Abstract: The invention provides a method for preparing pyrrolidone, and the invention provides a method for catalytically preparing pyrrolidone with ?-aminobutyric acid in the presence of carnitine-CoA ligase CaiC. The carnitine-CoA ligase CaiC has an amino acid sequence as shown in SEQ ID NO:1. The ligase has catalytic activity in the cyclization of ?-aminobutyric acid to produce pyrrolidone. The carnitine-CoA ligase provided in the present invention affords a yield of pyrrolidone of 3.26 g/L and a molar yield of 39.53% in 24 h when ?-aminobutyric acid is used as a substrate, thus reducing the production period, improving the production of pyrrolidone, and accelerating the industrialization process of producing pyrrolidone by enzymatic conversion method.

Abstract: A first network device generates a first clock. A second network device transmits a plurality of frames in response to receiving a request from the first network device. A third network device generates a second clock, receives the plurality of frames, generates time stamps based on the second clock, and transmits a first signal including the time stamps. The first network device receives the plurality of frames, receives the first signal, generates a second signal based on the plurality of frames and the first signal, and transmits the second signal. The third network device synchronizes the second clock of the third network device to the first clock of the first network device based on the second signal received from the first network device.

Abstract: A first network device including: a first clock module configured to generate a first clock signal; and a first clock control module configured to control the first clock signal to have a first frequency. The first clock control module includes a report reception and analysis module configured to: analyze a first signal, received from a second network device, to determine whether a second frequency of a second clock signal associated with the second network device requires adjustment in order to be synchronized with the first frequency of the first clock signal; and in response to the second frequency of the second clock signal requiring adjustment, generate a second signal to be transmitted via the antenna to the second network device, wherein the second signal is useable by the second network device to synchronize the second frequency of the second clock signal to the first frequency of the first clock signal.

Abstract: A clock control system for a reference network device, the clock control system including a reference clock module, a receiver module, and a clock adjustment module. The reference clock module generates reference clock signals. The receiver module receives and determines reference receive times of Y frames based on the reference clock signals. One of X remote network devices generates the Y frames. The receiver module further receives X-1 timestamp frames from X-1 of the X remote network devices based on receipt of the Y frames at respective ones of the X-1 remote network devices. X and Y are integers greater than or equal to 1. At least one of X and Y is greater than 1. The clock adjustment module determines and transmits clock adjustment signals for the X-1 remote network devices based on the X-1 timestamp frames and the reference receive times of the Y frames.