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刚-柔嵌段共聚物在有序排列的微米圆盘表面自组装构筑多级结构 被引量:1
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作者 李飞燕 唐政敏 +1 位作者 蔡春华 林嘉平 《功能高分子学报》 CAS CSCD 北大核心 2019年第3期292-299,共8页
在材料表面构筑聚合物多级结构可以显著提升其性能并赋予新的性能,但是目前已有的制备方法较为繁琐,需要开发简单易行的新方法。结合聚苯乙烯(PS)的可控蒸发组装和聚(γ-苄基-L-谷氨酸酯)-聚乙二醇(PBLG-b-PEG)刚-柔嵌段共聚物溶液自组... 在材料表面构筑聚合物多级结构可以显著提升其性能并赋予新的性能,但是目前已有的制备方法较为繁琐,需要开发简单易行的新方法。结合聚苯乙烯(PS)的可控蒸发组装和聚(γ-苄基-L-谷氨酸酯)-聚乙二醇(PBLG-b-PEG)刚-柔嵌段共聚物溶液自组装方法,在硅片表面构建了梯度排列且表面具有纳米条纹的微米圆盘多级结构。采用光学显微镜、原子力显微镜(AFM)和接触角测量仪等对微结构形貌及硅片的表面润湿性进行了表征。PS溶液经可控蒸发自组装在硅片表面形成梯度变化的微米圆点图案,经热处理及溶剂清洗后,得到微米圆盘。通过溶液自组装方法,PBLG-b-PEG在PS微米圆盘表面形成有序排列的周期性纳米条纹。材料的接触角随着图案表面微结构从半球状圆点到表面平整的圆盘再到表面带有纳米条纹的圆盘的变化持续降低。 展开更多
关键词 刚-柔嵌段共聚物 自组装 多级结构 微米圆盘 纳米条纹
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Analysis and Experiments on Two Linear Discriminant Analysis Methods
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作者 Xu Yong Jin Zhong +2 位作者 Yang Jingyu tang zhengmin Zhao Yingnan 《工程科学(英文版)》 2006年第3期37-47,共11页
Foley-Sammon linear discriminant analysis (FSLDA) and uncorrelated linear discriminant analysis (ULDA) are two well-known kinds of linear discriminant analysis. Both ULDA and FSLDA search the kth discriminant vector i... Foley-Sammon linear discriminant analysis (FSLDA) and uncorrelated linear discriminant analysis (ULDA) are two well-known kinds of linear discriminant analysis. Both ULDA and FSLDA search the kth discriminant vector in an n-k+1 dimensional subspace, while they are subject to their respective constraints. Evidenced by strict demonstration, it is clear that in essence ULDA vectors are the covariance-orthogonal vectors of the corresponding eigen-equation. So, the algorithms for the covariance-orthogonal vectors are equivalent to the original algorithm of ULDA, which is time-consuming. Also, it is first revealed that the Fisher criterion value of each FSLDA vector must be not less than that of the corresponding ULDA vector by theory analysis. For a discriminant vector, the larger its Fisher criterion value is, the more powerful in discriminability it is. So, for FSLDA vectors, corresponding to larger Fisher criterion values is an advantage. On the other hand, in general any two feature components extracted by FSLDA vectors are statistically correlated with each other, which may make the discriminant vectors set at a disadvantageous position. In contrast to FSLDA vectors, any two feature components extracted by ULDA vectors are statistically uncorrelated with each other. Two experiments on CENPARMI handwritten numeral database and ORL database are performed. The experimental results are consistent with the theory analysis on Fisher criterion values of ULDA vectors and FSLDA vectors. The experiments also show that the equivalent algorithm of ULDA, presented in this paper, is much more efficient than the original algorithm of ULDA, as the theory analysis expects. Moreover, it appears that if there is high statistical correlation between feature components extracted by FSLDA vectors, FSLDA will not perform well, in spite of larger Fisher criterion value owned by every FSLDA vector. However, when the average correlation coefficient of feature components extracted by FSLDA vectors is at a low level, the performance of FSLDA are comparable with ULDA. 展开更多
关键词 Fisher判据 Foley-Sammon线性判别分析 相关系数 不相关线性判别分析 判别向量
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东北交通大学——不应消失的教育品牌
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作者 唐政敏 《兰台世界》 2020年第3期115-117,共3页
东北交通大学成立于1926年,是锦州地区历史上可追溯的第一所大学,也是东北地区的第一所国立大学。东北交通大学以"造就交通管理专门人才"为宗旨,其创办具有十分重要的历史意义。科学发掘和合理保护利用东北交通大学文化遗产,... 东北交通大学成立于1926年,是锦州地区历史上可追溯的第一所大学,也是东北地区的第一所国立大学。东北交通大学以"造就交通管理专门人才"为宗旨,其创办具有十分重要的历史意义。科学发掘和合理保护利用东北交通大学文化遗产,具有很高的史料传承价值和现代教育意义。 展开更多
关键词 东北交通大学 教育品牌 文化遗产
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