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With vitamin A acetate as raw material, ethylenediamine retinyl Schiff base salts coordinated with rare earth ion La3+, Ce3+ were synthesized, and the structure of the products was characterized by FT-IR and Raman spectra. The electromagnetic parameters in the frequency range of 2-18 GHz were measured by microwave vector network analyzer, its reflectivity was calculated, and the main factors and mechanism that affect the wave-absorbing performance of rare retinyl Schiff base salts were discussed. The results show that the coordination bond is formed by the rare earth ions and Schiff base. The reflectivity of Schiff base coordinated with La3+ ion is –16 dB at 12.9 GHz (bandwidth with reflectivity better than –10 dB is 3.1 GHz), the reflectivity of Schiff base coordinated with Ce3+ ion is –18.8 dB at 12.7 GHz (bandwidth with reflectivity better than –10 dB is 3.4 GHz). Microwave absorption performances of the both are superior to the wave-absorbing performance of Schiff base coordinated with non-rare earth ions.

In view of problem that existing hydraulic support life estimation method rarely consider continuous performance decline of hydraulic support in use process and leads to great error, a residual life estimation method of components of hydraulic support in service was proposed. Components S -N curve was obtained by correcting material S -N curve through introduction of surface coefficient, structural size coefficient and welding impact coefficient. Then the components S -N curve was used for life estimation according to cumulative damage theory, residual damage capacity and stress spectrum. Multi-level fuzzy evaluation method was used to evaluate the state of hydraulic support roof beam, and overall life coefficient was multiplied by the estimated life to get the residual life of the components of hydraulic support in service. The experimental results show that the estimation error of the proposed method is 3.52% and the precision is high.