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71.
Paola Di Giacomo Stefano Orlando Marco Dell’Ariccia Bruno Brandimarte 《Applied Physics A: Materials Science & Processing》2013,110(1):71-75
We theoretically show that a polarization-independent optical band-stop filter operation can be performed by a two-dimensional sub-wavelength array of symmetric cross-shaped plasmonic nanoantennas. The proposed filter’s optical properties can be controlled by varying the size and periodicity of the plasmonic nanoantennas. So, this can be used to design filters in many frequency ranges of interest. In addition, the filter is simply constructed as a coating with only 30-nm thickness, which is much thinner than the operation wavelength, and thus facilitates the fabrication and further large-scale optical integration. 相似文献
72.
Mauro Dell’Amico Manuel Iori Silvano Martello Michele Monaci 《Journal of Heuristics》2012,18(6):939-942
A recent paper (Davidovi? et al., J. Heuristics, 18:549?C569, 2012) presented a bee colony metaheuristic for scheduling independent tasks to identical processors, evaluating its performance on a benchmark set of instances from the literature. We examine two exact algorithms from the literature, the former published in 1995, the latter in 2008 (and not cited by the authors). We show that both such algorithms solve to proven optimality all the considered instances in a computing time that is several orders of magnitude smaller than the time taken by the new algorithm to produce an approximate solution. 相似文献
73.
Caterina Ciminelli Francesco Dell’Olio Vittorio M. N. Passaro Mario N. Armenise 《Optical and Quantum Electronics》2009,41(4):285-298
Scattering loss in high-index-contrast optical waveguides has been modeled by a rigorous 3D numerical algorithm based on volume
current method. The electromagnetic field generated by the wire current distribution simulating sidewalls roughness has been
calculated by 3D finite element method. The developed modeling technique does not introduce any approximation in radiated
power estimation. Numerical results obtained by our model have been compared with some experimental results reported in literature
for four typical sub-micrometer high-index-contrast waveguides realized by different technologies and a very good agreement
(relative error less than 3%) has been demonstrated. Closed-form expressions for scattering loss in low-index-contrast waveguides
have been also derived and discussed. Developed modeling technique has been compared with other three-dimensional algorithms
for scattering loss estimation and its advantages in terms of accuracy, computation time and generality have been pointed
out. Scattering loss dependence on the parameters of the roughness distribution has been finally discussed. 相似文献
74.
Cortellessa Gino Arpino Fausto Dell’Isola Marco Ficco Giorgio Iacomini Luigi Fernicola Vito Bertiglia Fabio 《Journal of Thermal Analysis and Calorimetry》2019,138(4):2901-2912
Journal of Thermal Analysis and Calorimetry - The 2010/31/CE directive has highlighted the necessity to improve the energy efficiency in buildings, since they are responsible for 40% of energy... 相似文献
75.
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77.
H. -D. Dell J. Fiedler und R. Teichgräber 《Fresenius' Journal of Analytical Chemistry》1970,249(1):41-44
Zusammenfassung DC-Charakteristica einiger Psychopharmaka (Chlorprothixen, Prothixen, Clopenthixol, Meprotixol, Amitriptylin und Nortriptylin), deren Metaboliten und Derivate in 6 verschiedenen azeotropen Laufmittelsystemen werden beschrieben und die Fluorescenzmaxima dieser Verbindungen in 60%iger Schwefelsäure angegeben. Am Beispiel des Chlorprothixens und Chlorprothixensulfoxids wird die gemeinsame sowie separate Isolierung und quantitative Bestimmung von Wirkstoffen aus biologischem Material gezeigt. Fluorimetrische Unterschiede bei Clopenthixol und Flupentixol gegenüber deren Metaboliten ermöglichen die Bestimmung der Wirksubstanzen im Gemisch.
Thin-layer chromatography and fluorimetric characteristics of some psychotherapeutics of the thioxanthene and dibenzo(a,d)-1,4-cycloheptadiene series
TLC characteristics are described of some psychopharmacological agents (Chlorprothixen, Prothixen, Clopenthixol, Flupentixol, Meprotixol, Amitriptylin und Nortriptylin) and of their metabolites and derivatives in six different developing solvent systems as well as the fluorescence maxima of these compounds in 60% sulphuric acid.By way of the examples of Chlorprothixen and Chlorprothixen sulphoxide the isolation of reactive agents from biological material and their determination are shown.The determination of Clopenthixol and Flupentixol in mixtures with their corresponding metabolites is possible due to differences in their fluometric spectra.相似文献
78.
Mixtures of a polar solute 4-n-pentyl-4'-cyanobiphenyl in a non-polar nematic solvent exhibit two separated low frequency dielectric relaxations for concentrations of the solute between 2 mol% and 20 mol% over a limited temperature range. This behaviour is attributed to coexisting nematic and smectic B phases, in which the polar solute probe has different relaxation frequencies. The observed dielectric spectra can be accurately fitted to two Debye-like relaxations, and the strengths of the absorptions are proportional to the amounts of the coexisting phases. A microscopic determination of the phase diagram confirms the assignment of the coexisting phases, and it is concluded that there is a preference of the dipolar probe molecule for the smectic B phase, which is induced as a result of solute-solvent interactions. 相似文献
79.
Jrgen Holm Kristensen Ian Farnan 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2002,158(1-2)
An efficient theoretical formalism and advanced experimental methods are presented for studying the effects of anisotropic molecular motion and relaxation on solid-state central transition NMR spectra of half-integer quadrupole nuclei. The theoretical formalism is based on density operator algebra and involves the stochastic Liouville–von Neumann equation. In this approach the nuclear spin interactions are represented by the Hamiltonian while the motion is described by a discrete stochastic operator. The nuclear spin interactions fluctuate randomly in the presence of molecular motion. These fluctuations may stimulate the relaxation of the system and are represented by a discrete relaxation operator. This is derived from second-order perturbation theory and involves the spectral densities of the system. Although the relaxation operator is valid only for small time intervals it may be used recursively to obtain the density operator at any time. The spectral densities are allowed to be explicitly time dependent making the approach valid for all motional regimes. The formalism has been applied to simulate partially relaxed central transition 17O NMR spectra of representative model systems. The results have revealed that partially relaxed central transition lineshapes are defined not only by the nuclear spin interactions but also by anisotropic motion and relaxation. This has formed the basis for the development of central transition spin-echo and inversion-recovery NMR experiments for investigating molecular motion in solids. As an example we have acquired central transition spin-echo and inversion-recovery 17O NMR spectra of polycrystalline cristobalite (SiO2) at temperatures both below and above the α–β phase transition. It is found that the oxygen atoms exhibit slow motion in α-cristobalite. This motion has no significant effects on the fully relaxed lineshapes but may be monitored by studying the partially relaxed spectra. The α–β phase transition is characterized by structural and motional changes involving a slight increase in the Si–O–Si bond angle and a substantial increase in the mobility of the oxygen atoms. The increase in the Si–O–Si angle is supported by the results of 17O and 29Si NMR spectroscopy. The oxygen motion is shown to be orders of magnitude faster in β-cristobalite resulting in much faster relaxation and characteristic lineshapes. The measured oscillation frequencies are consistent with the rigid unit mode model. This shows that solid-state NMR and lattice dynamics simulations agree and may be used in combination to provide more detailed models of solid materials. 相似文献
80.
H. -D. Dell und J. Fiedler 《Fresenius' Journal of Analytical Chemistry》1977,284(2):126-127
Ohne ZusammenfassungHerrn Prof. Dr. H. J. Bielig zum 65. Geburtstag gewidmet. 相似文献