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Objective The insufficient toe load of the fastener elastic rod will induce loosening of the surrounding fasteners, aggravate the dynamic response between wheels and rails, affecting the service life of the track components. Compared with the missing and breaking of the fastener elastic rod, fastener elastic rod loosening is more difficult to be spotted by routine manual inspection, so the toe load detection method of the fastener elastic rods needs to be studied. Method Taking WJ-7 fastener elastic rod of high-speed railway as an example, a refined model of fastener system is established, the modal characteristics of fastener elastic rod under different toe load states are analyzed, corresponding relationship between the toe load of fastener elastic rod and the natural frequency is obtained, and a rapid non-destructive testing method for calculating the toe load by testing the modal frequency of elastic rod is proposed accordingly. The high-speed railway line at the track test base of a State Key Laboratory is selected as the test site, and the test verification of the detection method is carried out. Result & Conclusion Under different toe load states, the 1st modal shape characteristics of elastic rods all manifest as vertical vibration and torsion on both side legs of the elastic rod. The maximum absolute value of the difference ratio between the simulation value and the measured value of the elastic rod 1st order natural frequency is 3.24%, so the test method can be considered as effective.

Astragali radix (AR) is not only a traditional Chinese medicine, but also a good tonic that is often consumed by people and has good disease prevention and health care effects. Due to the complex composition of AR and the interaction of different chemical components, it presents challenges in quality control. In this study, a gradient elution tower plate theory suitable for gradient elution was firstly established, followed by HPLC analysis combined with quantitative analysis of multi-components by single marker (QAMS) and multi-markers assay by monolinear method (MAML) for accurate content determination of the indicator components (calycosin-7-O-β- D -glucoside and formononetin) in AR. FTIR and DSC are also used to collect the fingerprints of AR and quantize them to obtain the structural information inside the substance. The established fingerprints were evaluated qualitatively and quantitatively using the systematic quantitative fingerprint method (SQFM) and chemometrics, and the characteristic parameters of the three fingerprints were investigated in relation to the macro-quantitative similarity (Pm) using the Pearson correlation analysis. Finally, the coefficient of variation weighted mean method (CVWMM) was used to synthesize the evaluation results and establish the HPLC–FTIR–DSC quality control system, which is more objective and reasonable. The results showed that the calculated results of QAMS and MAML were basically consistent with those of an external standard method. Pm had the function of representing the overall fingerprint information of the samples for quantitative evaluation. SQFM combined with CVWMM successfully differentiated the quality grades of 35 batches of AR samples. The combination of the three analytical methods resulted in the effective improvement of the quality evaluation of AR compared with a single method in terms of accuracy and completeness. This study provides a novel and comprehensive strategy for quality consistency evaluation of AR. [ABSTRACT FROM AUTHOR]