Abstract: The invention relates to the technical field of oil and gas field development, in particular to a staged multi-cluster fracturing sliding sleeve system and method based on smart key label. The system includes at least one multi-cluster sliding correspondingly placed in each fracturing stage, an end sliding sleeve, and a smart key label. The method includes: step S1, performing fracturing stage by stage from a first stage to a last stage, placing the smart key label through a wellhead and pumping the smart key label to the target fracturing stage; step S2, opening the multi-cluster sliding sleeves of the current fracturing stage one by one through the smart key label, and finally blocking the smart key label in the end sliding sleeve when the multi-cluster sliding sleeve and the end sliding sleeve of the current fracturing stage are opened; and step S3, repeating the steps S1 and S2 until the fracturing operations of all the stages are completed.

Abstract: A time threshold model creation method and a time threshold model creation system based on an autonomous braking system are provided. The method includes the steps of: obtaining braking data about a target vehicle; creating a three-dimensional space in accordance with a braking time, a speed of the target vehicle, and a relative speed, and obtaining a point cloud of the braking data in the three-dimensional space; dividing a two-dimensional plane defined by the speed of the target vehicle and the relative speed into a plurality of statistical regions, and calculating a probability in each statistical region to obtain a fitted probability distribution curve; calculating a time threshold in each statistical region in accordance with the fitted probability distribution curve; and obtaining a target curve surface of the time thresholds in accordance with the distribution of the time threshold in each statistical region in the three-dimensional space.

Abstract: The present invention relates to a portable electronic device and an external keyboard thereof. The portable electronic device comprises a first port comprising a circular earphone plug and a keyboard plug. The external keyboard comprises a main body, a keyboard array and a second port. The keyboard array is disposed on the main body and comprises a plurality of scan signal lines. The second port is electrically coupled to the scan signal lines of the keyboard array, and is capable of inserting into the first port of the portable electronic device so as to electrically couple to the keyboard plug. Therefore, the external keyboard can be connected to an earphone jack in a plug-and-play fashion without necessarity to add a new port such that the external keyboard is convenient to use and carry and can be freely rotated in any angle.

Abstract: The present invention relates to a portable electronic device and an external keyboard thereof. The portable electronic device comprises a first port comprising a circular earphone plug and a keyboard plug. The external keyboard comprises a main body, a keyboard array and a second port. The keyboard array is disposed on the main body and comprises a plurality of scan signal lines. The second port is electrically coupled to the scan signal lines of the keyboard array, and is capable of inserting into the first port of the portable electronic device so as to electrically couple to the keyboard plug. Therefore, the external keyboard can be connected to an earphone jack in a plug-and-play fashion without necessarity to add a new port such that the external keyboard is convenient to use and carry and can be freely rotated in any angle.