排序方式: 共有27条查询结果,搜索用时 234 毫秒
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Ji?í Jeništa Hidemasa Takana Hideya Nishiyama Milada Bartlová Vladimír Aubrecht Petr K?enek Viktor Sember Alan Mašláni 《Computer Physics Communications》2011,182(9):1776-1783
The paper presents numerical simulations of the discharge and the near-outlet regions of the hybrid-stabilized argon–water electric arc. Two different numerical methods for solving the set of conservative equations for the continuity, momentum and energy have been applied. The major difference between the results using the two methods occurs in the temperature distribution in arc fringes within the discharge chamber. This fact influences the potential drop, overpressure, reabsorption of radiation and arc efficiency. It is shown that the radial profiles of temperature at the exit nozzle are less influenced by different temperature distribution within the discharge chamber. Comparison with chosen experimental temperature profiles shows very good agreement. 相似文献
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Zdeňka Řiháková Milada Plocková Vladimír Filip Jan Šmidrkal 《European Food Research and Technology》2001,213(6):488-490
The antifungal effects of lauric acid and four lauric acid derivatives (monolauroylglycerol, D-laurate A, T-laurate A, 6-O-lauroysucrose) were tested on the spore germination and the growth rate of Aspergillus niger DMF 0801. The results showed that the tested substances varied in their antifungal activity and they also confirmed the relation of the structure of tested substances and their antifungal effects. Monolauroylglycerol at concentration level between 0.2 and 1.8 mmol l-1 caused the highest inhibition of spore outgrowths whereas 6-O-lauroysucrose at concentration between 0.05 and 1.8 mmol l-1 did not exhibit inhibition of spore germination. The inhibition of colony growth rate was detected mainly at presence of 6-O-lauroysucrose. 相似文献
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Lipidomic Study of Precursors of Endocannabinoids in Freshwater Bryozoan Pectinatella magnifica
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Freshwater bryozoan Pectinatella magnifica was collected from a sand pit (South Bohemia). The total lipids after extraction from lyophilized bryozoans were analyzed using high‐performance liquid chromatography/high‐resolution negative tandem electrospray mass spectrometry. A total of 19 lipid classes were identified, including N‐acyl‐substituted phospholipids, that is, N‐acylphosphatidylethanolamine and N‐acylphosphatidylserine in their plasmenyl forms. Based on gas chromatography/mass spectrometry of 3‐pyridylcarbonyl (picolinyl) esters, a very unusual fatty acid was identified, namely 24:7n‐3 (all‐cis‐3,6,9,12,15,18,21‐tetracosaheptaenoic acid). The presence of polyunsaturated fatty acids in individual classes is very specific: arachidonic and eicosapentaenoic acids being predominantly bound as amides in N‐acyl phospholipids, that is, diacyl‐N‐acylphosphatidylethanolamines (NAPtdEtn), plasmenyl‐N‐acylphosphatidyl ethanolamines (PlsNAPtdEtn), diacyl‐N‐acylphosphatidylserines (NAPtdSer), and plasmenyl‐N‐acylphosphatidylserines (PlsNAPtdSer). While 24:6n‐3 was identified in the sn‐2 position of several phospholipids, 24:7n‐3 was identified in only two plasmalogens, that is, PlsNAPtdEtn and PlsNAPtdSer. Thanks to the tandem mass spectrometry, we managed to identify the position of all acyl groups in both diacyl‐ and also in alkenyl‐acyl‐(plasmenyl) molecular species of N‐acylphospholipids. The identification of the molecular species of N‐acyl‐substituted phosphatidylethanolamine and phosphatidylserine, including their plasmalogen forms, in the freshwater bryozoan P. magnifica has enabled the identification of endogenous cannabinoid precursors. 相似文献
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Petr? Milada; ?pinka Marek; Lhota Stanislav; ?ípek Petr 《Canadian Metallurgical Quarterly》2008,122(1):9
Although head rotations are frequent patterns in play behavior in many mammalian species and differ from head movements used in other contexts, they have not been quantitatively described and their function remains unclear. The head rotations occurring in the play behavior of free-ranging Hanuman langurs (Semnopithecus entellus) were described from videotaped sequences. The authors tested 2 possible hypotheses about their function. Either the head rotations serve to create unexpected situations and should therefore occur in both solitary and social play and also be very variable, or they serve as play signals and should therefore occur only in social play and be ritualized. If head rotations have both functions, they should be less variable in social play. The data revealed that head rotations were very variable and were present both in solitary and social play. Furthermore, there was no difference in the variability between the head rotations present in the 2 types of play. The results do not support the function of head rotations as play signals but, rather, suggest that head rotations may serve to create unexpected situations in play. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Miller Ann M.; Miller Robert B.; Obermeyer William H.; Behan Mary; Benca Ruth M. 《Canadian Metallurgical Quarterly》1999,113(4):755
A variety of sensory stimuli (e.g., visual, auditory, and thermal) are known to induce rapid eye movement (REM) sleep in mammals. Studies have examined the induction of REM sleep in albino rats by light-to-dark transitions, a phenomenon referred to as REM sleep triggering. Recent research has demonstrated that aspiration lesions of the superior colliculus (SC) and pretectal area attenuated REM sleep triggering. To define more specifically the area or areas involved in mediating REM sleep responses to changes in illumination, fiber-sparing neurotoxic lesions were made to the pretectum (PT) or the SC. Lesions of the PT attenuated REM sleep triggering, whereas lesions of the SC did not. Thus, the role of the PT may be expanded to include the regulation of REM sleep in response to photic stimulation in albino rats. These findings provide a paradigm in which to study mechanisms of REM sleep generation and the effects of light on behavioral state. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Impedance measurement of growth of lactic acid bacteria in the presence of nisin and lysozyme 总被引:1,自引:0,他引:1
Drahomíra?KozákováEmail author Jitka?Holubová Milada?Plocková Jana?Chumchalová Ladislav??urda 《European Food Research and Technology》2005,221(6):774-778
Effect of nisin (0.500 g/l), lysozyme (0.035 g/l) and the mix of nisin (0.500 g/l) and lysozyme (0.035 g/l) against two nisin-producing
lactococci strains, three non-nisin-producing lactococci strains and four lactobacilli strains with antimicrobial activity
was determined by the impedimetric method. None of the tested lactococci and lactobacilli strains were inhibited by lysozyme
at concentration of 0.035 g/l. Only the nisin-producing lactococci strains were resistant to nisin at 0.500 g/l, the other
lactococci and lactobacilli were inhibited by nisin at 0.500 g/l intensively. The mix of lysozyme and nisin displayed a comparable
effect to the nisin addition against the used lactococci strains and was very variable depending on the strain of tested lactobacilli.
The impedimetric method was shown to be convenient for screening the growth abilities of lactococci and lactobacilli in the
presence of antimicrobial components. 相似文献
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The uptake of emulsified labeled lipids by rat heart mitochondria was studied. Divalent cations greatly stimulated uptake
of cholesterol in emulsions containing phospholipids; the effect increased with increasing atomic number. Epinephrine and
norepinephrine were also stimulatory. Lipid-depleted mitochondria were less effective in taking up cholesterol unless lecithin
or serum lipids were included in the emulsion. Addition of iodoacetamide did not inhibit uptake, while use of heated mitochondria
or extremes of pH augmented lipid uptake. Thus the process appears to be non-enzymatic. While lecithin emulsions showed no
visible change on addition of calcium ions, phosphatidylethanolamine emulsions became turbid and the turbidity was largely
removed by addition of heparin. Heparin as well as chondroitin sulfate B and nonionic detergent did inhibit lipid uptake by
mitochondria. The possible role of such nonenzymatic lipid uptake in membrane formation and cholesterol accumulation is discussed. 相似文献
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Lato Pezo Milada Pezo Aca Jovanović Radmilo Čolović Đuro Vukmirović Vojislav Banjac Olivera Đuragić 《Advanced Powder Technology》2018,29(7):1734-1741
In this study, the mixing performance of coupled mixing action of the Komax static mixer (which is used as a pre-mixer) and rotating drum (applied as the final mixer) was explored in the maize meal mixing operation. The main objective of this paper was to predict the behaviour of the previously grinded maize particles, during the mixing process in static mixer and drum mixer, and to explore the possibilities to shorten the mixing time in the main mixer (in order to reduce the energy consumption).Three different experiments were performed: in the first experiment, possibilities of static mixer were explored, second experiment showed the mixing performance of rotating drum, and the combination of these two mixing devices was investigated in the third experiment. Homogeneity of the obtained mixtures was determined experimentally, by the “Microtracers” method.The Discrete Element Method was used for modelling of granular flow in the pre-mixing and final mixing applications, and to predict the inter-particle mixing quality within a static mixer and the rotating drum mixer. The results of the numerical simulation are compared with appropriate experimental results. The possible industrial application of this model could be the optimization of parameters of mixing systems taking into account the quality and the duration of the mixing process. 相似文献