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151.
Dirk-Uwe Astrath Florian Lottes Duc Thoung Vu Wolfgang Arlt Erling H. Stenby 《Adsorption》2007,13(1):9-19
The efficiency of packed chromatographic columns was investigated experimentally by means of computed tomography (CT) techniques.
The measurements were carried out by monitoring tracer fronts in situ inside the chromatographic columns. The experimental
results were fitted using the equilibrium dispersive model (EDM) and varying the so called apparent axial dispersion coefficient.
The additivity of the first and second central moments was exploited to estimate column efficiency in different regions of
the column.
The results showed that the columns under investigation offered a higher column efficiency in the centre compared to the wall
region. Furthermore the void fraction in the vicinity of the walls was lower than that in the column core. For this reason
the bands were conveyed faster in the central region of the column where the permeability was higher. This result is in good
agreement with earlier findings. 相似文献
152.
Polarization labeling spectroscopy is applied to study the excited E(4)1Σ+ state of NaLi in the energy range 25 850-27 750 cm−1 above the bottom of the ground state. The potential curve of the E state is constructed using the Inverted Perturbation Approach method. 相似文献
153.
154.
We use the correspondence between hypergraphs and their associated edge ideals to study the minimal graded free resolution
of squarefree monomial ideals. The theme of this paper is to understand how the combinatorial structure of a hypergraph ℋ
appears within the resolution of its edge ideal ℐ(ℋ). We discuss when recursive formulas to compute the graded Betti numbers
of ℐ(ℋ) in terms of its sub-hypergraphs can be obtained; these results generalize our previous work (Hà, H.T., Van Tuyl, A.
in J. Algebra 309:405–425, 2007) on the edge ideals of simple graphs. We introduce a class of hypergraphs, which we call properly-connected, that naturally
generalizes simple graphs from the point of view that distances between intersecting edges are “well behaved.” For such a
hypergraph ℋ (and thus, for any simple graph), we give a lower bound for the regularity of ℐ(ℋ) via combinatorial information
describing ℋ and an upper bound for the regularity when ℋ=G is a simple graph. We also introduce triangulated hypergraphs that are properly-connected hypergraphs generalizing chordal
graphs. When ℋ is a triangulated hypergraph, we explicitly compute the regularity of ℐ(ℋ) and show that the graded Betti numbers
of ℐ(ℋ) are independent of the ground field. As a consequence, many known results about the graded Betti numbers of forests
can now be extended to chordal graphs.
Dedicated to Anthony V. Geramita on the occasion of his 65th birthday. 相似文献
155.
[ReOCl3(PPh3)2] and [Re(NPh)Br3(PPh3)2] react at room temperature with equivalent amounts of N,N‐dialkyl‐N′‐benzoylthioureas (HR1R2btu) in CH2Cl2 under formation of the rhenium(V) complexes [ReOCl2(R1R1btu)(PPh3)] and [Re(NPh)Br2(R1R2btu)(PPh3)], respectively. The products are structurally analogous with the oxygen atoms of the benzoylthioureas binding in trans positions to the oxo or phenylimido ligands. Prolonged reaction times result in the reduction of the oxo compound by the released PPh3 and the formation of rhenium(III) complexes of the composition [ReCl2(PPh3)2(R1R2btu)], while such a second reaction path is excluded for the phenylimido compound. Phenylimido species with more than one N,N‐dialkyl‐N′‐benzoylthioureato ligand could not be isolated, even when a large excess of HR1R2btu was used during the reaction. 相似文献
156.
Vu Kuok Fong 《Ukrainian Mathematical Journal》1988,40(1):94-97
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 40, No. 1, pp. 110–113, January–February, 1988. 相似文献
157.
158.
Pham Huy Dien 《Applied Mathematics and Optimization》1985,13(1):151-161
This paper deals with a regularity assumption for the existence of Lagrange Multipliers for an optimization problem in Hilbert spaces. First some results of [6] are extended; then a class of discrete systems in a Hilbert Space is considered where the regularity assumption automatically holds and the Discrete Maximum Principle is obtained.This research was partly supported by the Computer and Automation Institute of the Hungarian Academy of Sciences. 相似文献
159.
160.