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Abstract Under the condition that the working face was directly covered with hard roof, the abrupt breaking of hard roof release significant amount of energy, thus prone to triggering dynamic disasters such as roadway instability or rockburst. This paper based on the engineering background of the Xieqiao Coal Mine's 11,618 working face, a numerical simulation method was put forward to study the dynamic response of roadway under the disturbance of hard roof breaking and proposed an evaluation index I C for roadway stability. Research indicates that the elastic energy released during the periodic weighting of the hard roof is higher than that released during the first weighting. Under the dynamic disturbance caused by hard roof breaking, the peak stresses of the roadway was slight decreased, accompanied by a significant increase in the range of stress concentration and plastic zone expansion. Roadway deformation patterns are significantly influenced by hard roof breaking, with noticeable increases in deformation on the roof and right side. During the period of hard roof breaking, the possibility of instability of the roadway increase significantly due to the disturbance caused by the dynamic load. The research results reveal the instability mechanism of roadway under the condition of hard roof, and provide a more reliable basis for evaluating the stability of roadway.

The drilling identification technology of surrounding rock lithology can obtain the mechanical parameters of the surrounding rock of the roadway in real time, providing the basic guarantee for the surrounding rock support of the coal mine roadway. Based on the hydraulic anchor drilling rig for coal mine roadways, this paper developed the drilling parameter acquisition system of hydraulic anchor drilling rig in coal mine roadways, including the drilling system, power system, monitoring system and specimen platform. Drilling experiments of combined specimens of mortar of different strengths were carried out using this system. The experimental results indicate that the system shows good performance, obvious variation of the parameters with drilling, and obvious transitions of torque and propulsion pressure at the junction of different rock formations. In order to verify the feasibility of identifying rock strength while drilling, this study calculated the relationship between rock breaking specific energy by means of drilling parameters, and also analyzed the relationship between drilling parameters and compressive strength, it shows that based on the rock breaking specific energy method, the system can realize the identification of rock mechanical parameters by drilling parameters.

MicroRNAs (miRNAs) can participate in plant-insect interactions, which regulate plant defense networks. In this study, we analyzed the miRNA expression profiles of six rice varieties before and after brown planthopper (BPH)-feeding. We identified 45 differentially expressed miRNAs between BPH- susceptible and BPH-resistant rice varieties and 144 miRNAs that responded to BPH-feeding. Thus, miRNAs may be involved in multiple pathways regulating rice defense response against BPH. In addition, we found that the genetic history of rice varieties determined the regulation mode of the miRNA and affected the amounts, types, changing trends and response periods of miRNAs in response to BPH- feeding. To conclude, we scanned seven potential cross-kingdom miRNAs, of which miR5795 may target the vitellogenin gene in BPH, causing a 16.07% reduction in BPH oviposition. The results provide new miRNA information of rice-BPH interactions and BPH-resistant rice variety breeding.

C14H4O2S4, monoclinic, P21/n (no. 14), a = 3.85180(10) Å, b = 8.9728(2) Å, c = 18.0073(4) Å, β = 93.554(1)°, V = 621.16(3) Å3, Z = 2, R gt(F) = 0.0411, wR ref(F 2) = 0.1091, T = 301(2) K.

Owing to the increasing need for green synthesis and environmental protection, the utilization of biological organism‐derived carbons as supports for noble‐metal electrocatalysts has garnered public interest. Nevertheless, the mechanism by which microorganisms generate nanometals has not been fully understood yet. In the present study, we used genetically engineered bacteria of Shewanella oneidensis MR‐1 (∆SO4317, ∆SO4320, ∆SO0618 and ∆SO3745) to explore the effect of surface substances including biofilm‐associated protein (bpfA), protein secreted by type I secretion systems (TISS) and type II secretion systems (T2SS), and lipopolysaccharide in microbial synthesis of metal nanoparticles. Results showed Pd/∆SO4317 (the catalyst prepared with the mutant ∆SO4317) shows better performance than other biocatalysts and commercial Pd/C, where the mass activity (MA) and specific activity (SA) of Pd/∆SO4317 are 3.1 and 2.1 times higher than those of commercial Pd/C, reaching 257.49 A g−1 and 6.85 A m−2 respectively. It has been found that the exceptional performance is attributed to the smallest particle size and the presence of abundant functional groups. Additionally, the absence of biofilms has been identified as a crucial factor in the formation of high‐quality bio‐Pd. Because the absence of biofilm can minimize metal agglomeration, resulting in uniform particle size dispersion. These findings provide valuable mechanical insights into the generation of biogenic metal nanoparticles and show potential industrial and environmental applications, especially in accelerating oxygen reduction reactions. [ABSTRACT FROM AUTHOR]