Abstract: Interaction between coal face hydraulic support and floor is the crucial point for surrounding rock control in coal face and hydraulic support design optimization. Based on the principle of floor specific pressure testing, mechanized coal face hydraulic support parameters are tracked and such mechanical parameters as allowable specific pressure of floor strata are measured, in accordance with which this paper studies on the surrounding rock control in coal face and hydraulic support selection in fully mechanized coal face.
Abstract: In order to grasp the movement rules of three soft coal caving complex working plane strata and stoping space surrounding rock and hydraulic support interactions relationship, improve the management of mining roof, to do research about the distribution rule of caused abutment pressure and shield support of initial supporting force, the work resistance and adaptability of coal seam. The first coalface of testing mine 1301 mining coal gangue is clip three soft and thick coal seam mining, adopt fully mechanized caving technology, choose ZF6400/17/32 type support screen type top coal caving hydraulic to support working face roof support, in order to provide better services for safe production in the working face, especially study on related factors affecting the observational of working mine pressure.
Abstract: It is significance to predict coal production for balancing coal supply and demand in China. The primary goal of this research is the prediction of coal production in china. The method used in the study is known as the BP neural network. The BP neural network is designed with the MATLAB simulation software based on coal production historical data from 1980 to 2007. The studies we have performed showed that the prediction of coal production based on BP neural network is reasonable and valuable. Finally, we get the prediction of coal production from 2010 to 2015, and the prediction indicates that the coal production will increase in the next 5 years.
Abstract: The electronic structures and magnetic properties of the compound Co(endi)2(N3)2 are studied by means of the first-principles method. According to the calculations, there is ferromagnetic interaction in the compound, and the magnetic coupling comes from the spin delocalization effect from Co2+ to the azide ligand. It is found that there is strong intralayer and weak interlayer magnetic couplings in the compound. It also reveals semi-metallically magnetic properties.
Abstract: This paper presents a three-dimensional nonlinear finite elemental analysis about the reinforcement concrete beams strengthened by bolting steel plate, which is a new strengthening method by anchoring plate to beam surface but not using any glue to help bonding. The contact effects between the steel plate with reinforced concrete beam surface was simulated by developing the contact elements. The effects of the plate thickness and the collocation of anchor bolts were investigated. The damage evolution about variable collocation of anchor bolts were investigated. It is declared that the collocation of anchor bolts play an obvious effects on the flexural capacity of strengthened beams, but the plate thickness give a little influence on it.
Abstract: For the pores edge detecting of the Activated Carbon Fibers (ACF) material images, traditional approaches are difficult to obtain the complete edge information. Snake algorithm is a reasonable approach for edge detection. An improved initial contour Snake model is proposed in this paper. A rectangle is first located to surround the edge to be detected instead of drawing a series of points as initial contour. Then, we map these points on the rectangle to the edge surrounded according to certain rule to constitute the initial contour. After the mapping strategy, Snake algorithm is used to iterate the initial contour. Experiments show that complete pores edge information are achieved. Based on the edge pixels, the area of each pores can be calculated easily.
Abstract: In order to research the static properties of FRP composite laminates with central hole, the numerical simulation and experimental method are used. The simulation is achieved by the finite element analysis tool with the progressive damage method. During the simulation, the Hashion failure criteria and the selective completed material degradation models are adopted. Proper specimens of FRP composite laminates with central hole are prepared and the static tests are carried out. The results indicate that progressive damage method can simulate the failure process of FRP laminates with central hole and the simulative results agree well with the experimental data.
Abstract: A novel curable liquid polysilane (CLS) containing reactive unsaturated bond and Si-H was synthesized from dichloromethylvinylsilae, methyldichlorosilae and Na in presence of 18-crown-6 under sonication at relatively lower temperature and its structure was characterized by FT-IR, 1H-NMR. The cure behavior of CLS was investigated by DSC,FTIR. Thermal stability of cured CLS was examined by TGA. The results showed that the cured polysilane exhibits good anti-oxidation performance under high temperature. And the sinted CLS exhibited high temperature resistance and good ceramic formability.
Abstract: The influence of temperatures and passes on hot extruded 7075 Al bar were investigated using hydraulic press. The microstructures were observed using optical microscopy. The results showed that the as received AL bar consists of lamellar grain structures, and that equiaxed mixed grain size were observed with different passes at 320°C. Continuous dynamic recrystallization (CDRX) is responsible for the formation of small grain. The large grain tends to increases with more passes due to longer holding time. CDRX were observed for one pass only at 480°C. Lamellar grain structures were formed with different passes at 480°C.The lamellar grain structures are aligned at 50° to 70° to compression direction from one pass to four passes.
Abstract: The preforms were woven by the co-yarns which were consisted of GF, PP and PET. Then the co-yarns were manufactured into hybrid thermoplastic composites. The parameters of the forming process were studied by analyzing the tensile properties of the composites. The results show that the composite holds the best tensile properties when the pressure is 5MPa, the packing temperature is 190°C, and the holding time is 30 min. The existing of a second pressure of 10 MPa at 150°C for 3 min will help to improve the capacity of the load supporting for the GF/PET thermoplastic composites