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According to the requirements of Al foil surface modification, the surface of Al foil is baked, corona and coated with carbon, and 6 Ah pouch type lithium iron batteries is made. The effects of surface modification methods on the performance of Al foil, electrode plate and battery are evaluated through the tests of Al foil surface roughness, electrode plate rolling adhesion, electrochemical impedance, storage, cycle, etc. The results show that the surface roughness of Al foil is increased by 41% after corona, and the adhesion of the electrode sheet is thus increased by 3.166 times as much as that of the base foil. After corona and carbon coating treatment, the impedance of the battery is reduced by one capacitance arc between the aluminum foil and the active substance. The alter-nating current resistance(ACR) of the battery is reduced to 5.59 mΩ, and the consistency of the internal resistance of the battery is improved. Corona and carbon coating can improve the high current discharge performance of the battery, reduce polarization, and improve the discharge platform, but carbon coating is more significant than corona. At the same time, the coated carbon significantly improves the high temperature cycle. [ABSTRACT FROM AUTHOR]

With the hasten development of the new energy industry, the recycle of power and energy storage lithium-ion batteries began to be gradually valued. In order to ensure the cleanliness and environmental protection of the whole life cycle of lithium-ion batteries, the feasibility of recycling the positive and negative core materials in lithium-ion batteries needs to be further evaluated, so as to achieve the closed loop of the new energy industry chain with lithium-ion batteries as the core. The properties of a recycled LiFePO4 cathode material are verified, and the effect of changes in physical and chemical indexes of the material on the processing performance and the impact of the electrical performance after processing into a battery are evaluated. The results show that the main physical properties of recycled LiFePO4 obtained by physical drying method can meet the requirements of battery manufacturing grade. ICP test results show that the Al content is high, magnetic impurities, gram capacity and recovery powder particle size distribution and other physical and chemical indicators are not significantly abnormal, but there is still a large room for improvement, by following the process processing performance of the recovery of LiFePO4, the direct current resistance of the pole is fluctuates. The results of charge storage at room temperature test show that the capacity retention rate of the cell after 28 days has reached more than 92%, recovery rate more than 93%, which meets the requirements of the national standard, indicating that the necessary demagnetization operation to increase the powder and slurry plays a certain role in reducing the risk of self-discharge of the final finished battery. The cell cycle test results show that the capacity retention rate of 0.2 C for 100 cycles is more than 95%, which is comparable to the normal LiFePO4 processing of the cell cycle performance level. [ABSTRACT FROM AUTHOR]

In the present study, we propose a novel method for the extraction of parabens in personal care products. A new, simple adsorptive material was obtained by combining metal‐organic frameworks and melamine sponges using the adhesive property of polyvinylidene fluoride. This new material, metal‐organic frameworks/melamine sponges, was found to be particularly suitable for solid‐phase extraction. The structural characteristics of metal‐organic frameworks/melamine sponges were first analyzed by scanning electron microscopy. Subsequently, solid‐phase extraction was performed on sample solutions, and the extracted substances were then analyzed by high‐performance liquid chromatography. Following optimization of important experimental conditions, excellent recovery rates were obtained. Our novel method was then applied to the extraction of four parabens (methylparahydroxybenzoates, ethylparahydroxybenzoates, propylparahydroxybenzoates, and butylparahydroxybenzoates) from real samples. The results yielded limits of detection of 0.26–0.41 ng/mL. The inter‐ and intra‐day recoveries were 104.0–109.7% and 91.2–98.1%, respectively (relative standard deviation, <13.8%). [ABSTRACT FROM AUTHOR]

Much effort has been devoted to the metabolic engineering of Klebsiella pneumoniae; however, our knowledge of the actual expression level of promoters used in K. pneumoniae is limited. In this study, the expression levels of three promoters were compared systematically by using the lacZ reporter gene with different carbon sources in K. pneumoniae. The results showed that, although promoters P T5 and P tac designed for Escherichia coli were functional, P T5 appeared more efficient and the induction/repression ratio of P tac was decreased extremely in K. pneumoniae. The basal level of P tac for lacZ expression reached 396.5 U/mg, which was 9.5-fold higher compared with P T5 in LB medium, indicating P tac can be used as an efficient 'constitutive' promoter as well as an efficient induced promoter in K. pneumoniae. In different carbon sources medium, a newly constructed endogenous constitutive P bud proved to be a stable and weak promoter. On the basis of our data, a set of P bud and P tac promoters could meet the broad range (about 1,000 orders of magnitude) of gene expression needed for engineered K. pneumoniae in glycerol-based medium. [ABSTRACT FROM AUTHOR]