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41.
Single crystals of nearly stoichiometric Fe3Si were creep-deformed at temperatureT = 450 to 850° C and applied stress=40 to 250 MPa. While the temperature dependence of the steady-state creep rate of crystals with less than 25 at% Si can be described by an exponential function exp (–H
exp/kT), the Fe-26 at% Si samples show an exponential dependence only below 500° C and above 600° C. At intermediate temperatures the dependence is weak. It is suggested that in this intermediate range two phases exist. The experimental results are consistent with the assumption that the phase boundaries do not hinder dislocation movement, and that the disocation velocity in the two phases is different. 相似文献
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Pavel Krömer Jan Platoš Václav Snášel 《International journal of parallel programming》2014,42(5):681-709
Graphic processing units (GPUs) emerged recently as an exciting new hardware environment for a truly parallel implementation and execution of Nature and Bio-inspired Algorithms with excellent price-to-power ratio. In contrast to common multicore CPUs that contain up to tens of independent cores, the GPUs represent a massively parallel single-instruction multiple-data devices that can nowadays reach peak performance of hundreds and thousands of giga floating-point operations per second. Nature and Bio-inspired Algorithms implement parallel optimization strategies in which a single candidate solution, a group of candidate solutions (population), or multiple populations seek for optimal solution or set of solutions of given problem. Genetic algorithms (GA) constitute a family of traditional and very well-known nature-inspired populational meta-heuristic algorithms that have proved its usefulness on a plethora of tasks through the years. Differential evolution (DE) is another efficient populational meta-heuristic algorithm for real-parameter optimization. Particle swarm optimization (PSO) can be seen as nature-inspired multiagent method in which the interaction of simple independent agents yields intelligent collective behavior. Simulated annealing (SA) is global optimization algorithm which combines statistical mechanics and combinatorial optimization with inspiration in metallurgy. This survey provides a brief overview of the latest state-of-the-art research on the design, implementation, and applications of parallel GA, DE, PSO, and SA-based methods on the GPUs. 相似文献
44.
T. Kanerva V. Kröger K. Rahkamaa-Tolonen M. Vippola T. Lepistö R. L. Keiski 《Topics in Catalysis》2007,45(1-4):137-142
Laboratory-scale ageing and poisoning procedures were performed on selected diesel catalysts. The results showed that phosphorus
poisoning together with high temperature ageing has a strong effect on the catalytic activity and microstructure of platinum
containing catalysts. Phosphorus poisoning contaminated the catalysts resulting in phosphate formation, e.g. CePO4 and AlPO4. Poisoning and air ageing increased platinum particle-size and washcoat grain-size. 相似文献
45.
Ekkehard H. Lutz 《Journal of the American Ceramic Society》1994,77(5):1274-1280
Plasma spraying, originally a surfacing technology used for ceramic coating of metal and nonmetal substrates, is suitable for producing large, full ceramic bodies, such as plates and tubes, in situ to almost the desired dimensions; i.e., conventional methods of designing by molding and casting green bodies followed by sintering are not required. These "plasma ceramics" exhibit characteristic mechanical and thermomechanical properties. Their porous laminar grain structure results in low E -modulus and strength, and in extreme thermal shock resistance, which is enhanced by the comparably high fracture resistance of the material. Because of these properties and their low hardness, plasma ceramics can be easily machined with almost conventional methods of metal processing. 相似文献
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Wey Yang Teoh Frans Denny Rose Amal Donia Friedmann Lutz Mädler Sotiris E. Pratsinis 《Topics in Catalysis》2007,44(4):489-497
A comparative photocatalytic analysis was carried out on TiO2 made in a Flame Spray Pyrolysis (FSP) process and flame-made Degussa P25. Both have similar crystallinity, phase composition,
phase segregation and a non-porous surface. Hence comparison was made based on their difference in specific surface area,
organic adsorption and the amount of OH• generated upon illumination. The photocatalytic activity tests were carried out using
the following series of organic compounds: sucrose, glucose, fructose, maleic acid, glyoxylic acid, oxalic acid, isobutyric
acid, phenol and methanol. FSP-made TiO2 outperformed P25 for saccharides mineralisation, while for phenol and methanol mineralisation P25 was better than FSP-made
TiO2. Similar mineralisation rates were observed for both FSP-made and P25 TiO2 for the mineralisation of carboxylic acids. This shows that the relative performance of the photocatalysts depends on the
type of organic compounds to be degraded. The high surface area and possibly a more efficient interfacial charge transfer
of FSP-made TiO2 provided an efficient pathway for saccharides mineralisation. As for phenol and methanol, the mineralisation rates were higher
when using P25 due to the greater amount of OH• radicals generated by this photocatalyst. The fast mineralisation rates of
carboxylic acids made degradation of these organic compounds to be less affected by the TiO2 photocatalyst properties and conditions tested in this work. 相似文献
50.
Sintered negative electrodes for nickel-cadmium secondary cells were studied. Model electrodes prepared by means of three different impregnation methods were evaluated. It was demonstrated that the impregnation procedure may affect properties of active mass and the service life of electrodes in a significant way. 相似文献