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变压器振动波谱在线监测的可行性研究 被引量:9
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作者 陈健 丁巧林 李中 《变压器》 北大核心 2011年第9期32-34,共3页
分析了变压器振动波谱的产生机理,对利用振动波谱法监测变压器故障的可行性进行了研究,
关键词 电力变压器 振动波谱 在线监测
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变压器振动波谱特征信号的判别方法研究 被引量:1
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作者 杨雪漫 张炜 +2 位作者 邬蓉蓉 张玉波 陆一凡 《电工材料》 CAS 2019年第2期29-33,42,共6页
通过实测变压器的振动波谱信号,提出了识别位移特征的判据和布点方式,并用以分析绕组及铁心状态的嬗变过程。首先,利用压电式加速度振动传感器研制了振动信号测量装置,并用于提取变压器器身、冷却器的振动波谱信号。其次,针对测点及采... 通过实测变压器的振动波谱信号,提出了识别位移特征的判据和布点方式,并用以分析绕组及铁心状态的嬗变过程。首先,利用压电式加速度振动传感器研制了振动信号测量装置,并用于提取变压器器身、冷却器的振动波谱信号。其次,针对测点及采样方式分析了不同振动源的传播途径、作用关系。最后,针对不同测点振动波谱信号的时域波形、频谱和加速度,总结铁心、绕组的压紧程度特征。实测结果显示,变压器振动波谱特征测试结果符合推算结果,可用于跟踪判断变压器铁芯、绕组的状态变化。 展开更多
关键词 电力变压器 振动波谱 时域波形 频谱 振动传感器
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空心纳米球耦合到基底的热力学性质研究
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作者 尹学爱 马国利 《人工晶体学报》 EI CAS CSCD 北大核心 2011年第3期807-811,共5页
应用弹性波理论研究不同的空心S i纳米球弱耦合到半无限长的基底上在微扰近似下的振动态密度,结果发现在低频下耦合空心球的振动模有明显的展宽和改变。通过求解声子传播函数的Dyson方程得到空心球的振动态密度,并进一步研究了空心球的... 应用弹性波理论研究不同的空心S i纳米球弱耦合到半无限长的基底上在微扰近似下的振动态密度,结果发现在低频下耦合空心球的振动模有明显的展宽和改变。通过求解声子传播函数的Dyson方程得到空心球的振动态密度,并进一步研究了空心球的热力学性质。 展开更多
关键词 空心纳米球 振动波谱 态密度 热力学性质
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Structural and Vibrational Study of 2-(Quinolin-8-yloxy)-Acetic Acid based on FT-IR-Raman Spectroscopy and DFT Calculations 被引量:1
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作者 Gerardo R. Arganaraz Elida Romano +1 位作者 Juan Zinczuk Silvia A. Brandan 《Journal of Chemistry and Chemical Engineering》 2011年第8期747-758,共12页
We have prepared the 2-(quinolin-8-yloxy)-acetic acid and characterized it by infrared and Raman spectroscopies in the solid phase. The Density Functional Theory (DFT) method, together with the 6-31G^* and 6-311... We have prepared the 2-(quinolin-8-yloxy)-acetic acid and characterized it by infrared and Raman spectroscopies in the solid phase. The Density Functional Theory (DFT) method, together with the 6-31G^* and 6-311++ G^** basis sets, show that three stable molecules, for the anhydrous and monohydrated compounds were theoretically determined in the gas phase, and that probably the two more stable conformations are present in the solid phase of the monohydrated compound. The harmonic vibrational wavenumbers for the optimized geometries were calculated at B3LYP/6-31G^*and B3LYP/6-311++G^** levels. For a complete assignment of all the observed bands in the vibrational spectra the DFT calculations were combined with Pulay's scaled quantum mechanical force field (SQMFF) methodology in order to fit the theoretical Wavenumber values to the experimental ones. The characteristics of the electronic delocalization of all structures of both forms were performed by using natural bond orbital (NBO), while the corresponding topological properties of electronic charge density are analysed by employing Bader's atoms in molecules theory (AIM). 展开更多
关键词 2-(Quinolin-8-yloxy)-acetic acid vibrational spectra molecular structure force field DFT calculations
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Resonance Raman Spectroscopic and Theoretical Study of Geometry Distortion of Thiourea in 2^1A State
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作者 张海波 赵彦英 郑旭明 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第1期1-10,I0003,共11页
The A-band resonance Raman spectra of thiourea were obtained in water and acetonitrile solution. B3LYP/6-311++G(3df,3pd) and RCIS/6-311++G(3df,3pd) calculations were done to elucidate the ultraviolet electroni... The A-band resonance Raman spectra of thiourea were obtained in water and acetonitrile solution. B3LYP/6-311++G(3df,3pd) and RCIS/6-311++G(3df,3pd) calculations were done to elucidate the ultraviolet electronic transitions, the distorted geometry structure and the saddle point of thiourea in 21A excited state, respectively. The resonance Raman spectra were assigned. The absorption spectrum and resonance Raman intensities were modeled using Heller's time-dependent wavepacket approach to resonance Raman scattering. The results indicate that largest change in the displacement takes place with the C--S stretch mode u6 (|△|=0.95) and noticeable changes appear in the H5N3H6+H8N4H7 wag v5 (|△|=0.19), NCN symmetric stretch^-C--S stretch+N3H6+H8N4 wag v4 (|△|=0.18), while the moderate intensities of 2-15 and 4-15 are mostly due to the large excited state frequency changes of v15, but not due to its significant change in the normal mode displacement. The mechanism of the appearance of even overtones of the S-CN2 out of plane deformation is explored. The results indicate that a Franck-Condon region saddle point is the driving force for the quadric phonon mechanism within the standard A-term of resonance Raman scattering, which leads to the pyramidalization of the carbon center and the geometry distortion of thiourea molecule in 21A excited state. 展开更多
关键词 THIOUREA Excited state structural dynamics Resonance Raman Timedependent wavepacket approach Density functional theory
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Structural safety criteria for blasting vibration based on wavelet packet energy spectra 被引量:14
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作者 Zhong Guosheng Li Jiang Zhao Kui 《Mining Science and Technology》 EI CAS 2011年第1期35-40,共6页
Given multi-resolution decomposition of wavelet packet transforms,wavelet packet frequency band energy has been deduced from different bands of blasting vibration signals.Our deduction reflects the total effect of all... Given multi-resolution decomposition of wavelet packet transforms,wavelet packet frequency band energy has been deduced from different bands of blasting vibration signals.Our deduction reflects the total effect of all three key elements(intensity,frequency and duration of vibration)of blasting vibration. We considered and discuss the dynamic response of structures and the effect of inherent characteristics of controlled structures to blasting vibration.Frequency band response coefficients for controlled structures by blasting vibration have been obtained.We established multi-factor blasting vibration safety criteria,referred to as response energy criteria.These criteria reflect the total effect of intensity, frequency and duration of vibration and the inherent characteristics(natural frequency and damping ratio)of dynamic responses from controlled structures themselves.Feasibility and reliability of the criteria are validated by an example. 展开更多
关键词 Blasting vibrationWavelet packet transformResponse energySafety criteria
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