Aerosol Measurement in Low‐Pressure Systems with Standard Scanning Mobility Particle Sizers

The scanning mobility particle sizer (SMPS) is one of the best known instruments for measuring particle size distributions in the submicron range. The SMPS consists of two parts: an electrostatic aerosol classifier (differential mobility particle analyser, DMA), followed by a counting device, in general a condensation particle counter (CPC). Unfortunately, commercial measurement devices such as the TSI DMA Model 3071 and the TSI CPC Model 3022 (TSI Inc., St. Paul, MN, USA), can be used only at nearly atmospheric pressure in the sampling line or in slight overpressure mode, but not in low‐pressure systems. A modification in the sampling line is shown which enhances the operating range of a standard SMPS system to low pressure. Samples taken under standard and low‐pressure conditions show good agreement in the measured particle size distributions and concentration. The behaviour observed in experimental studies agrees well with theoretical predictions.     

First experimental research of the bunch compressor at CAEP

Magnetic bunch compressor is one of the key technologies on the path to next generation accelerator driven facilities. In this paper we report the design principles and the first experimental research of the bunch compressor developed at Chinese Academy of Engineering Physics （CAEP）. The length of the bunch after compressor is found to be about 0.7 ps （rms） and the peak current exceeds 500 A when operated in the optimized condition. The sensitivity of the bunch length on the phase of the acceleration field and magnetic field of the bunch compressor was also measured and analyzed.     

The temporal Mueller matrix solution for polarimetric scattering from a layer of random non-spherical scatterers

The Mueller matrix solution of the vector radiative transfer equation with time dependence is derived in this paper. It is applied to simulation of polarimetric bistatic scattering from a layer of non-uniformly oriented, random non-spherical scatterers when a Gaussian plane pulse is incident upon. Co-polarized and cross-polarized bistatic scattering are numerically calculated. The pulse echoes are compared with the incidence, and demonstrate its functional dependence on the physical parameters of random medium, such as spatial orientation and fractional volume of scatterers, incidence angle and polarization, the layer depth and others.     

A scanning superconducting quantum interference device microscope for room temperature samples

We have constructed a scanning low-T_c superconducting quantum interference device (SQUID) microscope, in which the SQUID is mounted on the lower end of a copper rod and cooled to liquid helium temperature. There is a 65μm thick sapphire window under the SQUID. The sample at room temperature underneath the window can be scanned to produce magnetic images. The microscope has a spatial resolution of 100－150μm and a magnetic field sensitivity of 3－60pT/$\sqrt{Hz}$ in a magnetically unshielded environment. We have used this scanning SQUID microscope to measure various room temperature samples.     

同步镀铋膜差分脉冲伏安法测试土壤中铬

采用同步镀铋膜法修饰玻碳电极及差分脉冲溶出伏安法测试土壤中Cr。在优化的实验条件下,以KNO3为支持电解质,NaAc-HAc(pH=5.5)为缓冲溶液的铋膜上得到Cr溶出特征峰电位为-1.14V,线性方程为:I=0.0747C+0.31054,相关系数为0.9981,检出限为0.001μg/L,线性范围为0.01—60μg/L,RSD=2.47%,该方法简单快速,准确度和精密度均符合要求,回收率为96.7%—104.5%。     

基于线偏振光反射率测量介质折射率的研究

研究线偏振光的振幅反射率与介质折射率的关系,提出一种测量介质材料折射率的方法。文中从菲涅耳公式出发,推导出各向同性介质的线偏振光反射率与折射率的关系式,给出基于线偏振光反射率测定介质折射率的原理。设计实验方案,在不同入射角情况,定出线偏振光p方向和s方向两种线偏振光在玻璃表面的反射率,得到线偏振光振幅反射率随入射角变化的实验曲线。依此实验数据得出材料的折射率。结果表明,测出的介质材料的折射率与理论值相符,所采取的测定方案可行。     

基于北斗/iNEMO惯性模块的机器人运动姿态解算方法

基于北斗/iNEMO惯性模块研究了一种组合式机器人运动姿态测量系统和解算方法。设计了以ARM为核心的嵌入式组合姿态解算平台,通过四元数法和卡尔曼滤波技术,对iNEMO惯性组件测量数据进行融合,进而在高动态环境中实时解算出机器人的运动姿态。同时,以北斗接收机输出的1PPS上升沿脉冲作为数据融合的同步信号,并利用其输出的导航信息辅助iNEMO惯性模块实现精对准。测试结果验证了设计方案的可行性和正确性,为机器人姿态解算提供了一种高精度、高稳定性、小体积、低功耗的解决方案。     

基于区域生长重心的大型多阵列圆标定板基准点的提取技术

针对视觉测量在轨道交通隧道大范围轮廓测量上的问题,研究设计一种大型多阵列圆标定板进行系统标定工作,提出区域生长重心法实现对标定图像上基准点的提取。即将区域生长法和灰度重心法相结合,通过粗定位寻找每个基准圆的种子点,考虑种子点像素的4邻域像素进行区域生长,然后利用灰度重心法提取生长区域的重心作为基准点。将非线性变化的基准点替代线性提取的基准圆的种子点,消除了图像畸变的影响,保证了特征检测过程的可靠性和鲁棒性,达到对于多阵列圆大型标定板基准点的提取。通过搭载鱼眼镜头拍摄6m的模拟隧道横断面轮廓,进行轮廓测量与还原。实验表明该方法提取的基准点像素坐标误差可达到2pixel以内,系统测量精度能够达到±5mm以内,完全满足轨道交通隧道横断面轮廓测量误差标准。     

基于FPGA反射式激光双速测量系统的设计与实现

物体在运动时旋转,可以减小物体运动过程中的空气阻力,增加运动运动稳定性,提高发射效率。而在一些发射系统中,弹丸在运动的过程中,也会发生旋转。通过测量弹丸的旋转速度和运动速度,可以更好的了解弹丸运动规律、调控运动行为,获取即时环境信息。文中提出了一种高灵敏度反射式测速系统,该测速系统采用高速响应数字激光传感器作为测量器件,采用FPGA编程进行控制和运算,具有抗低频电磁干扰的优点。应用该测速系统可以同时测量电磁发射系统中弹丸在出口处的水平运动速度和旋转速度。     

Real-time surface profile measurement using a feedback type of sinusoidal phase modulating interferometer

In this paper, we propose a sinusoidal phase modulating (SPM) interferometer that is insensitive to external disturbances, and its measuring principle is analyzed theoretically. In the SPM interferometer, the interference signal is detected by a high-speed image sensor based on a low-speed CCD and a signal processing circuit is used to obtain the phase of each point on the surface. Therefore, the surface profile can be measured real-time. The experiments measuring the surface profile of a wedge-shaped optical flat show that the measurement time of the SPM interferometer is less than 10 ms, the repetitive measurement accuracy is 4.2 nm. The results show that the impacts of nonlinear distortion of the piezoelectric transducer (PZT) and part external disturbance are removed.