Electrochemical profile of nano-particle CoAl double hydroxide/active carbon supercapacitor using KOH electrolyte solution

A nano-structured CoAl double hydroxide with an average particle size of 60–70 nm was prepared by a chemical co-precipitation. It was used as a positive electrode for the asymmetric hybrid supercapacitor in combination with an active carbon negative electrode in KOH electrolyte solution. The electrochemical capacitance performance of this kind of hybrid supercapacitor was investigated by means of cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge tests. A specific capacitance of 77 F g⁻¹ with a specific energy density of 15.5 wh kg⁻¹ was obtained for the hybrid supercapacitor within the voltage range of 0.9–1.5 V. The supercapacitor also exhibits a good cycling performance and keep 90% of initial capacity over 1000 cycles.     

The relationship between the stability of emulsified diesel and flotation of graphite

The emulsified diesel is a good collector of non-metallic minerals, such as coal and graphite, but it suffers from easily stratification which may lead to the change of graphite flotation. This paper reports research on the relationship between the stability of emulsified diesel and graphite flotation. The results shows that the proper Hydrophile Lipophilic Balance (HLB) value (13–14) and co-emulsifier (hexyl alcohol) can improve the stability of emulsified diesel and increase the recovery of graphite. Better dispersion state of diesel in water and smaller oil droplets could be formed when the stability of emulsified increases, which leads to enhancement of graphite recovery. Besides, the tests of the real ore proved that emulsified diesel is better collector than common diesel.     

单一综放开采导水裂缝带形成机制研究

水体下采煤过程中,由于采空区围岩的应力重新分布,将产生变形、位移乃至破坏,若波及到上覆水体,则易发生透水事故,严重威胁矿井安全生产。应用岩石破裂过程分析RFPA2D系统,数值模拟再现了单一综放开采条件下覆岩变形破坏的动态发展过程;通过对模拟结果的分析,得出了导水裂缝带的分布特征、位移分布、应力分布及地表裂缝形成的原因,阐明了覆岩的破坏机理和单一综放开采条件下导水裂缝带的形成机制,揭示了采动影响下覆岩的破坏规律。结果表明,导水裂缝带的形成是一个渐进的过程,开挖造成上覆岩层不同区域拉应力分布的差异是造成导水裂缝带形成的根本原因。