Abstract: The disclosure provides a method and apparatus for extracting an avalanche signal.

Abstract: A method and apparatus for measuring time, and a programmable controller for a quantum communication device are provided. The method includes: receiving a START signal and a STOP signal; sampling the START signal and the STOP signal by using a same clock to generate a START bit string corresponding to the START signal and a STOP bit string corresponding to the STOP signal; extracting a rising edge of the START signal from the START bit string, and extracting a rising edge of the STOP signal from the STOP bit string; and determining a time interval between the START signal and the STOP signal based on a count of bits between the rising edge of the START signal and the rising edge of the STOP signal and based on a period of the clock.

Abstract: The disclosure provides a method and apparatus for extracting an avalanche signal.

Abstract: Provided in the present disclosure are a gating apparatus for a single-photon detector, and a quantum communication device. The gating apparatus comprises: a system synchronization unit configured to acquire a clock of a quantum communication system; and a programmable controller configured to generate at least one periodic gating signal sequence that are synchronized with the clock of the quantum communication system, wherein gating signals in each gating signal sequence are spaced apart from each other by a predetermined duration, such that a single-photon detector can operate in a corresponding Geiger mode for a received optical pulse, and the predetermined duration is an optical path difference between a long arm and a short arm of an unequal-arm interferometer that is used for performing phase encoding in the quantum communication system.

Abstract: The disclosure provides a gating apparatus for a single-photon detector and a quantum communication device. The gating apparatus includes: a system synchronization unit, configured to obtain a periodic gating signal synchronized with a clock of a quantum communication system; a clock distributor, configured to divide the periodic gating signal into two periodic gating signals; a delay unit, configured to delay one periodic gating signal of the two periodic gating signals, so that the one periodic gating signal and the other periodic gating signal of the two periodic gating signals are spaced apart by predetermined duration; and a logical OR gate, configured to perform an OR operation on the one periodic gating signal delayed and the other periodic gating signal undelayed of the two periodic gating signals, so as to generate a periodic gating signal sequence synchronized with the clock of the quantum communication system.

Abstract: The present invention relates to use of a quaternary ammonium salt-type anthraquinone-based active material, and a salt cavern organic aqueous redox flow battery. The quaternary ammonium salt-type anthraquinone-based active material is used as a negative active material in a salt cavern battery, and a quaternary ammonium salt group is introduced, which can improve the solubility of anthraquinone in a neutral sodium chloride solution, thereby increasing the energy density of the battery. Also, the material has a relatively good stability, without the need for charging and discharging under the protection of an inert gas environment.

Abstract: The present invention relates to use of a quaternary ammonium salt-type anthraquinone-based active material, and a salt cavern organic aqueous redox flow battery. The quaternary ammonium salt-type anthraquinone-based active material is used as a negative active material in a salt cavern battery, and a quaternary ammonium salt group is introduced, which can improve the solubility of anthraquinone in a neutral sodium chloride solution, thereby increasing the energy density of the battery. Also, the material has a relatively good stability, without the need for charging and discharging under the protection of an inert gas environment.

Abstract: The present invention provides a method for synthesizing a carboxy-containing anthraquinone derivative, including the following steps: S1, mixing a terminal carboxy-containing dibasic acid with thionyl chloride, and adding toluene as a reaction solvent, followed by adding a catalyst and heating to a predetermined temperature for a reaction; S2, after the reaction is completed, removing the reaction solvent and the thionyl chloride, followed by adding toluene for distillation, to obtain a reactant; S3, mixing the reactant with aminoanthraquinone, adding toluene as a reaction solvent, followed by heating to reflux for a reaction; and S4, after the reaction is completed, removing the reaction solvent, adding a potassium carbonate solution to the residue, filtering it to remove a solid, adjusting the filtrate to a predetermined pH value to precipitate a solid, followed by filtering out, washing, and drying the precipitated solid, to obtain the carboxy-containing anthraquinone derivative.

Abstract: Disclosed is a method for preparing an organic environment-friendly snow-melting agent by using salt mud from a two-alkali method, relates to the field of environmental protection and resource utilization of solid wastes. The method includes the following steps: first, stirring and reacting an organic acid and the salt mud from a two-alkali method at room temperature to obtain a slurry; filtering the slurry to obtain a filtrate; the filtrate is then concentrated and dried by centrifugal spray drying to obtain a solid powder; granulating the solid powder. The method not only realizes the recycling of salt mud solid waste, but also greatly reduces the production cost of organic environment-friendly snow melting agent by turning waste into wealth, moreover, due to the existence of trace ions, the ability of melting snow and ice has obvious synergistic effect.

Abstract: Disclosed is a method for preparing an organic environment-friendly snow-melting agent by using salt mud from a two-alkali method, relates to the field of environmental protection and resource utilization of solid wastes. The method includes the following steps: first, stirring and reacting an organic acid and the salt mud from a two-alkali method at room temperature to obtain a slurry; filtering the slurry to obtain a filtrate; the filtrate is then concentrated and dried by centrifugal spray drying to obtain a solid powder; granulating the solid powder. The method not only realizes the recycling of salt mud solid waste, but also greatly reduces the production cost of organic environment-friendly snow melting agent by turning waste into wealth, moreover, due to the existence of trace ions, the ability of melting snow and ice has obvious synergistic effect.

Abstract: QKD systems having timing systems and timing method that allow for QKD to be performed in actual field conditions associated with practical commercial applications of quantum cryptography. The QKD system includes optical modems in each QKD station. Each modem has a circulator with an optical receiver and an optical transmitter coupled to it. One of the optical modems includes two phase lock loops and the other optical modem includes a phase lock loop and a transmit clock. Synchronization pulses are exchanged between the optical modems over a timing channel to synchronize the operation of the QKD system. The phase lock loops serve to lock a receive timing domain to a transmit time domain to ensure proper encoding and detection of weak quantum signals exchanged between the QKD stations.