基于振弦传感器功率测量仪的设计与仿真

本文首先介绍了振弦传感器的工作原理,在此基础上阐述了基于振弦传感器的功率测量仪的原理并给出了相关电路的设计,最后采用Proteus软件列功率测量仪中的关键电路进行了仿真,验证了设计的可行性。     

多路振弦传感器的扫频激振技术

一种基于单片机比较模式的扫频激振技术实现的多路振弦传感器分时激振的新方法。与传统的激振方法相比,具有硬件电路简单、激振效果好、扫频信号频率可控等优点。固态继电器和恒流弱激振电路的应用,减小了电路的电磁辐射,避免了振弦的倍频振动,提高了振弦传感器振动的稳定性和一致性。     

单线圈光电式振弦传感器测频系统的设计

在对振弦传感器的特性和工程应用进行研究的基础上,创新的设计了一种单线圈光电式振弦传感器,同时给出了相应的激振、拾振和测频系统的设计。振弦传感器采用单线圈电磁激振方式,应用光电管结合MCU进行振动信号反馈,不但简化了硬件电路,而且解除了激振和拾振中电磁干扰问题,提高了测量的精度和稳定性。激振中采用的扫频技术也使振弦的起振更加稳定可靠。     

振弦式传感器激振策略优化

振弦式传感器的激励常用高压拨弦激振和低压扫频激振两种方式。高压拨弦激振对传感器损伤较大,信号衰减快,测量精度差;低压扫频激振扫描时间长,信号不宜拾取。提出一种反馈式低压激振方法,降低拨弦激振电压对传感器进行预激振,将反馈的振动频率信号作为输出,对传感器进行复振,可以在很短时间内使振弦达到共振状态。设计专用检测电路对调优后的激振策略进行验证,证明该方法激振时间短,共振幅度大。振动幅度的提高可增强抗干扰能力、降低信号处理电路成本、增加可用测量时间、提高频率测量精度。     

一种基于振弦式传感器测频方法的实现

设计了一种基于振弦式传感器的测频方法,介绍了振弦式传感器的工作原理,详细介绍了测频方法的设计思想、硬件电路组成和工作原理及软件设计流程。实验表明:利用本方法测量频率的分辨力为0.01Hz,与XPO2型频率测定仪测量的差值均在2Hz以内。具有设计思路清楚、硬件电路简单、激振可靠、激振频率可控、信号灵敏度高、操作简单、数值显示、价格低廉、连续快速检测等特点,具有较好的应用前景。     

振弦式传感器扫频激振技术

介绍一种基于ICL8038的扫频激振技术实现激振单线圈振弦式传感器的新方法，它与传统的激振方法相比，具有硬件电路简单、激振效果好、速度快、可控性好等优点。     

谐振敏感元件特性模拟器的研究

为了实现谐振式硅微传感器测试仪器的直接校验,以及进行谐振式传感器反馈控制电路的优化研究,设计了能够模拟压阻拾振式谐振敏感元件特性的电路.其中压阻变换是该电路实现的关键.文章采用模拟电路实现对谐振敏感元件的电阻拾振特性的模拟,得到受电压线性控制的交变电阻.对该电路进行了高频特性分析,提出一种可拓宽其频带的反馈补偿技术,从...     

一种差动电容式加速度传感器设计的理论研究

设计了一种差动式测振传感器,建立了差动电容式加速度传感器的数学模型,并通过电容的推导计算对其进行了特性分析。对检测电路的结构进行了分析,给出了典型电路结构,推到了电路参数及性能;本设计具有电路结构简单,频率范围宽约0～500Hz,线性度小于1%,灵敏度高,输出稳定,测量误差小等优点;通过实验,各项性能指标满足设计要求。     

一种基于锁相技术的冰传感器电路设计

谐振频率的稳定性是结冰信号传感器实现高准确度测量的关键技术。针对振管振动频率的稳定性问题 ,设计了一种基于锁相环技术的自激式的激励和检测电路。实验表明 ,该电路可以满足结冰信号传感器对频率测量的要求     

桥梁无线传感系统设计与分析

为满足桥梁监测的要求,对采集的数据实现无线传输,设计了数据无线采集传输系统.以STM微处理器和振弦式传感器为核心元件,对桥梁应变进行监测分析.分析了振弦式传感器的工作原理,对比分析了两种传统的激振原理,并结合两种激振方式的优缺点,提出了对低压扫频激振原理的改进方法,对激振电路进行了优化设计,同时设计了基于NRF905无线传感网络,完成了数据采集的无线发送和接收.实验结果表明:改进后的激振电路测量精度小于0.1％,系统工作稳定,无线传输功能满足桥梁监测要求.     

Effective solution of certain problems of theory of schedulings of nets

Cybernetics and Systems Analysis -     

Complexity of families of learning algorithms and estimation of the nonrandomness of extraction of empirical regularities

The paper presents a general approach to the evaluation of the complexity of classes of algorithms, so-called pVCD-method. To develop this method, all the examined families of models of empiric generalization were restricted to classes implementable on computers and, wider, by examining their partially recursive representations. Within the framework of the algorithmic approach, the concept of Kolmogorov’ complexity of algorithms for the recognition of properties or the extraction of regularities is proposed. The method proposed to evaluate the nonrandomness of the extraction of empirical regularities is based on this concept.     

Analysis of microdensitometric data in terms of probability of cleavage of DNA

Computer-aided analysis of autoradiographic films of DNA fragments is presented. The Powell least-squares procedure is used for optimization of parameters for components of complex densitometric curves. Since each densitometric spectrum may be divided for several non-overlapped blocks of bands, there is no upper limit on the number of parameters which must be optimized. Eight shapes for the component bands are utilized: symmetric and asymmetric Gauss and Cauchy functions, direct, symmetric and asymmetric product of Gauss function and inverse of Cauchy function, and log-normal function. The probability of DNA cleavage is calculated with correction for multiple cuts. The methods presented was applied to detailed analysis of densitometric spectra of a 21-bp DNA restriction fragment and allowed for direct correlation between structural microheterogeneity of DNA and the resulting cutting pattern. This method should facilitate the analysis of densitometric data from antibiotic-induced cleavage of DNA and footprinting experiments.     

联合收割机脱粒滚筒恒速智能控制器设计

研究了轴流式联合收割机的控制问题,给出了联合收割机脱粒滚筒的数学模型,介绍了基于模式识别的智能控制原理,建立了联合收割机脱粒滚筒恒速控制模型,设计了基于模式识别的智能恒速控制器.应用Matlab/Simulink进行了控制器仿真,其结果表明,将基于模式识别的智能控制应用于联合收割机脱粒滚筒的恒速控制,其过渡过程平稳、响应速度快、无超调、无振荡并且无稳态误差.     

An estimate of numbers of terms of semicycles of delay difference equations

In this paper, we study the semicycles of oscillatory solutions of the delay difference equation y_n+1 − y_n + p_ny_n-k = 0, where p_n is a sequence of nonnegative real numbers and k is a positive integer. Upper bound of numbers of terms of semicycles are determined in the case when

Our results improve and complement known results in literature.     

Complexity of approximation of 3-edge-coloring of graphs

The problem to find a 4-edge-coloring of a 3-regular graph is solvable in polynomial time but an analogous problem for 3-edge-coloring is NP-hard. To make the gap more precise, we study complexity of approximation algorithms for invariants measuring how far is a 3-regular graph from having a 3-edge-coloring. We show that it is an NP-hard problem to approximate such invariants with an error O(n1−ε), where n denotes the order of the graph and 0<ε<1 is a constant.     

Modifications of the method of variation of parameters

In spite of being a classical method for solving differential equations, the method of variation of parameters continues having a great interest in theoretical and practical applications, as in astrodynamics. In this paper we analyse this method providing some modifications and generalised theoretical results. Finally, we present an application to the determination of the ephemeris of an artificial satellite, showing the benefits of the method of variation of parameters for this kind of problems.     

计算机辅助课表编排技术的研究

讨论了几种实用的计算机辅助课表编排技术及在实际编排中的应用。应用分析表明，采用分批与或图搜索和分批优化的匈牙利算法相结合的方法，在计算机辅助课表编排中是行之有效的。