Abstract: Traditional time and frequency measurement standards are mostly provided by rubidium atomic frequency standards or high stability crystal oscillators, and rubidium atomic frequency standards need to be periodically traced to higher-level measurement standards, which has a long calibration period, and the instruments are easily damaged during the process of sending them for inspection. The proposed remote time and frequency traceability system with the time and frequency standard device (NIMDO) as the core realizes real-time time and frequency traceability to the atomic time scale national primary standard UTC (NIM) and uses NIMDO as the reference frequency source to build many measurement standards in the time and frequency field, forming a three-level traceability system from the national primary standard to the measuring instruments.
Abstract: With the development of intelligent transportation, the demand for high accuracy time and frequency is gradually increasing. At present, high-performance atomic frequency standard is widely used in the measurement industry, and the demand for remote calibration of atomic frequency standard is also increasing. Taking NIMDO as the reference time and frequency source, the NTP and rubidium atomic frequency standards are calibrated by remote calibration, which solves the problem of time traceability in the traffic field, provides a legal basis for measurement results and greatly improves the calibration efficiency.
Abstract: Using GNSS technology, the establishment of a demonstration station for remote time and frequency transmission and traceability application in Henan is introduced. By adopting GNSS co-viewing method, building a satellite navigation time and frequency application platform which can be traced to national atomic time-scale primary standard in real-time, establishing Henan provincial time standard, realizing remote transmission and traceability of time and frequency, the absolute value of the deviation of the moment (1-day average) is not more than 10 ns, and the standard uncertainty of traceability (deviation) is not more than 10 ns, providing high precision time and frequency standard service for the society.
Abstract: This paper introduces the significance of time and frequency remote transmission standard establishment of Xinjiang Institute of Measurement and Testing and analyzes the current situation of time and frequency remote transmission in the Xinjiang region. Through the analysis of the accuracy and stability of this set of standards, it is proved that the device meets the specification requirements and can establish the highest time and frequency standard in Xinjiang region, and realize the use of time and frequency remote transmission, traceability, and calibration technology in Xinjiang the region.
Abstract: The high-accuracy time and frequency transfer system is an important component of time and frequency service and a bridge linking China's time and frequency reference to standards and time and frequency users at all levels, which plays a pivotal role in the national economy and national defense construction. Using the remote time traceability device - NIMDO developed by the National Institute of Metrology, and based on the quasi-real-time verifiable traceability or timing technology of GNSS time and frequency transfer, a precise time and requency traceability system is established to realize the comparison between the remote time and frequency source and UTC (NIM), the national measurement reference of atomic time scale. Through system verification and analysis, 78.17% of the time deviation between NIMDO and UTC (NIM) is within ±5 ns, and 88.49% of the relative frequency deviation (day average) is within ±1×10−13. The results showed that the system solved the problem of precise time-frequency traceability and synchronization.
Abstract: Nowadays, more and more new energy vehicle charging pile testers provide the function of time calibration, but this function has not yet achieved traceability, and the accuracy of the downward transmission time cannot be guaranteed. This paper uses the remote time and frequency traceability system that can be traced to UTC (NIM) in real-time to achieve accurate time traceability of the new energy vehicle charging pile tester. At the same time, according to different time differences and time accuracy requirements, different methods are used to achieve traceability up to the millisecond level with an expanded uncertainty of 0.18 ms.
Abstract: The reference material of caffeine in methanol-water for LC-MS calibration was developed, and uncertainty was evaluated. Using pure caffeine, chromatographic grade methanol, and laboratory first-grade water as raw materials, the purity of the pure caffeine product was verified by the mass balance method, and the standard method weight-volume method was used to prepare the reference material of the caffeine solution in methanol with a concentration of 9.94 mg/L. Liquid chromatography was used to compare the value of the 9.94 mg/L standard solutions of caffeine in methanol with the national certified reference material GBW(E)130453, and the uniformity, short-term stability, and long-term stability of the solution were studied. The results show that the developed 9.94 mg/L reference material of caffeine in methanol-water has good uniformity and stability, with a relative extended uncertainty of 2% (k=2) and a validity period of 12 months.
Abstract: In the process of verification/calibration of the absorption type wavelength standard filter of JJG1034-2008 "Reference Filter for Calibration Spectrophotometer", there are a large amount of data to be processed, and the process is tedious. According to the extreme value theory and based on MATLAB and EXCEL hybrid programming, the identification, calculation, and rating of the characteristic peaks are realized, and the calculation results are given in the form of EXCEL tables.
Abstract: High-precision leveling is an essential method in seismic deformation monitoring and other fields. The leveling rod and leveling instrument are important instruments for leveling, and measurement verification should be carried out on schedule. To improve the credibility of the verification results of the leveling rod measurement, it is of great significance to develop a reliable measurement system to analyze and control the errors during the verification experiment. According to the national metrological verification regulations of JJG 8-1991 "Level Rod", this paper introduces a laser ruler interferometric measuring system that meets Abbe's measuring conditions, which is used to verify the true length of the meter interval and the division error of the leveling rod. Analyze and prevent errors one by one during the verification process of the leveling rod. The analysis results show that the laser interferometry system can meet the requirements of the national metrological verification regulations for the accuracy of other verification devices not less than 6 μm.
Abstract: According to the thermal efficiency measurement method in the new national standard GB 12021.6-2017 “Minimum allowable values of energy efficiency and energy efficiency grades”, the thermal efficiency of the electric rice cookers is measured, and the uncertainty of the thermal efficiency measurement results is evaluated to more accurately determine the energy efficiency grade of electric rice cookers on the market.
Abstract: The bell prover is a measurement standard that uses air as the medium to transfer the gas flow quantity value. The national metrological verification regulation JJG 165-2005 "Verification Regulation of Standard Bell Provers of Gas Flow" stipulates that bell prover can be performed by the volume method and geometric method. China has not conducted any systematic experimental research on the verification method and its process of the bell provers and needs to solve the problem of transferring the measurement value of gas flow measurement. There is no direct correlation (transfer) between the values of bell prover gas flow from the national metrology institute to each provincial metrology institute. The individual components are traceable to length, mass, and time references, respectively. This paper discusses the research of the method of transferring the values of the gas flow standard device to establish the physical quantity transfer relationship of the national primary standards and the local standard gas flow standards. The test proves that the standard table value transfer relationship can be used to regulate the value transferred by the bell prover gas flow device, so that the national flow primary standard, the provincial flow standard, the local prover standard value can be linked to achieving the traceability.
Abstract: Aiming at the problem that the traditional inner coating detector is limited to the detection of unwelded pipe sections and large-diameter pipes, a detection system for damaged points of inner coating based on pulsed electric spark was developed. To meet the requirements of the detection distance on-site, a pneumatic pump is used as the power source, and a power valve structure is designed to ensure that the detection distance can reach more than ten kilometers. For the actual situation that the pipe diameter is only 8 cm, the detection system is designed into four sections. Each section is installed with a miniature pulse transformer, miniature pulse high voltage drive circuit, miniature main control circuit, and high capacity lithium battery. The results of the joint debugging of software and hardware show that the detection system is reliable and stable, and can automatically detect weak pulse currents and identify damaged points of the inner coating, and has the characteristics of long detection distance and compact structure.
Abstract: This paper introduces the working principle of hemodialysis equipment tester, discusses the calibration method of the flow parameters in the hemodialysis equipment tester, studies and designs a small flow calibration device for the flow parameters calibration of the hemodialysis equipment tester, which is based on the liquid flow device of the static mass method, combined with the standard flowmeter as the measurement standard, and realizes the calibration of hemodialysis equipment tester calibration of flow parameters, the results show that calibration of standard flowmeter and analysis of the uncertainty of the device can meet the calibration requirements of flow parameters.
Abstract: For dust online monitoring system, the indexes such as indicated value error can no longer fully reflect the performance difference of different types of light scattering dust sensors, and the tolerance and long-term stability of high concentration dust become important indexes that need to be included in the assessment, and the high concentration flooding experiment can be used as the assessment method for these two indexes. Practice shows that the dust meter with the function of air warping protection can still maintain good metering performance after the high concentration dust flooding test, and can be used for online monitoring of dust in the outdoor environment.
Abstract: According to GB/T 13609-2017 "Natural Gas Sampling Guidelines", the classification of natural gas sampling methods, their respective technical characteristics, and industry applications are introduced in detail, especially the use of indirect sampling methods in natural gas analysis and testing is comprehensively analyzed and studied. The influences of different sampling methods on the analysis results were explored by using three sampling methods: aeration method, controlled flow method, and prefilled helium gas method. The results show that the aeration method is simple to operate and has little influence on the analysis results, which can be applied to the indirect sampling of natural gas.
Abstract: By analyzing the structure and function of the energy management system, and consulting a large number of standards and specifications, the measurement methods of the energy management system are summarized. The measurement requirements and methods of the energy management system are introduced, and the methods are verified to be reliable and feasible.
Abstract: There is no unified verification regulation or calibration specification for inclinometers. To better ensure the accuracy and reliability of measurement traceability, this paper gives clear technical indicators for different types of inclinometers, and gives the technical indicators of corresponding verification devices, discusses the verification methods in detail, and analyzes the measurement traceability and uncertainty of the measurement performance of inclinometers.