叠加电桥检测的加速度传感器设计

基于压阻效应的叠加电桥检测法加速度传感器采用超对称"八悬臂梁—质量块"结构,构成惠斯通电桥的力敏电阻器布放在悬臂梁的两端,4个惠斯通电桥的输出电压叠加后作为传感器的最终输出,有效提高了加速度传感器的灵敏度。通过数学建模仿真分析验证了方案的可行性。性能测试结果表明:该加速度计的灵敏度为1.1381mV/gn,频响范围为0～1000Hz,灵敏度约为单电桥检测法和串联电桥检测法加速度传感器灵敏度的4倍。叠加电桥检测法为压阻式传感器提高灵敏度提供了一种新思路。     

探究板式惠斯通电桥灵敏度的影响因素

改变板式惠斯通电桥实验电路的部分结构，详细推导惠斯通电桥灵敏度公式，分析电桥灵敏度的影响因素，同时利用交换法合理调节电桥灵敏度的影响参量，可以测量未知电阻，且测量结果更加精确，有助于对板式惠斯通电桥实验原理的进一步理解。     

P+N+器件压磁电效应的研究

用载流子连续方程研究了一个侧面设置坑复合区的双注入Ｐ＾＋πＮ＾＋器件的压磁电效应，给出了伏安特性与压力和磁场强度的函数关系，结果表明，当四个Ｐ＾＋πＮ＾＋器件在“基区”两两垂直组成惠斯登电桥，制造在Ｃ型硅杯的硅膜片上，不但具有较高的压力灵敏度和磁灵敏度，而且可以用来测量磁场的旋转角度。     

探伤仪桥路设计及仿真分析

电桥的设计是研制涡流检测仪的关键,它影响整个检测系统的灵敏性、可靠性和稳定性。针对常用电桥的输出值很小,放大困难的情况,设计了新的电桥电路,提高了桥路输出值,使得放大以及后级处理容易实现。通过仿真分析,得出辅助桥臂对桥路的灵敏度和输出值的影响,为不同要求下辅助桥臂的选择提供了思路和依据。     

基于巨磁电阻传感器的磁珠检测方法

根据多层膜巨磁电阻(GMR)传感器检测速度快、灵敏度高、仪器易于小型化的特点,比较了不同磁场激励方式与输出信号处理方法,采用电桥电压与激励磁场双调制的检测方法,提高了传感器的信噪比,实现了微米磁珠的定量检测和纳米磁珠的定性检测.     

应变计的机械热噪声及噪声抑制

应变式传感器的机械热噪声是由于其应变栅与环境相互作用而产生的随机噪声,它影响传感器的灵敏度和分辨力,并增加测量随机误差,制约着应变式传感器的应用。分析导出应变式传感器机械热噪声的一般形式,并用虚拟仪器技术的软件滤波及归一化处理等方法有效地抑制了噪声,使应变式传感器测试系统的准确度提高了一个数量级,说明虚拟仪器技术的软件滤波及归一化处理是抑制噪声的有效方法。     

恒压供电单桥恒温式燃气检测电路“双桥恒温式燃气检测方法”补述

“双桥恒温式燃气检测方法”^[1]文,声称“恒温方式检测燃气量电桥,不宜采用传统恒压供电的单桥电路”之说,不够全面。特提出“恒压电单桥电路”,予以补充,以求得对电桥电路对称性有一完整的概念。     

用自平衡电桥法补偿压力传感器灵敏度温漂

本文就压力传感器的灵敏度温漂问题进行评述,分析了灵敏度产生的原因并提出利用自平衡电桥法解决灵敏度湿漂的补偿方法。     

基于μPSD3200的甲烷检测仪的研究与实现

论述了热载体催化元件检测法的原理,提出了对电桥电源和电桥输出电压同步测量的改进方案,有效地提高了测量精度。应用μPSD3200的CPLD功能,实现了软硬件结合的SPI接口方法,提高了MCU运行效率。提出了矿井“黑匣子”,给出了一种硬件控制的安全存取数据的方法,增强了仪表的抗干扰能力。     

测量电桥的电压灵敏度和非线性误差

在电量测量中,按"偏转法"原理工作的不平衡式电桥,桥路对角线(负载端)有信号电压输出,因而去掉了平衡电桥的调零环节,从而改进了后续电路,动态性能良好,既可用于静态测量,也适用于动态测量。本文则着重讨论了不平衡式测量电桥的电压灵敏度和非线性误差。     

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.     

变电站一次设备喷涂PRTV用量的分析

对国网宁夏电力检修公司宁安运维站近2年来一次设备喷涂PRTV用量的统计数据进行分析整理,得出各类一次设备按照标准要求喷涂PRTV时的用量估算值,并针对现存作业中存在的问题,提出相应解决方案。     

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.