Abstract: A process for producing high-purity ?-caprolactam includes the following steps: (1) cyclohexanone oxime is subjected to a gas phase Beckmann rearrangement reaction; (2) the reaction product obtained from step (1) is successively subjected to gas-liquid separation, solvent removal, and light impurity removal to produce a crude caprolactam; (3) the crude caprolactam is subjected to crystallization to produce a crystallization product and a crystallization mother liquor; (4) the crystallization mother liquor is subjected to crystallization to produce a crystal slurry. At least a part of the crystal slurry is returned to step (2) and/or step (3). The purification process can obtain high-purity caprolactam through only one crystallization and one mother liquor crystallization without reducing the overall yield of caprolactam.

Abstract: The present invention discloses an optical line transmission protection system and method. In which, the optical line transmission protection system includes: at least one stage of optical line protection segment having a transmitting end provided with a Tunable Optical Divide Module (TOD), and a receiving end provided with an OSW; the transmitting end of a local Optical Line Protector (OLP) is connected to the receiving end of an opposite OLP to form main and standby optical lines; and the TOD is configured to set splitting ratios of the main and standby optical lines according to a difference between the optical fiber states of the current working channel and non-working channel, and tune optical power distributions at respective transmitting ends of the main and standby optical lines, according to the splitting ratios of the main and standby optical lines.

Abstract: The present invention discloses an optical line transmission protection system and method. In which, the optical line transmission protection system includes: at least one stage of optical line protection segment having a transmitting end provided with a Tunable Optical Divide Module (TOD), and a receiving end provided with an OSW; the transmitting end of a local Optical Line Protector (OLP) is connected to the receiving end of an opposite OLP to form main and standby optical lines; and the TOD is configured to set splitting ratios of the main and standby optical lines according to a difference between the optical fiber states of the current working channel and non-working channel, and tune optical power distributions at respective transmitting ends of the main and standby optical lines, according to the splitting ratios of the main and standby optical lines.