基于振弦传感器的应变无线测量系统设计

针对传统振弦式应变测量手段的缺点与不足,设计了一种基于振弦式传感器的应变无线测量系统。整个系统通过ARM来控制,并通过通用分组无线业务（ GPRS）网络组成无线通信网络,实现了完全无人值守测量和系统的远程控制以及数据的无线传输。系统采样太阳能供电,可以更好地适应现场和野外试验不方便布线和取电的场合;系统具有大容量数据存储能力,无线传输数据的能力,具有高可靠性、高精度、适应性强、低成本等诸多优点,该测量系统使用方便,功能强大,智能化,必将有良好的应用前景。     

南水北调箱涵混凝土施工工艺

阐述了南水北调箱涵施工工艺,该施工方法合理,速度快;模板费用比较经济,混凝土外观效果好;钢筋采用直螺纹连接,质量更有保证。对已完成的箱涵进行检测、评定,混凝土内实外光,无任何质量缺陷,质量优良。     

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。     

一种低复杂度振动信号检测分类算法

低复杂度的振动信号常规峰度检测算法只能检测人员入侵行为,不能检测车辆入侵行为.根据噪声数据与车辆入侵数据特点,结合时间窗和马尔柯夫过程概念,提出了基于改进峰度的振动信号检测分类算法.该算法引入背景噪声的平均能量,利用包含比例因子P和异常突变阈值r的分段函数代替信号能量,可以避免毛刺信号干扰,检测并区分人员入侵和车辆入侵而不需要任何先验条件.试验表明,该算法具有复杂度低,资源要求低,漏警率低的特点.     

双振动电机同步最优控制方法

应用最优控制理论,提出新的双振动电机的相位同步控制策略。双振动电机在振动机械,如振动筛、振动打桩机及振动成型机等,有着广泛的应用。现代的双振动电机以相位控制同步方式工作,而目前采用的主要是主从跟踪式PID控制同步方法。这种方法虽然实现简单,但控制效果较差。基于最优跟踪控制技术,在状态空间中对双振动电机系统的振动频率和相位差同时进行控制,取得了较满意的实验结果。该控制技术可以很方便地被推广到对3台以上的振动电机进行多机相位同步控制中。     

Organometallic L-Alanine Cadmium Iodide Crystals for Optical Device Fabrication

Single crystals of L-alanine cadmium iodide (LACI) were grown by the slow evaporation technique at room temperature. A single-crystal X-ray diffraction (SXRD) model was used to evaluate the crystal structure of the as-grown LACI crystal. The energy dispersive X-ray (EDX) analysis and ultraviolet-visible-near infrared (UV-vis-NIR) transmittance studies were carried out, and the results reveal the presence of elements in the title compound. From the transmittance data, the optical bandgap as a function of photon energy was estimated, and the different optical constants were calculated. A fluorescence study was performed for the LACI crystal. Thermogravimetric and differential thermal analyses have also been studied to investigate the thermal property of the LACI crystal. The efficiency of the second harmonic generation (SHG) of the title crystal was investigated. The magnetic and electrical properties were estimated by the vibrating sample magnetometer (VSM) analysis and impedance study, respectively.     

Understanding the galvanic corrosion of the Q-phase/Al couple using SVET and SIET

The galvanic corrosion of the Q-phase/Al couple in 0.1 M NaCl solutions has been studied using the scanning vibrating electrode technique (SVET), the scanning ion-selective electrode technique (SIET) and energy dispersive X-ray spectroscopy (EDX). The galvanic corrosion of the Q-phase/Al couple was found to be dependent on pH and immersion time. Current density maps obtained by SVET shows that the anodic oxidation processes emerge from Al in a localized manner in pH 2 and 6 solutions but is initiated in a uniform manner in pH 13 solution, whereas, the cathodic processes are more homogeneously distributed over the Q-phase at pH 2, 6 and 13. It is seen that the Q-phase remains cathodic in the Q-phase/Al couple in acidic, neutral and alkaline solutions indicating that the galvanic polarity of the Q-phase is independent of pH. The effect of the galvanic corrosion was largest at pH 2 and 13 compared to pH 6. The pH map obtained by SIET indicates that the galvanic activity of the Q-phase/Al couple proceeds via heavy alkalization of the Q-phase surface with the generation of appreciable amounts of OH⁻ ions. The enrichment of Cu indicated by EDX is responsible for the observed cathodic activity of the Q-phase in the Q-phase/Al couple.     

Parameter estimation and stabilization for a wave equation with boundary output harmonic disturbance and non‐collocated control

This paper is concerned with the parameter estimation and stabilization of a one‐dimensional wave equation with harmonic disturbance suffered by boundary observation at one end and the non‐collocated control at the other end. An adaptive observer is designed in terms of measured velocity corrupted by harmonic disturbance with unknown magnitude. The backstepping method for infinite‐dimensional system is adopted in the design of the feedback law. It is shown that the resulting closed‐loop system is asymptotically stable. Meanwhile, the estimated parameter is shown to be convergent to the unknown parameter as time goes to infinity. Copyright © 2010 John Wiley & Sons, Ltd.     

高灵敏度圆柱壳体振动陀螺的研究

灵敏度是陀螺的重要性能指标,灵敏度的提高可以直接带动精度提高,同时可以拓展陀螺的应用范围。影响圆柱壳体振动陀螺灵敏度的因素很多,本文通过考虑了科里奥利效应(Coriolis effect)的ANSYS谐响应分析,提取产生陀螺效应的圆柱壳体振动陀螺的输出位移,通过比较不同形状谐振子相同激励条件下的输出位移大小来反映灵敏度的大小。采用这种方法分别研究谐振子的各项参数对于陀螺灵敏度的影响规律,并基于仿真结果设计了高灵敏度的参数优化圆柱壳体振动陀螺谐振子,通过实验验证了该谐振子的高灵敏度。     

硅微机械振动轮陀螺仪非线性动力分析􀀁

本文简单介绍了硅微机械振动轮陀螺仪的工作原理,并给出了该陀螺仪的非线性运动方程和线性化运动方程．针对该陀螺仪的运动方程,进行了数值仿真研究．根据数值仿真结果,还提出为了提高测量的线性度必须采用闭环控制．同时,还给出了闭环控制的方案．