Abstract: This invention relates to methods of preparing and purifying .alpha.-substituted acetic acids, which comprise treating an .alpha.aromatic-substituted acetic acid represented by a specific general formula with a weak alkali while shielding light, or subjecting an .alpha.-aromatic-substituted acetonitrile represented by a specific general formula to acid hydrolysis, followed by treatment with a weak alkali while shielding light; and treating the alkali salt of .alpha.-substituted acetic acid thus formed with a decolorizing agent.

Abstract: A graphic display system using a cathode ray tube is disclosed, which display M line segments where M is based on an integer greater than 1 selected exclusively from integers not based on powers of 2 for each raster scanning line (line scan) in response to video data from a bit mapped refresh memory. The refresh memory is divided into memory blocks which are assigned sequential addresses and each store video dot data for one line segment. The memory is organized with N memory blocks for each scanning line, where N is an integer greater than M based on an integer selected from integers generated by powers of 2. The memory blocks are addressed with M blocks addressed during the display time and (N-M) blocks addressed during the remaining time of each line scan during which the CRT is blanked. The memory addressing rate is increased to complete the addressing of (N-M) blocks during the blanking time.