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21.
J.F. Carballido Quesada A. de la Villa Cuenca 《International Journal of Mathematical Education in Science & Technology》2013,44(6):909-912
This paper is divided into two distinct but connected parts. In the first one we look for the best approach to the Mathematics teaching of the future engineer. This approach should have an eminently pragmatic character and should be directed towards teaching engineers to know and manage Mathematics at a tool. In the second part we illustrate how a collaboration with industry can be obtained from this kind of teaching. Finally the conditions and consequences which should produce this cooperation are analysed, and some particular examples are mentioned. 相似文献
22.
David Alonso-Gutiérrez Bernardo González Merino C. Hugo Jiménez Rafael Villa 《Journal of Geometric Analysis》2018,28(2):1182-1201
We extend the notion of John’s ellipsoid to the setting of integrable log-concave functions. This will allow us to define the integral ratio of a log-concave function, which will extend the notion of volume ratio, and we will find the log-concave function maximizing the integral ratio. A reverse functional affine isoperimetric inequality will be given, written in terms of this integral ratio. This can be viewed as a stability version of the functional affine isoperimetric inequality. 相似文献
23.
Biomass conversion has been developed by testing various metal based carbon catalysts. Most of the reported catalysts either use very expensive metals or support that provides lower selectivity. In this context, we fabricated new carbon based nanocomposites and studied their catalytic application for furfural reduction – a promising biomass derived molecule. The mono (Cu, Co and Ni) and bimetallic (CuCo and CuNi) nanoparticle supported on commercial graphite (CG) were prepared and characterized by TEM, EDS, XRD and Raman spectroscopy. The analysis revealed that the nanocomposites are made up of metallic nanoparticles with average particle size of 5–13 nm on the graphite matrix. The obtained results indicated that the Cu+Ni@CG catalyst exhibited high catalytic activity for furfural reduction, thus leaving Cu+Ni as the finest and cost effective catalyst for this study. 相似文献
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Villa de P AL Alarcón E Montes de Correa C 《Chemical communications (Cambridge, England)》2002,(22):2654-2655
MCM-41 was found to be an active heterogeneous catalyst for the synthesis of nopol by the Prins condensation of beta-pinene and paraformaldehyde, but Sn-MCM-41 in which Sn has been grafted on MCM-41 by chemical vapor deposition is far more active and combines high efficiency and recyclability. 相似文献
26.
Vistoli G Pedretti A Villa L Testa B 《Journal of the American Chemical Society》2002,124(25):7472-7480
The objective of this study was to determine if and how a solvent influences internal motions in a solute molecule. Acetylcholine was chosen as the object of study given its interesting molecular structure and major biological significance. Molecular dynamics simulations were carried out in the vacuum (10 ns), water (5 ns), methanol (5 ns), and octanol (1.5 ns). Seven clusters of conformers were identified, namely, +g+g, -g-g, +gt, -gt, t+g, t-g, and tt, where the gauche and trans labels refer to the dihedral angles tau(2) and tau(3), respectively. As expected, the relative proportion of these conformational clusters was highly solvent-dependent and corresponded to a progressive loss of conformational freedom with increasing molecular weight of the solvent. More importantly, the conformational clusters were used to calculate instantaneous and median angular velocity (omega and omega(M), respectively) and instantaneous and median angular acceleration (alpha and alpha(M), respectively). Angular velocity and angular acceleration were both found to decrease markedly with increasing molecular weight of the solvent, i.e., vacuum (epsilon = 1) > water > methanol > octanol. The decrease from the vacuum to octanol was approximately 40% for tau(2) and approximately 60% for tau(3). Such solvent-dependent constraints on a solute's internal motions may be biologically and pharmacologically relevant. 相似文献
27.
Tetko IV Aksenova TI Volkovich VV Kasheva TN Filipov DV Welsh WJ Livingstone DJ Villa AEP 《SAR and QSAR in environmental research》2000,11(3-4):263-280
This article presents a self-organising multilayered iterative algorithm that provides linear and non-linear polynomial regression models thus allowing the user to control the number and the power of the terms in the models. The accuracy of the algorithm is compared to the partial least squares (PLS) algorithm using fourteen data sets in quantitative-structure activity relationship studies. The calculated data show that the proposed method is able to select simple models characterized by a high prediction ability and thus provides a considerable interest in quantitative-structure activity relationship studies. The software is developed using client-server protocol (Java and C++ languages) and is available for world-wide users on the Web site of the authors. 相似文献
28.
P. Forzatti P. L. Villa D. Ercoli G. Ercoli F. Gasparini und F. Trifiro 《Colloid and polymer science》1978,256(8):831
Ohne Zusammenfassung 相似文献
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R. Jimnez M. Villar M. Cueto E. Grueso J. Illanes J. I. Cobrian F. Cantn I. Villa J. M. Snchez S. Maza J. M. Muoz C. Muoz R. Prado‐Gotor 《国际化学动力学杂志》2004,36(7):410-415
The base‐catalyzed linkage isomerization of [Co(NH3)5‐ONO]2+ to the nitro [(NH3)5Co‐NO2]2+ form is studied in various isodielectric water–cosolvent mixtures (methanol, ethanol, tert‐butyl alcohol, and 2‐propanol) at 298 K. In all cases, except for methanol–water mixtures, the rate constants increase with the proportion of cosolvent. Medium effects have been rationalized by using a multiparameter regression of solvent parameters which rationalizes the results obtained, including water–methanol mixtures. The experimental data, k2, in fact, are well correlated through the following equation: where A, B, and Gexc are the acidity parameter, the basicity parameter, and the excess Gibbs free energy of the mixture, respectively. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 410–415, 2004 相似文献