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   

用改进式电流传送器实现二阶电流模式状态变量滤波器     

彭良玉  吴杰 《科技通报》1996,12(1):26-30

提出了用改进式电流传送器实现二阶电流模式状态变量滤波器新电路，并由此得到了高通、带通、低通滤波特性。计算机仿真结果表明理论分析是正确的，所提电路具有灵敏度甚低的特点。  相似文献   

论提高中文搜索引擎质量的途径   总被引：11，自引：0，他引：11  

焦微玲 《情报科学》2002,20(1):100-102

随着网络信息数量的迅猛增长，搜索引擎的网络导航作用日益增强，然而搜索引擎自身也存在“信息过载”、“信息超量”的现象，如何克服上述现象，向用户提供数量适宜、质量优良的信息是目前迫切需要解决的问题。本文立足于本文搜索引擎，在分析了我国搜索引擎的发展状况和存在的问题之后，简单论述了可以提高中文搜索引擎质量的几条途径。  相似文献   

基于卡尔曼滤波的中国证券市场投资者情绪测度研究     

魏星集  夏维力  孙彤彤 《未来与发展》2016,(4):42-45

投资者情绪准确测度较为困难,因为其固有的动态复杂性和变化性。本研究通过对情绪测度理论方法进行系统分析,结合中国证券市场具体情境,基于卡尔曼滤波方法过滤掉市场噪声,选取封闭式基金折价率、新股上市首日收益率、新股发行数量、新增开户数四个指标,并通过滚动合成投资者情绪指数进而验证其有效性。  相似文献   

脉冲C类固态放大器中偏置馈电电路的研究   总被引：1，自引：0，他引：1  

张永慧 《中国科技信息》2006,(13):85-87

对脉冲C类固态放大器中偏置馈电电路部分作一些探讨，研究偏置馈电电路及其供电储能、滤波等，使放大器更稳定可靠地工作。  相似文献   

O-200kPa气动控制信号检测系统的设计     

黄爱芹 《滨州师专学报》2011,(6):91-94

为检测气动执行器常用控制信号0-200kPa气压,设计了基于MSP430单片机和压阻式压力传感器MPX2200的气压检测系统．阐述了检测系统的软硬件设计,给出了MPX2200恒流源电路和放大倍数可调的两级放大电路,介绍了软件设计中的标度变换、分段插值和中值滤波方法．该系统在电路设计上选用仪用放大器、单片机自带AD转换器,所用元器件少、功耗低、精度高,可广泛应用于智能化、低功耗化的气动执行机构及其元器件的设计中．  相似文献   

基于光电二极管的动脉血压信号无损监测技术     

熊元姣 《深圳职业技术学院学报》2015,(1):23-26

用红外发光二极管和光电二极管组成的光耦合指套,放置在人身体的指尖部位,通过检测人体末梢组织在动脉舒张和收缩时对红外光的吸收度变化率,来检测人体动脉血压信号的异常.红外发射二极管的驱动采用PWM信号调制的恒流驱动,光电二极管接收穿透人体后的红外光并转换成微弱的电信号,再经过前置放大、倒相、压控二阶低通滤波、陷波电路、A/D转换等处理后,MCU从采集的数据中提取有关动脉血压信号的特征值,实现血压信号异常的无损连续监测.  相似文献   

一种基于Kalman滤波和能量原理的实时损伤识别方法(英文)     

Xing-huai HUANG  Shirley DYKE  Zhao-dong XU 《浙江大学学报(A卷英文版)》2015,(2):105-116

目的:建立一种损伤识别方法,能够实时地监测多自由度复杂结构中构件的损伤情况。方法:1.用能量原理对结构刚度进行解构,建立结构单元刚度和节点响应之间的关系;2.用Kalman滤波原理分析结构刚度的预测值和测量值,迅速对结构的刚度进行识别(图6–9);3.对每一步计算进行耗时监测,确保算法的实时性(图10)。结论:1.该方法能够较准确地得到结构的刚度信息,同时得出损伤单元的损伤位置和损伤量;并且收敛速度快,计算量小,具有很强的实时性和抗噪能力;2.对于本文的桁架结构,所有杆件刚度均能在0.4 s内收敛,平均每一荷载步计算时间约为0.0012 s,小于采样周期1/256 s,说明该方法可以迅速、准确地对结构进行实时的监测。  相似文献   

相位谱拟合车载自组网中功率增益优化方法     

金鑫 《科技通报》2015,(2):79-81

车载自组网WSN无线传感网络的接收/发射功率的无偏均衡设计,可以提高网络节点寿命,保证系统的稳定性,提高车载自组网的通信能力和网络连接率。传统方法采用的固定步长加权的滤波设计算法进行功率均衡设计,导致车载自组网的相邻节点功率均衡偏差,提出一种基于无偏均衡和相位谱拟合的车载自组网中功率增益优化算法,进行无偏均衡的车载自组网中网络连接率优化设计,确定节点一跳范围内的邻居节点,实现功率谱的估计,在功率均衡设计中,进行可变步长滤波设计,反映了信道幅值、时间和频率之间关系,对相位谱做最小二乘拟合求斜率,实现WSN可变步长滤波接收/发射功率无偏均衡算法改进。研究结果表明,该算法实现了接收/发射功率的无偏均衡,网传输距离提高,具有较大的功率增益,网络连接率较传统方法提高,展示了优越的应用性能。  相似文献   

Engagement with news on Twitter: insights from Australia and Korea     

Robert Ackland  Mathieu O’Neil  Sora Park 《亚洲交流杂志》2019,29(3):235-251

ABSTRACT

This study examines the patterns of news engagement among news consumers with different political affiliation and cultural background. We use computational methods and data from Twitter in a cross-country comparison of engagement with six online news sources in Australia and South Korea. For our analysis, we used a subset of Twitter users who retweeted at least one political story during the period of collection, and for whom we were able to predict political affiliation using correspondence analysis and data on Twitter follower ties to politicians. We find that right-wing Australian retweeters are more intense in their news engagement, compared with their left-wing counterparts, whereas in South Korea it was the opposite. Australian right-wing political retweeters have more diverse information sources, while there was no difference in information diversity between the right and left in South Korea. We discuss how the political situation in South Korea at the time of data collection may have affected our analysis. We emphasise the methodological contributions of our research and its connection to on-going research into the behavioural foundations of ‘filter bubbles’.  相似文献