基于多相滤波的正交器仿真分析     

陈义平 《鸡西大学学报》2004,4(3):83-85

基于多相滤波的正交处理器技术是软件无线电技术的重要组成部分。本文对基于多相滤波的正交处理器进行了详细的研究，并给出了在MATLAB环境下的仿真结果。  相似文献   

平滑Chahine迭代算法在光散射法粒度分布反演中的应用     

邵阳  王清华 《南京晓庄学院学报》2008,(6)

光散射法粒度测试涉及到粒度反演技术.随着反演粒级数的增加,通常的粒度反演法将出现严重的振荡.文章将Chahine迭代算法与平滑滤波技术相结合解决了高反演粒级数下数值解的振荡,在不改变激光粒度仪的原有结构情况下,就可明显提高仪器的精度和分辨能力.  相似文献   

一种简单的图像脉冲噪声滤除方法     

陈月芬  洪丹丹 《台州学院学报》2008,30(6):25-28

针对传统的中值滤波法消除脉冲噪声时存在的缺陷,充分利用脉冲噪声的特征,提出了一种简单的噪声像素检测方法,在滤波处理前先检测像素是否被脉冲噪声污染,从而有选择地对噪声进行自适应中值滤波,该算法不仅能够有效滤除脉冲噪声,而且具有较少的计算量和较高的峰值信噪比。仿真结果证明了算法的有效性。  相似文献   

排球发球中侧旋球的理论与实效性研究     

唐金根 《洛阳师范学院学报》2008,27(5)

本文运用刚体转动定律及流体伯努利方程对排球发侧旋球的弧线飞行原理和侧旋速度对飞行轨迹以及着地点进行理论分析研究,结果表明击球点于球体重心右侧1/3处、击球挥臂出手方位面向球网方向右转30度,用中等力量击球实效性较高。  相似文献   

Three-dimensional tracking of GLUT4 vesicles in TIRF microscopy     

Xiang-ping Wu  Jie-yue Li  Ying-ke Xu  Ke-di Xu  Xiao-xiang Zheng 《浙江大学学报(A卷英文版)》2008,9(2):232-240

TIRF microscopy has provided a means to view mobile granules within 100 nm in size in two dimensions. However quantitative analysis of the position and motion of those granules requires an appropriate tracking method. In this paper, we present a new tracking algorithm combined with the unique features of TIRF. Firstly a fluorescence correction procedure was processed to solve the problem of fluorescence bleaching over time. Mobile granules were then segmented from a time-lapse image stack by an adaptive background subtraction method. Kalman filter was introduced to estimate and track the granules that allowed reducing searching range and hence greater reliability in tracking process. After the tracked granules were located in x-y plane, the z-position was indirectly inferred from the changes in their intensities. In the experiments the algorithm was applied in tracking GLUT4 vesicles in living adipose cells. The results indicate that the algorithm has achieved robust estimation and tracking of the vesicles in three dimensions.  相似文献   

Evaluation and application of an efficient plant DNA extraction protocol for laboratory and field testing     

Qi WANG  Xiaoxia SHEN  Tian QIU  Wei WU  Lin LI  Zhi'an WANG  Huixia SHOU 《Journal of Zhejiang University. Science. B》2021,22(2):99

Nucleic acids in plant tissue lysates can be captured quickly by a cellulose filter paper and prepared for amplification after a quick purification.In this study,a published filter paper strip method was modified by sticking the filter paper on a polyvinyl chloride resin(PVC)sheet.This modified method is named EZ-D,for EASY DNA extraction.Compared with the original cetyl trimethylammonium bromide(CTAB)method,DNA extracted by EZ-D is more efficient in polymerase chain reaction(PCR)amplification due to the more stable performance of the EZ-D stick.The EZ-D method is also faster,easier,and cheaper.PCR analyses showed that DNA extracted from several types of plant tissues by EZ-D was appropriate for specific identification of biological samples.A regular PCR reaction can detect the EZ-D-extracted DNA template at concentration as low as 0.1 ng/μL.Evaluation of the EZ-D showed that DNA extracts could be successfully amplified by PCR reaction for DNA fragments up to 3000 bp in length and up to 80%in GC content.EZ-D was successfully used for DNA extraction from a variety of plant species and plant tissues.Moreover,when EZ-D was combined with the loop-mediated isothermal amplification(LAMP)method,DNA identification of biological samples could be achieved without the need for specialized equipment.As an optimized DNA purification method,EZ-D shows great advantages in application and can be used widely in laboratories where equipment is limited and rapid results are required.  相似文献   

河南农民收入增长的波动周期   总被引：6，自引：1，他引：5  

刘荣利 《四川教育学院学报》2008,24(11):37-39

河南农民人均收入时间序列,服从二阶单整过程,期间存在结构性断点,适合建立H—P滤波模型。自改革开放以来可划分为三个增长周期,其在不同的历史阶段具有明显不同的波动特征。  相似文献   

Snippets of physics     

T. Padmanabhan 《Resonance》2008,13(7):610-618

Thomas precession is a curious effect in special relativity which is purely kinematical in origin and illustrates some important features of the Lorentz transformation. It also has a beautiful geometric interpretation. We will explore these in this and the next installment. T Padmanabhan works at IUCAA, Pune and is interested in all areas of theoretical physics, especially those which have something to do with gravity.  相似文献   

宽阻带小型化低通滤波器的设计     

杨雪霞  薛玉杰 《上海大学学报(英文版)》2008,12(6):495-497

This paper presents a novel low-pass filter （LPF） with sharp rejection, wide stopband and compact size, which are realized by the defected ground structure （DGS） and the defected microstrip structure （DMS）. The equivalent circuit model is proposed and the circuit parameters are extracted by the circuit simulation software. The parameters measured are 3 dB cutoff frequency fc of 5.2 GHz, the insertion loss less than 0.5 dB from DC to 4.0 GHz and S21 less than -20 dB within the wide stopband from 6 GHz to 16 GHz. The results of the circuit optimization agree well with those of the full wave simulation and the measured ones, which validate the effectiveness of the equivalent circuit model. The size of the proposed LPF is decreased compared with normal LPF. This LPF can be applied in rectennas to eliminate high order harmonics.  相似文献   

磁场作用下的磁性流体行波泵研究     

赵猛  胡建辉  徐永向  邹继斌  王黎钦 《大连大学学报》2008,29(3):108-111

磁场作用下的磁性流体行波泵研究是行波泵设计的基础。通过分析了行波磁场作用下的磁性流体的运动方程,从而进一步推导了行波磁场作用下的磁性流体的速度方程、旋转速度方程和单位时间内的流量方程,并通过实验进行了验证。研究表明：行波磁场作用下的磁性流体会产生流动现象;行波磁场作用下的磁性流体流量与磁极旋转的角度有直接关系,磁极旋转的角度越大,其流量也越多;行波磁场的强弱对磁性流体流量也会产生影响,磁场越强,其流量越大;行波磁场的频率只能影响磁性流体的流速,对流量不产生任何直接影响。  相似文献