Abstract: A tool attachment device for assisting a power tool in performing nailing includes a shell assembly, a rocker, a connection device, a driving wheel, and a transmission assembly. A side of the shell assembly is formed with a hole passage. The rocker is partially placed in the hole passage and is rotatable in the hole passage. The connection device is connected to the rocker and rotates synchronously with the rocker. Nail feeding structures are formed on the driving wheel along a circumferential direction of the driving wheel. The transmission assembly is connected to the driving wheel and the connection device and is configured to drive the driving wheel to rotate unidirectionally. The transmission assembly is disposed between the connection device and the driving wheel.

Abstract: A nail gun includes: a housing; an accessory box for accommodating a fastener and at least partially connected to the housing; and a power output portion for outputting a striking force to the fastener; and an operating member triggered to have at least a first position and a second position, where the nail gun has a maximum desired penetration depth when the operating member is operated to the first position, and the nail gun has a minimum desired penetration depth when the operating member is operated to the second position; and when the operating member switches from the first position to the second position, an angle by which the operating member rotates about a first straight line is less than or equal to 360°.

Abstract: This application provides a method for issuing a digital certificate performed by a digital certificate issuing center that includes a public-private key generation module and an authentication module. The method includes: receiving a public-private key request from a node in a blockchain network; generating a public key and a private key of the node by using the public-private key generation module, and transmitting the public and private keys to the node; receiving the public key of the node and registration information of the node, and authenticating the registration information by using the authentication module; and generating, in accordance with a determination that the authentication succeeds, a digital certificate of the node by using the authentication module, and transmitting the digital certificate to the node. The embodiments of this application can improve the probative value of an issued digital certificate, thereby improving the security of data exchange in a blockchain network.

Abstract: The invention disclosed a compound of general formula (I), a single stereoisomer thereof, a mixture of stereoisomers thereof, and a prodrug, pharmaceutically acceptable salt and metabolite thereof, X1, X2, X3, X4, R1, R2, x, y and z being as defined in the present invention.

Abstract: The invention disclosed a compound of general formula (I), a single stereoisomer thereof, a mixture of stereoisomers thereof, and a prodrug, pharmaceutically acceptable salt and metabolite thereof, X1, X2, X3, X4, R1, R2, x, y and z being as defined in the present invention.