Calibration of the operating parameters for an HB5 stem instrument

The interference fringes, or electron Ronchigrams, appearing in the shadow images of thin periodic objects may be used for calibration of the operating parameters of a scanning transmission electron microscopy (STEM) instrument. The determination of the spherical aberration constant is more simple and direct than by other means used in electron or light optics. The calibrated value for the spherical aberration may then be used in the determination of other primary aberrations.     

Calibration of an ultrasonic flow meter for hot water

If we want to keep the number of necessary characterisation measurements within acceptable limits, we need to be confident that a flow instrument design reacts in a predictable and straightforward way to systematic influences. In this paper, the important systematic influences for an ultrasonic flow meter (UFM) for feed water flow are identified to decide which characterisations have to be carried out in addition to a typical baseline calibration with water at 20 °C. In heat metering applications where there are temperatures up to 120 °C it is for example known that the temperature influence on the flow instrument is important and this also applies to higher temperatures such as in the feed water control of power plants. One of the critical systematic temperature influences that affects most flow instruments is the thermal expansion of the meter body. From June 2009 to March 2010, the “Heat and Vacuum” department of the Physikalisch-Technische Bundesanstalt conducted a measurement campaign to characterise the influence of thermal expansion of a meter body on the calibration of an 8 inch (DN 200) five chord UFM for feed water application in the temperature range from 4 °C to 85 °C and flow range from 50 m³ h⁻¹ to 900 m³ h⁻¹. An overview of the procedures and facility used for the calibration is given and the measurement conditions under which the calibrations were performed are detailed. It is shown that a linear model of the thermal expansion effect is appropriate for the investigated conditions.     

Calibration of an imaging crystal spectrometer for low x-ray energies

An x-ray imaging crystal spectrometer was designed for the Hanbit magnetic mirror device to observe spectra of heliumlike neon at 13.4474 A. The spectrometer consists of a spherically bent mica crystal and an x-ray sensitive vacuum charge coupled device camera. This spectrometer can provide spatially resolved spectra, making it possible to obtain profiles of the ion charge state distribution from line ratios and profiles of the plasma rotation velocity from Doppler shift measurements. The paper describes measurements of spectral resolution of this instrument for low x-ray energies.     

Calibration of an image-tube picosecond dissector

This paper describes a new image-tube dissector based on a PIF-01 chronographic image-tube device developed and manufactured at the Prokhorov General Physics Institute of the Russian Academy of Sciences (PGPI RAS). The results of the static measurements of the instrumental function of the dissector showing that its temporal resolution can be higher than 4 ps are given. These data are confirmed by direct measurements on the bench of the PGPI RAS with the use of a femtosecond titanium-sapphire laser.     

表源一体化电能表检定装置

本文重点介绍一种便携式三相电能表检定装置的性能、原理及设计特点.本装置在软、硬件设计时将程控源与标准表融为一体,由一套8031微机系统控制,实现了程控功率电源与标准功率电能表的参数、测量数据自动识别与共享,简化了电度表校验操作.     

基于多幅标定板图像的摄像机标定的对比和分析

摄像机标定是立体视觉三维重构的基础,标定的精度、稳定性和效率决定着整个双目立体视觉系统的性能。通过改变标定板图像数目开展标定实验,分别获得了摄像机内参和外参、标定所需时间,分析了标定板图像数目与标定精度和标定效率之间的关系。实验结果表明,对双目立体视觉而言,标定板图像数目为10幅为宜。     

Calibration of an electron back-scattering pattern set-up

The determination of lattice orientations from electron back-scattering patterns (EBSPs) in a scanning electron microscope (SEM) requires accurate knowledge of the position of the pattern centre and the source point to screen distance. This paper outlines a new procedure that enables the determination of these parameters for any given set-up of the EBSP/SEM system. The calibration procedure simply requires the positions and indices of at least four poles in a pattern obtained from an arbitrary specimen, and eliminates the need for standard specimens or special attachments to the EBSP/SEM system. The pattern centre is shown to be located with a precision of approximately 0·5° and the source point to screen distance can be determined with a relative precision of approximately 0·5%.     

Measurement and verification of transient injection flow rate of high pressure natural gas pulse injector

A high-pressure natural gas direct injection engine can achieve lean combustion and diffusion combustion of natural gas, which can reduce the emission level and improve power performance. However, the transient gas injection rate of the injector directly affects the combustion rate. In order to optimize engine performance, it is essential to focus on the technology used to measure the transient injection rate. Therefore, in this study, a method is developed to measure the transient flow rate of a high-pressure natural gas pulse injector. First, experiments were conducted to locate the optimum position for sensor installation, thereby ensuring the quality of the signal. Subsequently, a mass flow meter and schlieren imaging method was used to verify the injection mass and injection start/end timing. Finally, the common working conditions of a certain type of injector are measured. Results indicated that the test error of the cycle injection mass and injection start/end timing did not exceed 4% and 2.1%, respectively. As the injector energizing time increased, the injection rate curve changed from triangle to trapezoid. As the injection pressure increased, the injection start delay time decreased and end delay time increased. Measurement of the main and post injection strategy indicates that the main injection has a significant impact on the injection mass and injection rate curve for post injection. When the interval between the two injections is short, the injection rate curves merge. This increases the injection duration. The total injection mass of the main injection and post injection mass is found to be significantly higher than the sum of the two independent injections.     

Test verification of an extensometer for deformation measurement of high temperature straight pipes

In order to measure deformations of high temperature pipes, an extensometer is designed and verified by experiments. Firstly, the structure and working principle of the extensometer are described. Then experiments both in the laboratory and on site are carried out to prove stability and accuracy of the extensometer. Results from experiments are compared with the calibrating values, and they are in good agreement. The operating condition of the main steam pipe is evaluated by the on-site test. Conclusions can be drawn that the designed extensometer has reliable stability and high accuracy and can be used for measuring deformations of high temperature pipes in power plants.     

A Current Integrator for an Electrostatic Accelerator Energy Scale Calibration System

A circuit diagram of the current integrator intended for the measurements of a positive particle-beam charge arriving at a target is described. The device converts the charge into a number of pulses (target current into the pulse repetition rate). The conversion factor is 10⁹ pulses/C (10⁹ Hz/A), the error is no more than ±1%, the dead time is absent, the input impedance is close to zero, and the temperature drift is no more than 1.2 × 10^–12 /°.     

Calibration of an articulated CMM using stochastic approximations

A coordinate measuring machine (CMM) is meant to digitise the spatial locations of points and feed the resulting measurements to a CAD system for storing and processing. For reliable utilisation of a CMM, a calibration procedure is often undertaken to eliminate the inaccuracies which result from manufacturing, assembly and installation errors. In this paper, an Immersion digitizer coordinate measuring machine has been calibrated using an accurately manufactured master cuboid fixture. This CMM has been designed as an articulated manipulator to enhance its dexterity and versatility. As such, the calibration problem is tackled with the aid of a kinematic model similar to those employed for the analysis of serial robots. In addition, a stochastic-based optimisation technique is used to identify the parameters of the kinematic model in order for the accurate performance to be achieved. The experimental results demonstrate the effectiveness of this method, whereby the measuring accuracy has been improved considerably.     

汽车衡检定的移动式设备

挂码校秤是一种校准电子皮带秤比较简单实用的方法.但在实际操作过程中,由于皮带秤的秤体结构不同,同样重量的砝码即使放置的方法和位置相同,对秤体的作用效果却不同.本文介绍几种秤架结构在进行挂码校秤时的计算方法.     

相移器平移误差与倾斜误差不敏感相移新算法

相移器的相移误差包括平移误差与倾斜误差,使同一幅干涉图诸像素点的相移量并不相等,但仍然在同一平面上.据此,本文提出了消除相移器位移误差与倾斜误差的最小二乘迭代算法.通过对相移平面的最小二乘拟合,即可以消除相移器平移误差与倾斜误差对位相分布求解结果的影响.并通过数值模拟,验证了这种算法在消除相移器位移误差与倾斜影响上的有效性.     

压力传感器动态性能分析与动态补偿

在对炮口冲击波测试中，压力传感器的动态性能指标是否满足测量要求至关重要。本文通过GLS(SF)方法建立压力传感器的数学模型，并由数学模型求出动态性能指标。然而该传感器的动态性能指标不能满足测量要求，针对此问题本文采用零极点相消的方法设计出动态补偿滤波器，明显提高了该传感器的动态性能，最终解决了该冲击波的测量问题。     

一种改进的微控制器FPGA原型芯片设计与验证

HGD08R01是一款与PIC16C57兼容的八位微控制器.本文通过增加在线编程特点,对原有芯片加以改进.为了验证改进后芯片的功能,使用FPGA原型验证方法.首先用完备指令测试方式验证,然后用一个具体的应用--万年历系统来验证原型芯片的功能.实验结果表明,完备指令测试方式的代码全局覆盖率达100%,分支覆盖率达99.51%,在线编程功能达到预期效果;应用系统测试中,万年历能正确稳定工作.     

塑性测压法试样的标定装置及其校准技术研究

提出了一种在塑性测压中对铜柱(球)施加准确力及对加载装置进行校准的新技术方法,它采用加载和平衡双杠杆工作系统,利用可变位置的移动砝码,通过微机自动控制砝码的位置实现自动精密加载.建立了力学模型,进行了理论分析,设计制造了加载装置,并进行了铜柱试样加载、传感器检测等实验研究.论述了自动加载过程中平衡与校准的技术方法问题.新技术方法精度高,可达0.01级;效率高,约20s/级;零点自然平衡;传感器安装位置不敏感;可实现自我校准;工作可靠、数据可信,基本免维护;操作简单.     

新型流速仪检定系统改进方案设计

流速仪检定系统是衡量流速仪测量流速精度的检定装置。针对我国东部水文仪器检测中心的流速仪检定系统运行中出现的薄弱环节,对其低速调速系统、核心控制板抗干扰等部分进行分析研究,提出了改进设计方案,以期达到长期稳定可靠的工作。     

机械式温湿度表的检定调试方法

从机械式温、湿度表的检定操作入手,详细介绍了机械式温、湿度表在检定过程中其温、湿度的调试以及其不确定度的评定方法.