To solve the problem of remote transmission of legal time measurements and fill the gap of traceable time standards and time-measuring instruments, the remote time traceability method was studied, and the remote time traceability device NIMDO was developed by disciplining rubidium, cesium, and hydrogen atomic clocks with reference to the atomic time national primary standard (UTC(NIM)) and using the GNSS time and frequency transfer method, and a remote time traceability system was preliminarily constructed based on the device. Through various experimental verifications, the device achieves a high-performance time scale at the remote end and synchronizes with UTC(NIM) in real-time, which is equivalent to reproducing UTC(NIM) at the remote end with a certain time and frequency deviations, and the time deviation of NIMDO from UTC(NIM) is better than ±10 ns and frequency deviation is better than ±1×10−13 in over 90% of the time, and the time deviation stays within ±5 ns in more than 87% of the cases.
Abstract: The time and frequency standards used by many power system organizations need to obtain a higher precision time standard source for time and frequency comparison to maintain the accurate operation of atomic clocks, thus putting forward requirements for their remote calibration, synchronization of time and frequency magnitude traceability, and effectiveness. Given the above problems, the GNSS time and frequency transfer method based on the common view of navigation satellites is proposed to solve the problem of remote calibration of clocks by analyzing the demand for time and frequency measurements in power systems and the current status of research technology; a remote time and frequency traceability system for power systems that can be timely traced to the national time and frequency reference is designed, and the specific implementation plan and data processing process based on the time and frequency transfer method are clarified. Through the analysis of the time and frequency standard device and the national benchmark UTC (NIM) co-view data, the research results show that the absolute value of the deviation (1-day) is no more than 10 ns, which solves the problem of synchronization and timeliness of traceability.
Abstract: By analyzing the high-precision time-frequency synchronization demand of communication system and the characteristics and applicability of existing testing methods, satellite common-view equipment is selected as the testing reference, and the actual testing of frequency and time performance of communication network equipment is carried out to realize the application of satellite common-viewi technology in the testing of communication synchronization equipment. The test results show that the satellite common-view technology can better meet the testing requirements of the current communication synchronous network. Satellite common-viewing technology is studied and its application in the test of communication synchronous equipment is realised in this paper. Firstly, the high precision time-frequency synchronization requirements of the communication system and the characteristics and applicability of the existing test methods are analyzed. Secondly, equipment based satellite co-viewing technology is selected as the time-frequency reference to test the time-frequency performance of the actual communication network equipment. The test results show that satellite co-viewing technology can meet the test requirements of communication synchronous network well.
Abstract: To meet the needs of manufacturers in the design and development of time service products, product finalization, factory inspection, and other processes on high-precision key indicators test inspection, a high-precision time server product performance verification test method is designed based on synchronization to UTC (NIM) time-frequency source, that is, the remote real-time traceability of NIMDO. By testing the time server using the crystal discipline algorithm with stepwise modulo operation compensation, when using different performance GNSS receiver modules A and B as external reference time sources, the average time deviation of the time server from NIMDO is 8.6 ns and 2.8 ns respectively using the designed test method, which meets the requirements of the key indicators of the product seriation in both standard type and high-end type.
Abstract: Time interval counters are widely used in time and frequency calibration. Aiming at the measurement of metrological characteristics of rubidium frequency standard and cesium frequency standard, a time offset measurement system based on SR620 was designed to measure the relative frequency offset, frequency stability and daily frequency drift rate, and draw the frequency stability curve and frequency drift rate curve. The experimental results show that the measurement results of the system are expected and can be used for time and frequency traceability and calibration.
Abstract: This paper introduces a simple oven-controlled crystal oscillator (OCXO) disciplined module developed by using high precision time measurement technology, Kalman filtering algorithm, and PID feedback control principle. This module can discipline OCXO of frequency accuracy 10−7 to 10−10 without using FPGA and complex algorithms and is suitable for device development and achievement transformation of researchers who are new to the field of time and frequency measurement. The research group has applied this module in the calibration of the vehicle timing system at the airport drop-off station. Given its small size, it can also be used in the time calibrator, time synthesizer, and other standard instruments that allow the input of external frequency standard, to further improve the time and frequency parameter of the equipment.
Abstract: In this paper, through the establishment of a satellite common-view atomic clock discipline device, the local atomic time is compared with the national time and frequency reference station. Results show that the standard deviation of the rubidium clock is 2.19 ns, the stability of time deviation (1 day) is less than 1×10−9, the relative frequency deviation is −8.42×10−17, the frequency stability (1 day) is less than 2×10−14, and the discipline standard deviation of cesium clock is 1.5 ns. The stability of time deviation (1 day) is less than 1×10−9, the relative frequency deviation is 7.03×10−17, and the frequency stability (1 day) is less than 1×10−14. The local atomic time is effectively traced and provides technical validation to improve the verification system table of the time standard.
Abstract: In this paper, reference materials for transmission electron microscope (TEM) magnification calibration and their traceability were studied, and the TEM magnification and contamination/drift rate calibration methods and uncertainty evaluation of calibration results were carried out. This study can provide an accurate and reliable calibration method for measuring the results of TEM in scientific research and industrial applications.
Abstract: In this paper, an experimental water tank and a tank crane are used to design a calibration test method. By carrying out multiple sets of ocean current measurement experiments, the measurement performance of the electromagnetic ocean current meter is technically analyzed. The results show that the absolute value of the maximum indication error of the flow velocity is 1 cm/s, and the absolute value of the maximum indication error of the flow direction is 2°. The tank flow field calibration technology provides a new and effective way for the ocean current parameter value transfer of electromagnetic current meters.
Abstract: Given the problems faced by the indentation depth testing device in the calibration process, through a large number of experiments and data research, we propose to use the grade 2 gauge block combined with mechanical comparator and bench to calibrate the indicated value error, and evaluate the measurement uncertainty of the indicated value error, and the method fully meets the calibration requirements.
Abstract: By comparing the three known torque multiplier calibration methods in China, the differences in their calibration methods and calculation results are analyzed, and the problems of inconsistent calibration methods, inconsistent calibration data processing, and incomplete evaluation and analysis of results are pointed out. By analyzing the uncertainty evaluation process of the existing torque multipliers, it is pointed out that there are problems of imperfect measurement models and incomplete analysis of uncertainty sources, and the measurement uncertainty evaluation method and process are given with the actual use parameter (magnification) of the multipliers as the evaluation object. The analysis of the evaluation results shows that the measurement uncertainty of the torque multiplier can be reduced when the torque tester measuring the input torque and the output torque is traced by the same superior standard.
Abstract: Starting from RFID、RFI technology and timing principle of IC card timing device, this paper introduces the application of radio frequency interference technology in the verification of IC card timing device, and the uncertainty analysis is given. This method solves the problem of timing synchronization in the verification process well.
Abstract: Nylon 66 salt is a monomer of Nylon 66 resin. In order to ensure that adipic acid and hexamethylene diamine react in an equimolar ratio in the industry, adipic acid and hexamethylene diamine are generally made into Nylon 66 salt before the polycondensation reaction to produce nylon 66 resin. The article describes the technical application of the critical angle refractometer for sugar particle size measurement in the production of Nylon 66 brine solution and the operation and maintenance of the instrument.
Abstract: Crude oil measurement includes flow meter measurement, rail tank measurement, vertical metal tank measurement, and digital indicator scale measurement. In order to avoid large measurement errors, another supervision measurement method is usually adopted based on the handover measurement method to ensure accurate operation. Combined with the actual measurement work, this paper mainly discusses the comparison between digital indicating scale and vertical metal tank.
Abstract: This paper introduces the measurement verification technology of the gas ultrasonic measurement system. Through a comprehensive analysis of the performance evaluation of multiple measurement stations of a natural gas pipeline company, the problems in the field measurement verification are analyzed, the measurement verification method is optimized, and the effects of sound velocity verification result overruns, temperature verification result overruns and gas quality components on sound velocity verification are investigated combined with some typical experiments. Experiments have proved that the measurement verification technology is an effective measure to ensure the accuracy and reliability of the measurement system.
Abstract: This paper introduces the intelligent logistics system developed by using computer software development technology, mobile phone app software development technology, network communication technology and face recognition technology, and other Internet of Things technology to realize the functions of appointment pick-up, intelligent weighing, electronic security inspection, and quantitative loading of dangerous chemical transport vehicles. Through this system, it can effectively reduce the safety hazards brought by the gathering of hazardous chemical vehicles, improve the efficiency of oil capacity measurement and transfer in large ports, effectively control the safety of admission vehicles and improve the automation level of enterprises.