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Based on the geological condition of Luohe Formation sandstone aquifer above the deep working face of 4# coal in Gaojiapu Mine, Binchang Mining area, the relationship between aquifer and dynamic disaster breeding is discussed. Firstly, the formation and its setting condition of the aquifer above 4# coal seam are introduced. Based on field water inflow monitoring data, we examined the relationship between the resistance of the support and the change of water inflow. The temporal and spatial correlation between micro seismicity and water movement is analyzed and identified, which will offer significant value for the early-warning of the dynamic hazards and water inrush. We expound the dynamic and static load of confined water movement on the working face after the increase of water inrush, and point out that it is important to pay more attention to the dynamic disaster risk of the working face after the water surge.

Purpose: Autostereoscopic displays have become increasingly common, but their impact on ocular dimensions remains unknown. We sought to identify changes in the crystalline lens dimensions induced by autostereoscopic three‐dimensional (3D) viewing. Methods: Forty young adults (age: 22.6 ± 2.0 years, male/female: 15/25) were consecutively enrolled and randomly divided into two groups (3D and two‐dimensional [2D] viewing groups) to watch a 30‐min movie clip displayed in 3D or 2D mode on a tablet computer. The lens thickness (LT), diameter, curvature, decentration and tilt were measured with anterior segment optical coherence tomography under both non‐accommodating (static) and accommodating conditions. Results: In the static condition, the LT decreased by 0.03 ± 0.03 mm (p < 0.001) and the anterior radius of curvature (ARC) increased by 0.49 ± 0.59 mm (p = 0.001) post‐3D viewing. In contrast, following 2D viewing, the ARC decreased by 0.23 ± 0.25 mm (p = 0.001). Additionally, the increase in the steep ARC post‐3D viewing was greater in high‐myopic eyes than low to moderate myopic eyes (p = 0.04). When comparing the accommodative with the static (non‐accommodative) condition, for 3D viewing the lens decentration decreased (−0.03 ± 0.05 mm, p = 0.02); while for 2D viewing, the posterior curvature radius (−0.14 ± 0.20 mm, p = 0.006) and diameter (−0.13 ± 0.20 mm, p = 0.01) decreased. Conclusions: Viewing with the autostereoscopic 3D tablet could temporally decrease the thickness and curvature of the lens under non‐accommodating conditions. However, its long‐term effect requires further exploration. [ABSTRACT FROM AUTHOR]

In this study, the microstructural evolution of a Ti-15Mo medical alloy was investigated, when the in situ cyclic tensile strain had 2% amplitude and the tension–compression cyclic deformation had 1%, 2%, and 3% amplitude. The Vickers hardness and wear resistance of the alloy were also optimized due to the grain-refining effect after cyclic deformation and annealing. The twinning-induced plasticity (TWIP) was considered the main deformation mechanism of the Ti-15Mo alloy during the tensile–compressive cycle deformation with suitable strain amplitude. The {332}<113> twins and boundaries were the main contributors to the grain refinement. The optimal microstructure, hardness, and wear resistance were obtained in the alloy deformed by tension–compression cyclic strain with a 3% strain amplitude. The wear resistance of the annealed alloy in Hank's solution was excellent in contrast to the original Ti-15Mo alloy due to its reasonable microstructure and hardness. It is clear that abundant twins were formed and retained in the coarse grains of the original alloy after cyclic deformation and annealing, which provided the expected refined grains and performance. [ABSTRACT FROM AUTHOR]

2-Amino-4-hydroxypteridine (pterin) and its derivatives serve as photooxidants and exhibit strong fluorescence. When they interact with hydrogen acceptors such as acetate and phosphate, their fluorescences are significantly quenched in acidic conditions (pH 4.9-5.5) but are retained in basic conditions (pH 10.0-10.5). This pH-related fluorescence quenching mechanism of pterin and its derivatives are fully investigated by using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Pterin and its derivatives are demonstrated to show favorable excited-state proton transfer (ESPT) abilities in acidic conditions that induce the experimentally observed fluorescence quenching. In contrast, the ESPT processes are found to be retarded due to the lack of strong hydrogen-bonding interactions in basic environments, which sustain their fluorescence. Interestingly, these ESPT processes are found to show different site specificities depending on the 6-site substituents. The introduction of electron-donating substituent activates the N1 site, making it the preferred ESPT site. By contrast, the introduction of an electron-withdrawing substituent activates the N5 site, making it the favorable ESPT site. The substitutions of different functional groups are found to affect the locations of acidic centers during the excitation and relaxation processes. This further affects the hydrogen-bonding patterns and ultimately brings site specificity to the ESPT process. Key words: pH-related fluorescence quenching, site-specific excited-state proton transfer, time-dependent density functional theory, substituent effect. La 2-amino-4-hydroxypteridine (pterine) et ses derives, qui sont employes comme photo-oxydants, presentent une forte fluorescence. Lorsqu'ils interagissent avec des accepteurs d'hydrogene tels que l'acetate et le phosphate, leur fluorescence subit une extinction importante en conditions acides (pH 4,9 a 5,5) alors qu'elle est maintenue en conditions basiques (pH 10,0 a 10,5). Nous avons etudie en detail ce phenomene d'extinction de la fluorescence liee au pH pour la pterine et ses derives a l'aide de la theorie de la fonctionnelle de la densite (DFT) et de sa variante dependante du temps (TD-DFT). La pterine et ses derives ont presente des capacites favorables de transfert de proton a l'etat excite (TPEE) en conditions acides, lesquelles induisent l'extinction de fluorescence observee experimentalement. En revanche, on observe un retard des processus de TPEE dans les milieux basiques, en raison de l'absence de liaisons hydrogene fortes dans ces conditions, lesquelles maintiennent la fluorescence. Faitinteressant, on remarque que ces processus de TPEE presentent une specificite pour differents sites selon la nature des substituants en position 6. L'ajout d'un substituant electrodonneur active le site N1, ce qui en fait le site privilegie pour le TPEE. A l'inverse, l'ajout d'un substituant electroattracteur active le site N5, le rendant ainsi le plus favorable au TPEE. Nous avons observe que la substitution par differents groupes fonctionnels influe sur la position des centres acides durant les processus d'excitation et de relaxation et, par ricochet, sur l'arrangement des liaisons hydrogene, ce qui confere ultimement au processus de TPEE une specificite de site. [Traduit par la Redaction] Mots-cles: extinction de la fluorescence liee au pH, transfert de proton a l'etat excite specifique d'un site, theorie de la fonctionnelle de la densite dependante du temps, effet des substituants., Introduction As a group of heterocyclic compounds, pterin and its derivatives (pterins) exist extensively in living organism and are generally believed to bring photodamages to bio-molecules including DNA, (1,2) enzymes, [...]