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In order to reveal the mechanism of surrounding rock deformation and instability of soft rock roadway in 12# working face of Puhe coal mine, and synthetical analysis of the surrounding rock, deformation and failure of the roadway shows that the original support scheme is difficult to maintain the stability of roadway. Thus the basic concept of roadway surrounding rock control: Single anchor bolt form a compression zone to control the failure and expansion of surrounding rock, and a comparable number of anchor bolts form a homogeneous compression zone to inhibit the development of surrounding rock plastic zone. The “anchor blot + anchor cable net + concrete shotcrete support plan (arrangement of anchor cables four to five)” is proposed. Furthermore, and FLAC3d numerical simulation software was used to verify the rationality and reliability of the supporting scheme of “bolt + anchor cable net + concrete shotcrete support scheme (four to five anchor cables)” support scheme. The on-site monitoring results show that the soft rock roadway in Puhe Coal Mine 12# working face return airway passes through the “bolt + anchor cable net + concrete shotcrete support scheme (anchor cable four to five arrangement)” to reduce the surrounding rock deformation and become stable. The sinking amount of the roof and floor in the roadway is 251.2 mm, the convergence amount of the two sides in the roadway is 231 mm, supporting system and surrounding rock form the stable compression zone, the soft rock roadway can be effectively controlled by the support scheme, which can provide reference value for other similar engineering.

Cooccurrence relation extraction of abundant tags is very significant f or information retrieve and tag recommendation. This paper presents a parallel extraction method of tag cooccurrence relatio n based on cloud computing. At last, two experiments show that the parallel extraction method can improve the performance of retrievals greatly and have good scalability. The research may play a role in the facilitative effect on the expanding application of social tagging s ystem with abundant, multiplex, complex annotated data.

Optimizing the NACA0015 airfoil which is widely applied in small-scale vertical axis wind turbine to make it has a better aerodynamic performance. In the optimization process, using CST parameterization method to perturb the airfoil geometry, the thickness and camber of the airfoil are selected as the constraint, and the value of the maximum tangential force coefficient is chosen as the objective function, the genetic algorithm based on non-dominated sorting (NSGA-II)is selected as an optimization method, calculates the aerodynamic performance of the airfoil by applying the approach of combining XFOIL program and Viterna-Corrigan post-stall mode ,and establishes the optimizing process by the optimization software modefrontier for NACA0015 airfoil’s muti-point optimization, validate the airfoil’s performance with CFD finally. The result illustrates that, by comparing with the NACA0015 airfoil, the optimized airfoil’s lift to drag ratio is improved over a wide range of attack angles, the stall performance is more gentle. The maximum lift coefficient, the maximum lift-drag ratio and the maximum tangential force coefficient are increased by 7.5%,9 and 8.87%, respectively. The optimized airfoil has a wide variable condition performance, more suitable for the operating conditions of a vertical axis wind turbine. Finally, predict the rotor efficiency with optimized airfoil and NACA0015 airfoil for different tip speed ratios and different solidities with multiple streamtube model, the result shows the rotor with optimized airfoil has a higher efficiency. Keyword: vertical axis wind turbine; CST parameterization; NSGA-II; airfoil; optimization; multiple streamtube model

By turning to the theory of elastic thin plates, a mechanical model of the main roof breaking for severely inclined seam under long wall working was esbalished, in which formulaes were deduced for the calculation of the stress distribution. When the main roof stress distribution was characterized, the failure form of the roof in the long wall coal seam under work was given with the failure criterion deduced. The deduced failure criterion was then applied to the No.3232(3) face of the Lizuizi Coal Mine; the first pressure for the working face was accurately predicted. Results of the field application show that the main roof of the severely inclined coal seam under long wall working breaks in the O-X pattern, which is basically in accordance with the reality.

According to the geological and mining technical conditions of No.18128 sublevel caving face with suspend-shift support, the first working face of the working area, the distribution laws of abutment pressure were studied by jointly employing FlAC3D numerical simulations and field tests. With the full consideration of these laws and the service timelimit of the mining district, the optimal location of the terminal mining line, should be 60 m away from the W4-B8 track dip, which was 20 m shorter than the 80 m distance determined according to traditional experiences. The retained coal safety pillar for the protecting of dips, already proved by the industrial practice, can not only improve the rate of coal recovery and satisfy the subsequent service requirement for the following working faces, but also decrease the maintaining expenditure and thus increase profits.