Application of Time-frequency Representations in Study on Heart Sound

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.     

Application of Electret Microphone in the Heart Sound Acquisition

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.     

Adaptive Enhancementt of Heart Sound Based on Simulink

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.     

Signal Processing Techniques for Radar Reconnaissance System Based on Time-frequency Analysis

The complex non-stationary signals are most often used in modem radar and communication systems. It must perform the tasks of envelope detection and intra-pulse feature analysis for radar pulse classification and identification. Time-frequency analysis is an effective tool for modem signal processing, and often applied to analyze and process non-stationary signals. Several methods of time-frequency analysis are presented, reconnaissance are also discussed and simulated. Simulation results show the and their applications in the radar signal effectiveness of these methods.     

Analyse of Compressor Sound Quality

By of Stevens steady wide frequency noise loudness and Fastl total sensation noise calculation method, sound quality evaluation of the noise left and back-end face was studied before the compressor improved and after the minipore muffler installed. The research indicates that the compressor noise is reduced, at the same time, the loudness left the compressor and the back - end face is reduced by 10.25 sone and 13.3 sone respectively. The rate reduced is over 40%. The total sensation noise is reduced by 12.5 noy and 15 noy, the rate achieved is over 45%. It is very perfect to improve the compressor sound quality with the use of minipore muffler.     

Application of Sound Intensity Technique to Measure the Noise of Electromotor

This paper has explained the characteristics,virtue of sound intensity measurement and the principle. And compare with traditional sound pressure measurement. The principle and composing of virtual sound intensity measurement system based on two-channel FFT analysis are researched. The sound power of large turbogeneratorin operating site is determined by means of sound intensity measurement and sound pressuremeasurement. Itis demonstrated that the method of sound intensity measurement of engine is practicable and the measuring data are valid and the method conquers the problems of traditional method of sound pressure measurement which is apt to environmentinfluence and sound power measurement need to especially acoustic environment. It is proved that the sound intensity method is especially suited to determine highaccuratelythe sound Power level of the electrical machines operating in situated conditions especially in case of acoustically worst environments or on loadand themethod is so superiorityin noise measurement.     

Time-frequency Characteristic of Wavelet Base and Its Application Transient Signal Detection

The application of wavelet analysis in fault diagnosis is growing rapidly.There are many different wavelet base to use but no accepted procedure for choosing among them, the analysis results by using them have great difference. This paper describes the significant properties of wavelet base, and analysis behavior of transient signal in wavelet transform, result on some methods for how to choose wavelet base in analysis transient signal.     

大灵猫、小灵猫的直针毛红外光谱比较研究

为了研究动物毛发的红外光谱学特征在动物分类中的应用。使用傅立叶红外光谱(FTIR)对大灵猫和小灵猫的毛发进行了检测和分析。结果表明：2种动物同一根直针毛从毛尖到毛根不同部位间红外图谱存在差异,说明毛发的不同部位都有受同一基因表达控制的角蛋白成份存在,但数量存在差异。2种动物直针毛中部的红外图谱具有明显的种间差异,主要表现在626~655 cm波数范围内大灵猫、小灵猫红外图谱在峰面积和峰值均有明显差异;大灵猫具有异构角蛋白构型,在640.3 cm和646.1 cm位置出现了N-H-基团的伸缩振动M形吸收峰。所以红外光谱是一种检测和分析动物毛发的有效的技术手段,在野生的动物的分类研究中有较好的应用前景。     

Biological Effect of Sound Field Stimulation on Baddy Rice Seeds

The authors adopt the apparatus for sound enhancing plant growth manufactured by themselves. The sound effect of Paddy Rice seeds is researched on the germination rate, germination index, height of stem, increase rate of fresh weight, rooting ability, activity of root system and the penetrability of cell membrane. The study not only validates that sound field stimulation can certainly promote the growth of plant, but also indicates the practicability of the apparatus.     

Correlation Dimension Analysis on Heart Rate Variability Signal

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.     

Brief Study on Physiological Effects of Sound Field on Actinidia Chinensis Callus

Insight into the relationship between plant cell (tissue) and physical stimulation is a focus of biomechanics. In this study, several important plant physiological indexes of Actinidia chinensis callus in sound field including the content of soluble proteins, the activity of SOD, the activity of IAA oxidase and the penetrability of cell membrane, were measured. Some information is got about stress effect through the study and try to explore its mechanism. From the result of experiment,we found that there were a great similarity of stress effect on sound field between Actinidia chinensis and Gerbera Jamesonii acrocarpous , a kind of herbage plant, which had been studied in our lab before. That is to say, the sound field also has dual effect on woody plant. It can enhance or inhibit the growth and development of Actinidia chinensis callus along with the sound field frequency ,and the moderate frequency of sound field acting on the callus could promote callus growth. A conclusion is drawn that the optimal stimulation of sound field are 100 dB and 1 000 Hz. Under the conditions, the sound field can distinctly enhance the growth of Actinidia chinensis callus Whereas, it is not very easy to explore the detail mechanism of environmental stress effects on plant. This paper discussed the mechanism of sound field stress on plant from the level of cell and molecule.     

Hyperthyroid Heart Rate Varialility Signal Using Modern Spectrum Analysis Method

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.     

Application of Sound Intensity Measurement Method in Spotting the Noise Source of Engine Surface

During the study of noise emitted by accelerating mini-vehicle control, using theory of sound intensity measurement, it is actualized spotting the noise sources with the mini-vehicle engine. In the procees of the contour of sound intensity and frequency spectrum analysis, main noises of the engine are from oil sump tank and delivery menifold shield and two-way branch exhaust pipe shield. These noises are produced from the engine combustion. According to all analysis, the authors bring forward methods of modifying structure of shield-shell parts and consider them as main methods of reducing noises.     

Intelligent Sound Broadcast System of Bus Based on CPLD

The traditional sound broadcast system of bus makes use of MPU. It's shortcoming is have lower dependability, at the same time the maintenance and upgrade is difficult. In order to solve these problems, an intelligent sound broadcast system of bus makes use of Complex Programmable Logic Device(CPLD) and sound chip ISD2560 is introduced, and the principle of design is analysed. Because of the ability of In System Programmability of CPLD's JTAG, and take full advantage of the resource in CPLD, this system have no use for MPU. So, the hard circuit of this system is simple, and the system is easy to debug, upgrade and has very high dependability and better practicability.     

Filtering Method for the Decomposition of Heart Rate Variability Power Spectral

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.     

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

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。