计量科学与技术

Uncertainty Evaluation of the Determination of Gross Alpha and Gross Beta Radioactivity in Drinking Water

GU Xinyi, GU Jun, CHENG Xiaohong

, Available online , doi: 10.12338/j.issn.2096-9015.2023.0277

Abstract(300)

HTML (131)

PDF(43)

Abstract:
This study evaluates the uncertainty in the determination of gross alpha and gross beta radioactivity in drinking water using the thick source method. Following the GB/T 5750.13-2023 "Standard Examination Methods for Drinking Water Part 13: Radioactivity Index," gross alpha and gross beta radioactivity in drinking water were measured. The measurement repeatability was considered as type A uncertainty, while factors such as count rate, residue mass, water sample volume, instrument detection efficiency, and recovery rate were considered as type B uncertainties. The measured concentrations of gross alpha and gross beta radioactivity were 0.66 Bq/L and 0.48 Bq/L, respectively, with relative combined standard uncertainties of 6.0% and 5.7%, and expanded uncertainties of 0.08 Bq/L and 0.06 Bq/L. The uncertainty introduced by the instrument's count rate (n) was the largest source of uncertainty and had the greatest influence. Measurement repeatability, the counting efficiency (ε) of the standard powder source, and the recovery rate of radioactivity (F) also had a significant impact. The total mass of the water sample residue (W), the mass of the residue used to prepare the sample source (m), and the volume (V) of the water sample had less influence.

Research and Implementation of a Fully Intelligent Pressure Gauge Calibration System

DENG Yulan, LIN Feizhen, LIN Yanbo, SUN Tao, HUANG Feng

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0233

Abstract(82)

HTML (54)

PDF(5)

Abstract:
To enhance the efficiency of pressure gauge calibration and reduce reading errors, a fully intelligent pressure gauge calibration system has been developed. The system consists of an integrated AI recognition model, control software, and calibration devices, achieving full automation and intelligence in the pressure gauge calibration process. The system's recognition model is based on a deep learning network framework, integrating the YOLO detection model, Paddle OCR model, text classifier, and adjacent angle reading algorithm. This model can not only identify the pointer readings from pressure gauge images but also capture essential information such as manufacturer, serial number, accuracy class, and units. The control software is designed with a multi-threaded and asynchronous communication structure, supporting communication with multiple hardware components of the calibration device and enabling the simultaneous calibration of multiple pressure gauges. It also allows for the storage of calibration images and data for review and traceability and supports the automatic synchronization of calibration results with the OA system, along with automatic certificate printing. Experimental validation demonstrates that the system can accurately and reliably calibrate 1–6 pressure gauges simultaneously. Compared with manual calibration and other automated systems, this system offers a higher degree of intelligence, greater efficiency, and reduced reading errors, with promising applications and promotion value.

Exploration of Ground Verification for the Adaptability of Metrology Standards in Space

CHEN Aqin, LIU Min, DING Wei, JIN Haibin, WANG Wei

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0172

Abstract(66)

HTML (46)

PDF(1)

Abstract:
Space metrology is a technical and management activity that ensures the uniformity, accuracy, and reliability of measurement units in outer space. Focusing on space metrology, this study selected standard resistors and voltage references as research subjects, exploring a ground test hardware platform for space application electrical standards. A ground verification test platform was designed, and through measurement uncertainty analysis, it was determined that the measurement uncertainty could reach the 10^-5 level, laying a foundation for addressing spatial metrology requirements. However, this system has only been verified for a certain range of physical resistors and specific voltage values. Further research is required to develop ground verification systems for other electrical standards.

Development and Application of an On-Line Micro Gas Chromatograph with Thermal Conductivity Detector for Natural Gas Energy Metering

LIN Junjie, DENG Fanfeng, ZHOU Li, XU Xiangdong, LI Zhiang, ZHANG Ting, XIAO Lian, WEI Dong, PAN Yi

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0078

Abstract(82)

HTML (60)

PDF(2)

Abstract:
The micro gas chromatograph for natural gas energy metering has long been monopolized by foreign companies, creating disadvantages for China in international natural gas trade. Developing domestic alternatives is therefore of great significance. This study developed several key components for natural gas energy metering, including a micro chromatographic injection system, micro thermal conductivity detector (μ-TCD), and an online chromatographic workstation for energy value calculation. The research team has led the development of a highly reliable micro on-line gas chromatograph for natural gas energy metering with independent intellectual property rights in China. The experimental prototype has been successfully applied at natural gas flow metering stations and hydrogen production sites, analyzing 11 components in natural gas such as N₂, CO₂, and C₁–C₆ with an analysis cycle of 2.5 minutes. The detection limit for hexane is 80 μmol/mol, the resolution (R) between n-butane and isobutane is 2.0, the repeatability for n-butane quantification is 0.30%, and the 4-hour instrument stability test shows a deviation of 0.07%. The prototype has passed long-term stability testing of 6020 operating hours, meeting the requirements for natural gas energy metering. This domestically developed micro gas chromatograph represents a significant step toward replacing foreign models, providing crucial measurement technology support for national energy security and the achievement of China's "dual carbon" strategic goals.

Research on Calibration System for Gas Detection Alarms Based on MCGS

CHENG Liping, ZHAO Jinshuang, LI Jian, HE Yuanyuan, XUE Yanming, WANG Haiyan

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0074

Abstract(80)

HTML (32)

PDF(5)

Abstract:
Most continuous on-line gas detection alarms output 4–20 mA analog electrical signals. These devices involve complex gas types, numerous manufacturers, a wide variety of specifications and models, and require intricate wiring operations during calibration. Currently, no calibration system can efficiently handle the calibration of various alarms with 4–20 mA analog signal outputs, resulting in low calibration efficiency. This paper presents a calibration system based on embedded configuration software (MCGS), which offers universality and can automatically collect, intelligently process, and judge the results of multiple gas detection alarm signals simultaneously. Experimental results show that the electrical signals collected by the calibration system are accurate and reliable. During the ventilation test, the indication errors among the channels were relatively consistent, and the overall trend of the indication error was aligned between the system's automatic calculations and the data obtained from the national verification regulation's prescribed method. The system's automatic calculation function significantly improves the calibration efficiency of gas detection alarms.

Accuracy Analysis of Ultrasonic Flowmeter for Sewage Based on Fluent DPM Model

SONG Chao, CAI Lizhi, LIU Hongbin

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0200

Abstract(63)

HTML (37)

PDF(11)

Abstract:
In order to solve the problem of ultrasonic attenuation caused by the upstream elbow disturbing the flow field and the particle impurities in the sewage, simulation calculations were performed based on the Fluent Discrete Phase Model (DPM) bidirectional coupling model. When the pollutant concentration was 1%, four calcium carbonate impurities of different diameters were set. In the sewage with impurities of different diameters, the flow coefficient k value gradually decreased with the increase of the flow point, but at the small flow point of 20m3/h, the maximum influence of 80 large particle impurities on the coefficient k exceeded 5%, and the flow rate was not enough to keep the larger particles suspended in the fluid, resulting in uneven distribution of particle concentration in the flow field and large fluctuations in the speed of the ultrasonic wave on the propagation path. It was found in the pressure cloud map that with the increase of particle diameter, the fluid velocity pressure gradient on the pipe section changed greatly, resulting in violent fluctuations in the flow field, which in turn affected the change in speed on the ultrasonic wave propagation path and caused errors in the flowmeter. In order to reduce the turbulent pulsation caused by large particle impurities in the downstream, a rectifier was set at the bend, and the Laws rectifier physical model was established using Solidworks. The study found that the downstream flow field was more uniform and the velocity gradient changed less, reducing the influence of the backflow vortex on the ultrasonic wave on the transmission path. It has guiding significance for improving the uniformity of downstream flow field and improving the measurement accuracy of ultrasonic flowmeter in sewage.

Experimental Study of Wall Shear Stress Based on Double-Layer Hot Film

FU Zhengwei, ZHAO Longhui, ZHANG Qi, YANG Shuiwang, JIANG Yuxuan, CHEN Xiaoting

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0242

Abstract(182)

HTML (53)

PDF(2)

Abstract:
Wall shear stress is a direct parameter used to accurately study the frictional resistance of fluid flow over a solid wall and is a key factor in evaluating the performance of aircraft equipment and surface friction distribution. Accurate measurement of wall shear stress is crucial for determining the viscous resistance of aircraft and optimizing their structure. This study focuses on verifying a wall shear stress measurement method based on double-layer hot film technology. A long circular pipeline air flow test platform was designed to verify the accuracy of the method in measuring wall shear stress. Additionally, the stability and repeatability of the double-layer hot film sensor for measuring wall shear stress under different temperature differences were evaluated. At ΔT = 30℃, 40℃, 50℃, and 60℃, the maximum measured wall shear stress was 1.27 Pa. The relative synthetic uncertainty of the wall shear stress measurement was 0.50%, and the relative error was less than 4%. The results demonstrate the reliability of the method and its applicability for the precise measurement of wall shear stress.

Research on the Spatio-Temporal Distribution and Influencing Factors of Carbon Emissions in China's Power Industry

LEI Shaobo, TONG Chenhua, XIAO Bin, FAN Haoyan

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0170

Abstract(91)

HTML (46)

PDF(4)

Abstract:
In 2020, China proposed the goals of carbon peaking and carbon neutrality. As a key industry, the carbon emissions of the power sector play a crucial role in achieving these objectives. This study analyzes the characteristics and influencing factors of carbon emissions in China’s power industry by applying traditional statistical methods to the spatio-temporal data of carbon emissions and utilizing grey correlation analysis to assess the impact of different energy sources on carbon emissions in the sector. Temporally, carbon emissions in China's power industry have been rising annually, with fluctuating growth rates. Spatially, the Bohai Rim region consistently exhibits high carbon emissions, while regions like Inner Mongolia and Xinjiang show an upward trend, and the Jiangsu-Zhejiang-Shanghai region shows a downward trend. The grey correlation analysis results indicate that carbon emissions from raw coal, other petroleum products, coke oven gas, and other natural gas have a significant influence on the overall carbon emissions of the power industry.

Research on Calibration Reagents for Isothermal PCR Analyzers Based on Loop-mediated Isothermal Amplification (LAMP) Technology

CHEN Xian, WU Xiao, WANG Zhidong, GAO Yunhua

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0203

Abstract(38)

HTML (31)

PDF(4)

Abstract:
To address the growing demand for accurate calibration of isothermal polymerase chain reaction (PCR) analyzers in the market, this study developed calibration reagents and a standard system for isothermal PCR analyzers based on loop-mediated isothermal amplification (LAMP) technology. Using the specific values and characteristic sequences from fluorescence quantitative PCR instrument standard materials (GBW(E)091100-091108) as the reference, LAMP regular primers (F3, B3, FIP, BIP) and loop primers (LF, LB) were designed. The optimal regular and loop primers, along with the ideal reaction temperature, were identified through screening tests. The performance of the calibration kit was assessed by evaluating the concentration gradient range of the corresponding standard materials, as well as the kit's sensitivity and reproducibility. Calibration reagent performance was further validated using commercially available isothermal PCR analyzers. Results indicated that the optimal reaction temperature for the LAMP calibration kit is 65℃, with the standard material concentration range covering seven orders of magnitude (10⁰ to 10⁶ copies/μL) and a sensitivity threshold of 10⁰ copies/μL. The kit also demonstrated excellent repeatability. The developed LAMP-based calibration reagents are suitable for the calibration of isothermal PCR analyzers, supporting their performance evaluation and market regulation. This research lays a solid foundation for the development and implementation of national calibration and verification standards for isothermal PCR analyzers.

Research on the Calibration Method of PM_2.5/PM₁₀ Particle Automatic Monitoring Instruments Based on Gravimetric Method

ZHANG Wenge, LIU Wei, ZHAO Liang, CHEN Jinchang, ZHOU Huanhuan

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0179

Abstract(70)

HTML (48)

PDF(8)

Abstract:
To ensure the accuracy and reliability of PM_2.5/PM₁₀ monitoring data, this study investigates the traceability method for automatic PM_2.5/PM₁₀ particle monitoring instruments based on the gravimetric method. By analyzing the structure and working principles of these instruments, key parameters and technologies that influence measurement accuracy and are common to such instruments were identified. The study introduces the functions, parameters, and influencing factors of key modules such as the sampling unit, constant temperature and humidity module, weighing module, and filter membrane electrostatic removal module. Calibration methods were developed, and corresponding measurement performance parameters were extracted, along with specified indicator values. Through extensive experiments, using widely adopted monitoring instruments, the rationality of the performance parameter indicators and the feasibility of the testing methods were verified. Furthermore, the uncertainty evaluation method for calibration results was provided based on an analysis of the factors affecting the calibration process. This study lays the groundwork for the development of relevant technical standards and ensures the accuracy and validity of calibration data for these instruments.

A High-Accuracy Direction of Arrival Measurement Method for Millimeter-Wave Radar Based on a Fast Iterative Adaptive Algorithm

YU Danyang, DU Lei

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0198

Abstract(142)

HTML (33)

PDF(25)

Abstract:
The Iterative Adaptive Algorithm (IAA) is a super-resolution algorithm widely applied for high-accuracy direction of arrival (DOA) measurements in millimeter-wave radar systems. However, traditional IAA faces challenges such as algorithmic complexity and computational delays, rendering it unsuitable for real-time applications. Additionally, to mitigate angle estimation errors caused by mismatches between the source locations and the grid dictionary, grid refinement is commonly employed, further exacerbating the slow computational performance of the IAA. To address these issues, this paper proposes a Fast Iterative Adaptive Algorithm (FIAA). The FIAA utilizes a hierarchical grid refinement approach to iteratively estimate source angles. Initially, a coarse grid is applied over the entire spatial domain, identifying potential areas of the actual source locations using IAA. Subsequently, in these identified regions, a refined grid division is applied, and the signal direction matrix is updated. Finally, the IAA, incorporating a regularized covariance matrix, is utilized to achieve high-accuracy angle measurements. Experimental results show that FIAA effectively avoids scanning and computations in non-signal regions, reducing computational time to as little as 4% of the IAA, while maintaining comparable accuracy when the signal-to-noise ratio (SNR) exceeds 0dB. This approach is well-suited for high real-time and high-accuracy millimeter-wave radar DOA measurement scenarios.

Research on the Verification Method of Vehicle Horn Monitoring System

TANG Jiahao, ZHOU Changhua, LI Lin

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0165

Abstract(89)

HTML (39)

PDF(3)

Abstract:
As an off-site law enforcement system, the vehicle horn monitoring system is an effective tool for traffic police to monitor and penalize illegal vehicle horn usage. This study focuses on the verification methods for such systems, particularly analyzing the sound source localization algorithm principles. It investigates the key verification items listed in the national verification regulations, including measurement error of sound pressure level, spatial resolution, positioning error, effective identification area, and the time consistency of acousto-optic images. By analyzing the localization results of sound sources at different frequencies and positions, the study identifies patterns relevant to vehicle horn monitoring systems. The results show that sound pressure level measurements should be conducted in an anechoic chamber to minimize unnecessary sound reflections. Additionally, there is an inverse relationship between spatial resolution and resolution angle at different frequencies. Positioning error is more pronounced in the Y-axis direction due to greater distance attenuation effects, resulting in larger errors compared to the X-axis direction.

Evaluation of Uncertainty in Resistance Measurement for Verificating Meter for pH Meters Based on MCM

LI Xiang

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0197

Abstract(44)

HTML (28)

PDF(2)

Abstract:
The Verificating meter for pH meters serves as a metrological standard device for the verification and calibration of the electrical meter parts of instruments such as pH meters,ion meters,and automatic potentiometric titrators. It plays an important role in the field of electrochemical metrology.With the release of JJG 919-2023 "Verification Regulation of Verificating Meters for pH Meters",there has been no provision of content regarding the uncertainty of resistance measurement results of high-resistance devices in Verificating meters for pH meters.This article evaluates the uncertainty of resistance measurement results of high-resistance devices in Verificating meters for pH meters by applying the internationally recognized uncertainty evaluation methods:the Guide to the Expression of Uncertainty in Measurement(GUM) method and the Monte Carlo Method(MCM).Initially,we use the GUM method to assess the measurement uncertainty of high-resistance values,adopting MCM alchimia software to evaluate the uncertainty of its measurement results through the MCM method.To verify the effectiveness of MCM alchimia software for the MCM method,a comparison of the calculation results of the MCM method and the adaptive MCM method using MATLAB software with more comprehensive computation and visualization capabilities is conducted.The results indicate that the uncertainty outcomes calculated by MCM alchimia software are consistent with those obtained through MATLAB programming.Additionally, by employing the MCM method to validate the GUM method results as described in JJF1059.2-2012,the applicability of the GUM method for evaluating the uncertainty of resistance measurement results of high-resistance devices in Verificating meters for pH meters was assessed and failed to pass the validation.Therefore, applying the MCM method and utilizing MCM alchimia software provides a reference for the standardization of uncertainty assessment methods in resistance measurements of high-resistance devices in Verificating meters for pH meters.

Detection and Standardization of Homovanillic Acid and Vanillylmandelic Acid

YU Lintao, CHENG Long, KANG Shiyue, ZHANG Qiaoxuan, HAN Liqiao, ZHAN Min, ZHANG Pengwei, YAN Jun

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0136

Abstract(78)

HTML (83)

PDF(8)

Abstract:
Homovanillic acid (HVA) and vanillylmandelic acid (VMA) are end metabolites of catecholamines. Measurement of HVA and VMA in urine not only serves as an indirect indicator of catecholamine secretion in the body but also holds significant importance in the early diagnosis and differential diagnosis of central nervous system diseases such as neuroblastoma and pheochromocytoma. Although various methods for detecting HVA and VMA are available, significant discrepancies exist in the results obtained from the same sample when tested within or across different institutions. Therefore, establishing reference methods and reference systems to ensure the accuracy and comparability of HVA and VMA measurement results, as well as traceability and standardization of testing, has become a new goal and challenge in the field of clinical detection. This article reviews the clinical significance, detection methods, and current status of standardization of HVA and VMA testing.

Development and Application of Automatic Ultraviolet Oil Measuring Instrument

GUO Bo, ZHOU Li, ZHANG Sen, LIU Chuanrong, SUI Feng, YANG Zhongyuan

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0205

Abstract(80)

HTML (37)

PDF(1)

Abstract:
Based on the testing requirements of the national environmental protection standard HJ 970-2018 “Water quality- Determination of petroleum-Ultraviolet spectrophotometric method”, the principle of UV oil spectrophotometer was analysed. Then, a new type of automatic ultraviolet oil measuring instrument was developed by means of automatic and integrated design of injection system, extraction system, adsorption system and detection system. The structure, principle, application and maintenance of the instrument were introduced emphatically. In addition, the instrument was calibrated according to JJF (Min) 1141-2023 “Calibration Specification for Oil Content Analyzers of Ultraviolet”. In the range of (0.0～16.0) mg/L, the linearity was 0.9999. When the measured value was not more than 2 mg/L, taking 1.0 mg/L as example, the indication error was −0.042 mg/L. When the measured value was more than 2 mg/L, taking 4.0 mg/L, 8.0 mg/L and 16.0 mg/L as examples, the indication error were −3.6% , −2.2% and −1.7%, respectively. In addition, the items of instrument repeatability, minimum detectable concentration, zero drift and indication drift were calibrated. Through the above calibration experiments verified that the performance of the instrument was excellent. By using the automatic ultraviolet oil measuring instrument, the environmental protection workers could reduce the working intensity, improve the working efficiency, reduce the organic hazards, and ensure the accuracy and efficiency of the environmental monitoring work.

Application of Osmotic Coefficient Theory of Electrolyte in Metrology of Physical Chemistry Quantities Including Water Activity

WANG Haifeng, LI Jia

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0191

Abstract(113)

HTML (67)

PDF(1)

Abstract:
Osmotic coefficient (ϕ) is a measure of the deviation of the solvent of electrolyte from the ideal solution. ϕ was usually determined by the manometric method and the electromotive force method. National bureau of standard of United States of America published the reference value of osmotic coefficient equal to the average of many scientific data and its standard deviation based on the statistics. This reference data was expressed as the Debye-Hückel equation. When the molality of the electrolyte was introduced in the equation, and thus the corresponding osmotic coefficient was deduced. ϕ can be used to calculate the water activity, freezing point depression and osmotic pressure concentration of the solution of electrolyte, and thus the reference solution of these quantities were determined and then used to calibrate the instrument of these quantities. Sodium chloride was the most commonly used electrolyte. The reference values specified by the related international or national standard were well consistent with the results calculated using the reference data of ϕ. The reference values of related physical chemistry quantities calculated using the reference data of ϕ were traceable to SI units of vapor pressure or potential of the electromotive force indirectly.

Effect of paddy varieties on the measurement accuracy of capacitive grain moisture tester

CUI Tiyun, SHEN Taotao, WU Xin, LIU Yuming, ZHANG Wendong

, Available online , doi: 10.12338/j.issn.2096-9015.2024.0106

Abstract(89)

HTML (40)

PDF(4)

Abstract:
As an instrument to measure grain moisture rapidly, capacitive grain moisture tester is widely used in grain trade settlement, and it is one of the measuring instruments under compulsory management of the state. The measurement accuracy of paddy moisture content based on the principle of capacitive method is affected by many factors. In this paper, the influence factors of paddy varieties are studied and analyzed. The moisture content of 7 different varieties of paddy was measured by 3 capacitive grain moisture testers at two moisture points of about 11.5% and 16.5% respectively. The results show that the paddy varieties have significant influence on the measurement accuracy of the capacitive grain moisture tester, and it is not advisable to use the same moisture tester to measure the water content of different varieties of paddy.

Determination and Uncertainty Assessment of Lactic Acid in Serum

ZHU Tianyi, DING Min, DUAN Manlei, MENG Jiaoran

, Available online , doi: 10.12338/j.issn.2096-9015.2023.0353

Abstract(286)

HTML (79)

PDF(15)

Abstract:
An isotope dilution-gas chromatography-mass spectrometry method for the determination of lactic acid concentration in serum was established, and the uncertainty of the measurement results was evaluated. Sodium lactate isotope label was added to the serum sample as internal standard. After pretreatment and silanization derivatization, samples were detected by gas chromatography-tandem mass spectrometry in selected ion monitoring mode. The established quantitative analysis method was used to analyze five different concentrations of lactic acid in serum. The results showed that the method had good linearity, and the correlation coefficient was r>0.999. The average spike recovery rate was 101.2%～102.6%, and the relative standard deviation was 0.16%～0.59 % (n = 6). The concentration of lactic acid in five different serum was 1.16 mmol/L, 2.01 mmol/L, 5.50 mmol/L, 10.02 mmol/L, and 15.63 mmol/L, and the related expanded uncertainty U_rel of the results was less than 3.0% (k = 2). The method had good repeatability, high accuracy, reliable results, which could be used for accurate detection of lactic acid concentration in clinical serum sample.

Online First

DynamicMORE+

ScienceMORE+