Abstract: A sowing device changes a depth of wheat sowing includes an external skeleton, where one side of the external skeleton is fixedly connected with a connection part for articulated with a tractor; a main board slidably connected to an interior of the external skeleton and a seeding unit below the main board; a support frame fixedly connected to the main board; a plow blade for slotting land rotatably connected to a bottom of the support frame; a rotary roller below the external skeleton and rotationally connected thereto. The main board is moved downwards to drive a straight toothed plate fixedly connected to the main board to move downwards; the straight toothed plate is moved upwards through a meshing effect of a gear to cause L-shaped toothed plate to move upwards to squeeze a horizontal plate to move upwards.

Abstract: A cutting tool for machining titanium alloy or superalloy includes a Me-B-N coating. The Me-B-N coating is Me1-B-N; Me1 is one or more selected from transition metal elements Hf, V, Nb, Ta and Mo, and the atomic percentage of each element is: Me1: 8-40%, B: 15-60%, and N: 10-65%; and the Me-B-N coating includes Me1Nx phase and BN phase; or, the Me-B-N coating is Me1-Me2-B-N, Me1 is one or more selected from transition metal elements Hf, V, Nb, Ta and Mo; Me2 is one or more selected from transition metal elements Ti, Zr, Cr, and W; and the atomic percentage of each element is: Me1: 4-36%, Me2: 4-36%, B: 15-60%, and N: 10-65%; and the Me-B-N coating includes Me1Nx phase, Me2Nx phase and BN phase.

Abstract: A cutting tool, including a silicon nitride (Si3N4) ceramic substrate, and a diamond film coated on the surface of the Si3N4 ceramic substrate. The diamond film has a thickness of 7-12 ?m. The cutting tool includes a tool nose, a blade, and a handle. The blade has a rake angle ? of 5-15°, a clearance angle ? of 10-14°, and a helix angle of 15-45°. The blade includes four cutting edges.