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1.
复杂蒸馏的最小回流比 总被引:1,自引:0,他引:1
本文提出的直接计算方法不仅适用于多股进料的蒸馏塔,而且也适于有多股侧线抽出的情况。 相似文献
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The adhesion between meat pieces in meat products, varied by the addition of different concentrations of a crude myosin solution, was measured by a trained sensory panel and by two instrumental tests: tensile adhesive strength (TAS) and punch and die. A consumer trial was used to find which level of adhesion was preferred. Results from the sensory panel showed that the adhesion could be detected as highly significant (P < 0·001) differences in three tactile measurements and in the two eating qualities, ease of fragmentation and rubberines. TAS measurements gave larger differences between treatments than punch and die, and had very high correlations with ease of fragmentation and crumblines on cutting. The small consumer study revealed no overall preference for any one product. Hence, although differences in adhesion between meat pieces in a meat product are detectable subjectively and can be measured objectively by TAS tests, preference for any particular strength varies between individuals. 相似文献
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Changes in the neutral lipid (NL), phospholipid (PL) and their fatty acid (FA) profiles in lean samples of cooked and cooked, vacuum-packaged, frozen (28 days) Hereford and Bison L. dorsi muscle were analyzed. Samples from Herefords contained more saturated fatty acids (SFA) in the neutral lipid fraction than Bison. Storage decreased the C18:2, C18:3, C20:1 and C20:4 content of the NL. Bison samples contained more total PL and phosphatidylethanolamine (PE) than Hereford. Storage decreased the content of the least polar of the PL which were eluted in the solvent front (fraction 1), phosphatidylinositol (PI), phosphatidylserine (PS), PE and sphingomyelin (SPH). In the combined PL fraction, there were no differences in the FA profile of Bison and Hereford. Storage resulted in a decrease in the content of C18:2, C20:4, unsaturated fatty acid (UFA) and polyunsaturated fatty acid (PUFA) in the combined PL fraction. In the PE fraction, Bison samples contained more C20:4 and PUFA than Hereford. Storage had no effect on the FA profile of PE. The LPC fraction of Bison samples contained more saturated SFA, UFA and PUFA than Hereford, and with storage these FA decreased. Cooked frozen storage also decreased SFA, UFA and PUFA in PC/LPE. 相似文献
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An evaluation of the effectiveness of adaptive histogram equalization for contrast enhancement 总被引:5,自引:0,他引:5
Zimmerman JB Pizer SM Staab EV Perry JR McCartney W Brenton BC 《IEEE transactions on medical imaging》1988,7(4):304-312
Adaptive histogram equalization (AHE) and intensity windowing have been compared using psychophysical observer studies. Experienced radiologists were shown clinical CT (computerized tomographic) images of the chest. Into some of the images, appropriate artificial lesions were introduced; the physicians were then shown the images processed with both AHE and intensity windowing. They were asked to assess the probability that a given image contained the artificial lesion, and their accuracy was measured. The results of these experiments show that for this particular diagnostic task, there was no significant difference in the ability of the two methods to depict luminance contrast; thus, further evaluation of AHE using controlled clinical trials is indicated. 相似文献
7.
Fractional brownian motion: a maximum likelihood estimator and its application to image texture 总被引:8,自引:0,他引:8
Fractals have been shown to be useful in characterizing texture in a variety of contexts. Use of this methodology normally involves measurement of a parameter H, which is directly related to fractal dimension. In this work the basic theory of fractional Brownian motion is extended to the discrete case. It is shown that the power spectral density of such a discrete process is only approximately proportional to |f|a instead of in direct proportion as in the continuous case. An asymptotic Cramer-Rao bound is derived for the variance of an estimate of H. Subsequently, a maximum likelihood estimator (MLE) is developed to estimate H. It is shown that the variance of this estimator nearly achieves the minimum bound. A generation algorithm for discrete fractional motion is presented and used to demonstrate the capabilities of the MLE when the discrete fractional Brownian process is contaminated with additive Gaussian noise. The results show that even at signal-to-noise ratios of 30 dB, significant errors in estimation of H can result when noise is present. The MLE is then applied to X-ray images of the human calcaneus to demonstrate how the line-to-line formulation can be applied to the two-dimensional case. These results indicate that it has strong potential for quantifying texture. 相似文献
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A comparative electron-microscope study was made of the structural changes brought about in bovine longissimus dorsi muscle by 2-Hz and 60-Hz electrical stimulation. Apart from the frequency difference, the two treatments were identical: 500V AC, 600 pulses (2Hz × 300s and 60 Hz × 10 s), and a time of application of about 40 min post mortem. The low-frequency current produced no detectable tissue disruption or irregularity in sarcomere length, whereas the 60-Hz treatment caused widespread supercontraction and the formation of contraction nodes; many sarcomeres in the internodal zones were stretched or fractured. The observations confirm and extend those of our earlier light-microscope study, and support the view that fiber disruption contributes significantly to the tenderizing effect of high-voltage electrical stimulation. 相似文献
9.
Watkins SM Lin TY Davis RM Ching JR DePeters EJ Halpern GM Walzem RL German JB 《Lipids》2001,36(3):247-254
Diet and fatty acid metabolism interact in yet unknown ways to modulate membrane fatty acid composition and certain cellular
functions. For example, dietary precursors or metabolic products of n-3 fatty acid metabolism differ in their ability to modify
specific membrane components. In the present study, the effect of dietary 22∶6n−3 or its metabolic precursor, 18∶3n−3, on
the selective accumulation of 22∶6n−3 by heart was investigated. The mass and fatty acid compositions of individual phospholipids
(PL) in heart and liver were quantified in mice fed either 22∶6n−3 (from crocodile oil) or 18∶3n−3 (from soybean oil) for
13 wk. This study was conducted to determine if the selective accumulation of 22∶6n−3 in heart was due to the incorporation
of 22∶6n−3 into cardiolipin (CL), a PL most prevalent in heart and known to accumulate 22∶6n−3. Although heart was significantly
enriched with 22∶6n−3 relative to liver, the accumulation of 22∶6n−3 by CL in heart could not quantitatively account for this
difference. CL from heart did accumulate 22∶6n−3, but only in mice fed preformed 22∶6n−3. Diets rich in non-22∶6n−3 fatty
acids result in a fatty acid composition of phosphatidylcholine (PC) in heart that is unusually enriched with 22∶6n−3. In
this study, the mass of PC in heart was positively correlated with the enrichment of 22∶6n−3 into PC. The increased mass of
PC was coincident with a decrease in the mass of phosphatidylethanolamine, suggesting that 22∶6n−3 induced PC synthesis by
increasing phosphatidylethanolamine-N-methyltransferase activity in the heart. 相似文献
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