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81.
In this paper we consider the global existence of weak solutions to a class of Quantum Hydrodynamics (QHD) systems with initial data, arbitrarily large in the energy norm. These type of models, initially proposed by Madelung [44], have been extensively used in Physics to investigate Superfluidity and Superconductivity phenomena [19,38] and more recently in the modeling of semiconductor devices [20] . Our approach is based on various tools, namely the wave functions polar decomposition, the construction of approximate solution via a fractional steps method which iterates a Schrödinger Madelung picture with a suitable wave function updating mechanism. Therefore several a priori bounds of energy, dispersive and local smoothing type, allow us to prove the compactness of the approximating sequences. No uniqueness result is provided. 相似文献
82.
Neukirch H Guido E Liantonio R Metrangolo P Pilati T Resnati G 《Chemical communications (Cambridge, England)》2005,(12):1534-1536
The halogen bonding driven self-assembly of 1,8-diiodoperfluorooctane and N,N,N',N'-tetramethyl-p-phenylenediamine induces the formation of a chiral and enantiopure co-crystal wherein the fluorinated chains adopt an unusual gauche arrangement. 相似文献
83.
Silvana Modena Pierangelo Calini Guglielmo Gregorio Giovanni Moggi 《Journal of fluorine chemistry》1988,40(2-3):349-357
Liquid phase fluorination of diethyleneglycol dimethyl ether tetraethyleneglycol dimethyl ether, 2[1,2-dichloro-1,2-difluoroethyl] tetrahydrofuran and 2[1,2-dichloro-1,2-difluoroethyl] dioxane 1,4 produce the corresponding perfluoroethers in 56, 43, 67 and 74 % yields respectively.
The by-products are partially fluorinated compounds and no fragmentation is observed.
The simplicity of the reactions and method of preparation make this approach to fluorinated fluids and oils industrially attractive. 相似文献
84.
Dicarboxylic Acid Separation by Dynamic and Size‐Matched Recognition in Solution and in the Solid State
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Dr. Vijith Kumar Dr. Tullio Pilati Prof. Dr. Giancarlo Terraneo Dr. Gianluca Ciancaleoni Prof. Dr. Alceo Macchioni Prof. Dr. Giuseppe Resnati Prof. Dr. Pierangelo Metrangolo 《Angewandte Chemie (International ed. in English)》2018,57(5):1327-1331
Bis(trimethylammonium) alkane diiodides dynamically encapsulate dicarboxylic acids through intermolecular hydrogen bonds between the I? anions of the hosts and the carboxylic OH groups of the guests. A selective recognition is realized when the size of the I????HOOC(CH2/CF2)nCOOH???I? superanion matches the dication alkyl chain length. Dynamic recognition is also demonstrated in solution, where the presence of the size‐matching organic salt boosts the acid solubility profile, thus allowing efficient mixture separation. 相似文献
85.
Mele A Metrangolo P Neukirch H Pilati T Resnati G 《Journal of the American Chemical Society》2005,127(43):14972-14973
A new heteroditopic receptor for alkali metal halides has been designed and synthesized. It is comprised of a well-established motif for cation binding and a motif for halogen-bonding-based anion recognition processes. The single-crystal X-ray structure of the complex between the heteroditopic receptor and sodium iodide is reported. Thanks to the cooperativity of metal coordination and the strong I-...I halogen bonding, the ion pair is fully separated. The boosting effect of the binding of the anion through halogen bonding on the coordination of the cation by the receptor has been proved also in solution by NMR experiments. The selectivity of the new heterotopic receptor toward different alkali metal halides has been tested by ESI mass experiments. 相似文献
86.
Metrangolo P Meyer F Pilati T Proserpio DM Resnati G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(20):5765-5772
Halogen bonding (XB) has been used to assemble tetrakis(4-pyridyl)pentaerythritol (tetradentate XB acceptor) with different alpha,omega-diiodoperfluoroalkanes (bidentate XB donors) or tetrakis(4-iodotetrafluorophenyl)pentaerythritol (tetradentate XB donor). The remarkable linearity of the XB formed, the rodlike character of alpha,omega-diiodoperfluoroalkanes and the mutual complementarities of pentaerythritol partners, translate the three-dimensional character of the XB acceptor into open primary networks, which interpenetrate to avoid the presence of voids and to ensure segregation of the modules. Two-dimensional (2D) square 4(4) layers (sql) with fourfold and fivefold interpenetration, as well as an eightfold diamondoid network (dia) of class Ia and a remarkable tenfold dia network of class IIIa, have been obtained. 相似文献
87.
Dr. Maria I. Martinez Espinoza Dr. Lorenzo Sori Dr. Andrea Pizzi Prof. Dr. Giancarlo Terraneo Ivana Moggio Eduardo Arias Dr. Gianluca Pozzi Dr. Simonetta Orlandi Dr. Valentina Dichiarante Prof. Dr. Pierangelo Metrangolo Dr. Marco Cavazzini Prof. Dr. Francesca Baldelli Bombelli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(38):9078-9087
A small series of boron-dipyrromethene (BODIPY) dyes, characterized by the presence of multibranched fluorinated residues, were designed and synthesized. The dyes differ in both the position (para-perfluoroalkoxy-substituted phenyl ring or boron functionalization) and number of magnetically equivalent fluorine atoms (27 or 54 fluorine atoms per molecule). Photophysical and crystallographic characterization of the synthesized BODIPYs was carried out to evaluate the effect of the presence of highly fluorinated moieties on the optical and morphological properties of such compounds. 相似文献
88.
Intermolecular interactions and the role of fluorine substitution have been investigated for a halogenated-ethane anesthetic. 2-Bromo-2-chloro-1,1,1-trifluoroethane, BrClCHCF3 (Halothane), has been in situ pressure frozen in a diamond anvil cell and its structure determined by single-crystal X-ray diffraction at 1.85(5) GPa/296 K. Crystal is triclinic, space group . In this racemic structure the enantiomorphic molecules are substitutionally disordered at the same general positions in that way that bromine and chlorine atoms occupy the same site at the 50:50 ratio. Despite the fact that only the Br and Cl atoms are disordered, the crystal packing is dominated by halogen?halogen and halogen?hydrogen interactions. This X-ray diffraction study provides structural explanation of considerably increased vapor pressure of Halothane compared to its hydrogenated analogue. 相似文献
89.
90.
Pierangelo Chiappa 《Fiber and Integrated Optics》2013,32(4):278-285
Abstract Bandwidth-hungry services, such as higher speed Internet, voice over IP (VoIP), and IPTV, allow people to exchange and store huge amounts of data among worldwide locations. In the age of global communications, domestic users, companies, and organizations around the world generate new contents making bandwidth needs grow exponentially, along with the need for new services. These bandwidth and connectivity demands represent a concern for operators who require innovative technologies to be ready for scaling. To respond efficiently to these demands, Alcatel-Lucent is fast moving toward photonic integration circuits technologies as the key to address best performances at the lowest “bit per second” cost. This article describes Alcatel-Lucent's contribution in strategic directions or achievements, as well as possible new developments. 相似文献