基于无线传感器网络的粮虫声信号采集系统设计

为了解决现有储粮害虫声信号采集系统存在的扩展性差、智能化程度不高、性价比较低、灵活性不强、数据传输能力较弱等问题,该文分析了现有储粮害虫声信号采集系统存在的局限性,在此基础上,利用无线传感器网络和压缩感知技术,设计了一种新型储粮害虫声信号采集系统,给出了系统结构和软硬件实现方法,并将其用于采集储粮罐内赤拟谷盗成虫的爬行声。试验结果表明,系统设计方案合理可行,且由于使用了压缩感知技术,在采样频率为10 KHz的情况下,可实现20个采集节点所产生的声信号原始采样数据的远程、实时、可靠无线传输。该研究为无线传感器网络在储粮害虫防治中的应用做出了探索。     

基于神经网络预测的无线传感器网络田间射频信号路径损耗

为解决应用无线传感器网络技术监测农田信息时无法快速预测射频信号路径损耗的问题,基于神经网络理论研究了田间路径损耗与其影响因素间的关系。试验中选取915和2 470 MHz 2个载波频率,在冬小麦的不同生长阶段测量射频信号在田间各影响因素作用下的路径损耗,建立和验证基于神经网络的射频信号田间路径损耗预测模型。所建立模型模拟值与实测值的相关系数为0.92,应用建立的神经网络预测田间射频信号路径损耗并与实测值对比,最大预测误差绝对值为4.186 dB,最大预测标准差为2.759 dB,预测准确度为94.2%。所建立的BP网络可以对田间射频信号路径损耗进行预测。     

钙调磷酸酶-活化T细胞核因子信号途径在骨骼肌细胞生长和发育中生理作用的研究进展

钙调磷酸酶-活化T细胞核因子(nuclear factor of activated T cells,NFAT)信号途径作为肌肉细胞内重要的生物信号转导途径,在肌肉细胞中起到调节枢纽的作用,与肌肉生长及肌纤维的类型有密切关系.而肌肉组织降解在动物肌肉嫩化过程中具有重要的意义.因此,钙调磷酸酶-NFAT信号途径可能与肌肉...     

Notch信号通路在体外培养的鹿茸干细胞中的表达

Notch信号通路是一条进化上十分保守的信号转导系统,在调节干细胞增殖、分化和凋亡方面起到重要作用。研究表明,鹿生茸区骨膜和角柄骨膜分别含有鹿茸发生和再生的干细胞。应用RT-PCR的方法对离体培养生茸区骨膜和角柄骨膜细胞进行检测,得出Notch信号通路各信号因子在2种细胞中的表达情况。结果:Notch-1、Notch-2、Notch-4、Dll-4J、agged-1J、agged-2、Hes-1等信号因子在这2种干细胞中均有不同程度的表达,说明Notch信号通路可能参与了他们的增殖、分化的调控。     

红缘天牛越冬幼虫耐寒性研究

旨在探索红缘天牛越冬幼虫的耐寒性。采用热电偶法和昆虫生理生化的主要研究方法,测定越冬幼虫的过冷却点、冰点、含水率、脂肪含量、糖原含量和血淋巴中游离氨基酸种类及质量浓度,并分析上述指标变化与幼虫耐寒性的关系。结果表明:不同大小幼虫的过冷却点与冰点均无显著差异(P0.05);幼虫经5℃1d处理后,过冷却点升高,冰点降低,均呈现显著差异(P0.05);含水率由71.89%减至69.97%;血淋巴液中谷氨酸、缬氨酸、蛋氨酸、苯丙氨酸、赖氨酸、组氨酸、精氨酸和脯氨酸占总量的百分比均有所提高;脂肪和糖原含量变化差异不显著(P0.05)。研究结果说明:红缘天牛越冬幼虫具有较强的过冷却能力,通过调节血淋巴液中氨基酸质量浓度的变化抵御短时间低温环境变化,提高其对寒冷的适应能力。     

Application on Extracting Feature in State Monitoring and Fault Diagnosis

With the development and application of information and internet and virtual instrument technology ,the virtual globular company based on internet arises .To study remote state monitoring, remote fault detection and diagnosis about large scale, complicated and integrative equipment become very important. In the whole fault diagnosis system , the detecting ,data acquisition is original ,processing; transform and extracting features with the signal detected is a key factor. The theories and methods used in mechanical fault diagnosis is stated. The application of signal process and its feature extracting methods is introduced which are time domain, frequency domain and time frequency domain analysis, in state monitoring and fault diagnosis with its signal analysis. The processing method of random time variant special signal is given also.     

模拟数控铣床的改造

本文对数控模拟铣床的改造,进给机构用两个步进电动机做动力源,控制系统用8051单片机作为主控制器,用数字信息通过单片机传送给步进电动机控制其按一定方式运行,即可达到零件的加工要求。     

Alkali-extractable soil organic matter: An important factor affecting the mycelial growth of ectomycorrhizal fungi

Significant effects of two fractions of alkali-extractable soil organic matter (AEOM) extracted from three different soils (agricultural soil, soil from deciduous forest, soil from spruce monoculture) on mycelial growth of 17 isolates of ectomycorrhizal fungi were observed. Growth of Lactarius deterrimus, Meliniomyces bicolor and one of the isolates of Leccinum aurantiacum was significantly stimulated by acid-insoluble fraction extracted from all three soils. The stimulatory effects were frequent but inhibition of mycelial growth of some isolates was also observed. The fungal response to the presence of the organic extract in the nutrient medium was isolate-specific rather than species-specific. Organic matter extracted from different source soils affected differently the mycelial growth, the largest number of stimulatory effects being observed in an experiment where the extract was richest in trace elements Zn and Cu. At the same time, the observed stimulatory effects were not attributable to increased concentrations of trace elements in the nutrient medium. The results indicate that soil may be used as a source of extractable organic fractions which, when used as a cultivation medium additive, may significantly improve the growth of responsive fungal isolates. Under natural conditions, AEOM (traditionally designated humic substances) represent a potential factor affecting the composition of cenosis of ectomycorrhizal fungi in soil.     

监控系统图象信号传输线缆的选择

论述了监控系统图象信号传输中同轴电缆、双绞线和光纤的特点和传输特性，并对其技术性能进行了分析。     

梨幼果表皮果点形成的组织解剖观察

梨幼果期皮层细胞组织具有荧光物质,采用活组织切片和荧光显微观察的方法,研究了梨幼果表皮气孔转变为果点过程中,外部形态和内部细胞结构的变化,并根据皮孔细胞组织生长发育的特点,提出了栽培中减小果点形成的有效措施。