The experimental result is observed for the first time in the study of acoustical activity. The life-time of the phonon with larger attenuation is found to be about 2×10-11 s. experimentally.

The rigorous solutions of the relativistic wave equation for neutrons are obtained in the case of slab-like uniform magnetic fields at perpendicular incidence. For all energy regions (from zero to ultra-relativistic), corresponding expressions of the one-dimensional scattering of neutrons, in particular, neutrons with very slow velocities, are studied. Finally, the corresponding transformations of the neutron's spin vectors are given.

The interference between the spinor components-of the polarized neutron beam passing through a> Mezei-coil is investigated. The. authors proposed, a method tc< detect the phase shift of the spinor components and to test the principle of the fermion spin superposition.The influence of the earth gravity on the spinor interference is considered.The results show that the Planck's constant H and the Newtonian gravitational constant G(or g) both are involved in the phase shift 6, which is independent of the neutron mass..

In this paper the Dirac's equation for the neutron in external magnetic fields is given. After decoupling into two equations of the simple spinors, the simplified equations are obtained by some reasonable approximations. The corresponding second order non-relativistic approximation, Green's function and single particle spectrum are derived. It is shown that, apart from easy solution, the precision of the simplified equation is sufficiently high, its applications are universal.