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131.
We numerically demonstrate that properly designed plasmonic covers can be used to enhance the performance of near-field scanning optical microscopy (NSOM) systems based on the employment of apertureless metallic tip probes. The covering material, exhibiting a near-zero value of the real permittivity at the working frequency, is designed in such a way to dramatically reduce the undesired scattering due to the strongly plasmonic behavior of the tip. Though the light scattering by the tip end is necessary for the correct operation of NSOMs, the additional scattering due to the whole probe affects the signal-to-noise ratio and thus the resolution of the acquired image. By covering the whole probe but not the very tip, we show that unwanted scattering can be effectively reduced. A realistic setup, working at mid-IR frequencies and employing silicon carbide covers, has been designed and simulated to confirm the effectiveness of the proposed approach. 相似文献
132.
Luca Scorrano Filiberto Bilotti Ekmel Ozbay Lucio Vegni 《Applied Physics A: Materials Science & Processing》2011,103(3):927-931
In this paper, a novel approach, based on the employment of frequency selective surfaces, to enhance the power transmission
through sub-wavelength apertures at the microwave frequencies is presented. A heuristic interpretation of the phenomenon is
given, as well as an analytical model, based on the transmission line network representation. Finally, the performance of
the proposed structure is validated through a set of full-wave numerical simulations. 相似文献
133.
Deoxyfunicone, rapicone and their 5,6-epoxy-derivatives are γ-pyrone compounds with cytostatic and antiproliferative properties. Here we describe a synthesis of these compounds by carbonylative Stille coupling between kojic acid derivatives and functionalized iodo aryl compounds. The main advantages of this patent pending synthetic strategy lie in the simplicity and clean conversion of products, and in the possibility to obtain a high number of analogs by minor changes of the synthetic synthons. 相似文献
134.
Before marketing external gear pumps are subjected to a running in process to increase their efficiency. However, this is
one of the most time-consuming tasks of the entire manufacturing process. Therefore, a mathematical model for optimizing the
running in process can be a useful tool for time-to-market reduction. In particular, in this paper a model for the analysis
of the dynamic behaviour of external gear pumps, developed by the authors in previous works, is modified and used for simulating
the running in process. The modified model is presented and validated via experimental data. A good correlation between simulation
and test results guarantees the effectiveness of the model in determining the amount and the distribution of the removed material
during the running in process. A meaningful reduction (16%) of the global running in time has been achieved with the introduction
of a modified running in process drawn from simulation results. 相似文献
135.
The nature of a metal-insulator transition tuned by external gates in quantum Hall systems with point constrictions, as reported in recent experiments [S. Roddaro, Phys. Rev. Lett. 95, 156804 (2005)10.1103/PhysRevLett.95.156804], is examined. We attribute this phenomenon to a splitting of the integer edge into conducting and insulating stripes, the latter wide enough to allow for the stability of the edge structure. Interchannel impurity scattering and interchannel Coulomb interactions do not destabilize this picture. 相似文献
136.
Images-based suppression of unwanted global signals in resting-state functional connectivity studies
Federico Giove Tommaso Gili Vittorio Iacovella Emiliano Macaluso Bruno Maraviglia 《Magnetic resonance imaging》2009
Correlated fluctuations of low-frequency fMRI signal have been suggested to reflect functional connectivity among the involved regions. However, large-scale correlations are especially prone to spurious global modulations induced by coherent physiological noise. Cardiac and respiratory rhythms are the most offending component, and a tailored preprocessing is needed in order to reduce their impact. Several approaches have been proposed in the literature, generally based on the use of physiological recordings acquired during the functional scans, or on the extraction of the relevant information directly from the images. In this paper, the performances of the denoising approach based on general linear fitting of global signals of noninterest extracted from the functional scans were assessed. Results suggested that this approach is sufficiently accurate for the preprocessing of functional connectivity data. 相似文献
137.
[structure: see text] Two novel antimitotic heterocyclic alkaloids, ceratamines A (1) and B (2), have been isolated from the marine sponge Pseudoceratina sp., collected in Papua New Guinea. The structures of 1 and 2 were elucidated by analysis of spectroscopic data. 相似文献
138.
Emiliano Principi Andrea Di Cicco Agnieszka Witkowska Roberto Marassi 《Journal of synchrotron radiation》2007,14(3):276-281
A commercial fuel cell has been successfully modified to carry out X‐ray absorption spectroscopy (XAS) measurements under optimized in operando conditions. The design is conceived for the performance of XAS experiments in transmission mode over a wide range of X‐ray energies above 6 keV, owing to the reduced absorption of the cell. The wide angular aperture allows the collection of XAS in fluorescence mode and of X‐ray diffraction patterns when needed. Details of the design of the cell and its performances are given. The quality of the extended X‐ray absorption fine‐structure spectra under working conditions has been verified at the ESRF and ELETTRA synchrotron radiation facilities, showing that relatively fast and low‐noise transmission measurements on electrodes over a wide range of catalyst concentrations and energies are feasible. 相似文献
139.
Barbato Michele Grappe Roland Lacroix Mathieu Lancini Emiliano 《Mathematical Programming》2023,197(1):307-336
Mathematical Programming - Given a graph $$G=(V,E)$$ and an integer $$k\ge 1$$ , the graph $$H=(V,F)$$ , where F is a family of elements (with repetitions allowed) of E, is a k-edge-connected... 相似文献
140.
We present the first experimental demonstration, to the best of our knowledge, of ghost imaging realized with intense beams generated by a parametric downconversion interaction seeded with pseudothermal light. As expected, the real image of the object is reconstructed satisfying the thin-lens equation. We show that the experimental visibility of the reconstructed image is in accordance with the theoretically expected one. 相似文献