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81.
The U(1) gauge structure of torsion and dislocation in three dimensional Riemann-Cartan manifold have been studied. The local topological structure of dislocation have been presented by so-called topological method in which the quantum number is by Hopf indices and Brouwer degree. Furthermore, the relationship between the dislocation lines and Wilson lines of the U(1) gauge theory is discussed by using the Chern-Simons theory. 相似文献
82.
An innovative intense neutron generator of 14 MeV neutrons for the irradiation of future reactor materials is presented. Negative pions are produced inside a 5–10 T magnetic field by an intense deuteron beam interacting with a carbon target. The pions and the muons from pion decay in flight are collected in the backward direction and stopped in a deuterium-tritium-hydrogen target of high density. Using an 18 MW deuteron beam at 1.5 GeV (12 mA=7.5 × 1016d/s), circa 1016gt– /s can be generated, decaying to muons of which up to 1015 µ–/s stop in the D/T/H mixture. Assuming Xc=100 fusions per muon, the µCF source produces 14 MeV neutrons with a source strength of up to 1017 n/s, i.e. a neutron power of 200 kW. The environment of the second target, the neutron source itself, can be made to resemble part of the Tokamak ring to be simulated for irradiation test samples. 相似文献
83.
Marcello Mascini George G. Guilbault Ian R. Monk Colin Hill Michele Del Carlo Dario Compagnone 《Mikrochimica acta》2008,163(3-4):227-235
The aim of this work was to optimize, by means of molecular modeling software, biomimetic-based traps for pathogen detection suitable for analytical applications like screening or pre-analytical methods. The pathogen prototype system chosen was Listeria monocytogenes because of the large number of X ray and NMR structures available. 298 oligopeptides were computationally designed mimicking the binding pocket of the mammalian protein E-cadherin, the target of Listeria monocytogenes adhesion, internalin A. The contribution of individual peptides to bind was investigated using FRED, a protein-ligand docking program. Ten peptides were selected for experimental analysis taking as selection parameters the length, the position in the docking pocket and the score of simulated binding energy. A series of competition assays were carried out using high density colorimetric microarray using various bacteria species (Listeria monocytogenes, Listeria monocytogenes genetically modified without internalin A, Listeria innocua and Lactococcus lactis) in solution with computationally selected peptides. The data demonstrated that peptides could be able to distinguish Listeria monocytogenes with an EC50 up to 107cfu × mL?1. In particular the peptide with the best calculated binding score gave the highest statistically unambiguous response toward Listeria monocytogenes compared to other bacteria, demonstrating that rationally simulated approach can be useful as preliminary screening in the choice of biomimetic ligands. 相似文献
84.
85.
Summary Some correlations are presented of experimental data, which mainly concern the transition from normal to anomalous flow at the inlet of Pitot tubes in dilute polymer solutions.Such transition is associated with the onset of pressure defect, and reveals some aspects of statistical regularity; when the polymer solution is fresh, it happens at a given value of the ratio of flow velocity to Pitot tube diameter v/d, and it seems not dependent or only slightly dependent on the diameter value alone. But the aging of the solution enhances the importance of the diameter value, and the transition value of v/d increases in a different way for different diameters, more quickly in the case of the bigger ones.This behaviour together with the observation that the viscosity does not affect significantly the phenomenon, brings the authors to confirm that such solutions cannot be considered as a viscoelastic continuum, but as a fluid with a structure due to large associations of water molecules and macromolecules, whose linear dimension is significant with respect to the probe diameter.
Sommario Vengono presentate alcune correlazioni fra i dati sperimentali che riguardano essenzialmente la transizione da flusso normale a flusso anomalo in prossimità ed all'interno della bocca dei tubi di Pitot immersi in soluzioni diluite di polimeri.La transizione è associata alla genesi del recupero incompleto di pressione e presenta caratteri di regolarità in senso statistico; con soluzioni fresche si ha transizione mediamente attorno ad un dato valore del rapporto v/d tra la velocità del flusso ed il diametro del Pitot, in modo indipendente o scarsamente dipendente dal valore del solo diametro.Ma, invecchiando la soluzione, anche il valore del diametro in sè rivela influenza, poiché il valore relativo alla transizione del rapporto v/d cresce più rapidamente per i diametri più grandi. Questo comportamento, assieme alla constatazione che la viscosità non ha influenza rilevante sul fenomeno, conduce a confermare che queste soluzioni non possono essere ritenute un continuo visco-elastico, ma piuttosto un fluido strutturato da larghe associazioni di molecole di acqua e macromolecole, con una dimensione lineare non insignificante in confronto al diametro del Pitot.相似文献
86.
Mono and disubstituted acetylenes react with aryl iodides containing a variety of functional groups in the presence of palladium catalyst, formic acid and a tertiary amine to give trisubstituted alkenes. 相似文献
87.
88.
Giuseppe Chidichimo Marcello Longeri Giuseppina Menniti Giovanni Romeo Alida Ferlazzo 《Magnetic resonance in chemistry : MRC》1984,22(1):52-54
The ring mobility of some 1,5-benzodiazepine-2,4-diones and 1,4-benzodiazepin-2-one has been investigated by the temperature dependence of their 1H NMR spectra. The activation parameters have been obtained, and the influence of N-1 substitution on the ring mobility is discussed, taking into account previously reported data for similar compounds. 相似文献
89.
90.