Experiment of Electrical Fire Burned Copper Wire and Parameters Analysis on Metallographic Test of Melted Mark

AbstractHeat treatment experimental simulation of the actual situation of the electrical fire melted mark was carried out; the metallograph of copper wire after heating was obtained, and verified with the actual case. And then using digital image processing software to grain size, that in a certain temperature range, the relation between average size and heated temperature was curve; particle size increases with the increase of heating time; water cooling, air cooling, furnace cooling conditions, the grain increases by followed

Passive Continuous Particle Focusing in a Microchannel with Symmetric Sharp Corner Structures

We report a continuous passive particle focusing method using a novel microchannel with symmetric sharp corners which induce curved streamlines and large centrifugal force on particles. At appropriate flow rate, the centrifugal force generated on particles exceeds the inertial lift force; particles driven by the centrifugal force migrate toward the center of the microchannel, achieving continuous particle focus-ing. With simple structure and operation, this method can be potentially used in particle focusing and ex-traction processes in a variety of lab-on-a chip applications

Early warning technique research of surface subsidence for safe mining in underground goaf in Karst Plateau zone

Underground mining in Karst Plateau landform area may cause the loss of support for the upper rock stratum, resulting in rock collapse and large-scale subsidence of the ground surface. Also, the formation of a large-scale goafs may further lead to geo-hazards such as collapse, water gushing, slope instability and so on in the area. To reduce the impact of goaf settlement on local strata stability, this paper established a standardized safe mining detection model for goafs based on the geological safety characteristics of mining goafs. With reference to the statistical analysis of the geological conditions in the mining area, a numerical model with 358 goafs and the proposed mining area was established using FLAC3D numerical software. The surface subsidence and variations of plastic zone in the mining area were comprehensively analyzed. The results indicated that there was a correlation between the stability of the mining area and the geological occurrence conditions of the goafs. By quantitatively taking the values from standardized safety mining detection models, the standardized safety mining detection and warning technique was finally established. The findings can provide technical guidance for safety detection and early warning in the whole process of underground goaf mining in Karst Plateau karst development zone

1-[4-(4-Chloro­but­oxy)-2-hy­droxy­phen­yl]ethanone

In the title compound, C12H15ClO3, the eth­oxy group is nearly coplanar with the benzene ring, making a dihedral angle of 9.03 (4)°, and is involved in an intra­molecular O—H⋯O hydrogen bond to the neighbouring hy­droxy group