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nondestructive detection, [2] material identification, [3] biomedical sensing, [4] to the emerging sixth generation (6G) communications, [5] in which THz absorbers with high absorption intensity (>99%) in a large qualified bandwidth are urgently demanded. THz absorber can be widely used in THz emitting/detecting antennas to reduce the sidelobe radiation or any undesirable radiation, or in the whole THz systems to suppress the electromagnetic interference (EMI). [6,7] Another potential use is for radar cross-section (RCS) reduction, which can reduce radar echo to achieve a greater element of stealth. [8] Considering that THz imaging system has already been commercialized, [9,10] THz communication have been officially designated for 6G network, [11-13] and even the prototype of THz radar have been demonstrated for concealed weapon detection, [14-16] there is being an urgent and huge demand of high-intensity absorption, broadband, and low cost THz absorber in both military and civilian aspects. Generally, condensed materials with higher conductivity inherently have higher electromagnetic (EM) loss, which, however, does not guarantee a stronger absorption because higher conductivity in turn leads to stronger reflection at the surface of material. When EM wave radiates from free space to a condensed material, the reflection from the surface is nearly inevitable to occur unless the impedance matching is achieved,

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Silver nanowires (AgNWs) show promise for fabricating flexible transparent conductors owing to their excellent conductivity, high transparency, and good mechanical properties. Here, we present the fabrication of transparent films composed of AgNWs with diameters of 20–30 nm and lengths of 25–30 μm on polyethylene terephthalate substrates and glass slides substrates using the Meyer rod method. We systematically investigated the films’ optoelectronic and electrothermal properties. The morphology remained intact when heated at 25–150 °C and the AgNWs film showed high conductivity (17.6–14.3 Ω∙sq−1), excellent transmittance (93.9–91.8%) and low surface roughness values (11.2–14.7 nm). When used as a heater, the transparent AgNW conductive film showed rapid heating at low input voltages owing to a uniform heat distribution across the whole substrate surface. Additionally, the conductivity of the film decreased with increasing bending cycle numbers; however, the film still exhibited a good conductivity and heating performances after repeated bending.

When faced with multi‐seam mining, some coal pillars are left to support the overlying strata when mining the lower seam, where stress concentration usually occurs. When the working face in the lower seam advances to the area influenced by these coal pillars, high ground pressure behavior occurs. Furthermore, the instability of coal pillars under the participation of the roof may induce rock burst, which threaten the safe production of coal mine. To study the roof strata movement and coal pillar instability in multi‐seam mining, a coal mine in Datong was taken as an example. Firstly, the bursting liability of coal and rock stratum was tested. The test results show that the 7#, 8#, and 11# coal seams in the mining area all have strong bursting liability. And the roof was dominated by siltstone and firestone, which also have strong bursting liability. Then, based on the geological conditions of the coal mine, we investigated roof movement and instability of the coal pillar during multi‐seam mining through physical simulation. The simulation results indicate that multi‐seam mining aggravates the roof damage, which leads to the increase in the fracture range of overlying strata, and that the failure height increases from 46 to 121 m. In addition, the detailed distribution of stress on residual coal pillars and its influence on the lower working face were studied through numerical simulation. The results show that, when the working face 8707 of the 8# coal seam advances to a horizontal distance of 20 m from the coal pillar, it enters the influence zone. As the working face advances beneath the coal pillar, the stress reached to 24 MPa. Moreover, when the working face passes by the coal pillar, the coal pillar is cutoff, thus affecting the working face.

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