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761.
Vasileios Tzitzios Nikolaos Kostoglou Maria Giannouri Georgia Basina Christos Tampaxis Georgia Charalambopoulou Theodore Steriotis Kyriaki Polychronopoulou Charalambos Doumanidis Christian Mitterer Claus Rebholz 《International Journal of Hydrogen Energy》2017,42(37):23899-23907
A nanoporous metal–organic framework material, exhibiting an IRMOF-1 type crystalline structure, was prepared by following a direct solvothermal synthesis approach, using zinc nitrate and terephthalic acid as precursors and dimethylformamide as solvent, combined with supercritical CO2 activation and vacuum outgassing procedures. A series of advanced characterization methods were employed, including scanning electron microscopy, Fourier-transform infrared radiation spectroscopy and X-ray diffraction, in order to study the morphology, surface chemistry and structure of the IRMOF-1 material directly upon its synthesis. Porosity properties, such as Brunauer–Emmet–Teller (BET) specific area (~520 m2/g) and micropore volume (~0.2 cm3/g), were calculated for the activated sample based on N2 gas sorption data collected at 77 K. The H2 storage performance was preliminary assessed by low-pressure (0–1 bar) H2 gas adsorption and desorption measurements at 77 K. The activated IRMOF-1 material of this study demonstrated a fully reversible H2 sorption behavior combined with an adequate gravimetric H2 uptake relative to its BET specific area, thus achieving a value of ~1 wt.% under close-to-atmospheric pressure conditions. 相似文献
762.
Andi K. Winterboer Martin I. Tietze Maria K. Wolters Johanna D. Moore 《Computer Speech and Language》2011,25(2):175-191
A common task for spoken dialog systems (SDS) is to help users select a suitable option (e.g., flight, hotel, and restaurant) from the set of options available. As the number of options increases, the system must have strategies for generating summaries that enable the user to browse the option space efficiently and successfully. In the user-model based summarize and refine approach (UMSR, Demberg and Moore, 2006), options are clustered to maximize utility with respect to a user model, and linguistic devices such as discourse cues and adverbials are used to highlight the trade-offs among the presented items. In a Wizard-of-Oz experiment, we show that the UMSR approach leads to improvements in task success, efficiency, and user satisfaction compared to an approach that clusters the available options to maximize coverage of the domain (Polifroni et al., 2003). In both a laboratory experiment and a web-based experimental paradigm employing the Amazon Mechanical Turk platform, we show that the discourse cues in UMSR summaries help users compare different options and choose between options, even though they do not improve verbatim recall. This effect was observed for both written and spoken stimuli. 相似文献
763.
Ludovina R. Galego José P. Da Silva Valentim R. Almeida Maria R. Bronze Luís V. Boas 《International Journal of Food Science & Technology》2011,46(1):67-73
This work describes the preparation of aromatised liquors using deodorised and concentrated fruit distillates. The raw spirits were improved by making a partial deodorisation, using activated charcoal, followed by concentration, using a distiller. The liquors were prepared by a maceration process. The procedure is exemplified using fig distillates to prepare myrtle berry liquors. The acidity, copper, polyphenol and anthocyanin indexes and volatile and anthocyanin profiles were monitored in each preparation step. The concentration process increased the ethanol proof to 75% v/v and decreased the acidity and the copper content. The partial deodorisation decreased the levels of high molecular weight volatiles, while the content of lower molecular weight compounds that contribute to flavour was maintained. Delphinidin‐3‐O‐glucoside, cyanidin‐3‐O‐glucoside, petunidin‐3‐O‐glucoside and malvidin‐3‐O‐glucoside were the major anthocyanins. 相似文献
764.
Alessandro Abbotto Erika Herrera Calderon Norberto Manfredi Claudio Maria Mari Chiara Marinzi Riccardo Ruffo 《Synthetic Metals》2011,161(9-10):763-769
Vinylene-linked donor–acceptor–donor semiconducting polymers have been prepared by electropolymerization of the new monomers 2,6-bis[(E)-2-(1-methylpyrrol-2-yl)vinyl]pyridine and 2,5-bis[(E)-2-(1-methylpyrrol-2-yl)vinyl]pyridine. The monomers, consisting of two pyrrole donor units and a central pyridine acceptor ring spaced by vinylene links, differ by the substitution pattern around the central pyridine core (2,6 vs. 2,5-substitution). The electropolymerization process is more efficient on the 2,5-derivative. The new polymers show reversible electrochemistry dominated by a strong charge trapping effect. Poly(2,5-bis[(E)-2-(1-methylpyrrol-2-yl)vinyl]pyridine) energy levels closely match those of design rules for optimized polymers in combination with fullerene derivatives in bulk heterojunction solar cells. 相似文献
765.
766.
767.
Mariana‐Dana Damaceanu Radu‐Dan Rusu Alina Nicolescu Maria Bruma Alexander L Rusanov 《Polymer International》2011,60(8):1248-1258
This study focuses on the synthesis and characterization of new polyamides based on an aromatic asymmetric diamine‐containing phenoxy‐substituted benzophenone segment. Low‐temperature solution polycondensation reactions of this diamine with various aromatic diacid chlorides containing ether, hexafluoroisopropylidene or diphenylsilane groups resulted in polyamides with molecular weights in the range 102 900–113 200 g mol?1. The structures of these monomers and the corresponding polymers were fully confirmed using elemental analysis and infrared and NMR spectroscopy. All polyamides were easily soluble at room temperature in polar aprotic solvents and even in less polar solvents such as tetrahydrofuran. The polymers showed excellent thermal stability, up to 385 °C, and displayed glass transition temperatures in the range 225–256 °C. All the polymers presented blue florescence upon irradiation with UV light and thus show promise for applications in electroluminescent devices. Copyright © 2011 Society of Chemical Industry 相似文献
768.
Aleksandra Mielewczyk-Gryn Katarzyna Gdula-Kasica Bogusław Kusz Maria Gazda 《Ceramics International》2013,39(4):4239-4244
Magnesium doped lanthanum ortho-niobate (La0.98Mg0.02NbO4) was prepared by the molten salt synthesis method. X-ray diffraction and dilatometry methods were used to study high temperature behavior of the ceramic material. Special attention was paid to the phase transition between the monoclinic and tetragonal phases. The values of spontaneous strain on the basis of unit cell parameter, obtained by Rietveld refinement, have been calculated as well as Landau order parameter. The thermal expansion coefficient (TEC) of La0.98Mg0.02NbO4 was determined to be 12×10?6 1/K and 8×10?6 1/K below and above 500 °C, respectively. 相似文献
769.
Statistical techniques coupled with genetic algorithm (GA) were used to identify optimal values of key operational variables in fluid catalytic cracking (FCC) process. A Kellog Orthoflow F fluid catalytic cracking process model was considered. It is known as a highly nonlinear process with a large number of variables with strong interactions among them. A reduced process model was obtained through factorial design technique to be used as a process function in the optimisation work giving as result the operational conditions that maximise conversion without infringing operational restrictions with savings in computational burden and time. An increase of 8.71% in process conversion was achieved applying GA as optimisation technique. © 2012 Canadian Society for Chemical Engineering 相似文献
770.
Tiziana Armaroli Maria Bevilacqua Marcella Trombetta Aìda Gutirrez Alejandre Jorge Ramirez Guido Busca 《Applied Catalysis A: General》2001,220(1-2):181-190
The interaction of aromatic hydrocarbons benzene, toluene, o-, m- and p-xylene and of methyl pyridines (in particular 2,6-lutidine) with H-ZSM-5 and H-FER zeolites has been studied. Two different H-ZSM-5 samples with strongly different intensity ratios between the two main OH stretching bands have been used. Benzene, toluene and p-xylene enter easily the cavities and give rise to three different H-bonded complexes. Two of them are strongly bonded while the third is likely a very hindered and distorted one. o-Xylene enters slowly the cavities and m-xylene even more slowly. Faster diffusion occurs at higher temperatures. On the contrary, xylenes do not enter the FER cavities. In spite of its steric hindrance, supposed to be the same of m-xylene, 2,6-lutidine enters fast the ZSM channels and is protonated by the internal sites. On the contrary, it does not enter the FER cavities, but it is protonated too on the external silanols sites. Evidence is provided for some kind of heterogeneity of the internal sites of ZSM-5 zeolite. Additionally, it is concluded that other effects besides the molecular sieving effect may play a role in the access and diffusion of molecules into the zeolite channels. 相似文献