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最佳阻尼控制是一种结构参数(阻值向量)的最优化控制,设计简单。同步电机的励磁系统实现了该类控制后,具有极佳的动态性能指标。 相似文献
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向罗丹明6G(R6G)和锗钼杂多酸的甲苯浮选物(R6G)4GeMo12RO40中,加入0.01mol/L的氢氧化钠水溶液,使R6G+离子进入水相,并向其中加入与R6G颜色相近的四溴荧光素(TBF),形成等色染料离子对R6G·TBF再被甲苯浮选,将浮选物溶于丙酮,于530nm处进行光度测定,由于8个染料分子同时吸光,使本方法具有很高的灵敏度,=8.55×105,锗含量在0~0.085mg/L服从比尔定律,回收率为97%~106%,相对标准偏差RSD≤4.3%,用于铅锌矿、蔬菜中痕量锗的测定,得到了满意的结果 相似文献
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轨道电路是轨道信号的载体,是行车安全的可靠保障.铁路上通常采用测试轨道信号参数的方法来衡量轨道电路工作状态的好坏,并且对测试方法的实时性和准确性都有严格的要求.本文提出了一种轨道信号参数实时测试的新方法.轨道信号由机车底盘下面的感应器感应上来,经过隔离、滤波和放大,送至数字采集卡进行A/D采样;采样后的离散样本经FFT变换后,先进行频谱细化,再进行频谱校正处理;最后,根据频谱分布的对称性,得到信号的哪幅度和频率参数.系统的硬件结构和软件实现均采用了虚拟仪器技术.现场实验表明,该分析仪测试精度高,实时性好,满足所有的测试要求. 相似文献
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Y2O3: Eu nanocrystals were synthesized by EDTA complexing sol-gel process at a relatively low temperature, in which ethylen-diamine-tetraacetic acid (EDTA) and polyethylene glycol (PEG) were used as the chelating agent and polymerization agent respectively. Formation process of Y2O3:Eu and structure characterization were carried out by TG-DTA, XRD, SEM/EDX. The results show that pure cubic phase Y203: Eu nanocrystalsere is produced after the precursor calcinated at 600℃ for 2 h, and the crystallinity increases with increasing calcination temperature. The nanoparticles of the Y2O3: Eu are basically spherical in shape. The mean particle size increases from about 30 to 70 nm when the calcination temperature increases from 600 to 1000℃. The luminescent properties of phosphor were analyzed by measuring the excitation and emission spectra. The main emission peak of the sample is around 612 nm, resulting in a red emission. The emission intensity increases with the calcination temperature. Compared with microsized Y2O3: Eu phosphors prepared by a conventional method, nanosized Y2O3: Eu synthesized by the present work, gives and a clear red shift in the emission spectrum. Moreover, the quenching concentration of Eu is raised. 相似文献
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Nanoparticlesandnanoclustermaterialsareanewclassofadvancedmaterialsexhibit inguniquechemicalandphysicalpropertiescomparedtothoseoftheirbulkmaterials[1 ] .Y2 O3 :Euisanefficientred emissionphosphorwhichhasbeenusedinfluorescentlights (FL)andcathoderaytube (CRTs… 相似文献