| 1 | An analytic solution describing the visco-elastic deformation of coal pillars in room and pillar mine显示文摘Coal pillar deformation is typically nonlinear and time-dependent. The accurate prediction of this defor- mation has a vital importance for the successful implementation of mining techniques. These methods have proven very important as a way to excavate coal resources from under buildings, railways, or water bodies. Elastic and visco-elastic theory are employed with a Maxwell model to formulate an analytic solution for displacement of coal pillars in room and pillar mine. These results show that the visco-elastic solution adequately predicts the coal pillar deformation over time. We conclude that the visco-elastic solution can predict the coal pillar and roadway displacement from the measured geological parameters of the conditions in situ. Furthermore, this method would be useful for mine design, coal pillar support optimization, ground subsidence prediction, and coal pillar stability analysis. | Li Qiang XU Hui BU Wankui Zhao Guozhen | 2011 | Mining Science and Technology2011，21，6： | 5 |
| 2 | Effects of annealing condition and Al content on novel Fe_(73.5)Si_(13.5)B_9Cu_1Nb_(3-x)Al_x alloys显示文摘The annealing condition, Al content, and field amplitude dependences of the complex permeability for Nb-poor Finemet type alloys, Fe73.5Si13.5B9Cu1Nb3-xAlx (x = 0, 0.5, 1.5, 2.0, and 3.0), were investigated using an impedance analyzer and X-ray diffraction. The results show that different Al contents lead to different optimum annealing conditions, and the Al content exerts a distinct effect on microstructure thus resulting in a variety of real permeability value. For the samples annealed at 793 K for 0.5 h, the real permeability increases with an in- crease in Al content when the Al content is below 2.0 at.%; as for those annealed at 793 K for 1 h and at 813 K for 0.5 h, an overall increase in real permeability can be obtained compared to those annealed at 793 K for 0.5 h. The permeability under different field amplitudes is also studied and it is found that the relaxation frequency in the lower frequency region tends to moving toward a higher frequency with an increase in field amplitude. All these might be because of the role of Nb in the annealing process and the solubility of Al in the amorphous matrix and nanocrystallized crystallites. | LIU Haishun DU Youwei MIAO Xiexing HAN Kui SHEN Xiaopeng BU Wankui | 2008 | Rare Metals2008，27，5： | 0 |
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