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This paper takes the deep ore body of Yunnan Phosphate Group Co. Ltd, the largest open-pit chemical mining enterprise in China, as the research background, and systematically introduces the technical problems recognised by many Chinese researchers in the past eight years on the open-pit to underground mining of gently inclined thin to medium-thick ore bodies with a soft interlayer. It shows that the mining of open-pit transferred to underground is a complex engineering system, and the underground stope surrounding rock and overlying strata present a nonlinear failure process. Through mining process innovation, mining method innovation and improvement, research was undertaken on new processes and technologies for phosphorus mining under complex conditions. The relevant research results not only have important economic value and academic significance for Yunnan Phosphate Group Co. Ltd. but also have important guidance and impetus to the exploitation of a large number of similar phosphate resources in China.

In order to investigate the response law of moisture content to the characteristic stress and acoustic emission characteristics of red sandstone, the uniaxial compression tests of red sandstone under different moisture content conditions were conducted using RMT-150C rock mechanical pressure testing machine and PCI-Ⅱ AE win acoustic emission system. The physical and mechanical parameters and characteristic stress evolution mechanism of red sandstone under water erosion are analyzed, and the evolution law of acoustic emission (wide and narrow-band) time series mode under different moisture content conditions is also investigated. At the same time, the damage evolution model of red sandstone is constructed based on cumulative acoustic emission event number and statistical mechanics theory. The results show that: 1) The P-wave velocity decreases first and then increases with the increase of moisture content. When the water saturation reaches a critical value, the P-wave velocity will drop to the lowest value. 2) The acoustic emission signal received by the narrow-band receiving sensor is closely related to the friction between the particles in the red sandstone, and the acoustic emission signal received by the wide-band receiving sensor is intrinsically related to the evolution of the internal cracks in the red sandstone. 3) The moisture content has a significant effect on the acoustic emission event rate (wide-band) at the stage of unstable crack propagation, and has a minor effect on the ratio of characteristic stress to peak strength, but it has a relatively obvious effect on the strain percentage at each stage. With the increase of moisture content, the failure mode of red sandstone specimens gradually changes from brittle failure to ductile failure. 4) As the moisture content increases, a "backward" change trend can be observed for the active period of acoustic emission event rate (narrow-band), and the acoustic emission modes of dry, natural, and saturated rock samples correspond to mass shocks, pre-main-later shocks and swarm shocks type, respectively. (5) According to the damage model based on the cumulative number of acoustic emission events (wide and narrow-band), the damage process of red sandstone can be divided into four stages: initial damage stage, stable damage development stage, accelerated damage development stage and damage destruction stage.

This research aimed to determine the dynamic endogeneity nexus among energy consumption (EC), financial development (FD), foreign direct investment (FDI), globalization (GI), and urbanization (URBAN). The study used 64 countries’ annual panel data on “the Belt and Road Initiative (BRI)” from 2009 to 2019. Moreover, it employed a two-step system GMM, robust and results, that indicates financial development and urbanization are positively correlated with energy consumption, suggesting that these two factors raise the energy demand. Contrastingly, globalization negatively impacts energy demand, implying that global connectivity is essential for BRI countries. Foreign direct investment (FDI) has a positive but insignificant connection with energy consumption. Additionally, the Granger causality test was employed to explore the causal association among the variables, and outcomes reveal a bidirectional causal connection between FD and energy consumption. The study also suggests sustainable energy policy implications, which will be helpful to policymakers and governments for ensuring a balanced, sustainable growth.JEL Code: P48; P25; Q4; F6; G00; E2

This study examines the issues of privacy protection, data security, and query efficiency in blockchain-based electronic medical record (EMR) sharing. It proposes a secure storage and sharing scheme for EMR based on Hyperledger Fabric and the InterPlanetary File System (IPFS). To mitigate the privacy risks of data mining that could reveal patient identities, we establish an attribution channel in Hyperledger Fabric to store EMR ownership information and a data channel to store the storage location, digest, and usage records of medical data. Encrypted medical data are stored in the IPFS. To improve query efficiency in the blockchain, we integrate queryable medical data attributes into a composite key for conditional queries, avoiding complex data filtering processes. Additionally, we use a zero-knowledge proof combined with smart contracts for decentralized identity verification, eliminating reliance on third-party centralized verification services and enhancing system security. We also integrate AES and proxy re-encryption techniques to ensure data security during sharing. This scheme provides a more secure, efficient, and privacy-preserving approach for EMR systems, with significant practical implications and broad application potential. [ABSTRACT FROM AUTHOR]

Deep‐blue perovskite light‐emitting diodes (PeLEDs) based on quasi‐two‐dimensional (quasi‐2D) systems exist heightened sensitivity to the domain distribution. The top‐down crystallization mode will lead to a vertical gradient distribution of quantum well (QW) structure, which is unfavorable for deep‐blue emission. Herein, a thermal gradient annealing treatment is proposed to address the polydispersity issue of vertical QWs in quasi‐2D perovskites. The formation of large‐n domains at the upper interface of the perovskite film can be effectively inhibited by introducing a low‐temperature source in the annealing process. Combined with the utilization of NaBr to inhibit the undesirable n=1 domain, a vertically concentrated QW structure is ultimately attained. As a result, the fabricated device delivers a narrow and stable deep‐blue emission at 458 nm with an impressive external quantum efficiency (EQE) of 5.82 %. Green and sky‐blue PeLEDs with remarkable EQE of 21.83 % and 17.51 % are also successfully achieved, respectively, by using the same strategy. The findings provide a universal strategy across the entire quasi‐2D perovskites, paving the way for future practical application of PeLEDs. [ABSTRACT FROM AUTHOR]

Retaining wall is essential for stopes mining in two steps, for it can prevent the instability and collapse of backfill. In this study, taking the retaining wall of backfilled stope as the research object, a stability analysis method of retaining wall based on the close coupling of catastrophe theory and numerical analysis was proposed. First, by extracting the unit failure rate of the retaining wall from the numerical simulation results and fitting it with the mining depth, the functional expression between them was established. Second, the function relation was transformed into the normal form according to catastrophe theory, and the instability criterion of retaining wall was deduced. Furthermore, an effort was made to analyze the changing law of the state of retaining wall and calculate the critical span of stope, under different thickness conditions. On this basis, the application test of retaining wall was carried out by using this method. The results show that with the thickness decreasing, the values of splitting variables a and b show a reverse trend, which leads to the discriminant of instability criterion decreasing and turning from positive to negative, resulting in the collapse. Meanwhile, in order to ensure the stability, the wider the span of the stope, the thicker the retaining wall is required, and conversely, the thicker the retaining wall, the higher the adaptability to the span of stope. In addition, it can be found from the application test that instability was bound to occur with a thickness of 3 m, but the retaining wall with a thickness of 4 m maintained stable, which tended to be consistent with the analysis. Therefore, the stability analysis method proposed in this study provides a way to accurately evaluate the stability of the retaining wall and calculate the critical thickness of that, and its application value is expected to be further explored. [ABSTRACT FROM AUTHOR]

The inflow uniformity before selective catalytic reduction (SCR) catalyst carrier is a major issue for DeNOx capability of diesel engine after-treatment. Through the construction of the numerical model and CFD simulation of six perforated plate variations with different structural and positional characteristics, the influence of perforated plates on the uniformity of the airflow velocity at the inlet of the SCR catalyst carrier was analyzed. Comparison of different perforated plate variations shows that the encircling flow is a major hindrance to achieve higher inflow uniformity. Enclosed flow passage can remove the encircling flow and increase inflow uniformity at the cost of increased pressure drop. Rational layout of the perforated plate can achieve uniformity increase, while decrease pressure drop. High-velocity exhaust coupled with larger holes can improve both uniformity and pressure drop. The uniformity index increased from 97.6% of the original design to 98.7% of the optimized design, while pressure drop increased from 11.20 to 12.09 kPa. Weighing the relationship between inflow uniformity and pressure drop is an issue worthy of attention.