时-频联合信号分析法能描述非稳态信号的频率如何随时间而变化，故它能使我们更好地理解信号的本质。
Joint time Frequency Analysis (JTFA) describes and determines how the frequencies of non stationary signals change over time. It offers a better understanding of nature of the signal.
目的本实验用显微硬度测量法，定量研究和评估人离体牙釉质在酸性饮料中的硬度变化，比较牙釉质在饮料中浸泡时间及浸泡频率对釉质表面硬度的影响。
Objective This in vitro study quantitatively assessed the effect of frequency and time span of immersion of human teeth in acidic soft drinks on enamel surface microhardness.
利用单元局部频率变化率法和单元模态应变能比法，对连续梁桥进行了损伤诊断的数值模拟研究。
Based on element local frequency change ratio method and element modal strain energy ratio method, numerical study is carried on to detect the damage of the bridge.
应用推荐