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11.
A.A. FilaretovM.G. Zhizhin L.N. KomissarovaV.P. Danilov V.V. ChernyshevB.I. Lazoryak 《Journal of solid state chemistry》2002,166(2):362-368
A new ammonium indium phosphate (NH4)In(OH)PO4 was prepared by hydrothermal reaction in the In2O3-NH4H2PO4-NH3/OH system (T=200°C, autogenous pressure, 7 days). The formula (NH4)In(OH)PO4 was determined on the basis of chemical and thermal analysis (TG/DSC), X-ray powder diffraction and IR-spectroscopy. (NH4)In(OH)PO4 crystallizes in the tetragonal system with space group P43212 (No. 96); a=9.4232(1) Å, c=11.1766(1) Å, V=992.45(2) Å3; Z=8. The crystal structure was refined by the Rietveld method (Rw=6.35%, Rp=5.10%). The second-harmonic generation study confirmed that structure of (NH4)In(OH)PO4 does not have a center of symmetry. The cis-InO4(OH)2 octahedra form helical chains, parallel to the c-axis. The In-O-In bonds are nearly equidistant. The chains are interconnected by phosphate tetrahedra and create tunnels containing the NH4+ ions along the c-axis. (NH4)In(OH)PO4 is isostructural with RbIn(OH)PO4. 相似文献
12.
Danilov A. I. Molodkina E. B. Polukarov Yu. M. 《Russian Journal of Electrochemistry》2004,40(6):597-603
The formation of a copper adatom layer on polycrystalline platinum in a copper sulfate solution is studied by cyclic voltammetry in different cycling ranges at 0.1 V s–1. The copper adatom deposition kinetics is controlled by the following factors. The substrate's top layer structure during the oxygen exit onto the surface may be unstable at anodic limits E
a = 0.90–1.35 V. The concentration of copper oxides (active centers) may be higher at E
a = 0.8–0.95 V. The balance between different adsorption sites differs in different cycling conditions. Of importance is the number of complexes Oss–Pt
n
–SO4 and Oss–Pt
n
–Oc, where Oss is subsurface oxygen and Oc is chemisorbed oxygen. 相似文献
13.
Danilov A. I. Molodkina E. B. Polukarov Yu. M. 《Russian Journal of Electrochemistry》2002,38(7):732-742
Initial stages of copper electrocrystallization on glassy carbon from sulfuric acid electrolytes of pH 0.3 and 3.7 are studied by the cyclic voltammetry method on rotating and stationary ring–disk electrode. The rate of nucleation and growth of a metallic phase of copper in a 0.5 M Na2SO4 + 0.01 CuSO4 (pH 3.7) solution is marginally higher than in a 0.5 M H2SO4 + 0.01 M CuSO4 acid electrolyte (pH 0.3). Regularities governing the multistage discharge of copper ions, the formation of the new phase nuclei, and the deposit dissolution are analyzed. No copper adlayers form on glassy carbon at potentials more positive than the equilibrium potential of a reversible copper electrode, the copper nucleation occurs via the Volmer–Weber mechanism. The oxygen-containing surface groups of glassy carbon (quinone–hydroquinone, carbonyl, etc.) are probably active centers for the discharge of copper ions and the nucleation of the new phase. The results of the study are compared with the data on the kinetics of copper electrocrystallization on a platinum electrode. 相似文献
14.
V. A. Kuprievich V. I. Danilov O. V. Shramko 《Theoretical and Experimental Chemistry》1966,2(6):535-539
The self-consistent field (SCF) method is used in the semiempirical approximation (SA) with allowance for singly excited configurations to derive the ground state and singlet excited states for five nucleic acid bases (NAB). Empirical values are used for the nondiagonal elements of the matrix for the two-electron Coulomb integrals. The methyl group in thymine is allowed for via an induction model. Theoretical values are given for the energies of the first four electronic transitions for each base. The locations of these agree well with spectroscopic data. The energies of the first two transitions in adenine are found to be very similar when allowance is made for configuration interaction, so the first absorption band of adenine arises from overlap of two transitions. 相似文献
15.
The principal problems of quasi-two-dimensional (Q2-D) hydrodynamics are discussed. Accounting for Q2-D flow vertical structure is shown to eliminate "genetic" defects of the formal 2-D idealization of 3-D Navier-Stokes equations and allows under certain conditions to formulate corrected 2-D motion equations which adequately describe real hydrodynamic processes. The applicability of the approach is directly verified in laboratory experiments. Special attention is paid to the problem of 2-D turbulence. Its simulation on the basis of ordinary 2-D equations is unjustified because of the absence of the external Kolmogorov dissipation scale and reverse spectral energy flux. An alternative approach allows one to introduce the natural external scale of 2-D turbulence which depends only on physical properties of the system under consideration and to formulate the conditions under which the large scale vortex dynamics is expected to be universal at large Reynolds number, i.e., to be independent on the size and form of integration domain and lateral boundary conditions. 相似文献
16.
I. I. Perepechko V. A. Danilov V. V. Nizhegorodov 《Mechanics of Composite Materials》1996,32(4):316-320
Results are presented from measurements of the velocity of longitudinal and shear elastic waves (f=5 MHz) in ÉD-20 epoxy resin, at temperatures from 4.2 to 293 K. These data were used to calculate the moduli of elasticity E and G. Also, the moduli E (f=250 Hz) and G (f=2 Hz) of the ÉD-20 resin were measured directly. The calculated velocities of the low-frequency elastic waves ct=(E/p)1/2 and ct=(G/p)1/2 (where p is the density) were compared with the results from the ultrasonic measurements. The frequency dependence of elastic-wave velocity in the epoxy resin was evaluated. It was found that when the frequency was varied by four orders of magnitude, the dispersion of longitudinal-wave velocity was 18% at 4.2 K and 39% at 293 K. A quantitative criterion is proposed for estimation of the dispersion of sonic velocity from the results of measurements at any two frequencies. It was established that the sonic velocity at low temperatures varies linearly with the temperature, and in the case of longitudinal waves changes from cl-3360 m/sec at 4.2 K to 2820 m/sec at 293 K. The shear-wave velocity changes from ct=1630 m/sec at 5 K to 1340 m/sec at 293 K. The values of the dynamic Young's modulus E and shear modulus G at 4.2 K are 8.6 and 3.2 GPa, respectively. On a plot of c=f(T) for ED-20, a transition is observed at 180 K, due to reorientational rotation of methyl groups. The activation energy of the relaxation process is 3.6 kcal/mole. Large values are obtained for the dispersion of the dynamic modulus E:37.8% at 4.2 K and 93% at 293 K.Paper presented at 9th International Conference on the Mechanics of Composite Materials Riga, October, 1995.Moscow State Academy of Automotive Vehicle and Tractor Machinery Construction, Russia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 32, No. 4, pp. 460–466, July–August, 1996. 相似文献
17.
A. A. Shcherbakov I. P. Danilov V. A. Sazhin V. I. Petrov 《Theoretical and Experimental Chemistry》1993,28(4):277-279
An investigation of the hydration and amphiphilic properties of the piracetam and pramiracetam molecules has been conducted by theoretical conformational analysis and the Monte Carlo method; their localization and orientation at the water-lipophilic medium interface have been determined, which made it possible to explain the characteristics of the pharmacological action of the drugs.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 4, pp. 355–358, July–August, 1992. 相似文献
18.
M. Baru A. Danilov I. Vagenina E. Gorbunova S. Moshnikov L. Mustaeva V. Cherskii 《Chromatographia》1997,45(1):351-354
Summary The design of new dynamic, axial-compression columns with a system for continous packed bed adjustment and monitoring of the
floating adapter position is described. The columns are meant for liquid chromatography at low pressures (up to 8 bar) in
aqueous and organic media with stationary phases of all types. The columns have adapter position pickups for continuous automatic
monitoring of the bed height (original “swellographic” monitoring). The column described with gas pressurisation was tested
with soft Sephadex G-10 and G-25. In spite of the reduction in external porosity there was no dramatic increase in back-pressure.
The column proved to provide long-term stability of the packed bed and improvement in resolution.
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996 相似文献
19.
S. B. Denisova E. G. Galkin V. T. Danilov Yu. I. Murinov 《Chemistry of Natural Compounds》2003,39(3):237-239
Simple sugars were isolated from the ethanol extract of Glycyrrhiza glabra L. root. The component composition of the carbohydrate fraction was established using GC-MS (gas-chromatographic separation and mass-spectrometric analysis). 相似文献
20.
Danilov A. I. Molodkina E. B. Polukarov Yu. M. 《Russian Journal of Electrochemistry》2004,40(6):585-596
The oxidation of polycrystalline platinum in 0.5 M H2SO4 is studied by cyclic voltammetry at potential scan rates of 5–500 mV s–1 while varying the potential cycling range. The scheme, which is proposed for explaining the observed acceleration and deceleration of oxygen sorption at 0.75–1.0 V, accounts for the presence of oxygen in the subsurface layers of platinum (Oss) and the formation of a barrier layer comprising complexes Oss–Pt
n
–SO4. Cycling platinum secures certain steady-state contents of Oss at 0.01–1.35 V. In an anodic scan, Oss accumulates at E > 0.85 V (slow post-electrochemical stage) due to exchange of platinum and oxygen atom sites. In a cathodic scan, the desorption of most oxygen gives way to the adsorption of anions, which prevent residual Oss from appearing on the surface. The residual Oss disappears at E < 0.1 V after a sufficiently complete desorption of anions and the destruction of stable complexes Oss–Pt
n
–SO4. Varying the potential cyclic limit leads, after a delay, to other steady-state Oss contents. 相似文献