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471.
We propose a mechanism where high entanglement between very distant boundary spins is generated by suddenly connecting two long Kondo spin chains. We show that this procedure provides an efficient way to route entanglement between multiple distant sites. We observe that the key features of the entanglement dynamics of the composite spin chain are well described by a simple model of two singlets, each formed by two spins. The proposed routing mechanism is a footprint of the emergence of a Kondo cloud in a Kondo system and can be engineered and observed in varied physical settings. 相似文献
472.
Ramanujan?s Master Theorem states that, under suitable conditions, the Mellin transform of a power series provides an interpolation formula for the coefficients of this series. Based on the duality of compact and noncompact reductive Riemannian symmetric spaces inside a common complexification, we prove an analogue of Ramanujan?s Master Theorem for the spherical Fourier transform of a spherical Fourier series. This extends the results proven by Bertram for Riemannian symmetric spaces of rank-one. 相似文献
473.
Astolfi A Bottalico P Barbato G 《The Journal of the Acoustical Society of America》2012,131(1):247-257
This work concerns speech intelligibility tests and measurements in three primary schools in Italy, one of which was conducted before and after an acoustical treatment. Speech intelligibility scores (IS) with different reverberation times (RT) and types of noise were obtained using diagnostic rhyme tests on 983 pupils from grades 2-5 (nominally 7-10 year olds), and these scores were then correlated with the Speech Transmission Index (STI). The grade 2 pupils understood fewer words in the lower STI range than the pupils in the higher grades, whereas an IS of ~97% was achieved by all the grades with a STI of 0.9. In the presence of traffic noise, which resulted the most interfering noise, a decrease in RT from 1.6 to 0.4 s determined an IS increase on equal A-weighted speech-to-noise level difference, S/N(A), which varied from 13% to 6%, over the S/N(A) range of -15 to +6 dB, respectively. In the case of babble noise, whose source was located in the middle of the classroom, the same decrease in reverberation time leads to a negligible variation in IS over a similar S/N(A) range. 相似文献
474.
AT Toci P Crupi G Gambacorta T Dipalmo D Antonacci A Coletta 《Journal of mass spectrometry : JMS》2012,47(9):1104-1112
Negroamaro is an autochthonous wine grape variety of Southern Italy, which is becoming very important for the Italian wine market. The wine aroma is primary affected by the chemical composition of grapes, which can be influenced also by agronomic practices such as soil management. In this study, the free and bound aroma characterization was performed by gas chromatography-mass spectrometry analyses, and the influence of two soil managements (cover cropping and soil tillage) was evaluated. A total of 40 volatile compounds were observed in the wine samples. Alcohols (55.7?mg/L), fatty acids (7.0?mg/L) and esters (6.6?mg/L) were found as the main classes in Negroamaro wine. The results showed that the aroma composition of Negroamaro wine was positively affected by soil tillage probably because of the higher water stress (ψ(s) ) recorded in the vines from this treatment. Indeed, among the free volatile compounds, higher contents of esters, carboxylic acids, alcohols, phenolics and acetamides together with lower contents of sulfurs compounds were found in soil tillage wine. Conversely, no difference was observed in glycoside volatile compounds. Copyright ? 2012 John Wiley & Sons, Ltd. 相似文献
475.
Zhou M Pasquale FL Dowben PA Boosalis A Schubert M Darakchieva V Yakimova R Kong L Kelber JA 《J Phys Condens Matter》2012,24(7):072201
Direct growth of graphene on Co(3)O(4)(111) at 1000 K was achieved by molecular beam epitaxy from a graphite source. Auger spectroscopy shows a characteristic sp(2) carbon lineshape, at average carbon coverages from 0.4 to 3 ML. Low energy electron diffraction (LEED) indicates (111) ordering of the sp(2) carbon film with a lattice constant of 2.5(±0.1) ? characteristic of graphene. Sixfold symmetry of the graphene diffraction spots is observed at 0.4, 1 and 3 ML. The LEED data also indicate an average domain size of ~1800 ?, and show an incommensurate interface with the Co(3)O(4)(111) substrate, where the latter exhibits a lattice constant of 2.8(±0.1) ?. Core level photoemission shows a characteristically asymmetric C(1s) feature, with the expected π to π* satellite feature, but with a binding energy for the 3 ML film of 284.9(±0.1) eV, indicative of substantial graphene-to-oxide charge transfer. Spectroscopic ellipsometry data demonstrate broad similarity with graphene samples physically transferred to SiO(2) or grown on SiC substrates, but with the π to π* absorption blue-shifted, consistent with charge transfer to the substrate. The ability to grow graphene directly on magnetically and electrically polarizable substrates opens new opportunities for industrial scale development of charge- and spin-based devices. 相似文献
476.
477.
Guido Barone Pasquale Cacace Giuseppina Castronuovo Vittorio Elia 《Journal of solution chemistry》1984,13(9):625-635
The heats of dilution in water of methyl--D-galacto-, gluco-, and xylopyranosides and the heats of mixing with the respective -isomers were determined calorimetrically at 25°C. The excess enthalpies, expressed as virial expansions as a function of the molalities, lead to the evaluation of the self- and cross-interaction coefficients. As for other saccharide derivatives, the pairwise interaction coefficients are positive and larger than those for the parent monosacharides. The cross coefficients, in turn, are smaller than the homogeneous coefficients resulting in a favorable contribution to the free energy of mixing. This indicates the existence of a weak, water-mediated, but still stereospecific recognition between pairs of solute molecules. 相似文献
478.
Lorenzo Farina Alfredo Germani Gabriella Mavelli Pasquale Palumbo 《Journal of Mathematical Modelling and Algorithms》2010,9(3):233-245
The modern systems biology approach to the study of molecular cellular biology, consists in the development of computational
tools to support the formulation of new hypotheses on the molecular mechanisms underlying the observed cell behavior. Recent
biotechnologies are able to provide precise measures of gene expression time courses in response to a large variety of internal
and environmental perturbations. In this paper, we propose a simple algorithm for the selection of the “best” regulatory network
motif among a number of alternatives, using the expression time course of the genes which are the final targets of the activated
signalling pathway. To this aim, we considered the Hill nonlinear ODEs model to simulate the behavior of two ubiquitous motifs:
the single input motif and the multi output feed-forward loop motif. Our algorithm has been tested on simulated noisy data assuming the presence of a step-wise regulatory signal. The results
clearly show that our method is potentially able to robustly discriminate between alternative motifs, thus providing a useful
in silico identification tool for the experimenter. 相似文献
479.
Vito Fiandanese Daniela Bottalico Giuseppe Marchese Angela Punzi 《Tetrahedron》2004,60(50):11421-11425
A new stereoselective methodology for the synthesis of both dihydroxerulin and xerulin has been devised. The key step required cross-coupling reactions between the bromo trienyne, (1E,3E,5E)-1-bromo-8-trimethylsilyl-1,3,5-octatrien-7-yne and the appropriate conjugated diynes. The palladium-catalyzed tandem cross-coupling/cyclization reaction of the resulting polyenynes with (Z)-3-iodo-2-propenoic acid led directly to dihydroxerulin or xerulin with a high degree of stereoselectivity. 相似文献
480.
A simple, accurate and reproducible analytical method is described for the extraction and the simultaneous determination of 18 amino acids in different for geographical origin Spirulina alga samples using phenylisothiocianate as derivatizating agent in natural feed. The best experimental hydrolysis conditions have been studied varying the temperature, the time and the hydrolyzing reagent. The separation and the quantitative analysis of the by-products have been carried out by HPLC analysis and UV detection. An amino acid pattern is compared with that proposed by the Food Agriculture Organization (FAO) for an ideal protein and with those of some traditional feed. 相似文献