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21.
Hongliang Ren Chun Jiang Weisheng Hu Mingyi Gao Jingyuan Wang 《Optics Communications》2006,266(1):342-348
A novel three-port channel add/drop filter consisting of two waveguides and two cavities is proposed. One is used for a resonant tunneling-based channel add/drop operation from the bus waveguide to the add/drop waveguide, while the other is used to realize the wavelength-selective reflection feedback in the bus waveguide. By means of coupled mode theory in time, the conditions to achieve 100% add efficiency are derived thoroughly. Based on these theoretical analysis, the channel add filter and some other multi-channel filters are designed in two-dimensional photonic crystals (2D PCs) with square lattice of dielectric rods in air. The numerical results by using the finite-difference time-domain (FDTD) method demonstrate almost complete channel add/drop tunneling at resonance via the three-port systems. 相似文献
22.
SOME CHARACTERIZATIONS OF α-BLOCH SPACES ON THE UNIT BALL OF C~n 总被引:2,自引:0,他引:2
杨微生 《数学物理学报(B辑英文版)》1997,(4)
1IntroductionLetH(B)denotetheclassofall11olomorphicfunctionsintheunitballB.WesaythatfEB",ifWhenn=1,replacethembyH(D)alldB"(D).HaxdyandLittlewoodprovedthat([3,2]):B"(D)=Lip(1--or).WeknowthatLipscanbeusedtodescribethedualspaceofHardyspaceHP(D)for0
相似文献
23.
Jean-Piere Aubin在他所著的“Applied Functional Analysis”一书中为了推理的需要,常不加证明地宣布存在具某特定性质的函数,这些函数有些是的确存在的,有些则不尽然,现各举一例。 相似文献
24.
A hyperspectral imaging system is developed and is used to identify cracks and fracture defects in solar cells. The basic principles and key technologies of this system are presented, along with a characterization of its performance. The system can provided both single-band images and spectrums of solar cells by laser scanning and hyperspectral imaging. The spectral angle mapper algorithm is used to identify cracks on the surface of solar cells. Experiment results show that this is a non-contact, no-destructive method for detecting cracks in solar cells. 相似文献
25.
Some studies on quantum dots (QD) as donors that enhance the fluorescence of a dye as an acceptor through fluorescence resonance energy transfer (FRET) have been reported. However, in the present work we discovered that CdS quantum dots sharply quenched the fluorescence of acridine orange (AO). Also, DNA enhanced the fluorescent signals of AO quenched by CdS. The extents of enhancement were in good proportion to the DNA concentrations. Based on this, a sensitive method was employed to determine DNA with both good selectivity and sensitivity. The calibration curve was linear over 60-4,000 ng mL(-1) and the determination limit (3sigma) was 4.39 ng mL(-1). 相似文献
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Multi-focus image fusion is an important method used to combine the focused parts from source multi-focus images into a single full-focus image. Currently, to address the problem of multi-focus image fusion, the key is on how to accurately detect the focus regions, especially when the source images captured by cameras produce anisotropic blur and unregistration. This paper proposes a new multi-focus image fusion method based on the multi-scale decomposition of complementary information. Firstly, this method uses two groups of large-scale and small-scale decomposition schemes that are structurally complementary, to perform two-scale double-layer singular value decomposition of the image separately and obtain low-frequency and high-frequency components. Then, the low-frequency components are fused by a rule that integrates image local energy with edge energy. The high-frequency components are fused by the parameter-adaptive pulse-coupled neural network model (PA-PCNN), and according to the feature information contained in each decomposition layer of the high-frequency components, different detailed features are selected as the external stimulus input of the PA-PCNN. Finally, according to the two-scale decomposition of the source image that is structure complementary, and the fusion of high and low frequency components, two initial decision maps with complementary information are obtained. By refining the initial decision graph, the final fusion decision map is obtained to complete the image fusion. In addition, the proposed method is compared with 10 state-of-the-art approaches to verify its effectiveness. The experimental results show that the proposed method can more accurately distinguish the focused and non-focused areas in the case of image pre-registration and unregistration, and the subjective and objective evaluation indicators are slightly better than those of the existing methods. 相似文献
29.
This paper studies the sampled-data control problem for a class of high-order nonlinear systems. Based on exact discrete-time equivalent model of the sampled-data system, a multi-rate sampled-data controller with the form of a power series expansion is designed to achieve the global asymptotic stability of the closed-loop system under some assumptions. Approximate solutions of the proposed controller are proved to be effective by a theoretical analysis. The results show that, compared with the emulated control scheme, the approximate controllers allow considering larger sampling periods and enlarge the domain of attraction for a given sampling period. Finally, a simulation example is given to show the effectiveness of the proposed control scheme. 相似文献
30.
Design of optical system in laser display has always been an important research topic. From the aspect of decreasing the system volume and improving the light efficiency, it can be found that when the size of fly's-eye lens and the value of f/# are definite, the more fly's-eye arrays there are, the more useful it will be to the decrease of the optical engine size, which means that more honeycombs on fly's-eye lens and better dodging effect can be more beneficial for the decrease of the system size. After the optimal design for the rectangular elements on sub-fly's-eye lens and then doing 4000 ray tracing, the light transmittance turns out to be good with little parasitic light and scattering light. 相似文献