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I. A. Novakov D. V. Pyl’nov M. A. Vaniev A. V. Nistratov V. P. Medvedev E. V. Petrosyan 《Russian Journal of Applied Chemistry》2013,86(1):76-81
Rheokinetic studies of curing of oligodiene-urethane prepolymer with a hydroxyl-containing curing agent at the molar ratio NCO/OH = 1.0 were performed. In the initial step of curing, catalyltic formation of polydiene-urethane follows a second-order equation, whereas the urethane formation step is adequately described by a kinetic equation with an autoacceleration effect. 相似文献
3.
I. A. Novakov A. V. Nistratov D. V. Pyl’nov S. Yu. Gugina E. N. Titova 《Polymer Science Series D》2012,5(2):92-95
The results of investigations on the establishment of the interrelations between the foaming parameters and properties of
polydieneurethane foams are presented. It is shown that the combined application of tertiary amines and organotin compounds
as catalysts for urethane formation allows attainment of synchronization of kinetic parameters, which facilitates the production
of materials with a uniform fine meshed structure and improved physicomechanical properties. 相似文献
4.
A. A. Berlin I. A. Novakov A. Ya. Lyapunov A. V. Nistratov E. N. Titova L. S. Bekhli S. Yu. Gugina D. V. Pyl’nov 《Polymer Science Series D》2012,5(3):133-137
The results of an investigation of the influence of stillage residues of polyfluorinated alcoholtelomeres on the properties of polydienurethane compositions and elastomers based on them are presented. It is shown that such modification allows one to raise the sedimentation stability of the compositions and increase the characteristics of physicochemical and dynamic properties of elastomers. 相似文献
5.
I. A. Novakov A. V. Nistratov V. I. Frolova V. V. Klimov D. V. Pyl’nov S. Yu. Gugina E. N. Titova 《Polymer Science Series D》2012,5(2):96-101
The effect of the physicochemical structure of polymerizable compounds on the curing process, structure, and properties of
the materials based on liquid thiocols is studied. It is shown that the introduction of oligoacrylates in the amount of 2.5–10
vol % increases the extent of cross-linking, content of gel fraction, and stress-strain parameters of elastomers and leads
to smoothing of the material surface microrelief and decrease of the amount of micropores, which facilitates reduction in
swelling ofelastomers in aggressive media. 相似文献
6.
Self-injection length in La0.7Ca0.3MnO3-YBa2Cu3O7-δ ferromagnet-superconductor multilayer thin films
We have carried out extensive studies on the self-injection problem in barrierless heterojunctions between La0.7Ca0.3MnO3 (LCMO) and YBa2Cu3O7-δ (YBCO) thin films. The heterojunctions were formed in situ by sequentially growing LCMO and YBCO films on 〈100〉 LaAlO3 (LAO) substrate using a pulsed laser deposition (PLD) system. YBCO micro-bridges with 64 μm width were patterned both on
the LAO (control) and LCMO side of the substrate. Critical current, I
c, was measured at 77 K on both the control side as well as the LCMO side for different YBCO film thickness. It was observed
that while the control side showed a J
c of ∼ 2 × 106 A/cm2, the LCMO side showed about half the value for the same thickness (1800 ?). The difference in J
c indicates that a certain thickness of YBCO has become ‘effectively’ normal due to self-injection. From the measurement of
J
c at two different thicknesses (1800 ? and 1500 ?) of YBCO films both on the LAO as well as the LCMO side, the value of self-injection
length (at 77 K) was estimated to be ∼ 900 ?. To the authors’ best knowledge, this is the first time that self-injection length
has been quantified. A control experiment carried out with LaNiO3 deposited by PLD on YBCO did not show any evidence of self-injection. 相似文献
7.
Study of magnetoresistance and conductance of bicrystal grain boundary in La0.67Ba0.33MnO3 thin film
La0.67Ba0.33MnO3 (LBMO) thin film is deposited on a 36.7°C SrTiO3 bicrystal substrate using laser ablation technique. A microbridge is created across bicrystal grain boundary and its characteristics
are compared with a microbridge on the LBMO film having no grain boundary. Presence of grain boundary exhibits substantial
magnetoresistance ratio (MRR) in the low field and low temperature region. Bicrystal grain boundary contribution in MRR disappears
at temperature T>175 K. At low temperature, I-V characteristic of the microbridge across bicrystal grain boundary is nonlinear. Analysis of temperature dependence of dynamic
conductance-voltage characteristics of the bicrystal grain boundary indicates that at low temperatures (T<175 K) carrier transport across the grain boundary in LBMO film is dominated by inelastic tunneling via pairs of manganese
atoms and tunneling through disordered oxides. At higher temperatures (T>175 K), magnetic scattering process is dominating. Decrease of bicrystal grain boundary contribution in magnetoresistance
with the increase in temperature is due to enhanced spin-flip scattering process. 相似文献
8.
Molar extinction coefficients of some carbohydrates viz. l-arabinose (C5H10O5), d-glucose (C6H12O6), d-mannose (C6H12O6), d-galactose (C6H12O6), d(-) fructose (C6H12O6) and maltose (C12H24O12) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a
narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following a 4-parameter
polynomial. These extinction coefficients for different sugars having the same molecular formula have same values varying
within experimental uncertainty. Within concentration ranges studied, Beer-Lambert law is obeyed very well. 相似文献
9.
Mathias Kersemans Wim Van Paepegem Koen Van Den Abeele Lincy Pyl Filip Zastavnik Hugo Sol Joris Degrieck 《Ultrasonics》2014
The ultrasonic polar scan (UPS), either in transmission, reflection or backscatter mode, is a promising non-destructive testing technique for the characterization of composites, providing information about the mechanical anisotropy, the viscoelastic damping, the surface roughness, and more. At present, the technique is merely being used for qualitative purposes. The limited quantitative exploration and use of the technique can be primarily ascribed to limitations of current theoretical models as well as the difficulty to perform accurate, and more importantly, reproducible UPS experiments. Over the last years, we have identified several potential pitfalls in the experimental implementation of the technique which severely deteriorate the accurateness and reproducibility of a UPS. In this paper, we make an inventory of the most important difficulties, illustrate each of them by a real experiment and present a feasible mediation, either numerical or experimental in nature. Once the experimental set-up is fine-tuned to overcome these pitfalls, it is expected that the recording of high-level UPS experiments, in combination with numerical computations, will facilitate the technique to become a fully quantitative non-destructive characterization method. 相似文献
10.
Smagin N. V. Pyl’nov Yu. V. Preobrazhenski? V. L. Pernod P. 《Acoustical Physics》2009,55(4-5):657-664
Acoustical Physics - The potential of ultrasonic velocimetry and mapping for liquid flows in a model and real biological media is demonstrated experimentally and theoretically using the technique... 相似文献