共查询到20条相似文献，搜索用时 31 毫秒
1.
After investigating into the design of classical FIR digital filter, a method of FIR filter design based on proximate best uniform approximation is proposed. The paper introduces the theoretical basis of the proximate best uniform approximation theory in detail, and applies it to the design of FIR digital filter. The procedure of designing a FIR filter with the proximate best uniform approximation method is given. The example shows that the filter designed by this method is of good performance in both pass band and eliminated band, and comparatively little calculation related, and hence it is of promising prospect to be applied. 相似文献
2.
Based on the measured data from the construction site, the prediction uncertainty of the CEB FIP MC90 due to the variation of the calculation parameters (i.e. the external uncertainty) and their sensitivity are analyzed with the help of statistical method and Latin Hypercube sampling method. Three conclusions can be deduced from the analysis. Those are a)the external uncertainty and its decreasing rate of the CEB FIP MC90 reduce with the time increasing, b)the creep coefficient increases with the increasing temperature while decreases with the increase of other calculation parameters, c)in accordance with the degrees of effect to the creep uncertainty, the first three calculation parameters are relative humidity, loading age and temperature, if the variation of the loading age is not taken into acount, the uncertainty of the creep pridection will be underestimated. Also, a method to analyze the uncertainty of the bridge structure due to the creep prediction uncertainty is proposed after the creep uncertain factor, which is the standard of the uncertainty of the creep, is introduced. An exmaple is analyzed in this paper using the random sampling method and the method presented in this paper. Through drawing a comparison between the results from different methods, the method presented in this paper appears to be feasible and efficient. 相似文献
3.
根据GB 4789.35—2010乳酸菌检验的方法对酸乳样品进行计数时,得出的数据容易出现偏差。经过一系列的试验、分析和研究,结果表明,在MRS培养基上由于乳杆菌生长形态不同于其他乳酸菌,可单独对乳杆菌进行计数;而嗜热链球菌和乳杆菌在MC培养基上难以辨别,两者可共同计数;双歧杆菌在TOS培养基的生长状态优于其他培养基,所以TOS培养基可作为双歧杆菌的计数培养基。MC和TOS培养基数据之和,即可得出乳酸菌总数。 相似文献
4.
The gas-solid two-phase flow characteristics of fine particles in the filter media were simulated based on CFD-DEM (Discrete Element Method) in this study, and the particle group, particle size distribution, and the rebound effect between particles, particle and fiber were taken into account the calculations. Additionally, the movement characteristics of the particle group and the deposition form of the fine particles in the fibrous filtration were analyzed. The results indicate that it is convenient and feasible to simulate the filtration process of the filter media as well as the deposition process and form of the fine particle on the media surface using CFD-DEM, and the simulation results are consistent with the experimental observations in the literature. The surface filtration has larger contribution to the filtration process, and most of the particles are captured by the media surface. Meanwhile, parts of smaller particles that enter into the media are captured by the depth filtration. A larger number of particles are collected by the particle-particle capture mechanism. The filtration efficiencies of the filter media are varied with the particle systems, and for the model of the filter media in this study, the filtration efficiency of the multi-particle system is about 20% higher than that of the single-particle one. 相似文献
5.
The archtecture and characteristic of digital matched filter circuit used for PN code synchronization are introduced and the method of PN code serial search acquition based on DMF has been researched in AWGN channel.Furthermore the detection probability and false alarm probability are derived for different correlation time(partitive period or whole period).Finally,the results of calculation and emulation are given in order to be employed as useful theoretical bases for reserching the acquisition performance of digital matched filter. 相似文献
6.
7.
Zhong Jingxiao 《保鲜与加工》1989,(4)
This paper introduces the metod of optimal design of municipal water distribution,The main points are the theory,mathematical model,program frame figure and example in practice of the optimal method of hydraulics.The
program is applicable to the design and calculation of the pipe network in a city. It gives a simple and convenient calculation method for multiple-scheme design and scheme cmparison of water supply system. 相似文献
8.
The article focuses on the method of noise cancellation for EEG signal. The method of notch filter is discussed. According to the frequency of noise and the principle of notch filter, the design result of the notch filter and the denoised signal are presented. Then, the analysis of EEG signal are proposed based on wavelet transform (WT) and noise cancellation using WT. Wavelet transform is a multi-resolution time-frequency analysis method. It can decompose mixed signal into signals at different frequency bands. The EEG signal is analyzed and denoised using WT, then the results are presented respectively. Comparing the experiment results shows that WT can detect and process noise in the EEG signal effectively. 相似文献
9.
In this paper,the approximation calculation method based on calculation model of earthwork formula of tetragonal prism is described. The optimization design elevation in large earthwork can be determined by this method. Through introducing a set of different design elevations, the difference between and sum of the total excavation and the total fill can be calculated. An economical analysis is carried out on the design elevation chosen with little value for both cases by numerical values comparison. The elevation with the lowest cost is taken as the optimal design elevation. 相似文献
10.
Hydraulic system pressure, contact surface between grinding roller and materials and grinding roller force of roller mill are analyzed. A new roller pressure calculation method named average surface roller pressure calculation method is proposed,and the corresponding theoretical formula is derived from three different perspectives, including roller pressure numerical calculation, stress and strain of main components and mill power through the calculation of real samples. The average surface roller and traditional average material roller pressure are compared to verify the correctness and accuracy of the proposed method. Design parameters such as the grinding roller structure, material maximum size, layer height and working pressure of the hydraulic system on the influence of roller are analyzed according to the formula of roller pressure. The research results provide theoretical basis for the selection of design parameters and the design calculation of structural strength for roller mill. 相似文献
11.
A new kind of filter media, zeolite, is used to enhance filtration for an improvement on tap water quality. The experimental results show that zeolite can remove not only turbidity but also ammonia-N and partial organic pollutants in water. In the experments, zeolite can remove about 65% of turbidity and over 10% of COD Mn , 95% of ammonia-N from water, the removal efficiencies of anianon detergent(LAS), chloroform and phenol are over 17.7%, 44.45% and 34% respectively, and metal ion contamination has not been found in filter effluence. Therefore, zeolite enhanced filtration is an efficiency and security method for an improvement on water quality. 相似文献
12.
为了研究4个与采食量相关功能基因可能存在的互作关系,采用基因重组的方法构建了黑素皮质激素受体-4(MC4R)基因的真核表达载体,采用脂质体法将该表达载体转染入成纤维细胞,瞬时转染24 h后,采用Real-timePCR的方法检测和分析了Leptin、黑素皮质激素受体-3(MC3R)和猪缩胆囊素受体(CCKAR)基因mRNA的表达变化情况。结果表明,在成纤维细胞中,过表达MC4R基因后,Leptin、MC3R和CCKAR基因的mRNA水平均无显著变化。据此推测,MC4R基因与其他3个基因虽都参与调节动物的采食量,但很可能是通过不同的调控路径来发挥功能的。 相似文献
13.
Multirate filter banks and wavelet transform are closely related theoretically and practically. This paper researches the wavelet transform of discrete-time sequences basing on dendriform filer banks in the signal processing field, analyses the theory and design method of two channel conjugate quadrature mirror filter banks and fast implement of discrete orthogonal wavelet transform and generation of orthogonal wavelets, and points out the internal relationship between them. 相似文献
14.
为减小平板型空滤器流动阻力以增大进气量,对平板型空滤器流动阻力特性开展了实验研究,获得了空滤器流动阻力随流量变化的规律和阻力构成成分。阻力随流量的增大而加速增大,滤芯阻力约占整个空滤器阻力的一半,入口流量为120 m 3/h时,总阻力为915.3 Pa,滤芯阻力为426.4 Pa。在实验获得滤芯阻力参数的基础上,提出采用多孔介质跃升模型对平板型空滤器内部流场开展三维数值仿真分析,结果表明,仿真结果与实验结果比较吻合,最大误差为5.67%。滤芯阻力同样约占整个阻力的一半,另一半阻力主要为出口处阻力,其余壁面阻力约占15%。最后,在实验和仿真分析的基础上,提出了改进模型并进行了仿真分析。结果表明,改进模型阻力有较大程度的下降,入口流量为120 m 3/h时,总阻力为588.2 Pa,较原始模型下降了32.2%;增大空滤器流通横截面积是减小阻力以增大进气量的有效手段,改进空滤器壁面的平滑性是补充措施。 相似文献
15.
The filter design is the key to 2-D image wavelet transform. Based on the studying of image properties and 1-D wavelet theory,the authors describe a parasymmetry boundary extension method and realize 2-D discrete wavelet transform by means of 1-D wavelet transform according to correlation of adjacent pixels. Also,it is proved that the discrete wavelet transform of inverse data stream in row and the sign of discrete detail signal will be inversed,and that a filter of wavelet transform based on symmetry of bi_orthogonal filter is constructed. The test has proved the fine reconstruction and perfect SNR. 相似文献
16.
A new efficient method named matrix method is presented based on the traditional calculation methods of stabilizing force. The method is derived from the thrust force method and designed to address the deficiency of traditional method. It cannot only get the best pile location with minimum stabilizing force when is applied to the design calculation of single row anti slide piles, but also be applied to the optimal calculation of multi row anti slide piles. The cases comparing results show the method is more reasonable. For major projects of landslide control, the combination of matrix method and finite element method can make the result safer and more accurate. 相似文献
17.
以大豆原油为原料,分别选择硅藻土、活性炭、活性白土、豆粕、珍珠岩、木质纤维素、凹凸棒土和膨润土作为过滤介质,对大豆原油过滤除杂,制备大豆浓缩磷脂,研究各种过滤介质对大豆浓缩磷脂透明度的影响,结果表明木质纤维素可以有效去除大豆原油中的杂质,制备得到的大豆浓缩磷脂透明度甚至比食品级大豆浓缩磷脂高。 相似文献
18.
In order to improve the system effect, it is necessary take the technique of digital signal process to suppress interference, because of the finite gain and the narrow-band interference in system of direct sequence spread spectrum. The authors design a new filter structure improving on tunable digital heterodyne adaptive notch filters. This filter can adaptively track the interference frequency and control the bandwidth and depth of notch, which has the excellent agility and utility. The experiment proves this method overcomes limitation of other interference suppressions, hardly weaken the system performances, enhances the stability of the filter system, and can quickly track the interference frequency. 相似文献
19.
汽车转弯自动照明控制系统数据采集滤波方法 总被引：1，自引：0，他引：1
为了减少汽车转弯自动照明控制系统数据滤波处理中的延时,在滑动中值滤波方法基础上,提出了一种带补偿的限幅滑动中值滤波算法,通过补偿的方式跟随信号的变化趋势。该算法通过2个步骤完成滤波,先对数据进行带补偿方式的限幅处理,再进行滑动中值滤波处理。该算法综合了滑动中值滤波法的实时性以及限幅滤波法对偶然性干扰滤除的有效性,实现更准确的滤波。仿真与实测结果表明,与滑动中值滤波方法相比较,改进后的算法滤波能够实时地滤除数据中的干扰,处理时间可减少62%,滤波效果较好,且速度信号的数据滞后时间较短,实时性较高,满足系统设计要求。 相似文献
20.
FU Bin ZHANG Qin CHENG Jian_ling ZHANG Jian_gao 《保鲜与加工》1999,(4):61-64
According to the features of CAD for building water supply and drainage design,the interactive method for CAD calculation and drawing in building water supply and drainage engineering are discussed . A practical example of ADS for hydraulic calculation has been given in this paper . 相似文献