交叉偶极阵列声波测井仪控制和处理电路的设计与实现

针对交叉偶极阵列声波测井信号的特点,设计了一种以DSP+FPGA架构为核心的控制和处理电路。详细介绍了电路的硬件结构和软件设计流程,重点描述了测井数据通信接口和逻辑控制模块的实现,并给出了一种首波提取算法。实验结果表明,该电路在井下高温高压恶劣环境中能够稳定可靠地长时间工作,完全满足工业生产作业的需要。     

高精度相位法超声测距系统研究

为了提高超声波测距仪的测量精度,介绍了利用超声波相位差进行测距的原理,提出了一种新颖的利用超声波相位差进行测距的技术。该技术采用单片机完成超声波的产生和发射,利用计数器和相位比较器得出测距结果,并通过实时测量环境温度修正超声波传播速度,提高了该超声波测距系统的精度。完成了该测距检测系统的硬件软件的设计,并进行了详细的理论和实验研究。实验结果表明:提出的设计方法精度高、重复性好、可靠性高,具有较好的应用前景。     

近红外动脉血液检测中压力对脉搏波的影响

近红外血液检测技术中,透射式光电容积脉搏传感器具有携带有效信息量大的优点,可为动态光谱检测理论提供有效采样数据,但实际应用受到个体差异性的限制.为了克服不同手指端厚度给传感器带来的检测难题,分析了检测结果中压力与直流分量及交流分量之间的关系,通过不同厚度的手指测试实验,指出了存在一个最佳检测区域使得检测到的脉搏波处在最理想状态.     

高频斩波串级调速系统建模与动、静态特性分析

与传统控制方式不同,斩波串级调速在回路拓扑结构和主回路工作方式上变化较大,因此需要详细分析其调速机理和系统动、静态特性,从而为其工程设计提供理论依据。首先介绍了高频斩波串级调速系统的工作原理,利用状态空间平均法分析了主回路各参量基本输入输出关系,得到了平均状态下的主回路简化数学模型,结合串级调速下负载电流与转矩关系以及异步电动机机电运动方程,得出了高频斩波串级调速系统的简化动态模型,并在此基础给出了系统调速的开环动态结构图,分析了斩波串级调速系统的动、静态特性,为进一步分析系统闭环控制及工程设计提供了理论基础。     

物位计测量技术分析及应用研究

雷达物位技术是物位测量技术中发展较快的技术之一,但我国雷达物位仪表的研发还比较落后。分析了雷达物位计市场所占比重最大的两种测量方式——雷达脉冲测量和连续波线性调频测量的信号处理方式,比较了它们各自的优缺点,并指出了在应用中应注意的问题;同时,探讨了物位计开发过程中的技术难点,并根据我国现有的技术条件提出了相应的解决方案。     

Evanescent wave sensor based on permanently bent single mode optical fiber

A novel refractive index sensing scheme based on evanescent wave interaction through locally and permanently bent single mode optical fibers is proposed. Local and permanent bends in single mode optical fibers enable significant power coupling between core and cladding modes. Order and number of excited cladding modes depend on bend features and determine the field profile at the output of the bent region. This in turn constitutes a simple mechanism to tailor the field distribution in single mode optical fibers useful for spatial light modulation. Moreover, since guided cladding modes are strongly influenced by the surrounding refractive index (SRI), the power transmitted at the output of the bent region as well as its dependence on the optical wavelength are strongly sensitive to the SRI opening new scenarios in sensing applications.     

Determination of lysozyme at the nanogram level in chicken egg white using Resonance Rayleigh-scattering method with Cd-doped ZnSe quantum dots as probe

A new method for the determination of lysozyme with high sensitivity based on Resonance Rayleigh scattering (RRS) by using Cd doped ZnSe quantum dots (QDs) as a probe was proposed in this experiment. Cd doped ZnSe QDs capped with glutathione were prepared in the water phase. Further, the RRS spectrum, transmission electron microscope, and absorption spectrum of the QDs-lysozyme system have been characterized. In addition, the effects of several factors on scattering intensities were investigated, including pH value of solution, amount of QDs, mixing sequence of each reagent and the coexisting substances. Moreover, the possible mechanism for the RRS enhancement of Cd doped ZnSe QDs-lysozyme system was preliminary discussed. The RRS method for the determination of lysozyme has good sensitivity with the detection limits 6.5 × 10⁻¹⁰ g mL⁻¹. The contents of lysozyme were determined with recoveries of 97.1-101.6% and relativity standard deviation of 2.5-3.1%, respectively. It proved that the method established in our study is very sensitive, rapid, convenient and tolerant for the determination of lysozyme in synthetically and chicken egg white.     

基于ARM920T内核的雷达测速仪设计与算法研究

为了提高目前公路交通中对车辆速度的监测手段,提出一种基于ARM(advanced RISC machines)的新型雷达测速仪,结合多普勒测速原理和信号处理的谱估计法,介绍了由毫米波多普勒收发前端和SamsungS3C2410A处理器构成的雷达测速仪的整体设计,包括其硬件结构的设计和在ARM920T内核中实现基4时间抽取的快速傅里叶变换算法(fastFouriertransform,FFT)。实验结果表明,该雷达测速仪的测速精度可达±1km/h,其优化后的FFT算法具有很高的精度和运行效率。     

一种新型本征倏逝波型光纤传感器的研究

研究开发了一种新型本征型光纤倏逝波传感器.采用有机玻璃板和大半圆弧高抛光PVC管构成光纤支架,将60/125 μm阶跃多模光纤隔一定距离剥除等长度涂覆层后缠绕于光纤支架上,其无涂覆层部分位于上下两PVC管之间,经化学腐蚀后获得裸芯总长度大于0.5m的新型高灵敏本征型光纤倏逝波传感器.实验结果表明:该传感器对亚甲基蓝的探...