Holographic Model of Exciton Condensation in a Double Monolayer Dirac Semimetal

JETP Letters - In this paper we consider holographic model of exciton condensation in double monolayer Dirac semimetal. Exciton is a bound state of an electron and a hole. Being Bose particles,...     

Plasmon–Magnon Interaction in the (Graphene–Antiferromagnetic Insulator) System

JETP Letters - Effect of plasmon–magnon interaction on the propagation of a hybrid wave along the graphene surface in the graphene–antiferromagnetic insulator system is studied. Three...     

Three-dimensional tomography in gas flow diagnostics in the presence of an opaque body

The possibility of tomographic reconstruction of the density distribution in a three-dimensional gas flow with a complex structure is considered. The effect of the presence of an opaque body on the reconstruction results is studied. Specific features of the inverse problem that are associated with practical realization of the experiment, namely, a small number of viewing angles and the presence of noise in projection data, are taken into account in numerical simulation. Institute of Theoretical and Applied Mechanics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 1, pp. 174–180, January–February, 1998.     

Spatial structure of the lower mode of ion-acoustic instability in the plasma of a high-current ion laser

The spatial structure of the lower mode of ion-acoustic instability in the plasma of the continuous discharge of a high-current argon ion laser is studied experimentally. The oscillations in the intensity of the spontaneous ArII line radiation from the plasma are recorded in different directions in cross sections perpen-dicular to the discharge axis. The power spectra of the integral projections of radiation are obtained and used to reconstruct the two-dimensional spatial structure of the mode, which is identified by using the available theoretical models.     

Electron-beam tomography of the density of a gas in hypersonic flow around objects

A procedure is developed for the tomographic reconstruction of the distribution of the gas density from measurements data on the attenuation of a sensing beam of fast electrons. The measurements and reconstruction are carried out for symmetrical and asymmetrical conical objects in a low-density hypersonic flow (M=21). Zh. Tekh. Fiz. 68, 125–133 (April 1998)     

Three-dimensional emission tomography of optically thick plasma for the known absorption

The three-dimensional emission tomography of a plasma partially absorbing intrinsic emission is studied. The distribution of local absorption coefficients is assumed to be known. To determine the distribution of local emission coefficients under the given conditions, the use of algebraic algorithms inverting the projection matrix constructed taking into account absorption is proposed. NDAT and NDFBP algorithms are developed, which are based on the expansion of the product of the operator of energy transport in an absorbing medium and the operator of the solution of the problem of emission tomography of a transparent plasma in a Neumann series. A numerical simulation is made, which shows that the emission field can be reconstructed with a reasonable accuracy for an optical thickness as high as 6–8.     

Investigation of the emission of photons induced in the volume reflection of 10-GeV positrons in a bent silicon single crystal

The emission of photons in the motion of a 10-GeV positron beam in bent silicon crystals has been experimentally investigated. The experimental data are compared with the theoretical calculations.     

Ring formation during the reaction of aromatic diamines with acetoacetic acid esters

It is shown that the reaction of aromatic o-diamines having a nitro group in the para position relative to one of the amino groups with acetoacetic esters under mild conditions gives arylaminocrotonates, which are isomerized to ketimines under the influence of acid, are cyclized to dihydro-1,5-benzodiazepinones on heating, and are converted to 1-isopropenylbenzimidazolones under more severe conditions. If the condensation of the nitrodiamine with the acetoacetic acid esters is carried out under severe conditions, the isomeric dihydro-1,5-benzodiazepinone is obtained. Splitting out of an alkylacetate ester to give the corresponding 2-methylbenzimidazole occurs in the condensation of various o-diamines with 2-alkylacetoacetic esters.