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As coal mining operations continue to deepen, the frequency of coal spontaneous combustion (CSC) and gas explosion disasters in high-gas mines is increasing. Understanding the distribution patterns of CSC and gas compound disaster zones in the gob during the extraction process is crucial for reducing the risks of combustion and explosion. This study focuses on the 201 working face of the Shuanglong Coal Mine, where a multi-physical field coupling model of pressure, temperature, gas seepage, and diffusion was established to investigate the evolution characteristics of compound disaster zones and propose corresponding prevention and control measures. The results demonstrate that the area with the most severe composite hazard is mainly located at the return roadway side, extending to the middle of the gob. With increased ventilation volume and advance rate, the area of the CSC and gas coupling hazard zone expands continuously. By implementing measures such as brattice cloth and nitrogen injection, the areas of spontaneous combustion and CH4 explosion zones were reduced by 53.6 % and 49.5 %, respectively, effectively controlling the extent of the compound disaster zone and eliminating the risk of gas explosions.

To study the oxidation behavior induced by the spontaneous combustion of accumulated pulverized coal during its storage and transportation within an air leakage circumstance during increased oxidation and temperature and to reveal the mechanism of [BMIM][BF4] ionic liquid inhibiting oxidation and flame retardant characteristics of pulverized coal, this paper used a high-efficiency inhibitor [BMIM][BF4] ionic liquid to inhibit the noncaking coal pulverized coal of the Hongliu coal mine (HL), measuring the critical parameters (critical spontaneous combustion temperature, Tm, and ignition delay time, ti) of pulverized coal spontaneous combustion treated using [BMIM][BF4] at 5%, 10%, and 15% mass fraction. This work also analyzed the influence of [BMIM][BF4] on the heating and self-heating of the pulverized coal. Macroscopic resistance characteristics of [BMIM][BF4] to the pulverized coal were tested under the same high-temperature circumstance (all pulverized coals were ignited). Furthermore, an Fourier transform infrared experiment was used to characterize the microscopic resistance characteristics of the pulverized coal by [BMIM][BF4] to verify the variation of the critical parameters during pulverized coal spontaneous combustion. Results show that [BMIM][BF4] can efficiently inhibit the self-heating reaction of the pulverized coal, increase the Tm and ti values of the pulverized coal, and reduce the risk of pulverized coal spontaneous combustion. Moreover, a higher [BMIM][BF4] mass fraction results in a greater critical parameter of pulverized coal spontaneous combustion. Among them, the Tm of the coal powder treated by [BMIM][BF4] at a 15% mass fraction is 156 ℃, which is +26 ℃ longer than the original pulverized coal redundancy, and the ti is 80 min, which is 32 min later than the original pulverized coal ignition. Under a similar experimental temperature, Ta (Ta>Tm), the center point temperature, oxygen consumption rate, and CO production of pulverized coal treated by [BMIM][BF4] are all lower than those of the original pulverized coal, and the inhibition effect is enhanced with the increase in the mass fraction of [BMIM][BF4]. Meanwhile, the inhibited effect of [BMIM][BF4] is reflected in the strong electronegative fluorine atoms forming strong hydrogen bonds with the hydroxyl hydrogen atoms in coal, dissolving and destroying the hydroxyl groups in the coal and blocking the coal oxygen chain reaction.

A new method of generating 1.57 µm multi-pulse eye-safe laser based on optical parametric oscillator (OPO) has been developed. The pulse repetition rates, pulse numbers and pulse intervals could be regulated. By analyzing the threshold of the OPO and optimizing the resonator parameters, pulse string laser outputs with adjustable repetition rates were obtained. Each pulse string includes three micro-pulses, and their intervals were greater than 200 µs. It was observed that when the interval of the micro-pulse was 236 µs, the maximum output energy of the pulse string was 158 mJ with the single pulse width of 6 ns. The optical-optical efficiency of the OPO was 30.5% [ABSTRACT FROM AUTHOR]

Trophic dynamics is one of the major regulators of fishery production in marine ecosystems, which is important for the implementation of ecosystem-based fisheries management. Based on data collected form bottom trawl surveys in Haizhou Bay and adjacent waters during autumn of 2011 and 2018, Delta-GAMMs (Delta-generalized additive mixed models) were constructed to evaluate the effects of biotic and abiotic factors on the predation of five key prey species (including Leptochela gracilis , Alpheus japonicus , Loligo spp., Larimichthys polyactis , and Oratosquilla oratoria ) in the Haizhou Bay. Percent frequency of occurrence and predation pressure index were used to identify their major predators. Variance inflation factor and full subsets regression were analyzed to quantify the degree of multicollinearity between these factors. The results showed that the occurrence frequency of keystone prey species in the stomach of predators ranged from 8.5% to 42.2%, and the weight percentage ranged from 4.2% to 40.9%. The average deviance explanation rate of the "binomial" model was 16.1%, and the average deviance explanation rate of the "positive" model was 23.8%. Body length of predator, predator population density, and sea bottom temperature were important factors influencing prey-predator trophic interactions. Predator length was the most important factor, with feeding probability and weight percentage of keystone prey species all increasing with body length of predator. Feeding probability and weight percentage of key prey species decreased with predator population density. The effects of environmental factors such as sea bottom temperature, depth of water, latitude, and sea bottom salinity showed different trends, depending on the prey-predator assemblage. This study showed that the Delta-GAMMs was an effective method to explore the trophic interactions between prey and predators in marine ecosystems, and could provide a theoretical basis for the conservation and sustainable use of fisheries resources.