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81.
We give a complete characterization, including a Lévy–Itô decomposition, of Poincaré-invariant Markov processes on
, the relativistic phase space in 1+1 spacetime dimensions. Then, by means of such processes, we construct Poincaré-invariant Gaussian random fields, and we prove a no-go theorem for the random fields corresponding to Brownian motions on
. 相似文献
82.
Alessandro Ciattoni Carlo Rizza Andrea Marini Andrea Di Falco Daniele Faccio Michael Scalora 《Laser \u0026amp; Photonics Reviews》2016,10(3):517-525
In recent years, unconventional metamaterial properties have triggered a revolution of electromagnetic research which has unveiled novel scenarios of wave‐matter interaction. A very small dielectric permittivity is a leading example of such unusual features, since it produces an exotic static‐like regime where the electromagnetic field is spatially slowly‐varying over a physically large region. The so‐called epsilon‐near‐zero metamaterials thus offer an ideal platform where to manipulate the inner details of the “stretched” field. Here we theoretically prove that a standard nonlinearity is able to operate such a manipulation to the point that even a thin slab produces a dramatic nonlinear pulse transformation, if the dielectric permittivity is very small within the field bandwidth. The predicted non‐resonant releasing of full nonlinear coupling produced by the epsilon‐near‐zero condition does not resort to any field enhancement mechanism and opens novel routes to exploiting matter nonlinearity for steering the radiation by means of ultra‐compact structures.
83.
Vajda S Lupulescu C Merli A Budzyn F Wöste L Hartmann M Pittner J Bonacić-Koutecký V 《Physical review letters》2002,89(21):213404
We present two-color fs pump-probe spectra of Na2F which were recorded by employing excitation wavelengths around 1208 nm (pump) and ionization wavelengths around 405 nm (probe). The observed oscillatory structure of the signal with a period of 185 fs shows an excellent agreement with our simulated spectra. The employed ab initio Wigner distribution approach provides clear evidence that this observation is caused by photoinduced metal bond breaking followed by a butterfly-type periodic geometric rearrangement. 相似文献
84.
Sikharulidze I Dolbnya IP Fera A Madsen A Ostrovskii BI de Jeu WH 《Physical review letters》2002,88(11):115503
The dynamics of the layer-displacement fluctuations in smectic membranes have been studied by x-ray photon correlation spectroscopy (XPCS). We report transitions from an oscillatory damping regime to simple exponential decay of the fluctuations, both as a function of membrane thickness and upon changing from specular to off-specular scattering. This behavior is in agreement with recent theories. Employing avalanche photodiode detectors and the uniform filling mode of the synchrotron storage ring, the fast limits of XPCS have been explored down to 50 ns. 相似文献
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Harald Hagendorfer Christiane Lorenz Ralf Kaegi Brian Sinnet Robert Gehrig Natalie V. Goetz Martin Scheringer Christian Ludwig Andrea Ulrich 《Journal of nanoparticle research》2010,12(7):2481-2494
This study describes methods developed for reliable quantification of size- and element-specific release of engineered nanoparticles
(ENP) from consumer spray products. A modified glove box setup was designed to allow controlled spray experiments in a particle-minimized
environment. Time dependence of the particle size distribution in a size range of 10–500 nm and ENP release rates were studied
using a scanning mobility particle sizer (SMPS). In parallel, the aerosol was transferred to a size-calibrated electrostatic
TEM sampler. The deposited particles were investigated using electron microscopy techniques in combination with image processing
software. This approach enables the chemical and morphological characterization as well as quantification of released nanoparticles
from a spray product. The differentiation of solid ENP from the released nano-sized droplets was achieved by applying a thermo-desorbing
unit. After optimization, the setup was applied to investigate different spray situations using both pump and gas propellant
spray dispensers for a commercially available water-based nano-silver spray. The pump spray situation showed no measurable
nanoparticle release, whereas in the case of the gas spray, a significant release was observed. From the results it can be
assumed that the homogeneously distributed ENP from the original dispersion grow in size and change morphology during and
after the spray process but still exist as nanometer particles of size <100 nm. Furthermore, it seems that the release of
ENP correlates with the generated aerosol droplet size distribution produced by the spray vessel type used. This is the first
study presenting results concerning the release of ENP from spray products. 相似文献
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