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61.
Khoroshavin L. B. Golovina T. M. Bobrov E. V. Vol'kinshtein M. Ya. 《Refractories and Industrial Ceramics》2002,43(5-6):206-208
Results of a study of chromite dunites with different concentrations of chromite — from 10 to 20% Cr2O3 — are reported. Thermomechanical properties of control specimens are determined. Chromite dunites require precalcination for their use in the manufacture of forsterite-chromite components for thermal power units of ferrous and, especially, nonferrous metallurgy. 相似文献
62.
E. I. Kuznetsova Yu. V. Blinova S. V. Sudareva T. P. Krinitsina I. B. Bobylev E. P. Romanov 《The Physics of Metals and Metallography》2006,102(2):213-220
Electron and polarized-light optical microscopy have been used to study the spinodal decomposition of the YBa2Cu3O7?δ compound depending on the oxygen content. Experimental data reported indicate that whatever the state —initial or preliminarily aged at a high temperature—of the YBa2Cu3O7?δ (δ ≈ 0.2 and 0.4) nonstoichiometric oxide, it undergoes natural aging typical of metallic alloys. 相似文献
63.
XU Tao GAO Huawei LIU Jianhua YU Cuiyan 《稀有金属(英文版)》2007,26(4):398-402
The effect of ultrasonic vibration on the dechromisation corrosion of a CuCr alloy in HC1 solution was studied and the corrosion mechanisms were analyzed. It is found that ultlasonic vibration reduces the dechromisation incubation time, accelerates the dechromisafion corrosion rate, decreases the temperature and concentration of HC1 solution, and when the dechromisation occurs it seriously weakens the microstmcture of dechromisation layer. It is concluded that ultrasonic vibration can accelerate destruction of the passivation film on the Cr surface and increase the activities of Cl^- and Cr. 相似文献
64.
E. I. Kuznetsova S. V. Sudareva Yu. V. Blinova T. P. Krinitsina E. P. Romanov 《The Physics of Metals and Metallography》2006,102(2):221-225
Experimental results are presented on the phenomenon of recovery (characteristic of aging metallic alloys) in single crystals of nonstoichiometric oxides YBa2Cu3O~6.6 and EuBa2Cu3O~6.8. After single low-temperature and high-temperature annealings (200 and 300°C), all signs of spinodal decomposition in these single crystals were found; after double heat treatment (200°C + 300°C), the restoration of structure inherent in the initial state (antiphase domains of twin orientation) occurred. 相似文献
65.
K. I. Shein I. R. Shein N. I. Medvedeva E. V. Shalaeva M. V. Kuznetsov A. L. Ivanovskii 《The Physics of Metals and Metallography》2006,102(6):604-610
A comparative analysis of the atomic relaxation and electronic structure of niobium (100) and (110) surfaces has been carried out using the VASP-PAW method. The relaxation-induced changes in interlayer spacings of surface layers demonstrate an oscillating behavior but they substantially differ for the two analyzed surfaces; namely for the (110) surface with the closest atomic packing two outermost surface layers are contracted by 4.3% and the relaxation becomes noticeable for three outer layers, while for the more “open” (100) surface these quantities equal 13.1 and six layers, respectively. An analysis of the layer-by-layer distribution of the densities of states, spatial distribution of the charge density, and densities of states at the Fermi level indicates that the most considerable changes near Fermi level take place for (100) surface. 相似文献
66.
Yu. N. Dragoshanskii V. V. Shulika A. P. Potapov O. F. Denisov 《The Physics of Metals and Metallography》2006,101(6):519-523
It has been shown that the formation of nitride-oxide magnetically active electrically insulating coatings on ribbons of iron-based soft magnetic alloys using the method of ion-plasma deposition and subsequent magnetic annealing in an ac magnetic field leads to a substantial improvement of their static and dynamic magnetic properties. 相似文献
67.
A. V. Makarov R. A. Savrai V. M. Schastlivtsev T. I. Tabatchikova L. Yu. Egorova 《The Physics of Metals and Metallography》2007,104(5):522-534
The hardness and mechanical properties of the U10 steel (1.03 wt % C) with pearlite structures that were formed by isothermal decomposition at temperatures of 650°C (coarse-lamellar pearlite) and 500°C (fine-lamellar pearlite) as well as upon subsequent annealing of fine-lamellar pearlite at a temperature of 650°C for 10–300 min have been studied upon tensile tests. Fractures of the steel with different types of pearlite structure have been examined using scanning electron microscopy. The interrelation between the mechanical properties and the structural features and character of fracture has been analyzed for this steel with pearlite structures differing in the dispersity, morphology, and defect structure of cementite, and in the levels of solid-solution strengthening and microdistortions of the ferrite-constituent lattice. 相似文献
68.
L. M. Voronova M. V. Degtyarev T. I. Chashchukhina 《The Physics of Metals and Metallography》2007,104(3):262-273
Grain growth has been investigated during heating of pure single-phase iron with an ultra-dispersed structure of different types under conditions which exclude retardation by impurity atoms or by dispersed particles. The rate of growth mainly depends on the type of boundaries formed in this structure during a preliminary treatment, which determines the different kinetics of primary recrystallization. The thermal stability of submicrocrystalline (SMC) structure increases with increasing degree of deformation. In contrast to the materials with an impurity and carbide retardation, in pure iron an intermediate annealing of the SMC structure, which usually leads during low-temperature recrystallization to the formation of a honeycomb structure, does not influence thermal stability. The formation of thermally activated centers of recrystallization has been found to occur during heating of iron with a uniform isotropic SMC structure at the temperature of the onset of the recrystallization of moderately deformed iron. The formation of a honeycomb structure does not lead to a considerable reduction in the accumulated strain energy, and, during further heating, thermally activated nuclei of recrystallization are formed. 相似文献
69.
A. I. Ponomarev V. I. Tsidilkovski K. R. Krylov T. B. Charikova A. A. Lakhtin L. I. Leonyuk 《Journal of Superconductivity》1996,9(1):27-32
The anisotropy of the resistivity and thermoelectric power (TEP)S of Nd1.85Ce0.15CuO4– single crystal (T
c
=17 K) has been investigated. In the temperature rangeT
c
<T<300 K the ratio
c/ab104 and the dependences
ab
(T) and
c
(T) change from quadratic to linear atT200 K. The dependencesS
ab
(T) andS
c
(T) reach a maximum atT>T
c
and then decrease almost linearly with increasing temperature, changing sign from positive to negative nearT 150 K. The features of the resistivity and TEP temperature dependences (the lawT
2 changing toT, the change in the sign of S with temperature, and the low TEP anisotropy at large anisotropy) have been interpreted in the framework of the narrow-band model. 相似文献
70.
A. A. Belousov Yu. I. Berdyshev A. G. Chentsov A. A. Chikrii 《Cybernetics and Systems Analysis》2010,46(5):718-723
A game problem of the successive capture of a team of evaders by a single pursuer under conditions of “simple motions” of
the players is analyzed. The performance criterion is the total time all the evaders are captured. It is assumed that the
pursuer is guided by the parallel pursuit law. In such a case, the optimal response of the evaders is the straightforward
motion with maximum speed. The original infinite-dimensional problem can therefore be reduced to two finite-dimensional problems. 相似文献