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The ocean covers 70% of the earth’s area, and the seawater uranium is more than 1000 times that of terrestrial uranium ore. In order to increase the power generation and ensure the sustainable operation of nuclear power plants, the development of unconventional uranium resources is of great significance. As an effective means to solve shortage of terrestrial uranium resources, uranium extraction from seawater has received extensive attention in recent years. At present, many methods including membrane separation, chemical deposition, solvent extraction, ion exchange, reduction and adsorption have been applied to uranium extraction from seawater. This paper focuses on the recent research progress of adsorption method used inorganic materials, organic materials, carbon materials as adsorbent, and emerging electroreduction technologies, and further discusses the challenges and opportunities of these two methods.

How to solve the contradiction between coal mining and soil and water conservation is the key scientific problem to realize the ecological environment protection and high-quality development in the middle reaches of the Yellow River. In this paper, taking the coal mining subsidence area in loess gully of northern Shaanxi as the research object, aiming at the typical geological occurrence characteristics of the main coal seam, and taking the underground mining thickness (9, 7, 5 m), the natural slope shape (straight slope, concave slope, convex slope, compound slope) and slope (5°, 15°, 25°, 35°, 45°) of the surface loess as variables, a total of 60 numerical models are constructed. In this paper, based on FLAC3D numerical simulation software, the evolution process and law of slope morphology under the coupling effect of loess natural slope morphology and mining thickness are studied. Then, based on China soil erosion equation (CSLE model) and empirical model, the soil erosion effect of subsidence slope is calculated and analyzed. The results show that: ① Coal mining subsidence will lead to the increase of the slope of the surface loess slope, and the greater the mining thickness, the greater the slope increase. Significant Amplification Effect of Large Mining Thickness on Slope Gradient Increase of Surface Loess Caused by Coal Mining Subsidence. The concave slope generally has a significant effect on the slope of the subsidence slope, especially under the conditions of “ mining thickness 5 m, natural slope > 5 ° ”, “mining thickness 7 m, arbitrary natural slope ”, “ mining thickness 9 m, natural slope ≤ 35°”. No matter what kind of mining thickness and natural slope shape, the natural slope of ≤ 5 ° has the greatest influence on the increase of subsidence slope. ② Coal mining subsidence will lead to the increase of M1 on the surface loess slope under the scale of “ annual erosion rainfall ”, and the greater the mining thickness, the greater the increase of M1. When the mining thickness increases from 5 m to 9 m, M1 increases by about 1 time. The concave slope of four slope shapes has the greatest influence on the increase of M1 on the subsidence slope. The natural slope of ≤ 15° has a great influence on the increase of M1, which is more than 20% under the condition of “ mining thickness 9 m, concave slope ”. ③ Coal mining subsidence will lead to the increase of M2 of surface loess slope under the scale of “ typical erosion rainfall ”, and the greater the mining thickness, the greater the increase of M2 ; when the mining thickness increases from 5 m to 9 m, the increase of M2 increases by about 1 times. The concave slope of the four slope shapes has the greatest influence on the increase of M2 on the subsidence slope. The natural slope of ≤ 15° has a great influence on the increase of M2, which is more than 17 % under the condition of “ mining thickness 9 m, concave slope ”. The results can provide scientific basis for accurate prevention and control of soil erosion and high-quality development in the mining area of northern Shaanxi and even the middle reaches of the Yellow River Basin.

Friction stir lap welding (FSLW) of dissimilar acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) was conducted using a double-pin tool. The formation process of the weld and the influences of rotational speed on the microstructure and mechanical property were investigated. It was found that the weld was generated accompanying with the closure of old cavities in the front of the pins and the simultaneous regeneration of new cavities in the rear of the pins. Annular material flow on the vertical and horizontal directions occurred during FSLW. With the increase of the rotational speed, the PC anchors resulted from the upflow of plasticized PC layer and the shoulder affected zone both enlarged. Microstructure analysis of the weld nugget showed that PC was fragmented into lamellar, columnar, and spherical particles and their dimensions decreased when rotational speed increased. Lap-shear tensile tests showed that the weld strength increased with higher rotational speed and the maximum strength of the weld produced under 800 r/min reached 19.38 MPa, which was comparable to the ABS/PC welds produced by a tapered pin under the optimal parameters. Through the further optimization of such FSLW process, it was potential to join dissimilar polymeric components in future industrial manufacturing field. [ABSTRACT FROM AUTHOR]

Aramid is widely recognized for its effectiveness as a matrix in high-performance composite materials. However, the inert nature of its surface necessitates plasma pretreatment for proper resin immersion. With a particular focus on interactions involving O radicals, this study employs Vacuum Ultra-Violet Photolysis Reactive-species Supply to investigate the interaction mechanisms between aramid and plasma reactive species. The water contact angle serves as an indicator of the degree of surface reactions, demonstrating a clear correlation between its reduction and the concentration of O radicals. Analysis using ATR-FTIR and XPS revealed the depletion of amide groups and the formation of hydroxyl groups during the treatment process. Through reactive molecular dynamics simulations, we identified the specific reaction sites of the amide groups on aramid and quantified the variations in typical reaction products. We also summarized the reaction pathways and confirmed the generation of polar structures, such as N-OH. This study offers valuable theoretical insights for the surface modification of inert polymers and contributes to advancements in industrial plasma technology. [ABSTRACT FROM AUTHOR]

Described herein is a dirhodium(II)‐catalyzed silylation of propargyl esters with hydrosilanes, using tertiary amines as axial ligands. By adopting this strategy, a range of versatile and useful allenylsilanes can be achieved with good yields. This reaction not only represents a SN2′‐type silylation of the propargyl derivatives bearing a terminal alkyne moiety to synthesize allenylsilanes from simple hydrosilanes, but also represents a new application of dirhodium(II) complexes in catalytic transformation of carbon‐carbon triple bond. The highly functionalized allenylsilanes that are produced can be transformed into a series of synthetically useful organic molecules. In this reaction, an intriguing ON‐OFF effect of the amine ligand was observed. The reaction almost did not occur (OFF) without addition of Lewis base amine ligand. However, the reaction took place smoothly (ON) after addition of only catalytic amount of amine ligand. Detailed mechanistic studies and density functional theory (DFT) calculations indicate that the reactivity can be delicately improved by the use of tertiary amine. The fine‐tuning effect of the tertiary amine is crucial in the formation of the Rh−Si species via a concerted metalation deprotonation (CMD) mechanism and facilitating β‐oxygen elimination. [ABSTRACT FROM AUTHOR]