基于CPW的油水两相流持水率检测方法研究

为了提高原油的开采效率,各油田越来越多地采用注水采油的措施和水平井开采的方法。这对井下油水两相持水率的在线检测提出了更高的要求,其一要求传感器在高持水条件下具有与低持水段一样高的检测精度,其二要求单支传感器体积结构小,便于在油井截面上布置多支传感器形成检测阵列,提供水平井或大斜度井油水截面上持水率分布的差异信息,提高测量的空间分辨率。为此,提出基于共面微带传输线的油水两相流持水率检测方法。通过保角变换法分析了共面微带传输线传感器的结构参数和材料参数与电磁波传播特性之间的关系,采用片状双面S形布线结构,在小型化传感器的同时提高了检测的动态范围。数值模拟和实验结果表明,信号在传输线上的相移与持水率间具有近似线性的关系,传感器在持水率0%~100%全程范围内具有小于3%的分辨率,该方法弥补了电容法和电导法仅适合于低持水率和高持水率的弊端。     

薄膜谐振Lamb波传感器测量液体流速矢量的方法

针对液体流速测量领域中微型流量传感器高品质因数、高灵敏度的性能要求。本文设计一种双端增强型薄膜谐振结构实现Lamb波传感器的高品质因数,利用传感器反对称模式(A01模式)在薄膜-液体界面处的消逝波实现液体流速矢量测量。所制作的双端增强型薄膜谐振Lamb传感器A01模式的主峰品质因数为703,A01模式的频率移动量与液体流速大小存在线性关系,频率移动方向与液体流动方向存在对应关系。流速实测灵敏度约为270 Hz/mm/s,传感器稳定性噪声小于0.2Hz,流速最低检测极限值(LOD)为2.2μm/s,流量最低检测极限值(LOD)为18.3nL/min。结果表明,双端增强型薄膜谐振Lamb波传感器可以实现液体流速高灵敏度矢量测量。     

基于DSP的中药丸料湿度密度在线检测系统

设计与研制一种能在现代化中药制药生产线上在线连续测量中药丸料湿度与密度的微波检测系统。系统包括三个组成模块：微波信号源模块，微波谐振腔，数据处理模块。其中，微波谐振腔是专门设计用于中药丸料湿度与密度检测的中心开通孔的金属谐振腔，当中药丸料通过微波谐振腔的中孔时，丸料密度及湿度均令谐振腔的谐振频率产生偏移和功率衰减，数据处理模块据此计算中药丸料的湿度与密度。为提高检测精度，采用模糊聚类算法对实验数据进行分组，对金属谐振腔的频偏和功率衰减特性进行建模，并利用DSP设计并实现了中药丸料湿度与密度的在线检测。现场调试表明：该检测系统适宜于现代化中药制药生产线上的湿度连续在线测量，其检测精度达到93％以上。     

同轴线式相位法测量油井含水率

本文利用同轴传输线作传感器，测量油水混合水质的相位系数，研制了同轴线式相位法找水仪，从而得到油水混合介质的持水率。该仪器还实现了油井持水率以往难达到的连续测量，室内模拟井试验和初步现场试验看出本文提出的含水率测量新方法颇有前途。     

粮食水分在线测量传感器

研制了一种基于电容测量的粮食水分含量在线测量传感器。提出了一种新的传感器结构并给出了数学模型,通过理论分析和ANSYS仿真实验给出了传感器的结构参数;同时,介绍了传感器信号调理电路的软件、硬件设计。实验测量结果表明:粮食(小麦)水分含量在10%~18%时,传感器测量精度优于0.5%。传感器具有RS-485总线通信接口、体积小、粮仓内布放简单等特点,适用于粮仓在线测量。     

调相式光纤电流传感器中传感头的设计

在以压电效应为传感机理的调相式光纤电流传感器中，必须首先将电流信号转变为电压信号，再以此电压信号驱动压电陶瓷筒，使缠绕在筒上的光纤中光波的相位发生变化。一般采用低压电流互感器（CT）实现电流－电压转换。这种方法由于CT本身的绝缘性不好，易出现磁饱和、转换电压不高等原因，使传感器的性能受到影响。文中提出一种新的传感头设计方法。它以Rogowski线圈代替传统CT，作为电流－电压转换装置，提高了传感器的精度、可靠性及测量范围。     

基于微波谐振器的谷物湿度检测系统

设计和研制一种能连续测量谷物湿度的微波检测系统.提出利用微波谐振器的干扰特性测量谷物的湿度,并设计专用于谷物湿度检测的中心开通孔的微波谐振器.当谷物颗粒通过微波谐振器的中孔时,其质量和湿度都令谐振器的谐振频率产生偏移和功率衰减,谷物的质量和湿度两者所引起的谐振频率偏移和微波功率衰减是相对独立的,在同一湿度下谷物的质量仅仅与微波功率的衰减量有关.因此在得到谐振频率的偏移量和微波功率的衰减量后,就可以计算谷物的湿度.在大量试验的基础上,对试验数据进行模糊聚类,从而对微波谐振器的频偏和功率衰减特性进行建模,据此设计并研制了谷物湿度的微波连续检测系统.试验调试表明:该检测系统适宜于谷物的连续湿度检测,检测精度达到92%以上.     

Soil moisture assessment by means of compressional and shear wave velocities: Theoretical analysis and experimental setup

In previous works, the authors presented the outline of a method for measuring the moisture content in agricultural soils via elastic waves, along with experimental results obtained on a specimen of sandy soil. This work illustrates other aspects and results of the research, regarding both the underlying theory and the design and realization of an improved measurement system. Firstly, the derivation of the simplified equations which are at the basis of the moisture measurement is thoroughly illustrated and discussed, starting from the more complex (and generally unmanageable) equations of elastic waves in unconsolidated porous media. The analysis suggests that by measuring the velocities of low-frequency compressional and shear waves in soils, it is possible not only to measure the water content, but also the uniformity in the water distribution. Secondly, the design and the practical realization of an experimental setup, which is able to measure the velocity of compressional and shear waves in soils, is illustrated in detail. The use of custom-built compressional and shear waves electromechanical actuators, together with geophones, low noise preamplifiers, and suitable signal processing techniques, brought to the realization of an effective and reasonably accurate measurement system.     

多读数头混合布局测角误差抑制方法

在不增大码盘尺寸的前提下,对测角传感器读数头的布局展开研究,以研制小型化高精度的测角传感器。本文基于测角误差的谐波分析结果,详细推导和分析了多读数头布局对角度测量误差的抑制原理。通过对几种典型多读数头布局方式进行深入研究,提出一种采用奇数头和偶数头相结合的读数头混合布局方式,以消除更多更高阶次误差,提高测角传感器的精度。实验结果表明,当采用三个、四个和六个读数头均匀布局形式时,测角传感器的测角精度分别为15.44″、9.72″和8.96″;当采用六个读数头优化布局的方式时,测角精度可达到7.7″。上述结果说明多读数头优化布局可有效抑制测角误差,提高测量精度。     

新型油井含水率测量仪的研制

由于水、油介电特性差异较大，导致电磁波在不同含水率的油水混合介质中传播时的相位系数有很大不同。新型含水率测量仪器是利用同轴线作传感器，油水混合介质在同轴线内流过，并构成传播电磁波的载体，通过测量同轴线两端电磁波在同轴线内油水混合介质中传播的相位系数，来得到油水混合介质的含水率。该仪器能够实现油井含水率的连续测量，室内试验和初步现场试验证明该方法能够解决高含水油田油井含水率很难测准这一难题。     

智能视频分析在输电线舞动监测中的应用

为了获得有效的测量信息,建立架空输电线舞动自动监测系统,采用图像与视觉分析方法,提出了一种智能视频分析在舞动监测中的应用的系统设计。该方法采用固定于杆塔上的摄像头拍摄杆塔和电缆图像,在电力线上加装参照物的方法增强识别效果,采用智能视频分析算法获得舞动轨迹、幅度与角度。该系统通过ZigBee技术构建无线传感器网络进行可靠通信,采用风光互补供电方式保证野外供电的持续可靠。为输电线舞动的动态监测与预警提供了一种新的方法和思路。     

Full-Wave Modeling of Microwave Planar Reflection Sensors for Material Moisture Testing

The main design aspects of two new, nearly complementary, planar reflection sensors for material moisture content measurement in the industrial environment are reported in this paper. The former is structured as a resonant microstrip ring interacting with the material under test (MUT) mainly through evanescent near fields, while the latter consists of a cavity-backed slot that couples to the MUT by radiative near fields. The sub-surface sensor-MUT interaction is numerically modeled in both cases by resorting to a full-wave electromagnetic (EM) approach based on the method of moments (MOM). If compared to the usual quasi-static approach, this method allows a more physical insight about the field-target coupling phenomena and a better accuracy in extracting the observable electrical parameters. A comparison between the two sensor types was made in order to address each sensor to its specific application field. In particular, the parametric sensitivity of both sensors to the most frequently recurring measuring artifacts was numerically analyzed. Finally, a prototype for each sensor type was constructed and experimentally tested in order to validate the results of the EM simulation.     

Low Cost Microwave Sensor for Moisture Content Measurement in Paper Milling Industry

The interest about RF and microwave sensors for the measurement of dielectric properties of materials during industrial processes has been growing recently. Microwave sensors are particularly attractive for their ability of performing non-invasive measurements. An interesting field of application is the real-time moisture measurement during industrial processes. A smart active sensor for measuring the moisture content of felts used in the paper milling industry and more generally of sheet-like materials, is here proposed. The sensor consists of a cavity backed slot resonator interacting with the material under test through near fields. The design aspects of the sensor and the related measuring front-end are discussed with respect to the dielectric properties of the material, and to the resonator response. The parametric sensitivity of the measuring method with the distance between the sample and the sensor surface and the sample thickness is also analyzed. An inversion procedure based on an Artificial Neural Network (ANN) approach is proposed in order to determine the moisture content of the felts. Measurements on several reference felts, with different density, thickness, and moisture content levels, ranging from dry to waterlogged state, proved the effectiveness of the proposed sensor architecture and the ANN-based inversion procedure.     

一种改进型负载线移相器MMIC的设计方法

在采用传统微带线负载移相器设计小相位数字移相器时,遇到了负载线宽过窄的问题,而一般半导体工艺很难实现。在此基础上,提出了一种改进型微带线负载移相器的设计方法。该移相器主传输线的两端各挂载一个相同输入阻抗的开路支节,通过调节支节的阻抗值使移相器的输入／输出反射损耗达到最小;通过加载两个开路支节,在同样的相移量下,加宽负载线的宽度,提高产品的成品率。利用此设计的移相量为11．25°,同时数字移相器的实验结果验证了该设计方法的正确性和可行性。     

Temperature effect on the reference frequency of FDR soil moisture sensor

The FDR automatic soil moisture sensor must determine reference frequency in the air and water. Experimental studies show that the water reference frequency is influenced by water temperature. The variation of the reference frequency of the sensor is measured with the change of the water temperature,then analysis the influence of the volume water content measurement of the sensor,analysis found that the error is not more than 3% for the measurement of the volumetric water content of the temperature.     

非接触式缸盖平面度误差检测方法与测量系统研究*

为解决发动机缸盖生产铸造过程中缸盖底面平整度误差检测问题,设计一种激光非接触式发动机缸盖底面平整度在线检测系统,提出一种基于对角中线的平面度误差检测算法。根据现场平面度检测需求,设计利用激光臂纵轴和缸盖横轴传送的交互运动的发动机缸盖表面平面度误差检测系统;通过发动机缸盖表面检测四个顶角特征点对角线中线建立发动机缸盖平面度检测的数学模型,利用回归方程确定最小二乘法平面为理想平面,求出平面度误差;并对激光位移传感器进行精度标定,给出传感器误差标定回归方程,并应用该检测系统完成对不同型号的发动机缸盖检测。结果表明：该系统最大检测面积为400 mm×2 000 mm,测量范围为160~450 mm,测量精度为0.03 mm,而且结构简单,检测速度快,完全能够达到在线检测要求。     

复合基质结构优化设计下的应变测量灵敏度提高研究

针对当前微带天线传感器应变测量灵敏度较低的问题,对基质结构进行研究,设计了一种带空气层的复合基质天线传感器.结合遗传算法应用HFSS软件对传感器结构参数进行优化设计,仿真研究最优解下的复合基质天线传感器"谐振频率-应变"关系.对所设计的复合基质天线传感器进行拉伸对比试验,其应变测量灵敏度是传统微带贴片天线传感器的3.1...     

Generation of velocity profiles with speed limit of each axis for high-speed machining using look-ahead buffer

An efficient look-ahead algorithm to generate velocity profiles is presented in this paper. Algorithm allows for a nonzero starting point velocity and end point velocity of every line segment to increase machining productivity. The paper considers the intelligence of look-ahead to achieve faster machining speed, along with required accuracy. Speed limitation of a specific axis and the direction change of an axis are newly added to the constraints of the velocity profile problem. This paper solves graphically the problem of generating velocity profiles and derives the equations for representing the velocity profile. A method to manage the look-ahead buffer is also proposed. To generate velocity profiles using the look-ahead buffer, three phases are proposed. Phase 1 determines the velocity conditions such as the maximum velocity, starting point velocity and end point velocity. In phase 2, velocity profiles are generated independently. Phase 3 handles the change of the start or end point velocity. This phase 3 is repeated until all adjacent point velocities are the same. The proposed method was utilized in the manufacturing field to engrave aluminum tire molds. It was demonstrated that this method contributes to an increase of the machining accuracy and a reduction of the production time.     

基于分时方法的高精度反射绝对式 纳米时栅位移传感器设计

本文提出了一种反射绝对式纳米时栅位移传感器的传感方法。采用反射单列式传感器作为反射绝对式传感器的精密测量部分,记为传感器A。为了实现绝对位移测量,设计了一个与传感器A相差一个周期的反射单列式传感器,记为传感器B,利用传感器A与传感器B相位作差实现绝对位移测量。采用标准印刷电路板技术制作了传感器样机,搭建了实验平台,进行了实验测试。测试结果表明,激励电极引线方式对接收电极带来干扰,从而造成一次谐波误差。为了抑制误差,提出了交叉反射结构和分时方法,交叉反射结构将感应电极与另一端的反射电极引线相连,增大激励电极和接收电极的距离,分时方法通过不同时间段对传感器A和传感器B施加激励信号,并把不工作的电极接地。实验表明该结构和方法相互配合有效的抑制了干扰,最终在400 mm范围内,补偿后实现了±300 nm的测量精度。