The electron mobility of 4,7-diphyenyl-1,10-phenanthroline (BPhen) at various thicknesses (50-300 nm) has been estimated by using space-charge-limited current measurements. The measured bulk mobility is in excellent a...
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ZnO nanofibers were prepared by sol-gel processing and electrospinning technique. Poly (vinyl acetate) (PVA) and zinc acetate were used as precursors of PVA/ zinc acetate composite fibers. The composite and calcined n...
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The vortex formation and entrainment characteristics for a round transverse jet in shallow water were experimentally investigated by means of a combination of LIF flow visualization and PIV measurement. A scarf vortex...
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The vortex formation and entrainment characteristics for a round transverse jet in shallow water were experimentally investigated by means of a combination of LIF flow visualization and PIV measurement. A scarf vortex wrapped around the main body of the jet is formed in the near-wall region due to the interaction between the resulting wall jet and sufficiently shallow crossflow, with some more or less unsteady flow properties and with spreading ranges as functions of both the velocity ratio and the water depth within the near field. The entrainment of the ambient crossflow fluid into the jet main body is closely associated with the time-evolving features of the shear layer between the jet and surrounding fluid as well as the induced vortical structures near the wall. In the case of slight impingement upon the wall, the interaction between the jet shear layer and the weak, unstable scarf vortex gives rise to an appreciable local entrainment enhancement, confined in the near-wall region in the vicinity of the stagnation point. While in the case of intense impingement upon the wall, the well-organized and stable scarf vortex gives rise to a greatly enhanced entrainment and a greatly increased lateral spreading rate nearly throughout the overall near field as compared to the conventional wall jet. In addition, the entrainment of the ambient crossflow fluid by the scarf vortex in this case occurs largely on the surface of the unique spiral roller structure by itself due to the presence of smaller and unorganized eddies, and accordingly the scarf vortex is likely to keep its spiral roller structure steadily to a relatively great downstream distance within the near field.
@@In recent years, organic light-emitting diodes (OLEDs) for the application of flat panel displays (FPDs) have been attracting many researchers. Blue OLEDs are the potential light source to make full color FPDs by co...
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@@In recent years, organic light-emitting diodes (OLEDs) for the application of flat panel displays (FPDs) have been attracting many researchers. Blue OLEDs are the potential light source to make full color FPDs by color conversion method. However, due to a large energy bandgap of blue emission materials, blue OLEDs were widely reported to have relatively low luminance efficiencies and high operation voltage, compared to the devices with low energy emission wavelength.
Surface electromyography(sEMG)is used to detect and analyze human muscle ***,flexible noninvasive electrodes(FNEs)have emerged to extract bioelectrical signals from individual *** FNEs to be deployed as a central comp...
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Surface electromyography(sEMG)is used to detect and analyze human muscle ***,flexible noninvasive electrodes(FNEs)have emerged to extract bioelectrical signals from individual *** FNEs to be deployed as a central component of physiological signal acquisition,the quest for elevated signal-to-noise ratio and density is compelling owing to the small amplitude of ***,we review recent progress in FNEs for sEMG *** summarize the needed properties of FNEs,compare the differences between passive electrodes and active electrodes and exemplify applications of *** also conclude the current challenges and future opportunities in sEMG acquisition.
A novel approach of visual attention based video object segmentation in MPEG compressed domain is proposed in this paper. DCT coefficients and motion vectors (MVs) are firstly parsed from compressed streams. Analysis ...
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ISBN:
(纸本)9780863418365
A novel approach of visual attention based video object segmentation in MPEG compressed domain is proposed in this paper. DCT coefficients and motion vectors (MVs) are firstly parsed from compressed streams. Analysis of the scene texture is then proposed to decide the best appropriate information for region growing. MVs are exploited to perform region growing if texture is complex, otherwise DC coefficients and MVs are used together to perform region growing. Meanwhile, MVs of I frames are calculated by backward projection of MVs of subsequent P frames, then global motion compensation is performed using the MVs of I frames to obtain local MVs. Subsequently statistical region growing is exploited to segment the image into homogeneous regions. Finally an improved attention model is proposed to extract visual attention objects, which is based on position, clearness and local MVs. The attention model makes the segmentation results more accordant with human's perception. The experimental results conducted on standard test sequences demonstrate the efficient, real-time, robust performance of the proposed approach.
A novel algorithm is developed to detect moving objects and remove cast shadows by exploiting textural and spatial-temporal features. Multi-scale wavelet transformation is used to segment moving objects based on spati...
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