期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
不同生态环境胁迫胡桃楸的演化结构比较研究 被引量:5
1
作者 陈丹萍 由继红 +4 位作者 刘丹丹 王晓钰 李岩 徐光照 陆静梅 《东北师大学报(自然科学版)》 CAS CSCD 北大核心 2018年第2期97-102,共6页
采用石蜡切片和光学显微技术,对吉林省阴生和阳生2种不同生态环境生长的胡桃楸叶片及叶柄解剖结构进行了比较研究,探讨了不同环境胁迫下胡桃楸叶片和叶柄颉颃逆境的演化结构规律.结果表明:阴生的胡桃楸叶片面积明显大于阳生的;阴生的胡... 采用石蜡切片和光学显微技术,对吉林省阴生和阳生2种不同生态环境生长的胡桃楸叶片及叶柄解剖结构进行了比较研究,探讨了不同环境胁迫下胡桃楸叶片和叶柄颉颃逆境的演化结构规律.结果表明:阴生的胡桃楸叶片面积明显大于阳生的;阴生的胡桃楸叶柄表皮细胞平均直径大于阳生的;阴生的胡桃楸叶栅栏组织细胞小、排列疏松,而阳生的叶栅栏组织细胞大、排列紧密;数理统计结构特征参数表现为阴生胡桃楸叶主脉及叶柄木质部管孔链平均长度均小于阳生的;阴生胡桃楸叶及叶柄已演化出颉颃荫湿逆境的解剖结构,这些结构特征均为植物体与荫蔽环境之间相互适应的结果. 展开更多
关键词 胡桃楸 逆境胁迫 解剖结构
下载PDF
Iterative Learning Control for a Class of Linear Continuous-time Switched Systems with Fixed Initial Shifts 被引量:2
2
作者 xu guang-zhao fu qin +3 位作者 du li-li wu jian-rong yu peng-fei li yong 《Communications in Mathematical Research》 CSCD 2018年第4期309-328,共20页
This paper deals with the problem of iterative learning control for a class of linear continuous-time switched systems in the presence of a fixed initial shift. Here, the considered switched systems are operated durin... This paper deals with the problem of iterative learning control for a class of linear continuous-time switched systems in the presence of a fixed initial shift. Here, the considered switched systems are operated during a finite time interval repetitively. According to the characteristics of the systems, a PD-type learning scheme is proposed for such switched systems with arbitrary switching rules, and the corresponding output limiting trajectories under the action of the PD-type learning scheme are given. Based on the contraction mapping method, it is shown that this scheme can guarantee the outputs of the systems converge uniformly to the output limiting trajectories of the systems over the whole time interval. Furthermore, the initial rectifying strategies are applied to the systems for eliminating the effect of the fixed initial shift. When the learning scheme is applied to the systems, the outputs of the systems can converge to the desired reference trajectories over a pre-specified interval. Finally, simulation examples illustrate the effectiveness of the proposed method. 展开更多
关键词 iterative learning control switched system PD-type learning scheme fixed initial shift output limiting trajectory
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部