2021 Vol. 65, No. 8

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2021, 65(8): 3-6, 28. doi: 10.12338/j.issn.2096-9015.2020.9038
Abstract(201) HTML (49) PDF(20)
Abstract:
At present, there are many kinds of multi-parameter measuring instruments with the function of half-value layer(HVL) measurement in the market, which can be used to measure the HVL value of diagnostic X-ray equipment. Based on three types of multi-parameter measuring instrument, we analyze many factors that may affect the measurement of HVL, such as X-ray tube voltage, tube current, exposure time, and the placement of the HVL instrument, and then design several groups of control tests. The test results show that the deviation of the tube voltage leads to changes of the HVL and that more stable measurement results can be obtained with appropriate exposure time.
2021, 65(8): 7-10. doi: 10.12338/j.issn.2096-9015.2020.9056
Abstract(186) HTML (40) PDF(33)
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This paper mainly introduces the development, application and main technologies of medical wearable physiological parameter monitoring equipment. At present, there is no specific metrology technical specification for this kind of equipment. Based on the standards and metrology methods of the relevant traditional medical equipment, this paper explores and analyzes the main metrology parameters and technologies of medical wearable physiological parameter monitoring equipment.
2021, 65(8): 11-14. doi: 10.12338/j.issn.2096-9015.2020.0218
Abstract(151) HTML (50) PDF(9)
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This paper proposes a teaching design for comparing and analyzing the same and different verification items of mercury sphygmomanometers and electronic sphygmomanometers. The design is based on analyzing the similarities and differences between the metrological verification regulations of mercury sphygmomanometers and electronic sphygmomanometers and teaching purposes of sphygmomanometer metrological verification courses are taken into account. The aim of the design is to enable students to better master the metrological verification techniques of the two kinds of sphygmomanometers. After four years of teaching practice, the expected teaching effect has been achieved.
2021, 65(8): 15-18, 54. doi: 10.12338/j.issn.2096-9015.2020.9059
Abstract(47) HTML (79) PDF(8)
Abstract:
The calibration repeatability of CO2 laser and the power range that can be calibrated are reduced by the laser's poor power stability and adjustability. The repeatability can be improved by monitoring the CO2 laser power in real time with a beam splitting system. But for 10.6 μm laser, the reflectance of ZnSe beam splitters is very unstable, which leads to fluctuation of the monitor ratio. Based on the principle of chopper, a chopper sampling and attenuation system was developed. The attenuation range is 0.2%~50%. Through an optimization design of the control unit, the interference between two sets of choppers in the same beam was avoided. The monitor ratio of the calibration setup was tested, and the monitor ratio instability was less than 1.1%, which is significantly better than that of ZnSe beam splitters (8.6%). The repeatability (k = 1) of the correction factor of the measured laser power meter improved from 1.09% (without a monitor) to 0.62%. The chopper sampling and attenuation system proposed in this paper improves the repeatability of calibration results and increases the power adjustment capability in CO2 laser power calibrations.
2021, 65(8): 19-23, 41. doi: 10.12338/j.issn.2096-9015.2020.0414
Abstract(52) HTML (16) PDF(16)
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An automatic calibration system for cylindrical measuring pins based on LabVIEW was developed. A laser micrometer was used to measure the three pins in a non-contact way. A footswitch was used to control the measurement process of the laser micrometer. The measurement data from one group of three pins was packed up in a "cluster", which was convenient for subsequent automatic sorting according to the specifications of the pins. The electronic original record was automatically generated based on the ActiveX technique and the report was generated after just one click by a LIMS system. The actual operation showed that the system can improve detection efficiency, avoid human errors, and reduce workloads. The system can be widely used in various calibration and testing laboratories.
2021, 65(8): 24-28. doi: 10.12338/j.issn.2096-9015.2020.9009
Abstract(47) HTML (46) PDF(9)
Abstract:
An angular velocity measurement system for rotary table using ring laser gyroscope and self-calibration angle encoder is designed, which enables the measurement and data acquisition of the angular position and angular velocity of rotary table in a single circumference range. A test platform is built using a self-calibrating angular encoder and a ring laser gyroscope to monitor the motion state of the rotary table, and the collected data are analyzed to obtain the angular position and angular velocity information. Through experiments at different speeds, a series of angular positions and angular velocity deviation curves and their Fourier transform analysis results in the single circumference range of the rotary table are obtained.
2021, 65(8): 29-32. doi: 10.12338/j.issn.2096-9015.2020.0427
Abstract(163) HTML (61) PDF(4)
Abstract:
The measurement of flow velocity is usually made by counting pulses occruing in a flow meter in a time interval. However, this method cannot meet the need for real-time monitoring of flow velocity. This paper proposes a design of a flow meter module, which realizes instantaneous flow-velocity detection. The module includes circuits for signal processing, instantaneous velocity detection, and flow detection and a 485 interface. A test platform was built to verify the design. The relationship between the rotational speed of the flow sensor and the original output signal and the relationship between the pulse width and the signal frequency of the flow sensor were investigated. An MCU was used to upload the pulse width to a server to monitor the flow velocity in real time. Experiments showed that the module can detect flow signals with frequencies below 510 Hz in real time, with an error rate of pulse detection less than10−6.
2021, 65(8): 33-35. doi: 10.12338/j.issn.2096-9015.2020.0205
Abstract(69) HTML (15) PDF(19)
Abstract:
With the development of biotechnology, the demand for PCR calibration has risen sharply. This paper decribes the PCR process and proposes a PCR calibration device, which can realize the temperature calibration for PCR devices.
2021, 65(8): 36-41. doi: 10.12338/j.issn.2096-9015.2020.9035
Abstract(131) HTML (43) PDF(13)
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During the Antarctic summer from 2019 to 2020, the 36th Chinese scientific expedition to Antarctica made absolute gravimetric measurements at the Zhongshan Station using a domestic absolute gravimeter, NIM-3C, independently developed by the National Institute of Metrology, China. The measurements provide a calibration point for the polar ocean gravity. Besides, continuous observation and research were conducted for more than 30 days. The standard uncertainty of the calibrated value of the absolute gravity at the measurement point is better than $3\times {10}^{-7}\;\mathrm{m}\cdot {\mathrm{s}}^{-2}$. The measurements have made China's polar ocean gravity value traceable to the national measurement datum, which is traceable to the International System of Units.
2021, 65(8): 42-45. doi: 10.12338/j.issn.2096-9015.2020.9033
Abstract(103) HTML (20) PDF(16)
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Detection Systems for Vehicle Honking (DSVHs) based on a microphone array can provide evidence for regulating improper honking behavior. The traceability of DSVH monitoring moving vehicles is an important problem and still needs to be solved. There is a lack of consensus about the solution of this problem. Based on the principle and efficacy of DSVH, the influence of Acousto-Optic Image Time Consistency (AOITC) and the Accuracy of Sound Pressure Levels (ASPL) on the accuracy of DSVH was analyzed . The calibration method for AOITE and ASPL is provided in this paper. Two DSVHs from different manufacturers on the market were tested. The results showed that the AOITC was less than 50 ms and its impact on the accuracy of DSVH could be ignored, the ASPL was within 3 dB, and the result at 4.0 m was better than those at 3.5 m and 3.0 m.
2021, 65(8): 46-50, 45. doi: 10.12338/j.issn.2096-9015.2020.9005
Abstract(156) HTML (34) PDF(46)
Abstract:
Air sampler is an important measuring instrument for environmental monitoring. With the rapid development of environmental protection industry, the direct-reading air sampler has been widely used.The current verification regulation JJG 956 "Air sampler" is only applicable when the standard apparatus is soap film flowmeter, whereas it is not applicable to the air sampler whose meter is a rotameter or the flow direct-reading type air sampler. Meanwhile, the corresponding standard meters are also developing rapidly and more results showed that the laminar differential pressure mass flowmeter has more advantages than the soap film flowmeter in the regulation. It can not only improve calibration efficiency, but also realize automatic calibration or even remote calibration. In this paper, the laminar flow differential pressure mass flowmeter calibration method of flow direct-reading type of air sampler was studied. The mathematical model of flow rate and relative indication error used in the calibration condition was proposed, and the uncertainty of indication error was also analyzed in detail. In addition, the evaluation example was given to prove the feasibility of the method of calibration of direct-reading type of air sampler.
2021, 65(8): 51-54. doi: 10.12338/j.issn.2096-9015.2020.0370
Abstract(39) HTML (22) PDF(9)
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This paper proposes a method for calibrating the sensitivity of the current-sound pressure level system in an acoustic transducer. The uncertainty evaluation and a conformity nalysis of the conversion of permissible errors are also included. The desired calibration results were obtained, which can shed light on sensitivity calibration for acoustic transducers.
2021, 65(8): 55-58. doi: 10.12338/j.issn.2096-9015.2021.0504
Abstract(144) HTML (94) PDF(18)
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The average-speed control is a measure for measuring and controlling the spead of motor vehicles based on measurement of distance and time. Its key components consist of cameras triggered by monitoring terminals, recognition of vehicle information, and data processing. The shortest distance of road sections is obtained by a motor vehicle driving in fixed lanes in China at present. This method ignores lane changes of the vehicle and the distance obtained is not the shortest distance the motor vehicle can travel. This paper proposes a new method to calculate the shortest distance that a motor vehicle can travel with an interval-speed measurement system. The principles and key points of the method are provided.
2021, 65(8): 59-61. doi: 10.12338/j.issn.2096-9015.2020.0029
Abstract(35) HTML (15) PDF(5)
Abstract:
This paper proposes a verification method for electronic single-and-multi-point inclinometers, identifies technical indexes of well deviation angle, azimuth angle, and tool surface angle, and puts forward requirements for each performance index. The method was used to verify electronic single-and-multi-point inclinometers from different manufacturers. The results showed that the method can be used to evaluate the metrological performance of electronic single-and-multi-point inclinometers.
2021, 65(8): 62-65. doi: 10.12338/j.issn.2096-9015.2020.9015
Abstract(313) HTML (53) PDF(53)
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Soap film flowmeter is an important measuring instrument for environmental monitoring. In order to meet the effective traceability of micro gas flow in low-pressure test of flow meter for environmental monitoring, reduce the impact of gas humidity on the accurate measurement of soap film flowmeter, and improve the reliability of micro gas flow value transmission. In this paper, the operating characteristics of soap film flowmeter are analyzed, and the calculation method of humidity correction for micro gas flow is given. The results show that the humidity correction calculation method can effectively reduce the influence of humidity on the metering characteristics of soap film flowmeter.
2021, 65(8): 66-70. doi: 10.12338/j.issn.2096-9015.2019.9050
Abstract(127) HTML (38) PDF(15)
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The functional relationship between the non-equilibrium carrier lifetime and the injection level in single crystalline silicon, and the difference between the minority-carrier lifetime and the recombination lifetime of minority- and majority-carrier are elaborated. A set of measured lifetime and injection level data are obtained by the variable light intensity measurement. The function curves of the carrier lifetime and the injection level are obtained by the fitting method, which is consistent with the S-R-H model. According to the theory and experimental results, the scheme of improving the consistency of carrier lifetime measurement is proposed, and the foundation for the production of the minority-carrier lifetime reference material is laid.
2021, 65(8): 71-75. doi: 10.12338/j.issn.2096-9015.2020.0425
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When measuring electric energy under real-load conditions, the voltage applied to the current input of the standard meter introduces unwanted electric energy, especially at low currents. Experiment results showed that the voltage applied to the current input under real-load conditions produces capacitive leakage current through the distributed capacitance. The leakage current is added on the energy/power measuring circuit, which leads to errors in the measurement of the current amplitude and phase in low-current ranges.