Both the deformation characters and the failure mode of the large cross-sectional longwall installation roadway under compound roof are becoming an emergent issue than ever before due to the rapid development of modern mining equipment. Various engineering applications have revealed that the insufficient design and inappropriate support technology are the main reasons for the fatal accidents as...

The effects of 20 MeV proton irradiation with fluences 5 × 1014 and 1015 p/cm2 on electrical properties lightly Sn doped n-type (net donor concentration 3 1017 cm?3) bulk ?-Ga2O3 samples (010) (?201) orientation were studied. Proton decreases the net density a removal rate close to 200 cm?1 for both orientations similar electron rates in Si epilayers. main deep traps introduced crystals are nea...

We study the structural instability mechanism and effect of a multi-echelon support in very-deep roadways. We conduct a scale model test for analysing the structural failure mechanism and the effect of multi-echelon support of roadways under high horizontal stress. Mechanical bearing structures are classified according to their secondary stress distribution and the strength degradation of the s...

During the mining process of fully-mechanized caving faces, roof roadway behind working face easily forms an arched-shape hanging structure with pushed forward, which results in potential hazards such as gas accumulation and large-scale collapse. Based on actual situation a at difficult end top coal through borehole exploration, surrounding rock displacement observation, bolt stress monitoring,...

in order to evaluate the effects of sub soiling and irrigation level treatments on yield of sugar beet and wheat in rotation, an experiment was conducted at agricultural research station ofwest azerbaijanprovince. the plots were arranged as a strip plot experiment in randomized complete block design with three replications. horizontal plot (sub soiling treatment) consisted of sub soiling depth ...

We estimate the number of old, radiative supernova remnants (SNRs) detectable in Hi 21-cm emission line in the Galaxy. We assume that old SNRs consist of expanding Hi shells and that they are visible if the line-of-sight velocities are sufficiently outside the velocity range of the Galactic background Hi emission. This criterion of visibility makes it possible to calculate the background contam...

In the process of coal seam mining, there are often hard thick key layers in overlying strata. Due to high strength and good integrity layer, after layer is broken, strata will collapse lose stability a large area, which very easy induce dynamic disasters such as rock burst, mine earthquake, wall caving, roof slab caving. Aiming at working face, response under strong earthquake induced by break...