[en] It is well known that a significant proportion of the rigorous results obtained in the framework of axiomatic quantum field theory is based on the use of the analytic properties of the scattering amplitude in the complex plane of the energy variable E. However, it is only for a restricted class of scattering processes and only for a restricted range of values of the square of the momentum transfer that one can prove analyticity of the amplitude in the entire complex E plane, except for cuts along the real axis. For other processes, which include, in particular, the practically very important process of nucleon-nucleon scattering, analyticity of the scattering amplitude in such a maximally large region cannot be proved for any values of the momentum transfer. In the general case of an arbitrary two-particle scattering process involving particles of nonzero mass only the following properties of analyticity of the amplitude with respect to the energy for fixed physical value of t have been proved: (a) the amplitude is analytic in the complete complex E plane except for the physical cuts and a certain region D in the neighborhood of the origin. The actual form of D is unknown - it is known only that it has a finite size (but, in general, this may be very large and increase with increasing t as |t|³); (b) the amplitude is analytic in some neighborhood (in general, arbitrarily small) of each physical point. It is shown that for an arbitrary two-particle scattering process one can, for any physical value of the momentum transfer, construct a function that is analytic in a maximally large region and simultaneously approximates with arbitrary good accuracy the scattering amplitude for physical values of the energy

[en] Bridge- and point-type junctions made of yttrium (YBaCuO) or bismuth (BiPbSnCaCuO) ceramic bars of 2 x 2 mm² or 2 x 1 mm² cross section are investigated. It is shown that a two-parametric family of stable states is harnessed in the junction, each state having its own specific R value

[en] It is shown that for arbitrary scattering processes of two particles and for arbitrary values of momentum transfer, the function can be constructed which is analytical in the largest possible domain and at the same time approximates the scattering amplitude for all physical energy values with arbitrary high precision

[en] The upper bounds on different integrals of a total cross section are derived in the analytical form. In particular, a strict evaluation of the high-energy part of the dispersion integral is obtained. The bounds obtained are intensified considerably when an experimentally observed small ratio of elastic-to-total cross section is taken into account. As the Froissart-Martin bound with account of that factor is improved approximately by a σsub(el)/σsub(t) multiplier a similar improvement will hold for the bounds on the integrals of a total cross section as well

[en] It is shown that the scattering amplitude analyticity in the whole E plane excluding a real axis can be actually Used for all the processes of two-particle scattering and for random physical values of a transferred momentum. For this purpose a modified delay amplitude, modified leading amplitude and modified ''physical'' amplitude have been constructed

[en] The rigorous lower bound for the elastic-to-total cross-section ratio is derived at finite energies in analytical form. The obtained bound allows one to make numerical estimates of total cross-section which are sufficiently close to corresponding experimental data. (author)

[en] Rigorous relations connecting the behaviour of real and imaginary parts of antisymmetric (symmetric) amplitude at arbitrary energies are obtained. Diverse versions of Pomaranchuk theorem and their generalization at finite energies follow from these relations. 24 refs. (author)

[en] The paper generalizes the Pomeranchuk theorem for finite energies. Restriction on the difference of Δσ identy sign σsub(+)-σsub(-) total cross-sections for the given restriction on the growth of a real part of fsub(α)(E) antisymmetric amplitude i.e. directly ''the Pomeranchuk theorem for finite energies has been obtained. Finite-energy analog of the Pomeranchuk inverse theory has been considered as well as restrictions on real and imaginary parts of fsub(s)(E) symmetric amplitude