Fractal analysis of polyethylene catalysts surface morphologies based on wavelet transform modulus maxima method

Surface morphologies of supported polyethylene (PE) catalysts are investigated by an approach combining fractal with wavelet. The multiscale edge (detail) pictures of catalyst surface are extracted by wavelet transform modulus maxima (WTMM) method. And, the distribution of edge points on the edge image at every scale is studied with fractal and multifractal method. Furthermore, the singularity intensity distribution of edge points in the PE catalyst is analyzed by multifractal spectrum based on WTMM. The results reveal that the fractal dimension values and multifractal spectrums of edge images at small scales have a good relation with the activity and surface morphology of PE catalyst. Meanwhile the catalyst exhibiting the higher activity shows the wider singular strength span of multifractal spectrum based on WTMM, as well as the more edge points with the higher singular intensity. The research on catalyst surface morphology with hybrid fractal and wavelet method exerts the superiorities of wavelet and fractal theories and offers a thought for studying solid surfaces morphologies. Supported by the Chinese Petroleum & Chemical Corporation Development Department (Grant No. x504024)     

复合掺杂氧化物La0.5Sr0.5CoO2.91的性能和稳定性

采用固相反应法和柠檬酸-硝酸盐溶胶-凝胶低温自蔓延燃烧法（简称柠檬酸法）合成了La0.5Sr0.5CoO2．91（LSC）复合氧化物。借助XRD和SEM对不同制备方法合成粉体的晶体结构和晶粒形貌进行了研究。结果表明：固相反应法可制得均一钙钛矿结构的LSC氧化物，柠檬酸法除制得LSC氧化物外，还有LaSrCoO4相的生成。柠檬酸-硝酸盐溶胶-凝胶低温自蔓延燃烧法合成粉体的粒度相对较小。为研究以Ce0．9Gd0.1O1．95（GDC）为电解质的固体氧化物燃料电池阴极材料的性能，将LSC粉体与GDC粉体按6：4（质量比）制备了固体氧化物燃料电池（SOFC）的阴极片。在空气气氛下使用直流四探针法研究了烧结样品300～800℃的电导率，发现由柠檬酸法得到粉体制备的阴极片的电导率值较高。将制备的样品置于马弗炉中800℃条件下烧结800h，比较失效前后电导率的变化情况，并借助XRD，SEM等测试手段分析样品电导率变化的原因。分析发现，失效后两种样品的电导率值都有所降低，且样品中都有新相生成，晶体形貌有较大的变化。     

柠檬酸在D354树脂上的动态交换过程

在３５℃下，实验测定了柠檬酸溶液在Ｄ３５４树脂固定床离子交换柱中的穿透曲线，研究了进口浓度、进口流速及柱高对穿透曲线的影响。用简单线性推动力模型描述固定床动态过程，考察了轴向返混对穿透曲线的影响，并从穿透曲线回归得到总传质系数，模型计算值与实验数据符合良好。同时还研究了用强酸顶替法洗脱柠檬酸。     

流化床燃烧过程中水煤浆硫分析出规律的研究

燃烧脱硫县有投资省、设备简单、脱硫剂价廉易得等优点,尤以流化床燃烧技术最能适应燃烧过程中添加石灰石或其它脱硫剂来实现脱硫。与流化床燃烧过程中煤的脱硫研究相比,对水煤浆的硫分析出规律的研究甚少。因此,本文作者用改进的ZCL自动测硫仪进行了不同流化床燃烧条件及不同煤浆中硫分析出规律的研究,并讨论了各因素对硫分析出规律的影响。