| 1. | The distributions of the values of fluctuating pressure conform to the law of normal distribution ; and the dominant frequency is low frequency
脉动压强幅值分布符合正态分布规律，优势频率为低频。 |
| 2. | The results show that the dominant frequency bands of blast vibration signals tend to be low , and its frequency band becomes wider
结果表明，爆破震动信号在传播过程中，其主振频带有往低频发展的趋势，且宽度增加。 |
| 3. | The dominant frequency increased as increase of the pear firmness , and decreased as increase of the pear mass
经分析，主响应频率随坚实度的增加而变大、随质量的增加而变小，主响应频率与质量、坚实度有较好的相关性。 |
| 4. | Flow separation produces pressure fluctuations of large amplitudes , possibly with the dominant frequencies differ from up - stream blade wake passing frequency and its harmonics
尾缘气流分离产生的压力波动频谱中含有上游叶片尾迹频率及其倍频的分量，但其频谱可能比较复杂，并非单一地受上游叶片尾迹影响。 |
| 5. | As a result of the analysis , the dominant frequency was significantly affected by the pear firmness and mass , while the excitation point , detected point , excitation intensity and impacting material did not
结果表明，不同测点、材料、激励点和速度对响应主频率没有较大影响，而质量、坚实度的影响则显著。 |
| 6. | The proposed approach can effectively monitor the changing trends of the dominant frequency and energy as well as the process variable contributions , and is feasible for non - stationary process monitoring , fault detection and localization
该方法能有效地监控过程系统中主导成分的频率、能量的变化趋势以及过程变量的贡献度，适合于非稳态过程监控以及故障检测与定位。 |
| 7. | It is considered that when the dominant frequencies of these dynamics components are close to the natural frequencies of the friction system , the system will show a resonant behavior and emit associated noise
当动态摩擦力频率接近摩擦系统的自然频率时，系统就发生摩擦振动从而发射噪声。根据这个假设，从摩擦学的角度解释了摩擦噪声一般发生在摩擦系数比较大的区域的原因。 |
| 8. | The inversion ' s resolution is restricted by seismic sampling rate , dominant frequency and bandwidth used a practical model to prove , and two difference concepts are put forward between seismic resolution and stratigraphic resolution
用实际模型论证反演的分辨率与地震资料分辨率的关系，认为反演的分辨率受地震资料的采样率、主频和有效频带的限制，并提出地震分辨和地层分辨两个不同的概念。 |
| 9. | On the rotor blade pressure surface , the dominant frequencies of unsteady surface pressure are the up - stream blade wake passing frequency and its harmonics , and the amplitudes of pressure fluctuations decrease from leading edge to trailing edge
转子叶片吸力面非定常压力受叶片附面层和上游叶片尾迹共同影响，其主导频率为上游叶片尾迹频率及其倍频，但是在吸力面前部气流加速区压力波动幅度沿流向增大，而在吸力面后部气流减速区压力波动幅度沿流向减小。 |
| 10. | In light of the limitation of fast fourier transform ( fft ) for the method of traditional spectrum analysis to analyze the unsteady signal , wavelet and wavelet analysis are made for the typical unsteady process signal of starting up and shut down with the good characteristic of simultaneous localization in both the time and the frequency domains based on the field test on the vibration of two - row placed units in lijiaxia hydropower station , in which the signal is decomposed into different frequency band , and then the weak signal is caught and the dominant frequency is picked up for the analysis of the vibration source
摘要基于李家峡水电站双排机组振动的现场试验研究，并且针对传统频谱分析方法傅立叶变换( fft )对于非平稳信号已力不从心这一缺陷，利用小波分析方法在时域和频域上同时具有良好的局部化性质，通过对开停机这一典型非平稳过程信号进行小波及小波包分析，将其分解到不同频带内，获取微弱信息和提取优势频率，并对其作振源分析，得出开停机初始时刻因水流不稳均出现强烈的振动现象，且低频段信号能量最大，开停机过程水流脉动压力和尾水涡带摆动是引起定子基础振动的主要原因。 |
