Search Results (2)

In order to respond to the greenhouse effect and achieve sustainable development, microbial-induced carbonate precipitation (MICP) technology based on the spraying method was used as a substitute for Portland cement to reinforce calcareous sand. In order to simulate the tide and determine the suitable concentration, the effects of the initial water level and cementing solution (CS) concentration on the reinforcement were analyzed. The results showed that the distributions of penetration resistance and equivalent calcium carbonate content mainly include two patterns: monotonically decreasing, and initially increasing and then decreasing. The fully saturated case only showed a dense, thin layer of calcium carbonate on the surface, and in the completely dry case, middle cementation was produced. When the initial water level was 0.5 m, the largest range of 60 cm of effective cementation appeared, and both the equivalent calcium carbonate content and penetration resistance were the highest because the microorganisms were more likely to migrate to the particle connection. The calcium carbonate generated by the MICP reaction played a role in increasing the water retention capacity of the sand. As the degree of cementation increased, the SWRC gradually moved up and the matrix suction corresponding to the same volume water content increased sequentially. Increasing the spraying times and the concentration of CS generated more calcium carbonate. The penetration resistance of higher CS concentrations was larger with the same calcium carbonate content. There was a linear relationship between the normalized penetration resistance and the normalized shear wave velocity. Full article

Binary nanoparticle inks comprising Ag₂Se, In₂Se₃, and Ga₂Se₃ were fabricated via a wet ball-milling method and were further used to fabricate AgInGaSe₂ (AIGS) precursors by sequentially spraying the inks onto a Mo-coated substrate. AIGS precursors were annealed under a Se atmosphere for 1 h at 570 °C. Na₂Se thin layers of varying thicknesses (0, 5, 10, and 20 nm) were vacuum-evaporated onto the Mo layer prior to the AIGS precursors being fabricated to investigate the influence on AIGS solar cells. Sodium plays a critical role in improving the material properties and performance of AIGS thin-film solar cells. The grain size of the AIGS films was significantly improved by sodium doping. Secondary ion mass spectroscopy illustrated slight surficial sodium segregation and heavy sodium segregation at the AIGS/Mo interface. Double-graded band profiles were observed in the AIGS films. With the increase in Na₂Se thickness, the basic photovoltaic characteristics of the AIGS solar cells were significantly improved. The highest solar cell conversion efficiency of 6.6% (open-circuit voltage: 775.6 mV, short-circuit current: 15.5 mA/cm², fill factor: 54.9%, area: 0.2 cm²) was obtained when the Na₂Se thickness was 20 nm. Full article