采空区联络巷密闭气室围岩稳定性研究

针对密闭墙变形开裂造成采空区密闭气室漏气问题,以神东某矿采空区密闭气室为研究对象,建立了密闭墙受力力学结构模型,计算了密闭墙支护阻力,根据低应力区范围确定了密闭墙的位置,得到:支护阻力设计不合理和密闭墙位置选取不合适致使密闭墙变形开裂,造成了密闭气室漏气;2个密闭墙支护阻力达到16 157 kN才能保持良好密闭效果,最终确定密闭墙1支护阻力为12 118 kN,密闭墙2支护阻力为4 039 kN;侧向支承压力的低应力区范围是距离采空区煤壁8～13 m,密闭墙2选择距离采空区煤壁8 m处建造,密闭墙1相距密闭墙2大约6 m。     

A type of inverter power supply based on harmonic elimination PWM control

In order to output sine wave with small degree of distortion and improve stability,a type of inverter power supply is designed based on harmonic elimination pulse-width modulation(PWM)control.The rectifier and filter are added to input circuit of the inverter.Single-phrase full-bridge inverter performs the function of converting direct current into alternating current(DC/AC).In the control circuit,single chip micyoco(SCM)AT89C2051 is used for main control chip to accomplish the hardware design of the control system.A given value of output frequency of the inverter is input in the way of coding.According to the output frequency code which is read,SCM AT89C2051 defined harmonic elimination PWM control data which will be selected.Through internal timing control,the switches are switched under this provision of PWM control data.Then the driving signals of the switches in the inverter are output from I/O of SCM AT89C2051 to realize harmonic elimination PWM control.The results show that adding Newton homotopic algorithm of harmonic elimination PWM control to corresponding software of the control system can make the quality of output voltage of the inverter higher and it will have broad application prospects.     

基于时间序列分解的工作面瓦斯涌出分析方法研究

以回采工作面推进过程中落煤瓦斯涌出和采空区瓦斯涌出为研究对象,利用2种瓦斯涌出特征的特点,提出了1种瓦斯涌出量时间序列分解的方法。对采空区瓦斯涌出特征、落煤瓦斯涌出特征和工作面平均瓦斯涌出特征变化趋势进行了分析,认为3种瓦斯涌出特征变化既有相关性又有独立性,基于时间序列分解的方法将采空区瓦斯涌出和落煤瓦斯涌出的特征分别提取出来并进行了趋势分析。以山西某工作面连续15 d瓦斯涌出数据为例,对瓦斯涌出量时间序列分解、特征提取和分析方法进行了验证,认为该分析方法有效可行。     

烟雾发生器的研究与设计

位于平曲线上的桥梁,当平曲线半径较小时,其受力和变形特点与直线桥梁有较大差别。对影响曲线桥梁梁体偏位的多种因素进行了定量分析,并提出了相关建议。