844 research outputs found

    Surface Potential Decay and DC Conductivity of TiO2-based Polyimide Nanocomposite Films

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    Polymer nanocomposites have attracted wide interest as a method of enhancing polymer properties and extending their applications. Surface potential decay has been used widely as a tool to monitor charge transport and trapping characteristics of insulating materials. Polyimide (PI) as an engineering material has been paid more attention due to high thermal and chemical stability, good mechanical property and excellent insulating property in a wide range of temperature. There has been a lot of work over last few years on optical, thermal and mechanical properties of polyimide nanocomposites. However, little attention has been given to the effect of nano-fillers on charge transport and trapping in polyimide nanocomposites. In the present paper, pure, 1%, 3%, 5% and 7% polyimide nanocomposites was examined by using surface potential decay in conjunction with dc conductivity measurement and both experiments showed that 3% is the optimal value for electrical insulation

    Novel Approaches for Regional Multifocus Image Fusion

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    Image fusion is a research topic about combining information from multiple images into one fused image. Although a large number of methods have been proposed, many challenges remain in obtaining clearer resulting images with higher quality. This chapter addresses the multifocus image fusion problem about extending the depth of field by fusing several images of the same scene with different focuses. Existing research in multifocus image fusion tends to emphasis on the pixel-level image fusion using transform domain methods. The region-level image fusion methods, especially the ones using new coding techniques, are still limited. In this chapter, we provide an overview of regional multi-focus image fusion, and two different orthogonal matching pursuit-based sparse representation methods are adopted for regional multi-focus image fusion. Experiment results show that the regional image fusion using sparse representation can achieve a comparable even better performance for multifocus image fusion problems

    Amygdalin suppresses the proliferation, migration and EMT of gastric cancer cells by inhibiting TGF-β/Smad signal pathway

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    Purpose: To investigate the effects of amygdalin on the proliferation, motility and epithelial mesenchymal transformation (EMT) of gastric cancer cells and to elucidate the operating mechanisms of action.Methods: Gastric cancer AGS cells were treated with amygdalin (2.5, 5 and 10 mg/L). MTT and colony formation assays were used to investigate the effect of amygdalin on gastric cancer cell proliferation, while wound healing and Transwell assays were also carried out to determine its effect on the motility of gastric cancer cells. Immunoblot assays were used to investigate the effects of amygdalin on epithelial mesenchymal transformation (EMT) process and TGF-β/Smad pathway in gastric cancer cells.Results: Treatment with amygdalin suppressed the proliferation of gastric cancer AGS cells (p < 0.05). Amygdalin suppressed the migration and invasion of AGS cells in vitro (p < 0.05). Additionally, amygdalin suppressed epithelial mesenchymal transformation (EMT) in AGS cells, and suppressed TGF-β/Smad pathway (p < 0.05), thereby suppressing growth, motility, and EMT in AGS cells.Conclusion: Amygdalin may be useful for the treatment of gastric cancer; however, further studies are required ascertain this

    Progressively Dual Prior Guided Few-shot Semantic Segmentation

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    Few-shot semantic segmentation task aims at performing segmentation in query images with a few annotated support samples. Currently, few-shot segmentation methods mainly focus on leveraging foreground information without fully utilizing the rich background information, which could result in wrong activation of foreground-like background regions with the inadaptability to dramatic scene changes of support-query image pairs. Meanwhile, the lack of detail mining mechanism could cause coarse parsing results without some semantic components or edge areas since prototypes have limited ability to cope with large object appearance variance. To tackle these problems, we propose a progressively dual prior guided few-shot semantic segmentation network. Specifically, a dual prior mask generation (DPMG) module is firstly designed to suppress the wrong activation in foreground-background comparison manner by regarding background as assisted refinement information. With dual prior masks refining the location of foreground area, we further propose a progressive semantic detail enrichment (PSDE) module which forces the parsing model to capture the hidden semantic details by iteratively erasing the high-confidence foreground region and activating details in the rest region with a hierarchical structure. The collaboration of DPMG and PSDE formulates a novel few-shot segmentation network that can be learned in an end-to-end manner. Comprehensive experiments on PASCAL-5i and MS COCO powerfully demonstrate that our proposed algorithm achieves the great performance

    Compact and high-performance vortex mode sorter for multi-dimensional multiplexed fiber communication systems

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    With the amplitude, time, wavelength/frequency, phase, and polarization/spin parameter dimensions of the light wave/photon almost fully utilized in both classical and quantum photonic information systems, orbital angular momentum (OAM) carried by optical vortex modes is regarded as a new modal parameter dimension for further boosting the capacity and performance of the systems. To exploit the OAM mode space for such systems, stringent performance requirements on a pair of OAM mode multiplexer and demultiplexer (also known as mode sorters) must be met. In this work, we implement a newly discovered optical spiral transformation to achieve a low-cross-Talk, wide-opticalbandwidth, polarization-insensitive, compact, and robust OAM mode sorter that realizes the desired bidirectional conversion between seven co-Axial OAM modes carried by a ring-core fiber and seven linearly displaced Gaussian-like modes in parallel single-mode fiber channels. We further apply the device to successfully demonstrate high-spectralefficiency and high-capacity data transmission in a 50-km OAM fiber communication link for the first time, in which a multi-dimensional multiplexing scheme multiplexes eight orbital-spin vortex mode channels with each mode channel simultaneously carrying 10 wavelength-division multiplexing channels, demonstrating the promising potential of both the OAM mode sorter and the multi-dimensional multiplexed OAM fiber systems enabled by the device. Our results pave the way for futureOAM-based multi-dimensional communication systems
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