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701.
We investigate the filtration law of incompressible viscous Newtonian fluids in rigid non-inertial porous media, for example, rotating porous media. The filtration law is obtained by upscaling the flow at the pore scale. We use the method of multiple scale expansions which gives rigorously the macroscopic behaviour without any prerequisite on the form of the macroscopic equations. For finite Ekman numbers the filtration law is shown to resemble a Darcy's law, but with a non-symmetric permeability tensor which depends on the angular velocity of the porous matrix. We obtain the filtration analog of the Hall effect. For large Ekman numbers the filtration law is a small correction to the classical Darcy's law. The corrector is antisymmetric. In this case we recover a structure of law which is similar to phenomenological laws introduced in the literature, but with a dissimilar effective coefficient. 相似文献
702.
Jean-Louis Calais 《物理学进展》2013,62(6):847-885
The article is a review of band-structure calculations for transition metal compounds (carbides and nitrides, layer compounds, A15 structures, and others). 相似文献
703.
During our research on novel, non-traditional, bicyclic β-lactams as potential inhibitors of Penicillin Binding Proteins (PBPs), we focused on the synthesis of 1,3-bridged 2-azetidinones by RCM reaction from 1,3-bis-ω-alkenoyl-3(S)-amino-2-azetidinone precursors. Submitting the precursors to RCM, we faced an unexpected problem: cyclodimerization was the preferred outcome. This peculiar reactivity, explained by a computational study, led to unprecedented bis-azetidinyl-macrocycles acting as potent inhibitors of R39 D,D-carboxypeptidase, a bacterial model enzyme for PBPs. 相似文献
704.
Pure mixed triglycerides can be prepared from diglycerides and by acylolysis of glycerolformal tosylate without isomerization. The last fatty chain, with or without a functional group, can be introduced on any position of glycerol. 相似文献
705.
Zuleyka MENDEZ Raquel E. ANTON Jean-Louis SALAGER 《Journal of Dispersion Science and Technology》2013,34(3):883-892
Surfactant-oil-water systems in which the surface active substance is a mixture of carboxylic acid and its sodium salt (soap), exhibit emulsion property maps that are consistent with the phase behavior and the general emulsion phenomenology. However they present specific features such as an extended C+ multiple emulsion region and a skinked A+ W/O emulsion zone. In this case the aqueous phase pH drives the relative hydrophilicity of the acid/salt mixture at interface and plays the role of the most sensitive formulation variable. Studied systems contain C10 to C14 carboxylic acid, NaCl brine and a light distillation cut, as well as alcohols. 相似文献
706.
Pierre Hansen Jean-Louis Lagouanelle Frédéric Messine 《Journal of Global Optimization》2007,37(2):215-228
Two ways for bounding n-variables functions over a box, based on interval evaluations of first order derivatives, are compared. The optimal Baumann form gives the best lower bound using a center within the box. The admissible simplex form, proposed by the two last authors, uses point evaluations at n + 1 vertices of the box. We show that the Baumann center is within any admissible simplex and can be represented as a linear convex combination of its vertices with coefficients equal to the dual variables of the
linear program used to compute the corresponding admissible simplex lower bound. This result is applied in a branch-and-bound
global optimization and computational results are reported. 相似文献
707.
tienne Houz Jean-Louis Dessalles Ada Diaconescu David Menga 《Entropy (Basel, Switzerland)》2022,24(3)
With the increasing number of connected devices, complex systems such as smart homes record a multitude of events of various types, magnitude and characteristics. Current systems struggle to identify which events can be considered more memorable than others. In contrast, humans are able to quickly categorize some events as being more “memorable” than others. They do so without relying on knowledge of the system’s inner working or large previous datasets. Having this ability would allow the system to: (i) identify and summarize a situation to the user by presenting only memorable events; (ii) suggest the most memorable events as possible hypotheses in an abductive inference process. Our proposal is to use Algorithmic Information Theory to define a “memorability” score by retrieving events using predicative filters. We use smart-home examples to illustrate how our theoretical approach can be implemented in practice. 相似文献
708.
709.
本文采用超导量子干涉仪(SQUID)测定了一种国际热核聚变实验堆(ITER)项目用内锡法Nb3Sn超导线材的不可逆温度,测量方法是在恒定磁场下循环温度,即将温度以一定间隔从10K上升到20K,然后再返回到10K,测定磁矩的偏离温度.所得结果可用于从生成最佳Nb-Sn相组成方面来优化A15相成相热处理制度.本研究得出的结论是,对于像ITER使用的高场磁体超导线来说,鉴于其需要在较高磁场下有高的临界电流密度,就需要将超导线的热处理温度适当提高一些.本实验所用Nb3Sn超导线材的最适宜热处理制度为675°C/128小时,这样可以得到最佳不可逆温度特性,即最佳的A15相组成. 相似文献
710.
Let n = n1 + n2 + … + nj a partition Π of n. One will say that this partition represents the integer a if there exists a subsum nil + ni2 + … + nil equal to a. The set
(Π) is defined as the set of all integers a represented by Π. Let
be a subset of the set of positive integers. We denote by p(
,n) the number of partitions of n with parts in
, and by
((
,n) the number of distinct sets represented by these partitions. Various estimates for
(
,n) are given. Two cases are more specially studied, when
is the set {1, 2, 4, 8, 16, …} of powers of 2, and when
is the set of all positive integers. Two partitions of n are said to be equivalent if they represent the same integers. We give some estimations for the minimal number of parts of a partition equivalent to a given partition. 相似文献