CPT: Pharmacometrics & Systems Pharmacology, 7: 404–412 (2018). https://doi.org/10.1002/psp4.12301. The published version of this article mis-spelled the last (family) name of one of the co-authors. Bjorn L. Miliard should instead be listed and indexed as Bjorn L. Millard. The published version also omitted the middle initial of one of the co-authors. John Burke should instead be listed and indexed as John M. Burke. The authors apologize for the errors.
Reasonable roadway layout timing can effectively reduce the deformation of the rock surrounding the roadway and relieve mining and excavation tension. To analyze the mine pressure behavior of the gob-side entry at the edge of a goaf and the roof stability along the strike direction in the middle of a goaf, field observations and particle flow discrete element numerical simulation (PFC) method were performed. The results showed that deformation of the surrounding rock mainly occurred because of roof-to-floor convergence, caused mainly by floor heave. The mechanical behaviors of the rock mass, such as elasticity, fracture, and post-peak softening, could be simulated using the model of a jointed rock mass generated by rigid block elements in the PFC method. Considering the length of the violent and reduced roof activity zones and the activity duration as the indices to determine the basic stability of the goaf, the basic stability distance of the tested goaf edge was 135 m after coal seam mining, and the basic stability time was 27 days. The basic stable distance in the middle of the goaf was 183.4 m after coal seam mining, and the basic stability time was 37 days.
Gas control technology traditionally based on the physical properties of gas. However, researches show that making use of microbial technology is another way to deal with coal seam gas, but there is no report about industrial application of it. In this paper, firstly a contrast experiment of microbial reagent and water demonstrates methane can be degraded by microbial technology. Then introduce the microbial reagent preparation, the equipments, design of injecting holes and testing holes, injecting pressure, injecting time, injected volume, measurement of parameters and some other schemes of this industrial test. Test result show that the dynamic phenomenon of gas can be weakened remarkably after injecting the microbial reagent into coal seam; the gas concentration of return air, gas content, gas pressure and index K1 can be reduced in different degree. So the effect of gas control by microbial technology at coal mines is obvious, and large-scale industrial application of it is feasible.
Under laboratory conditions,the effects of several heat treatment cooling modes on hardness,impact toughness,and microstructure of low-alloy wear-resistant steel samples were studied.The results show that different cooling rates have a large impact on the microstructure and properties of the low-alloy steel,the impact toughness of air-cooled samples is better than that of water-cooled and oil-cooled samples,and the hardness of the water-cooled samples is slightly higher than that of the other two groups samples;the optimal hardness and impact toughness were obtained in the samples after 880 ℃ quenching and oil cooling.
The conventional R.C.D snubbers convert the excessive electrical power into heat and emit it, which lower the circuit efficiency and increase the volume of heat sink. So these snubbers cannot be applied in the high performance convert. The passive lossless snubber with passive component inductance, capacitance and diode, without resistant, can feed the excessive power back to the grid. The loss is low. The circuit has high efficiency and reliability. A flyback charger with the passive lossless snubber was introduced, and the passive lossless snubber circuit is experimented. Results prove that the charger has higher efficiency and reliability. The passive lossless snubber can be applied in the high performance converter.
According to the caving and accumulation characteristics of gangue in goaf of a large dip coal seam, a new flexible roadway protection (FRP) technology was put forward. Meanwhile, four types were designed of blocking gangue steel mesh: "1 type", "wave type", "L type " and "L-wave type", to adapt to the characteristics of overlying strata and the impact strength of gangue in the different large dip angles working face. Blocking gangue steel mesh could convert the impact (harmful behavior) of the rolling gangue into the filling force (advantageous behavior) of the roadside support body. Consequently, a roadside support body made of compacted gangue as aggregate was formed. Besides, the calculation formulas for the impact velocity and the maximum impact force at the moment of contact between the gangue and the steel mesh was attained through the mechanical analysis. On this basis, the strength checking method for steel mesh was obtained. The application of FRP technology to engineering practice indicates that this technology has the features of high bearing capacity, strong impact resistance, simple process, low cost, etc. It is suitable for the application of the gob-side entry retaining for medium-thick coal seam with large dip angle. The introduction of FRP technology has significantly expanded the application scope of the gob-side entry retaining technology.
Using software ProCAST,the lost foam casting process from filling mold to solidification of high-manganese steel tooth casting was simulated,the casting defects position during filling mold and solidification were forecasted and analyzed.Based on this,the design of foundry technology of lost foam casting was optimized,and the shrinkage defects in the important position were prevented.
According to the occurring, expending and evolving process of the landslip, which has taken place in J contract segment # 3 slope at Wan-Liang expressway, the mechanisms of landslip under the excavating unloading condition in slow leaning stratum are deeply discussed; and the double face shear effect and joining move effect that lay in stratum rock slope landslip are put forward, which is very suitable to the result of model testing; and therefore a scientific basis for efficient controlling these types of landslips, is provided.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
'/%3e%3cuse xlink:href='%23a' transform='rotate(144 450 300)'/%3e%3cuse xlink:href='%23a' transform='rotate(216 450 300)'/%3e%3cuse xlink:href='%23a' transform='rotate(288 450 300)'/%3e%3c/svg%3e)