硅烷化处理对moohzsm5催化剂上甲烷脱氢芳构化活性的影响

结合催化剂的活性评价及固体高分辨核磁共振谱、X射线光电子能谱和X射线荧光光谱和热重等技术,考察了硅烷化处理对Mo/HZSM-5催化剂上甲烷脱氢芳构化活性的影响.结果表明,采用大分子有机硅烷对HZSM-5分子筛进行硅烷化处理,除去了分子筛外表面的酸性位,并使分子筛本身发生了脱铝.硅烷化处理使Mo/HZSM-5催化剂在进行甲烷脱氢芳构化反应时催化剂上总的积碳量明显减少,从而提高了催化剂的活性

飞秒荧光亏蚀光谱技术研究液相体取向弛豫

溶液中分子的快速弛豫过程直接反映了溶液中溶质和周围溶剂分子间的相互作用~1-3．在液相体系中分子取向通常是随机分布的．当溶质分子被线偏振光激发至激发态时，其分子取向将由原来各向同性的球形分布瞬间变成各向异性的椭球分布。由于溶质分子周围大量溶剂分子的存在，通过二者之间相互作用，激发态溶质分子在一定方向上的取向优势将很快弛豫掉。这种溶液中的取向弛豫过程通常是几个到几百皮秒~1-3

Contact transition and force tracking control with joint acceleration feedback damping

Joint acceleration feedback control of high bandwidth is employed to damp oscillations during both the contact transition and force tracking phase. In this control scheme, a classical integral force controller is refined by means of joint acceleration and velocity feedback. This is intended to achieve a stable contact transition without need for adjusting the controller parameters adaptive to the unknown or changing environments, and also to stabilize the force tracking control in the presence of abrupt disturbances during the post-contact phase. Extensive experiments are conducted on the third joint of a three-link direct-drive robot to verify the proposed scheme for various stiffness of the contacted environments, including elastic (sponge) less elastic (cardboard) and hard (steel plate) surfaces. Results are compared with experimental ones by transition control without acceleration feedback