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71.
Yu. I. Golovin 《Journal of Materials Science》2004,39(16-17):5129-5134
An influence of steady, pulse and microwave magnetic fields on mechanochemical reactions between structural defects in doped ionic crystals has been studied. The effects of dislocation depinning, dislocation mobility increase, macroplastic unhardening and magnetoresonant softening in magnetic fields have been revealed. It is shown that the magnetosensitive spin-dependent reactions between structural defects is the reason of magnetoplastic effects in nonmagnetic crystals. It means that the electron and nuclear spin states of the paramagnetic defects play an important role in the formation of mechanical properties of crystals in magnetic fields and without them. 相似文献
72.
A. D. Bulanov A. N. Moiseev O. Yu. Troshin V. V. Balabanov D. V. Isaev 《Inorganic Materials》2004,40(6):555-557
High-purity isotopically enriched (99.98% 28Si, 99.57% 29Si, and 99.83% 30Si) silane samples are prepared for the first time. The total hydrocarbon content of the samples is no higher than 0.1–0.3 ppm. The concentration of electroactive impurities in the silicon prepared from the purified monoisotopic silane is below 1015 cm–3. 相似文献
73.
I. A. Grishin V. A. Gur'ev E. B. Intyushin Yu. E. Elliev A. P. Savikin 《Inorganic Materials》2004,40(4):431-433
TeO2–WO3 glasses coactivated with Er3+ and Yb3+ are prepared. The effect of Yb content on the efficiency of Er photoluminescence (PL) in the visible and IR spectral regions is studied. The highest PL efficiency is achieved at an Er : Yb atomic ratio of 1 : 1. The PL lifetime for the Er3+
4
I
13/2 level is determined to be 7–9 ms. 相似文献
74.
V. N. Perevezentsev M. Yu. Shcherban’ M. Yu. Murashkin R. Z. Valiev 《Technical Physics Letters》2007,33(8):648-650
The structure and mechanical properties of nanocrystalline aluminum alloy 1570 obtained by means of severe plastic deformation have been studied. Being tested in a temperature range from 300 to 400°C, the alloy exhibits high-strain-rate superplasticity. At 400°C, the superplasticity is manifested in a very broad range of strain rates, extending from 5 × 10?3 to 1 s?1. 相似文献
75.
Broadband chaotic oscillations were monitored in a depressed potential collector of a traveling-wave oscillator (TWO). This signal appears due to the oscillations of a virtual cathode, which is formed in the spent electron beam under the action of retarding fields existing in the multistage depressed collector. 相似文献
76.
V. V. Mamutin O. V. Bondarenko A. P. Vasil’ev A. G. Gladyshev A. Yu. Egorov N. V. Kryzhanovskaya V. S. Mikhrin V. M. Ustinov 《Technical Physics Letters》2007,33(5):384-387
The optical properties of heterostructures comprising InAs/InGaAsN quantum wells in strain-compensated GaAsN/InGaAsN superlattices have been studied. It is demonstrated that, using such superlattices of various design and thickness and with additional InAs monolayer spacers, it is possible to control the wavelength of room-temperature emission from InGaAsN quantum wells within 1.3–1.6 μm without deteriorating the output radiation characteristics, which opens additional prospects for the development of lasers on GaAs substrates for telecommunication applications. 相似文献
77.
V. Yu. Karpov 《Materials Science》2007,43(5):746-749
We developed a new type of porous materials with anisotropic structure based on a large number of metals. It is shown that
these material, called gasars, have properties different from the properties of the other porous materials. Thus, the strength
of gasars is much higher than the strength of powder materials with the same porosity and their impact toughness is readily
regulated by the sizes of the pores. The internal structures of gasars and possible versions of the types of pores in these
materials are strongly diversified, which makes the spectrum of their possible applications very wide. We discuss some specific
directions of the potential applications of gasars. The results of measurements of the thermal conductivity of gasars and
monolithic specimens are presented. It is shown that, for a certain level of porosity, the specific thermal conductivity of
gasars is higher than for monolithic materials. We also make some basic conclusions concerning the characteristics of new
porous materials.
__________
Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 5, pp. 125–127, September–October, 2007. 相似文献
78.
79.
Filled fibrous sorbents modified with transition metal ferro- and ferricyanides capable to recover americium(III) and rare-earth metals(III) from nitric acid solutions were prepared. The most complete and rapid recovery is attained on complex-forming and cation-exchange sorbents (as filled fibrous materials) saturated with nickel ions. The sorbents are characterized by good kinetic properties and can be used for recovery of the above metals. 相似文献
80.
Production methods used to prepare graphite crucibles with high operating properties are considered: use as a filler of good
graphitizing acicular coke, vibration molding of the original coke mix, use of production cycles for impregnation with medium
temperature coal-tar pitch — firing, firing of compacted billets in metal containers, graphitization of fired billets in graphite
cylinders. The last two production methods make it possible to reduce the temperature drop throughout the volume of a billet
during heat treatment, and as a consequence to reduce crack development to a minimum as a result of reducing thermal stresses.
All of the production methods recommended may be entirely accomplished in existing electrode plants and may be used to increase
markedly the quality crucible graphite. It is possible to achieve a quality for these materials at the best world level.
Translated from Novye Ogneupory, No. 8, pp. 28–33, August 2008. 相似文献