排序方式: 共有114条查询结果,搜索用时 31 毫秒
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针对变压器铁心松动故障诊断中现有的信号处理方法存在模态混叠或受参数影响等问题,引入了经验小波变换方法,并提出了直接阈值边界划分方法对经验小波变换进行改进。对不同边界划分方法进行了对比研究,验证了直接阈值法可将信号的各个主要成分都能准确划分到各自分量之中的优点。以铁心松动故障为实例,通过计算改进型经验小波变换之后的能量熵来判别铁心的松动状态,发现随着铁心压紧力的减小,EWT能量熵明显增加,并且压紧力矩在20N·m左右时发生突变。用改进型经验小波变换的故障诊断方法可有效准确地判断铁心松动故障,对实际运行中变压器的故障监测有重要意义。 相似文献
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在双螺杆挤出机上通过原位增容反应挤出制备了聚酰胺6(PA6)/高密度聚乙烯(PE-HD)共混物。通过力学性能测试、扫描电子显微镜观察和Molau实验,研究了PE-HD含量对PA6/PE-HD共混物的力学性能和体系增容作用的影响。结果表明,PE-HD与马来酸酐(MAH)在挤出共混过程中原位生成了PE-HD-g-MAH,其对PA6/PE-HD共混物有较好的增容作用;PA6/PE-HD共混物的力学性能与界面形态均有较大改善,吸水率有所降低。 相似文献
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We have fabricated an organic photocoupler with organic light-emitting diodes (OLEDs) with 520 nm emissive wavelength as the input light source and a photodiode (PD) based on poly(3-hexylthiophene) (P3HT):1-(3-methoxycarbonyl)propyl- 1-phenyl-(6,6)-C61 (PCBM) as the detector. The influences of buffer layer (PEDOT:PSS) on output current (Iout), current transfer ratio (CTR) and time response characteristics of the photocoupler device were studied. Through our experiments, It is found that the output current linearly increases with the input current, the max output current and CTR of the devices with PEDOT:PSS buffer layer are 2 times and 7 times than that of the devices without buffer layer respectively, which show that the existence of buffer layer can enhance the output photocurrent efficiently. Moreover, the existence of PEDOT:PSS eliminates the time delay of the devices. 相似文献
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经过近几年的运行实践表明,小浪底水电站水轮机所采取的抗磨蚀措施是基本成功的。本文总结了小浪底电站在水轮机抗磨蚀方面所采用的技术措施,以促进这些措施的推广应用。 相似文献