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61.
The situation where a “nice” diffeomorphism f of a 3-manifold has a wildly embedded invariant surfaceM for which the restriction g = f| M : M → M is “nice” is considered. 相似文献
62.
T. G. Cherkasova I. Yu. Bagryanskaya N. V. Pervukhina N. V. Kurat’eva V. V. Medvedev E. S. Tatarinova E. V. Cherkasova 《Russian Journal of Inorganic Chemistry》2017,62(6):760-765
New double complexes [Co(DMSO)6][SiF6] ? 2H2O (I) and [Co(DMF)3(H2O)3][SiF6] ? DMF (II) have been synthesized and studied by IR spectroscopy and X-ray diffraction. Crystals of complex I belong to the tetragonal symmetry system, space group R3?, Z = 3, a = 11.8232(3) Å, c = 18.4699(5) Å, V = 2235.97(10) Å3, ρcalc = 1.573 g/cm3. Crystals of complex II are triclinic, space group P1?, Z = 2, a = 8.6264(4) Å, b = 10.1419(4) Å, c = 13.9657(6) Å, α = 100.847(2)°, β = 98.549(2)°, γ = 93.479(2)°, V = 1181.71(9) Å3, ρcalc = 1.539 g/cm3. 相似文献
63.
V. F. Medvedev L. P. Medvedeva 《Journal of Applied Mechanics and Technical Physics》1975,16(3):407-411
An equation is obtained to determine the coefficient of hydraulic drag of dilute emulsions by using the turbulent viscosity concept and the phenomenon of quenching turbulent pulsations. The results of the theory are compared with experiment. 相似文献
64.
Yitzhak Wolanov Ovadia Lev Andrei V. Churakov Alexander G. Medvedev Vladimir M. Novotortsev Petr V. Prikhodchenko 《Tetrahedron》2010,66(27-28):5130-5133
Hydrogen peroxide is one of the most versatile oxidation reagents, still it has not fully been exploited by synthetic chemists since anhydrous (let alone pure) hydrogen peroxide requires hazardous preparation protocols. We have recently reported on the crystallization of serine and other amino acid perhydrates, thus paving the way for a new method for laboratory-scale production of anhydrous hydrogen peroxide solutions. Serine is insoluble in most organic solvents (e.g., methanol, ethyl acetate, and methyl acetate) that readily dissolve hydrogen peroxide. Moreover, since the adduct of hydrogen peroxide and serine is unstable in these organic solvents, crystalline serine perhydrate readily decomposes to give anhydrous solutions of hydrogen peroxide and crystalline precipitate of the amino acid. This procedure can then yield an anhydrous hydrogen peroxide solution in a single step. Moreover, filtration of the amino acid, and room temperature evaporation of the volatile solvent (e.g., methyl acetate), yields over 99% hydrogen peroxide. 相似文献
65.
A. I. Maslii N. P. Poddubnyi A. Zh. Medvedev 《Russian Journal of Electrochemistry》2010,46(4):411-421
Using an extended dynamic model of liquid flow-through porous electrode (PE), the effect of kinetics of deposition of individual
components and conditions of potentiostatic electrolysis on the dynamics and final parameters (the cathodic deposit weight,
the ratio between the amounts of components, and the spatial distribution of components) of codeposition of two metals M1 and M2 is studied. An equipotential PE operating in the direct-flow mode in the absence of anodic dissolution of electronegative
component M2 is considered. The effects of concentration, exchange currents, a difference between the equilibrium potentials M1 and M2, a prescribed voltage on PE, and solution flow velocity and direction are analyzed. It is shown that, for this version of
codeposition of metals, the rates of M1 and M2 deposition averaged over the PE width are constant in time. However, this does not mean that their local deposition rates
are constant. The general tendency is that the metal deposition rate on the rear part of PE decreases with the time, whereas
the deposition rate on the frontal zone of PE, which is closer to the anode, increases. As a result, the final profiles for
M1 and M2, which are calculated for equal deposition times taking into account and ignoring the redistribution of current during the
deposition, differ essentially. 相似文献
66.
Churakov AV Prikhodchenko PV Lev O Medvedev AG Tripol'skaya TA Vener MV 《The Journal of chemical physics》2010,133(16):164506
The crystal structure of NH(4)(+)OOH(-) is determined from single-crystal x-ray data obtained at 150 K. The crystal belongs to the space group P2(1)/c and has four molecules in a unit cell. The structure consists of discrete NH(4)(+) and OOH(-) ions. The OOH(-) ions are linked by short hydrogen bonds (2.533 A?) to form parallel infinite chains. The ammonium ions form links between these chains (the N?O distances vary from 2.714 to 2.855 A?) giving a three-dimensional network. The harmonic IR spectrum and H-bond energies are computed at the Perdew-Burke-Ernzerhof (PBE)/6-31G(??) level with periodic boundary conditions. A detailed analysis of the shared (bridging) protons' dynamics is obtained from the CPMD simulations at different temperatures. PBE functional with plane-wave basis set (110 Ry) is used. At 10 K the shared proton sits near the oxygen atom, only a few proton jumps along the chain are detected at 70 K while at 270 K numerous proton jumps exist in the trajectory. The local-minimum structure of the space group Cc is localized. It appears as a result of proton transfer along a chain. This process is endothermic (~2?kJ/mol) and is described as P2(1)/c?2Cc. The computed IR spectrum at 10 K is close to the harmonic one, the numerous bands appear at 70 K while at 270 K it shows a very broad absorption band that covers frequencies from about 1000 to 3000?cm(-1). The advantages of the NH(4)(+)OOH(-) crystal as a promising model for the experimental and DFT based molecular dynamics simulation studies of proton transfer along the chain are discussed. 相似文献
67.
V.V. Politaev I.L. Shukaev V.A. Volotchaev B.S. Medvedev 《Journal of solid state chemistry》2010,183(3):684-580
A family of α-NaFeO2-type oxides NaxM(1+x)/3Sb(2−x)/3O2 (M=Ni, Co, Zn, Mg; x≈0.8 or 0.9) has been prepared by solid state reactions and characterized by powder XRD. At x=1, ordering occurs with tripling the unit cells and formula units. The powder patterns for Na3M2SbO6 (M=Ni, Co) comply with both trigonal P3112 cell and monoclinic C2/m cell. The Ni compound exhibits also a series of extremely weak reflections (I<0.3%) that need doubling of the c axis, and the final cell is C2/c, a=5.3048(3), b=9.1879(4), c=10.8356(7), β=99.390(5). These ambiguities are explained by stacking faults. The compounds absorb atmospheric moisture with c-axis expansion up to 29%. A delafossite-related superlattice Ag3Co2SbO6 has been prepared by ion exchange and refined: P3112, a=5.3842(2), c=18.6613(10). Ionic conductivity of the Na0.8Ni0.6Sb0.4O2 ceramics, 0.4 S/m at 300 °C, is greater than reported previously, presumably owing to the grain orientation produced by hot pressing. 相似文献
68.
69.
Yu. M. Nikolaenko Yu. E. Kuzovlev Yu. V. Medvedev N. I. Mezin A. N. Bondarchuk A. B. Glot 《Physics of the Solid State》2011,53(11):2220-2226
The electrical characteristics of strontium-doped indium oxide have been experimentally investigated in the case of deviations
from the stoichiometric composition with respect to oxygen. Doping considerably decreases the electrical conductivity of In2O3 and makes it extremely highly sensitive to variations in the oxygen content. A small oxygen deficiency of the samples corresponds
to the high-resistance state, which is formed as a result of the decrease in the concentration of charge carriers and the
transparency of potential barriers at the grain boundaries. It has been found that the oxygen deficiency in In2O3 − δ: Sr restores a high n-type electrical conductivity, which is consistent with the concepts of oxygen vacancies as shallow donors. For a sufficient
oxygen deficiency, the potential barriers do not manifest themselves; however, as the oxygen content increases, there arises
a potential relief that leads to a set of remarkable effects: the specific nonlinearity and hysteresis of the current-voltage
characteristic, which are caused by the tunneling transparent potential barriers; an increase in the permittivity to 13.3
at a frequency of 105 Hz and at a temperature T = 77 K; and the temperature anomalies of the measured parameters, which are associated with the topological phase transition
to a spatially inhomogeneous conductance of the samples. It has been revealed that, for small deviations from the stoichiometric
composition with respect to oxygen, not only the active component but also the capacitive component of the conductance of
In2O3 − δ: Sr exhibit a sensitivity to the pressure and composition of the gas medium. 相似文献
70.
A.A. Pospelov V.B. Nalbandyan E.I. Serikova B.S. Medvedev M.A. Evstigneeva E.V. Ni V.V. Lukov 《Solid State Sciences》2011,13(11):1931-1937
A new compound, LiMn2+Mn3+TeO6, was prepared by solid-state reactions and characterized by powder X-ray diffraction, redox titration, conductivity, magnetic measurements and cycling behaviour in an electrochemical cell with Li counter electrode. It is triclinic, P1, a = 5.1077(1), b = 8.5707(1), c = 5.0589(1), α = 92.515(1)°, β = 92.092(2)°, γ = 89.818(2)°, Z = 2. The structure is based on strongly distorted hexagonal close packing of oxygen anions with cations occupying octahedral voids and represents the ordered variant of orthorhombic Li2TiTeO6 structure, derived from LiSbO3. TeO6 octahedra are almost regular but all four independent MnO6 octahedra display severe distortions. Room-temperature conductivity is unexpectedly low for a mixed-valence compound, 2 × 10−7 S/cm. Together with the observed antiferromagnetic exchange interaction, this is a prerequisite for the colossal magnetoresistance effect. The unit cell volumes of LiMn2TeO6, LiSbO3, Li2M4+TeO6 and LiMM′XO6 series (a total of 21 compounds) correlate well with average cationic radii, but LiMn2SbO6 deviates considerably, and its preparation could not be reproduced. 相似文献