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The conventional reflective optical surface with adjustable reflection characteristics requires a complex external power source. The complicated structure and preparation process of the power system leads to the limited modulation of the reflective properties and difficulty of use in large-scale applications. Inspired by the biological compound eye, different microstructures are utilized to modulate the optical performance. Convex aspheric micromirror arrays (MMAs) can increase the luminance gain while expanding the field of view, with a luminance gain wide angle > 90° and a field-of-view wide angle close to 180°, which has the reflective characteristics of a large gain wide angle and a large field-of-view wide angle. Concave aspheric micromirror arrays can increase the luminance gain by a relatively large amount of up to 2.66, which has the reflective characteristics of high gain. Industrial-level production and practical applications in the projection display segment were carried out. The results confirmed that convex MMAs are able to realize luminance gain over a wide spectrum and a wide range of angles, and concave MMAs are able to substantially enhance luminance gain, which may provide new opportunities in developing advanced reflective optical surfaces. [ABSTRACT FROM AUTHOR]

High-temperature coal oxidation generates a substantial amount of CO and CO2, especially CO, rapidly, which is a primary factor leading to casualties. The oxygen concentration is the predominant factor affecting the high-temperature oxidation of coal, particularly in the generation of CO and CO2. Understanding the generation patterns and relationship characteristics of CO and CO2 under various oxygen concentrations is important for predicting high-temperature coal oxidation and ensuring personnel safety. The paper used TG–MS and FTIR to study the formation characteristics of isothermal oxidation of CO and CO2 in long-flame coal under different oxygen concentrations. The results indicate that there exists an optimal threshold for CO production when the oxygen concentration is about 9% during the isothermal temperature oxidation process at 200.00–350.00 °C. When the oxygen concentration is less than 13%, the influence of oxygen on CO2 production is weakened. As the temperature increases, the pattern of CO + CO2 production and CO/CO2 is reversed, with CO + CO2 increasing and CO/CO2 decreasing. The relationship between the total production of CO and CO2 and the loss of coal mass follows the function y = a + bx at the isothermal temperatures of 300.00 °C and 350.00 °C. An increase in oxygen concentration does not alter the linear relationship. In the isothermal oxidation process of coal, carbonyl and carboxyl groups are the key groups for CO and CO2 production. At 200.00 °C and 250.00 °C, carbonyl and carboxyl groups increase, and other groups are being converted to carbonyl and carboxyl groups while decomposing into CO and CO2. At 300.00 °C and 350.00 °C, the relative content of carboxyl groups decreases. The research findings play a fundamental role in coal mine disaster prevention and control. [ABSTRACT FROM AUTHOR]

In view of problems of poor fluidity, unsatisfactory fire-extinguishing effect and high cost of existing mine-used anti-fire extinguishing resistant material,inorganic clay composite superabsorbent resin was synthesized by aqueous solution polymerization method, and its structural characterization and thermal stability were measured. The resistive properties were studied combined with heating process of coal spontaneous combustion. The results of infrared spectrum and thermal stability analysis show that the prepared composite superabsorbent resin has main functional group with high water absorption characteristics and high thermal stability. The coal samples were treated with CaCl2, ascorbic acid and composite superabsorbent resin to resist the oxidation, and the oxidation kinetics and index gas tests were carried out on the coal samples after the inhibition. The results show that compared with the raw coal, CaCl2 and ascorbic acid resistant coal sample, composite superabsorbent resin resistant coal sample has the smallest oxygen consumption when the temperature of coal sample reaches 70 °C, and its intersection temperature is the highest, the initial temperature required to produce CO and CO2 is higher, which indicates that the composite superabsorbent resin has better inhibition effect on coal spontaneous combustion.

In order to master development and evolution law of cable fire in coal mine chamber, FDS software was used to simulate smoke flow, carbon monoxide concentration, oxygen concentration and temperature during development process of cable fire in coal mine chamber. The results show that: ① With increase of time of cable fire in coal mine chamber, smoke flow will accelerate to spread the whole chamber; carbon monoxide concentration increases firstly, then decreases and finally tends to be stable; oxygen concentration decreases firstly, then increases and finally tends to be stable; temperature increases firstly, then decreases and finally approaches initial temperature. ② Concentration of carbon monoxide and oxygen in return airway fluctuates violently, and temperature fluctuation is relatively small, while carbon monoxide concentration, oxygen concentration and temperature in air inlet roadway are not affected by fire, so the air inlet roadway can be used as a safe escape route. ③ Within 60 s after the fire occurs, smoke flow has a small spreading range and concentrates in middle-upper part of chamber, and carbon monoxide concentration, oxygen concentration and temperature are all within safe range. The best time to escape is within 60 s after the fire occurs.

Purpose: To compare the diagnostic performance of the capillary density (CD) of the central 1–6 mm and peripheral 6–12 mm annular regions in detecting open‐angle glaucoma in high myopia (HM) using 15 × 12 mm wide‐field swept‐source optical coherence tomography angiography (WF SS‐OCTA). Methods: The study enrolled 206 and 103 eyes with HM and highly myopic open‐angle glaucoma (HM‐OAG), respectively. WF SS‐OCTA images centred on the fovea were obtained to analyse the changes in the CD in the 1–3 mm, 3–6 mm, 6–9 mm, and 9–12 mm annular regions. CD of the superficial capillary plexus (SCP) was measured with the built‐in software. The area under the receiver operating characteristic curve (AUROC) of each region was compared. Results: The diagnostic performance of the SCP CD in the central 1–6 mm annular region (AUROC = 0.849) was better than that in the peripheral 6–12 mm annular region (AUROC = 0.756, p = 0.001). The annular AUROCs of SCP CD peaked in the 3–6 mm annular region (AUROC = 0.858) and gradually decreased with increasing diameter and were lower than the corresponding AUROCs of the ganglion cell–inner plexiform layer thickness (p < 0.05 for all comparisons). SCP CD of the inferior quadrant in the 3–6 mm annular region had the best diagnostic performance (AUROC = 0.859). Conclusion: The SCP CD in the central 1–6 mm annular region exhibited better diagnostic performance for the detection of HM‐OAG in HM. The assessment of more peripheral regions has no added value in detecting glaucoma in HM. [ABSTRACT FROM AUTHOR]