Abstract: Methods, devices, and storage media for performing annotation using an interactive white board are described. An example method includes displaying a first interface on a touch sensitive display screen of the interactive white board; receiving a first movement operation of a first or second touch object on the first interface; adding a first annotation layer, and adding handwriting or erasing handwriting on the first annotation layer; receiving second movement operation of the first or second touch object; adding handwriting or erasing corresponding handwriting on the first annotation layer based on the second movement operation; receiving first clicking operation of a third touch object on the first annotation layer; and updating a display content of the first interface based on a target clicked by the first clicking operation.

Abstract: Methods, devices, and storage media for performing annotations using an interactive white board are disclosed. An example method includes displaying a first interface on a touch sensitive display screen of the interactive white board; receiving a first movement operation of a first or second touch object on the first interface; adding a first annotation layer, and adding handwriting or erasing handwriting on the first annotation layer; receiving second movement operation of the first or second touch object; adding handwriting or erasing corresponding handwriting on the first annotation layer based on the second movement operation; receiving first clicking operation of a third touch object on the first annotation layer; and updating a display content of the first interface based on a target clicked by the first clicking operation.

Abstract: A lock assembly includes a driving member, a locking member, and a latch. The driving member includes a connection end, and a driving end movable with respect to the connection end. The connection end is arranged on a fastener. The locking member is rotatably arranged on a carrier through a first rotation shaft. The driving end is rotatably connected to the locking member through a second rotation shaft. The locking member includes a hook. The latch is arranged on the fastener. The hook is capable of hooking the latch. The driving end is configured to capable of driving the hook to disengage from the latch, and driving the carrier to rotate with respect to the fastener, or the driving end is configured to drive the hook to hook the latch so that the carrier is secured to the fastener.

Abstract: A lock assembly includes a driving member, a locking member, and a latch. The driving member includes a connection end, and a driving end movable with respect to the connection end. The connection end is arranged on a fastener. The locking member is rotatably arranged on a carrier through a first rotation shaft. The driving end is rotatably connected to the locking member through a second rotation shaft. The locking member includes a hook. The latch is arranged on the fastener. The hook is capable of hooking the latch. The driving end is configured to capable of driving the hook to disengage from the latch, and driving the carrier to rotate with respect to the fastener, or the driving end is configured to drive the hook to hook the latch so that the carrier is secured to the fastener.

Abstract: The present invention relates to electronic technology field, and more particularly to CRT and projection system. A low power laser CRT based on parallel flow electron gun comprises a vacuum tube, a laser panel provided at one end of the vacuum tube and an electron gun provided at the opposing end. The electron gun adopts a parallel flow electron gun, wherein the parallel flow electron gun comprises a negative electrode, a G1 electrode and a control electrode, wherein the control electrode is connected to an electron beam current control system. The electron gun of the present invention adopts parallel flow electron gun to emit electron beam, so that the laser panel has even current density distribution so as to average the power consumption of laser panel to reduce the energy that is converted to heat.