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91.
This review focuses on the optical properties and device applications of deterministic aperiodic media generated by mathematical rules with spectral features that interpolate in a tunable fashion between periodic crystals and disordered random media. These structures are called Deterministic Aperiodic Nano Structures (DANS) and can be implemented in different materials (linear and nonlinear) and physical systems as diverse as dielectric multilayers, optical gratings, photonic waveguides and nanoparticle arrays. Among their distinctive optical properties are the formation of multi‐fractal bandgaps and characteristic optical resonances, called critical modes, with unusual localization, scaling and transport properties. The goal of the paper is to provide a detailed review of the conceptual foundation and the physical mechanisms governing the complex optical response of DANS in relation to the engineering of novel devices and functionalities. The discussion will mostly focus on passive and active planar structures with enhanced light‐matter coupling for photonics and plasmonics technologies. 相似文献
92.
93.
C. Dal Savio K. Pierz G. Ade H.-U. Danzebrink E.O. Göbel A. Hangleiter 《Applied physics. B, Lasers and optics》2006,84(1-2):317-322
Single self-assembled InAs quantum dots embedded in a In0.12Ga0.88As quantum well and emitting in the near infrared have been optically investigated. The dependence on the excitation power
of the single quantum dot photoluminescence has been used to identify the emission of the biexciton complex. The biexciton
binding energy, which has been measured for a dozen dots, increases with increasing exciton transition energy for the dot
sizes investigated in the present work, as a consequence of stronger confinement in a smaller quantum dot. The obtained data
is compared with experimental results available in the literature for InAs quantum dots.
PACS 78.67.Hc; 73.21.La; 78.55.Cr 相似文献
94.
Five cellulase components were identified and purified in one step from Streptomyces strain A20 using electroendosmotic preparative electrophoresis. By this procedure up to 18 mg of protein mixture could be loaded on the column, with an estimated recovery of 60-70% of total activity; activity and protein recovery could be estimated 32% and 47% respectively, if only activity peaks were considered. In comparison to other purification methods, this technique results in high protein recovery and resolution of applied samples. 相似文献
95.
96.
F. Frontera D. Dal Fiume T. Franceschini G. Landini E. Morelli M. Pamini A. Rubini S. Silvestri G. Spada E. Costa D. Cardini A. Emanuele 《Il Nuovo Cimento C》1984,7(6):656-672
Summary We describe a balloon experiment, currently in the marking, devoted to the observation of celestial X-ray sources. The main
features of the X-ray telescope are summarized as follows. It operates in the energy band from 20 to 300 keV. Its energy resolution
is about 17% at 60 keV. Under the hypothesis of 104 s of observing time, 3 mbar of residual atmospheric pressure and 3σ of statistical significance, the expected sensitivity
of the instrument is 2·10−6 photons/cm2 s keV in the (20÷200) keV energy band, corresponding to about 1 milliCrab. Its high sensitivity allows us to detect both
time variability in the flux and cyclotron lines in the spectra of X-ray sources. It has a field of view of 3° FWHM and has
the possibility of resolving complex fields by using multipitch modulation collimators. With such a configuration its angular
resolution is about 10′.
Paper presented at the 2° Convegno Nazionale di Fisica Cosmica, held at L'Aquila, 29 May–2 June 1984. 相似文献
97.
98.
C. Dal Cappello J. Langlois M. C. Dal Cappello B. Joulakian A. Lahmam-Bennani A. Duguet R. Tweed 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,23(4):389-396
Electron-impact double ionization of noble gases is investigated theoretically for the case of high incident energies (5 keV). An ab initio calculation is made including partial correlation in the initial state as well as in the final state. The results of the calculations are compared with those of other theories and with the first available (e, 3e) experimental data on krypton 4p 6. 相似文献
99.
Jack A. A. Van der Veen René van Dal 《The Journal of the Operational Research Society》1991,42(11):971-980
The no-wait flow-shop scheduling problem (NWFSSP) with a makespan objective function is considered. As is well known, this problem is ????-hard for three or more machines. Therefore, it is interesting to consider special cases, i.e. special structured processing time matrices, that allow polynomial time solution algorithms. Furthermore, it is well known that the NWFSSP with a makespan objective function can be formulated as a travelling salesman problem (TSP). It is observed that special structured processing time matrices for the NWFSSP lead to special structured distance matrices for which the TSP is polynomially solvable. Using this observation, it is shown that some NWFSSPs with fixed processing times on all except two machines are well solvable while the others are conjectured to be ????-hard. Also, it is shown that NWFSSPs with a mean completion time objective function restricted to semi-ordered processing time matrices are easily solvable. 相似文献
100.
If Au = - div(a(x, Du)) is a monotone operator defined on the Sobolev space W1,P(R
n, 1 < p < + , with a(x,0) = 0 for a.e. x Rn, the capacity C_A(E,F) relative to A can be defined for every pair (E,F) of bounded sets in Rn with E F. The main properties of the set function CA(E,F) are investigated. In particular it is proved that CA(E,F) is increasing and countably subadditive with respect to E, decreasing with respect to F, and continuous, in a suitable sense, with respect to E and F. 相似文献