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番茄聲發(fā)射信號功率譜特征分析
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科技部星火計劃重點項目(2015GA600005)和北京市農林科學院設施園藝科技創(chuàng)新團隊項目(JNKST201615)


Power Spectrum Characteristics Analysis for Acoustic Emissions Signal of Tomato
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    摘要:

    采用番茄品種“佳麗14”為試材,,采集盆栽番茄聲發(fā)射信號進行短時傅里葉變換與頻譜分析,,獲取番茄在水分虧缺條件下聲發(fā)射信號,、土壤含水率及光合特征的連續(xù)變化規(guī)律及相互關系,。依據土壤含水率變化將試驗過程劃分為DAY1,、DAY2,、DAY3和DAY4共4個階段,。試驗結果表明,,番茄聲發(fā)射信號發(fā)生頻次呈現(xiàn)出規(guī)律性,,高峰期發(fā)生時間為每天10:00—16:00,,幅值分布在40~60dB;番茄聲發(fā)射信號的主頻和中心頻率分布于250~375kHz,,隨著土壤含水率的降低,,其主頻與中心頻率無顯著變化;DAY1的第1共振峰頻率分布在0~125kHz,,第2共振峰,、第3共振峰位于250~375kHz,DAY2,、DAY3和DAY4的第1,、第2、第3共振峰均分布在250~375kHz,;從共振峰幅值上看,,DAY1的排列順序為第3、第2,、第1共振峰,;DAY2和DAY4的次序與之相反。番茄葉片凈光合速率變化呈現(xiàn)單峰曲線,,在中午12:00出現(xiàn)峰值,,番茄的胞間CO2濃度呈現(xiàn)先增后減的變化趨勢。綜合分析番茄聲發(fā)射信號,、土壤含水率和光合特征參數變化可知,,番茄灌溉初期與灌水后期的聲發(fā)射信號共振峰頻率、幅值的變化規(guī)律不同,,其與水分虧缺程度密切相關,,與番茄凈光合速率、胞間CO2濃度和光合作用具有相關性,。通過番茄聲發(fā)射信號功率譜特征分析可為番茄聲發(fā)射特性研究提供一種分析方法,。

    Abstract:

    Taking tomato variety of ‘Jiali14’ as experimental materials, the relationship among the acoustic emissions signal, soil water contents and photosynthetic characteristic parameters of tomato under water deficit was analyzed. The short-time Fourier transform and power spectrum analysis computed by LabVIEW 2014 were employed to examine the spectrum characteristics of the collected AE signals. The whole process of water deficit was approximately divided into four stages: DAY1, DAY2, DAY3 and DAY4 according to the soil water contents. The results showed that characteristics for AEs during the water deficit period were presented by a regular change pattern, while the peak time was 10:00—16:00 and the amplitude was 40~60dB. Power spectrum for acoustic emissions of tomato was a phenomenon observed in characteristic parameters with dominant frequency (fp), central frequency (fa) and formants. The frequencies of fp, fa and the second, third resonance peaks of DAY1 were distributed at 250~375kHz, where the first resonance peak of DAY1 was distributed mainly at 0~125kHz. The first, second and third resonance peaks of DAY2, DAY3 and DAY4 were all centralized at 250~375kHz. From the amplitude of resonance peaks, the arrangement of DAY1 was the third, second, and first formant, but the order of formants for DAY2 and DAY4 were opposite of DAY1. A single peak curve was existed with net photosynthetic rate of tomato, and the peak value Pn occurred at 12:00, whereas the intercellular CO2 concentrations were increased firstly and then decreased with the decrease of soil water contents. Although the changes of amplitude and frequencies of resonance peaks for acoustic emissions of tomato in initial irrigation stage and late irrigation stage were different, a good correspondence between AE outcomes and experimental observations of the net photosynthetic rate, intercellular CO2 concentrations and photosynthetic performances was obtained and discussed. This result may provide a new monitoring method for acoustic emissions characteristics of water deficit through power spectrum analysis.

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余禮根,李長纓,陳立平,薛緒掌,衛(wèi)如雪,郭文忠.番茄聲發(fā)射信號功率譜特征分析[J].農業(yè)機械學報,2017,48(10):189-194. YU Ligen, LI Changying, CHEN Liping, XUE Xuzhang, WEI Ruxue, GUO Wenzhong. Power Spectrum Characteristics Analysis for Acoustic Emissions Signal of Tomato[J]. Transactions of the Chinese Society for Agricultural Machinery,2017,48(10):189-194.

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  • 收稿日期:2017-06-22
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  • 在線發(fā)布日期: 2017-10-10
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