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Single energy system can not give full play to its advantages and can not better meet the characteristics of large random load fluctuation in tractor operation. The energy system of hybrid tractor based on hydrogen fuel cell, power cell and supercapacitor in parallel is designed in this paper. For the system, a hierarchical decoupling control energy management strategy based on Haar wavelet and logical threshold rules was designed to realize the hierarchical decoupling of high frequency signal, sub-high frequency signal and steady state signal, and to distribute the power signal after decoupling. The model in loop simulation test was carried out, and the results showed that: Compared with the power following control strategy and fuzzy control strategy, the average efficiency of hydrogen fuel cell by the hierarchical decoupling control strategy established in this paper increases by 2.87% and 1.2% respectively in the experimental cycle. The vehicle equivalent hydrogen consumption decreased by 17.06% and 5.41%, respectively.

With the rapid development of China’s agricultural economy, the domestic research on full-power shift transmissions is still immature. In view of the problem of poor transmission shift quality, this paper proposes a tractor full-power shift transmission shifting coordination section law. A transmission dynamics model based on Matlab/Simulink was simulated and analyzed. The results show that the quality of shifting only is better than that of only changing sections, and the quality of shifting after shifting first is worse than that of shifting after shifting first. And selected only the shift and first shift after the two laws of the section, the shortening of the clutch engagement time during the shift only, the impact degree is reduced over time, the first decrease is increased, and the sliding friction work is increased. The change of time between the shift and the transition period, the impact is reduced with time, and the sliding friction work is increased.

Effects of Y2O3 on the oxidation behavior of 304 SS with coating by laser remelting after exposed to 290 °C water containing 3 ppm O2 for 72 h were investigated. It was found that the corrosion behavior of remelted layer on 304 SS with the addition of Y2O3 was completely different from that of 304 SS and remelted layer on 304 SS without the addition of Y2O3. More Cr2O3 hematite oxides were formed around strengthening phase near the Y2O3 particles. With increasing exposure time, a little number of Fe3O4 spinel oxides were continuing formed on the surface outside the Mn/Si enrichment area. The growth of Fe3O4 spinel oxides were hindered because of the massive Cr2O3 hematite oxides around the Y2O3 particles. Some small Fe3O4 spinel oxides were formed. Finally, the types of oxide film formed on the surface of the remelted layer with the addition of Y2O3 were mainly Cr2O3 hematite oxides and a few of fine FeCr2O4 spinel oxides. The addition of Y2O3 in laser remelting layer can obviously change the corrosion behavior of 304 SS exposed to high temperature water and the related mechanisms are also discussed.

This paper presents an FFT (fast Fourier transform) analytical method for the study of surface structures fabricated by laser interference lithography (LIL). In the work, the FFT analytical method combined with Gaussian fitting is used to determine the periods and pattern distributions of surface structures from frequency spectra. For LIL, the processing parameters of incident and azimuth angles can be obtained corresponding to the period and pattern distribution. This work facilitates the detection of micro- and nano-structures, the analysis of pattern distribution in engineering, and the processing error analysis of LIL.