<正>分析了风振条件下大跨度屋盖结构中悬挑竖向位移的控制方法，指出传统的模态应变能法因忽略阻尼器的耗能刚度部分可能产生较大误差，并对此给出了修正方法。推导了附加消能支撑的竖向控制力、等效刚度和等效耗能因子公式。根据上述方法和公式，对一大悬挑屋盖结构进行了风振控制设计。经实例应用说明，笔者提出的风振控制设计方法方便实用。

The pollen viability of five species of Catalp, (Catalpa bungei, C. fargesiif, duclouxii, C. ovata, C. fargesii aud C. speciosa) were studied by germinative method on agar plate. The result indicated that the optimal pollen germinatiou eavironment was 25℃ and 611. The optimal germinative mediums scheme was 10% sucrose, 0.01% boric acid and 1% agar. At the condition of water planting and the room temperature, the rate of germination of pollen was the highest during the first day to the third day. It decreased significantly from the forth day to the end of a week. The rate of pollen germination was the highest and kept stable highest level in cryopreservation and-70℃. It was higher than tha! in-20℃ and 0℃. It was the lowest at the room temperature. After storage in liquid nitrogen, thawing treatment at varied temperate of 35--38℃ for 5rain could greatly increase the viability of pollen.