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In the course of recording heart sound, it is inevitable that many kinds of noise will be merged in the main signal. These kinds of noise disbennifit the heart sounds, even import awful influence to analysis result. So, before further processings of phonocardiographic records, noise must be suppressed. Because heart-sound is a highly nonstationary signal, this paper presents the application of adaptive filter method to the elimination of noise,and at the same time, employs the datum of heart-sound plot as the reference noise. With simulink, a modeling and simulation tool for dynamical systems, the model of LMS adaptive heart-sound enhancement is established.Tests prove this method makes effective denoising and heart-sound enhancement. 相似文献
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Heart sound is a highly nonstationary signal, and the Short-time Fourier Transform ation(STFT) is an effective method for this kind of signal to be analysed. Because of the nonstationarity of the phonocardiogram, it is important to maintain an analysing time window as short as possible to guaranty the stationarity hypothesis over small analysed segments. This will reduce the frequency resolution of the resulting spectrogram. However by adjusting the sliding time window, we can reach an acceptable result. The spectrogram is caculated by using first, short length sliding window to generate a temporal representation of the PCG, then longer length sliding window in order to generate a spectral representation of the PCG power. The resolution in such representations depend directly on the sliding window length. The temporal representation allows heart sounds and cardiac cycle durations to be measured. Whereas the spectrum, assuming a good frequency resolution, allows spectral characterization of each heart sound. The results we obtained on normal PCG signal show that the STFT analysis with different scale basis provides a clear comprehension of the cardiac events in both time and frequency domain. 相似文献
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Heart rate variability is a convenient tool to study the autonomic nervous system of human body. It is a focus of studying cardiovascular disease in clinic. The main spectral components are distinguished in the heart rate variability spectrum: ultra low frequency(ULF),very low frequency(VLF), low frequency(LF), high frequency(HF) components .While different part has different physiological meaning. This paper discusses the design of an effective digital filter for heart rate variability power spectral analysis,which provides a scientific measure of heart rate variability power spectral analysis in further studies and clinical applications. 相似文献
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Heart sound is a faint signal which is difficult to be acquired. This paper presents the methods for the heart sound acquisition used electret microphone,including the heart sound extraction project, principle, rules and the impedance conversion of microphone. In order to acquire the useful heart sound, the microphone is shielded by a special device. The clinical experiments have indicated that the first and second heart sound can be almost acquired by the microphone, but it is difficult for the third and fourth , which are affected by sex and bodily form. 相似文献
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为了研究金银花总黄酮提取液对心脏收缩功能的影响,本试验采用离体蛙心灌流技术,通过BL-420F生物机能实验系统,观察记录不同浓度金银花总黄酮提取液对离体蟾蜍心脏活动的影响。试验结果表明：用高浓度（2mg.mL-1）金银花总黄酮提取液灌流时,导致心脏猝停,用低浓度(2×10-1~2×10-6mg.mL-1)的金银花总黄酮提取液灌流离体心脏时,其心率和心肌张力都是下降的。t检验表明,对心率的影响差异显著 (P<0.05);对心肌张力的影响达到极显著水平（P<0.01)。本实验研究结果表明,金银花总黄酮提取液在一定范围内对离体蟾蜍心脏功能的影响表现为抑制作用,且对其心肌张力的影响更为明显。 相似文献
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云南黄心甘薯地方品种特性分析 总被引：1，自引：0，他引：1
１９９６～１９９７年对征集到的２４份云南黄心甘薯地方品种资源进行了农艺性状、生长特性、抗逆性、生产力及营养品质的分析、评价，结果表明：蒙自黄心、红鸡窝、普洱黄山芋、紫红皮、甘心红薯、路南红皮、东川白花等一批黄心地方品种生长势强、适应性强、块根产量高、品质优，开发利用潜力较大。 相似文献
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Heart sound is non-stationary signal, some of its important characteristics can be obtained by time - frequency analysis method. The criteria of different time-frequency representation concentricity of spectrogram, coverage, MSE and regularity of time envelope axe proposed, the performances of Short-time Fourier transform, Wigner - Ville distribution, continuous wavelet transform, and S transform in study on heart sound are compared based on these criteria , and concrete example of application is given. 相似文献
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In the utilization of the Kaiser Effect of AE as a method of estimating the gecstress in rock, it is very important to eliminate the noise induced at the ends cf a specimen, so sponge pads are put between the upper and lower end surfaces of specimens and bearing plates. In this paper, the attenuation behavior of sounds emitted by AE simulator and propagating in sponges are quantitatively measured. The eliminaion of noise by sponge effect is confirmed by the Kaiser Effect. 相似文献
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为了明确马占相思心腐病发生初期的病原菌种类,为病害的早期诊断和防治提供依据,笔者从广东省龙眼洞国营林场外表无症状的6年生马占相思树上采集病样36份,分离出3种担子菌,通过田间枝条接种、室内木块接种测定其致病性。结果显示,3种担子菌在6年生马占相思树1年生健康枝条上接种20天,枝条髓心变褐深度分别为5.0、2.4、7.0 cm;室内25℃下接种61天,木块腐朽质量损失分别为25.88%、31.48%、21.02%。对3种担子菌进行PCR扩增,测定核糖体DNA（rDNA）内转录间隔区（ITS）的序列,将测序结果在GenBank中进行同源性比对分析,结合形态特征,确定3种病原菌分别为Phanerochaete avellanea、Peniophora aurantiaca、Phlebia brevispora。得出结论：Phanerochaete avellanea、Peniophora aurantiaca和Phlebia brevispora具有侵染枝条和使木块腐朽的能力,是马占相思心腐病发生初期的病原菌。 相似文献
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ZHU Jia-fu~ 《保鲜与加工》2004,(7):50
Heart rate variability is an important index to express the tensility and balance of the parasympathetic-sympathetic nerve, and it is valuable to diagnose heart and blood disease in clinical diagnosis. It is approved that HRV signal possess non-linear characteristic, and we can analyse and present HRV signal with non-linear dynamic parameteres, such as fractal dimension. Based on phase-space reconstruction theory, an improved algorithm is introduced to calculate the correlation dimension of HRV signal, and some valuable conclusions are expressed according to the result which is concluded from the correlation dimension of nearly 30 samples. 相似文献
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山羊心脏型脂肪酸结合蛋白cDNA序列克隆及生物信息学分析 总被引：2，自引：1，他引：2
本文通过RT-PCR技术克隆山羊心脏型脂肪酸结合蛋白的cDNA 全序列,并对cDNA序列的氨基酸同源性、理化性质、二级结构特征进行了预测和分析。结果显示,山羊H-FABP基因cDNA全长402 bp,推测的氨基酸序列与绵头同源性为100%;H-FABP蛋白属疏水性蛋白,呈为弱酸性;二级结构以β折叠为主;不含跨膜结构域,具有潜在的信号肽位点、多个其它信号位点以及细胞脂肪酸结合信号位点,从而为揭示H-FABP蛋白空间结构和生物学功能研究提供理论基础。 相似文献
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The compositions of odor gases in Jizhuangzi sewage treatment plant of Tianjin in the summer of 2011 and 2012 were monitored by GC-MS. Meanwhile 24 subjects (11 male, 13 female) were selected for acute exposure experiment by HOLTER. 67 kinds of odors were detected out, the concentration of odor gases emitted from grid was the highest, sulfide and oxygen-contained were major species of odor gases; the acute exposure experiment at the grid showed that blood pressure reacted normal, maximum heart rate was significantly higher than normal value, mostly in the field test period, while the HRV parameters all deviated from normal range, which indicated that malodorous gases induced the subjects' sympathetic nerve activity. According to health risks assessment of odor gases from sewage treatment plan, methylene chloride and benzene of malodorous gases in the sludge dewatering had potential risk, non-carcinogenic hazard index (HI) was less than 1, within an acceptable range. 相似文献
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针对在主观偏好性试验中关门力度对听审者的主观评价有很大影响这一问题,考虑轻、重关门力度对声品质评价的影响,提出了一种新的关门声声品质评价参数——SE（sharpness-energy）。即利用二次EEMD分解和Wigner-Ville分布得到样本的能量分布,参考尖锐度计算公式推导得到SE计算公式,并将其归一化为百分制,SE突出了高频成分对声品质主观偏好性的影响。为验证参数SE的有效性,将该参数和主观评价结果进行相关性分析,结果表明当关门力度不同时,SE与样本评价结果相关性更高,SE比尖锐度能更准确地反映高频成分对声品质的影响。 相似文献
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The R-wave of ECG signal represents the electrical activation of the ventricles, which initiates ventricle contraction, and the typical peak value singular signal, so the R-wave of ECG signal is localized precisely and analyzed accurately using the wavelet transform. The principium of the precise detection method for R-wave in ECG signal is researched. The special properties of Mexican hat wavelet in time-domain are analyzed, too. This wavelet has every order continuity, symmetry, exponential attenuation and one vanishing moment. For this reason, the mexican hat wavelet basis has the excellent localization and analyzing precision. Using the MIT/BIH (Massachusetts Institute of Technology / Boston's Beth Israel Hospital) Arrhythmia Database and the applications in clinic, the precise detection method can detect accurately and localize precisely to the R-wave in ECG signal in the serious noise signal. This method has the quite high locating precision (its error is not more than one sampling point and the points of the R-wave in ECG signal about 80 percent are localized precisely) and analyzing accuracy (no accumulative error). The real-time of the method is excellent, and the real-time detection to the R-wave of ECG signal can achieve using this method. 相似文献
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Summary A factorial mating design with six 4x cultivars as stylar parents mated to three groups of pollen parents (4x cultivars, 4x high protein selections, and 2x S. phureja) was used to study breeding behavior of yield, tuber set, marketable yield and hollow heart in potatoes. Mean yield for the 4x-2x hybrids was equivalent to that of their cultivar parents although yield components, tuber set and average tuber size, were greater and less, respectively, than the cultivar parents. High estimates of general combining ability were found in both pollen and stylar parents for yield, tuber set, marketable yield, number of marketable tubers and hollow heart in all three hybrid populations. Specific combining ability estimates were significant only for yield and hollow heart. Frequency of white-fleshed 4x-2x progeny of five heterozygous yellow-fleshed 2x phureja genotypes was used to confirm cytological identification of a first division restitution mechanism operative in the 2x parents. Although three of these phureja genotypes generated high-yielding progeny, two others produced 4x-2x progeny with mean yield similar to that of hybrids among 4x cultivars.Scientific journal series article 11,601 of the Minnesota Agricultural Experiment Station. 相似文献
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Using studied ECG sampling system, the analog signals of electrocardiograph is magnified and filtered,sending into the sampling card in computer, the sampling frequence is 1 000 Hz, the 5 minutes sampling signal is saved to hard disk. Using modern spectrum analysis method and FFT, the specific value VLF/HF of Heart Rate Variability (HRV)of 19 healthy individuals and 10 hyperthyroid is analysed .It is found that the significant difference of the specific value VLF/HF between the healthy individuals and hyperthyroid.There are no especial advantage and distinctness by using the modern spectrum analysis method or FFT to study balance the specific value VLF/HF between the healthy individuals and hyperthyroid. The result shows that the spectrum analysis method is relly an effective measure to analyze independence nerve abnormalities of hyperthyroid. 相似文献
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草鱼MyoG基因的克隆及其组织表达谱分析 总被引：2，自引：1，他引：1
为了获得草鱼(Myogenin) MyoG基因序列,阐明其在草鱼不同组织的表达规律。根据鲤鱼(Cyprinus carpio)基因MyoG序列(AB012881)设计引物,通过RT-PCR技术克隆草鱼MyoG的cDNA全序列,并对cDNA序列的氨基酸同源性、理化性质等进行了预测和分析。同时利用半定量RT-PCR分析草鱼MyoG基因在草鱼不同组织中的mRNA表达特性。结果表明：得到草鱼MyoG序列789 bp,开放阅读框(ORF)序列762 bp, GenBank登陆号为JQ793897。编码253个氨基酸,具有MyoD家族基因的典型性碱性螺旋-环-螺旋(Basic helix-loop-helix,bHLH)结构,与斑马鱼、鲤鱼、虹鳟、大西洋鲑等同源性较高,为73%~95%,但与哺乳动物和禽类如人、小鼠、猪、牛和鸡的同源性较低,为53%~57%。在草鱼红肌、白肌、脂肪、肝胰脏、肾脏、脑、肠、心脏、鳃中均检测到MyoG基因的表达,并且在白肌中表达量显著高于其他组织(P＜0.05),在脑、肝胰脏和鳃中亦有较高水平表达。成功获得草鱼MyoG基因序列,并在白肌中的表达显著高于其他组织,为研究MyoG在草鱼肌肉发育过程中的作用提供基础资料。 相似文献