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91.
Valerii P. Matveenko E. P. Kligman M. A. Yurlov N. A. Yurlova 《Physical Mesomechanics》2012,15(3-4):190-199
The paper deals with optimization of dynamic characteristics of smart structures based on piezoelectric materials with external electric circuits comprising resistance, capacitance and inductance. The dynamic parameters to be optimized are resonance frequencies and damping properties. For numerical estimation of the dynamic characteristics of the model system, a natural vibration problem of an electroviscoelastic solid with differing external electric circuits is proposed. Model examples are given to demonstrate the efficiency of the natural vibration problem in finding dynamically optimum piezoelectric smart structures with external electric circuits. 相似文献
92.
L. I. Yudanova V. A. Logvinenko L. A. Sheludyakova N. F. Yudanov P. P. Semyannikov S. I. Kozhemyachenko I. V. Korol’kov N. A. Rudina A. V. Ishchenko 《Russian Journal of Inorganic Chemistry》2014,59(10):1180-1186
Comparison was made for the structural, IR spectral, and thermoanalytical characteristics of normal [M1(H2O)2(C4H2O4)](H2O) (M1 = Co(II) and Ni(II)) and acid maleates [M2(H2O)4(C4H3O4)2] (M2 = Mn(II), Fe(II), Co(II) and Ni(II)). Only structures of acid maleates contain intramolecular asymmetric hydrogen bond whose asymmetry increases in the series of transition metal salts. Thermal decomposition of Co(II), Ni(II) normal maleates, and Mn(II), Fe(II), Co(II), Ni(II) acid maleates proceeds in three stages. Onset decomposition temperatures for the first and second stages decreases in the series of normal maleates Co(II) ≥ Ni(II) and increases in the series of acid maleates Fe(II) < Co(II) < Ni(II) ≈ Mn(II). Onset temperature of the third stage decreases in the series of both normal maleates Co(II) > Ni(II) and acid maleates Mn(II) > Fe(II) > Co(II) > Ni(II). 相似文献
93.
A. V. Okotrub N. F. Yudanov V. M. Aleksashin L. G. Bulusheva O. A. Komarova U. O. Kostas P. N. Gevko N. V. Antyufeeva S. I. Il’chenko G. M. Gunyaev 《Polymer Science Series A》2007,49(6):702-707
Multi-walled carbon nanotubes synthesized by means of arc evaporation of graphite were used to prepare composites with a heat-resistant binder based on cyanoether. To increase the homogeneity of distribution of nanotubes in the polymer matrix, the carbon material was cleaned of graphite particles and amorphous carbon with a potassium permanganate solution in concentrated sulfuric acid. By means of X-ray photoelectron spectroscopy, it was shown that the proposed purification procedure leads to the grafting of oxygen-containing groups to the surface of carbon nanotubes. By means of differential scanning calorimetry, it was revealed that the oxide overcoat on the nanotube surface exerts an influence on the character of binder polymerization. The mechanical properties of a carbon-reinforced plastic with different nanotubes contents were measured. It was shown that the admixture of 0.25–0.50% carbon nanotubes improves the mechanical characteristics of carbon-reinforced plastics by 10–20%. 相似文献
94.
Yurii V. Larichev Boris L. Moroz Valerii I. Bukhtiyarov 《Applied Surface Science》2011,258(4):1541-1550
The electronic state of ruthenium in the supported Ru/EOx (EOx = MgO, Al2O3 or SiO2) catalysts prepared by with the use of Ru(OH)Cl3 or Ru(acac)3 (acac = acetylacetonate) and reduced with H2 at 723 K is characterized by X-ray photoelectron spectroscopy (XPS) in the Ru 3d, Cl 2p and O 1s regions. The influence of the final state effects (the differential charging and variation of the relaxation energy) on the binding energy (BE) of Ru 3d5/2 core level measured for supported Ru nanoparticles is estimated by comparison of the Fermi levels and the modified Auger parameters determined for the Ru/EOx samples with the corresponding characteristics of the bulk Ru metal. It is found that the negative shift of the Ru 3d5/2 peak which is observed in the spectrum of ruthenium deposited onto MgO (BE = 279.5-279.7 eV) with respect to that of Ru black (BE = 280.2 eV) or ruthenium supported on γ-Al2O3 and SiO2 (BE = 280.4 eV) is caused not by the transfer of electron density from basic sites of MgO, as considered earlier, but by the differential charging of the supported Ru particles compared with the support surface. Correction for the differential charging value reveals that the initial state energies of ruthenium in the Ru/EOx systems are almost identical (BE = 280.5 ± 0.1 eV) irrespectively of acid-base properties of the support, the mean size of supported Ru crystallites (within the range of 2-10 nm) and the surface Cl content. The results obtained suggest that the difference in ammonia synthesis activity between the Ru catalysts supported on MgO and on the acidic supports is accounted for by not different electronic state of ruthenium on the surface of these oxides but by some other reasons. 相似文献
95.
An important task for theory is the multi-scale modeling of catalytic properties of nanocrystallites with sizes ranging from
clusters of few metal atoms to particles consisting of 103–104 atoms. To explore catalytic properties of nanosized metal catalysts, we developed an approach based on three-dimensional
symmetric model clusters of 1–2 nm (~100 metal atoms) with fcc structure, terminated by low-index surfaces. With this modeling
technique one is able to describe at an accurate DFT level various catalytic and adsorption properties of metal nanoparticles
in quantitative agreement with experimental studies of model catalysts deposited on thin oxide films. Metal nanocrystallites
exhibit properties that can significantly vary with their size and shape. 相似文献
96.
An original approach is proposed to study the dipole–dipole interparticle interactions in dispersed magnets. It is the registration
and analysis of the noiselike ferromagnetic resonance fine structure, which is caused by the magnetic dipole–dipole interaction
between magnetic domains. The features of fine structure formation are discussed. The experimental examples of the possible
applications of the fine structure method are given.
Authors' address: Oleg N. Martyanov, Boreskov Institute of Catalysis, Russian Academy of Sciences, Prospekt Akademika Lavrentieva
5, Novosibirsk 630090, Russian Federation 相似文献
97.
A. I. Romanenko O. B. Anikeeva A. V. Okotrub L. G. Bulusheva N. F. Yudanov C. Dong Y. Ni 《Physics of the Solid State》2002,44(4):659-662
Bulk samples of oriented carbon nanotubes were prepared by electric arc evaporation of graphite in a helium environment. The temperature dependence of the conductivity σ(T), as well as the temperature and field dependences of the magnetic susceptibility χ(T, B) and magnetoresistance ρ(B, T), was measured for both the pristine and brominated samples. The pristine samples exhibit an anisotropy in the conductivity σ∥(T)/σ⊥>50, which disappears in the brominated samples. The χ(T, B) data were used to estimate the carrier concentration n 0 in the samples: n 0ini ~3×1010 cm?2 for the pristine sample, and n 0Br~1011 cm\t—2 for the brominated sample. Estimation of the total carrier concentration n=n e+n p from the data on ρ(B, T) yields n ini=4×1017 cm?3 (or 1.3×1010 cm?2) and n Br=2×1018 cm?3 (or 6.7×1010 cm?2). These estimates are in good agreement with one another and indicate an approximately fourfold increase in carrier concentration in samples after bromination. 相似文献
98.
N. F. Yudanov L. I. Chernyavskii V. I. Lisoivan I. I. Yakovlev 《Journal of Structural Chemistry》1988,29(3):412-418
Conclusion The results obtained in the present work show that the use of the method proposed in [3] to study the structure of intercalated compounds of graphite fluoride has made it possible to resolve in principle the question of the distribution of the C2FX layers along the z axis in these compounds and to determine the nature of the arrangement of the inserted molecules between the layers.In intercalated compounds of stage I with an expanded structure of the filled layer, the molecules of the inserted solvent are distributed chiefly in two layers between the C2Fx layers, whereas in the compounds with the simple structure they are distributed in one layer.In the intercalated compounds of stage II, the thickness of the unfilled layer is 6 Å, and the thickness of the filled layer coincides with the thickness of the layer in the corresponding inercalated compounds of stage I with the simple structure of the filled layer.The fluorine atoms in C2Fx are arranged symmetrically on each side of the carbon layer.In the intercalated compounds heated to a temperature of 200°C, the graphite fluoride layers form stacks with a distance of 6.0 Å between the layers.On the basis of the results obtained, it has been suggested that the most probable reason for the strong retention of the inserted component in the intercalated compounds of stage II is the paired linking of the edge sections of the C2Fx layers.Institute of Inorganic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 29, No. 3, pp. 78–83, May–June, 1988. 相似文献
99.
100.