During the climbing phase, the parameters, such as weight, center of weight, altitude and velocity of a trans-aerosphere vehicle changed so much so that its control and stability also change so much. 跨大气层飞行器在爬升过程中重量、重心、高度和速度等参数变化剧烈,因而飞行器的操纵稳定特性也变化急剧,与常规飞行器相比其飞行控制律设计有它的特殊性。
Methods : Each center in clinical trials is regarded as a stratum. Taking the stratum sample fraction as a weight and making weighted averages yield the summary treatment_ control difference. 方法:将临床试验的每个中心看作一个层,以层样本分数为权作加权平均得综合治疗对照差。