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Zinc Oxide-Enhanced Piezoelectret Polypropylene Microfiber for Mechanical Energy Harvesting
Zhu, Jianxiong,Zhu, Yali,Song, Weixing,Wang, Hui,Gao, Min,Cho, Minkyu,Park, Inkyu American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.23
<P>This paper reports zinc oxide (ZnO)-coated piezoelectret polypropylene (PP) microfibers with a structure of two opposite arc-shaped braces for enhanced mechanical energy harvesting. The ZnO film was coated onto PP microfibers via magnetron sputtering to form a ZnO/PP compound structure. Triboelectric Nanogenerator (TENG) based on ZnO/PP microfiber compound film was carefully designed with two opposite arc-shaped braces. The results of this study demonstrated that the mechanical energy collection efficiency of TENG based on piezoelectret PP microfiber was greatly enhanced by the coated ZnO and high-voltage corona charging method. We found that, with the step-increased distance of traveling for the movable carbon black electrode, an electrical power with an approximately quadratic function of distance was generated by this mechanical-electrical energy conversion, because more PP microfibers were connected to the electrode. Further, with a full contact condition, the peak of the generated voltage, current, and charges based on the ZnO/PP microfibers by this mechanical-electrical energy conversion with 1 m/s<SUP>2</SUP> reached 120 V, 3 μA, and 49 nC, respectively. Moreover, a finger-tapping test was used to demonstrate that the ZnO/PP microfiber TENG is capable of lighting eight light-emitting diodes.</P> [FIG OMISSION]</BR>
Zhu, Jianxiong,Guo, Xiaoyu,Meng, Dehuan,Cho, Minkyu,Park, Inkyu,Huang, Run,Song, Weixing The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.34
<P>In this paper, we report a flexible comb electrode triboelectric-electret coupling nanogenerator using a separated friction microfiber object for self-powered position, motion direction and acceleration tracking sensing and its energy harvesting. The power was generated from the coupling of the electrostatic and triboelectric effects among a separated triboelectric object, a polytetrafluoroethylene (PTFE) film and interdigital electrodes. Under an acceleration of 1 m s<SUP>−2</SUP>, we found that the corona charged PTFE film with a sliding motion reached ∼3 times more short-circuit current (<I>I</I>sc) and ∼6 times more open-circuit voltage (<I>V</I>oc) than the PTFE film without corona charges, respectively. The device can be a good self-powered acceleration tracking sensor, where the reasons were a stability voltage out during the process of separated components frictions and a numerical relationship of <I>I</I>sc with increased accelerations. Moreover, potential applications using several different separated materials such as a bulk of carbon microfibers, a finger sliding with a nylon glove, and water microdrops were used to show the energy harvesting of various friction materials and their effective contact area. It was found that a much larger contact area “finger” sliding showed a <I>V</I>oc of ∼45 V, whereas a smaller contact area “microdrop” sliding on the prototype presented a maximum peak <I>V</I>oc of ∼1.8 V.</P>
Multi-scale Local Difference Directional Number Pattern for Group-housed Pigs Recognition
( Weijia Huang ),( Weixing Zhu ),( Zhengyan Zhang ),( Yizheng Guo ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.9
In this paper, a multi-scale local difference directional number (MLDDN) pattern is proposed for pig identification. Firstly, the color images of individual pig are converted into grey images by the most significant bits (MSB) quantization, which makes the grey values have better discrimination. Then, Gabor amplitude and phase responses on different scales are obtained by convoluting the grey images with Gabor masks. Next, by calculating the main difference of local edge directions instead of traditionally edge information, the directional numbers of Gabor amplitude and phase responses are encoded. Finally, the block histograms of the encoded images are concatenated on each scale, and the maximum pooling is adopted on different scales to avoid the high feature dimension. Experimental results on two pigsties show that MLDDN impressively outperforms the other widely used local descriptors.