To realize fast synthesis of cadmium sulfide (CdS) quantum dots with a low-toxic material, a one-step synthesis method is investigated and conducted. Potato extract is used as a stabilizer and modifier, by which aqueous CdS quantum dots can be prepared at a lower temperature with a shorter time. Through systematic characterization and analysis, a green and fast synthesis mechanism is demonstrated in detail. And the nanoscale CdS quantum dots are uniform in size and dispersity. With low cost and high sensitivity, the prepared CdS quantum dots show promising application in silver-ion detection. This method shows great significance for an environmentally friendly and facile synthesis of CdS quantum dots.

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In this study, a novel method was adopted to construct a CdS−TiO 2 heterostructure to degrade penicillin under sunlight. A potato extract was used during the synthesis process of CdS QDs as a stabilizer and a modifier. The CdS−TiO 2 composite with a heterostructure delivers high photocatalytic degradation efficiency. In detail, 0.6 mg/mL of CdS−TiO 2 can successfully decompose penicillin after 2 h, and 5‰ CdS−TiO 2 shows the optimal degradation efficiency with the degradation rate reaching 88%. Furthermore, the underlying mechanisms of the penicillin decomposition reaction were investigated by the EPR test and trapping experiment. It was found that the high photocatalytic degradation efficiency was attributed to the heterojunction of CdS−TiO 2 , which successfully suppresses the recombination of the conduction band of CdS and the valence band of TiO 2 . Moreover, it was confirmed that the reaction is the O 2 -consuming process, and introducing O 2 can greatly accelerate the generation of a superoxide radical during the photocatalytic degradation process, which eventually improves the degradation of penicillin and shortens the degradation time. Finally, this work provides the possible penicillin degradation pathways, which will inspire the researchers to explore and design novel photocatalysts in the field of wastewater treatment in the future.

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In northeastern China, successive years of cultivation have led to a decline in soil quality, a process that is exacerbated by the over-application of chemical fertilizers to ensure staple food production. The large amount of straw produced by cultivation is difficult to effectively use in recent years. There has been an increasing amount of research on the transforming straw into biomass char, but it has often focused on the effects of biomass char addition on soil physicochemical properties, without further exploring the mechanisms of this process and its effects on soil microorganisms. Microorganisms are an important part of the soil system and the process of how biomass char addition affects microorganisms through its effect on soil physicochemical properties should not be overlooked. In this study， the effect of biochar application at different preparation temperatures (300°C, 400°C and 500°C) and addition contents (0.1% and 1%) on ammonia, nitrate and total nitrogen in soil leachates were investigated. The effect of microbial sequencing on the dynamics of carbon and nitrogen was also investigated to reveal the mechanisms contributing to the changes in nitrogen forms. The results showed that biochar had a better adsorption ability on ammonia nitrogen, and biochar promoted the conversion of ammonia nitrogen to nitrate nitrogen by nitrifying bacteria. The addition of 1% biochar (prepared at 500°C) increased nitrate-nitrogen leaching by 86.52% compared to the control treatment. The sequencing of microorganisms also revealed that biochar changed the structure and abundance of the soil microbial community, especially increasing the relative abundance of the Helicobacter nitrification phylum by 2.02%. These results indicates that biochar facilitated the adsorption of ammonium nitrogen and the conversion of nitrate nitrogen, and solving the problem of low nitrogen fertilizer utilization while promoting the formation of beneficial bacteria in the soil.

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Wind loads on structures are difficult to directly measure, so it is practical to identify structural wind loads based on the measurements of structural responses. However, this inversed problem is challenging compared with conventional load identification as wind loads are time-space coupled and spatially distributed dynamic loads on structures. An improved method is proposed for identifying wind loads on structures using only partial measurements of structural acceleration responses in this paper. First, the wind loads on a structure are decomposed by proper orthogonal decomposition as a series of time-space decoupled sub-distributed dynamic loads with independent basic spatial distribution functions and time history functions. Herein, structural modes are adopted as the basic spatial distribution functions and structural modes of discretized and continuous structural systems are investigated. Then, a history function of the decomposed wind load is identified in the modal domain based on modal Kalman filter with unknown inputs, which is proposed by the authors. Finally, the distributed wind loads are reconstructed for discrete or continuous structural systems. The feasibility of the proposed algorithm is verified by two numerical examples of identification of wind loads on a discrete shear frame and a wind turbine tower, respectively.