Abstract: Provided are a new vertical cavity surface emitting laser structure and a manufacturing method thereof. The structure includes a substrate layer, a lower N-type DBR, an active region, an upper N-type DBR and a mixed dielectric DBR sequentially arranged from bottom to top, where a second-class tunnel junction is arranged on one side of the active region close to the upper N-type DBR, where the second-class tunnel junction is embedded in a bottom of the upper N-type DBR and surrounded by the upper N-type DBR, and the substrate layer, the lower N-type DBR, the active region, the upper N-type DBR, the mixed dielectric DBR and the second-class tunnel junction are all coaxial elliptical cylinders; negative electrodes are arranged on the lower N-type DBR, and positive electrodes are arranged on the upper N-type DBRs substrate layer.

Abstract: A push-pull force control method for a horizontal directional drilling machine with the following steps is provided. According to a correspondence relationship between a motor displacement and a maximum push-pull force of a drilling machine, the motor displacement is first adjusted, so that the required push-pull force can be obtained through the adjustment of the subsequent steps. Then, an oil feeding pressure of the motor is controlled according to a relationship between the push-pull force and the working pressure difference of the motor. Finally, the push-pull force of the motor is controlled in real time according to the oil feeding pressure of the motor to be equal to the required push-pull force value.

Abstract: A push-pull force control method for a horizontal directional drilling machine and a horizontal directional drilling machine are provided. The control method includes: adjusting a working displacement of a motor to enable a maximum push-pull force Fmax corresponding to the working displacement to be greater than a set push-pull force Ft; calculating a working pressure difference ?P of the motor according to the set push-pull force Ft; calculating a working pressure required by the motor according to the working pressure difference ?P and a collected first oil return back pressure of the motor; and adjusting an oil feeding pressure of the motor to enable the oil feeding pressure of the motor to be equal to the working pressure required by the motor. The method accurately and fast controls the push-pull force of the horizontal directional drilling machine.