Abstract: In the rapid urbanization process, the extensive development model of China's construction industry has led to excessive consumption of natural resources and intensified environmental. Its resource utilization has become an important topic for the sustainable development of the industry. This study proposes a composite admixture technology path to address the technical bottlene in the application of recycled micro-powder. By constructing a binary composite system of recycled concrete powder (RCP) and recycled brick powder (RBP), the characteristics and multi-age mechanical properties were systematically characterized and tested. The results show that compared with single RAP, the admixture of recycled micro-powder can significantly the mechanical properties of recycled mortar, among which the RCP: RBP = 8:2 group shows the best enhancement effect, with an increase in 2d compressive strength of 23.6% and an increase in flexural strength of 18.4%. The results show that the composite micro-pow system achieves a synergistic effect of micro-aggregate filling and volcanic ash activity through the gradient distribution of particle size, which effectively optimizes the microstructure of cement materials. The composite admixture technology framework established in this study not only improves the amount of recycled micro-powder admixture but also provides a new reference for the-value utilization of construction solid waste. Read More

Abstract: Solid propellants are critical in aerospace and military applications. HTPB solid propellants are widely used because of their excellent performance, but hot and humid environments have a significant impact on their performance. This paper reviews the research progress of HTPB solid propellant wet heat aging mechanism and aging performance test characterization method. With respect to the moisture-heat aging mechanism, chemical aging is manifested by polymer chain breakage and reorganization, and physical aging is manifested by the migration of plasticizers leading to microstructural instability; In the aging test characterization method, there are macro test and fine test. The current study suffers from homogenization of method application, little qualitative analysis, incomplete exploration of aging mechanisms and poor accuracy of life prediction models. In the future, new anti-aging additives should be developed and combined with artificial intelligence to optimize the aging prediction model. Read More

Abstract: In the present study, aminoated SBA-16@indoleacetic acid-@chitosan composite (NH2-SBA-16@IAA@CS) was prepared on glass plate (supporting substrate). Indoleacetic acid (IAA) was introduced into aminoized SBA-16 (NH2-SBA-16), mixed with chitosan and coated on glass plate to form antibacterial slow-release coating. BET, XRD and FTIR results showed that IAA was successfully introduced into the aminating SBA-16 material. The antibacterial activity of the composite coating was studied using the biofilm-forming bacteria Bacillus subtilis and Escherichia coli. Under the same conditions, NH2-SBA-16@IAA@CS composite coated fiberglass board showed antibacterial activity compared with chitosan. The release time and amount of IAA in the composite material were also tested, and it was found that the release rate of IAA in the prepared composite coating was effectively reduced in the alkaline seawater. NH2-SBA-16@IAA@CS composites are promising alternatives to toxic antifouling coatings in the ocean. Read More

Abstract: Polyamide 6 (PA6) is an important semi-crystalline engineering plastic widely used in electrical appliances, automotive materials, and other applications. However, PA6 is highly susceptible to moisture absorption, which can significantly alter its physicochemical properties. In this study, PA6 was synthesized via anionic ring-opening polymerization, and immersion tests were conducted in accordance with ISO 175:2010. The influence of environmental factors on the non-isothermal crystallization behavior of PA6 was investigated. The Mo equation was successfully employed to characterize the entire non-isothermal crystallization process. The obtained kinetic parameters provide valuable insights for predicting the performance of PA6 under practical conditions and serve as a reference for the modification and optimization of PA6. Read More

Abstract: To solve the problems of high labor intensity, and difficulty in controlling the quality of traditional filling materials filling systems, a one-component lane-side filling material with better load-bearing performance has been developed with corresponding filling equipment and process. In order to grasp the engineering performance of the filling material, orthogonal experimental method was adopted to test the basic performance of the bearing layer material, and the influence of various factors such as water-cement ratio and additives on the initial and final solidification time, reaction temperature and compressive strength of the slurry was investigated through the method of analysis of extreme difference. The results show that: the water-cement ratio has a greater impact on the four performance indicators; the mixing of appropriate amount of quick-setting agent can accelerate the slurry setting rate and reaction temperature; the mixing of early-strength agent and fibre can improve the early compressive strength and toughness of the specimen; comprehensive analysis of the third group of specimens under the load-bearing layer materials with quick-setting, early-strength characteristics, setting time of 9 minutes or less, the maximum compressive strength of 23.3MPa. At the same time, after the simulation test of the specimen with different support schemes, it was found that the integrity and stability of the filling body was improved under the joint restraint of tensile reinforcement, steel ladder beams and reinforcing mesh in the specimen of group D-4. The final on-site monitoring results show that: the displacement of the roadway surface increases after the roof collapses, in which the maximum amount of roof subsidence is 139mm, and the maximum amount of the two gangs approaching is 40mm, and the hollow area tends to be stable under the support of the filling body after compaction, which will ensure the safety of the next working face when it is being mined back. Read More

Abstract: In this study, a higher quality MA0.9FA0.1PbI2.85Br0.15 film was surface treated with phenylethylamine iodide (PEAI), and a perovskite solar cell (PSC) with high stability and high efficiency carbon pair electrode was prepared. The I- and PEA+ ions in PEAI fill the defects between the perovskite crystals, passivate the surface, improve the quality of the film, increase the size of the perovskite grains, reduce the carrier recombination, and enhance the optical properties. By comparing and testing the effect of a series of different PEAI solution concentrations on the quality of MA0.9FA0.1PbI2.85Br0.15 film, the optimal concentration of PEAI solution is 1.5mg /mL, and the optimal PCE of the device is 11.25%. PSCs were higher than those of untreated MA0.9FA0.1PbI2.85Br0.15 films. The unpackaged and PEAI solution surface treated battery devices are more stable in an air atmosphere, and the PCE of the device after 60 days remains at 96% of the initial PCE. Read More

Abstract: The Rotational Friction Extrusion (RFE) technique was successfully employed to fabricate graphite particle-reinforced AZ31 magnesium matrix composites (Gr/AZ31Mg). The microstructure, hardness, and wear properties of the composites were systematically analyzed. The results indicate that the RFE process enables the production of rod-shaped Gr/AZ31Mg composites with well-defined dimensions and high forming quality. The microstructure of the composites consists of fine equiaxed grains formed through dynamic recrystallization, with uniformly distributed Gr particles within the magnesium matrix, contributing to enhanced overall performance. Hardness measurements reveal that the addition of Gr significantly influences the hardness of the composites, exhibiting an initial increase followed by a slight decline. When the Gr content reaches 1.5 wt.%, the composite's hardness is improved by 20.2% compared to the unreinforced AZ31Mg matrix. Regarding wear performance, Gr particles act as solid lubricants during the friction process, reducing direct contact wear, thereby decreasing wear volume and enhancing wear resistance. The variation trends of the friction coefficient and wear rate align with those of hardness; both parameters initially decrease with increasing Gr content and then exhibit a slight rebound. At a Gr content of 1.5 wt.%, the composite achieves the lowest wear rate of 0.197, representing a 33.7% reduction compared to the RFE-processed AZ31Mg matrix, indicating optimal wear resistance at this reinforcement level. Read More

Abstract: All-inorganic perovskite CsPbX3 (X=Cl, Br, I) nanocrystals have attracted extensive attention due to their excellent photoelectric properties. These materials not only have the advantages of tunable emission wavelength, emission peak width and high fluorescence quantum yield, but also are significantly superior to traditional organic-inorganic hybrid systems in terms of device compatibility and environmental stability. They have shown great application potential in the field of optoelectronic devices and have been successfully applied to the construction of functional modules such as light-emitting layer (LEDs), photovoltaic light-absorbing layers and laser gain medium. In recent years, it has become a research hotspot to regulate the physical and chemical properties of CsPbX3 nanocrystals through ion doping engineering. The doping strategy can effectively adjust the band structure and luminescence properties of the material, and its mechanism is mainly due to the perturbation of the crystal field and the modification of the defect state by the doping elements. In this paper, the international research trends of X-site doping of this material are systematically reviewed. The crystal structure characteristics, optical performance regulation mechanism and mainstream preparation technology are described. The optimization mechanism of halogen site chemical modification on the photoelectric properties of materials is analyzed. Finally, the current technical bottleneck and future development direction are discussed. Read More