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Temperature stability of magnetic field for periodic permanent-magnet focusing system

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Rare Metals 2014年第2期33卷 180-184页

作者： Li Li Jian-Ya Chen Yun-Jie Liu Beijing Key laboratory of network System Architecture and Convergence Beijing University of Posts and Telecommunications

In this study, finite element analysis based on an Ansoft Maxwell software was used to reveal the temperature stability of a magnet ring and the equivalent structural periodic permanent-magnet（PPM） focusing system. It is found that with the temperature increasing, the decrease rate of magnetic induction peak（Bz）maxof single magnet ring is greater than that of remanence Brof magnet in the range from room temperature to 200 °C, however,the PPM focusing system do have the same temperature characteristics of permanent-magnet materials. It indicates that the magnetic temperature properties of the PPM system can be effectively controlled by adjusting the temperature properties of the magnets. Moreover, the higher permeability of the magnets indicates the less Hcb, giving rise to lower magnetic induction peak （Bz）′max： Finally, it should be noted that the magnetic orientation deviation angle θ（／15°） of permanent magnets has little effect on the focusing magnetic field of the PPM system at different temperatures and the temperature stability. The obtained results are beneficial to the design and selection of permanent magnets for PPM focusing system.

关键词： Periodic permanent-magnets focusing system Rare earth permanent magnets Finite element simulation Temperature stability Wireless underground sensor network

Chinese Pathogen Identification Net:A laboratory network for Surveillance and Response of Bacterial Infectious Diseases

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China CDC weekly 2022年第12期4卷 235-237页

作者： Zhigang Cui Haijian Zhou Shuang Meng Xiaoli Du Jianguo Xu Biao Kan National Institute for Communicable Disease Control and Prevention Chinese Center for Disease Control and PreventionBeijingChina State Key laboratory of Infectious Disease Prevention and Control BeijingChina

Infectious diseases are a sustained threat to social development and public *** infectious diseases,including plague,cholera,anthrax,brucellosis,typhoid fever,meningitis,and even those caused by antimicrobial-resistant bacteria,have been prevalent around the world for a long time,and still trigger outbreaks and long-term epidemics in different countries or regions nowadays(1),and trans-regional spread of diseases has frequently exhibited epidemic patterns.

关键词： sustained diseases fever

Investigation on the intensity noise characteristics of the semiconductor ring laser

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Chinese Physics B 2014年第2期23卷 262-269页

作者：康泽新蔡鑫伦温晓东刘超简水生余思远 Key laboratory of All Optical network & Advanced Telecommunication network of EMC Institute of Lightwave TechnologyBeijing Jiaotong University The Department of Electrical and Electronic Engineering University of Bristol

Based on the frequency-domain multimode theoretical model, detailed investigations on the noise characteristic of the semiconductor ring laser （SRL） are first performed in this paper. The comprehensive nonlinear terms related to the third order nonlinear susceptibility Z3 are included in this model; the Langevin noise sources for electric field and carrier density fluctuations are also taken into account. As the injection current increases, the SRL may present several operation regimes. Remarkable and unusual low frequency noise enhancement in the form of a broad low frequency tail extending all the way to the relaxation oscillation peak is observed in any of the operation regimes of SRLs. The influences of the backscattering coefficient on the relative intensity noise （RIN） spectrum in typical operation regimes are investigated in detail.

关键词： semiconductor ring laser relative intensity noise low frequency noise enhancement

An Unprecedented Efficiency with Approaching 21%Enabled by Additive‑Assisted Layer‑by‑Layer Processing in Organic Solar Cells

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Nano-Micro Letters 2025年第2期17卷 372-375页

作者： Shuai Xu Youdi Zhang Yanna Sun Pei Cheng Zhaoyang Yao Ning Li Long Ye Lijian Zuo Ke Gao Key laboratory of Advanced Green Functional Materials College of ChemistryChangchun Normal UniversityChangchun 130032People’s Republic of China Shandong Provincial Key laboratory for Science of Material Creation and Energy Conversion School of Chemistry and Chemical EngineeringShandong UniversityQingdao 266237People’s Republic of China College of Polymer Science and Engineering Sichuan UniversityChengdu 610065People’s Republic of China State Key laboratory and Institute of Elemento‑Organic Chemistry Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer MaterialsRenewable Energy Conversion and Storage Center(RECAST)College of ChemistryNankai UniversityTianjin 300071People’s Republic of China Institute of Polymer Optoelectronic Materials and Devices State Key laboratory of Luminescent Materials and Devices South China University of TechnologyGuangzhou 510640People’s Republic of China Tianjin Key laboratory of Molecular Optoelectronic Sciences School of Materials Science and EngineeringTianjin UniversityTianjin 300350People’s Republic of China State Key laboratory of Silicon Materials MOE Key Laboratory of Macromolecular Synthesis and FunctionalizationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China

Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network active layer morphology,featuring a bulk p-in structure and proper vertical segregation achieved through additive-assisted layer-by-layer *** optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion,reduces recombination losses,and enhances light capture *** approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.

关键词： Organic solar cells Additive-assisted layer-by-layer processing Three-dimensional fibril morphology Bulk p-i-n structure Optical management

Magic Mark: a marking menu using 2D direction and 3D depth information

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Science China(Information Sciences) 2018年第6期61卷 238-240页

作者： Fei LYU Rui XI Yuxin HAN Yujie LIU School of Digital Media and Design Arts Beijing University of Posts and Telecommunications Beijing Key laboratory of network Systems and network Culture Beijing University of Posts and Telecommunications

Menus are important interactive components of user interfaces,broadly applied to command exploration and selection[1].For large displays,RapMenu and touchless circular menus explored the design space of tilt and 2D direction[2,3].However,as one of the important input modalities,3D depth information has not been fully utilized for menu control in large displays.

关键词： Magic Mark Figure

Fault tolerant quantum secure direct communication with quantum encryption against collective noise

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Chinese Physics B 2012年第10期21卷 101-109页

作者：黄伟温巧燕贾恒越秦素娟高飞 State Key laboratory of networking and Switching Technology Beijing University of Posts and Telecommunications State Key laboratory of Integrated Services network Xidian University

We present two novel quantum secure direct communication（QSDC） protocols over different collective-noise *** from the previous QSDC schemes over collective-noise channels,which are all source-encrypting protocols,our two protocols are based on *** both schemes,two authorized users first share a sequence of EPR pairs as their reusable quantum *** they use their quantum key to encrypt and decrypt the secret message carried by the decoherence-free states over the collective-noise *** theory,the intrinsic efficiencies of both protocols are high since there is no need to consume any entangled states including both the quantum key and the information carriers except the ones used for eavesdropping *** checking eavesdropping,the two parties only need to perform two-particle measurements on the decoy states during each ***,we make a security analysis of our two protocols and demonstrate that they are secure.

关键词： quantum cryptography quantum secure direct communication quantum encryption collective noise

A trust framework based smart aggregation for machine type communication

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Science China(Information Sciences) 2017年第10期60卷 78-92页

作者： Tabinda SALAM Waheed ur REHMAN Xiaofeng TAO Yu CHEN Ping ZHANG National Engineering laboratory for Mobile network Technologies Beijing University of Posts and Telecommunication Department of Computer Science University of Peshawar

Machine type communication(MTC) is one of the significant communication paradigms in the fifth generation networks. The existing cellular networks are not designed for massive access of the MTC ***, data aggregation and relaying are advocated to reduce the massive MTC access besides other physical layer solutions. In this paper, we propose a secured multiple mobile relay selection algorithm that smartly aggregates data from adjacent MTC devices through multiple user equipments and transmits it to the base station(BS). The paper also presents a framework for the selection of trusted relays to cooperatively aggregate MTC data and render two-hop connectivity to the BS. Our proposed algorithm is compared with existing algorithms on the basis of energy efficiency, system capacity, communication delay and outage probability. Our proposed algorithm outperforms the other schemes by improving outage probability and communication delay by 33% and 25%, respectively.

关键词： D2D communication data aggregation machine type communication(MTC) mobile relay MTC offloading

A high power efficiency method using orthogonal signal decomposition in high PAPR system

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Science China(Information Sciences) 2013年第4期56卷 173-179页

作者： REN ZhiYuan LI YongZhao ZHANG HaiLin HAN Kun State Key laboratory of Integrated Services network Xidian University Xi'an Communication Institute

To solve the low-power-efficiency problem for high peak to average power ratio systems,such as OFDM,an orthogonal inhomogeneous signal decomposition approach is proposed in this *** novel method decomposes the signal into branch signals orthogonally,which can adapt to the change of saturate power of each branch power ***,the novel method has the advantages of both high power efficiency of power amplifier and low PAPR of branch ***,this is more suitable for practical *** simulation results indicate that the proposed method can increase the power efficiency remarkably without reducing the BER performance in the receiver.

关键词： green radio power amplifier orthogonal inhomogeneous signal decomposed power efficiency energy conservation

An improved Durandal signature scheme

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Science China(Information Sciences) 2020年第3期63卷 140-155页

作者： Yongcheng SONG Xinyi HUANG Yi MU Wei WU Fujian Provincial Key laboratory of network Security and Cryptology College of Mathematics and InformaticsFujian Normal University

Constructing secure and effective code-based signature schemes has been an open problem. In this paper, we efficiently reduce the key size of the Durandal signature scheme introduced by Aragon et al.(EUROCRYPT 2019). We prove that the improved scheme is EUF-CMA secure by reducing its security to the advanced product spaces subspaces indistinguishability(PSSI+) problem, the decisional rank syndrome decoding(DRSD) problem, and the affine rank syndrome decoding(ARSD) problem under the random oracle model. Furthermore, our signature scheme is more secure than the Durandal scheme because recovering key attacks are equivalent to solving the rank syndrome decoding(RSD) problem, instead of the rank support learning(RSL) problem in the original Durandal scheme. Our signature scheme takes less time to generate a signature owing to the fact that our signature scheme enjoys smaller security parameters in comparison to the Duradual scheme. We compare the new scheme with existing code-based signature schemes and find that our signature scheme has advantages in terms of the public key size.

关键词： post-quantum cryptography code-based cryptography rank metric digital signatures provable security