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31.
Joseph D. Masters 《Geometriae Dedicata》2006,119(1):17-33
We show that every closed, virtually fibered hyperbolic 3-manifold contains immersed, quasi-Fuchsian. 相似文献
32.
The main goal of the present paper is to sharpen some results about the error made when the Wild sums, used to represent the solution of the Kac analog of Boltzmann’s equation, are truncated at the n-th stage. More precisely, in Carlen, Carvalho and Gabetta (J. Funct. Anal.
220: 362–387 (2005)), one finds a bound for the above-mentioned error which depends on (an
Λ+ε). On the one hand, it is shown that Λ, the least negative eigenvalue of the linearized collision operator, is the best possible exponent. On the other hand, ε is an extra strictly positive number and a a positive coefficient which depends on ε too. Thus, it is interesting to check whether ε can be removed from the above bound. According to the aforesaid reference, this problem is studied here by means of the probability distribution of the depth of a leaf in a McKean random tree. In fact, an accurate study of the probability generating function of such a depth leads to conclude that the above bound can be replaced with (a′ n
Λ). 相似文献
33.
蕃茄酱流变特性的数学模型 总被引:1,自引:0,他引:1
把化工领域中的Casson模型和Power-lawPlashc模型用于描述蕃茄酱的流变特性,经回归分析验证它们都具有良好的相关程度.用残差平方和分析方法检验,在同样条件下,用Casson模型描述蕃茄酱的流变特性更为合理. 相似文献
34.
35.
A specific, sensitive, precise, and accurate method for the determination of abscisic acid (ABA) in grapevine leaf tissues
is described. The method employs high-performance liquid chromatography and electrospray ionization–mass spectrometry (LC-ESI-MS)
in selected ion monitoring mode (SIM) to analyze ABA using a stable isotope-labeled ABA as an internal standard. Absolute
recoveries ranged from 72% to 79% using methanol/water pH 5.5 (50:50 v/v) as an extraction solvent. The best efficiency was
obtained when the chromatographic separation was carried out by using a porous graphitic carbon (PGC) column. The statistical
evaluation of the method was satisfactory in the work range. A relative standard deviation (RDS) of < 5.5% and < 6.0% was
obtained for intra-batch and inter-batch comparisons, respectively. As for accuracy, the relative error (%Er) was between
−2.7 and 4.3%, and the relative recovery ranged from 95% to 107%. 相似文献
36.
Martin Werth Ann-Kathrin Spiegel Marian Kazda 《Isotopes in environmental and health studies》2013,49(1):98-108
The transformation from self-supporting lianas to host-supported climbing lianas is related to re-allocation of biomass and nutrients among plant organs. Therefore, first, variations in leaf mass per area (LMA), leaf carbon and nitrogen allocation and 13C and 15N natural abundances were analysed among three tropical Passiflora species (P. edulis, P. ligularis, and P. tripartita) in a greenhouse study. Second, the influence of a climbing support was considered for each species and parameter. P. ligularis leaves were most enriched in 13C in both treatments when compared with the other two species. This enrichment was caused by a high LMA, which is related to a high internal resistance to CO2 diffusion. For P. edulis and P. tripartita, δ13C was additionally increasing with nitrogen content per area. Generally, there were no differences when considering carbon and nitrogen allocation to leaves of host-supported and self-supporting lianas. The only hints towards increased investment into leaves after the transition from self-supporting to host-supported stages could be seen by a trend to increased leaf areas and masses. δ13C values of supported P. edulis or P. tripartita plants were significantly increasing faster than those of non-supported plants once the interactions of leaf mass or nitrogen content per area were accounted for. Hence, the offer of a climbing support had only a minor impact on δ13C or δ15N values in vitro, but this could be different with increasing age of lianas in vivo. 相似文献
37.
Yongjing Liu Qiang Chen Suxia Zhang Hua Zhang Wei Xu 《Biomedical chromatography : BMC》2022,36(3):e5293
Deep eutectic solvents (DESs) were applied as eco-friendly solvents in this study for the extraction of alkaloids from lotus leaf, including O-nornuciferine, N-nornuciferine, nuciferine and roemerine. A series of hydrophilic and hydrophobic DESs with different hydrogen bond donors and a acceptors were synthesized and screened for a suitable DESs for extraction of alkaloids from lotus leaf. The study results showed that the hydrophilic DES with choline chloride and propanediol had the highest extraction yield. The main factors affecting the extraction efficiency—choline chloride–propanediol ratio, water content in deep eutectic solvents, solid–liquid ratio and extraction time—were investigated via a single-factor experiment. The optimized extraction conditions were 30% of water in choline chloride–propanediol (1:4) for heated extraction for 30 min and solid–liquid ratio 1:100 g/ml. Under optimum conditions, the extraction yields of O-nornuciferine, N-nornuciferine, nuciferine and roemerine were 0.069, 0.152, 0.334 and 0.041 g/100 g respectively, which were higher than those of methanol in acidified aqueous solution. This study suggests considerable potential for DESs as promising materials for the green and efficient extraction solvents for bioactive alkaloids from natural sources. 相似文献
38.
V. Sadanand N. Rajini B. Satyanarayana 《International Journal of Polymer Analysis and Characterization》2018,23(4):313-320
Cellulose/silver nanoparticle composite films with in situ-generated silver nanoparticles (AgNPs) were prepared using Ocimum sanctum leaf extract as a reducing agent in the absence and presence of sunlight and were characterized by SEM, FTIR, XRD, and antibacterial tests. Sunlight hastened up the preparation of these composite films. The average size of the in situ-generated AgNPs was reduced by the sunlight. The antibacterial activity and other properties of the composites were enhanced by the sunlight. The cellulose/AgNP composite films with improved properties by sunlight can be considered for medical purpose as antibacterial dressing materials. 相似文献
39.
Leaf and root extracts of Clerodendrum infortunatum L. have been reported to show anthelmintic efficacy on a cestode parasite Raillietina tetragona. Its leaf showed no toxicity at 1000 mg/kg body weight but root toxicity study was not known. Therefore, our study is to test both leaf and root extracts at 2000 and 3000 mg/kg body weight concentration given orally for 15 days in four groups of Swiss albino mice, keeping another set as control (without plant extract). Weight and behaviour of mice were recorded daily. Feeding, movement pattern were normal in all treatments as that of control. Though body weight increase, there was no change in the relative organ weight. Biochemical and haematological studies revealed no significant change from control and no alteration in histopathological study of liver and kidney from that of control. The plant extracts thus shown to be safe for consumption. 相似文献
40.
A remarkable theorem of E. Ghys asserts that, for any harmonic measure on a compact, foliated metric space, -almost every leaf has 0, 1, 2 or a Cantor set of ends. In this paper, analogous results are proven for topologically almost
all (i.e., residual families of) leaves. More precisely, if some leaf is totally recurrent, a residual family of leaves is
totally recurrent with 1, 2 or a Cantor set of ends. A "local" version of this theorem asserts that, in general, topologically
almost all leaves have 0, 1, 2 or a Cantor set of dense ends.
Received: October 1, 1997 相似文献