| 1. |
- Jin, Yunzhe, et al.
(författare)
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Experimental and numerical simulation study on the evolution of mechanical properties of granite after thermal treatment
- 2024
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Ingår i: Computers and geotechnics. - : Elsevier BV. - 0266-352X .- 1873-7633. ; 172
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Tidskriftsartikel (refereegranskat)abstract
- High temperature significantly influences the mechanical properties of granite, which is relevant to various engineering applications, including geothermal energy extraction. The objective of this study is to investigate the meso-mechanics of granite, specifically focusing on the formation of thermal cracks and the temperature-dependent mechanical properties in heterogeneous rock. Firstly, we heat the granite to 25–1000 ℃ by muffle furnace. Following this, we conduct triaxial compression tests with 0–20 MPa confining pressures on the heated-specimens cooled by cold water. Subsequently, we combine the grain-based model (GBM) and the finite-discrete element method (FDEM) to simulate the heat treatment process and the triaxial experiments. We calibrate the micromechanical parameters of granite by experimental results. Results show that the mechanism behind the formation of thermal cracks in granite subjected to high-temperature is the differential thermal expansion coefficients of mineral particles in granites, leading to the degradation of mechanical properties in thermal-treated granite. The temperature threshold for the formation of thermal cracks is between 500 °C and 550 °C. Particularly, the stress-strain curve of granite exhibits ideal elastic-plastic characteristics under temperature is 1000 °C. These results can help to demonstrate the temperature-dependent evolution of mechanical properties of crystalline rocks, providing a theoretical basis for the utilization of engineering applications.
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| 2. |
- Wang, Yilin, et al.
(författare)
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Control of the Crystallization and Phase Separation Kinetics in Sequential Blade-Coated Organic Solar Cells by Optimizing the Upper Layer Processing Solvent
- 2023
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Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6832 .- 1614-6840. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- Sequential deposition of the active layer in organic solar cells (OSCs) is favorable to circumvent the existing drawbacks associated with controlling the microstructure in bulk-heterojunction (BHJ) device fabrication. However, how the processing solvents impact on the morphology during sequential deposition processes is still poorly understood. Herein, high-efficiency OSCs are fabricated by a sequential blade coating (SBC) through optimization of the morphology evolution process induced by processing solvents. It is demonstrated that the device performance is highly dependent on the processing solvent of the upper layer. In situ morphology characterizations reveal that an obvious liquid–solid phase separation can be identified during the chlorobenzene processing of the D18 layer, corresponding to larger phase separation. During chloroform (CF) processing of the D18 layer, a proper aggregation rate of Y6 and favorable intermixing of lower and upper layers results in the enhanced crystallinity of the acceptor. This facilitates efficient exciton dissociation and charge transport with an inhibited charge recombination in the D18/CF-based devices, contributing to a superior performance of 17.23%. These results highlight the importance of the processing solvent for the upper layer in the SBC strategy and suggest the great potential of achieving optimized morphology and high-efficiency OSCs using the SBC strategy.
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