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西瓜音频特性分析方法讨论
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作者 曹旭东 《科技信息》 2011年第23期I0161-I0162,共2页
使用敲击获得西瓜的音频特性从而反映其成熟信息是一种常见的方法,但利用音波传感器采集的音频信号却不能很准确的反映西瓜的成熟度。音频特性分析分为音波振型比较、音波功率谱密度分析、固有频率(基频)测定、有限元模型计算、频带幅... 使用敲击获得西瓜的音频特性从而反映其成熟信息是一种常见的方法,但利用音波传感器采集的音频信号却不能很准确的反映西瓜的成熟度。音频特性分析分为音波振型比较、音波功率谱密度分析、固有频率(基频)测定、有限元模型计算、频带幅值向量(BMV)计算等方法,本文从理论和结果上对其进行了比较,以探讨其改进方向。 展开更多
关键词 音频特性分析 西瓜成熟度
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Spectral analysis of bowel sounds in intestinal obstruction using an electronic stethoscope 被引量:14
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作者 Siok Siong Ching Yih Kai Tan 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第33期4585-4592,共8页
AIM: To determine the value of bowel sounds analysis using an electronic stethoscope to support a clinical diagnosis of intestinal obstruction. METHODS: Subjects were patients who presented with a diagnosis of possibl... AIM: To determine the value of bowel sounds analysis using an electronic stethoscope to support a clinical diagnosis of intestinal obstruction. METHODS: Subjects were patients who presented with a diagnosis of possible intestinal obstruction based on symptoms, signs, and radiological findings. A 3MTH Littmann Model 4100 electronic stethoscope was used in this study. With the patients lying supine, six 8-second recordings of bowel sounds were taken from each patient from the lower abdomen. The recordings were analysed for sound duration, soundto-sound interval, dominant frequency, and peak frequency. Clinical and radiological data were reviewed and the patients were classified as having either acute, subacute, or no bowel obstruction. Comparison of bowel sound characteristics was made between these subgroups of patients. In the presence of an obstruction, the site of obstruction was identified and bowel calibre was also measured to correlate with bowel sounds. RESULTS: A total of 71 patients were studied during the period July 2009 to January 2011. Forty patientshad acute bowel obstruction (27 small bowel obstruction and 13 large bowel obstruction), 11 had subacute bowel obstruction (eight in the small bowel and three in large bowel) and 20 had no bowel obstruction (diagnoses of other conditions were made). Twenty-five patients received surgical intervention (35.2%) during the same admission for acute abdominal conditions. A total of 426 recordings were made and 420 recordings were used for analysis. There was no significant difference in sound-to-sound interval, dominant frequency, and peak frequency among patients with acute bowel obstruction, subacute bowel obstruction, and no bowel obstruction. In acute large bowel obstruction, the sound duration was significantly longer (median 0.81 s vs 0.55 s, P = 0.021) and the dominant frequency was significantly higher (median 440 Hz vs 288 Hz, P = 0.003) when compared to acute small bowel obstruction. No significant difference was seen between acute large bowel obstruction and large bowel pseudoobstruction. For patients with small bowel obstruction, the sound-to-sound interval was significantly longer in those who subsequently underwent surgery compared with those treated non-operatively (median 1.29 s vs 0.63 s, P < 0.001). There was no correlation between bowel calibre and bowel sound characteristics in both acute small bowel obstruction and acute large bowel obstruction. CONCLUSION: Auscultation of bowel sounds is nonspecific for diagnosing bowel obstruction. Differences in sound characteristics between large bowel and small bowel obstruction may help determine the likely site of obstruction. 展开更多
关键词 Bowel sounds Intestinal obstruction Spectral analysis Electronic stethoscope
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