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61.
Tunable photonic bandgap in a one-dimensional superconducting-dielectric superlattice 总被引:1,自引:0,他引:1
The transmittance of one-dimensional photonic crystals consisting of superconductor and lossless dielectric has been systematically studied through the transfer-matrix method. Obviously, the shift of the photonic bandgap (PBG) becomes more noticeable by adjusting the thicknesses of the dielectric layers than that of superconductor layers. Furthermore, the number of PBGs can be controlled by varying the thicknesses of dielectric layers. Compared to the thicknesses of the dielectric layers, the width of the PBGs is more sensitive to the thicknesses of the superconductor layers. However, the width of the first PBG promptly varies when the thicknesses of the dielectric layers increase from 0 to 40?nm. If the contribution of the normal conducting electrons of the superconductor is nonnegligible, the temperature of the superconductor has no influence on the width of the PBGs. Moreover, the damp coefficient does not affect the PBGs under low-temperature conditions. 相似文献
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A comparison of above- and in-water spectral measurements in coastal (but predominantly Case-1) conditions has shown that the uncertainty in above-water determinations of water-leaving radiances made from an offshore tower depends on the proximity of the above-water measurement with respect to the side of the platform. For purposes of this study the proximity of the sampling platform is parameterized as the perpendicular distance (denoted x) from the side of the sampling platform to the center of the area on the sea surface observed by the sea-viewing sensor, the so-called surface spot, which is set by the field of view of the radiometer (or the overlapping fields of view of a multiaperture sensor). Two above-water data processing methods were used to create a diagnostic variable (formulated for Case-1 waters only but also applicable to Case-2 conditions over short time scales) to quantify the presence of superstructure reflections. Based on the height of the tower, H, the analyses were partitioned into near- and far-field data sets (x < H and x > H, respectively). The primary conclusions of the radiometric intercomparisons are as follows: (a) the maximum perturbations occur very close to the tower ( x/H < 1), and, as x/H increases and approaches 1 (i.e., as the surface spot becomes as far away as the platform is high), the platform perturbations converge toward smaller and smaller values, and (b) within the far field (x > H) the platform perturbation is negligible, and a remote sensing 5% absolute accuracy objective can be satisfied. 相似文献
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Kim C Park JB Jee HG Lee SB Boo JH Kim SK Yoo JB Lee JS Lee H 《Journal of nanoscience and nanotechnology》2005,5(2):306-312
We report a new method to produce ordered arrays of metal nanostructures on substrates. The method employs a through-hole nanoporous alumina membrane as a mask that is attached onto the substrate, silicon in this study. The material of deposition, Au in this study, was provided by pulsed laser ablation of a target gold. At an early stage of the deposition, a significant portion of Au penetrated the alumina through-holes and formed an ordered nanodot array on the silicon surface. At the later stage, the through-hole deposition was blocked by the growth of Au film on the top surface of the alumina, so that the heights of the Au nanodots were limited to about 10 nm under current experimental conditions. Subsequent attempts to clean up the top surface of the alumina with a lower power laser illumination resulted in the formation of new nanostructures around the alumina pores, nanospheres, or nanorings, depending on the fluence of the laser and the duration of the cleanup. We will discuss the underlying mechanism of the formation of these nanostructures. 相似文献
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The mechanical response of single-walled and multiwalled carbon nanotubes to a series of external Ar atom impacts is examined with classical molecular dynamics simulations. The extent to which the carbon nanotubes deform in the direction perpendicular to their axis is found to depend on the amount of momentum transferred during the collisions. The details of the mechanical response and recovery of the nanotubes after release are also found to depend on the nanotube configurations. 相似文献
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In chronic experiment in rats pro for show, what of food biologically active "Rekitsen-RD", promotes increase of efficiency of mechanisms of detoxication, antioxidant activity and immune protection of an organism. 相似文献