Nitrobenzene oxidation of fractions of cotton-plant dioxane lignin

Summary Analysis of the products of alkaline nitrobenzene oxidation of lignin fractions has confirmed their chemical inhomogeneity and has shown that in the various fractions the amounts of condensed syringly and guaiacyl structures differed markedly.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii No. 1, pp. 82–84, January–February, 1979.     

On Free Energies of the Ising Model on the Cayley Tree

We present, for the Ising model on the Cayley tree, some explicit formulae of the free energies (and entropies) according to boundary conditions (b.c.). They include translation-invariant, periodic, Dobrushin-like b.c., as well as those corresponding to (recently discovered) weakly periodic Gibbs states. The weakly periodic measures are defined through a partition of the Cayley tree that induces a 4-edge-coloring on that tree. We compute the density of each color. We use these densities for computations of free energies corresponding to a weakly periodic b.c.     

Two-photon-excited fluorescence in ultradisperse diamond powders

The spectra of two-photon-excited fluorescence in the near ultraviolet are studied in diamond powders prepared by detonation synthesis, with particle sizes of 20–40 Å. The spectra of ultradisperse diamond powders are compared with that of a diamond single crystal. It is shown that the proposed method can be used to detect ultradisperse diamonds in quantities as low as 10^?12 g.     

Two-photon-excited fluorescence in KTiOPO4 polycrystals

The spectra of two-photon-excited fluorescence in KTiOPO₄ were obtained at room temperature. A coppervapor laser was used as a source of excitation light and provided two emission lines (λ=510.6 and 578.2 nm). The laser operated at a high pulse-repetition rate (～ 10⁴ Hz) and featured a peak power of about 10⁴ W, average power of 1 W, and pulse duration of 20 ns. The fluorescence spectra of crystalline KTiOPO₄ are compared with the resonance fluorescence spectra of KTiOPO₄ at 4.2 K. The measured decay time of fluorescence was found to be less than 16 ns. The efficiency of conversion of the laser radiation to fluorescence was about 10^?10 under saturation conditions.     

Alkaloids of Gentiana olivieri

Summary The separation of the chloroform fraction of the combined alkaloids ofG. olivieri according to basicities (pH 6.0 and 4.0) has yielded gentioflavine, gentiananine, and the new base oliveramine, C₂₀H₂₀N₂O₄. On the basis of its UV, IR, NMR, and mass spectra structure (I) has been put forward as the most probable for it.Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 64–67, January–February, 1973.