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891.
We review and pay tribute to a result on convergent systems by the Russian mathematician Boris Pavlovich Demidovich. In a sense, Demidovich's approach forms a prelude to a field which is now called incremental stability of dynamical systems. Developments on incremental stability are reviewed from a historical perspective. 相似文献
892.
Conclusions A method of analyzing the process of spinning PCA yarns from the melt has been proposed.The region of stable spinning of PCA melts has been determined, with the objective of preparing yarns having a high uniformity in diameter along their length.Translated from Khimicheskie Volokna, No. 2, pp. 22–23, March–April, 1987. 相似文献
893.
894.
The stress at the boundary between nonmetallic oxide inclusions and the matrix may be calculated, for different loads, by
simulation of the system consisting of the matrix and inclusions. On that basis, the nonmetallic inclusions may be ranked
in terms of the risk of contact-fatigue defects. The phase composition and geometry of the nonmetallic inclusions in rail
steel are determined by the reduction of the rail steel and are extremely important for high rail performance. 相似文献
895.
The field electron emission from the surface of an iridium point emitter covered by a monolayer graphene film has been studied.
An analysis of the field emission images showed that electron emission takes place at the boundaries between graphene islands
with dimensions up to several dozen nanometers. Intercalation of alkali metal (cesium) atoms under the graphene film decreases
the work function of the emitter but does not change the image. Field ion desorption images obtained in the fields where the
surface diffusion of Cs atoms is impossible reveal the presence of a submonolayer concentration of cesium at the defects representing
graphene island contacts. 相似文献
896.
Al.?A.?PavlovEmail author A.?A.?Pavlov P.?A.?Pavlov A.?N.?Tsarkov O.?V.?Khoruzhenko 《Measurement Techniques》2011,53(11):1233-1235
A method of detection of single and double errors in devices used for storage and transmission of information in computerized
measurement equipment systems is proposed. 相似文献
897.
898.
O. M. Pavleino V. A. Pavlov M. A. Pavleino 《Surface Engineering and Applied Electrochemistry》2011,47(4):362-369
A numerical calculation of the pulsed heating of electrical contacts in a wide temperature range up to the melting point is
carried out on the basis of experimental oscillograms of the electrode voltage and current. The change in the radius of the
contact spot is determined taking into account the softening of the material. It is shown that even a slight spreading of
the spot can lead to a significant decrease in the contact temperature. The dynamics of the heating of the contact area are
analyzed, and the distributions of the temperature and heat flows are plotted. 相似文献
899.
A. V. Ershov I. A. Chugrov D. I. Tetelbaum A. I. Mashin D. A. Pavlov A. V. Nezhdanov A. I. Bobrov D. A. Grachev 《Semiconductors》2013,47(4):481-486
The alternate vacuum evaporation of SiO and SiO2 from separate sources is used to produce amorphous a-SiO x /SiO2 multilayer nanoperiodic structures with periods of 5–10 nm and a number of layers of up to 64. The effect of annealing at temperatures T a = 500–1100°C on the structural and optical properties of the nanostructures is studied. The results of transmission electron microscopy of the samples annealed at 1100°C indicate the annealing-induced formation of vertically ordered quasiperiodic arrays of Si nanocrystals, whose dimensions are comparable to the a-SiO x -layer thickness in the initial nanostructures. The nanostructures annealed at 1100°C exhibit size-dependent photoluminescence in the wavelength range 750–830 nm corresponding to Si nanocrystals. The data on infrared absorption and Raman scattering show that the thermal evolution of structural and phase state of the SiO x layers with increasing annealing temperature proceeds through the formation of amorphous Si nanoinclusions with the subsequent formation and growth of Si nanocrystals. 相似文献
900.
Cristina MM Alfaia Mrio AG Quaresma Matilde LF Castro Susana IV Martins Ana PV Portugal Carlos MGA Fontes Rui JB Bessa Jos AM Prates 《Journal of the science of food and agriculture》2006,86(13):2196-2205
This paper describes the fatty acid composition, including the isomeric distribution of conjugated linoleic acid (CLA), total lipids and cholesterol in longissimus dorsi (LD) and semitendinosus (ST) muscles of Mertolenga beef from young bulls reared according to Protected Designation of Origin (PDO) specifications. Mertolenga purebred young bulls (n = 30) were raised in a semi‐extensive production system, including a finishing period on concentrate feeds for the last 5 or 3 months (October and June samplings, respectively). Mertolenga‐PDO beef showed seasonal changes in the levels of some fatty acids (including the predominant 18:2n‐6), sums of trans fatty acids and n‐3 polyunsaturated fatty acids, some CLA isomers (t11,t13, t11,c13 and t10,c12), sums of geometric groups of CLA isomers and total cholesterol. In addition, significant differences were obtained between LD and ST muscles for most of the analysed parameters. From a nutritional perspective, beef‐PDO from June seems to be more healthful than that from October as a consequence of its lower n‐6/n‐3 ratio. Moreover, the results suggest that the polyunsaturated fatty acid/saturated fatty acid ratio in the ST muscle is consistently above the recommended guideline for human diets, although the values were below that guideline for the LD muscle. Taken together, the data indicate that, although the finishing period of Mertolengo young bulls on concentrate attenuates most of the beneficial grass effects on meat fat throughout the year, beef‐PDO from late spring is of greater nutritional value than that from early autumn. Copyright © 2006 Society of Chemical Industry 相似文献