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991.
992.
Eslami Vahideh Ashofteh Parisa-Sadat Golfam Parvin Loáiciga Hugo A. 《Water Resources Management》2021,35(12):4085-4110
Water Resources Management - Environmental Impact Assessments (EIAs) of development projects are necessary to minimize negative impacts and maximize benefits. The objective of this paper is to... 相似文献
993.
The dependence of the magnetic momentm obtained from the hysteresis loops on the speed of the magnetic field sweep
=dH
ext/dt is explained on the basis of Anderson's interpretation of the magnetic flux creep. In addition, a phenomenological model is suggested which predicts a linear dependence ofm on ln
with the slope m/ ln
, numerically equal to the relaxation rate m/ ln(t) from the usual magnetic relaxation. Such linear relations betweenm and ln
were observed experimentally in single crystals of YBaCuO. Preliminary experiments on the complementary time dependent relaxation ofm after a simulated step change ofH
ext gave mostly relaxation rates close to the predicted values. The model here presented also enables one to compare the critical state in the superconductor at a field sweep rate
with the critical state at some timet
eff after a step change ofH
ext. The values of
analyzed in our experiments actually correspond to the critical state at timest
eff between0.04 and4 sec after an imaginary large step change ofH
ext. 相似文献
994.
995.
The - transformation of Si3N4 during liquid-phase sintering appears to be controlled by the growth of the -Si3N4 grains in the direction perpendicular to thec-axis in the case of MgO additive. The diffusion through the liquid is the rate-controlling step in the case of the Y4Al5O12 additive. The density of the sintered body at the solid skeleton stage was influenced by the change in the - transformation rate and/or by a change of the transformation mechanism. The indirect proportionality between the -phase content in the starting powder and the density at the solid skeleton stage was found. The microstructure of the sintered body is influenced by both the -phase content in the starting powder and the chemical composition of the additive. Fine, uniform microstructure with a high aspect ratio of -grains is obtained, when the -phase content in the starting powder is as small as possible and when the - transformation is controlled by grain growth. 相似文献
996.
Anna Sztaniszlav Magdolna Balla Maria Farkas-Jahnke Csaba Novák 《Journal of Materials Science》1990,25(5):2353-2358
The kinetics of solid-state reactions of powdered reactants were investigated by X-ray and by differential thermogravimetry in a magnetic field. Measurements revealed mutual diffusion of the Fe3+ and In3+ ions in the Fe2O3-In2O3 system heat treated for 3 h at 700 to 1400° C. Diffusion of indium into the Fe2O3 lattice caused a shift of the Curie temperature of the antiferromagnetic iron oxide towards lower temperatures. Only Caln2O4 was found between CaCO3 and In2O3 up to 1400° C. Also, in the Fe2O3-CaCO3-In2O3in system, the reaction started with the mutual diffusion of iron and indium and the forming of CaFe2O4. End-products were the magnetic -Ca4Fe14O25 and CaFe4O7, and the non-magnetic CaFe5O7, depending on the In3+ concentration. Indium stabilized the magnetic calcium-iron oxide structures, shifting their Curie temperatures towards lower values. 相似文献
997.
The microstructural and mechanical properties of mullite-zirconia composites with TiO2 (0.25 and 1.0 mol) additions have been studied, after ageing the samples over a wide temperature range (1000 to 1500° C) for long periods of time (100 to 200 h). In the sample with 0.25 mol TiO2 addition, changes in mullite composition and in the solid state compatibility at temperatures below 1450° C were detected. In the sample containing 1 mol TiO2, decomposition of Al2TiO5 occurs atT1200° C. Both compositions exhibit no increment in zirconia average grain size during ageing and, concomitantly, there is no strength degradation until higher temperatures (>1400° C) are reached, which become more drastic when Al2Ti5 is present. 相似文献
998.
999.
Pena Julio Nápoles Gonzalo Salgueiro Yamisleydi 《Artificial Intelligence Review》2021,54(5):3817-3847
Artificial Intelligence Review - Attribute weighting is a task of paramount relevance in multi-attribute decision-making (MADM). Over the years, different approaches have been developed to face... 相似文献
1000.
Nowadays, cities are the most relevant type of human settlement and their population has been endlessly growing for decades. At the same time, we are witnessing an explosion of digital data that capture many different aspects and details of city life. This allows detecting human mobility patterns in urban areas with more detail than ever before. In this context, based on the fusion of mobility data from different and heterogeneous sources, such as public transport, transport‐network connectivity and Online Social Networks, this study puts forward a novel approach to uncover the actual land use of a city. Unlike previous solutions, our work avoids a time‐invariant approach and it considers the temporal factor based on the assumption that urban areas are not used by citizens all the time in the same manner. We have tested our solution in two different cities showing high accuracy rates. 相似文献