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341.
F. Ambrosino A. Antonelli M. Antonelli F. Archilli P. Beltrame G. Bencivenni C. Bini C. Bloise S. Bocchetta F. Bossi P. Branchini G. Capon D. Capriotti T. Capussela F. Ceradini P. Ciambrone E. De Lucia A. De Santis P. De Simone G. De Zorzi A. Denig A. Di Domenico C. Di Donato B. Di Micco M. Dreucci G. Felici S. Fiore P. Franzini C. Gatti P. Gauzzi S. Giovannella E. Graziani M. Jacewicz V. Kulikov G. Lanfranchi J. Lee-Franzini M. Martini P. Massarotti S. Meola S. Miscetti M. Moulson S. Müller F. Murtas M. Napolitano F. Nguyen M. Palutan A. Passeri V. Patera P. Santangelo B. Sciascia A. Sibidanov T. Spadaro L. Tortora P. Valente G. Venanzoni R. Versaci 《The European Physical Journal C - Particles and Fields》2010,65(3-4):703-703
342.
Federico De Martino Giancarlo Valente Aline W. de Borst Fabrizio Esposito Alard Roebroeck Rainer Goebel Elia Formisano 《Magnetic resonance imaging》2010
The combination of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has been proposed as a tool to study brain dynamics with both high temporal and high spatial resolution. Multimodal imaging techniques rely on the assumption of a common neuronal source for the different recorded signals. In order to maximally exploit the combination of these techniques, one needs to understand the coupling (i.e., the relation) between electroencephalographic (EEG) and fMRI blood oxygen level-dependent (BOLD) signals. 相似文献
343.
A transparent glass with the composition 60B2O3–30Li2O–10Nb2O5 (mol%) was prepared by the melt quenching technique. The glass was heat-treated with and without the application of an external electric field. The as-prepared sample was heat-treated (HT) at 450, 500 and 550 °C and thermoelectric treated (TET) at 500 °C. The following electric fields were used: 50 kV/m and 100 kV/m. Differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, dc and ac conductivity, as a function of temperature, were used to investigate the glass and glass-ceramics properties. LiNbO3 crystals were detected, by XRD, in the 500 °C HT, 550 °C HT and 500 °C TET samples. The presence of an external electric field, during the heat-treatment process, improves the formation of LiNbO3 nanocrystals at lower temperatures. However, in the 550 °C HT and in the TET samples, Li2B4O7 was also detected. The value of the σdc decreases with the rise of the applied field, during the heat-treatment. This behavior can indicate an increase in the fraction of the LiNbO3 crystallites present in these glass samples. The dc and ac conduction processes show dependence on the number of the ions inserted in the glass as network modifiers.The Raman analysis suggests that the niobium ions are, probably, inserted in the glass matrix as network formers.These results reflect the decisive effect of temperature and electric field applied during the thermoelectric treatment in the structure and electric properties of glass-ceramics. 相似文献
344.
The ferroelectric material potassium niobate (KNbO3) has a large number of exceptional electronic and optical properties with important technological applications. Due to the high preparation difficulties and costs of the single crystals, a considerable interest in the preparation of glass-ceramics with the KNbO3 crystal phase exists. In this work we present the preparation of a glass, with the composition 40B2O3–40K2O–20Nb2O5 (% mole), through the melt-quenching method and glass-ceramics obtained by controlled heat-treatments. The samples structure was analyzed using X-ray power diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. KNbO3 crystals were detected in the glass sample treated at 500 °C. For treatments at temperatures above 500 °C, other niobium-based crystal phases are present. The behavior of the heat-treatment temperature parameter, in the glass and glass ceramic structure, is discussed. 相似文献
345.
Julie Meimoun Yupin Phuphuak Remi Miyamachi Yong Miao Marc Bria Cyril Rousseau Guilherme Nogueira Andreia Valente Audrey Favrelle-Huret Philippe Zinck 《Molecules (Basel, Switzerland)》2022,27(3)
Cyclodextrins (CDs) are cyclic oligosaccharides used in many fields. Grafting polymers onto CDs enables new structures and applications to be obtained. Polylactide (PLA) is a biobased, biocompatible aliphatic polyester that can be grafted onto CDs by -OH-initiated ring-opening polymerization. Using 4-dimethylaminopyridine (DMAP) as an organocatalyst, a quantitative functionalization is reached on native α-, β-, γ- and 2,3-dimethyl- β-cyclodextrins. Narrow molecular weight distributions are obtained with the native CDs (dispersity < 1.1). The DMAP/β-CD combination is used as a case study, and the formation of an inclusion complex (1/1) is shown for the first time in the literature, which is fully characterized by NMR. The inclusion of DMAP into the cavity occurs via the secondary rim of the β-CD and the association constant (Ka) is estimated to be 88.2 M−1. Its use as an initiator for ring-opening polymerization leads to a partial functionalization efficiency, and thus a more hydrophilic β-CD-PLA conjugate than that obtained starting from native β-CD. Polymerization results including also the use of the adamantane/β-CD inclusion complex as an initiator suggest that inclusion of the DMAP catalyst into the CD may not occur during polymerization reactions. Rac-lactide does not form an inclusion complex with β-CD. 相似文献