Abstract: Carbonaceous aerosols have a significant impact on climate change and environmental pollution. The accurate measurement of carbonaceous aerosols can effectively reduce the uncertainty of aerosol radiative forcing estimation and atmospheric source apportionment, and further provide scientific support for government control policies to address climate change and reduction of source emission. This paper reviews the measurement methods and influencing factors of carbonaceous aerosols at home and abroad, focuses on the research progress and limitations of existing standard protocols and reference materials, and points out the gaps and needs in the development of carbonaceous aerosol reference materials. On this basis, this paper further proposes future research directions and difficulties from various aspects, including the traceability of reference materials, the selection of representative species of organic carbon and elemental carbon, the configuration of OC/EC mixed reference materials, and the impact of carbonate carbon, which provide references for the in-depth research of carbonaceous aerosol reference materials.
Abstract: Hexabromocyclododecanes (HBCDs) is a mass-produced and widely used brominated flame retardant, which is a new type of persistent organic pollutant. HBCDs are widely distributed in the environment and their contents span a wide range, and accurate analysis and determination of their contents in environmental media are of great significance for environmental pollution control. This paper summarized the pollution distribution of HBCDs in sediments across China. Based on literature research, the key techniques of pretreatment, separation, and detection of HBCDs in sediments and related matrices were compared and analyzed. In addition, by investigating the source of HBCDs reference materials, the traceability of HBCDs for accurate quantification was discussed, and the future measurement and monitoring work of HBCDs was put forward.
Abstract: Arsenic and antimony are typical anionic pollutants, and with the development of arsenic-antimony mineral resources, as well as the abuse of arsenic and antimony-containing pesticides and additives, arsenic and antimony pollution incidents in the environment often occur. The development of speciation analysis techniques for arsenic and antimony in environmental media is of great significance for the environmental regulation and pollution prevention of arsenic and antimony pollution. In this paper, the developed speciation analysis techniques for arsenic and antimony were reviewed, with particular attention to the development of current on-site speciation analysis techniques,
Abstract: Quantitative nuclear magnetic resonance (qNMR) is a potential primary method for determining the purity of organic compounds, which can establish the metrological traceability of the vast majority of organic compounds. The principles, advantages, and challenges of the recent approaches of qNMR methods that can effectively separate the impurity peaks from the quantitative peaks of the analytes are reviewed, including the combination of high-performance liquid chromatography (HPLC) and qNMR, HPLC-qNMR with bi-deuterated mobile phase, HPLC-single-signal-suppression qNMR with single-deuterated mobile phase, HPLC-double-signal-suppression qNMR, internal standard recovery correction (ISRC)-HPLC-qNMR, internal standard correction(ISC)-HPLC-qNMR, extended internal standard method for qNMR assisted by chromatography (EIC), peptide impurity corrected qNMR (PICqNMR), two-dimensional NMR: quantitative heteronuclear single quantum correlation NMR (qHSQC), and HPLC-qNMR-HPLC. These methods can reduce the potential systematic errors in qNMR, improve the accuracy of the results, and expand the application of qNMR as a metrological potential primary method and a routine analysis method.
Abstract: Water-soluble ions are the main components of atmospheric particulate matter, and play a key role in the source appointment of particulate matters. This paper reviews offline and online monitoring methods, instruments and measurement standards for water-soluble ions in atmospheric particulate matter, analyzes the current status of offline and online monitoring measurement technologies and protocols, and presents the problems such as the lack of reference materials in the pre-treatment of filter membrane samples in offline monitoring, and the large number of gaps in measurement methods, reference materials and standard devices in online monitoring. In view of the above problems, the development direction of metrology research is prospected.
Abstract: Proton radiotherapy has gradually become a precision radiotherapy technique owing to the characteristic of Bragg Peak on the depth-dose distribution. This paper introduces the details of three proton beam reference dosimetry methods as well as the corresponding limitations in clinical proton modalities. Further discussions on the correction terms and improvement methods of measurements combined with Monte Carlo techniques have been proposed. Finally, the state-of-the-art determination on microdosimetry of proton beams has been summarized, which provides a reference for research on proton beam water absorption dose measurement.
Abstract: As an essential rehabilitation physiotherapy equipment and non-invasive neuromodulation technology, repetitive Transcranial Magnetic Stimulation (rTMS) plays a vital role in the treatment of psychiatric diseases and brain function modulation. Since rTMS uses the pulsed magnetic field to act directly on the human brain, the magnetic induction intensity and output frequency of the pulsed magnetic field determine the safety and effectiveness of stimulation. Starting with reviewing the development of TMS, the technical principle of rTMS was introduced, and the research path of its measurement was described in detail. In this paper, the distribution of pulsed magnetic field generated by a typical stimulation coil was obtained by simulation, which could specify the approximate position of the maximum value point of magnetic induction intensity in grey matter. The feasibility of the electromagnetic induction method for measuring pulsed magnetic field has been demonstrated through research and trial production of electromagnetic induction coils and experiments. The measurement method developed in this paper can not only be used for the detection of rTMS in use but also serve cutting-edge scientific research fields such as brain function modulation, contributing to the implementation of the Healthy China 2030 strategy.
Abstract: As one of the most widely used industrial compounds in the world, Bisphenol A can be used in the production and manufacture of a variety of polymer materials and is ubiquitous in actual production and daily life. Bisphenol A is also a typical environmental endocrine disruptor, which can lead to metabolic and reproductive disorders in humans and can cause various cancers in severe cases. With the increasing emphasis on the addition of bisphenol A in various industries in recent years, the detection methods of bisphenol A have also been continuously innovated. This paper reviews the advanced detection technologies and methods at home and abroad, sorts out and summarizes the research progress of bisphenol A detection, and puts forward the prospects for the development of bisphenol A detection in the future.
Abstract: Based on the spatial geometric analysis, a mathematical model for measuring the kingpin angle was established, the detection mechanism of the measuring positioning parameters was studied, and a verification device for four-wheel alignment was designed. The device uses the spherical hinge structure to make the simulated kingpin backward and inward tilt independently, avoiding errors caused by interference in the synthetic motion. The dual-axis inclination angle sensor is used to realize the accurate measurement of the positioning parameters. The finite element modal analysis of the device was carried out by ANSYS software, the results showed that the stiffness and the inherent frequency and vibration model of the first six orders meet the requirements of the structure. The zero position error of the kingpin angle and the error of each wheel location parameters obtained from the test met the requirements of the calibration specification, which verified the feasibility of the device.
Abstract: The number of microorganisms in domestic drinking water is one of the important monitoring items for water quality safety. To verify the understanding of domestic testing laboratories for the measurement of Escherichia coli (E.coli) in drinking water, the National Institute of Metrology (NIM) developed a proficiency testing sample for the quantification of E.coli in drinking water and carried out a proficiency testing to assess the ability of participating laboratories. Complied with the national standard GB/T 5750.12-2006 Standard examination methods for drinking water - Microbiological parameters, 11 laboratories participated in the proficiency testing and determined the CFU or MPN value of E.coli in lyophilized samples reconstituted in sterile water by using the filtration membrane method and enzyme substrate method. The statistics indicated that the results of all the participating laboratories are satisfactory. The E.coli quantitative proficiency testing samples are homogeneous and stable, which can meet the requirement of proficiency testing for quantification of E.coli in drinking water and reflect the ability of participating laboratories.
Abstract: Pump-driven loop heat pipe energy recovery device is an air conditioning energy recovery device, which integrates the advantages of intermediate heat medium and loop heat pipe heat exchangers and is suitable for complex pipeline layouts. In order to study the performance of the device, an experimental system for the pump-driven loop heat pipe energy recovery device was set up, and three performance evaluation coefficients, heat exchange, temperature efficiency, and performance coefficient were proposed, and the effects of four factors on the performance of the device, including temperature difference ΔT, mass flow rate m, heat exchange area A,and working medium, were considered. By testing the values of heat exchange, temperature efficiency, performance coefficient under different temperature differences, mass flow rate, and exchange area, the relationship between them and optimal operation scheme were obtained, which provided guidance and reference for the design and operation of such devices.