共查询到20条相似文献，搜索用时 31 毫秒
1.
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
2.
Wang Linyun Yin Xiaohui 《保鲜与加工》1990,(6):79-85
A method for coupled analysing plastic deformation of rolling workpiece and elastic de'formaticn of rolls is developed. The interaction of plastic defo rmation of rolling workpice and elastic deformation of rolls is considered. The couple is formulated by setting up force equilibrium equation at the interface of the rolling workpiece and tne rolls. The plastic deformation of rolling workpiece is treated by the rigid plastic finite element method and the elastic deformation of rolls is treated by the boundary element method. The rolling presure, perunit. forward slip, neutral from angle obtained from coupled analysis are lower than those obta-ined rigid rolls. The results obtained from analysis show that the analytical accuracy can be heightened using the coupled ana-ytical methcd dveeloped for treatng rolling3proccss. 相似文献
3.
Wang Jinhai Huang Zongming 《保鲜与加工》1989,(4)
This paper makes use of a beam-colunm model in the elastopl-astic dynamic analysis of RC planar rames.For which an improved method is presented to estabish the envelopes of moment-curvature relationships by appli-cation of RC nonlinear analysis,and a program named PFEPDA suitable to mic-rocomputer is developed. 相似文献
4.
The test and analysis results of model for the C6132 type lathe structure are introduced in this paper. Through recognizing the mode parameters and mode of vibration, the pernicious models are looked upon by the respond test analysis of random driver. The paper finally analysies the condition of the different order model frequencies in the vibration frequency spectrum for the tailstock and tool carrier during the different rotational speed. 相似文献
5.
The accuracy of modal parameters identification has the influence on the quality of dynamic characteristics analysis of mechanical structure directly. And the precision of the frequency response function estimation has the great influence on the accuracy of modal parameters identification. In the engineering the frequency response function can be estimated by the average power spectrum and cross-power spectrum with the hel Pof FFT. As the result of limited frequency resolution in the course of FFT and the noise, the accuracy of modal parameters identification is influenced by the frequency response function estimation. This paper has put forward a least-square-based optimization of frequency response function estimation in modal parameters identification. According to the optimized frequency response function, the peak value can be searched to identify the damped natural frequencies and damping ratio directly. An experiment has been made to validate the proposed method. The result indicates that the damped natural frequencies and damping ratio identified by the optimized frequency response function are closer to the true results than which without the optimized frequency response function. So the accuracy of modal parameters identification can be improved by adopting the proposed method. 相似文献
6.
Zhang Daijun Xian Xuefu Tan Xueshu 《保鲜与加工》1990,(1):78-84
In this paper, by Using Traube's Law, we presented a method with which the macromolecular structure of coal can be studied through the relation between the true density of coal and its chemical constitution Then we researched the
law of the variation of the macromolecular struclure of coal with its. rank. At the same time, we discuss the rank of coal which is classified in the constitution and macromolecular structure of coal 相似文献
7.
The frequency spectrum analyses of several vibration on No. 4 Unit in a power plant are made and the experience of the future failure diagnosis on turbogenerator is collected in this paper. 相似文献
8.
This paper deals on the method of ZOOM FFT based on analytic signal and band pass filter, which is different from other methods of ZOOM FFT. It is used on computer with larger zoom ratio; higher compute speed and so on than other ways for offline testing. It provides a new method for the development of Virtual Instruments on ZOOM FFT analysis. 相似文献
9.
In this paper, the dissolving condition of iron and vandium solidified in iron and the collecting method of the second phase vandium compounds in alloy steel are studied, the existing possibility of spreading phase vandium compounds in steel is discussed, which provide the possible conditions for concentration and electrochemical separation of the second phase vandium compounds. Using this method, quite reliable results in measuring vandium solidified in iron can be obtained. 相似文献
10.
根据湖南省多年多点的棉花苗情定点观察与气象观测资料,采用相关及多种回归分析方法,研究棉花产量与苗情性状及气候条件相互间的内在联系和定量关系,找出影响棉花生长发育及产量形成的主导因素,并根据所建立的回归方程进行苗情预测预报,从而提出有效的促控指标,为指挥棉花生产,作出宏观决策提供科学依据。 相似文献
11.
Lei Jiyao Zhang Sifu He Shide 《保鲜与加工》1988,(2)
This paper describes the research work of analyzing vibration signal to monitor and diagnose on line the ball bearing fatique. Carrying out a large mumber of life test on ball bearing test machine, it is discovered that in the so called "second effect" vibration signal as the bearing fatique occurs, apart from the two widely used spetrum charactersof "fraverse frequency" and "high frequency shock pulse" , there is another important but rarely known opcctrum characteristic of high frequency peaks existing in the middle-to-high frequency band.The generating mechanism, effect factors and test method of those high frequency peaks are researched tentativ tentatively. Two binds of device for monitoring abnd diagnos sing ball learing fatique on line are developed based ion this new type spectrum characteristic. One consists of a bandpass filter, the other is based on the spetrum characters which corns from the DDS ( Dynamic Data System ) modeling 相似文献
12.
In this paper,a computer program for nonlinear analysis ofa special frame is developed.The frame has all columns fixed at the base and hinged at the top.By taking the frame as a whole,the behavior ofthe frame is studied from the test results of three specimens of the frame andlarge amount of results of computer program.The minimun value of total sumof vertical loads sustained by the frame is found and a new method of deter-mining the effective length of stepped columns is suggested. 相似文献
13.
Skin electrode unit is a channel through which energy can be transferred to the implanted device by volume conduction. The unit can be equivalent to lumped circuit, but so far there are no appropriate calculation methods of these circuit parameters, so variable load method based on field-circuit coupled is proposed. A skin electrode unit field circuit coupled model is established to obtain the relationship of the network parameters between voltage and current at electrode port, and the amplitude and phase of the power signal is extracted by the use of all phase FFT spectrum analysis. On this basis, equivalent circuit impedance parameters of the skin electrode unit under various conditions are obtained by the application of variable load method and the validity of the method is verified. As a result, the equivalent circuit impedance parameters obtained in this way can be used for the circuit analysis and optimization of the volume conduction energy transfer system. 相似文献
14.
Chen Hua Zhou Jiaqi 《保鲜与加工》1989,(6):55-61
A new concept dafincd as k-weak minimal cut set, which, is used to characterize the weakness of the weak link set, is established in this paper. Based on this concept, a fast algcrithm or searching k-weak minimal cut set in large scale networks is proposed. From the analysis of computation complexity, it is shown that the frequency count of the algorithm is much lower and the algorithm is powerful to adequacy evaluation of the transmission capacity in large scale networks. 相似文献
15.
The determination of the structural plan of the main tall building of ChongqingJiangbei Commercial Center is introduced. In anti-seismic analysis,bend-torsion coupling vibrationis compared with plane vibration.Earthquake actions from any different directions for the structureare analysed also.The result of using direct dynamic analysis method is compared with that of usingSRSS method. 相似文献
16.
Virtual Instrument has become an important direction of instrument development, now it has been widely used in many fields. FFT analysis is a widely used method in mechanical engineering, fault detection and many other fields. However, the traditional FFT analyzer is expensive and is not easy to upgraded. The birth of virtual FFT Spectrum Analyzer gets rid of the limit of traditional FFT analyzer, and paves the way for the application of FFT analyzer. The uses of DSP technology make the future broadened of Virtual Instrument. This article ,based on the deep study of DSP system, designs a virtual FFT Spectrum analyzer based on DSP technology. The design is new and of great practicality, which indicates the important role of Virtual Instrument in the development of instruments. 相似文献
17.
Wang Yongyue 《保鲜与加工》1996,(1):27-31
The secant rigidity is used for the are-length method to solve the nonlinear finite elements problems. The advantage of this method is unnecessary of calculating the initial resistance term caused by the incremental step. The computational work is less and the programing is easier as compared with initial are-length method. This method can be widely used to solve nonlinear problems. 相似文献
18.
Li Longjian Zhang Hongji 《保鲜与加工》1991,(2):79-84
In this paper the heat transfer in the tube-mouth region of the high temperatur heat exchange equipment is deeply analysed. The effect; of the heat conducting cross-section area of the tube-mouth region and axial heat conduction along the tube on the temperature field is emphatically examined by numerical computation, and then the relation of the highest temperature in the tube with the elongated tube length is established. The computed results in this paper are compared with those without taking account of these two factors. It is shown that the effect can not be ignored for the corrosion-protection by controlling temperature. 相似文献
19.
通过光谱分析法定量测量了甘蓝型油菜(B.napus,L.)种子表面颜色的光度学和色度学指标,把甘蓝型油菜种皮颜色的变异分为8级,使相邻两级之间相差5个 NBS 色差单位。级别愈高,颜色愈深。通过相关和回归分析表明,在相同的遗传背景中,甘蓝型油菜种皮颜色与种籽含油量之间存在着显著负相关〔r=(-0.408)-(-0.662)〕。黄籽平 相似文献