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Orbital angular momentum conversion of acoustic vortex beams via planar lattice coupling

CHINESE PHYSICS B 2024年第9期33卷 413-420页

作者： Han, Qingbang Liu, Zhipeng Yin, Cheng Wu, Simeng Luo, Yinlong Yang, Zixin Pan, Xiuyang Wang, Yiqiu Kan, Xuefen Zhang, Yuqiu Yu, Qiang Wu, Jian Hohai Univ Coll Informat Sci & Engn Changzhou 213200 Peoples R China natl Univ Def technol Coll Adv Interdisciplinary Studies Nanhu Laser Lab Changsha 410073 Peoples R China Chinese Acad Sci Suzhou Inst Nanotech & Nanob i Lab Suzhou 215123 Peoples R China Jiangsu Shipping Coll Sch Transportat Engn Nantong 226010 Peoples R China

Orbital angular momentum (OAM) conversion is critical in understanding interactions between a structural sound field and a planar lattice. Herein, we explore the evolution of a monochromatic acoustic vortex beam (AVB) that is scattered by a phononic crystal (PnC) or a correlated random lattice. The phenomenon is ascribed to the enhanced orbit-orbit angular momentum coupling induced by the band structure. By modifying the coupling condition, accurate and continuous micro-manipulation of AVBs can be achieved, including the transverse/lateral gravity shift, the dynamics of the phase singularities, and the spatial distribution of acoustic pressure, etc. This research provides insight to the inhomogeneous coupling of AVBs with both propagating Bloch waves and localized Anderson modes, and may facilitate development of novel OAM-based acoustic devices for active sound field manipulation.

关键词： acoustic vortex beam phononic crystal Anderson localization Imbert-Fedorov effect 43.40.+s 43.20.+g 46.40.-f 46.40.Cd

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Nanoscale phase management of the 2D/3D heterostructure toward efficient perovskite solar cells

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SCIENCE BULLETIN 2024年第18期69卷 2853-2861页

作者： Gu, Hao Zhu, Annan Xia, Junmin Li, Wang Zheng, Jiahao Yang, Tao Li, Shengwen Zhang, Nan Mei, Shiliang Cai, Yongqing Chen, Shi Liang, Chao Xing, Guichuan Univ Macau Inst Appl Phys & Mat Engn Joint Key Lab Minist Educ Macau 999078 Peoples R China Nanjing Univ Posts & Telecommun NUPT State Key Lab Organ Elect & Informat Displays Nanjing 210023 Peoples R China Nanjing Univ Posts & Telecommun NUPT Inst Adv Mat IAM Jiangsu Natl Synerget Innovat Ctr Adv Mat SICAM Nanjing 210023 Peoples R China Xi An Jiao Tong Univ Sch Phys Natl Innovat Platform Ctr Ind Educ Integrat Energy MOE Key Lab Nonequilibrium Synth & Modulat Condens Xian 710049 Peoples R China Harbin Inst technol Minist Ind & Informat Technol Key Lab Semicond Optoelect Mat & Intelligent Photo Key Lab Micronano Optoelect Informat Syst Shenzhen 518055 Peoples R China Fudan Univ Inst Elect Light Sources Sch Informat Sci & Technol Shanghai 200433 Peoples R China

The stabilization of the formamidinium lead iodide (FAPbI(3)) structure is pivotal for the development of efficient photovoltaic devices. Employing two-dimensional (2D) layers to passivate the threedimensional (3D) perovskite is essential for maintaining the a-phase of FAPbI(3) and enhancing the power conversion efficiency (PCE) of perovskite solar cells (PSCs). However, the role of bulky ligands in the phase management of 2D perovskites, crucial for the stabilization of FAPbI(3), has not yet been elucidated. In this study, we synthesized nanoscale 2D perovskite capping crusts with = 1 and 2 RuddlesdenPopper (RP) perovskite layers, respectively, which form a type-II 2D/3D heterostructure. This heterostructure stabilizes the alpha-phase of FAPbI(3), and facilitates ultrafast carrier extraction from the 3D perovskite network to transport contact layer. We introduced tri-fluorinated ligands to mitigate defects caused by the halide vacancies and uncoordinated Pb2+ ions, thereby reducing nonradiative carrier recombination and extending carrier lifetime. The films produced were incorporated into PSCs that not only achieved a PCE of 25.39% but also maintained 95% of their initial efficiency after 2000 h of continuous light exposure without encapsulation. These findings underscore the effectiveness of a phase-pure 2D/3D heterostructure-terminated film in inhibiting phase transitions passivating the iodide anion vacancy defects, facilitating the charge carrier extraction, and boosting the performance of optoelectronic devices. (c) 2024 Science China Press. Published by Elsevier B.V. and Science China Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

关键词： Phase-pure 2D perovskite 2D/3D heterostructure Type-II energy alignment Carrier dynamic FAPbI(3) CARRIER DYNAMICS PASSIVATION HETEROJUNCTION PERFORMANCE STABILITY

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Meaningful String Extraction Based on Clustering for Improving Webpage Classification

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China Communications 2012年第3期9卷 68-77页

作者： Chen Jie Tan Jianlong Liao Hao Zhou Yanquan Beijing Univ Posts & Telecommun Beijing 100876 Peoples R China Chinese Acad Sci Inst Comp Technol Beijing 100190 Peoples R China natl engn lab informat secur technol Beijing 100190 Peoples R China

Since webpage classification is different from traditional text classification with its irregular words and phrases,massive and unlabeled features,which makes it harder for us to obtain effective *** cope with this problem,we propose two scenarios to extract meaningful strings based on document clustering and term clustering with multi-strategies to optimize a Vector Space Model(VSM) in order to improve webpage *** results show that document clustering work better than term clustering in coping with document ***,a better overall performance is obtained by spectral clustering with document ***,owing to image existing in a same webpage with document content,the proposed method is also applied to extract image meaningful terms,and experiment results also show its effectiveness in improving webpage classification.

关键词： webpage classification meaningfulstring extraction document clustering term cluste-ring k-means spectral clustering

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Editorial: Special issue on “mobile edge computing”

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Digital Communications and Networks 2020年第2期6卷 187-188页

作者： Chatzimisios, Periklis Granelli, Fabrizio Abid, Riduan M. Alexander TEl Thessaloniki ATEITHE Comp Syst Secur & Networks CSSN Res Lab Thessaloniki Greece Alexander TEl Thessaloniki ATEITHE Dept Informat Thessaloniki Greece Univ Trento Dept Informat Engn & Comp Sci DISI Trento Italy European Inst Innovat & technol ICT Labs Consortium Framework Budapest Hungary DISI Dept Educ Trento Italy Univ Estadual Campinas Campinas SP Brazil Univ Tokyo Tokyo Japan Al Akhawayn Univ Comp Sci Ifrane Morocco Auburn Univ Auburn AL 36849 USA

Mobile Edge Computing(MEC)has seen its fast growth in the past ***,taking advantage of the computation capabilities in edge devices,elegantly offloads the computation burden from cloud computing,but provides a much improved end-to-end *** has a wide range of applications,such as 5G wireless networking,Internet of Things(IoT),and collaborative autonomous *** big need driving the future MEC is new network communications,architectures,and protocols that enable the data to move and compute in the mobile edge devices and networks.

关键词： mobile IoT network

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ENABLING technolOGIES FOR AGILE MARITIME COMMUNICATION NETWORKS

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China Communications 2020年第3期17卷 I0001-I0003页

作者： Wei Feng Bin Lin Yunfei Chen Cheng-Xiang Wang Shengming Jiang Yuguang Fang Tsinghua Univ Dept Elect Engn Beijing Peoples R China Dalian Maritime Univ Dept Informat Sci & Technol Dalian Peoples R China George Washington Univ Washington DC USA Univ Warwick Coventry W Midlands England Hamburg Univ technol Hamburg Germany Siemens AG Mobile Phones Munich Germany Univ Agder Grimstad Norway Heriot Watt Univ Edinburgh Midlothian Scotland Southeast Univ Nanjing Peoples R China Purple Mt labs Nanjing Peoples R China IET London England Clarivate Analyt Philadelphia PA USA Shanghai Maritime Univ Coll Informat Engn Shanghai Peoples R China Nanjing Petr Transportat Co Nanjing Peoples R China Hong Kong Univ Sci & technol Dept Elect & Elect Engn Hong Kong Peoples R China Hong Kong Univ Sci & technol Comp Sci Dept Hong Kong Peoples R China natl Univ Singapore Ctr Wireless Commun Singapore Singapore lab Inst Infocomm Res I2R Singapore Singapore Univ Glamorgan Pontypridd M Glam Wales South China Univ technol Guangzhou Guangdong Peoples R China Univ Florida Dept Elect & Comp Engn Gainesville FL 32611 USA IEEE Piscataway NJ USA AAAS Washington DC USA

With the rapid development of maritime activities,there has been a growing demand for high data rate and ultra-reliable maritime ***,maritime communication services are provided mostly by maritime *** some places,shore and island-based base stations(BSs)can also be built to extend the coverage of terrestrial networks,providing the fourth-generation(4G)or even the fifth-generation(5G)*** further build up communication networks over the ocean for better coverage,unmanned aerial vehicles(UAVs)-aided and ship-borne BSs can be exploited to serve as supplementary relaying nodes.

关键词： communication networks island

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Geological Disaster Monitoring System Based on WSN and GSM Dual-network Integration technology

Geological Disaster Monitoring System Based on WSN and GSM D...

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14th IEEE International Conference on Communication technology (ICCT)

作者： Jing Shi-yong Bao Jing-fu Wu Fei Yang Ting UESTC Sch Elect Engn Chengdu Peoples R China UESTC Sch Commun & Informat Engn Chengdu Peoples R China Changsha Univ Sch Foreign Languages Changsha Hunan Peoples R China

ISBN: (纸本)9781467321013;9781467321006

According to time-consuming, difficulty and network building complication problem for traditional geological disaster monitoring methods, on the basis of the study of wireless sensor network (WSN) and Zigbee standard protocol, the paper presents a real-time and online geological disaster monitoring system architecture applied WSN and mobile communication network (GSM) dual-network integration technology. It has realized hardware and software design of the system architecture that provides an excellent project reference for China to build the ubiquitous networks of mobile communication network and sensor network integration.

关键词： wireless sensor ne twork (WSN) dual-network integration technology GSM network internet of things Zigbee standard protocol GPS ubiquitous networks

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