Reactivity and codeposition of Co3O4 powderswith nickel in a Watts bath

The effect of the physico-chemical characteristics of Co3O4 powders on their reactivity in solution and their incorporation in a nickel matrix has been investigated in a Watts nickel plating bath. The results showed that the surface area of the powder present in suspension not only catalyses the adsorption or desorption phenomena occurring at the particle/solution interface but also has a significant effect on the incorporation of the particles into the nickel matrix. It has been found that the use of Co3O4 with high specific surface area (40m2g–1) significantly limits the growth rate of the electrodeposited composite coatings. Furthermore, it has been shown that the codeposition of these more reactive particles leads to significant changes in the microstructure and texture of the nickel matrix. Finally, it has been found that, according to their specific surface areas, the amount of H+, Ni2+ and Ni[B(OH)4]+ ions adsorbed on the Co3O4 oxide surfaces and the quantities of particles codeposited can vary considerably.     

周期性热湿作用下多孔吸湿体吸解湿性能的实验研究

选择硅胶作为多孔吸湿体.在夏季气候的周期性热湿作用下,测试了硅胶粒径和厚度对其自然吸解湿性能的影响.表明粒径对自然吸解湿性能有一定影响;硅胶的吸解湿性仅在浅表层中进行,这对于利用多孔吸湿体改善热湿环境有一定的指导意义.     

CH4/CO2不同浓度混合气体的吸附－解吸实验

选择山东菜园矿的气煤和山西古交矿的焦煤的平衡水煤样对不同浓度的CH₄和CO₂混合气体进行了吸附－解吸实验,分析了CH₄和CO₂在吸附－解吸过程中各组分浓度的变化规律,并探讨分析了实验过程中出现高压阶段吸附量小于低压时的原因.结果表明,不同浓度的CH₄和CO₂混合气体的解吸曲线都滞后于吸附曲线;相同条件下,焦煤的吸附量大于气煤的吸附量;CO₂与CH₄浓度之比越大,气体的吸附量越大;吸附过程中,CO₂组分的吸附速率是先快后慢,而CH₄组分的吸附速率先慢后快,解吸时则相反.吸附和解吸平衡时,游离相中的CO₂浓度低于原始混合气体中的CO₂浓度,CH₄浓度高于原始气体中CH₄浓度.实验结果证实了CO₂在与CH₄的竞争吸附中占据优势,注入CO₂可以有效地置换或驱替煤层CH₄,注入CO₂气体的数量越大、相对浓度越高,单位压差CH₄解吸率和CO₂吸附率就越高.     

主动测压法测定煤层瓦斯压力中补偿气体的选择

为选择合适的气体作为主动测压法测定钻孔煤层瓦斯压力中的补偿气体,从煤对CH4、CO2和N2的吸附性研究入手,证实了煤层对CH4和N2的吸附-解吸是可逆的,而对CO2的吸附解吸是不可逆的,并分析了CO2作为补偿气体对CH4的吸附-解吸平衡产生的影响,最终提出了N2更适合作为补偿气体。通过现场实践表明：CO2作为补偿气体测得的瓦斯压力存在一定的误差,误差可达0.05～0.20 MPa,而N2作为补偿气体时误差较小,能够较准确测得煤层原始瓦斯压力。     

基于红外测温的煤体瓦斯吸附-解吸过程温度变化特征研究

应用红外测温摄录仪分别对不同压力、不同变质条件下的煤体瓦斯吸附-解吸过程中温度变化进行测量,将红外数据进行小波滤噪后拟合出瓦斯吸附-解吸特征函数曲线。分析得出结论:不同平衡压力下吸附过程中升温趋势符合指数函数关系,解吸过程中降温趋势符合对数函数关系;煤体变质程度也会影响吸附-解吸过程中温度变化特征,煤体变质程度越大,吸附-解吸造成的温度变化幅度越大。拟合函数△T=K(1-et/b)参数K表征了吸附-解吸所引起的煤体温度变化最大值,温度变化最大值与煤体瓦斯解吸量成线性正相关。