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排序方式: 共有109条查询结果,搜索用时 15 毫秒
31.
Sudib K. Mishra P.A. Deymier Krishna Muralidharan G. Frantziskonis Sreekanth Pannala Srdjan Simunovic 《Ultrasonics sonochemistry》2010,17(1):258-265
We introduce a model of cavitation based on the multiphase Lattice Boltzmann method (LBM) that allows for coupling between the hydrodynamics of a collapsing cavity and supported solute chemical species. We demonstrate that this model can also be coupled to deterministic or stochastic chemical reactions. In a two-species model of chemical reactions (with a major and a minor species), the major difference observed between the deterministic and stochastic reactions takes the form of random fluctuations in concentration of the minor species. We demonstrate that advection associated with the hydrodynamics of a collapsing cavity leads to highly inhomogeneous concentration of solutes. In turn these inhomogeneities in concentration may lead to significant increase in concentration-dependent reaction rates and can result in a local enhancement in the production of minor species. 相似文献
32.
33.
The chemical composition of the essential oils of Achillea clavennae L., Achillea holosericea Sibth. & Sm., Achillea lingulata W. & K., and Achillea millefolium L. from the Balkans was determined by GC and GC/MS analyses. The main components were 1,8-cineole in A. holosericea, camphor in A. clavennae, β-pinene in A. millefolium, and τ-cadinol in A. lingulata. A detailed chemotaxonomic discussion is presented.
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Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 555–558, November–December, 2005. 相似文献
34.
G. Stojanovic A. P. Ligon A. Smelcerovic J. Lazarevic M. Spiteller R. Palic 《Chemistry of Natural Compounds》2007,43(4):380-383
For the first time the total acid composition of the seeds of Stachys milanii Petrovic, a species endemic to the central and eastern Balkan Peninsula and growing spontaneously at two localities, was
examined by GC and GC/MS. The major fatty acid was linoleic or oleic acid. Besides fatty acids that represent the usual seed
oil constituents, 6-octadecynoic and 9-oxononanoic acid were identified in considerable amounts. The high content of 6-octadecynoic
acid makes S. milanii seed oil a good potential source for the active substance in antifungal preparations. From the chemotaxonomical point of
view, small amounts of octadecatrienoic acid detected in the seeds suggested classification of S. milanii as an archaic taxon.
Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 315–317, July–August, 2007. 相似文献
35.
We develop an approach to multivariable cubature based on positivity, extension, and completion properties of moment matrices. We obtain a matrix-based lower bound on the size of a cubature rule of degree 2n + 1; for a planar measure , the bound is based on estimating
where C:=C# [ ] is a positive matrix naturally associated with the moments of . We use this estimate to construct various minimal or near-minimal cubature rules for planar measures. In the case when C = diag(c1,...,cn) (including the case when is planar measure on the unit disk), (C) is at least as large as the number of gaps ck >ck+1. 相似文献
36.
J. Ruud van Ommen Srdjan Sasic John van der Schaaf Stefan Gheorghiu Filip Johnsson Marc-Olivier Coppens 《International Journal of Multiphase Flow》2011
This work reviews methods for time-series analysis for characterization of the dynamics of gas–solid fluidized beds from in-bed pressure measurements for different fluidization regimes. The paper covers analysis in time domain, frequency domain, and in state space. It is a follow-up and an update of a similar review paper written a decade ago. We use the same pressure time-series as used by Johnsson et al. (2000). The paper updates the previous review and includes additional methods for time-series analysis, which have been proposed to investigate dynamics of gas–solid fluidized beds. Results and underlying assumptions of the methods are discussed. 相似文献
37.
M.Cvetinov D.Z.Obadovic M.Stojanovic A.Vajda K.Fodor-Csorba N.Eber I.Ristic 《中国物理 B》2014,(9):341-346
In this work, five mixtures with different concentrations of banana-shaped and calamitic compounds have been prepared and subsequently studied by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction on non-oriented samples. The phase sequences and molecular parameters of the binary systems are presented. 相似文献
38.
Stefanie Drensler Srdjan Milenkovic Achim Walter Hassel 《Journal of Solid State Electrochemistry》2014,18(11):2955-2961
Nanostructured eutectic NiAl–W, fabricated using a Bridgman-type directional solidification facility, combines the advantages of single individual nanowires with the benefit of a conductive macroscopic matrix. Through an electrochemical dissolution step, using conditions derived from the combined Pourbaix diagrams of all three elements involved, the NiAl matrix is selectively dissolved allowing the release of embedded W nanowires. An application of micro-scale electrochemical techniques, such as scanning droplet cell microscopy, facilitates not only selective but moreover local matrix dissolution. Such a local dissolution leads to the formation of cavities on the micro-scale containing arrays of single crystalline W nanowires. In this connection, the depth and volume of fabricated microvials can directly be determined from the charge consumed during potentiostatic dissolution. A subsequent surface functionalisation enhances the hydrophobic behaviour, which is already observed for non-functionalised nanowire arrays, resulting in measured contact angles close to the border to superhydrophobicity. 相似文献
39.
Daniel Kogelnig Anja Stojanovic Markus Galanski Michael Groessl Franz Jirsa Regina Krachler Bernhard K. Keppler 《Tetrahedron letters》2008,49(17):2782-2785
New hydrophobic ionic liquids were synthesized from tricaprylmethylammonium chloride (Aliquat 336©) and selected Bronsted acids by a sustainable, simple and cost-saving deprotonation-metathesis route. Prepared ionic liquids were evaluated as potential extracting agents for cadmium from different aqueous solutions. High efficiency and selectivity were reached for the extraction of cadmium from a natural river matrix with tricaprylmethylammonium thiosalicylate, [A336][TS], a thiol-containing task specific ionic liquid. 相似文献
40.
Mirjana Stojanovic 《Mediterranean Journal of Mathematics》2013,10(4):1813-1831
Fractional derivatives of generalized stochastic processes have the global properties and keep the memory of their own. They are applicable for processes with memory. We employ them in solving equations driven by fractional derivatives of singular noises and singular initial data. We work on the perturbation of the wave equation by fractional time and space derivatives of generalized processes, in particular with Wiener process and a nonlinear term. The Wiener process is used to represent the integral of a Gaussian white noise process, and so is useful as a model of noise in electronics engineering, instrument errors in filtering theory and unknown forces in control theory. 相似文献