多电子束契伦柯夫自由电子激光振荡器

我们对多电子束契伦柯夫自由电子激光进行了首次实验研究。280A,500kV的电子束被引入一多介质矩形谐振腔,在频率为33.4GHz处产生了1.7MW的契伦柯夫相干受激辐射。互作用效率为1.2％。     

Nitroazines. 20. Simple syntheses of nitropyrazolopyridines from aliphatic nitrosynthons and aminopyrazoles

Two variants of a synthesis for nitropyrazolopyridines from aminopyrazoles and two- or three-carbon nitrosynthons are examined.For Communication 19 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1560–1564, November, 1992.     

Inversion of the density gradient and the diffusion “gate” in isothermal mixing of gases

The stable quasistationary mixing of ternary gas mixtures in a system of two chambers connected by a capillary is described by a theoretical model which predicts the density distribution of the mixture along the length of the diffusion channel. It is demonstrated that inversion of the density gradient can occur due to a nonlinear concentration distribution of the heavy component in a diffusion “gate” effect. The results obtained using this model are compared with the experimental data. Zh. Tekh. Fiz. 68, 14–17 (May 1998)     

Distribution of silicon over sublattices in semiconducting A3B5 compounds

The stable site of Si substitutional impurities in GaAs and AlAs at T=0 K is determined on the basis of an analysis of the energy of solution of silicon, and of the energies of formation of intrinsic defects and the reaction energies of their interaction obtained by calculating the total energy of the disordered compounds. These calculations indicate that amphotericity and vacancies have an effect on the distribution of Si. At low Si concentrations, Si in GaAs is located on the sublattice of the group III element, and in AlAs, on the sublattice of the group V element. Fiz. Tverd. Tela (St. Petersburg) 39, 264–266 (February 1997)     

Existence and stability of periodic solutions for chains of connected oscillators

We consider a nonlinear system of difference equations. This system corresponds to chains of N symmetrically connected oscillators with sufficiently general type of connection, which includes, among others, local and global connection. We prove a theorem on the existence and stability of space-time periodic solutions of such systems for sufficiently small values of the parameter of connection ?.     

Quantum Key Distribution Using High-Dimensional Quantum Error-Avoiding Code

Using high-dimensional quantum error-avoiding code, we present two new quantum key distribution protocols over a collective noisy channel, i.e. six-photon and five-photon quantum error-avoiding codes. Compared with the previous protocols using four-photon and three-photon quantum error-avoiding code, the qubit efficiencies of the new protocols have increases of 16.67% and 5% respectively. In addition, the security of these protocols is analysed with a conclusion that the new protocols are much more secure than the four-photon and three-photon ones.