Abstract: Disclosed is a two-stage frequency selection method and device for microwave frequency sweep data. The method includes: acquiring microwave frequency sweep data; performing frequency selection on the microwave frequency sweep data by using a random forest-recursive feature elimination algorithm, taking a preset parameter in the random forest-recursive feature elimination algorithm as a hyper-parameter, changing the value of the hyper-parameter, and generating a series of candidate frequency subsets within different frequencies; building prediction models on the basis of the frequency sweep data corresponding to the candidate frequency subsets of different frequencies; evaluating the performance of each prediction model by means of 10 fold cross validation, and calculating evaluation index values of model performance; and taking the evaluation indexes as a voting basis, and selecting an optimal frequency subset by using a majority voting method.

Abstract: A pneumatic pollination device and a method for hybrid rice seed production with a large row ratio are provided. The pneumatic pollination device includes a pneumatic pollination component, a controller, a lifting adjustment component and a four-wheel power chassis. The pneumatic pollination component is mounted at the front part of the four-wheel power chassis through the lifting adjusting component, and the controller is mounted at the upper part of the four-wheel power chassis. The airflow of each pollination pipe respectively acts on the spike part of the male parent row of corresponding hybrid rice, so that the male pollen is separated from stamens and floats to the female compartment. The airflow velocities of the pollination pipes of respective male parent rows are different to ensure that the pollen is conveyed to the main female parent action region.