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141.
M. Lamirand J. -L. Bonnentien S. Guérin G. Ferrière J. -P. Chevalier 《Metallurgical and Materials Transactions A》2006,37(8):2369-2378
The effect of added oxygen in the range of 1000 to 4000 wt ppm on the microstructures of a Ti-48Al-2Cr-2Nb alloy has been
investigated and compared to the microstructures for a high-purity alloy. For specimens cooled from theα phase, interstitial oxygen stabilizes the lamellar microstructure with respect toγ grains, with higher than equilibrium values for theα
2 volume fraction. For specimens cooled from theα +γ phase field, the lamellar microstructure still tends to be favored by oxygen, but it is found that the phase volume fractions
are not significantly different from equilibrium values. This suggests that interstitial O essentially reduces the kinetics
of theα toα +γ transformation. Thus, interstitial oxygen will have a strong effect on microstructures obtained by continuous cooling fromα, but significantly less on those, such as the duplex microstructure, obtained by long treatment in theα +γ phase field. In general, increased O content is well correlated with reduced ductility. Finally, the role of interstitial
oxygen on this phase transformation is discussed. 相似文献
142.
E. WITTIG DE PENNA P. CARREñO X. URRUTIA L. LOPEZ D. BALLESTER 《Journal of food science》1987,52(5):1434-1435
Cookies enriched with 0, 5, 10, 15, 20, and 25% full-fat sweet lupine flour (FFSL) were evaluated by a sensory panel using the rank of preference and paired comparison tests. Cookies with 0, 5, and 10% FFSL were preferred while those containing 20 and 25% FFSL were rejected (p≤0.01). Studies conducted with school children showed similar acceptability for 0 and 10% FFSL-containing cookies which was different (p = 0.05) from those containing 20% FFSL. Fortification of the basic formula with 10% FFSL was recommended on the basis of acceptability. 相似文献
143.
G. L. Brownell C. A. Burnham C. W. Stearns D. A. Chesler A.-L. Brownell M. R. Palmer 《International journal of imaging systems and technology》1989,1(2):207-217
The development of high resolution PET systems is important for the wider application of this techniques. The resolution of PET is limited by a number of physical factors such as positron range, small angle deviation, and sampling frequency. The design of the detector array and its sensitivity remain critical factors; designs incorporating analog coding have proven to be useful. PCR-I, a single plane PET system, has demonstrated the concept and has produced useful images in animal studies. PCR-II will extend the concept to a two dimensional detector array resulting in a system with high resolution and high sensitivity. 相似文献
144.
Double-step generation of ellipses 总被引:4,自引:0,他引:4
The principle of double-step incremental generation of nonparametric curves on a discrete plane is used to develop a double-step algorithm for scan converting ellipses in sixteen separate segments. The algorithm iterates only half as many times as current algorithms, while each iteration demands the same number of operations or slightly fewer operations than M. Pitteway's (1967, 1985) algorithm (previously the fastest one). This marked gain in the speed of scan conversion is due to the fact that the middle pixel in a two-step increment is obtained without computation 相似文献
145.
Results from laboratory experiments and a 500 tonnes per month pilot plant have been used to draw up criteria for designing the crystallization of an organic salt from its aqueous solution. The crystallization kinetics were determined in a continuous forced circulation crystallizer. The experiments in the forced circulation evaporative crystallizer were carried out and evaluated in accordance with the MSMPR (mixed suspension mixed product removal) concept.The residence time was varied between 0.8 and 10 hours, and the density of the suspension between 180 and 870 kg m?3. It was found that, within the residence time and suspension density ranges studied, growth and nucleation rates have the same dependence on the supersaturation. On the other hand, the nucleation rate decreases with increasing suspension density. If the crystallization kinetics and other design criteria, such as vapour velocity, i.e. supersaturation ratio in the vicinity of the evaporative surface, or height of liquid above the heat exchangers, are taken into account, it is possible to obtain a space—time yield which is five times higher than in the pilot plant, so that the plant to be built can be designed to be correspondingly smaller. 相似文献
146.
An algorithm is introduced which labels formants from the peaks of pole-focused spectra. A clustering procedure is first used to produce line segments of possible formants. These can be considered as anchor traces for the later processing. Rule-based labelling is then applied to provide final formant trace estimates. Experimental results show that the proposed algorithm offers improved formant labelling accuracy. 相似文献
147.
P. C. Wang Z. L. Chen X. M. He L. W. Yin S. L. Wen X. Y. Song 《Ferroelectrics Letters Section》1985,4(2):47-51
The microscopic structures of PLZT(7.9/70/30 and x/65/35, x = 7 or 8) ceramics were studied by means of transmission electron microscopy. The presence of micro-regions in PLZTs was first verfied. 相似文献
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