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Abstract:
The acoustic laboratory of Zhijiang laboratory includes anechoic room, semi-anechoic room, reverberation room and listening room. Combined with the overall layout of the experimental building, the internal structural dimensions of the acoustic laboratory are determined, and the acoustic performance design requirements are put forward, which provides a reference for the design and planning of similar acoustic laboratories. After completion, the acoustic performance of anechoic chamber, semi-anechoic chamber, reverberation chamber and listening chamber is tested respectively according to national calibration specifications JJF 1147 and JJF 1143. The results show that the acoustic laboratory has achieved the expected design goal, can provide high-precision acoustic environment, and provides basic environmental conditions support for the corresponding acoustic research in Zhijiang laboratory.
Abstract:
Nucleic acid is the carrier of genetic information. With the rapid development of in vitro diagnostic technology based on nucleic acid amplification, nucleic acid detection is widely used in medical diagnosis, forensic identification, import and export inspection and quarantine, and species evolution research etc. Nucleic acid reference material is the gold standard to ensure the accuracy and traceability of nucleic acid test results. Both the WHO and Chinese Food and Drug Administration stipulate that in vitro diagnostic reagents need to use international and national standard materials or factory-level standards to trace their accuracy. The analysis of the carcinogenic mechanism of HER2, BRAF, EGFR and other gene mutations has prompted the listing of a series of targeted therapies such as trastuzumab, veilofenib, and rituximab, which has caused a large gap in Chinese nucleic acid reference materials. Due to the complex structure, easy degradation and large molecular weight of nucleic acid, it is difficult to meet the requirements of uniformity and stability. Therefore, the development of nucleic acid reference materials is slow. This article will briefly review the preparation methods of nucleic acid reference materials and domestic and abroad research progress, and provide references for the efficient development of nucleic acid reference materials for in vitro diagnostics.
Abstract:
This paper discussed the performance evaluation and the measurement technology of OCT the principles, technical classification, commercial development, measurement parameters and standard. It summarized of the domestic and foreign research progress in measurement methods of ophthalmic OCT system such as the calibration phantom, system resolution, signal-to-noise ratio/contrast, image quality, so laid a foundation for the further improvement of OCT standardization in ophthalmology.
Abstract:
Proton radiotherapy has become a precision radiotherapy technique owing to the superiority of Bragg Peak on the depth-dose distribution. This review provides the details of three detectors applying in reference dosimetry as well as the corresponding limitations in clinical proton modalities. Further discussions on the corrections and improvements when measuring proton beam dosimetry have been proposed combined with Monte Carlo techniques. Also the state-of-the-art determination on micro-dosimetry of proton beams has been summarized extensively.
Abstract:
The instrumental neutron activation analysis has the advantages of high sensitivity, no need for sample pretreatment, and a wide variety of measurable elements. It is one of the common methods for analyzing the element content of atmospheric particulate matter and can provide an important data basis for the analysis of pollution sources. This article summarizes the quality assurance process of each experimental process in the NAA laboratory using relative comparison method and single comparator k0 method to analyze atmospheric particulate matter samples, as well as internal and external quality control methods.
Abstract:
Aiming at the problem of balancing the calibration cost and calibration accuracy of industrial robots, a low-cost three-dimensional high-precision contact self-calibration system for industrial robots is researched. The three-dimensional calibrator is installed in the end position of the robot (TCP). Using three orthogonal high-precision position sensors, the D-H parameters of industrial robots can be calibrated online with low cost and high precision by the calibration algorithm of D-H parameters of industrial machines and precise iterative measurement of special four ball calibration table. Compared the result of measurement with laser tracker, the maximum En value of each measurement point is 0.63, and the comparison result is satisfactory.
Abstract:
Aiming at the problem of pipe thickness measurement under high temperature in petrochemical industry, this paper investigates the influencing factors of the method of high temperature pipe thickness measurement based on ultrasonic spectrum, and develops a set of ultrasonic thickness measurement simulation system. In the simulation experiment, the influence of different thickness, different material, different noise level and different temperature on the measurement results are discussed. In addition, the influence of different thickness measurement methods on the measurement of pipe thickness is compared. The experimental results show that the system may simulate the high temperature ultrasonic thickness measuring system well and realize the measurement of the high temperature pipe thickness.
Abstract:
In the activities of metrology information management, the institutions have accumulated a large amount of data through the process of certificate and report digitizing. These data are generally used to verify that the metrology parameter of instruments which be calibrated is conform to legal requirements. The potential value of these data is often be ignored. This paper is concerned with mining the potential value of these metrology big data for value-added customer services. Classification analysis, cluster analysis and association analysis method are applied in this paper. It is be proved that data mining is an efficient method for digging metrology big data and the application of data mining can result a mount of social and economic benefits.
Abstract:
At present, Wearable ECG monitoring equipment is lack of special metrology technology regulation. Based on the relevant standards and metrology technology methods of traditional ECG medical equipment, this paper studies the performance evaluation method of Wearable ECG monitoring equipment. Six types of Wearable ECG monitoring and measuring devices from different manufacturers are measured by using Wearable ECG simulator, and the performance evaluation method of these devices is explored. The results show that the accuracy of the main performance parameters of the Wearable ECG monitoring equipment can be evaluated to a certain extent through the above ways, and the traceability of some parameters can be realized.
Abstract:
Heat meters as an important measurement instrument and basis for heat measurement trade settlement, Must ensure the accuracy and long-term reliability of measurement, After the domestic heat meter put into the market, the quality question frequently appears, the part has been replaced by the import product, Although there are many problems are due to long-term stability, It is called durability test, This study aims to establish a study based on durability test for heat meters, The test method is the study of 4000 variable temperature test, Innovative heat meter test method for durability testing, Improving the quality level of heat meter products in China.
Abstract:
A QuEChERS sample pretreatment method coupled with gas chromatography-tandem mass spectrometry was established to determine 30 pesticide residues in Brassica oleracea. The result showed that the method appeared to be a good linear relationship for 30 pesticides in the concentration ranges of 50~250 μg/L, with correlation coefficients($r^2 $) between 0.9966 and 0.9994. The average recoveries of this method were in the range of 77.46%~114.92% with the extended uncertainty between ±0.0098 and ±0.0606. It provides a theoretical basis for determining the results near the critical point of the maximum residue in B. oleracea.
Abstract:
In optical measurement, it is often affected by the low signal-to-noise ratio(SNR), which increases the uncertainty of measurement results. The measurement of the bidirectional reflectance distribution function (BRDF) in the near-infrared is particularly vulnerable to environmental interference due to the weak infrared signal. The signal-to-noise ratio problem of optical measurement systems generally arises from detection systems. For infrared measurement systems, choppers and lock-in amplifiers are often used for weak signal measurement, but noise problems are also introduced at the same time. Therefore, this article focuses on the SNR of BRDF measurement in the near-infrared, aiming at the detector, chopper and lock-in amplifier, analyzing the source of noise, and proposing suppression methods and optimization measures to improve the signal-to-noise ratio. The optimized measurement system has improved anti-noise ability compared with that before optimization, and the repeatability has been increased from 2.1% to 1.6%.
Abstract:
In order to solve the problem of voltage conversion accuracy deterioration caused by transformer interturn capacitance, the influence of parasitic capacitance of transformer winding on transformer output misalignment is theoretically derived and analyzed, putting forward the method of eliminating or adjusting parasitic capacitance influencing factor and resonant frequency point by combining theoretical analysis with circuit simulation, and also the equivalent negative capacitance generation circuit are proposed. The output comparison test of equal turn ration transformer before and after improvement is carried out, which verifies the correct feasibility of the method and which have good suggestion and application values.
Abstract:
To accurately evaluate the uncertainty of the calibration factor of the β-ray dosemeter, a traceable thin window ionization chamber was used to measure the reference dose rate at the reference position of the β-ray radiation field, and then the β-ray dosemeter was placed in the same position for measurement to obtain the indicated value. The calibration factor of the β-ray dosemeter was obtained, and the uncertainty of the calibration factor was evaluated. The main sources of uncertainty include the uniformity of the reference radiation field, the uniformity of the position in the measurement process of the substitution method, and the statistical standard deviation of the indicated value. The results show that in the calibration process, the uncertainty of the calibration factor can be improved by improving the uniformity of the reference radiation field and the uniformity of the reference position.
, Available online  , doi: 10.12338/j.issn.2096-9015.2020.0166
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Abstract:
In mmwave technology a low frequency is always multiplied to generate a much higher frequency. Phase noise will be also increased and phase noise test will be more important in mmwave band. It is limited with spectrum analyzer method because of some reasons. And phase noise analyzer can only cover up to 50 GHz in a single unit. After the basic introduction of phase noise test technology in mmwave band two external mixer method is provided. Result shows that with this method we can get a stable test result.