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61.
Iacus Stefano Maria Santamaria Carlos Sermi Francesco Spyratos Spyros Tarchi Dario Vespe Michele 《Nonlinear dynamics》2020,101(3):1901-1919
Nonlinear Dynamics - Countries in Europe took different mobility containment measures to curb the spread of COVID-19. The European Commission asked mobile network operators to share on a... 相似文献
62.
Dario Tamascelli 《Entropy (Basel, Switzerland)》2020,22(11)
The chain mapping of structured environments is a most powerful tool for the simulation of open quantum system dynamics. Once the environmental bosonic or fermionic degrees of freedom are unitarily rearranged into a one dimensional structure, the full power of Density Matrix Renormalization Group (DMRG) can be exploited. Beside resulting in efficient and numerically exact simulations of open quantum systems dynamics, chain mapping provides an unique perspective on the environment: the interaction between the system and the environment creates perturbations that travel along the one dimensional environment at a finite speed, thus providing a natural notion of light-, or causal-, cone. In this work we investigate the transport of excitations in a chain-mapped bosonic environment. In particular, we explore the relation between the environmental spectral density shape, parameters and temperature, and the dynamics of excitations along the corresponding linear chains of quantum harmonic oscillators. Our analysis unveils fundamental features of the environment evolution, such as localization, percolation and the onset of stationary currents. 相似文献
63.
Natalia Calonghi Carla Boga Patrizia Nitti Dario Telese Silvia Bordoni Giovanna Farruggia Fioretta Asaro Martina Grandi Chiara Zalambani Gabriele Micheletti 《Molecules (Basel, Switzerland)》2022,27(8)
A series of regioisomers of the hydroxystearic acid (HSA) was prepared, and the effect of the position of the hydroxyl group along the chain on a panel of human cancer cell lines was investigated. Among the various regioisomers, those carrying the hydroxyl at positions 5, 7, and 9 had growth inhibitor activity against various human tumor cell lines, including CaCo-2, HT29, HeLa, MCF7, PC3, and NLF cells. 10-HSA and 11-HSA showed a very weak effect. 8-HSA did not show inhibitory activity in all cell lines. The biological role of 7-HSA and 9-HSA is widely recognized, while little is known about the effects of 5-HSA. Therefore, the biological effects of 5-HSA in HeLa, HT29, MCF7, and NLF cell lines were investigated using the Livecyte’s ptychography technology, which allows correlating changes in proliferation, motility, and morphology as a function of treatment at the same time. 5-HSA not only reduces cell proliferation but also induces changes in cell displacement, directionality, and speed. It is important to characterize the biological effects of 5-HSA, this molecule being an important component of fatty acyl esters of hydroxy fatty acids (FAHFA), a class of endogenous mammalian lipids with noticeable anti-diabetic and anti-inflammatory effects. 相似文献
64.
Renato S. Gonnelli Mauro Tortello Dario Daghero Giovanni Alberto Ummarino Valeri A. Stepanov Jun S. Kim 《Central European Journal of Physics》2009,7(2):251-256
Point-contact Andreev-reflection (PCAR) experiments were performed in the Fe-1111 layered superconductor LaFeAsO0.9F0.1 with resistive T
c
on
∼ 27 K. The observation of two pairs of peaks in the low-temperature Andreev-reflection spectra clearly indicates the presence
of two order parameters. The behavior of the two gaps as a function of temperature, obtained by fitting the conductance curves
by means of the generalized two-band Blonder-Tinkham-Klapwijk model, shows some anomalies. A theoretical analysis performed
within the two-band Eliashberg theory with a generic electron-boson coupling can reproduce the low-temperature value of the
two gaps but generally fails in giving a satisfactory fit of their overall temperature dependence, indicating the rich and
complex physics of these newly discovered superconductors.
相似文献
65.
66.
An efficient semiclassical approach is developed and used to calculate the coherent-control map and time dependent decoherence measure for the excited-state proton transfer dynamics associated with the keto-enolic tautomerization reaction of 2-(2'-hydroxyphenyl)-oxazole. The method extends the usual bichromatic coherent-control scenario to simulate control at finite times after photoexcitation of the system. Extensive coherent control is demonstrated in a large molecule despite the ultrafast decoherence phenomena, providing results of broad theoretical and experimental interest. 相似文献
67.
Batista CD 《Physical review letters》2002,89(16):166403
I show that a spontaneous electric polarization exists in the solution of the Falicov-Kimball model by mapping the strong coupling limit of this Hamiltonian into an xxz spin 1/2 model with a magnetic field. In this way, I determine the phase diagram of the strongly interacting model and show the existence of a transition to a mixed-valence regime containing two phases: an orbitally ordered state and a Bose-Einstein condensation of excitons with a built-in electric polarization. 相似文献
68.
Dario Del Mazza Manfred G. Reinecke William B. Smith 《Magnetic resonance in chemistry : MRC》1980,14(6):540-542
Diphenyliodonium-2-carboxylate, phenyl 4-methylphenyliodonium-2-carboxylate and phenyl 5-methyl-phenyliodonium-2-carboxylate have been examined by 1H and 13C NMR spectroscopy. Each compound showed one proton considerably upfield from the others. From the two substituted compounds this was deduced to be H-6 on the ring containing the carboxylate group. Shift reagents and relaxation measurements were used to make the 13C chemical shift assignments. These data are most consistent with a cyclic, neutral structure for these iodonium carboxylates. The iodine is in the center of a trigonal bipyramid with the unsubstituted phenyl and carboxylate group apical, which places the C-6 proton in the shielding region of the adjacent phenyl group. 相似文献
69.
Grazioli C Alfè D Krishnakumar SR Sen Gupta S Veronese M Turchini S Bonini N Dal Corso A Sarma DD Baroni S Carbone C 《Physical review letters》2005,95(11):117201
The occurrence of a noncollinear magnetic structure at a Mn monolayer grown epitaxially on Fe(100) is predicted theoretically, using spinor density-functional theory, and observed experimentally, using x-ray magnetic circular dichroism (XMCD) and linear dichroism (XMLD) spectroscopies. The combined use of XMCD and XMLD at the Mn-absorption edge allows us to assess the existence of ferromagnetic and antiferromagnetic order at the interface, and also to determine the moment orientations with element specificity. The experimental results thus obtained are in excellent agreement with the magnetic structure determined theoretically. 相似文献
70.
We obtain pulse-driven Rabi oscillations guided by a generalization of the rotating-wave approximation to include, in the optical-Bloch equations, two-level systems with a time-varying transition energy. We achieve this by using chirped pulses with the central frequency given by the time-varying transition energy. Using this approach, we predict Rabi oscillations in intersubband transitions in a two-subband n-type modulation-doped quantum well by taking into account the time-dependent intersubband energy-gap renormalization due to depolarization-shift effects. We obtain Rabi oscillations for jpi (j=0,1,2, ) pulses in the presence of dephasing. 相似文献