Table of contents

In the present paper we discuss various aspects of the 't Hooft model for two-dimensional QCD in the limit of an infinite number of colors in the Coulomb gauge. The properties of mesonic excitations are addressed, with special attention paid to the pionic one. The twofold role of the pion is discussed: being a genuine q state it is also a Goldstone boson of two-dimensional QCD. In particular, it is demonstrated explicitly how the soft-pion theorems are satisfied. It is pointed out that the Coulomb-gauge choice seems to be indispensable in studies of hadronic observables with the pions involved.

The current methods of synthesis and investigation of carbon nanotubes are reviewed. The interconnection between structural peculiarities and electronic characteristics of carbon nanotubes has been studied. The recently developed methods of growth of similar nanotubes with pre-assigned characteristics are described. The development of these methods offers the possibility of mass production and application of relevant devices. The phenomenon of electron field emission from carbon nanotubes and possibilities of its usage in flat panel displays, gas discharge devices, etc. is analyzed. Prospects and real achievements in the area of application of nanotubes as cold electron emission sources are discussed.

It is argued that preconditions currently exist for more actively studying the possibility of detecting cosmic rays of superhigh energy (10²¹–10²³ eV) by observing radio emission from a cascade shower. To illustrate this point, major results from the initial period of research (1961–1980) are briefly reviewed, problems unresolved at that time are pointed out, and subsequent advances that have stimulated further progress in this area are described.