Fetr6 is an underground mine using the stope-and-pillar mining method. As there was some evidence regarding pillar failure in this mine, improving works such as roof support and replacing existing pillars with concret...Fetr6 is an underground mine using the stope-and-pillar mining method. As there was some evidence regarding pillar failure in this mine, improving works such as roof support and replacing existing pillars with concrete pillars (CP) were carried out. During the construction of the second CP, in the space between the remaining pillars, one of the pillars failed leading to the progressive failure of other pillars until 4 000 m 2 of mine had collapsed within a few minutes. In this work, this phenomenon is described by applying both numerical and empirical methods and the respective results are compared. The results of numerical modelling are found to be closer to the actual condition than those of the empirical method. Also, a width-to-height (W/H) ratio less than 1, an inadequate support system and the absence of a detailed program for pillar recovery are shown to be the most important causes of the Domino failure in this mine.展开更多
Using Technology Computer-Aided Design(TCAD) 3-D simulation,the single event effect(SEE) of 25 nm raised source-drain FinFET is studied.Based on the calibrated 3-D models by process simulation,it is found that the amo...Using Technology Computer-Aided Design(TCAD) 3-D simulation,the single event effect(SEE) of 25 nm raised source-drain FinFET is studied.Based on the calibrated 3-D models by process simulation,it is found that the amount of charge collected increases linearly as the linear energy transfer(LET) increases for both n-type and p-type FinFET hits,but the single event transient(SET) pulse width is not linear with the incidence LET and the increasing rate will gradually reduce as the LET increases.The impacts of wafer thickness on the charge collection are also analyzed,and it is shown that a larger thickness can bring about stronger charge collection.Thus reducing the wafer thickness could mitigate the SET effect for FinFET technology.展开更多
Through-flow method is still widely applied in the revolution of the design of a turbomachinery, which can provide not merely the performance characteristic but also the flow field. In this study,a program based on th...Through-flow method is still widely applied in the revolution of the design of a turbomachinery, which can provide not merely the performance characteristic but also the flow field. In this study,a program based on the through-flow method was proposed, which had been verified by many other numerical examples. So as to improve the accuracy of the calculation, abundant loss and deviation models dependent on the real geometry of engine were put into use,such as: viscous losses,overflow in gaps, leakage from a flow path through seals. By means of this program, the aerodynamic performance of a certain high through-flow commercial fan/booster was investigated. On account of the radial distributions of the relevant parameters, flow deterioration in this machine was speculated. To confirm this surmise, 3-D numerical simulation was carried out with the help of the NUMECA software. Through detailed analysis, the speculation above was demonstrated, which provide sufficient evidence for the conclusion that the through-flow method is an essential and effective method for the performance prediction of the fan/booster.展开更多
文摘Fetr6 is an underground mine using the stope-and-pillar mining method. As there was some evidence regarding pillar failure in this mine, improving works such as roof support and replacing existing pillars with concrete pillars (CP) were carried out. During the construction of the second CP, in the space between the remaining pillars, one of the pillars failed leading to the progressive failure of other pillars until 4 000 m 2 of mine had collapsed within a few minutes. In this work, this phenomenon is described by applying both numerical and empirical methods and the respective results are compared. The results of numerical modelling are found to be closer to the actual condition than those of the empirical method. Also, a width-to-height (W/H) ratio less than 1, an inadequate support system and the absence of a detailed program for pillar recovery are shown to be the most important causes of the Domino failure in this mine.
基金supported by the National Natural Science Foundation of China (Grant Nos. 60836004,61006070,and 61076025)
文摘Using Technology Computer-Aided Design(TCAD) 3-D simulation,the single event effect(SEE) of 25 nm raised source-drain FinFET is studied.Based on the calibrated 3-D models by process simulation,it is found that the amount of charge collected increases linearly as the linear energy transfer(LET) increases for both n-type and p-type FinFET hits,but the single event transient(SET) pulse width is not linear with the incidence LET and the increasing rate will gradually reduce as the LET increases.The impacts of wafer thickness on the charge collection are also analyzed,and it is shown that a larger thickness can bring about stronger charge collection.Thus reducing the wafer thickness could mitigate the SET effect for FinFET technology.
基金supported by National Natural Science Foundation of China(51236001)National Basic Research Program of China(2012CB720201)Beijing Natural Science Foundation(No.3151002)
文摘Through-flow method is still widely applied in the revolution of the design of a turbomachinery, which can provide not merely the performance characteristic but also the flow field. In this study,a program based on the through-flow method was proposed, which had been verified by many other numerical examples. So as to improve the accuracy of the calculation, abundant loss and deviation models dependent on the real geometry of engine were put into use,such as: viscous losses,overflow in gaps, leakage from a flow path through seals. By means of this program, the aerodynamic performance of a certain high through-flow commercial fan/booster was investigated. On account of the radial distributions of the relevant parameters, flow deterioration in this machine was speculated. To confirm this surmise, 3-D numerical simulation was carried out with the help of the NUMECA software. Through detailed analysis, the speculation above was demonstrated, which provide sufficient evidence for the conclusion that the through-flow method is an essential and effective method for the performance prediction of the fan/booster.
