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The coffee-growing areas in the Gaoligong Mountains of China face ecological challenges including soil erosion and water pollution from traditional processing methods. To analyze the drivers of stakeholder participation in addressing these issues, this study integrates the Theory of Planned Behavior (TPB) and Social Network Embeddedness Theory (SNET), which together explain how individual cognitions and social structures shape cooperative behavior. Data from a stratified survey of 137 stakeholders were analyzed using PLS-SEM. The results demonstrate that (1) Both emotional networks (ENW) and suggestive networks (SNW) have significant direct effects on participation intention. (2) Indirectly, ENW enhances intention by strengthening individual behavioral attitude, subjective norm, and perceived behavioral control through emotional bonds and identity. (3) SNW improves intention primarily by boosting perceived behavioral control through information dissemination. And (4) the core TPB constructs (attitude, norm, control) are confirmed as key mediators. This paper contributes a validated integrated framework that elucidates the social-psychological pathways for fostering effective ecological co-management.

This paper presents a kernel extreme learning machine (KELM) integrated with the improved whale optimization algorithm (IWOA) to address the power quality disturbance (PQD) issue in microgrids. First, an adaptive variational mode decomposition method is employed to extract PQD signals in microgrids. Then, the IWOA is utilized to optimize the penalty factor and kernel function parameters for the KELM classifier model, thereby enhancing the performance of the classifier. Furthermore, the test results indicate that the proposed IWOA–KELM achieves high classification accuracy and rapid convergence for complex PQD signals. This paper presents a kernel extreme learning machine integrated with the improved whale optimization algorithm to address power quality issues in microgrids resulting from distributed power access. In this work, the adaptive variational mode decomposition method is employed to decompose the complex disturbance signals in microgrids.

Deep-blue perovskite light-emitting diodes (PeLEDs) based on reduced-dimensional perovskites (RDPs) still face a few challenges including severe trap-assisted nonradiative recombination, sluggish exciton transfer, and undesirable bathochromic shift of the electroluminescence spectra, impeding the realization of high-performance PeLEDs. Herein, an in situ chlorination (isCl) post-treatment strategy was employed to regulate phase reconstruction and renovate multiple defects of RDPs, leading to superior carrier cooling of 0.88 ps, extraordinary exciton binding energy of 122.53 meV, and higher photoluminescence quantum yield of 60.9% for RDP films with deep-blue emission at 450 nm. The phase regulation is accomplished via fluorine-derived hydrogen bonds that suppress the formation of small- n phases. Multiple defects, including halide vacancies (shallow-state defects) and lead-chloride antisite defects (deep-state defects), are renovated via C=O coordination and hydroxy-group-derived hydrogen bonds. Consequently, deep-blue PeLEDs with a record maximum external quantum efficiency of 6.17% and stable electroluminescence at 454 nm were demonstrated, representing the best-performing deep-blue PeLEDs. In situ chlorination strategy was proposed to renovate multiple defects along with reconstruction of phases in RDPs for efficient and spectrally stable deep-blue PeLEDs with a record EQE of 6.17%.

Visible light communication (VLC) aided by unmanned aerial vehicles (UAVs) offers significant advantages in adapting to dynamic network requirements, but the endurance and service capability of UAVs are still the key limiting factors. To overcome this limitation, the UAV array-aided VLC system with an enhanced angle diversity transmitter (ADT) is proposed to improve energy efficiency (EE). Enhanced ADTs with varying LED layers, multiple LEDs per layer, and inter-layer rotation angles are considered. By jointly optimizing the inclination angle of the side LEDs in the enhanced ADT and the hovering height of the UAVs, this research aims to minimize the power consumption of the UAV array-aided VLC system while meeting illumination and communication requirements. The simulation results present that the EE of the centralized single-UAV VLC system can be greatly improved by applying the enhanced ADT structures. More specifically, compared with the single LED transmitter configuration, an EE enhancement of up to 215.7% can be achieved by the enhanced ADT, which employs multi-layer LEDs, inter-layer rotation, and layer-doubled designs. In addition, the EE can be further improved by the deployment of a distributed UAV array. The VLC system with four UAVs is demonstrated to achieve a peak EE performance of 19.9 bits/J/Hz, representing a 298% improvement over the centralized single-UAV configuration.

To understand the effects of thermal shock on microcrack propagation and permeability in coal, thermal shock tests were conducted on coal specimens by using a constant temperature drying oven (105 °C) and a SLX program controlled cryogenic tank. The growth and propagation of microcracks were measured with computer tomography (CT) scanning and scanning electron microscope (SEM) tests. Results showed that thermal shocks improved the permeability of coal significantly. Notably, the permeability of coal after thermal shocks increased from 211.31% to 368.99% and was positively correlated with temperature difference. CT scanning images revealed that thermal shocks increased the crack number, crack volume and crack width as well as smoothened and widened the gas flow paths, thereby enhancing coal permeability. Moreover, SEM images showed that heating-cooling shocks created more new microcracks, forming more complex crack propagation paths and better connectivity among microcracks in coal compared to cooling shocks. We proposed a crack propagation criterion for coal to explain the mechanism of crack failure and propagation during thermal shocks. Our experiment results and theoretical analysis indicate that the heating-cooling shock is more effective in damaging and breaking coal than the cooling shock. Thus, it can be used as an alternative approach to enhance coal permeability in the production of coalbed methane (CBM).

To address the problems of insufficient precision reserve, limited rotational speed, and excessive temperature rise in high-speed ultra-precision machine tool spindle bearings, the influence of frictional power loss on the thermo-mechanical behavior of the bearing system was investigated. Firstly, based on the analysis of the heat source of the bearing, the friction power consumption model of the bearing assembly is established, and the analysis of the bearing temperature field is realized by studying the heat energy transfer. Secondly, the test bench is built for experimental verification. Finally, through the study of thermal-mechanical coupling performance, the influence of different rotational speeds on bearing stress and life is analyzed. The results show that the friction power consumption generated by the spin sliding of the bearing rolling element accounts for the largest proportion, accounting for 31% of the total friction power consumption; the increase in bearing speed will increase the bearing temperature. At 55,000 r/min, the highest temperature at the rolling element is close to 75 °C, followed by the inner ring up to 68 °C, and the lowest outer ring temperature is 57 °C. The temperature has a great influence on the bearing performance. Under the same working conditions, the equivalent stress is increased by 21%, the contact pressure is increased by 25%, and the fatigue life of the bearing is reduced by 5.6%. Bearing performance is significantly affected by thermodynamic behavior.

Gas extraction from coal seams in China faces various middle-term and long-term problems, such as the poor sealing quality and low extraction rate. The mean gas extraction concentration is only 30%. Studying the flowing laws of the grout and fracture plugging mechanism is of important significance to improve the sealing quality and increase the gas extraction efficiency. For this reason, a new coal-based grouting material was prepared in this study, and its parameters such as viscosity were tested. Moreover, a grouting theoretical model with considerations of the flowing of the grout and coal fracture plugging by migration and deposition of slurry particles was constructed. The crack distribution before and after the grouting of fractured coal samples was scanned with an industrial CT, and the fracture distribution of coal samples was reconstructed using an independently compiled MATLAB program. Meanwhile, the variations of the coal permeability before and after the grouting were tested. On this basis, this study built a numerical calculation model of the grouting in fractured coal samples to simulate the leakage stoppage and permeability reduction mechanism of the coal-based sealing material grouting. Results demonstrate that (1) according to the experimental test results, the new coal-based grouting materials achieve a good fracture plugging effect, and the fractures in coal samples after the grouting are filled densely by the grouting particles. (2) According to the simulation results, the permeability of grouting coal samples declines quickly and then tends to be stable. The overall permeability of coal samples and the fracture permeability are decreased by 93.5% and more than 99.9% in average, respectively. (3) Influences of the grouting pressure on the permeability variation of coal samples were investigated through a numerical simulation. It was found that a reasonable grouting pressure for coal samples is about 0.3 MPa. (4) The numerical simulation reproduces the whole process of the grout flowing and the fracture filling. The variation laws of the diffusion and the permeability of the grout which are calculated through a numerical simulation agree well with the experimental results, which verifies the reasonability of the model. Research conclusions can provide important significance in theory and practice to disclose the leakage stoppage and the permeability reduction mechanism of the borehole grouting during the gas extraction and strengthen the sealing effects of extraction boreholes.

The characteristics of the aerodynamic effects of high-speed trains passing in a shield tunnel were studied using the three-dimensional, compressible, unsteady Reynolds-averaged Navier-Stokes (RANS) equations for the simulation analysis. Numerical calculations were compared with dynamic model tests to verify the reliability of the numerical simulations. The results showed that the compression wave characteristics of high-speed trains in shield tunnels were consistent with those in molded concrete tunnels. When high-speed trains met in the middle of the shield tunnel, the positive and negative peak attenuation rates of shield tunnels were higher than the positive and negative peak attenuation rates of molded lining tunnels, and the maximum pressure attenuation rate could reach 57.8%. At the same time, the micro-pressure wave of the former was reduced by 10.78%, compared with those of the latter. When meeting cars at different locations, the maximum pressure at the intersection in the center of the tunnel was significantly higher than those at other intersection points in the tunnel. Different intersection positions and different tunnel lining structures had relatively little influence on the aerodynamic drag and lateral force, while train speed had a significant influence.

Evacuated Tube Transportation (ETT) reduces aerodynamic drag and energy consumption by lowering gas pressure around high-speed trains (HSTs). To optimise this effect, integrating the ETT system into high-speed cruise segments is a practical approach, though it may introduce vacuum potential energy losses. To address this, the paper put forward a Divided Evacuated Tube Transportation (D-ETT) system to seamlessly connect open-line and tube operation of HST then the regulations of aerodynamic energy consumption were studied. Theoretical discussions into reasonable parameter range including tube design and HST operation manners were conducted and then formed system-designing strategy. The spatial and temporal distribution law of tube gas circumstances were examined through model testing and numerical simulation. Three-dimensional, unsteady and compressible fluid models were established using Large Eddy Simulation (LES) to analyse tube fluid characteristics. Relative results indicated that under reasonable D-ETT designing strategies with larger blockage ratios, higher HST speeds, larger total mileage and mileage ratio of the mid-section, the aerodynamic energy saving effect is more impressive. The mixing of the adjacent tube gases with differential pressure induced gas-mixing fluctuations then changed the fluid circumstances inside the tube. The positional relationship between HST and gas waves infected aerodynamic energy consumption. By figuring out the spatiotemporal variation of tube gas, the theoretical energy estimation scheme for aerodynamic energy consumption with various cases was put forward, then the rationality and accuracy of which was verified by numerical simulation with prediction error less than 8%. The saving ratio of aerodynamic drag energy consumption of a 10 km tube could be 39.9% compared to traditional tunnels, which will be higher under ultra-long mileage, thus realising the overall aerodynamic energy saving effect. High-amplitude pressure waves intensified the pressure changes around HSTs, making it necessary to use HST capsules with superior sealing performance to ensure eardrum comfort.

The combination of real-time computed tomography (CT) scanning test and loading test can visualize the evolution process of defects such as internal pores and fissures in the coal. The axial deformation of the loaded coal sample will change the layers of the same section in the real-time CT scanning test, which will affect the analysis of fracture progression. To address the concern, we presented a CT image similarity retrieval method. The dynamic development law of fracture networks under triaxial stress was investigated using image processing technologies. The results reveal that the CT images of the coal sample in the same section can be obtained using the proposed CT image similarity retrieval method, which can more accurately characterize the fracture distribution and dynamic evolution law. The coal sample under triaxial stress experienced three fracture evolution stages: the closure in the compaction and elastic stages, the initiation and development in the plastic yield stage, and the rapid expansion and penetration in the postpeak stage. The variation trend of two-dimensional fracture ratio and fracture volume was consistent. The analysis is conducive to clarifying the coal failure mechanism under triaxial stress.