Cation electron densities in the orthorhombic phase in YBa2Cu3O6+x ceramic

Donetsk Technical Physics Institute, Academy of Sciences of the Ukrainian SSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 4, pp. 12–16, July–August, 1990.     

Reactions of some chlorohydrins with uracils

Conclusions By the reactions of uracil and 6-methyluracil with chlorohydrins 3-(hydroxyalkyl)- and 1,3-bishydroxyalkyl-uracils were prepared, and their structures were proved.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1327–1329, June, 1968.We thank V. D. Kochkina and S. A. Flegontov for determining the IR spectra.     

New effect in near-field thermal emission

A near-field effect has been discovered experimentally in thermal radio emission of an absorbing dielectric medium. It is related to a specific character of the distribution of a quasistationary field component near a radiating surface. The effect consists of the fact that the effective depth of the received emission formation appears to be less than the skin-layer depth and depends on the size of the receiver antenna and its height above the surface. It can be considered as a new source of information about depth temperature distribution. A theory has been developed that allows for determining the relative contribution of wave and quasistationary components to the Plank emission received near the surface.     

Effects of a Quasi-Stationary Field in Contact Radiometry

We analyze theoretically the thermal radiation of an absorbing half-space, received by an antenna of an arbitrary size located at an arbitrary height above the half-space surface. It is shown that the measured power consists of quasi-stationary (near-field) and wave components. The relative contribution of each component depends on the antenna size and height. Conditions under which the near-field component is dominant are found. It is shown that the total power of the radiation received from a uniformly heated medium is entirely determined by the medium temperature and is independent of the antenna parameters. If the influence of the quasi-stationary field is strong, then the received radiation is formed in a layer whose effective depth is less than the skin-layer depth. This effect can be used for detection of the near-field component of thermal radiation.     

Highly anisotropic anomaly in the dispersion of the copper-oxygen bond-bending phonon in superconducting YBa2Cu3O7 from inelastic neutron scattering

Motivated by predictions of a substantial contribution of the "buckling" vibration of the CuO(2) layers to d-wave superconductivity in the cuprates, we have performed an inelastic neutron scattering study of this phonon in an array of untwinned crystals of YBa(2)Cu(3)O(7). The data reveal a pronounced softening of the phonon at the in-plane wave vector q=(0,0.3) upon cooling below ~105 K, but no corresponding anomaly at q=(0.3,0). Based on the observed in-plane anisotropy, we argue that the electron-phonon interaction responsible for this anomaly supports an electronic instability associated with a uniaxial charge-density modulation and does not mediate d-wave superconductivity.     

Synthesis and some chemical properties of 8-methyl-3-hydroxy-6-oxo-2H-3,4,5,6-tetrahydropyrimido [2,1-b][l,3]thiazines

Conclusions Pyrimidothiazines are converted to the corresponding 3-(thiiranyl-2'-methyl)-6-methyl-uracils on heating (170–200°C) in organic solvents.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1634–1636, July, 1986.     

Thermal Near Field and the Possibilities of Its Use for In-Depth Temperature Diagnostics of Media

We discover experimentally the effect of an electromagnetic thermal near field of a lossy medium. The effective depth d_eff of the layer in which the received signal is formed is found to be less than the skin-layer depth d_sk and is a function of the size D of the receiving antenna and its height h above the medium surface. The dependence d_eff(D,h) is obtained from measurements of the emission from a temperature-stratified water medium at a wavelength of 31 cm using a specially developed, electrically small antenna. The results of experimental studies of radiophysical parameters of the antenna are presented. We propose to use measurements of the dependence of the received emission on D and h as a new source of information on the in-depth temperature distribution. Methods for solving the corresponding inverse problems are developed, and the first results of retrieval of the subsurface temperature profile of a water medium are obtained.     

Synthesis and properties of pyrimidinylalkylsulfonamides 4. Reaction of the Na salt of p-toluenesulfonamide with mono-N-(ω-haloalkyl)uracils

Conclusions The direction of reaction and the composition and yields of products obtained by reaction of the Na salt of p-toluenesulfonamide with N-(-bromoalkyl)uracils depend primarily on the length of the alkyl chain in the latter: When the Na salt of p-toluenesulfonamide reacts with N-(-bromopropyl)-6-methyluracil, the latter undergoes intramolecular cyclization, whereas the Na salt of p-toluenesulfonamide undergoes intermolecular alkylation at the sulfonamide group on reaction with N-(-bromopentyl)-6-methyluracil. In analogous reactions, N-(-bromobutyl)uracils undergo both intramolecular cyclization, followed by opening of the oxazepine ring by nucleophilic reagents, and intermolecular alkylation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2079–2084, September, 1978.