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排序方式: 共有171条查询结果,搜索用时 15 毫秒
1.
Anthony Blanchard Flavien Melis Fabrice Gouanvé Jean-Matthieu Brouillat Eliane Espuche 《Journal of polymer science. Part A, Polymer chemistry》2021,59(1):70-83
The influences of the molar mass (low, medium, and high) and content of poly(vinyl alcohol) (PVOH) dispersed by melt-blending in an ethylene vinyl alcohol (EVOH) copolymer on the morphology, microstructure, thermal, mechanical, and oxygen barrier properties were investigated. Multilayer films with external low-density polyethylene layers and inner EVOH/PVOH blend layer and respective monolayer films were elaborated and characterized. EVOH/PVOH blends exhibited a good compatibility because of the initial presence of PVOH segments in EVOH. The detailed quantitative analysis of the morphology performed for all blends showed that the finest dispersion was obtained with the PVOH with the lowest molar mass. The properties of the films as a function of the PVOH content and its molar mass were determined herein. Significant improvement of barrier properties was obtained at moderated water activities (up to aw = 0.6) by using the PVOH with the lowest molar mass. Compared to the neat EVOH material, the oxygen permeability coefficients decreased by a factor 2 by adding 15 vol% PVOH while the thermal and mechanical properties remained similar. 相似文献
2.
Josepha Yohanna de Jesus Eliane Santos de Carvalho Dantas Mairim Russo Serafini Paula dos Passos Menezes Juliana Cordeiro Cardoso Ricardo Luiz Cavalcanti Albuquerque-Jr Jivaldo do Rosário Matos Juliana Ferreira de Oliveira Irwin Rose Alencar de Menezes Francilene Amaral da Silva Adriano Antunes de Souza Araújo 《Journal of Thermal Analysis and Calorimetry》2016,123(3):2003-2012
3.
4.
Henri-Jean Cristau Amer Hammami Marc Taillefer Eliane Torreilles 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract The reaction of Ph3P-N-Li(12) with various α,β-unsaturated esters gives access to new N-(α,β-unsaturated acyl) phosphinimines. which can undergo intramolecular aza-Wittig reaction (at 65 - 110°C) to afford the corresponding nitriles. 相似文献
5.
Toward the Rational Design of Galactosylated Glycoclusters That Target Pseudomonas aeruginosa Lectin A (LecA): Influence of Linker Arms That Lead to Low‐Nanomolar Multivalent Ligands 下载免费PDF全文
Dr. Shuai Wang Lucie Dupin Mathieu Noël Cindy J. Carroux Dr. Louis Renaud Dr. Thomas Géhin Albert Meyer Dr. Eliane Souteyrand Dr. Jean‐Jacques Vasseur Dr. Gérard Vergoten Dr. Yann Chevolot Dr. François Morvan Dr. Sébastien Vidal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11785-11794
Anti‐infectious strategies against pathogen infections can be achieved through antiadhesive strategies by using multivalent ligands of bacterial virulence factors. LecA and LecB are lectins of Pseudomonas aeruginosa implicated in biofilm formation. A series of 27 LecA‐targeting glycoclusters have been synthesized. Nine aromatic galactose aglycons were investigated with three different linker arms that connect the central mannopyranoside core. A low‐nanomolar (Kd=19 nm , microarray) ligand with a tyrosine‐based linker arm could be identified in a structure–activity relationship study. Molecular modeling of the glycoclusters bound to the lectin tetramer was also used to rationalize the binding properties observed. 相似文献
6.
Eliane S. C. Temba Aluísio S. Reis Júnior Ângela Maria Amaral Roberto P. G. Monteiro 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(3):631-635
A methodology for the determination of 90Sr in low- and intermediate-level radioactive wastes from nuclear power plants is presented in this work. It is a part of
a methodology developed for the sequential radiochemical separation of radionuclides difficult-to-measure directly by gamma
spectrometry in these radioactive wastes. The separation procedure was carried out using precipitation and extraction chromatography
with Sr Resin, from Eichrom and the 90Sr was measured by liquid scintillation counting (LSC). Optimum conditions for the pretreatment, separation and LSC measurements
were determined using simulated samples, which were prepared using standard solutions and carriers. The procedure showed to
be rapid and achieved a good chemical yield, in the range 60–90%, and a detection limit of 6.0 × 10−4 Bq g−1. The method was also tested by participation in a national intercomparison program, with aqueous samples, with good agreement
of results. 相似文献
7.
Flavio Antonio Franchina Delphine Zanella Eliane Lazzari Pierre‐Hugues Stefanuto Jean‐Franois Focant 《Journal of separation science》2020,43(9-10):1790-1799
Headspace gas chromatography is frequently used for aroma profiling thanks to its ability to naturally exploit the volatility of aroma compounds, and also to provide chemical information on sample composition. Its main advantages rely on simplicity, no use of solvent, amenability to automation, and the cleanliness of the extract. In the present contribution, the most effective sampling (dynamic extraction), separation (multidimensional gas chromatography), and detection (mass spectrometry) techniques for untargeted analysis are exploited in combination, showing their potential in unraveling aroma profiles in fruit beers. To complete the overall analytical process, a neat workflow for data analysis is discussed and used for the successful characterization and identification of five different beer flavors (berries, cherry, banana, apple, and peach). From the technical viewpoint, the coupling of purge‐and‐trap, comprehensive two‐dimensional gas chromatography, and mass spectrometry makes the global methodology unique, and it is for the first time discussed. A (low‐)flow modulation approach allowed for the full transfer into the second dimension with mass‐spectrometry compatible flow (< 7 mL/min), avoiding the need of splitting before detection and making the overall method sensitive (1.2–5.2‐fold higher signal to noise ratio compared to unmodulated gas chromatography conditions) and selective. 相似文献
8.
9.
Eliane Gonçalves Gomes João Carlos Correia Baptista Soares de Mello Geraldo da Silva e Souza Lidia Angulo Meza João Alfredo de Carvalho Mangabeira 《Annals of Operations Research》2009,169(1):167-181
The aim of this paper is to use DEA models to evaluate sustainability in agriculture. Several variables are taken into account
and the resulting efficiency is measured by comparison. The performance of family farms is analysed here (variables: farmed
area, work force, and production). As agricultural sustainability depends on the maintenance of systems of production for
long periods of time, the models were run for the years of 1986 and 2002. Tiered DEA models were used to group farmers in
sustainability categories. Non-parametric regression models were used to identify the factors affecting the efficiency measurements.
All the results indicate that the majority of the farmers increased their efficiency along the time. These improvements may
support the existence of sustainability. 相似文献
10.