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111.
In complex domains it is usually quite difficult to introduce context information. However, sometimes that information should be taken into account to make decisions, because it provides some relevant knowledge that cannot be expressed using an attribute-value representation. This is the case of the determination of risk of contamination of soils. In this paper, we propose to use conjunctive rules to introduce additional background knowledge to a MCDM sorting method called ClusDM. ClusDM is based on the aggregation of the data with unsupervised clustering techniques. The paper presents a new algorithm to incorporate rules to guide the clustering process in a semi-supervised way. The paper also describes how it works in the case sorting a set of possible contaminated soils, and compares the results obtained by ClusDM when rules are used or not. 相似文献
112.
Montserrat Alfonso Antonia Neels Helen Stoeckli-Evans 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(10):1144-1146
The new nickel(II) coordination polymer poly[diaquanickel(II)-μ-(pyrazine-2,3,5,6-tetracarboxylato)-tetraaquanickel(II)], {[{Ni(C8N2O8)(H2O)2}Ni(H2O)4]}n, has been synthesized and characterized both spectroscopically and crystallographically, by X-ray powder diffraction analysis. In this two-dimensional coordination polymer, NiII ions are bridged by pyrazine-2,3,5,6-tetracarboxylic acid, coordinating in a bis-bidentate manner, so forming one-dimensional polymeric chains. The chains are linked by a second NiII ion, via an O atom of the coordinated carboxylate group, resulting in the formation of a two-dimensional layer-like polymer. The remaining coordination sites of the two independent octahedral NiII ions are occupied by water molecules. The layers are connected via hydrogen bonds involving all six coordinated water molecules. 相似文献
113.
Montserrat Corbera Jaume Llibre Ernesto Pérez-Chavela 《Journal of Mathematical Analysis and Applications》2014
In this paper we prove the existence of two new families of spatial stacked central configurations, one consisting of eight equal masses on the vertices of a cube and six equal masses on the vertices of a regular octahedron, and the other one consisting of twenty masses at the vertices of a regular dodecahedron and twelve masses at the vertices of a regular icosahedron. The masses on the two different polyhedra are in general different. We note that the cube and the octahedron, the dodecahedron and the icosahedron are dual regular polyhedra. The tetrahedron is itself dual. There are also spatial stacked central configurations formed by two tetrahedra, one and its dual. 相似文献
114.
115.
A. Bensouici V. Carcelen J.L. Plaza S. De Dios N. Vijayan J. Crocco H. Bensalah E. Dieguez M. Elaatmani 《Journal of Crystal Growth》2010,312(14):2098-2102
The effect of surface preparation on CdZnTe properties was investigated. Surface etching using bromine solutions enhances Te elemental composition, resulting in a Te rich surface layer that is prone to oxidize. This oxidation degrades the performance of the fabricated CZT gamma detector. Roughness results were identical for samples polished with 1 and 3 μm and subsequently etched in 2% Br-MeOH. The optimal concentration of etching was 2% Br-MeOH. 相似文献
116.
Simon Woodward Montserrat Diéguez Oscar Pàmies 《Coordination chemistry reviews》2010,254(17-18):2007-2030
This review describes recent development in the use of sugar-derived ligands in the selective synthesis of organic molecules. Developments in the recent literature (2004–2009) are highlighted in the areas of hydrogenation, 1,2- and 1,4-additions of nucleophiles to CO and CNR based substrates, cross-coupling, hydroformylation, oxidation and other reactions. Connections to earlier studies are also noted were relevant. Some suggestions as to the underlying features that make sugar-based ligands highly useful modular ligands in selective catalysis are given. Finally, advice is presented (for the non-specialist) on optimal entry points and basic starting materials for sugar-ligand synthesis. 相似文献
117.
This research paper presents a comparative study of two different extraction and concentration techniques to obtain representative pistachio aroma extracts: the traditional direct solvent extraction (DSE) followed by high-vacuum transfer (HVT) and the headspace solid-phase microextraction (HS-SPME). The results showed that, although both techniques provide accurate information about the aromatic composition that will be perceived by the consumer, the precision in terms of within-day repeatability and between-days repeatability (intermediate precision) of the chromatographic areas presented better values for HS-SPME than for DSE-HVT. Moreover the solvent-free HS-SPME allows the extraction of more odour-active regions, requires very little sample handling and shorter time for sampling. 相似文献
118.
Pàmies O Andersson PG Diéguez M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(48):14232-14240
This account discusses the progress made in the asymmetric hydrogenation of minimally functionalised terminal olefins as a new, alternative, sustainable and direct strategy for preparing enantioenriched hydrocarbons. It discusses the latest development in catalyst design, from the initial discovery of lanthanide catalytic precursors, through the use of transition-metal/diphosphine-iminophosphorane precursors, to the successful iridium/P,N catalytic systems. 相似文献
119.
Abd‐Elgawad Radi Xavier Muoz‐Berbel Montserrat Cortina‐Puig Jean‐Louis Marty 《Electroanalysis》2009,21(6):696-700
A novel protocol for immobilization of horseradish peroxidase (HRP) onto diazonium functionalized screen‐printed gold electrode (SPGE) has been successfully developed. This protocol involved 1) electrochemical reduction of p‐nitrophenyl diazonium salts synthesized in situ in acidic aqueous solution to graft a layer of p‐nitrophenyl on SPGE, 2) electrochemical reduction of the nitro groups to convert to amines, 3) chemical reaction with nitrous acid to transform the amine to diazonium derivative and 4) chemical coupling of the enzyme with the diazonium group to form a covalent diazo bond. The fabricated biosensor showed the direct electrochemistry of HRP and displayed electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2) without any mediator. The biosensor exhibited fast amperometric response to H2O2. The catalytic current increased with increasing H2O2 concentration from 5 μM to 30 μM and the detection limit of the biosensor was 2 μM. The biosensor exhibited acceptable sensitivity, good reproducibility and long‐term stability. 相似文献
120.
Ying Wang Carole Calas‐Blanchard Montserrat Cortina‐Puig Liu Baohong Jean‐Louis Marty 《Electroanalysis》2009,21(12):1395-1400
A simple and sensitive electrochemical method for the determination of antioxidant capacity has been studied. 4‐hydroxybenzoic acid (4‐HBA) was used as a trapping agent for photogenerated .OH radicals, leading to 3,4‐dihydroxybenzoic acid (3,4‐DHBA). Square‐wave voltammetry was used to quantify the amount of 3,4‐DHBA formed from the reaction between 4‐HBA and .OH. Addition of antioxidants induced the competition between 4‐HBA and antioxidants toward .OH elimination, resulting in a decrease of the measured current. The IC50 for different standard antioxidants was calculated and expressed in Trolox equivalent antioxidant capacity (TEAC). The proposed method was successfully compared to a fluorimetric one. 相似文献