Abstract: A method of preparing PAN-based carbon fibers relates to the technical field of materials. The method includes: S1. acrylonitrile, a second monomer and an unsaturated UV-sensitive cross-linking agent are mixed, an initiator is then added and a reaction is performed to obtain a meltable PAN-based copolymer; S2. the meltable PAN-based copolymer and a flow modifier are mixed to obtain a mixture, the mixture is extruded and pelletized, and then melt spinning is performed to obtain nascent fibers, the nascent fibers are stretched and annealed to obtain a PAN-based carbon fiber precursor; S3. ultraviolet irradiation is performed on the PAN-based carbon fiber precursor; S4. the PAN-based carbon fiber precursor after ultraviolet irradiation is pre-oxidized and carbonized to obtain PAN-based carbon fibers.

Abstract: A method for determining tobacco-specific nitrosamines (TSNAs) in cigarette smoke using one-step clean-up coupled with LC-MS/MS is provided, including the following steps: collecting a particulate matter of mainstream cigarette smoke with a Cambridge filter pad, mixing the particulate matter of mainstream cigarette smoke, an internal standards solution and water in a 50 mL plastic centrifuge tube, and vortexing the resulting mixture at room temperature to allow extraction; transferring an extraction solution after filtration to a new centrifuge tube, adding dichloromethane, and vortexing the resulting mixture; centrifuging to collect a dichloromethane extraction solution in a lower layer to another centrifuge tube, and placing the centrifuge tube in a water bath to remove dichloromethane; dissolving the resulting extraction solution in water, and transferring the resulting solution to an autosampler vial for LC-MS/MS analysis.

Abstract: A method for co-producing blister copper by enriching germanium and indium from a copper sulfide ore comprises: mixing a copper sulfide ore containing germanium and indium, a reducing agent and a fluxing agent in proportion and then grinding; subjecting the mixture to reduction matte smelting to obtain volatile smoke containing germanium and indium and copper matte respectively; subjecting the copper matte to oxygen-enriched blowing to volatilize germanium and indium, so as to obtain the blister copper and volatile smoke containing germanium and indium respectively; and oxidizing fumes discharged from bag dust collection by ozone, and then absorbing them by spraying alkali liquor to reach up-to-standard discharge. In the reduction smelting stage, the volatilization rate of germanium and indium is more than 70%; and in the copper matte oxygen-enriched blowing stage, the volatilization rate of germanium and indium is more than 25%.

Abstract: A method for determining tobacco-specific nitrosamines (TSNAs) in tobacco using one-step clean-up coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) is provided, including the following steps: destemming flue-cured tobacco or sun-cured tobacco, drying, milling, and passing through a sieve; mixing the resulting tobacco, an internal standards solution and water in a plastic centrifuge tube, and vortexing the resulting mixture at room temperature to allow extraction; transferring an extraction solution after filtration to a new centrifuge tube, adding dichloromethane, and vortexing the resulting mixture; centrifuging to collect a dichloromethane extraction solution in a lower layer to another centrifuge tube, and placing the centrifuge tube in a water bath to remove dichloromethane; dissolving the resulting extraction solution in water, and transferring the resulting solution to an autosampler vial for LC-MS/MS analysis.