Abstract: A dual polarization antenna that includes a conductor and two dipoles. The conductor has four radiation arms, each radiation arm forms a branch of the conductor, and two adjacent radiation arms are connected by a connection bridge. The two dipoles are arranged in a cross manner to form four sectors, one radiation arm is arranged in each sector, and the connection bridge is disposed above or below the dipole between the two radiation arms connected by the connection bridge.

Abstract: A fluidized catalytic conversion method for maximizing the production of propylene includes the steps of: 1) contacting a heavy feedstock oil with a catalytic conversion catalyst having a temperature of 650° C. or higher for reaction; 2) contacting a hydrocarbon oil feedstock having an olefin content of 50 wt % or more with the catalytic conversion catalyst after the reaction of step 1); 3) separating a first catalytic cracking distillate oil and a second catalytic cracking distillate oil from the resulting reaction products; 4) separating an olefin-rich stream from the first catalytic cracking distillate oil; and 5) recycling the olefin-rich stream. The method can effectively improve the yield of propylene and realize an effective utilization of petroleum resources.

Abstract: A fluidized catalytic conversion method for producing light olefins includes the following steps: 1) introducing an olefin-rich feedstock into a fluidized catalytic conversion reactor, and contacting with a catalyst having a temperature of 650° C. or higher for reaction; 2) separating the reaction product vapor obtained by the reaction to obtain a stream comprising C5+ olefins; and 3) recycling at least a part of the stream comprising C5+ olefins to step 1) for further reaction. The fluidized catalytic conversion method can effectively improve the yield of light olefins, improve the selectivity and improve the ethylene/propylene ratio of the product.