Abstract: A method for obtaining regenerated seedlings of Brassica campestris L. ssp. chinensis from embryonic tip tissues, including the following steps. A seed is inoculated to a germination medium for dark culture for 60 h. The testa, root tip, two cotyledons and middle growing point of the resultant germinated seed are removed, and an embryonic tip with a length of 3-5 mm is retained as an explant. The explant is sequentially subjected to low-temperature pre-culture in a pre-culture medium for 36 h, room-temperature shaking culture in a liquid bud induction culture medium for 10 min, and bud induction culture in a bud induction culture medium for 20 d. A regenerated plant with 5-6 leaves is transferred to a rooting medium for rooting culture for about 2 weeks, and a well-rooted plant is collected, and subjected to hardening and transplantation into a filed.

Abstract: A method and an apparatus for acquiring induced polarization parameters by using a spread spectrum signal, a medium and a device are provided, where the method includes: sending a spread spectrum signal to a detection object and acquiring time sequence data of the spread spectrum signal; acquiring a frequency spectrum value of each main frequency in the spread spectrum signal, and obtaining a normalized complex value of each main frequency based on the frequency spectrum value of each main frequency; obtaining a frequency value of each combined frequency in the spread spectrum signal; calculating a normalized complex value of each combined frequency according to the normalized complex value of each main frequency; and calculating induced polarization parameters of all combined frequencies according to frequency values of all combined frequencies and normalized complex values of all combined frequencies.

Abstract: A magnetotelluric impedance estimation method is provided, belonging to the field of exploration. The method specifically includes the following steps: Step 1, performing Fourier transform on electromagnetic time series data of a plurality of electromagnetic field components to obtain a frequency spectrum array corresponding to each of electromagnetic field components; Step 2, identifying an interference frequency of each of electromagnetic field components according to the frequency spectrum array; Step 3, merging the interference frequency and a deviation value; Step 4, attenuating the frequency spectrum array using the merged interference frequency and deviation value; Step 5, recovering the electromagnetic time series data using the attenuated frequency spectrum array, so as to obtain a transform result; and Step 6, performing magnetotelluric impedance estimation according to the transform result. By the scheme disclosed, the adaptability and accuracy of magnetotelluric impedance estimation are improved.