检索结果-内蒙古大学图书馆

Generalized Equalization-Enhanced Phase Noise in Coherent Optical Transceivers Using Arbitrary Raised Cosine Filters

引用

JOURNAL OF LIGHTWAVE technology 2025年第2期43卷 620-626页

作者： Liu, Yuheng Yi, Xingwen Zhang, Jing Lu, Guo-Wei Li, Fan Sun Yat Sen Univ Sch Elect & Informat Technol Guangdong Prov Key Lab Opto Elect Informat Proc Ch Guangzhou 510275 Peoples R China Bangor Univ Sch Comp Sci & Engn Bangor LL57 1UT Wales Univ Elect Sci & Technol China Key Lab Opt Fiber Sensing & Commun Chengdu 610000 Sichuan Peoples R China Kyushu Univ Inst Mat Chem & Engn Fukuoka 8168580 Japan

Equalization-enhanced phase noise (EEPN) can degrade the performance of high baud-rate and long-distance coherent optical transmission systems that use electronic dispersion compensation (EDC). Existing theoretical calculations of EEPN are based on the ideal Nyquist filter, which has an unrealizable brickwall response due to its infinite time-domain extent. In this paper, we generalize the EEPN calculation for coherent optical transceivers using arbitrary raised cosine (RC) filters. We demonstrate that when the roll-off factor changes from zero to non-zero, the unitary transmission channel assumption no longer holds in the presence of EEPN. We calculate the resulting energy loss for transceivers using RC filters with arbitrary roll-off factors. The results indicate that while the intra-symbol EEPN remains almost unchanged, the inter-symbol EEPN and the total EEPN decrease with increasing bandwidth. Furthermore, we extend our analysis to high-order modulation formats, where the EEPN distribution varies depending on the moduli of the constellation clusters.

关键词： Filters Symbols Optical fiber dispersion Phase noise Optical fibers Energy loss Optical filters Equalization enhanced phase noise optical fiber communication phase noise quadrature amplitude modulation raised cosine filter

来源：评论

学校读者我要写书评

暂无评论

Investigation of a Modified Flux-Coupling-Type SFCL for Low-Voltage Ride-Through Fulfillment of a Virtual Synchronous Generator

引用

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 2020年第4期30卷 1-6页

作者： Chen, Lei Li, Guocheng Chen, Hongkun Ding, Meng Zhang, Xuyang Li, Yanhong Xu, Ying Ren, Li Tang, Yuejin Wuhan Univ Sch Elect Engn & Automat Wuhan 430072 Peoples R China Guangzhou Power Supply Co Ltd Guangzhou 510620 Peoples R China China Southern Power Grid Co Ltd Guangzhou 510620 Peoples R China Huazhong Univ Sci & Technol Wuhan 430074 Peoples R China

To solve the low-voltage ride-through (LVRT) issue of a virtual synchronous generator (VSG) under severe grid fault, our research group proposes to use a modified flux-coupling-type superconducting fault current limiter (SFCL). In this study, the configuration structure of the VSG with the SFCL at the point of common coupling (PCC) is designed. The fault analytical circuit of the VSG is presented, and the functions of the SFCL are stated from the aspects of current restraint, voltage compensation, and energy dissipation. Using MATLAB/Simulink, symmetrical and asymmetrical faults are both simulated to assess the transient behaviors of the VSG, and the SFCL parameters are changed to clarify the quantitative effects. From the comparison results, the SFCL parameters are properly determined to provide favorable performance. The SFCL can visibly decrease the fault current of each phase within the permissible level, and facilitate the VSG to have a preferable voltage profile. Furthermore, the SFCL can positively stabilize the VSG by enhancing the power delivery, mitigating the frequency fluctuation and consuming the excess energy. A satisfactory LVRT operation is gained, and the efficacy of the SFCL on reinforcing the VSG robustness is validated.

关键词： Low-voltage ride-through superconducting fault current limiter transient analysis virtual synchronous generator

来源：评论

学校读者我要写书评

暂无评论

Quasi-distributed optical fiber sensing for the coupled vibration analysis of high-speed train-bridge coupled system under earthquakes

引用

SENSORS AND ACTUATORS A-PHYSICAL 2024年 374卷

作者： Xiang, Ping Xie, Xiaonan Zhang, Xuebing Wu, Han Chen, Zhizhan Wang, Li Liu, Xiaochun Yang, Delei Wang, Huaping Cent South Univ Sch Civil Engn Changsha 410075 Hunan Peoples R China Xiangtan Univ Coll Civil Engn Xiangtan 411105 Hunan Peoples R China Univ Huanghuai Dept Bldg Engn 6 Kaiyuan Rd Zhumadian Henan Peoples R China Lanzhou Univ Sch Civil Engn & Mech Lanzhou Peoples R China City Univ Hong Kong Depsrtment Civil & Architectural Engn Hong Kong Peoples R China

Due to the extensive construction of high-speed rail lines passing through seismically active areas, the possibility of a sudden earthquake occurring during train operation is very high. Additionally, the earthquake will intensify the dynamic response of trains and bridges, causing serious bridge damage. In this work, the dynamic response behavior of the bridge structures in the coupled train-bridge system under the earthquake is investigated based on the 4-table shaking table system. Shaking table experiments are also conducted on a high-speed railroad model of simple-supported girder bridge at a scale of 1/10 with the simulated layers of China Railway Track System type II (CRTS II) ballastless track slabs. The strain responses of various components, including rails, track plates, base plates, and beams, were measured on the bridge using quasi-distributed fiber optic gratings, both with and without seismic actions. Additionally, the seismic isolation characteristics of the fasteners and the CA mortar layer were investigated. The dynamic performance of the coupled train-bridge system under earthquakes was studied in both the time and frequency domains.

关键词： Train-bridge system Earthquake Dynamics performances Frequency Quasi-distributed fiber Bragg grating

来源：评论

学校读者我要写书评

暂无评论

Joint exploitation potential of offshore wind and wave energy along the south and southeast coasts of China

引用

ENERGY 2022年 249卷 123710-123710页

作者： Wen, Yi Kamranzad, Bahareh Lin, Pengzhi Sichuan Univ Coll Architecture & Environm South Sect 124 Yihuan Rd Chengdu 610065 Peoples R China Kyoto Univ Hakubi Ctr Adv Res Yoshida HonmachiSakyo-ku Kyoto 6068501 Japan Kyoto Univ Grad Sch Adv Integrated Studies Human Survivabil G Yoshida-Nakaadachi 1 Sakyo-ku Kyoto 6068306 Japan Imperial Coll London Fac Nat Sci Dept Phys London SW7 2AZ England Sichuan Univ State Key Lab Hydraul & Mt River Engn South Sect 124 Yihuan Rd Chengdu 610065 Peoples R China

There is an increasing interest in co-exploiting marine energies of various types, as it can reduce grid connection and maintenance costs and enhance electricity production. A threefold objective of this work is as follows: i) investigate offshore wind and wave energy potential, complementarity & synergy, and correlation between the two resources in southern China's coastal region using long-term data;ii) analyze the benefits of wind-wave joint exploitation considering specific offshore wind turbine (OWT) and wave energy converter (WEC);and iii) propose a new index to determine the suitability for co developing wind-wave projects. The results show that the Beibu Gulf and Taiwan Strait experience the highest correlation between the two resources, in contrast to the Zhejiang coast that exhibits the lowest one. On the other hand, the east waters of Taiwan and Zhejiang coast have the highest synergy. Moreover, quantitative and qualitative analysis shows that the combined device generates less variable power output and zero production in the areas with low correlation and high synergy than the OWT/WEC operating alone. The suggested best sites for future joint exploitation are along the Zhejiang coast, with the potential of generating nearly 40 GWh/year per combined device of SWT-6.0-154 and 6 MW Wave Dargon.(c) 2022 Elsevier Ltd. All rights reserved.

关键词： Offshore wind Wave energy Southern China Correlation Complementarity and synergy

来源：评论

学校读者我要写书评

暂无评论

Linear study of magnetic sensing for MTJ devices based on CoFeB/MgO/ CoFeB magnetic films with large aspect ratio

引用

SURFACE & COATINGS technology 2025年 498卷

作者： Liu, Xing Song, Qiuming Yang, Jiahao Jia, Yuan Chen, Yulong Tian, Jinpeng Zhang, Zhixing Zhang, Wenwei Shenzhen Technol Univ Sino German Coll Intelligent Mfg Industrializat Ctr Micro & Nano ICs & Devices Shenzhen 518118 Peoples R China Guangdong Univ Technol State Key Lab Precis Elect Mfg Technol & Equipment Guangzhou 510000 Peoples R China

Since the discovery of the tunneling magnetoresistance (TMR) effect in magnetic tunnel junctions (MTJs), magnetic field sensors based on MTJ have gained much attention in the last decades due to their high sensitivity, low cost, and small size. This kind of sensor has a wide range of applications in the automotive industry and consumer electronics. With its high sensitivity and detection accuracy, it has the potential to detect weak magnetic fields. In this paper, a series of top-pinned MTJ was deposited and fabricated into magnetic devices by photolithography and etching, with the size of the MTJ in the range of 10-60 mu m2. We studied the interaction mechanism and the variation of magnetization directions in MTJ films. The properties of MTJ with different aspect ratio, annealing methods and free layer's thickness was measured. The MTJ devices firstly show a low hysteresis linear output in only large aspect ratio under single-step short-axis annealing. By the two-step annealing method, the dependence of MTJ's linear output on aspect ratio was successfully reduced. With appropriate free layer thicknesses and optimization of the two-step annealing method, the MTJ achieves a linear output with a sensitivity of 1.06 %/Oe and nearly zero hysteresis. These results are valuable for linearized sensing of MTJs based on shape anisotropy and for high-sensitivity magnetic field sensing applications.

关键词： Magnetic material Magnetic tunnel junction Magnetic sensing Shape anisotropy

来源：评论

学校读者我要写书评

暂无评论

An Intelligent Virtual Standard Patient for Medical Students Training Based on Oral Knowledge Graph

引用

IEEE TRANSACTIONS ON MULTIMEDIA 2023年 25卷 6132-6145页

作者： Song, Wenfeng Hou, Xia Li, Shuai Chen, Chenglizhao Gao, Danyang Wang, Xian'e Sun, Yuzhe Hou, Jianxia Hao, Aimin Beijing Informat Sci & Technol Univ Comp Sch Beijing 100101 Peoples R China Beihang Univ State Key Lab Virtual Real Technol & Syst Beijing 100191 Peoples R China Peng Cheng Lab Shenzhen 518055 Peoples R China China Univ Petr East China Coll Comp Sci & Technol Qingdao 266580 Peoples R China Peking Univ Dept Periodontol Sch & Hosp Stomatol Beijing Peoples R China

Virtual standard patient (VSP) is in high demand for medical students' diagnosis ability training in an efficient manner. Different from the traditional conversation system in medical dialogue generation, VSP needs a novel conversation paradigm to act as the patient instead of the doctor. However, existing conversation techniques still have limited ability in terms of generation of symptoms exhibited by patients with the personalized and knowledge-centered expressions. To alleviate these problems, we propose to construct a novel oral knowledge graph, which sufficiently provides medical clues of the certain disease. Accordingly, the VSP could accurately interact with the dentists for their underlying intention and express the symptoms characters in a natural style. To efficiently retrieve the related disease clues, the symptoms descriptions of the oral diseases are encoded into the oral knowledge graph, which could well organize the disease-centered symptom entities and speaking styles. Moreover, to transfer the common sense knowledge from existing large scale of medical knowledge graph to the specific oral knowledge graph, a coupled pre-trained Bert models is further designed to learn the related medical knowledge from coarse-level to fine-level hierarchically. Finally, a series of well-designed personalized templates are proposed to generate plausible and realistic answers in condition of the certain disease. We also conduct extensive user studies to demonstrate that the VSP satisfies the medical students' diagnosis practice requirement in terms of naturalness, realism, and topic relevance.

关键词： Intelligent Training Oral Knowledge Graph Virtual Standard Patient

来源：评论

学校读者我要写书评

暂无评论

Phase formation and elemental transport in the vacuum diffusion bonding between CoCrFe 0.2 NiMn and CoCrFe 16 NiMn multicomponent alloys

引用

VACUUM 2024年 226卷

作者： Li, Fangjie Zhu, Zongxin Hu, Han Yang, Dongye Liu, Min Shen, Qin Zheng, Jun Xiong, Changhong Zhang, Yan Shanghai Univ Engn Sci Sch Mat Sci & Engn 333 Longteng Rd Shanghai 201602 Peoples R China Shanghai Inst Technol Sch Mat Sci & Engn 100 Haiquan Rd Shanghai 201418 Peoples R China Shanghai Univ Engn Sci Sch Mech & Automot Engn 333 Longteng Rd Shanghai 201602 Peoples R China Anhui Univ Technol Key Lab Green Fabricat & Surface Technol Adv Met M Minist Educ Maanshan 243002 Peoples R China

To efficiently explore the influence of Fe content on the phase stability of the multicomponent CoCrFexNiMn (hereafter abbreviated as Fex) alloys. A diffusion layer with continuous, concentration gradient of Fe element is created based on diffusion couple technique. The microstructure and element distribution of the diffusion bonded layer between Fe0.2 and Fe alloys are analyzed. A new layer of FCC and HCP solid solution phases generates in the diffusion zone, which is consistent with the prediction of parametric approach and phase diagram calculation. As diffusion proceeds, the FCC phase is transformed from the BCC phase with the decreasing of Fe content and the HCP phase might be the transitional phase during this transition. The newly formed FCC and HCP phases are shown specific orientation relationships with the BCC phase. Elemental analysis indicated that the diffusion rate of the alloy components in the FCC phase is Cr > Mn > Co > Ni. The large concentration gradient in the diffuse interface and grain boundaries diffusion of BCC phase promoted the Fe diffusion, causing the BCC phase to transform into FCC phase.

关键词： High entropy alloy Diffusion bonding Phase transformation Microstructure

来源：评论

学校读者我要写书评

暂无评论

Modeling and Cross-Timescale Mechanism Analysis of Voltage Control Impact on Electromechanical Dynamics of VSG-Controlled DFIG-Based WT

引用

IEEE Transactions on Energy Conversion 2024年

作者： Cai, Shiyu Li, Yingbiao Wang, Wei Zhan, Meng Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Wuhan430074 China

With the development of doubly fed induction generator (DFIG)-based wind turbines (WTs), the application of virtual synchronous generation (VSG) concepts in DFIG control has gained attention for enhancing grid stability. The VSG-controlled DFIG system, characterized by its multiple timescale energy storage elements and control loops, presents a complex dynamic behavior of multiple timescales and there are interactions between different timescales. However, existing research mostly focuses on modeling and stability analysis of a single timescale, neglecting the cross-timescale effects. This paper presents a dynamic modeling methodology for VSG-controlled DFIG-based WTs to analyze the cross-timescale impact of voltage control on electromechanical dynamics. Firstly, cross-timescale phenomena and laws of the impact are revealed. An excitation and response dynamical model of VSG-controlled DFIG is proposed, which can provide a physical comprehension of the formation mechanisms behind cross-timescale phenomena within DFIG. Additionally, the analysis of the impact of voltage control on electromechanical dynamics is performed using the damping torque. Finally, the analyses of cross-timescale mechanisms are validated through time-domain simulations. © 2024 IEEE.

关键词： Asynchronous generators

来源：评论

学校读者我要写书评

暂无评论

The formation mechanism of aqueous hydrogen peroxide in a plasma-liquid system with liquid as the anode

引用

EUROPEAN PHYSICAL JOURNAL D 2020年第4期74卷 1-7页

作者： Lin, Jiao He, Xinyi Chen, Qiang Xiong, Qing Li, Junshuai Wang, Xin Chen, Guolong Liu, Qing Huo Ostrikov, Kostya (Ken) Xiamen Univ Inst Electromagnet & Acoust Fujian Prov Key Lab Plasma & Magnet Resonance Dept Elect Sci Xiamen 361005 Fujian Peoples R China Chongqing Univ State Key Lab Power Transmiss Equipment & Syst Se Chongqing 400044 Peoples R China Lanzhou Univ Minist Educ Key Lab Special Funct Mat & Struct Design Lanzhou 730000 Gansu Peoples R China Lanzhou Univ Sch Phys Sci & Technol Lanzhou 730000 Gansu Peoples R China Duke Univ Dept Elect & Comp Engn Durham NC 27708 USA Queensland Univ Technol Sch Chem & Phys Brisbane Qld 4000 Australia CSIRO QUT Joint Sustainable Proc & Devices Lab POB 218 Lindfield NSW 2070 Australia

We investigate the formation of aqueous hydrogen peroxide (H2O2aq) in a DC discharge plasma-liquid system with liquid as the anode. The theoretical analysis and experimental results show that the H2O2aq formation process is mostly controlled by the aqueous electron-induced reactions in the liquid zone directly affected by the plasma. It is shown that the low H2O2aq yield in this system is caused by quenching the dissolved OH radicals through aqueous electrons and alkalization in the plasma-directly-affected liquid zone.

关键词： Plasma Physics

来源：评论

学校读者我要写书评

暂无评论

Multi-Interfacial Heterostructure Design of Carbon Fiber/Silicone Rubber-Oriented Composites for Microwave Absorption and Thermal Management

引用

advanced FUNCTIONAL MATERIALS 2024年第51期34卷

作者： Liu, Yijie Zhou, Jintang Ning, Zuolong Huang, Hexia Cheng, Zhenyu Duan, Lvtong Wang, Yucheng Tao, Xuewei Liu, Peijiang Ma, Yao Yao, Zhengjun Nanjing Univ Aeronaut & Astronaut Coll Mat & Technol Nanjing 211100 Peoples R China Nanjing Univ Aeronaut & Astronaut Key Lab Mat Preparat & Protect Harsh Environm Nanjing 211100 Peoples R China Nanjing Univ Aeronaut & Astronaut Coll Energy & Power Engn Nanjing 210016 Peoples R China Nanjing Inst Technol Jiangsu Key Lab Adv Struct Mat & Applicat Technol Nanjing 211100 Peoples R China Minist Ind & Informat Technol Sci & Technol Reliabil Phys & Applicat Technol Ele Elect Res Inst 5 Guangzhou 511370 Guangdong Peoples R China Army Engn Univ Natl Key Lab Electromagnet Environm Effects & Elec Nanjing 210007 Peoples R China

In order to ensure the operation and longevity of electronic devices, the design of multifunctional composites integrating microwave absorption (MA) and thermal conduction has become the key to solving the problem. However, the superior MA properties and thermal conductivity are usually incompatible in the blend system. In this study, a modified carbon fiber/silicone rubber-oriented structure is designed based on the multiscale design concept of heterostructures with multiple interfaces. The forward deposition-reverse growth mechanism is utilized at the microscopic level to construct multi-interfacial heterogeneous structures on the surface of 1D carbon fibers (CFs). The magneto-electric coupling network of the multi-interfacial heterostructure induces interfacial polarization and enhances MA properties and heat transfer. Subsequently, the structural design of the modified CFs is carried out on a macroscopic scale using the ice template method. The directionally aligned modified CFs/silicone rubber aerogel composites are obtained by backfilling with silicone rubber (SR). The samples achieved an effective absorption bandwidth of 4.41 GHz and a maximum reflection loss of -42.29 dB with ultra-thin thickness (1.3 mm). The thermal conductivity of the sample is improved to 200% compared to pure silicone rubber. The composites with directional alignment have promising applications in lightweight and flexible electronic packaging. The modified carbon fiber/silicone rubber-oriented structure is designed based on the multiscale design concept of heterostructures with multiple interfaces. The sample has achieved an effective absorption bandwidth of 4.41 GHz at 1.3 mm ultra-thin thickness and improved thermal conductivity. The composites with directional alignment have promising applications in lightweight and flexible electronic packaging. image

关键词： directionally aligned aerogel microwave absorption/thermal conductivity composites multifacial heterostructure multifunctions

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：