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目前程潮铁矿已回采至-447m水平,-465m水平采准工作也趋于尾声,根据勘探资料,-500m中段及以上水平保有期限已严重不足,因此提出了-500中段以下深部接续工程,通过方案及经济技术指标的对比,确定最优采矿方法,即采用由上而下的开采顺序,先开采-570m中段,-570m中段采用无底柱分段崩落法开采完毕后,再开采-675m中段。-675m中段保安矿柱外矿体采用无底柱分段崩落法回采完毕后,根据生产实际情况,采用上向分层充填法对-675m中段保安矿柱进行回收。-500 m中段以下深部接续工程保证了矿山的可持续发展,解决了采掘失衡的矛盾,而且还创造了可观的经济效益。 相似文献
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Effects of heat treatments on microstructure and mechanical properties of Mg-15Gd-5Y-0.5Zr alloy 总被引:1,自引:0,他引:1
Microstructure and mechanical properties of Mg-15wt.%Gd-5 wt.%Y-0.5wt.% Zr alloy were investigated in a series of conditions. The eutectic was dissolved into the matrix and there was no evident grain growth after solntionized at 525 ℃ for 12 h. The evolution of the phase constituents from as-cast to cast-T4 was as follows: α-Mg solid solution+Mg5(Gd,Y) entectic compound→α-Mg solid solution+ spheroidized Mg5(Gd, Y) phase→α-Mg supersaturated solid solution+cuboid-shaped compound (Mg2Y3Gd2). And the precipitation sequences of Mg-15Gd-5Y-0.5Zr alloy were observed, according to the hardness response to isothermal ageing at 225-300 ℃ for 0-128 h. 相似文献
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电力电子负载(Power Electronic Load,PEL)逐渐代替传统的能耗型负载对电源进行出厂测试.为满足直流电源测试的需要,研制了一种能馈型直流电力电子负载.该电力电子负载采用两级结构,前级为负载模拟部分,后级为能量回馈部分.首先建立负载模拟部分的小信号模型,推导输入电流对占空比的传递函数,设计出合适的PID控制器,最后搭建基于MATLAB的仿真模型进行验证,仿真结果表明所建立的小信号模型是合理的,设计出的PID控制器能使该电力电子负载稳定工作,动态响应较快. 相似文献
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