Abstract: This paper introduces the research on the monoenergetic X-ray calibration device and detector calibration method carried out by the Monoenergetic X-ray Laboratory of NIM. The energy range of the established monoenergetic X-ray calibration device can cover 5～300 keV, which provides the ground calibration of performance indicators such as energy linearity, detection efficiency, position response, and angular response for space-borne detectors of space science satellites in China. Satellite projects being calibrated include spaceborne detectors for scientific satellites such as SVOM, GECAM, and HXI.
Abstract: Inertial technology is the acquisition and perception technology for studying carriers’ motion information such as the position, velocity, and attitude, etc. It has become one of the core signs of national scientific and technological level and national defense strength. With the impetus of the demand from national defense and national economic construction, inertial technology has been highly valued by all countries, which is an essential, strategic, and forefront dual-use high technology. As the core instrument for measuring the angular velocity of carriers in the area of inertial technology, a gyroscope is one of the core information sources to adjust/control the attitude of carriers and realization of autonomous/covert navigation, with the development trend in high precision and miniaturization. This paper summarizes the development of inertial technology, emphasizes the development of gyroscopes and the research of metrology in inertial testing, and looks forward to inertial measurement based at the atomic level in the new SI era.
Abstract: The microscope imaging and image analysis method was commonly used for the size and geometry measurement of spherical particles. As manual processing for particle images were required, the measurement procedure was time-consuming, and extra uncertainties were introduced. To solve this problem, the automatic particle measurement method based on circle fitting aided recognition algorithm was developed. The automatic particle size and geometry analyses were realized by using circle fitting aided single-particle recognition, followed by the optimization of edge recognition. Comparing with the manual method, the automatic method greatly speeds up the image processing procedure with better repeatability.
Abstract: The classical measurement error theory postulates that the measured (observed) value is a random variable while the true value is a constant. In contrast, a new-concept measurement theory postulates that the measured value is a constant while the true value is a random variable. After reviewing concepts in the probability theory, this paper makes a comparative analysis of the above-mentioned theories in respect of the different interpretations of the constant and the random variable. It is pointed out that the traditional measurement theory misinterprets basic mathematical concepts, leading to conceptual or logical trouble. The basic concepts and logic and principles of error evaluation are explained in the new measurement theory.
Abstract: This paper describes the concept and performance evaluation of an NOx monitor with ZrO2 oxygen pumping sensors. Test results showed that the NOx monitor presented good repeatability, accuracy, and stability, and it was seldom affected by the environment. It suggested that the NOx monitor could be used in the continuous monitoring of NOx in exhaust gases produced by industrial processes.
Abstract: The pollution of heavy metal in the atmosphere has been attracting more attention due to its harm to human's health. Online monitoring systems for atmospheric heavy metal based on X-ray fluorescence spectrometry (XRF) and the filter membrane sampling technique are available in the market. They have high measurement efficiency by measuring dozens of heavy metal elements simultaneously and hence have good prospects for application in environmental atmospheric monitoring. However, there is lack of verifications or specifications or standards for measurement of those systems in China. An online monitoring system (AHMA-1000) was tested according to the certification rules established by the China Association of Environmental Protection Industry. A comparison test on actual samples was made by setting up a particulate aerosol generator that generated metal elements particulate aerosol of stable concentrations.
Abstract: This paper introduces the primary type and principles of linear guides and their application in large-scale length measurement. Performance analysis was made on two mainstream types of guide, i.e. the 80-m aerostatic guide at the National Institute of Metrology, China and the 60-m linear motion rolling guide at the National Institute of Measurement and Testing Technology, China, which could shed light on development of standard devices for large-scale length measurement.
Abstract: As toxic and flammable gas alarms are used in safety protection in petroleum, chemical and other product manufacturers, the linearity, reliability and accuracy of their core sensors are important. Taking an electrochemical gas sensor for detecting carbon monoxide as an example, this paper presents its principles and overall working process, describes the function of its each component, and discusses its performance characteristics in various situations. Finally, the evaluation of the linearity, correlation, response time, and temperature and humidity dependence of the sensor is presented.
Abstract: This paper briefly describes the development history and current situation of tank metering techniques as well as the characteristics of each development stage. Disadvantages of traditional tank metering techniques and advantages of new tank metering techniques are presented by comparative analysis, demonstrating the necessity of promoting automatic tank metering techniques. Advantages of online servo densitometers and the feasibility of their application in automatic tank metering are illustrated through application examples. Considering the current situation of various oil depots, this paper identifies some problems in automatic tank metering and makes some suggestions on promoting applications of online densitometers.
Abstract: This paper investigates a verification facility for water meters based on related regulations for water meters and verification of water meters. The minimum water consumption of the verification facility, which adopts a start-stop weighing method, is analyzed. The verification facility was improved by adding an electronic balance.
Abstract: Odor pollution has been rated as the primary concern of environmental supervision. The monitoring of odor pollution by humans is being gradually replaced by instrument online-monitoring in order to implement a policy for urban grid management. However, the multi-compounds of malodorous gas as well as the cross interference restrict the development of odor online-monitoring. This paper introduces a malodorous gas online-monitoring technique based on the ultraviolet difference spectroscopic analysis and the verification of its metrological performance. This odor online-monitoring has a prospect of application in odor supervision in China because of its advantages, including high accuracy, low influence of cross interference and temperature as well as a reasonable price.
Abstract: The quality of nuclear fuel in a pressurized water reactor has a direct bearing on the reactor safety. The fuel rod length is an important indicator in the quality control of nuclear fuel. Its measurement by a manual comparison with standard lengths is gradually replaced by automatic measurement systems. However, a specific and systematic verification and monitoring method for such systems has not yet been developed. This paper proposes a method for verifying an automatic length measurement system for fuel rods based on the investigation of the measurement system. An in-use automatic length measurement system was assessed by using this method.
Abstract: The capacity of a vertical metal tank is usually measured when the tank is empty. If the tank is filled with liquid, the tank body will expand due to the static pressure of the liquid, which will increase the tank capacity. Generally, the static pressure correction value is 0.016%～0.21% of the total volume, which is introduced in capacity tables. For safety of the tank body, one or more reinforcement rings can be installed on the upper part of the tank. The reinforcement rings could affect the correction of liquid static pressure. This paper analyzes the effect of reinforcement rings theoretically and discusses how to calculate the correction of liquid static pressure.
Abstract: The sound pressure source generated by the resonant coupled tube method has a high sound pressure level with a low distortion. It is usually used for the calibration of level linearity and distortion of high sound pressure microphones at a fixed frequency. Based on the acoustic finite element model, this paper analyzes the characteristic frequency and frequency response of a resonant coupled tube, and optimizes the design of the tube. The experimental value of the resonant fundamental frequency differed from the calculated value by 0.8 Hz. The resonant coupled tube at 500 Hz generated a sound pressure level of 174 dB with a total harmonic distortion of 0.5%.
Abstract: This paper proposes an improved design of a standard bell prover in light of shortcomings of traditional ones. The advantages of the design are described based on three innovative concepts. The experimental data from the improved design by using the traditional forward- and backward-blowing methods is given, demonstrating the accuracy of the facility. The connection diagram of the design is also provided. The design is compared with existing techniques.
Abstract: The strain field measurement on the micro/nano scale is one of the most important research topics of experimental mechanics. Most existing research ignored the influences of the speckle image quality, the systematic random error, calculation processes and other factors on the accuracy of strain field measurement. In order to overcome the above challenges, the implementation of the Digital Image Correlation (DIC) technique based on the Scanning Probe Microscope (SPM) was investigated, and scientific evaluation criteria and an improved displacement field calculation method were proposed. Experimental results showed that the estimation performance of the displacement field was significantly enhanced in terms of accuracy control.