On the flows of perfect dilatant isotropic media

Equations determining potential and shear-free flows of perfect isotropic dilatant media are considered.     

Doppeloktaeder-Cluster [V2O9] in der Kristallstruktur von Vanadium(III)-diphosphat,V4(P2O7)3

Double-Octahedra Clusters [V₂O₉] in the Crystal Structure of Vanadium (III) Diphosphate, V₄(P₂O₇)₃ . As the first example for M^III diphosphates the crystal structure of V₄(P₂O₇)₃ (“ I ”) has been determined by means of X-ray diffraction of single crystals. I – according to [7] obtainable by thermal interaction of V₂O₅, H₃PO₃, and H₃PO₄ – crystallizes orthorhombically (data see above); in the unit cell two kinds of isolated doubleoctahedra (clusters) [V₂O₉], having the symmetry C_s, exist. Due to a mutual face-connection of the octahedra, within these clusters relatively short V–V distances are resulting: 2.774(8) and 3.026(7) Å. The diphosphate anions, O₃POPO₃^4? (three kinds; each having the symmetry C_s and staggered conformation), exhibit POP bond angles of 170°, being remarkably large for non-centrosymmetry. Because of the [M₂^IIIO₉] clusters in I , and also in the isostructural diphosphates Cr₄(P₂O₇)₃ and Fe₄(P₂O₇₃), magnetic investigations seem to be challenged.     

Intramolecular interactions and nature of the lowest electronically excited states in compounds modeling the structural unit of lignin. II. Phenolate anions

Quantum-chemical calculations of the electronic structures of the phenolate ions of compounds modeling lignin in the ground and electronically excited states have been made by the CNDO/S method. The intramolecular electron donor-acceptor interactions in the phenolate anion on excitation and the nature of the lowest electronically excited states are discussed on the basis of the results obtained.Siberian Scientific-Research Institute of Pulp and Board, Bratsk. A. A. Zhdanov Irkutsk State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 275–282, March–April, 1988.     

Preparation ofγ-butyrolactones by oxidation of monofunctional tetrahydrofuran derivatives

Conclusions The major products in the oxygen-oxidation of tetrahydrofurfuryl alcohol, its esters, and an ester of 2-tetrahydrofurancarboxylic acid are -butyrolactone and the corresponding -substituted -butyrolactone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 577–579, March, 1972.     

Structural studies of nickel-based Raney catalysts

Electron microscopy and Mössbauer spectroscopy studies of nickel-based Raney catalysts have revealed that the catalysts are formed through the successive aggregation of their structural elements. Catalyst particles are covered by a thin layer of nickel oxide.

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Interphase interactions in a Pd-GaAs system and their effect on electrical properties of schottky-barrier structures I. effect of heat treatment on characteristics of GaAs-Pd/Ni contacts

The electrical characteristics of surface-barrier GaAs-Pd/Ni structures and the physicochemical interaction processes at the metal-semiconductor boundary were comprehensively investigated in relation to heat treatment in various atmospheres. X-Ray structural analysis showed that in the investigated system metallurgical reactions begin at 300–350C: Unstable intermediate phases (presumably Pd₂Ga) are formed. At 400–550C all the palladium is converted to the bound state and the intermetallic compound PdGa is formed. The phase changes have no significant effect on the properties of diode structures fired in a hydrogen atmosphere. Heating in vacuum leads to degradation of the contact parameters at 300C or more. This effect is attributed to penetration of oxygen to the interface during formation of the intermediate phases.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 3–7, April, 1981     

Phosphor for the Near-IR and Short-Wave IR Ranges Based on a Garnet Structured Cubic Modification of Lithium–Lanthanum Niobate

Physics of the Solid State - Cubic garnets activated by neodymium and holmium, Li6CaLa2Nb2O12:Nd3+,Ho3+, were obtained by solid-state method. The main regularities of changes in the luminescence...     

Reconstruction of the hologram structure from a digitally recorded Fourier specklegram

Optics and Spectroscopy - The possibilities of reconstructing the hologram structure and image from a digitally recorded Fourier specklegram without reference beam have been considered. The...     

Hybrid Extensions of the Minimal Logic

Siberian Mathematical Journal - We consider some extensions of Johansson’s minimal logic J. Hybrid logics extend the intersection of the intuitionistic logic Int and the negative...