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971.
The data on phase transitions in bis(trifluoroethoxy)phosphazene were examined and generalized. Their nature was determined and the mechanism of the transitions was described. Schemes were proposed for the phase transitions that take into account the conditions of fabrication and thermal history of the samples. Translated from Khimicheskie Volokna, No. 5, pp. 24–27, September–October, 1998. 相似文献
972.
A comparative analysis of the efficiency of removing surfactants from wastewaters by different fibre chemisorbents was conducted. In studying the chemical stability of the chemisorption materials with respect to aggressive media, their good resistance to weakly basic and acid media was determined. Translated from Khimicheskie Volokna, No. 4, pp. 48–50, July–August, 1998. 相似文献
973.
974.
S. Gamburzev W. Zhang O. A. Velev S. Srinivasan A. J. Appleby A. Visintin 《Journal of Applied Electrochemistry》1998,28(5):545-549
A laboratory metal hydride/air cell was evaluated. Charging was via a bifunctional air gas-diffusion electrode. Mixed nickel and cobalt oxides, supported on carbon black and activated carbon, were used as catalysts in this electrode. At 30mAcm–2 in 6m KOH, the air electrode potentials were –0.2V (oxygen reduction) and +0.65V (oxygen evolution) vs Hg/HgO. The laboratory cell was cycled for 50 cycles at the C/2 rate (10mAcm–2). The average discharge/charge voltages of the cell were 0.65 and 1.6V, respectively. The initial capacity of the metal hydride electrode decreased by about 15% after 50 cycles. 相似文献
975.
Polythiophene films were electrochemically deposited on glassy carbon substrates under potentiostatic control and used as cathode active material together with a Zn anode in a rechargeable battery with propylene carbonate, Zn(ClO4)2, LiClO4 electrolyte. Charge–discharge characteristics were studied. The average discharge voltage of the polythiophene/Zn cell was 1.25V. In the low current density region (i.e. 10–50μAcm?2) the cycling coulombic efficiency was above 95%, but in the fast charge–discharge region, where current densities were 0.1–0.5mAcm?2, the coulombic efficiency decreased to 55% with increasing discharge rate. Additionally, it was found that the cyclic coulombic efficiency was a function of the charging depth. 相似文献
976.
An empirical approach has been developed to predict the total entrainment flux at different levels of freeboard height. The approach is based on the results of experimental investigations carried out in a 152 mm diameter column, with FCC as the feed powder. The powder was fluidized at superficial gas velocities of 0.2 m/s and 0.7 m/s. 相似文献
977.
This paper presents a general methodology to determine reaction mechanisms using in situ measurement of concentration and reaction rate of intermediates. The criteria for testing the validity of a reaction sequence are discussed. An example is given for a heterogeneous catalytic reaction, the decomposition of ozone on manganese oxide. This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
978.
V. N. Strekalovskii é. G. Vovkotrub A. I. Lipchak S. G. Mikhailov V. I. Solomonov 《Refractories and Industrial Ceramics》1999,40(1-2):51-55
The method of pulse high-current cathode luminescence is used to study the Bi2O3-Er2O3-CeO2 system at room temperature in air. New luminescence centers associated presumably with cation vacancies and an anion vacancy are determined in systems containing CeO2. The luminescence parameters are shown to behave nonmonotonically with variation of the composition of the system. It is assumed that an abrupt change in these parameters at a certain composition of the substance corresponds to a phase transformation. 相似文献
979.
980.
Synthesis of stable boehmite sols and structural properties of the sol–gel-derived γ-alumina using alkoxides, commercial boehmite powders, and aluminum chloride were studied for cost-effective preparation of high quality γ-alumina granules. Stable boehmite sols could be prepared from aluminum butoxide, aluminum isopropoxide, and commercial boehmite powders but not from aluminum chloride. The stable sol-derived γ-alumina has large surface area and nanopore size with uniform pore size distributions. Mesoporous spherical γ-alumina granules were prepared by an oil-drop process from aluminum butoxide, aluminum isopropoxide and a commercial boehmite powder under specific conditions. The sol–gel-derived γ-alumina granules are better than the commercial γ-alumina granules in terms of the pore structure and mechanical strength. The successful synthesis of γ-alumina granules by the sol–gel method from the commercial boehmite powder provides a basis for large-scale, cost-effective production of the high quality γ-alumina granules for use as sorbents or catalysts in industrial processes. 相似文献