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51.
The present work describes the design of three flat superlens structures for acoustic source imaging and explores an active acoustic metamaterial (AAM) to realise such a design. The first two lenses are constructed via the coordinate transform method (CTM), and their constituent materials are anisotropic. The third lens consists of a material that has both a negative density and a negative bulk modulus. In these lenses, the quality of the images is “clear” and sharp; thus, the diffraction limit of classical lenses is overcome. Finally, a multi-control strategy is developed to achieve the desired parameters and to eliminate coupling effects in the AAM. 相似文献
52.
《European Journal of Operational Research》2002,139(3):533-542
We consider a satellite following orbits around the earth in order to take shots corresponding to images requested by various customers. The daily operations of such a satellite consist of defining a feasible and satisfactory shot sequence. This problem involves both combinatorial and multiple criteria difficulties. Indeed, the number of feasible shot sequences grows significantly with the number of images asked for, and the evaluation of a shot sequence is based on several conflicting criteria. We propose to formulate this problem as the selection of a multiple criteria path in a graph without circuit. Our approach for solving this problem involves two stages: generation of efficient paths and selection of a satisfactory path using a multiple criteria interactive procedure. 相似文献
53.
DAI Hong-Yi ZHANG Ming KUANG Le-Man 《理论物理通讯》2008,50(7):73-76
We present a scheme for probabilistic remote preparation of multi-qubit with three-party from a sender to either of two receivers. The quantum channel is composed of a partial entangled tripartite GHZ state. We obtain the successful totM probability of the scheme in the general case and special case, respectively. We also calculate total classical communication cost required in the RSP process with three-party in the general case and special case, respectively. 相似文献
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Fluid Dynamics - To predict the boundary layer transition on swept wings, experimental and numerical researches were conducted to obtained the accurate boundary layer transition front and to... 相似文献
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Highly fluorescent LaPO4:Ce/Tb@LaPO4@SiO2 (core/shell/Si) nanorods(NRs) were fabricated with an average length 100 nm by co-precipitation process at low temperature. X-ray diffraction (XRD), Transmission electron microscopy (TEM), energy dispersive X-ray analysis, Fourier transform infrared, optical absorption and photoluminescence spectral techniques were applied to investigate the crystal structure, phase purity, morphology, surface chemistry and optical properties of the as-prepared samples. XRD results confirmed the formation of highly crystalline with single phase, monoclinic type structure. TEM image illustrates the poly-dispersed, narrow size distributed, irregular size rod-shaped nanostructures, with mean diameters of 20 nm and average lengths up to 140 nm. FTIR spectral analysis confirmed the silica surface modification. The comparative emission spectral study shows highest luminescence intensity of core/shell NRs, due to a reduction in nonradiative transition rate. The emission intensity enhancement proves that growing of an inert LaPO4 layer on the surface of luminescent core-NRs was an effective way to suppress surface related quenching mechanism. These well crystalline, highly aqueous soluble along with extraordinary colloidal stability core/shell/Si NRs were extremely suitable material in fluorescent bio-labeling applications. 相似文献
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Lin Zhou Lei Huang Nathalie Bouet Konstantine Kaznatcheev Matthew Vescovi Yifan Dai Shengyi Li Mourad Idir 《Journal of synchrotron radiation》2016,23(5):1087-1090
Surface slope profile is widely used in the metrology of grazing‐incidence reflective optics instead of surface height profile. Nevertheless, the theoretical and experimental model currently used in deterministic optical figuring processes is based on surface height, not on surface slope. This means that the raw slope profile data from metrology need to be converted to height profile to perform the current height‐based figuring processes. The inevitable measurement noise in the raw slope data will introduce significant cumulative error in the resultant height profiles. As a consequence, this conversion will degrade the determinism of the figuring processes, and will have an impact on the ultimate surface figuring results. To overcome this problem, an innovative figuring model is proposed, which directly uses the raw slope profile data instead of the usual height data as input for the deterministic process. In this paper, first the influence of the measurement noise on the resultant height profile is analyzed, and then a new model is presented; finally a demonstration experiment is carried out using a one‐dimensional ion beam figuring process to demonstrate the validity of our approach. 相似文献