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排序方式: 共有1264条查询结果,搜索用时 15 毫秒
61.
Caio Machado Fernandes Marcos Vinícius Palmeira de Mello Nazir Escarpini dos Santos Alessandra Mendonça Teles de Souza Mauricio Lanznaster Eduardo Ariel Ponzio 《工业材料与腐蚀》2020,71(2):280-291
4-Chloro-N-(pyridin-2-ylmethyl)aniline (CPYA) was synthesized by a simple and inexpensive method and tested as a corrosion inhibitor in acid medium for mild steel by using gravimetric studies and electrochemical measurements. An average maximum efficiency of 96.0% was achieved at 4.59 mmol/L. Corrosion kinetic and thermodynamic parameters were also analyzed. Surface analyses (atomic force microscopy and scanning electron microscopy) show that protection is enabled by adsorption on the metal, forming a film. Quantum chemical calculations were performed to access information regarding the molecular structure in the corrosive medium and to support interpretation of the results obtained by experimental methods. 相似文献
62.
A Procedure for Evaluating the Compatibility of Surface Water Resources with Environmental and Human Requirements 总被引:1,自引:0,他引:1
Marco Franchini Ernesto Ventaglio Alessandra Bonoli 《Water Resources Management》2011,25(14):3613-3634
This paper presents a novel and easy-to-use procedure for controlling and licensing water abstractions from a river based on establishing a balance between surface water resources and environmental and human requirements. Unlike other approaches relying on complex and detailed basin models, this is based simply on the use of the discharge duration curve to represent the available water resources. In particular, the scheme of analysis presented here is composed of four steps: 1) subdivision of a particular river reach into sub-reaches; 2) estimation of the availability of water along each sub-reach over a particular period of time by means of duration curves; 3) estimation of the environmental requirements (minimum instream flow—MIF) and quantities necessary for civil, agricultural and industrial uses over the same period, and 4) establishing a water balance model for each sub-reach, taking into consideration the effects produced by water resource use in the upstream sub-reaches. In particular, this procedure consents (a) quantification of the duration when abstractions are possible along each sub-reach, (b) quantification of the maximum abstraction needed to satisfy the volume requested (thereby enabling comparison with the amount the users can actually obtain through their structures and/or pumps) and (c) identification of situations in which users need to avail themselves of reservoirs for temporarily storing the water abstracted so that they do not exceed the availability on non-abstraction days. The procedure was successfully applied to a basin located in Emilia-Romagna, the Enza River, along which 9 sub-reaches were identified. 相似文献
63.
Phenotypic and genotypic characterization of Oenococcus oeni strains isolated from Italian wines 总被引:3,自引:0,他引:3
Guerrini S Bastianini A Blaiotta G Granchi L Moschetti G Coppola S Romano P Vincenzini M 《International journal of food microbiology》2003,83(1):1-14
A phenotypic and genotypic characterization of 84 Oenococcus oeni isolates from Italian wines of different oenological areas was carried out. Numerical analysis of fatty acid profiles grouped the isolates into two clusters at low level of similarity (63%), the minor cluster containing seven isolates besides the type and the reference strains. Forthy-eight O. oeni isolates, representative of the two clusters, showed no differences in their metabolic properties (heterolactic fermentation pattern, citrate degradation capability and formation of some secondary metabolites). Moreover, the analysis of species-specific randomly amplified polymorphic DNA and 16S-23S rDNA intergenic spacer region polymorphism as well as the sequence-specific separation of V3 region from 16S rDNA by denaturing gradient gel electrophoresis demonstrated a substantial homogeneity among the isolates. On the basis of ApaI Pulsed Field Gel Electrophoresis (PFGE) restriction patterns, the 84 isolates were grouped into five different clusters at 70% similarity, but no correlation with the phenotypic groups could be demonstrated. However, by combining phenotypic and genotypic data, the 84 O. oeni isolates grouped into eight phenotypic-genotypic combined profiles and a relationship between the origin of the isolates and their combined profile became evident, so that a sort of strain specificity can be envisaged for each wine-producing area. 相似文献
64.
Daniel El Chami Maroun El Moujabber Alessandra Scardigno 《Water Resources Management》2009,23(11):2361-2378
The Lebanese coast is highly subject to seawater intrusion and groundwater deterioration. The study is carried out in Byblos
district (Jbeil Caza) 35 km north of Beirut. It aims to investigate the seawater intrusion, to determine the regional water
balance of the region and finally to estimate the economic value of that water for agricultural use. The monitoring of the
aquifer was achieved through samples from different wells chosen randomly. As for the regional water balance, it was determined
with use of a GIS model. The economic evaluation was carried out, using the contingent valuation method to estimate the willingness
to pay of farmers to contribute to the improvement of groundwater quality; two alternative scenarios were proposed and compared
with the current situation. The annual regional water balance is positive, which means that the region is rich in water. The
monitoring results show that the coastal part of the region is slightly contaminated by seawater intrusion due to the excess
of pumping from the aquifer. The economic evaluation estimated that farmers would contribute by 102 US$ yr − 1 for the first proposal and 166.67 US$ yr − 1 for the second. 相似文献
65.
Hybrid Organic/Inorganic Nanostructures for Highly Sensitive Photoelectrochemical Detection of Dissolved Oxygen in Aqueous Media 下载免费PDF全文
Sebastiano Bellani Ali Ghadirzadeh Laura Meda Alberto Savoini Alessandra Tacca Gianluigi Marra Rui Meira Jorge Morgado Fabio Di Fonzo Maria Rosa Antognazza 《Advanced functional materials》2015,25(28):4531-4538
Precise, reliable, and remote measurement of dissolved oxygen in aqueous media is of great importance for many industrial, environmental, and biological applications. In particular, photoelectrochemical sensors working in differential mode have recently demonstrated promising properties, in terms of stability, sensitivity, and application potential. Here, a new approach is presented, combining visible light sensitivity, efficient photocurrent generation, and solution‐processed fabrication methods of conjugated polymers, with charge carriers selectivity, energetic alignment favorable to efficient interfacial charge transfer and high surface area achievable by using metal oxide nanostructures. Extensive characterization and optimization of the hybrid organic/inorganic system are carried out, leading to the realization of an oxygen sensor device, based on nanostructured palladium oxide/poly[(9,9‐dioctylfluorenyl‐2,7‐diyl)‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole]/[6,6]phenyl‐C61‐butyric acid methyl ester (PdO/APFO‐3:PCBM) as materials of choice. State‐of‐the‐art sensitivity, amounting at ?5.87 μA cm?2 ppm?1, low background signal, in the order of ?4.85 μA cm?2, good electrochemical stability for more than 2 h of continuous functioning and high reproducibility of the signal over the pH 1 to 10 range, are reported, making the hybrid device suitable for several practical uses. The results fully validate the mixed organic/inorganic approach for photoelectrochemical applications, and pave the way for its further exploitation in fields like waste water treatment, environmental monitoring, and water splitting. 相似文献
66.
The problem addressed in this paper concerns the complexity reduction of the nearest feature plane classifier, so that it may be applied also in dataset where the training set contains many patterns. This classifier considers, to classify a test pattern, the subspaces created by each combination of three training patterns. The main problem is that in dataset of high cardinality this method is unfeasible.A genetic algorithm is here used for dividing the training patterns in several clusters which centroids are used to build the feature planes used to classify the test set.The performance improvement with respect to other nearest neighbor based classifiers is validated through experiments with several benchmark datasets. 相似文献
67.
68.
Chiara Renghini Alessandra Giuliani Serena Mazzoni Francesco Brun Emanuel Larsson Francesco Baino Chiara Vitale-Brovarone 《Journal of the European Ceramic Society》2013,33(9):1553-1565
One of the key purposes of bone tissue engineering is the development of new biomaterials that can stimulate the body's own regenerative mechanism for patient's anatomical and functional recovery. Bioactive glasses, due to their versatile properties, are excellent candidates to fabricate porous 3-D architectures for bone replacement. In this work, morphological and structural investigations are carried out on Bioglass®- and CEL2-derived scaffolds produced by sponge replication (CEL2 is an experimental glass developed at Politecnico di Torino). Synchrotron radiation X-ray microtomography is used to study the samples 3-D architecture, pores size, shape, distribution and interconnectivity, as well as the growth kinetics on scaffolds struts of a newly formed apatitic phase during in vitro treatment in simulated body fluid, in order to describe from a quantitative viewpoint the bioactive potential of the analyzed biomaterials. An accurate comparison between architectural features and bioactive behaviour of Bioglass®- and CEL2-derived scaffolds is presented and discussed. 相似文献
69.
Silvia Francesca Storti Emanuela Formaggio Deborah Moretto Alessandra Bertoldo Francesca Benedetta Pizzini Alberto Beltramello Antonio Fiaschi Gianna Maria Toffolo Paolo Manganotti 《Magma (New York, N.Y.)》2014,27(2):171-184
Objective
Among other neuroimaging techniques, functional magnetic resonance imaging (fMRI) can be useful for studying the development of motor fatigue. The aim of this study was to identify differences in cortical neuronal activation in nine subjects on three motor tasks: right-hand movement with minimum, maximum, and post-fatigue maximum finger flexion.Materials and methods
fMRI activation maps for each subject and during each condition were obtained by estimating the optimal model of the hemodynamic response function (HRF) out of four standard HRF models and an individual-based HRF model (ibHRF).Results
ibHRF was selected as the optimal model in six out of nine subjects for minimum movement, in five out of nine for maximum movement, and in eight out of nine for post-fatigue maximum movement. As compared to maximum movement, a large reduction in the total number of active voxels (primary sensorimotor area, supplementary motor area and cerebellum) was observed in post-fatigue maximum movement.Conclusion
This is the first approach to the evaluation of long-lasting contraction effort in healthy subjects by means of the fMRI paradigm with the use of an individual-based hemodynamic response. The results may be relevant for defining a baseline in future studies on central fatigue in patients with neuropathological disorders. 相似文献70.
A comprehensive investigation of dye–chitosan blended films for green chemistry applications 下载免费PDF全文
Vito Rizzi Alessandra Longo Tiziana Placido Paola Fini Jennifer Gubitosa Teresa Sibillano Cinzia Giannini Paola Semeraro Esther Franco Marcela Ferrandiz Pinalysa Cosma 《应用聚合物科学杂志》2018,135(10)
In this paper, the ability of chitosan film to remove dyestuff from wastewater was evaluated for environmental applications, using three commercial direct azo dyes. Two chitosan films were adopted: the standard one prepared following a well‐known procedure to form it, and a novel one, with a weakly acidic character. Moreover, to improve the adsorption process, the hydrophobic character of the films was investigated. The pH of the dye solutions was also changed, showing an excellent ability in dye removal at pH 12. The films were characterized by means of spectroscopic and morphologic methods to better understand the nature of interactions between dyes and chitosan chains. Swelling ratio measurements were also performed. All analyses suggest that all dyes showed a strong affinity to chitosan polymer chains, with the presence of extended hydrogen bonds and Van der Waals forces perturbing the chitosan network. Interestingly, very good results were obtained in recycling experiments related to the dyeing capacities of chitosan blended films in the presence of textiles. An ecofriendly application is thus presented in this paper. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45945. 相似文献