带软启动器回路输煤皮带启动跳闸原因分析

液力偶合器和软启动器在机械传动系统中是具有提高电机启动能力、减小冲击与振动的传动装置.但是这两种装置同时用于一个机械传动系统时情况就发生了变化,造成启动失败.文章对带软启动器回路输煤皮带启动失败的原因进行了分析.文章认为,启动失败的原因是软启动器为降压启动,初始转矩小,使液力偶合器的传递功率增加缓慢,致使皮带难以启动,启动时间过长便导致电源开关保护跳闸,启动失败.文中提出了解决方案,如取消软启动器或增加液力偶合器的充油量等.     

Texting While Driving: An Empirical Investigation of Students’ Attitudes and Behaviors

The distracting effects of texting while driving activity of young adults are receiving increasing attention. The findings indicate that individuals involved in texting while driving also engage in other risky behaviors. Furthermore, frequency of texting while driving appears to be related to several factors, including self-control, attitudes toward texting and responsible driving, and opinions of peers, but interestingly not with social responsibility. In conclusion, the frequency of texting while driving of young adults appears to be related to several factors, suggesting possible ways the frequency of texting while driving may be affected.     

Effect of pressure on elemental diffusion in sulfur–iron reaction

The reaction between sulfur and iron under high pressure and high temperature (HPHT) was studied. Sulfur–iron reaction models under different pressure levels were constructed. The morphology and formation mechanism of the reactants were comprehensively analyzed by scanning electron microscopy, energy-dispersive spectroscopy–line scanning, metallographic microscopy, and Raman spectroscopy. The results indicated that the pressure of the reaction could significantly affect the diffusion behavior of sulfur and iron during the reaction. With an increase in pressure, the diffusion of iron in the system was inhibited, whereas that of sulfur was enhanced. The pressure distribution gradient at the reaction interface was simulated by finite element calculation. The effect of pressure gradient as the driving force of the reaction on the diffusion behavior of elements was evaluated by thermodynamics combined with experimental results. Based on the experimental results, finite element simulation, and formula derivation, a new standpoint was proposed: the diffusion of substances in the HPHT system was affected by the pressure gradient at the interface.     

沿空掘巷窄煤柱合理宽度研究

为了减少干河煤矿区段煤柱的宽度,通过理论分析和FLAC3D软件建立2-1052巷留窄煤柱沿空掘巷数值模型,确定2-1052巷沿空掘巷所留设窄煤柱的宽度为6m.现场窄煤柱护巷掘进后,巷道两帮的深部位移量控制在有效范围内,可以保证巷道的安全掘进及正常回采.     

干河煤矿松软破碎半煤岩巷支护技术优化研究

为解决干河煤矿三采区辅助运输巷掘进初期巷道持续变形的问题,通过围岩位移监测、数值模拟等方法,依据具体的地质条件建立相应的数值模型.从锚杆锚索参数、底板支护等几个方面进行支护方案优化,设计采用锚网索喷+反底拱联合支护技术.结果表明,新方案掘进期间巷道围岩成巷后快速稳定,取得了良好的支护效果.     

大功率有源电力滤波器驱动电路的设计

有源电力滤波器的主电路为由IGBT构成的逆变器结构,尤其是对大功率的有源电力滤波器,其主电路IGBT的可靠驱动以及故障检测是保证有源电力滤波器稳定运行的关键所在。因此针对100 k V·A的有源电力滤波器驱动电路进行设计,光纤接口电路实现了强弱电之间的隔离;并以2SD315AI作为核心驱动模块,据此设计了相关的外围电路,并针对驱动的关键问题进行了探讨分析,成功设计了驱动电路。经实际测试,对IGBT驱动特性良好,应用于有源电力滤波器,实现了对谐波电流的补偿。