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To develop a measurement system for monitoring partial discharge (PD) without the effect of external interferences,an algorithm of PD signal extraction based on wavelet transform with Teager's energy operators was presented.Acoustic signal generated by PD was selected to remove excessive interfering signals and electromagnetic interferences.Acoustic signals were collected and decomposed into 10 levels by wavelet transform into approximation and detail components."Daubechies 25"was proved to be the most suitable mother wavelet for the extraction of PD acoustic signals.Compared with conventional wavelet denoising method,Teager's energy operators were adopted to the PD signal reconstruction and the signal to noise ratio was pulse amplitude. 相似文献
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Acoustic signals from diesel engines contain useful information but also include considerable noise components.To extract information for condition monitoring purposes, continuous wavelet transform (CWT) is used for the characterization of engine acoustics. This paper first reviews CWT characteristics represented by short duration transient signals.Wavelet selection and CWT are then implemented and wavelet transform is used to analyze the major sources of the engine front's exterior radiation sound. The research provides a reliable basis for engineering practice to reduce vehicle sound level.Comparison of the identification results of the measured acoustic signals with the identification results of the measured surface vibration showed good agreement. 相似文献
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Acoustic signals from diesel engines contain useful information but also include considerable noise components. To extract information for condition monitoring purposes, continuous wavelet transform (CWT) is used for the characterization of engine acoustics. This paper first reviews CWT characteristics represented by short duration transient signals. Wavelet selection and CWT are then implemented and wavelet transform is used to analyze the major sources of the engine front's exterior radiation sound. The research provides a reliable basis for engineering practice to reduce vehicle sound level. Comparison of the identification results of the measured acoustic signals with the identification results of the measured surface vibration showed good agreement. 相似文献
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本文为广西桂西壮族地区"埋蚂(虫另)"节的调查报告。对于埋蚂(虫另)节的祭祀礼仪、壮族的舞蹈、壮 族的传统游戏均作了重点式的介绍。文末并附有"壮族蚂(虫另)歌",详细述说蚂(虫另)的传奇事迹和悲惨遭遇。 相似文献
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试论蛙类生活习性的多样性 总被引:1,自引:0,他引:1
丁建发 《宁德师专学报(自然科学版)》2004,16(4):361-363
从捕食、冬眠、繁殖等方面探讨蛙类生活习性的多样性.蛙类幼体(蝌蚪)的食性有杂食性、植食性和肉食性3种类型,成体主要以活动的动物为主食.各种蛙冬眠期的长短和起止时间不相同,同一种蛙,开始冬眠和苏醒的迟早,也因地区而异.1只性成熟的雌蛙一年可产卵2次或2次以上;各种蛙类每1雌体的1次产卵数量悬殊很大;大多数蛙类的产卵期为每年的4~8月间,但一年四季都有蛙类产卵;蛙类的产卵场所可分为水内产卵和水外产卵2大类;蛙类产卵的全过程包括呜叫求偶、抱对、产卵动作等. 相似文献
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《中学生英语》2019,(38)
<正>Phonetics is a fundamental branch of linguistics and itself has three different aspects. Articulatory Phonetics—describes how vowels and consonants are produced or "articulated" in various parts of the mouth and throat. Acoustic Phonetics—a study of how speech sounds are transmitted:when sound travels through the 相似文献
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有声语言是在课堂教学中发出声音的语言,它在教学活动中起着十分重要的作用。任何教育活动都离不开有声语言。在课堂教学中,有声语言的运用要做到准确精练,生动活泼,通俗易懂,和谐适听。 相似文献
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The article highlights the biological significance of songs and calls in birds. The structural diversity of songs and its
relevance for social behaviour are described. Acoustic communication plays an important role in the life of birds and has
proven useful in establishing phylogenetic and evolutionary relationships among species. 相似文献
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钟苏 《深圳职业技术学院学报》2006,5(2):13-16
提出了一种采用SAW可编程抽头延时线相关器对MSK直序扩频系统进行相干解调的方法,建立了系统仿真模型,利用SystemView仿真软件进行了系统仿真。通过对仿真结果的分析,为硬件系统设计提供了原理上的可行性验证,为硬件调试提供了经验和参考。 相似文献
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论述英语广告已成为商业宣传的重要手段。广告词的音韵美是市场竞争的需要,押韵是诗歌常用来美化音律的手法,广告语言也不时加以移植。音韵美与播音的完美结合,能更好地揭示商品内涵,树立企业品牌,扩大商品销售。 相似文献
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陈敢 《南宁师范高等专科学校学报》2010,27(4):7-9
花山文化是壮族文化的重要组成部分。它生动真切地记录了壮族先民跋涉求索的人生历程,彰显了欧骆人雄强的生命力,融注了他们对青蛙特有的深情,并视之为民族图腾。 相似文献
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蒙古语韵律特征研究是 19世纪中叶开始的 ,但进展不大。而研究某语言或方言的韵律特征最可行的方法是建立该语言或方言的韵律特征声学参数数据库 ,并归纳相应的模式及其变化规则。经过两年多的努力 ,我们已建立了规模较大的《蒙古语韵律特征声学参数数据库》,它为归纳蒙古语韵律特征声学模式打下了坚实的基础 相似文献
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丁建发 《宁德师专学报(自然科学版)》2005,17(1):23-24
常温条件下,大树蛙早期发育从受精卵到蝌蚪孵化需6d左右,卵群形态、孵化方式等与大多数无尾两栖类有别;胚胎发育、变态发育与其它无尾两栖类相似;在实验室人工饲养下,蝌蚪在孵化后的第29d长出后肢,第36d长出前肢,第43d完成变态发育. 相似文献
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精品多媒体网络课件开发与制作研究 总被引:1,自引:0,他引:1
高校的多媒体教学应用越来越广泛,但真正能用于教学且能发挥良好教学效果的多媒体网络课件却不多见。因此,开发制作出精品多媒体网络课件成为当前深化推广应用多媒体教学的当务之急。本文以《音响技术》多媒体网络课件的设计、开发与制作实践为例,探讨了多媒体网络课件开发制作的一些方法、技巧和模式,以指导和帮助教师提高课件制作水平。 相似文献