计量科学与技术

Rapid Analysis Method for Benzene Series, Methane, and Total Hydrocarbons in Ambient Air

DENG Wenqing, DENG Fanfeng, ZHANG Ting, XU Bingyan, XIONG Huajing, PAN Yi

2024, 68(7): 3-9. doi: 10.12338/j.issn.2096-9015.2024.0037

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Fugitive emissions of benzene series compounds and total hydrocarbons pose irreversible harm to the ecological environment and human health. The rapid and accurate analysis of these compounds has long been a research focus in ambient air monitoring. A quick method for the analysis of total hydrocarbons, methane, benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene, and styrene was developed using a multi-dimensional gas chromatograph with dual FID detectors. The results show that the target components can be accurately analyzed within 12 minutes with a single injection, and the components exhibit good linearity and repeatability across the measurement range. This method demonstrates excellent detection limits, with accuracy ranging from −7.7% to 0.2%. The method can be applied for on-line calibration of analytical instruments in various spatiotemporal scenarios, showing potential application value in field mobile monitoring of ambient air.

Study on the Impact of Multicollinearity Among Components on Near-Infrared Spectroscopy Quantitative Models

TIAN Lu, XU Dongqing, SU Wending, ZHANG Mengsha1, LI Yankun

2024, 68(7): 10-16. doi: 10.12338/j.issn.2096-9015.2024.0014

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In quantitative analysis using near-infrared spectroscopy combined with chemometric methods, multicollinearity among variables is a key issue affecting the performance of spectral models. This study investigates the impact of multicollinearity between component concentrations on chemometric quantitative models. Two systems were designed with strong and weak correlations between the concentrations of vitamin B6 (low concentration) and vitamin B1 (high concentration), respectively. Using vitamin B6 as the target component, prediction models for component concentrations were established using near-infrared spectral information combined with partial least squares regression. The results show that when there are coexisting components with high concentrations strongly correlated to the target component in the system, the model can utilize information from these coexisting components to achieve more accurate predictions of the lower-concentration target component, thereby improving the precision of quantitative analysis for the target component. The application of this approach to the detection of commercially available oral solutions containing vitamins B6 and B1 further verified that strong multicollinearity between component concentrations can enhance the quantitative predictive ability of near-infrared spectral models. The conclusions of this study have significant theoretical and practical application value and can be applied to the simultaneous quantitative analysis of components in complex mixture systems.

Research on Valuation Method and Uncertainty Evaluation for Milk Somatic Cell Count Reference Materials

LIU Yingying, ZHOU Yuhu, WANG Ziquan

2024, 68(7): 17-22, 48. doi: 10.12338/j.issn.2096-9015.2024.0018

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A method based on microscopic imaging flow cytometry was established to measure the concentration of milk somatic cells in reference materials for milk somatic cell count. This method labels milk somatic cells using the fluorescent dye ethidium bromide. The single-cell multi-parameter microscopic images provided by microscopic imaging flow cytometry can effectively assist in identifying target cells in flow cytometric analysis, thereby improving the accuracy and repeatability of gating strategies. Through multiple measurements and analyses of milk somatic cell reference material samples with different somatic cell concentrations, it has been proven that this method has good intra-laboratory and inter-day repeatability. A mathematical model for measuring the concentration of milk somatic cells in reference materials for milk somatic cell count based on microscopic imaging flow cytometry was established. The analysis determined that the main sources of uncertainty in this measurement method come from measurement repeatability, sample pretreatment, reagent addition, gating operation, and instrument measurement volume deviation. Comprehensive evaluation targeting the candidate Grade V (～1.0×10⁶ cells/mL) reference material for milk somatic cell count prepared in this study shows that the relative uncertainty of the measurement method for milk somatic cell concentration based on microscopic imaging flow cytometry is 4.84%.

Discussion on Digital Metrology Method for Protocol-based On-board OBD Acquisition Terminal

ZHANG Hongbao, JIANG Kun, MA Ming, LU Jiawei, ZHENG Xiaoxiao

2024, 68(7): 23-27. doi: 10.12338/j.issn.2096-9015.2024.0003

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To ensure the accuracy and reliability of on-board OBD (On-Board Diagnostics) acquisition terminals and improve the effectiveness of exhaust emission monitoring and overstandard screening for heavy-duty diesel vehicles, a digital metrology method is proposed. This paper introduces the definition, application, and current metrological status of on-board OBD acquisition terminals. It elaborates on the calibration method for these terminals and demonstrates their metrological characteristics from two aspects: determination of maximum permissible error and uncertainty evaluation. Three conclusions are drawn from the demonstration: the maximum permissible error of real-time engine data flow from the calibration device is set according to the data flow precision specified in the protocol, and the maximum tolerance of the on-board OBD acquisition terminal is set at twice the tolerance of the calibration device; the uncertainty introduced by the real-time engine data flow from the calibration device is $U_{\mathrm{rel}} =1 \times 10^{-6} $, $ k=\sqrt 3 $, and the uncertainty evaluation of the on-board OBD acquisition terminal meets the quantity transfer requirement of $U\le \mathrm{M}\mathrm{P}\mathrm{E}\mathrm{V}/3 $; test results show that the indication error of the on-board OBD acquisition terminal does not exceed the maximum permissible error, the metrological performance requirements are reasonable, and the calibration method is highly operable.

Gaussian Filtering Algorithm and LabVIEW Software Design for Non-Contact Measurement of Surface Roughness

CHEN Ting, WU Chunhui, LU Xin, WANG Yinghui, YE Huaichu, CHEN Ning, GUO Gangxiang

2024, 68(7): 28-34. doi: 10.12338/j.issn.2096-9015.2024.0032

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This study investigates the adaptability of the Gaussian filtering method in non-contact measurement of surface roughness. Using surface profile data obtained from a spectral confocal displacement sensor as an example, the Gaussian filtering algorithm is introduced to compute the filtering centerline and separate the roughness signal. A program for the Gaussian filtering algorithm is designed on the LabVIEW platform, calculating the roughness values and comparing them with the results of current contact calibration. Experimental results indicate that the Maximum Permissible Error (MPE) of the R_a value after non-contact data processing is ±5%, demonstrating that the Gaussian filtering method is suitable for data processing in non-contact measurements. The modular design of the algorithm in LabVIEW is easy to implement, integrates well with other modules, is easy to maintain, and holds significant potential for wider application.

Research on Calibration Method and Device for Ultrasonic String Phantoms Based on Intelligent Technology

QI Fang, WANG Tongyu, LIU Zhe, ZHU Weimin

2024, 68(7): 35-40. doi: 10.12338/j.issn.2096-9015.2023.0350

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This study investigates the calibration method for ultrasonic Doppler string phantoms and presents the design and development of a calibration device based on intelligent technology. The device employs a dual-channel laser velocimeter to collect the rotational speeds of the drive and driven wheels of the ultrasonic string phantom. These data are then input into an analysis system to calculate the string velocity of the phantom. Additionally, the device can collect linear velocities at various points within the physiological waveform cycle and compare them with standard physiological waveform velocities in a database to determine whether the test waveform and physiological waveform curves meet requirements at the set velocity. Experimental results demonstrate that, compared to existing methods for detecting constant blood flow velocity, this method and device not only efficiently detect constant blood flow velocity but also intelligently assess physiological waveforms. This approach effectively addresses the calibration and traceability issues of ultrasonic string phantoms.

Design of a Three-Axis Fiber Optic Gyro Combined Optical Path Detection System

SONG Liyuan, MI Qian

2024, 68(7): 41-48. doi: 10.12338/j.issn.2096-9015.2024.0138

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This paper presents the design of a three-axis fiber optic gyro combined optical path detection system based on a Super Luminescent Diode (SLD) light source. The system employs synchronized temperature control and constant current drive circuits to ensure normal operation of the SLD across the full temperature range. The power supply section incorporates surge protection to effectively prevent transient impacts caused by switching power supplies or environmental changes, thus protecting the components. The detection system monitors the photodetector's output bias voltage under both light and no-light conditions, while simultaneously calculating the assembled optical path system loss through numerical analysis. This approach determines whether the fiber optic gyro's optical path technical specifications meet the design requirements. Finally, experimental validation demonstrates the effectiveness of the three-axis fiber optic gyro combined optical path detection system in batch production processes. The system improved the accuracy stability of fiber optic gyros to 87% and increased the finished product qualification rate to 96%.

Research Progress on Cosmetic Matrix Reference Materials

LI Shuo, LIU Zhe, WU Xue, LI Qingwu, ZHANG Zhengdong, LI Li

2024, 68(7): 49-54. doi: 10.12338/j.issn.2096-9015.2024.0159

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Over the past decade, cosmetic quality and safety issues have increasingly become a focus of consumer concern. Many well-known cosmetic brands have been reported to contain prohibited or restricted substances, not only harming consumer interests and causing economic losses to cosmetic companies but also challenging regulatory agencies and quality inspection institutions. Cosmetic matrix reference materials, due to their similarity to real samples, are widely used in developing and evaluating analytical methods for cosmetics with similar matrices, laboratory proficiency testing, and quality control of qualitative and quantitative analyses. They play an irreplaceable role in ensuring the accuracy, reliability, and traceability of test results, serving as important "measurement instruments" in the analytical field. This article reviews the development of cosmetic matrix reference materials in China from 1993 to the present. Starting from the definition and classification of cosmetics, it analyzes aspects such as the types of target additives, matrix types, and grading of reference materials. Based on the main challenges faced in this field, it anticipates the demand and trends for cosmetic matrix reference materials and proposes solutions to constraints on their development, aiming to provide references for future research on cosmetic matrix reference materials.

Traceability Discussion on China VI Standard Automobile Exhaust Emission Detection

LIU Yiling, LI Xiuli, HAO Jingkun

2024, 68(7): 55-62, 16. doi: 10.12338/j.issn.2096-9015.2024.0058

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As the number of vehicles in China continues to increase, pollution from automobile exhaust has become increasingly severe. To control environmental pollution, China promulgated the "Air Pollution Prevention and Control Law of the People's Republic of China" as early as 1987. In 2013, the European Union released the Euro VI standard (EURO VI A-VI D). China, drawing on the Euro VI standard and considering its national conditions, issued GB 18352.6-2016 "Limits and Measurement Methods for Emissions from Light-Duty Vehicles (China 6)" (hereinafter referred to as the China VI standard) in 2016, which was implemented in phases starting from January 2020. This standard has set new requirements for the regulation and quality control traceability of automobile exhaust emissions. This article compares the differences in emission quality control requirements between the China V and China VI standards, and introduces the measurement methods for updated emission-limited pollutants in the China VI standard, including carbon monoxide (CO), nitrogen oxides (NOx), non-methane hydrocarbons (NMHC), nitrous oxide (N₂O), particle number (PN), and particulate matter (PM). It also describes China's exhaust emission detection and traceability technology from the aspects of developing national gas reference materials, establishing measurement standards, and founding national automobile testing centers. The analysis shows that existing capabilities and technical levels cannot meet some emission detection requirements in the China VI standard. The article proposes areas in current traceability technology that need further optimization, such as the condensation particle counter in particle number (PN) measurement instruments. It points out that research and improvement should be accelerated on metrological indicators like particle concentration attenuation coefficient, volatile particle removal efficiency, and dilution ratio. Regarding the requirements for determining methyl chloroformate and benzo[a]pyrene pollutants specified in the Euro VI standard, China currently lacks corresponding reference materials and traceability systems. It is necessary to develop compliant reference materials and establish traceability standards to prepare for increasingly updated quality control requirements both domestically and internationally. The article also offers suggestions in response to the proposed European seventh stage emission standard (Euro 7).

Uncertainty Evaluation of Piston Gauge Effective Area Using the Monte Carlo Method

WANG Bowen, YANG Yuanchao, YANG Ying, MA Kun, YUE Jin

2024, 68(7): 63-71, 9. doi: 10.12338/j.issn.2096-9015.2024.0013

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Uncertainty evaluation is a crucial component in the dissemination of measurement values. Following the publication of JJF 1059.2-2012 "Evaluation of Measurement Uncertainty Using the Monte Carlo Method," this approach has been increasingly applied across various metrological disciplines. Using Python, calculation codes were developed employing both the Monte Carlo method and the adaptive Monte Carlo method. Taking the calibration of a 100 MPa oil-medium piston gauge as an example, the uncertainty of the calibrated effective area was evaluated. The impact of uncertainties and probability distribution models of various input quantities on the output uncertainty was analyzed and compared with results from traditional evaluation methods. The findings indicate that the primary source of uncertainty in the calibration of the piston's effective area is the uncertainty introduced by the standard piston's effective area. Results obtained using the Monte Carlo method align with those from traditional evaluations, both yielding a relative expanded uncertainty (k=2) of 32 ppm. The probability density distribution of the calibrated effective area is determined by the probability density distribution of the main influencing factors.

Measurement Uncertainty Evaluation of a Leukemia Recognition Algorithm Based on Patient Clinical Data

JIANG Chaofan, YAN Jingting, WANG Tingting, ZHANG Jiatao, CUI Weiqun

2024, 68(7): 72-77. doi: 10.12338/j.issn.2096-9015.2024.0125

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With the advent of the digital age, algorithms increasingly dominate the development of various industries and the emergence of new sectors, giving rise to a digital economy-led industrial landscape. Metrology, as the science of measurement and its application, is rapidly entering the digital era, with the promotion of digital transformation in the metrology industry becoming a top priority. Consequently, evaluating the accuracy and reliability of algorithmic software outputs has become a focal point of current research. This paper employs a digital metrology method based on reference data, using the output of a leukemia recognition algorithm software applied to patient clinical test data as the measurement result. It establishes an evaluation model for the leukemia recognition algorithm, outlines the specific process for assessing measurement uncertainty, and calculates the combined standard uncertainty of the measurand.

2024, 68(7): 78-78.

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2024 Vol. 68, No. 7

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