During the review process of metrological institution standardization assessments, it was observed that numerous municipal and county-level metrological institutions inadequately considered the influence components of uncertainty in the uncertainty evaluation of gas meter calibration devices. This reflects a lack of in-depth understanding among some laboratory personnel regarding the uncertainty influences of such devices. In particular, older devices, constrained by the technical and economic limitations of their time, are equipped with relatively simple supporting metrological equipment. This inevitably leads to more complex sources of uncertainty, which are often overlooked in practical evaluations. To address this issue, this paper systematically identifies and comprehensively considers various uncertainty influence components, using the uncertainty evaluation of gas meter calibration devices at the Hebei Institute of Metrological Supervision and Inspection as a case study. The aim is to provide a reference for relevant metrological institutions.

This paper conducts research on the key technologies involved in the verification of fuel dispensers. It systematically analyzes the scientific selection methods for metrological standards, with a particular focus on the mechanisms through which temperature affects verification results and corresponding control strategies. The study further elaborates on the full-process operational specifications, encompassing nameplate inspection, interlock function verification, software identification checks, indication error verification, as well as repeatability and payment amount error testing. This work provides technical support for establishing a precise and efficient regulatory system for fuel dispenser metrology.

To solve the problems of low overall work efficiency and easy errors caused by manual operation in the traditional calibration method of constant temperature bath, this aims to develop a fully automatic calibration system to improve the accuracy and reliability of temperature metrology. A system consisting of a mechanical lifting device and an upper computer automatic calibration software is to achieve automatic movement of the thermometer between test positions, data collection, processing and analysis, and automatic generation of original records and certificate reports, thus replacing the traditional manual plugging recording and calculation process. This study has successfully achieved fully automatic calibration of the constant temperature bath, effectively reducing the workload of operators and significantly reducing the error rate in the process of manual and recording. This intelligent device not only ensures the accuracy and reliability of temperature metrology calibration work but also provides feasible technical paths and practical references for the automation upgrade of related met fields.

α and β surface contamination monitors are crucial instruments for radiation safety monitoring, and the accuracy of their values is of paramount importance. In practical verification processes, these monitors often encounter various issues due to factors such as service life, operating environment, and usage conditions, leading to deviations in verification results or interruptions in the verification procedure. Based on statistical analysis of verification data from 2,613 α and β surface contamination monitors, this study found an overall disqualification rate of 8.8%. The primary reason for disqualification was identified as abnormal surface emission rate response, accounting for 66.23% of cases. This paper systematically analyzes the root causes of these problems and proposes a comprehensive set of maintenance recommendations covering whole-lifecycle management, standardized operation, performance maintenance, and personnel training. The aim is to provide references for the industry to enhance instrument management and ensure verification quality.

A binocular structured-light measurement system involves a complex model, multiple error sources, and correlation coefficients that are difficult to determine, making it hard to accurately evaluate its measurement uncertainty using the conventional Guide to the Expression of Uncertainty in Measurement (GUM). To address this issue, an improved GUM method based on grey theory is proposed. First, the grey model GM(0,2) is employed for non-statistical evaluation of Type A uncertainty components, while Type B components are assessed by the traditional approach. Then, grey relational analysis is applied to quantify the correlations among error sources and to determine the corresponding correlation coefficients. Finally, the overall measurement uncertainty is synthesized within the GUM framework. Applied to a binocular structured-light measurement system, the proposed method yields a measurement uncertainty of 0.0934, demonstrating its reliability.

Aiming at the problems of lagging thermal runaway warning and fragmented protection for lithium-ion batteries, this paper reviews the latest research progress of multi-modulus intelligent fusion and hierarchical linkage safety protection system. Firstly, the mechanism of “chain side reaction” of thermal runaway and its multi-physical field evolution characteristics are analyzed. Meanwhile, the sensing boundaries of multi-dimensional sensing technologies such as electrochemistry, temperature, pressure and gas detection are clarified. The core discussion focuses on the mechanism- and data-driven multi-modulus fusion algorithm, which solves the “black box” dilemma of traditional models, as well as the closed-loop of “four-level risk warning” and “five-layer protection architecture”. Research data show that after adopting multi-modulus fusion technology, the warning time can be advanced by more than 30 minutes, and the fault identification accuracy can reach more than 99%, which provides a new approach for the safety management of the full life cycle of lithium-ion batteries.

The insulating oil dielectric strength tester is an instrument for detecting the dielectric strength characteristics of insulating oil, and is used to determine the withstand voltage value or breakdown voltage value of insulating oil. This article introduces several calibration methods for insulating oil dielectric strength testers and elaborates on the relevant advantages of the fully insulated PT measurement method through the comparison of on-site testing data.

To solve the low efficiency of traditional supervision for motor vehicle emission inspection institutions and meet the requirements of the smart inspection and supervision plan of the State Administration for Market Regulation, this research developed a device-edge-cloud collaborative intelligent supervision system for black smoke detection. A customized black smoke dataset for inspection institutions was built, a detection model was trained and optimized based on YOLOv8 and deployed on an industrial edge computing box, and a visual supervision system was developed to connect with Suqian's “Tianyi Cloud Eye” cloud supervision platform. Field tests show the system's recognition rate meets the expected target. It enables full-chain traceability of detection and intelligent early warning of anomalies, effectively improves supervision accuracy, and provides technical references for smart inspection and supervision.

To improve the accuracy of dynamic pressure measurement in gas turbine combustors, this study investigates the influence of structural parameters of pressure tubing on its dynamic response characteristics, with emphasis on nonlinear behaviors under large-amplitude excitation. Based on the theory of acoustic wave propagation in pipelines, experiments were conducted using a modulated dynamic pressure generator to test pressure tubes with various lengths (20-200 mm) and diameters (2-6 mm). Results show that tube length dominates the phase lag, with phase difference proportional to the product of length and frequency. Reflection from the mounting seat is identified as the key factor causing resonance peaks in amplitude-frequency characteristics. The effect of diameter is governed by impedance matching: when the main tube diameter matches the fixed upstream and downstream sections, the system behaves as a transmission line with continuous impedance; when mismatched, the system becomes a resonator—small diameter (high impedance) excites high-frequency resonance, while large diameter (low impedance) excites low-frequency resonance. Under large-amplitude excitation, nonlinear effects further amplify the resonance peak of the small-diameter tube, resulting in gain exceeding unity—an abnormal amplification that deviates from classical linear acoustic theory. This study reveals the frequency-domain competition between linear dissipation and nonlinear resonance in the dynamic response of pressure tubes under large-amplitude conditions, providing guidance for the design and signal correction of high-precision dynamic pressure measurement systems.

Metrology, as the science of precise measurement, serves as a crucial foundation for technological development and social production. The evolution of metrology in Russia has traversed three distinct stages: the formation of the traditional system of weights and measures in Ancient Rus, the establishment of modern scientific metrology, and the development of a comprehensive modern standardized metrological system. This trajectory reflects a developmental path characterized by both unique national features and robust scientific connotations. By systematically examining the unit systems and application characteristics of ancient Russian weights and measures, analyzing Mendeleev's foundational contributions to modern Russian metrology, and elucidating the institutional framework and current development status of contemporary Russian metrology, this paper explores the historical patterns and core features of Russia's metrological development. This study aims to provide a reference for the advancement of China's metrological endeavors and international metrological exchange.

On-site calibration of water intake flowmeters is a core means to ensure the accuracy of water intake metering data, continuity of monitoring, and effectiveness of supervision. It is also a key technical support for implementing rigid constraints on water resources and improving the refined level of water intake supervision. Based on practical work experience, this paper analyzes and summarizes the problems identified in the on-site calibration of water intake metering facilities in the karst mountainous areas of Guizhou, specifically regarding the standardization of flowmeter installation, on-site comparative calibration, operation and maintenance management system, as well as on-site calibration service institutions.Guided by the problems, targeted countermeasures and suggestions are proposed from the aspects of standardizing flowmeter installation, strengthening the standardization of comparison and calibration operations, optimizing the operation and maintenance management mechanism, enhancing the effectiveness of industry supervision, and developing flowmeters with stronger adaptability to karst mountainous areas, aiming to provide strong support for the refined management of regional water resources.

To address the traceability challenges in medical mammography X-ray machines, this study designed and developed a low-energy mammography X-ray radiation device. The system features a dual-source configuration (molybdenum target and tungsten target) for generating RQR-M and RQA reference radiation qualities, and employs a top-down vertical irradiation geometry to accurately simulate the operational conditions of clinical mammography systems. This design enhances the efficiency of value transmission and minimizes the impact of scattered radiation on the surroundings. This paper elaborates on the core components, operational principles, and two measurement methodologies (coaxiality and uniformity) for characterizing the radiation field. Experimental focus was placed on the field uniformity at a distance of 0.6 m from the X-ray focal spot. Results demonstrate that the radiation field area with uniformity exceeding 95% is approximately 95 mm (horizontal) × 90 mm (vertical), which meets the calibration requirements for ionization chambers of commercial mammography dose meters. Repeated performance tests and long-term field application have confirmed the stability and reliability of the device, providing crucial technical support for the traceability of mammography equipment, radiation hazard control, and public health protection.

With the rapid advancement of new-generation information technologies such as the Internet of Things, big data, cloud computing, and artificial intelligence, the field of metrology is undergoing a profound transformation characterized by digitalization, networking, and intellectualization. As a core direction in the modernization of metrology, smart metrology offers novel solutions to persistent challenges in grassroots metrological work, including insufficient staffing amidst heavy workloads, difficulties in achieving comprehensive regulatory coverage, and the shallow utilization of measurement data. Grounded in the practical realities of grassroots metrology, this paper first elaborates on the connotation and characteristics of smart metrology, followed by a systematic analysis of the primary challenges currently facing grassroots metrology. On this basis, it focuses on exploring specific application scenarios and practical pathways for smart metrology in areas such as compulsory verification at the grassroots level, the construction of a credit system for metrology, the supervision of metrology related to people's livelihoods, and support for industrial services. Finally, the paper provides an in-depth analysis of potential obstacles—technical, financial, personnel-related, and institutional—that may hinder the implementation of smart metrology at the grassroots level, and proposes corresponding countermeasures and future prospects, aiming to provide theoretical references and practical guidance for enhancing the modernization of grassroots metrological governance capabilities.

In response to challenges within the energy data monitoring domain—including metering device parameter manipulation, insufficient bandwidth for traditional real-time monitoring, and constrained cloud computing resources—this study proposes an energy metering management and monitoring system centered on edge computing. The system utilizes an Internet of Things (IoT) sensor network to achieve comprehensive perception and real-time acquisition of energy data. By deeply integrating edge computing into its architecture, localized processing modules are deployed at edge nodes to swiftly execute critical tasks such as anomaly detection and fraud prevention. Through data filtering and analysis at the edge, the system significantly alleviates cloud data transmission burdens and enhances the efficiency of energy metering supervision.

Dental equipment is an essential device for clinical dental disease diagnosis, and medical dental performance testing model is the key to the quality control of dental equipment. At present, there is no relevant procedure standard in China.Through the introduction of the main components and working principles of the medical dental performance test model, the paper identifies three key test items of the medical dental performance test model according to the relevant literature, combined with the needs of actual detection and the characteristics of metrological detection. The results meet the requirements through multiple testing experiments, which proves that the testing method is feasible and can evaluate the performance of a medical dental performance testing model scientifically and reasonably, and improve the reliability of the dental performance testing model, which can protect the clinical diagnosis.

To address the pain points of traditional energy efficiency testing for storage water heaters—such as reliance on manual operation, complex procedures, poor equipment compatibility, long testing cycles, and the inability to perform synchronous multi-unit tests—a high-efficiency, accurate, and intelligent testing device was designed and developed. The device automatically measures the 24-hour standing loss coefficient and hot water output rate. Verification results indicate that the repeatability of five consecutive hot water output rate measurements is no more than 2.0%. The device supports parallel testing across multiple stations, utilizes intelligent weighing to replace manual handling, and employs programmed control for precise data acquisition and result determination, thus achieving an integrated solution for intelligent testing.

To address the inefficiency and poor consistency caused by the separate measurement of compression depth and frequency using different equipment as stipulated in the current “JJF 1748—2019 Calibration Specification for Cardiopulmonary Resuscitation Machines”, this paper innovatively designs a pneumatic depth test bench. This bench utilizes the compressibility of confined gas to simulate the mechanical response of the human thoracic cavity and incorporates a guide shaft mechanism to significantly reduce the lateral swing error inherent in traditional spring-based structures. Centered around this test bench, this paper further develops an on-site calibration tester capable of simultaneous and high-precision measurement of compression depth and frequency by integrating a high-precision laser displacement sensor, a pressure control system, and an ARM processor. Experimental verification demonstrates that the technical indicators of the tester surpass the requirements of the specification, exhibiting excellent safety, universality, and reliability, thereby providing an effective technical solution for the rapid and accurate calibration of CPR machines.

To address the limitations of current quality control for syringe pumps, which relies heavily on periodic verification and post-event assessment and lacks a prospective prediction mechanism for performance degradation trends, this study explores a machine learning-based method for metrological characteristic mining and performance prediction. Taking 284 single-channel syringe pumps from a tertiary-grade A hospital in Guangxi as research samples, the study collected key data on indicated error and repeatability under three typical flow rates, and constructed an analytical framework using K-Means clustering and Random Forest algorithms. The results indicate that indicated error displays significant differences between the two clustered groups, whereas repeatability shows no significant inter-group differences. Addressing the issue of high missed detection rates for abnormal samples caused by data imbalance, the Random Forest model was optimized using a cost-sensitive learning mechanism. This optimization significantly improved the recall rate for the performance-fluctuation group from 0.07 to 0.43, thereby enhancing the identification capability for potential high-risk devices. Although the overall prediction accuracy was adjusted to 62.8% due to increased safety redundancy, the model effectively reduces clinical missed detection risks. Future research should expand the sample size and enrich feature dimensions.

In water environment monitoring, ammonia nitrogen (NH₃—N) automatic analyzers are widely used for online determination of NH₃—N concentrations in surface water. However, in practical verification and routine operation, limited repeated measurements due to time and efficiency constraints often result in insufficient sample sizes, posing challenges to uncertainty evaluation. This study applies an improved extremely small-sample grey uncertainty evaluation method to analyze the measurement uncertainty of indication errors of an ammonia nitrogen automatic analyzer, and compares the results with those obtained using the traditional Bessel formula. The proposed method significantly enhances the stability and reliability of uncertainty evaluation under small-sample conditions, providing important support for improving data quality and optimizing verification efficiency in ammonia nitrogen automatic monitoring.

To solve the problems of low efficiency and high cost in detecting the vertical deviation of the phase center of GNSS receiver antennas, a measurement method utilizing a two-dimensional turntable is proposed. By analyzing the baseline repeatability under different observation durations, the optimal observation period is determined and statistically validated using an F-test. The two-dimensional turntable is automatically controlled to position the GNSS receiver and antenna for static observations at various azimuth and elevation angles. The vertical phase center offset of the GNSS antenna is derived through baseline processing, coordinate fitting, and geometric analysis. The repeatability of the vertical offset measurements is 0.6 mm, and the deviation from the NGS reference value is less than 1 mm, demonstrating high measurement accuracy and improved detection efficiency of the proposed method.

The actual gum analyzer is a key instrument for determining the content of nonvolatile residue (gum) in light fuels such as gasoline and aviation fuel. By simulating the heating and evaporation conditions of the engine intake system, it accurately measures the colloid mass (unit: mg/100 mL) formed by fuel evaporation at a specific temperature and air flow rate. This index directly reflects the stability of fuel and the tendency to produce deposits. It is the core basis for evaluating the storage stability of fuel and judging whether it will lead to coking and blockage of engine intake system. It is widely used in quality control in the fields of oil refining, quality inspection, aviation and scientific research. The accuracy of the instrument depends on strict temperature, flow control and high-precision balance weighing, and it needs to be calibrated and verified by using standard materials regularly.

针对当前加气站库存储气（液）量手工计算麻烦，计算机应用软件又未开发这一现状，该文提出了何时采用近似方法、何时采用标准方法计算加气站库存储气（液）量。并先用理论公式阐述，然后通过实例解答加气站库存储气（液）量计算全过程，对加气站具有很好的帮助作用。

为了实现对测量设备的自动核查，设计并实现一套能对测量设备进行自动核查的系统。采用LabVIEW图形化编程语言为开发平台，使用LabSQL数据库操纵模块和调用Microsoft Excel程序来实现数据存储和证书报表生成的功能。通过试用表明：该系统可以避免手动核查中的粗大误差，提高工作效率，能够很好的满足测量设备自动核查的需要。

回路电阻测试仪是用于测量开关、断路器、变压器等设备的接触电阻。直流电阻测试仪是用于测量变压器、互感器、机电绕组等感性被测对象的直流电阻的专用测试设备，也被称为“直流电阻快速测量仪”。文章介绍了直流电阻测试仪测量不确定度评估，为直流电阻测试仪测量不确定度的评估起到模板作用。

本文从四个方面分析了依据JJG205-2005规程检定干湿球温度计，可能产生检定误差的原因，并结合工作实际，提出相应的解决方法及注意事项，能有效提高对干湿球温度计检定的准确度。

摘要：Excel具有强大的计算、函数及数据分析等功能，它可以进行各种数据的处理、统计分析和辅助决策操作。利用EXCEL函数功能实现量块数据自动化处理、分析、判断，对于提高量块检测工作质量和效率，减少检测输入差错率十分有帮助。

文章从5个方面出发分析了热量表生产与应用过程中产业计量研究的必要性，同时从热量表的工作原理出发，以产业计量的思维，从流量测量、温度测量、耐久性与寿命评价、电磁兼容与环境几个方面，系统分析热量表产业的计量测试技术需求。

计量是国家质量技术基础中的重要组成部分。建立计量管理信息系统（简称“TJMMIS”）是为了更好服务于计量行政管理部门、法定计量检定机构、使用计量器具的企事业单位以及社会公众，规范计量行政管理、执法检查、检定校准等行为，切实落实企业主体责任和维护公众知情权，提高量传溯源覆盖度和有效性，促进计量技术创新和成果转化，整体推进法制计量、科学计量、诚信计量、民生计量、工业（产业）计量，在大数据时代下采用、政府、企业、公众三位一体的计量信息管理系统,实现向监管部门提供决策支持和风险预警数据、向企事业单位推送计量器具管理和服务、向公众提供计量器具检测、查询服务。系统涵盖计量信息管理子系统、计量检定业务子系统、计量政府监管子系统、计量企业服务子系统。

文章介绍了实验室仪器维护和保养得一些方法和注意事项。

数字式双钳相位表广泛地应用于电力系统，是重要的现场试验用仪器，关系到企业的安全生产，为了确保其数值的准确可靠，因此对该表的校准显得尤为重要，目前国家没有制定数字式双钳相位伏安表的检定规程或校准规范。通过对多种型号的数字双钳相位伏安表的工作原理进行研究，针对数字式双钳相位伏安表的特点和应用范围、确定了数字式双钳相位伏安表计量特性，文章主要介绍了数字式双钳相位伏安表的校准方法，内容包括环境条件、测量标准择、校准项目、校准方法。