Abstract: A display panel, a method for gamma correction of a display panel and a device for gamma correction of a display panel are provided according to the present disclosure. The method for gamma correction includes: determining a target grayscale interval where the to-be-displayed grayscale is located and a target sub-frame corresponding to the target grayscale interval based on a to-be-displayed grayscale; correcting a gamma of the target grayscale interval including: in each of sub-frames other than the target sub-frame, providing a grayscale interval data signal to the sub-pixel, and in the target sub-frame, providing a data signal to the sub-pixel, and correcting based on collected optical data to obtain a calibration data signal. Further, a refresh period is divided into at least two sub-frames for gamma correction, and different sub-frames correspond to different grayscale intervals.

Abstract: A dust-collecting cover for an electric circular saw includes a dust-collecting cover body configured as a cavity structure thereinside. A bottom surface of a cavity is formed with a strip-shaped opening, which is used for a saw blade to pass therethrough. Other surfaces of the cavity are configured as closed structures. An airflow passage is automatically formed in the cavity during operation. A pathway of the airflow passage starts from a part of the rear end of the strip-shaped opening adjacent to saw teeth, to a front end of the strip-shaped opening in an arc shape along the outer edge of the saw blade, then turns upwards and rearwards, and along an upper wall of the cavity, then turns downwards, and stops at a part of the rear end of the strip-shaped opening away from the saw blade. A dust-collecting method is disclosed.

Abstract: An array substrate, a liquid crystal display and a control method thereof are disclosed. The array substrate includes scanning lines, data lines, pixel units, and common lines. Each common line is disposed along a row of pixel units. The array substrate also includes a common voltage supply line, and dual-channel selection switches each having an output terminal connected to a set of common lines, two input terminals connected to a common voltage high level supply line and a common voltage low level supply line respectively to selectively apply a high level or a low level to the common lines, thereby avoiding delay of the common voltage Vcom and the Vcom drift during a display mode and improving the display effect for an image.

Abstract: The present invention discloses a clean method for preparing a D,L-methionine comprising the steps of: preparing a potassium cyanide solution using a crystallized mother solution containing potassium carbonate as an absorbing liquid to absorb hydrocyanic acid, then reacting the potassium cyanide solution with 3-methylthio propionaldehyde and an ammonium bicarbonate solution at 50-150° C. for 3-15 minutes so as to obtain a 5-(?-methylthioethyl)glycolyurea solution, then bring the 5-(?-methylthioethyl)glycolyurea solution to a temperature of 140-220° C. and subjecting to a saponification reaction for 2-5 minutes, after the completion of the saponification, reducing the temperature to 0-40° C., extracting with an organic solvent, neutralizing the water phase with CO2 and crystallizing, then filtering, washing, and drying to obtain an acceptable D,L-methionine product; bring the crystallized D,L-methionine mother solution from filtration to a temperature to 110-160° C.

Abstract: The present invention discloses a clean method for preparing a D,L-methionine comprising the steps of: preparing a potassium cyanide solution using a crystallized mother solution containing potassium carbonate as an absorbing liquid to absorb hydrocyanic acid, then reacting the potassium cyanide solution with 3-methylthio propionaldehyde and an ammonium bicarbonate solution at 50-150° C. for 3-15 minutes so as to obtain a 5-(?-methylthioethyl)glycolyurea solution, then bring the 5-(?-methylthioethyl)glycolyurea solution to a temperature of 140-220° C. and subjecting to a saponification reaction for 2-5 minutes, after the completion of the saponification, reducing the temperature to 0-40° C., extracting with an organic solvent, neutralising the water phase with CO2 and crystallizing, then filtering, washing, and drying to obtain an acceptable D,L-methionine product; bring the crystallized D,L-methionine mother solution from filtration to a temperature to 110-160° C.

Abstract: An array substrate, a liquid crystal display and a control method thereof are disclosed. The array substrate includes scanning lines, data lines, pixel units, and common lines. Each common line is disposed along a row of pixel units. The array substrate also includes a common voltage supply line, and dual-channel selection switches each having an output terminal connected to a set of common lines, two input terminals connected to a common voltage high level supply line and a common voltage low level supply line respectively to selectively apply a high level or a low level to the common lines, thereby avoiding delay of the common voltage Vcom and the Vcom drift during a display mode and improving the display effect for an image.