On the oxidative coupling of methane with carbon dioxide over CeO2/ZnO nanocatalysts

The nano-CeO₂/ZnO catalysts were prepared using a novel combination of homogeneous precipitation with micro-emulsion for oxidative coupling of methane with CO₂ as an oxidant. The prepared catalysts were compared with those prepared using the conventional impregnation. The catalysts prepared in two ways were characterized with FTIR, TEM, XRD and CO₂-TPD. The effects of the reaction temperature, the amount of ZnO doped in the catalysts and the average size were investigated. The experimental investigation demonstrated that methane conversion over the nano-CeO₂/ZnO catalysts prepared by the combined technique was higher than that obtained over catalysts prepared by the conventional impregnation. A better low-temperature activity has also been achieved over the nanocatalysts. There was no clear trend between the average size of nano-CeO₂/ZnO catalysts and their catalytic performance but methane conversion increased with increasing fractal dimension of nanocatalysts.     

超重力反应结晶法纳米碳酸钙浆料及粉料的表面处理

研究了脂肪酸盐A、水溶性铁酸酯偶联剂B（B1)以及铁酸酯偶联剂C对新型超重力反应结晶法所得的纳米CaCO3浆料及粉料的湿法表面处理的配方与工艺，确定了A体系的最佳改性时间为30～40min、改性温度为40～50℃、改性剂用量(质量分数)为3%～5％；B(B1)体系搅拌强度必须很高，改性时间30～40min，改性温度80℃左右，改性剂用量(质量分数)3％～5％；C体系的最佳改性时间为30～40min，改性剂用量(质量分数)为3％～5％。同时，采用红外光谱对改性前后的纳米碳酸钙进行了表征，表明改性刑已连接至CaCO3表面。最后，用分散稳定模型简要分析了改性机理。     

4-硝基-4′-N,N-二(2-羟丙基)氨基偶氮苯的合成与表征

以苯胺、环氧丙烷为原料制备了N,N 二(2 羟丙基)苯胺(NHPPA),然后NHPPA与对硝基苯胺通过重氮偶合反应制备了一种具有推拉电子结构的偶氮化合物4 硝基 4′ N,N 二(2 羟丙基)氨基偶氮苯(NHPA)。用元素分析、核磁共振、红外光谱分析了NHPA的结构,用紫外可见光谱研究了NHPA的吸收特性,在260和400nm附近发现特征吸收峰。并探讨了反应时间以及苯胺与环氧丙烷的量比对N,N 二(2 羟丙基)苯胺产率的影响,发现适宜的反应条件为:n(苯胺)∶n(环氧丙烷)=1 0∶2 3,反应时间为4h,相对于苯胺的产率可达92%。     

阳离子型偶联表面活性剂改性硝酸铵性能研究

对阳离子型偶联表面活性剂膨化处理的改性硝酸铵进行了电镜扫描、孔径与孔容分布、粒径分布、比表面积、抗吸湿结块性及爆炸性能的实验研究，结果表明：同普通硝酸铵相比，阳离子型偶联改性硝酸铵的晶形不规则，富含气孔；比表面积大，可达3869．56cm^2／g；95％有效孔径处于介孔范围，有较小的粒径范围，主要分布在10～1000μm范围内；并且有良好的抗吸湿结块性，改性硝酸铵的吸湿率比普通硝酸铵的吸湿率降低约60％，抗压破坏力仅为普通硝酸铵的1／6，用其制得的粉状工业炸药具有更好的物理性能和爆炸性能。     

增强聚氨酯硬泡塑料的冲击性能研究

本文研究了SiO2和纤维增强剂对于聚氨酯硬泡塑料冲击性能的增强效应.试验结果表明,加入SiO2并不能增强聚氨酯硬泡塑料冲击性能.然而以2.5% KH550偶联剂四氢呋喃溶液处理的玻璃纤维作为增强剂,能使聚氨酯硬泡塑料的冲击性能有显著的提高.     

智能电动车辆横纵向协调与重构控制

针对具有高度非线性、强耦合和冗余特性的智能电动车辆运动控制问题,提出了一种由协调控制律和控制分配律组成的横纵向综合控制新方法.首先,建立准确表征智能电动车辆行为机理的动力学模型;其次,采用非奇异滑模控制技术,引入非线性滑动模态切换面,设计有效克服非线性及不确定特性的协调控制律,保证系统状态在有限时间内收敛至平衡点;在此基础上,考虑到轮胎存在冗余和耦合特性,提出基于内点法的控制分配算法来完成期望广义力/力矩的优化分配,实现轮胎横纵向力的协调与重构.仿真结果表明了该方法的有效性.     

New N,O-containing ligands for the biomimetic copper-catalyzed polymerization of 2,6-dimethylphenol

Poly(2,6-dimethyl-1,4-phenylene ether) (PPE), which is widely used in high-performance engineering plastics, is obtained by the copper-catalyzed oxidative coupling of 2,6-dimethylphenol. The oxidative polymerizations have been carried out in acetonitrile with structurally related [copper-(N,O-containing ligand)] complexes as the catalyst precursor compounds, which appeared to be of great interest for a better understanding of the factors influencing the catalytic activities. Steric effects (influence of a methyl group close to the metal center; ligands 4–7) or electronic effects (imino versus amino group; ligands 4, 5, 8 and 6, 7, 9, respectively) on the polymerization rates have been demonstrated. The use of mono- or dinucleating ligands has strengthened the proposed mechanism of the reaction involving dinuclear active species.     

Oxidative coupling of methane over LaCoO3−δ-based mixed oxides

The catalytic activity of LaCoO_3–-based mixed oxides for the oxidative coupling of methane has been tested by TPR and cyclic reaction. Characterization has been done by XRD, TGA and Mössbauer spectrometry. It is likely that the perovskite-crystal structure containing hypervalent metal ions has an important role and that unique structural oxygen species in the perovskite contribute to the partial oxidation of methane.     

六维腕力传感器非线性正解耦方法设计

多维力传感器利用其多个转换单元完成测量加载于其结构上未知负载的作用效果,解耦是其设计的重要组成部分。针对传统静态线性解耦方法的不足,试图将传统线性解耦方程扩展为多项式结构,受其多元高次方式通解形式的启发,构造了一种多项式非线性静态正解耦方程,该方法无需传统线性解耦方法中的曲线拟合、逆解,不依赖以系统是线性为前提,且方程可以扩展成任意结构的多项式。实验结果表明:该方法能降低输出耦合误差。     

一种螯合型钛酸酯偶联剂的制备

介绍了一种以钛酸四异丙酯、丙烯酸和焦磷酸烷基酯为原料,乳酸为螯合剂合成的钛酸酯偶联剂,它适用于无机粉末有机包覆改性中的粉末预处理。