Abstract: A comprehensive two-dimensional gas chromatograph, comprising a sample injector, a primary dimension column, a two-position three-way valve, a secondary dimension column, a three-way tube, a heating oven and a detector, wherein an inlet end(s) of the sample injector is connected to a carrier gas line and as well to a sample line, and an outlet end thereof is connected to a first end of the primary dimension column, a second end of the primary dimension column is connected to a first branch of the three-way tube, a second branch of the T-union is connected to a first end of the secondary dimension column, a second end of the secondary dimension column is connected to an inlet of the detector, a third branch of the three-way tube is connected to a gas inlet of the two-position three-way valve, and a first gas outlet of the two-position three-way valve is connected to the carrier gas line.

Abstract: Disclosed are a display panel and a display screen. The display panel includes a plurality of display modules and a cabinet. The plurality of display modules are distributed in a matrix and are fixed in front of the cabinet. The cabinet is provided with two display module openings and a power supply assembly opening. A protective cover plate is installed in front of the cabinet to cover the power supply assembly opening and form a power supply assembly cavity behind the cabinet, which is configured to install a power supply assembly. Two module opening cover plates are installed behind the cabinet to cover the two display module openings in a one-to-one correspondence.

Abstract: Disclosed are a display panel and a display screen. The display panel includes a plurality of display modules and a cabinet. The plurality of display modules are distributed in a matrix and are fixed in front of the cabinet. The cabinet is provided with two display module openings and a power supply assembly opening. A protective cover plate is installed in front of the cabinet to cover the power supply assembly opening and form a power supply assembly cavity behind the cabinet, which is configured to install a power supply assembly. Two module opening cover plates are installed behind the cabinet to cover the two display module openings in a one-to-one correspondence.