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Low-modal-crosstalk doped-fiber amplifiers in few-mode-fiber-based systems

Photonics Research 2024年第8期12卷 1768-1775页

作者： SHUAILUO HUANG LEI SHEN GANG QIAO YUANPENG DING YUYANG GAO JIAN CUI BAOLONG ZHU SIYUAN LIU MINGQING ZUO JINGLONG ZHU LEI ZHANG JIE LUO YONGQI HE ZHANGYUAN CHEN JUHAO LI State Key Laboratory of Advanced Optical Communication Systems and Networks Peking UniversityBeijing 100871China State Key Laboratory of Optical Fiber and Cable Manufacture Technology Yangtze Optical Fibre and Cable Joint Stock Limited CompanyWuhan 430073China School of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China Department of Networks China Mobile Communications Group Co.Ltd.Beijing 100033China Department of Fundamental Network Technology China Mobile Research InstituteBeijing 100053China Pengcheng Laboratory Shenzhen 518055China

Independent light propagation through one or multiple modes is commonly considered as a basic demand for mode manipulation in few-mode fiber(FMF)-or multimode fiber(MMF)-based optical systems such as transmission links,optical fiber lasers,or distributed optical fiber ***,the insertion of doped-fiber amplifiers always kills the entire effort by inducing significant modal *** this paper,we propose the design of doped-fiber amplifiers in FMF-based systems adopting identical multiple-ring-core(MRC)index profiles for both passive and doped fibers to achieve low modal *** develop the direct-glass-transition(DGT)modified chemical vapor deposition(MCVD)processing for precise fabrication of few-mode erbium-doped fibers(FM-EDFs)with MRC profiles of both refractive index and erbium-ion doping ***,a few-mode erbium-doped-fiber amplifier(FM-EDFA)with a maximum gain of 26.08 dB and differential modal gain(DMG)of 2.3 dB is realized based on fabricated FM-EDF matched with a transmission FMF supporting four linearly polarized(LP)*** the insertion of the FM-EDFA,60+60 km simultaneous LP_(01)∕LP_(11)∕LP_(21)∕LP_(02)transmission without inter-modal multiple-input multiple-output digital signal processing(MIMO-DSP)is successfully *** proposed design of low-modal-crosstalk doped-fiber amplifiers provides,to our knowledge,new insights into mode manipulation methods in various applications.

关键词： fiber crosstalk amplifiers

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A Method to Simplify the Markov Model of Protective Systems

A Method to Simplify the Markov Model of Protective Systems

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IEEE Conference on Energy Internet and Energy System Integration (EI2)

作者： Xingzhu Wang Yongxin Chen Minghao Wen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China Grid Center State Grid Hubei Electric Power Research Institute Wuhan China

The state space approach is a common method for conducting reliability assessment of protective systems. However, as more factors affecting the reliability of protective relay are considered, the system Markov model is becoming more and more complex and its solving efficiency is decreasing. To avoid this, a method to simplify the Markov model of protective system is proposed in this paper. Based on the continuous-time Markov process (CTMP), the theory underlying the state space approach, the method illustrates that the duration of the protective system in the switching states can be neglected. In other words, the protection switching state can be ignored when developing a Markov model of protective system. This method is applied to two existing models, one for a protection/component system and the other for redundant protective systems. The study results show that the method significantly reduces the complexity of the Markov model and improves the solving efficiency without reducing the capability of Markov model to describe the reliability of protective systems.

关键词： Protection switching Protective relaying Switches System integration Markov processes Reliability theory Complexity theory

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OPTIMIZATION AND DESIGN OF T-TYPE SEALING STRUCTURE BASED ON COMPRESSION RATIO

OPTIMIZATION AND DESIGN OF T-TYPE SEALING STRUCTURE BASED ON...

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2024 CSAA/IET International Conference on Aircraft Utility Systems, AUS 2024

作者： Meng, Lihua Tang, Baoping Bao, Yunpeng Zhang, Chao Wang, Shaoping Chen, Rentong Avic China Aero-Polytechnology Establishment Department Beijing100028 China State Key Laboratory of Mechanical Transmission for Advanced Equipment Chongqing University Chongqing400030 China School of Automation Science and Electrical Engineering Beihang University Beijing100191 China Ningbo Institute of Technology Beihang University Ningbo315800 China

The structure of T-type sealing groove is one of the important factors affecting the sealing performance and service life. The traditional design of T-type sealing groove usually considers the transition fillet and the edge angle of the groove, but it is not analyzed and designed in combination with the groove depth ratio. Therefore, this paper proposes a groove depth structure design based on compression ratio. Firstly, a groove depth parameter model is established to describe the relationship between the compression ratio and the structural parameters of the T-seal groove. Then, a two-dimensional finite element analysis model is established to obtain the internal stress and maximum contact stress of the seal ring under different groove depth ratios. Finally, the life of the EPDM rubber ring is calculated according to the Ananios empirical formula. The results show that when the groove depth ratio is 25 %, the life of the EPDM rubber ring is the longest. © The Institution of engineering & technology 2024.

关键词： Compression ratio (machinery)

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Efficient Cutting of Submarine Pipelines by Linear-Shaped Charge 30th

Efficient Cutting of Submarine Pipelines by Linear-Shaped Ch...

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30th International Conference on Computational and Experimental engineering and Sciences, ICCES 2024

作者： Zhang, Shenhe Wang, Longkan Yang, Shuxin Zong, Zhi Zhang, Zhifan State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial Equipment School of Naval Architecture Engineering Dalian University of Technology Dalian116024 China China Ship Research and Development Academy Beijing100192 China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai200240 China

ISBN: (纸本)9783031687747

Directional explosive cutting method has been applied to the cutting, maintenance and even destruction of submarine pipelines because of the high cutting speed and low risk to adjacent components. This paper develops a three-dimensional numerical model for the damage effects on the pipe induced by the Linear-Shaped Charge (LSC). The explosive is 50 kg TNT. The internal diameter of the pipe is 871 mm, and the thickness of the steel wall is 34 mm. The standoff distance is set to 1.0 times the height of the LSC and an air cavity is added in front of the liner for better jet formation effect. The pipe is filled with air, and the bottom of the pipeline is anchored to the seabed. Due to the symmetry of the numerical model, a quarter of the numerical model is established in order to improve the calculating efficiency. The FSI (Fluid-Structure Interaction) is taken into consideration. Based on structured-arbitrary Lagrange Euler (S-ALE) method, the damage process of the pipeline under the coupling load of the jet penetration, hydrostatic pressure, shock wave and bubble is investigated. According to the numerical simulation results, the pipe is immediately destroyed under the combined effect of the load. The results indicate that it is possible to effectively cut the pipelines by using a linear-shaped charge technique. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Submarine pipelines

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NaNbO_(3) modulated phase transition behavior and antiferroelectric stability evolution in 0.88(Bi_(0.5)Na_(0.5))TiO_(3)-0.12BaTiO_(3) lead-free ceramics

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Journal of Materiomics 2022年第5期8卷 1067-1076页

作者： Yi Zhang Jian Fu Aiwen Xie Tianyu Li Xuewen Jiang Ruzhong Zuo Dou Zhang Institute of Electro Ceramics&Devices School of Materials Science and EngineeringHefei University of TechnologyHefei230009China Center for Advanced Ceramics School of Materials Science and EngineeringAnhui Polytechnic UniversityWuhu241000China State Key Laboratory of Power Metallurgy Central South UniversityChangshaHunan410083China

Giant strains in(Bi_(0.5)Na_(0.5))TiO_(3) based ceramics are usually attributed to electric field induced nonpolar to polar phase *** it is an ergodic relaxor R3c/P4mm ferroelectric(FE)to long-range ordered FE phase transformation or a reversible P4bm antiferroelectric(AFE)to FE phase transition is still ***,lead-free(0.88-x)(Bi_(0.5)Na_(0.5))TiO_(3)-0.12BaTiO_(3-x)NaNbO_(3) ceramics exhibit a compositionmodulated FE tetragonal P4mm to relaxor AFE tetragonal P4bm phase transition,in which double hysteresis loop,sprout-shaped S-E curves,near-zero quasi-static d33 together with a large volume change suggest the AFE characteristics of P4bm *** interesting finding is that the reversibility of fieldinduced AFE P4bm phase to FE P4mm phase transition strongly depends on the NN content,from being completely irreversible at x=0.01e0.02,to partially reversible at x=0.03e0.05,and finally to completely reversible at x=*** is indicated that the variation of reversibility should be attributed to the change of relative free energy caused by decreasing the FE to AFE phase transition temperature with increasing the NN content.

关键词： Lead-free ceramic Sodium bismuth titanate Strains Antiferroelectric stability

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Towards Practical Application of Li-S Battery with High Sulfur Loading and Lean Electrolyte:Will Carbon-Based Hosts Win This Race?

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Nano-Micro Letters 2023年第9期15卷 384-422页

作者： Yi Gong Jing Li Kai Yang Shaoyin Li Ming Xu Guangpeng Zhang Yan Shi Qiong Cai Huanxin Li Yunlong Zhao Advanced Technology Institute University of SurreyGuildfordSurrey GU27XHUK Department of Chemical and Process Engineering University of SurreyGuildford GU27XHUK Department of Chemistry Physical and Theoretical Chemistry LaboratoryUniversity of OxfordOxford OX13QZUK Department of Engineering University of Cambridge9 JJ Thomson AvenueCambridge CB30FAUK State Key Laboratory for Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082HunanPeople’s Republic of China College of Materials and Metallurgy Guizhou UniversityGuiyang 550025People’s Republic of China

As the need for high-energy–density batteries continues to grow, lithium-sulfur(Li–S) batteries have become a highly promising next-generation energy solution due to their low cost and exceptional energy density compared to commercially available Li-ion batteries. Research into carbon-based sulfur hosts for Li–S batteries has been ongoing for over two decades, leading to a significant number of publications and ***, the commercialization of Li–S batteries has yet to be realized. This can be attributed, in part, to the instability of the Li metal anode. However, even when considering just the cathode side, there is still no consensus on whether carbon-based hosts will prove to be the best sulfur hosts for the industrialization of Li–S batteries. Recently, there has been controversy surrounding the use of carbon-based materials as the ideal sulfur hosts for practical applications of Li–S batteries under high sulfur loading and lean electrolyte conditions. To address this question, it is important to review the results of research into carbon-based hosts, assess their strengths and weaknesses, and provide a clear perspective. This review systematically evaluates the merits and mechanisms of various strategies for developing carbon-based host materials for high sulfur loading and lean electrolyte conditions. The review covers structural design and functional optimization strategies in detail, providing a comprehensive understanding of the development of sulfur hosts. The review also describes the use of efficient machine learning methods for investigating Li–S batteries. Finally, the outlook section lists and discusses current trends, challenges, and uncertainties surrounding carbon-based hosts, and concludes by presenting our standpoint and perspective on the subject.

关键词： Li-S batteries Carbon materials Structural design Functional modification Machine learning

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Electrochemical CO_(2) reduction with ionic liquids: review and evaluation

Industrial Chemistry & Materials

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Industrial Chemistry & Materials 2023年第3期1卷 410-430页

作者： Yangshuo Li Fangfang Li Aatto Laaksonen Chuan Wang Paul Cobden Per Boden Yanrong Liu Xiangping Zhang Xiaoyan Ji Energy Engineering Division of Energy ScienceLulea University of TechnologyLuleå97187Sweden Department of Materials and Environmental Chemistry Arrhenius LaboratoryStockholm University10691 StockholmSweden Centre of Advanced Research in Bionanoconjugates and Biopolymers Petru Poni Institute of Macromolecular ChemistryAleea Grigore Ghica-Voda41A700487 IasiRomania State Key Laboratory of Materials-Oriented and Chemical Engineering Nanjing Tech UniversityNanjing210009P.R.China University of Cagliari Department of Chemical and Geological SciencesCampus MonserratoSS 554 bivio per Sestu09042MonserratoItaly Metallurgy Department Swerim AB97125LuleåSweden SMA Mineral AB 68227FilipstadSweden CAS Key Laboratory of Green Process and Engineering Beijing Key Laboratory of Ionic Liquids Clean ProcessState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China

The increasing CO_(2) emission,as the chief culprit causing numerous environmental problems,could be addressed by the electrochemical CO_(2) reduction(CO_(2)R)to the added-value carbon-based *** liquids(ILs)as electrolytes and co-catalysts have been widely studied to promote CO_(2)R owing to their unique *** the potential products of CO_(2)R,those only containing one carbon atom,named C1 products,including CO,CH_(3)OH,CH_(4),and syngas,are easier to achieve than *** this study,we first summarized the research status on CO_(2)R to these C1 products,and then,the state-of-theart experimental results were used to evaluate the economic potential and environmental *** the rapid development in CO_(2)R,future scenarios with better CO_(2)R performances were reasonably assumed to predict the future business for each *** the studied C1 products,the research focuses on CO,where satisfactory results have been *** evaluation shows that producing CO via CO_(2)R is the only profitable route at ***3OH and syngas of H2/CO(1:1)as the targeted products can become profitable in the foreseen *** addition,the life cycle assessment(LCA)was used to evaluate the environmental impact,showing that CO_(2)R to CH4 is the most environmentally friendly pathway,followed by the syngas of H_(2)/CO(2:1)and CO,and the further improvement of the CO_(2)R performance can make all the studied C1 products more environmentally ***,CO is the most promising product from both economic and environmental impact aspects.

关键词： Electrochemical-CO_(2)-reduction Ionic-liquids C1-product Economic-evaluation Environmental-impact

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A Range Alignment Method Using Deep Learning for MMW ISAR Imaging

A Range Alignment Method Using Deep Learning for MMW ISAR Im...

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Frontiers of Electronic, Electrical and Information engineering (ICFEEIE), International Conference on the

作者： Chaofan Zhao Chunguang Ma Xu Chen Y ong Luoab School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu Sichuan China School of Electronic Science and Engineering UESTC Chengdu Sichuan China State Key Laboratory of Electromagnetic Space Cognition and Intelligent Control Technology Beijing China

ISBN: (数字)9798331528300

ISBN: (纸本)9798331528317

Range alignment is an important step in the imaging process of inverse synthetic aperture radar (ISAR) radar. In this paper, a novel deep learning network model is proposed to effectively tackle the challenge of distance alignment in millimeter-wave (MMW) ISAR imaging. The proposed model leverages a multi-layer bidirectional long short-term memory (bi-LSTM) network architecture to learn intricate features among echoes, thus facilitating precise alignment along the range direction. Meanwhile transfer learning was used to enhance the adaptability of the model to multiple signal-to-noise ratios (SNR). Experiment results show that the aligned images generated by proposed model in this paper are closer to the reference images in low SNR environments compared to traditional methods.

关键词： Deep learning Adaptation models Simulation Transfer learning Imaging Radar imaging Network architecture Millimeter wave radar Inverse synthetic aperture radar Signal to noise ratio

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Adaptive energy-preserving algorithms for guiding center system

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Plasma Science and technology 2023年第4期25卷 11-22页

作者：朱贝贝刘健张嘉炜祝爱卿唐贻发 Department of Applied Mathematics School of Mathematics and PhysicsUniversity of Science and Technology BeijingBeijing 100083Peopleʼs Republic of China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230026Peopleʼs Republic of China Advanced algorithm Joint Lab Shandong Computer Science CenterQilu University of TechnologyJinan 250014Peopleʼs Republic of China The State Key Laboratory of Scientific and Engineering Computing The Institute of Computational Mathematics and Scientific/Engineering ComputingAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190Peopleʼs Republic of China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049Peopleʼs Republic of China

We develop two types of adaptive energy preserving algorithms based on the averaged vector field for the guiding center dynamics,which plays a key role in magnetized *** adaptive scheme is applied to the Gauss Legendre’s quadrature rules and time stepsize respectively to overcome the energy drift problem in traditional energy-preserving *** new adaptive algorithms are second order,and their algebraic order is carefully *** results show that the global energy errors are bounded to the machine precision over long time using these adaptive algorithms without massive extra computation cost.

关键词： guiding center system energy-preserving methods adaptive energy conservation

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Surface Oxygen Vacancy and Hydride Species on Ceria Are Detrimental to Acetylene Semihydrogenation Reaction

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ACS Catalysis 2023年第8期13卷 5213-5224页

作者： Li, Zhaorui Chen, Lu Wu, Zongfang Jia, AiPing Shi, Shucheng Zhang, Hui Wang, Jia Liu, Zhi Shao, Wei-Peng Yang, Fan Wu, Xin-Ping Gong, Xue-Qing Huang, Weixin Key Laboratory of Precise and Intelligent Chemistry iChEM Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes Department of Chemical Physics University of Science and Technology of China Hefei 230026 China Key Laboratory for Advanced Materials and Joint International Research Laboratory for Precision Chemistry and Molecular Engineering Feringa Nobel Prize Scientist Joint Research Center Centre for Computational Chemistry and Research Institute of Industrial Catalysis School of Chemistry and Molecular Engineering East China University of Science and Technology Shanghai 200237 China Hefei National Research Center for Physical Science at the Microscale Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes University of Science and Technology of China Hefei 230026 China Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Institute of Physical Chemistry Zhejiang Normal University Jinhua 321004 China School of Physical Science and Technology Shanghai Tech University Shanghai 201210 China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 China Dalian National Laboratory for Clean Energy Chinese Academy of Sciences Dalian 116023 China

Reactivity of OH and hydride species in oxide-catalyzed hydrogenation reactions has attracted great interest. Herein, we report a combined in situ spectroscopic characterization and density functional theory (DFT) calculation study of ceria-catalyzed acetylene semihydrogenation reaction. The ceria surface is fully hydroxylated during the adopted reaction condition. C₂H₂ adsorbs molecularly on the stoichiometric CeO₂ surface and hydrogenates with OH groups selectively to produce C₂H₄. Semihydrogenation of C₂H₂ to C₂H₄ with either OH groups or hydride species on ceria surfaces with surface oxygen vacancies proceeds more facilely than on a stoichiometric CeO₂ surface, but C₂H₄ adsorbs more strongly and further hydrogenates to C₂H₆ more facilely;moreover, dissociative adsorption of C₂H₂ to C₂H species occurs, which facilely hydrogenates with the hydride species eventually to form C₂H₆ and react with each other to produce oligomers, decreasing the catalytic selectivity and stability, respectively. These results demonstrate that the ceria catalyst with a stoichiometric surface is extremely selective in catalyzing C₂H₂ semihydrogenation reaction to C₂H₄, whereas surface oxygen vacancies or hydride species on ceria are harmful to the catalytic performance. © 2023 American Chemical Society.

关键词： active species DFT calculations heterogeneous catalysis in situ characterization reaction mechanism

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