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Na原子链表面等离激元特性的含时密度泛函研究
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作者 刘丹丹 杨帅权 张红 《原子与分子物理学报》 CAS 北大核心 2020年第3期403-408,共6页
本文用含时密度泛函理论研究了线性Na原子链的表面等离激元机理.主要在原子尺度下模拟计算了体系随着原子数增加及原子间距变化的集体激发过程.研究发现线性原子链有一个普遍的特性——存在一个纵模和两个横模.两个横模一般在实验上很... 本文用含时密度泛函理论研究了线性Na原子链的表面等离激元机理.主要在原子尺度下模拟计算了体系随着原子数增加及原子间距变化的集体激发过程.研究发现线性原子链有一个普遍的特性——存在一个纵模和两个横模.两个横模一般在实验上很难被观测到.纵模随着原子链长度增加,能量红移的同时,该纵模主峰的强度呈线性增长.随着原子个数的增加,端点模式(TE)开始蓝移,能量和偶极强度都逐渐趋向饱和.横模能量被劈裂的原因概括如下:(一)每个位置的电子受到的势不同,在两端的电子受到的势要比在中间的电子受到的势要高,因此两端的电荷积累也比中间多;(二)端点存在悬挂键,所以中间的电子-电子间相互作用与端点的不一样,这两方面又都与原子间距d有关. 展开更多
关键词 表面等离激元 线性Na原子链 中心 端点模 含时密度泛函理论
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A method for constraining the end effect of EMD based on sequential similarity detection and adaptive filter 被引量:2
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作者 Wei Dongdong Tang Wencheng 《Journal of Southeast University(English Edition)》 EI CAS 2021年第1期14-21,共8页
Aimed at the problem of the end effect when using empirical mode decomposition(EMD),a method for constraining the end effect of EMD is proposed based on sequential similarity detection and adaptive filter.The method d... Aimed at the problem of the end effect when using empirical mode decomposition(EMD),a method for constraining the end effect of EMD is proposed based on sequential similarity detection and adaptive filter.The method divides the signal into many wavelets,and it changes the initial wavelet length to select the best initial wavelet that has the minimum error and maximum number of matching seed wavelets,and the wavelet slopes are used for pre-matching and secondary matching to speed up the matching speed.Then,folded self-adaptive threshold is used to select multiple seed wavelets,and finally the end waveform is predicted and expanded according to the adaptive filter method.The proposed method is used to analyze the non-stationary nonlinear simulation signal and experimental signal,and it is compared with the mirror extension and RBF extension methods.The orthogonality index and similarity index of the EMD results of the extended signal after the proposed method are better than those of the other methods.The results show that the proposed method can better constrain the end effect,and has certain validity,accuracy and stability in solving the end effect problem. 展开更多
关键词 empirical mode decomposition(EMD) end effect sequential similarity detection adaptive filter
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Multi-Gradient Routing Protocol for Wireless Sensor Networks 被引量:3
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作者 Ying Qiu Shining Li +2 位作者 Zhigang Li Yu Zhang Zhe Yang 《China Communications》 SCIE CSCD 2017年第3期118-129,共12页
Sensor networks tend to support different traffic patterns since more and more emerging applications have diverse needs. We present MGRP, a Multi-Gradient Routing Protocol for wireless sensor networks, which is fully ... Sensor networks tend to support different traffic patterns since more and more emerging applications have diverse needs. We present MGRP, a Multi-Gradient Routing Protocol for wireless sensor networks, which is fully distributed and efficiently supports endto-end, one-to-many and many-to-one traffic patterns by effectively construct and maintain a gradient vector for each node. We further combine neighbor link estimation with routing information to reduce packet exchange on network dynamics and node failures. We have implemented MGRP on Tiny OS and evaluated its performance on real-world testbeds. The result shows MGRP achieves lower end-to-end packet delay in different traffic patterns compared to the state of the art routing protocols while still remains high packet delivery ratio. 展开更多
关键词 wireless sensor network routing protocol multi-gradient end-to-end traffic pattern
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Weighted estimates for the multilinear singular integral operators with non-smooth kernels 被引量:7
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作者 HU GuoEn1 & LU ShanZhen2 1Department of Applied Mathematics, Zhengzhou Information Science and Technology Institute, Zhengzhou 450002, China 2Department of Mathematics, Beijing Normal University, Beijing 100875, China 《Science China Mathematics》 SCIE 2011年第3期587-602,共16页
In this paper, by sharp function estimates and certain weak type endpoint estimates, the authors establish some weighted norm inequalities with Ap weights for the multilinear singular integral operators with non-smoot... In this paper, by sharp function estimates and certain weak type endpoint estimates, the authors establish some weighted norm inequalities with Ap weights for the multilinear singular integral operators with non-smooth kernels. 展开更多
关键词 approximation to the identity weighted norm inequality singular integral operator non-smooth kernel Calderón-Zygmund decomposition
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