一种新的多频连续波雷达数据采集系统设计

给出了一种基于多速率信号处理的多频连续波雷达数据采集系统设计和实现方法。分析了抽取的时域和频域特性,针对多频连续波雷达的应用背景,分析了实际系统中抽取比的选择,设计了合适的抗混叠滤波器。给出了一种FIR实现信号抽取的高效结构。在此基础上,完成了数据采集系统的硬件设计和软件设计。该方案具有控制灵活,数据传输高速、稳定等特点。该设计已经成功应用于实际系统。     

共光路双频外差干涉法测量模拟磁头磁盘静态间隙

提出了一种共光路外差干涉测量模拟磁头磁盘静态间隙的方法，该方法以低频差横向塞曼双频激光器作为光源，采用专门设计的双折射透镜分光和相位测量技术，实现了对光波半波长的3600细分，从而使测量分辨率达到0．1nm。原理实验结果表明，该系统在无恒温的普通实验室条件下，1h内稳定测量实验结果漂移小于4nml利用压电陶瓷（PZT）微动工作台（步进分辨率1nm）驱动反射镜（模拟磁头）产生位移，在1μm范围内与该系统测量结果进行比对，得到线性相关系数优于0．9998。     

FLOW-BASED CHARACTERIZATION OF THE OPERATION OF A MICROFLUIDIC AMPLIFIER

This article analyzes the performance of jet deflection microfluidic amplifiers implemented in silicon, using microchannels with a minimum hydraulic diameter of ~40 w m. The implemented devices were characterized in terms of applications involving flow control and flow division. The implemented devices presented proportional or symmetrical behavior. For proportional control, high flow gains were obtained, similar to fluidic amplifiers with supply hydraulic diameters of hundreds of micrometers, being the average flow gain a function of supply flow. Numerical simulation analyses of the active part of the devices indicate the possibility of choked flow at the output of the supply nozzle.     

Differential interferometry in heat transfer

In this paper the optical methods in heat transfer applications are described briefly. In particular, interferometric methods are discussed in detail as applied to the study of natural convection heat transfer. Of the most popular interferometers, viz. the Mach Zehnder Interferometer (mzi) and the Differential Interferometer (di), thedi is considered in detail. The theoretical and constructional features of adi are outlined. The procedures of heat transfer measurement and the temperature profile estimation are explained. The advantages and limitations of the two interferometers are compared with the help of a sample calculation. The experimental analyses of three cases, viz. (1) isothermal vertical flat plate, (2) single vertical fin attached to a heated horizontal base, and (3) horizontal fin array, are described. Typical heat transfer and temperature profile results are presented. Using the estimated temperature profiles isotherms are plotted. It is possible to get fairly good heat transfer and temperature profiles using adi. The instrument is specially useful in applications involving short optical path lengths because of its superior resolution as compared tomzi.     

基于激光干涉法的曲率半径精密检测系统

为了满足光学元件曲率半径精密检测的需求,设计了应用激光干涉方法的曲率半径精密检测系统,实现了对口径100~300 mm,曲率半径500~2 000 mm光学元件曲率半径的高精度,非接触式测量。并分析了影响曲率半径测量结果的各项不确定度,进行不确定度合成。最终完成曲率半径精密检测系统的装调,进行验证实验,曲率半径测量结果相对不确定度约710-6,满足了1010-10的设计要求。     

基于DDS技术的模块化多频涡流检测系统设计

多频涡流检测技术能有效地抑制无损检测过程中的干扰因素,提高检测的分辨率和可靠性.DDS技术是频率合成的新技术,因此,在对多频涡流检测系统进行模块化划分的基础上,设计了基于DDS技术设计信号发生模块,基于VCVS的有源带通滤波模块和模拟正交锁定放大模块等,系统整体具有易于集成和重构的特点.实验结果证明:该系统工作稳定,可用于100 Hz～1 MHz范围内的多频涡流无损检测.     

新一代尾矿干排工艺和设备的应用

简要介绍了目前国内常见的几种尾矿干排工艺, 主要论述了鑫海第三代尾矿干排工艺和主要设备, 并以4 000 t/d尾矿干排为例对不同尾矿干排方式进行了比较。分别对鑫海浓缩脱水型水力旋流器、高效深锥多锥浓密机、高效多频脱水筛适用于矿浆脱水的原理进行了分析。     

基于数字散斑剪切干涉术的三维面型测试

基于数字散斑剪切干涉术的原理, 研究了物体面型的三维测试技术。使用倾斜反射镜的方法, 使物光束散斑场偏转,再由CCD记录偏转前和后物光束的散斑场。这种方法代替了传统的使用剪切元件空间上直接获得干涉条纹图, 减少了由于剪切元件分束引起的物光束的光能损失, 实现了数字散斑剪切干涉术测量物体面型。应用MATLAB软件编程, 控制剪切散斑干涉图的精确定向平移, 得到了4个干涉图, 实现了数字四步相移, 代替了传统的在参考光中利用位相控制器的机械相移, 从而实现了物体面型的三维测试。该方法不仅省去传统剪切散斑干涉术中需要对感光胶片进行化学湿处理的过程, 也省去了压电位移器等硬件。大量的实验表明, 该方法不仅简化了测试光学系统和实验的过程, 也提高了测试精度, 其精度可达到1/10波长。     

Speckle interferometry for materials testing under extreme thermal conditions

The range of application of a non-contacting optical technique, speckle pattern interferometry, has been extended to high temperature testing. Extreme thermal conditions cause disturbances that have been studied systematically. Based upon these pre-tests, two prototype systems were developed and they proved well-suited for measuring a field of strain data up to 1500°C and also during rapid heating or cooling. Various examples illustrate the new possibilities in materials testing.