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951.
Hydrogenation of canola oil in the presence of nickel and the methyl benzoate-chrome carbonyl complex 总被引:1,自引:0,他引:1
L. J. Rubin S. S. Köseoglu L. L. Diosady W. F. Graydon 《Journal of the American Oil Chemists' Society》1986,63(12):1551-1557
Canola oil was hydrogenated using a mixture of homogeneous methyl benzoate-Cr(CO)3 and heterogeneous nickel catalysts. The effect of the methyl benzoate-Cr(CO)3_to-nickel ratio on the activity, specific isomerization index, linoleate and linolenate selectivities, and fatty acid composition
was evaluated, and the results compared with those obtained with commercial nickel catalyst and methyl benzoate-Cr(CO)3 used individually. At higher chromium-to-nickel ratios the activity of nickel was inhibited and the system behaved essentially
like the pure chrome complex, while at low chromium-to-nickel ratios the characteristics of the nickel predominated. In a
short transition zone relatively high reaction rates were obtained with significantly reducedtrans-isomer levels in the product. In a broader sense, it may be possible to combine a homogeneous and heterogeneous catalyst
while retaining the advantages of both. We may thus be able to design catalyst systems for specific applications. 相似文献
952.
Entrained double oxide films have been held responsible for reductions in mechanical properties in aluminum casting alloys.
However, their behavior in the liquid metal, once formed, has not been studied directly. It has been proposed that the atmosphere
entrapped in the double oxide film defect will continue to react with the liquid metal surrounding it, perhaps leading to
its elimination as a significant defect. A silicon-nitride rod with a hole in one end was plunged into liquid aluminum to
hold a known volume of air in contact with the liquid metal at a constant temperature. The change in the air volume with time
was recorded by real-time X-ray radiography to determine the reaction rates of the trapped atmosphere with the liquid aluminum,
creating a model for the behavior of an entrained double oxide film defect. The results from this experiment showed that first
oxygen, and then nitrogen, was consumed by the aluminum alloy, to form aluminum oxide and aluminum nitride, respectively.
The effect of adding different elements to the liquid aluminum and the effect of different hydrogen contents were also studied.
This article is based on a presentation made in the John Campbell Symposium on Shape Casting, held during the TMS Annual Meeting,
February 13–17, 2005, in San Francisco, CA. 相似文献
953.
Tests of the applicability of new insulation systems for traction motors are considered. Selections of operating loads applied during accelerated comparative testing and the testing technique are described. 相似文献
954.
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957.
V. V. Teleshov 《Russian Metallurgy (Metally)》2007,(2):161-165
Experimental data are often approximated by two-parameter relations in the form of a power or an exponential function. When a number of similar objects are considered, the parameters of these relations are connected by a correlation dependence. The examples of empirical relations where this dependence is observed are considered. In all cases of this correlation dependence, the value of an approximating function changes by several orders of magnitude when its argument varies by several times, and the initial data for the calculation of the empirical-equation parameters are located in a relatively narrow band in the coordinate space. This behavior is always accompanied by a linear relationship between the empirical coefficients of the equations obtained for a number of similar objects. 相似文献
958.
Dandeneau Stéphane D.; Baldwin Mark W.; Baccus Jodene R.; Sakellaropoulo Maya; Pruessner Jens C. 《Canadian Metallurgical Quarterly》2007,93(4):651
Personality processes relating to social perception have been shown to play a significant role in the experience of stress. In 5 studies, the authors demonstrate that early stage attentional processes influence the perception of social threat and modify the human stress response. The authors first show that cortisol release in response to a stressful situation correlates with selective attention toward social threat. Second, the authors show in 2 laboratory studies that this attentional pattern, most evident among individuals with low self-esteem, can be modified with a repetitive training task. Next, in a field study, students trained to modify their attentional pattern to reduce vigilance for social threat showed lower self-reported stress related to their final exam. In a final field study with telemarketers, the attentional training task led to increased self-esteem, decreased cortisol and perceived stress responses, higher confidence, and greater work performance. Taken together, these results demonstrate the impact of antecedent-focused strategies on the late-stage consequences of social stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
959.
M. A. Abroyan S. L. Kosogorov I. V. Nabokova N. A. Uspenskii V. A. Chumichev V. B. Shapiro V. Ya. Shvedyuk 《Instruments and Experimental Techniques》2007,50(4):530-533
A system for real-time measurements of the current-density distribution in electron beams ejected from large-area electron accelerators has been developed. The system, which is based on Faraday cups, a microprocessor, and a PC, is designed for measuring the parameters of the electron beams ejected from large-area accelerators—devices for ionizing electroionization lasers and technological accelerators—and ensures real-time monitoring of the current-density distribution over the electron-beam cross section with a relative measurement accuracy of at least ±2%. 相似文献
960.
S. A. Abramov A. A. Bogolyubskaya V. A. Rostovtsev V. F. Edneral 《Programming and Computer Software》2007,33(2):55-59
An annual report on meetings of the scientific research seminar on computer algebra is presented. 相似文献