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991.
Luciana Sartore Maurizio Penco Fabio Bignotti Isabella Peroni Maria Helena Gil M. Andrade Ramos Alberto D'Amore 《应用聚合物科学杂志》2002,85(6):1287-1296
A new process was developed which enables one to obtain surface‐modified silica with a high heavy metal ion complexing ability. The synthetic approach is based on grafting of vinyl‐terminated macromonomers onto silica via covalent bonding. A proper selection of the macromonomer structure, molecular weight, and molecular weight distribution allows materials to be obtained with a range of desirable properties. The process has been tested on various dispersions (ranging from 35 and 200 μm) of silica particles and two structurally related macromonomers. Native silica and the resulting mixed organic–inorganic products were fully characterized by IR spectroscopy, SEM, yield of grafting (elemental analysis and calcination), density (helium pycnometry), specific surface area (BET method), and pore size (gas adsorption and mercury porosimetry) measurements. It was found that the corresponding polymers are effectively grafted onto the surface; the density, surface area, and pore size of the silica particles decrease with polymer grafting. Preliminary results on metal‐ion uptake indicate that polymer‐grafted silica exhibits an excellent complexing ability. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1287–1296, 2002 相似文献
992.
Alberto Ubaldini Vincenzo Buscaglia Claudio Uliana Giorgio Costa Maurizio Ferretti 《Journal of the American Ceramic Society》2003,86(1):19-25
The formation of BaZrO3 from very fine (70–90 nm) ZrO2 powders and coarser (∼1 μm) BaCO3 powders has been studied in dry and humid air up to 1300°C using TGA/DTA, XRD, SEM, TEM, and EDS microanalysis. In the temperature range 900°–1100°C, barium is rapidly transported at the surface of the ZrO2 particles and reacts, forming BaZrO3 . The compound grows as a concentric layer with gradual consumption of the central ZrO2 particle. The overall formation kinetics of BaZrO3 is well described by a diminishing core model, and the most likely rate-determining step is a phase-boundary process at the ZrO2 –BaZrO3 moving interface. The size and shape of the final particles is generally determined by the morphology of the starting ZrO2 particles and not by that of the BaCO3 . The reaction is faster in humid air than in dry air, and the activation energy decreases from 294 kJ·mol−1 (dry air) to 220 kJ·mol−1 (humid air). When the fraction reacted is >80–90 mol%, the reaction rate rapidly decreases. 相似文献
993.
Danila Di Majo Marco Giammanco Maurizio La Guardia Elisa Tripoli Santo Giammanco Enrico Finotti 《Food research international (Ottawa, Ont.)》2005,38(10):1161-1166
Epidemiological surveys have shown an inverse relationship between the intake of fruit and the incidence of coronary heart disease and some type of cancer. Data found in the literature regarding the flavonoids in general while this study focuses on flavanones, a subclass of flavonoids which occurs in Citrus fruit. The aim of this work is to elucidate the antioxidant or pro-oxidant behaviours of some common flavanones and to determine their activity–structure relationships as antioxidant using the crocin bleaching inhibition assay. The compounds studied were regarding both the aglycon form and the glycoside form. Data evidence that the substitution of the 7th OH group of the flavanones by a neohesperidoside influences the relationship between structure and antioxidant activity. In fact, the 3′,4′-catechol structure and the O-methylation, in the aglycone forms, do not result significant. On the other hands, in the glycosylate forms, the 3′,4′-catechol structure noticeably increases the antioxidant power and the O-methylation decreases the antioxidant activity. The influence of the O-glycosylation with a rutinose molecule is neglectable. 相似文献
994.
本工作采用TH3SL程序对水堆事故后安全壳内的气体分布及蒸汽冷凝进行了随机模拟。校验计算表明 :此程序的模拟结果是可信的 相似文献
995.
Maurizio Toselli Joseph A Gardella Massimo Messori Adam M Hawkridge Francesco Pilati Claudio Tonelli 《Polymer International》2003,52(8):1262-1274
The air‐side surface composition of a series of poly(ε‐caprolactone)–perfluoropolyether–poly(ε‐caprolactone) triblock copolymers with different compositions and block lengths have been studied by angle‐dependent X‐ray photoelectron spectroscopy (XPS). The weight percentage of the perfluoropolyether (PFPE) and polycaprolactone (PCL) blocks, and ethylene oxide linker (RH) has been calculated in different ways: from C1s, O1s and F1s photoemission peaks and by line fitting of the C1s and O1s envelopes. The atomic sensitivity factors and the parameters used to fit the peak envelopes have been experimentally determined using some reference materials. A critical discussion of the different methods used in the surface characterization and the degradation of PFPE segments, induced by irradiation beam, have been also reported. A large excess of PFPE with respect to the bulk composition was observed in all samples, and the angular dependence of the XPS signal demonstrated that the content of the fluorinated block segment increased by decreasing the sampling depth. The PFPE surface concentration was also decreased by increasing the PCL/PFPE ratio, but the surfaces of the samples were still dominated by PFPE segments for copolymers with a bulk PFPE composition lower than 10%. Moreover, copolymers with similar PCL/PFPE bulk ratios but with different PFPE block lengths, showed similar PFPE surface composition when the number‐average molecular weight (Mn) was 2000 and 3200 g mol?1, while that observed for copolymers containing PFPE block with Mn 900 g mol?1 was lower. Copyright © 2003 Society of Chemical Industry 相似文献
996.
Maurizio Di Bonito Monica Cantile Francesca Collina Rossella De Cecio Teresa Petrosino Gerardo Botti 《International journal of molecular sciences》2014,15(8):13166-13171
Granular cell tumor (GCT) is a benign tumor of the breast that can mimic, on breast imaging, invasive carcinomas. Biological evolution of mammary GCT is unknown, especially if it is associated with an invasive carcinoma in the same or contralateral breast. This report details the morphological features of these synchronous lesions highlighting their biological characteristics and suggesting an appropriate follow up. 相似文献
997.
Using a tubular heat exchanger to improve the conditioning process of the olive paste: Evaluation of yield and olive oil quality
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998.
Adrian L. Kerrihard Kornél Nagy Brian D. Craft Maurizio Beggio Ronald B. Pegg 《Journal of the American Oil Chemists' Society》2015,92(8):1153-1163
Although fatty acid (FA) composition is known to be of fundamental importance to oxidative stability in lipids, consistent quantifications of the magnitude of this association have proved elusive. The objective of this study was to quantify the relationship between FA composition and stability on a large scale within comparable lipid systems, with the numerical effects of individual outcome factors (e.g. output of a singular assay, oxidative products after a brief period of time, etc.) attenuated by incorporation into a comprehensive summation of stability. The stability of 50 plant‐based oils and fats was modeled according to FA composition, utilizing a quantification of stability that encompassed the complete oxidation curves of four distinct classical assays (two 1° and two 2° oxidation assessments) throughout 2 months of accelerated storage (60 °C). In our models, the concentrations of monounsaturated FA (MUFA), diunsaturated FA (DiUFA), and triunsaturated FA (TriUFA) together demonstrated a very strong correlation with our consolidated measure of stability (r2 = 0.915; greater than observed with our assessments by individual assays). The resultant model also indicated the relative effect upon magnitude of oxidation of MUFA:DiUFA:TriUFA to be approximately 1:3:12—substantially greater than the 1:2:3 ratio of their relative unsaturation. 相似文献
999.
Paolo Mancinelli Davide Fabiani Andrea Saccani Maurizio Toselli Michel F. Fréchette 《应用聚合物科学杂志》2015,132(18)
This article deals with the investigation of electrical properties of epoxy‐based nanocomposites containing graphene oxide nanofillers dispersed in the polymer matrix through two‐phase extraction. Broadband dielectric spectroscopy and dc electrical conductivity as a function of electric field have been evaluated in specimens containing up to 0.5 wt % of nanofiller. Nanocomposites containing pristine graphene oxide do not show significant changes of electrical properties. On the contrary, the same materials after a proper thermal treatment at 135°C, able to provoke the in situ reduction of graphene oxide, exhibit higher permittivity and electrical conductivity, without showing large decrease of breakdown voltage. Moreover, a nonlinear behavior of the electrical conductivity is observed in the range of electric fields investigated, i.e. 2–30 kV mm?1. A new relaxation phenomenon with a very low temperature dependence is also evidenced at high frequency in reduced graphene oxide composites, likely associated to induced polarization of electrically conductive nanoparticles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41923. 相似文献
1000.
Li JIA Zhi FANG Maurizio GUADAGNINI Kypros PILAKOUTAS Zhengmeng HUANG 《Frontiers of Structural and Civil Engineering》2021,15(6):1426
The ultra-high-performance concrete (UHPC) and fiber-reinforced polymer (FRP) are well-accepted high-performance materials in the field of civil engineering. The combination of these advanced materials could contribute to improvement of structural performance and corrosion resistance. Unfortunately, only limited studies are available for shear behavior of UHPC beams reinforced with FRP bars, and few suggestions exist for prediction methods for shear capacity. This paper presents an experimental investigation on the shear behavior of UHPC beams reinforced with glass FRP (GFRP) and prestressed with external carbon FRP (CFRP) tendons. The failure mode of all specimens with various shear span to depth ratios from 1.7 to 4.5 was diagonal tension failure. The shear span to depth ratio had a significant influence on the shear capacity, and the effective prestressing stress affected the crack propagation. The experimental results were then applied to evaluate the equations given in different codes/recommendations for FRP-reinforced concrete structures or UHPC structures. The comparison results indicate that NF P 18-710 and JSCE CES82 could appropriately estimate shear capacity of the slender specimens with a shear span to depth ratio of 4.5. Further, a new shear design equation was proposed to take into account the effect of the shear span to depth ratio and the steel fiber content on shear capacity. 相似文献