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41.
电力系统维护是电力系统稳定运行的重要保障,应用智能算法的无人机电力巡检则为电力系统维护提供便捷。电力线提取是自主电力巡检以及保障飞行器低空飞行安全的关键技术,结合深度学习理论进行电力线提取是电力巡检的重要突破点。本文将深度学习方法用于电力线提取任务,结合电力线图像特点嵌入改进的图像输入策略和注意力模块,提出一种基于阶段注意力机制的电力线提取模型(SA-Unet)。本文提出的SA-Unet模型编码阶段采用阶段输入融合策略(Stage input fusion strategy, SIFS),充分利用图像的多尺度信息减少空间位置信息丢失。解码阶段通过嵌入阶段注意力模块(Stage attention module,SAM)聚焦电力线特征,从大量信息中快速筛选出高价值信息。实验结果表明,该方法在复杂背景的多场景中具有良好的性能。 相似文献
42.
《Ceramics International》2022,48(16):23341-23347
In recent years, the rapid development of Li(NixCoyMn1-x-y)O2 (LNCM) materials for application in ternary lithium-ion batteries has led to an increased demand for refractory kiln saggars in industries. However, saggars used for firing ternary Li-ion battery cathode materials are often subjected to severe corrosion and spalling. To investigate the damage mechanism of the saggar materials, non-contact corrosion experiments were designed to study the effects of the precursor additions, calcination temperature, and number of calcinations during the interaction between mullite saggar and LNCM materials. The phase composition and microstructure of the mullite saggar specimens before and after corrosion were characterized using X-ray diffraction and scanning electron microscopy, respectively, to obtain a comprehensive understanding of the causes of the deterioration of mullite saggar materials during corrosion. 相似文献
43.
探索五种异喹啉类生物碱抗肝癌的作用机制。借助TCMSP、String、venny数据库与WebGestalt在线分析软件获取靶点并进行蛋白互作网络(PPI)、基因本体(GO)、基因相互作用(KEGG)功能富集分析,利用Cytoscape软件构建网络。同时查阅文献并进行归纳、整理和分析得到小檗碱型中的小檗碱、双苄基类生物碱的粉防己碱、苯菲啶喹啉类的血根碱、吗啡烷类中的青藤碱和吡咯菲里啶中的石蒜碱等几种常见的生物碱,根据结构作用机制阐述每一类代表性异喹啉类生物碱治疗肝癌的潜力及抗肝癌作用机制。五个活性成分共筛选得到52个作用靶标如p53(抑癌基因)、NCOA2(核受体共激活剂2)、IL-2(白介素2),主要涉及钙离子信号通路、雌激素受体信号通路和PI3K/Akt信号传导途径等通路。通过网络药理学和文献收集证实异喹啉类生物碱可能参与调控PI3K-Akt通路等,可以通过多靶点、多通路对肝癌产生治疗作用,为进一步研究异喹啉类生物碱抗肝癌的临床研究提供参考和依据。 相似文献
45.
通过压实试验、无侧限抗压强度试验和劈裂试验,分析不同木质纤维含量、水泥含量和固化时间对软土力学性能的影响规律,探讨木质纤维、水泥改良软土的微观机制。结果表明,木质纤维的加入对水泥改良软土的击实特性有显著的影响;木质纤维与水泥可有效改善土体的抗压和劈裂抗拉强度,随着木质纤维含量的增加,改良土的抗压和劈裂抗拉强度呈现出明显的“驼峰”现象,并在木质纤维含量为0.25%时最大;木质纤维与水化产物、软土颗粒形成互锁效应,增大了改良土的摩擦力,同时木质纤维还承担一定的拉伸强度,使改良土的劈裂强度增加。 相似文献
46.
Raheleh Nikonam M. Martin D. Pugh Robin A.L. Drew 《Journal of the European Ceramic Society》2019,39(4):915-927
In porous reaction bonded silicon nitride, whiskers normally grow in globular clusters as the dominant morphology and deteriorate the pore interconnectivity. However, the ceramic microstructure was significantly transformed with the addition of MgO; specifically, the morphology was modified to a combination of matte and hexagonal grains. Microstructural observation along with thermodynamic studies suggest that MgO interfered with the presence and nitridation of SiO(g). Consequently, rather than being involved in the whiskers’ formation, surface silica instead reacted with volatile MgO to form intermediate products. Through these reactions, whisker formation was blocked, and a porous interconnected structure formed which was confirmed by 3D tomography. After heat-treatment at 1700 °C, β-Si3N4 crystallized in a glassy matrix containing magnesium. Resulting samples had an open-pore structure with porosity of 74–84 vol. %, and density of 0.48-0.75 g.cm?3. Combination of high porosity and pore size of <40 μm led to compressive strengths of 1.1–1.6 MPa. 相似文献
47.
48.
Yunqi Li Jing Li Yang-Gang Wang Xiran Chen Mingtao Liu Zhong Zheng Xihong Peng 《International Journal of Hydrogen Energy》2021,46(24):13273-13282
In this work, density functional theory (DFT) calculations were used to investigate the mechanism of carbon corrosion on nitrogen-doped carbon support. Free energy diagrams were generated based on three proposed reaction pathways to evaluate corrosion mechanisms. The most energetically preferred mechanism on nitrogen-doped carbon was determined. The results show that the step of water dissociation to form #OH was the rate-determining step for gra-G-1N (graphene doped with graphitic N) and pyrr-G-1N (graphene doped with pyrrolic N). As for graphene doped with pyridinic N, the step of C#OC#O formation was critical. It was found that the control of nitrogen concentration was necessary for precisely designing optimized carbon materials. Abundance of nitrogen moieties aggravated the carbon corrosion. When the high potential was applied, specific types of graphitic N and pyridinic N were found to be favorable carbon modifications to improve carbon corrosion resistance. Moreover, the solvent effect was also investigated. The results provide theoretical insights and design guidelines to improve corrosion resistance in carbon support through material modification by inhibiting the adsorption of surface oxides (OH, O, and OOH). 相似文献
49.
Tao Wang Weihui Jiang Jianmin Liu Guo Feng Lifeng Miao Ting Chen Qian Wu 《Ceramics International》2019,45(4):4514-4519
High quality zirconia whiskers have been successfully prepared by molten salt method, using zirconium oxychloride (ZrOCl2·8H2O) and sodium phosphate tribasic dodecahydrate (Na3PO4·12H2O) as precursor and molten salt, respectively. The effects of types of molten salt and heat treatment temperature on the formation of zirconia whiskers were characterized by XRD, Raman, DTA-TG, FE-SEM, TEM, SAED and HR-TEM. When Na3PO4·12H2O is utilized as molten salt and the heat treatment temperature is 900?°C, the as-prepared zirconia whiskers with length ranging from 4?µm to 8?µm show an average aspect ratio of 25. The obtained ZrO2 whiskers with monoclinic structure are elongated along [010] direction and exhibit a smooth surface with no distinct defects. The XRD and Raman results reveal that the phase transformation from tetragonal zirconia to monoclinic zirconia occurs with the increased crystal size and the water quenching treatment can significantly reduce the content of sodium zirconium phosphate [Na9–4×Zrx(PO4)3] in the final product. The growth mechanism of zirconia whiskers is supposed to be a dissolution-precipitation process. Since the sodium zirconium phosphate [Na9–4×Zrx(PO4)3] effectively promotes the dissolution of zirconia in liquid molten salt, zirconia can grow into zirconia whiskers according to its anisotropy. 相似文献
50.
Qian Li Xiaoman Zhu Yanli Xie Shilin Ren 《International Journal of Food Science & Technology》2021,56(1):178-184
This study investigated the antifungal activity and the potential antifungal mechanisms of 2-hydroxy-4-methoxybenzaldehyde (HMB) against Aspergillus flavus (A. flavus). The minimum inhibitory concentration (MIC) of HMB in preventing spore germination was 70 μg mL−1. HMB at MIC disrupted cell wall integrity by reducing the number of septa by 86.66% (P < 0.05) in mycelia and increased cell membrane permeability by about 14-fold (P < 0.05) evidenced by propidium iodide (PI) staining. Furthermore, HMB at MIC inhibited respiration by 33.33%. These results revealed that the antifungal activity of HMB against A. flavus could be attributed to the damaged cell wall integrity, cell membrane permeability and respiration metabolism. What’s more, A. flavus was completely restrained in corn kernels due to HMB. Therefore, HMB could be applied as an effective antifungal agent. 相似文献