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31.
Cod (mean start weight of 26 g) were fed three diets for 15 months, each based on a dry pellet coated at a level of 9g/100
g with soybean oil, capelin oil or sardine oil. The fatty acid compositions of neutral lipids and four glycerophospholipids
of white muscle, liver, gills and heart were determined. The fatty acid composition of dietary lipids influenced the composition
of neutral lipids in all organs. Linoleic acid (18∶2n−6) from soybean oil was selectively incorporated into phosphatidylcholine
of the four tissues. Similar levels of 20∶5n−3 and 22∶6n−3 in phosphatidylcholine and phosphatidylethanolamine were found
in all organs from cod fed capelin oil and sardine oil in spite of highly differentiated feed fatty acid levels. The polyunsaturated
fatty acid (PUFA) composition of phosphatidylinositol was least influenced by dietary lipids. The preferred monoenic fatty
acid in phospholipids of cod was 18∶1n−9, independent of dietary intake, whereas the longer chain monoenoic acids seemed to
be preferentially catabolized. The results suggest that 20∶4n−6 as well as 20∶5n−3 and 22∶6n−3 fatty acids are essential for
cod. 相似文献
32.
This paper presents a contingency screening method and a framework for its on-line implementation. The proposed method carries out contingency screening and on-line stability assessment with respect to first-swing transient stability. For that purpose, it utilizes the single machine equivalent method and aims at improving the prior developed contingency screening approaches. In order to determine vulnerability of the system with respect to a particular contingency, only one time-domain simulation needs to be performed. An early stop criteria is proposed so that in a majority of the cases the simulation can be terminated after a few hundred milliseconds of simulated system response. The method’s outcome is an assessment of the system’s stability and a classification of each considered contingency. The contingencies are categorized by exploiting parameters of an equivalent one machine infinite bus system. A novel island detection approach, appropriate for an on-line application since it utilizes efficient algorithms from graph theory and enables stability assessment of individual islands, is also introduced. The New England and New York system as well as the large-scale model of the Continental-European interconnected system are used to test the proposed method with respect to assessment accuracy and computation time. 相似文献
33.
Christian Thaulow Stella V. Schieffer Inga R. Vatne Dipanjan Sen Erling Østby 《Computational Materials Science》2011,50(9):2621-2627
We analyze the fracture of single crystal silicon simulated by atomistic modeling with ReaxFF first principles based reactive force field. The simulations are performed at three temperatures: 500 K, 800 K and 1200 K, capturing both brittle and ductile behavior for the selected crystallographic orientation with (1 0 0) as the fracture plane. Three failure mechanisms are observed: bond breaking, amorphization and emission of dislocations. We demonstrate that the Crack Tip Opening Displacement (CTOD) gives a realistic estimate of the fracture toughness of brittle fracture, linking continuum mechanics fracture theory with the direct crack tip atomistic approach. We discuss the physics based mechanisms of failure in silicon in view of the CTOD measurements. 相似文献
34.
Anne Falk Øgaard Trine A. Sogn Susanne Eich-Greatorex 《Nutrient Cycling in Agroecosystems》2006,76(1):39-48
The aim of the present investigation was to study the effect of manure on retention of selenium (Se) in soil. Addition of cattle manure in combination with selenite and selenate reduced the adsorption of both anions to a loam soil in a batch experiment. The results were explained by the content of low-molecular-weight organic acids in the manure which compete with Se for the sorption sites. In a pot experiment with loam and peat soils and with two pH levels within each soil, cattle slurry added together with selenate was found to increase the Se concentration in grain at the highest pH level (6.1 and 6.8 for the loam and peat, respectively). At a lower pH (5.4 and 6.0 for the loam and peat, respectively) there was no significant effect of slurry on Se concentration in grain. Application of slurry also increased the residual effect of Se applied to the loam soil in the preceding growing season. In the peat soil, no residual effect of Se was found either with or without the addition of slurry. 相似文献
35.
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37.
Hans Erik Vatne PhD Roar Ørsund PhD Knut Marthinsen PhD Erik Nes 《Metallurgical and Materials Transactions A》1996,27(12):4133-4144
A physically based model for the evolution of recrystallization microstructures and textures during hot rolling of aluminum
is presented. The approach taken differs from similar models developed for steels. The present model is based on recent experimental
investigations directed toward identifying the nature of the nucleation sites for recrystallized grains of different crystallographic
orientations. Particle stimulated nucleation (PSN) and nucleation from cube bands and grain boundary regions have been incorporated
in the model. The multipass aspect complicates the modeling due to partial recrystallization between the rolling passes. Two
different approaches have been suggested to handle this. The model has been applied to predictions of recrystallization kinetics,
recrystallized grain sizes, and recrystallization textures during multipass hot rolling of aluminum. The predictions are reasonable
compared to experimental results. 相似文献
38.
Madsen Per Jensen Ole Kiel Amtoft Torben Reynisson Ragnar V. Mikkelsen Jan Hvolgaard Laursen SØren Kolding Troels Emil Larsen Torben Jenner Michael Bohl 《Wireless Personal Communications》2002,23(1):55-66
Unified RF requirements are derived for an UMTS Terrestrial RadioAccess/Frequency Division Duplex (UTRA/FDD) compliant mobile transceiver. Aset of transceiver requirements are proposed with consideration to systemissues including duplex aspects. From these design-compatible requirements areproposed for each functional block in the transceiver. 相似文献
39.
The hypernetted-chain (HNC) method for quantum many-body calculations is investigated in some detail by means of calculations of the binding energy and the equilibrium density for liquid4He. The calculations are done for six different two-body potentials, and the results are compared with experimental results and other theoretical results obtained by the lowest order constrained variation (LOCV) method. Our HNC results are, in general, quite different from the results obtained by the LOCV method—the LOCV binding energies are generally reduced by 2–5 K in the HNC calculations. The results are also very dependent on the chosen potential, especially at high densities. 相似文献
40.
Jilai Xue Harald A. Øye Dr. techn. 《JOM Journal of the Minerals, Metals and Materials Society》1992,44(11):28-34
The wettable cathode is one of the most promising medium-term modifications to the Hall-Héroult process. For implementing this concept, cathode materials of anthracite or semigraphitized carbon matrices with TiB2 (up to 50 wt. %) have been made and evaluated in the laboratory. In this article, the sodium penetration, abrasion resistance, electrical resistivity, and crushing strength are discussed in relation to the cathode performance in aluminum electrolysis. 相似文献