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Reducing Cyclic Prefix Overhead Based on Symbol Repetition in NB-IoT-Based Maritime Communication

China Communications 2022年第9期19卷 1-9页

作者： Tian Xiang Daiming Qu Faquan Zhang Dejin Kong School of Electronic and Electrical Engineering Wuhan Textile UniversityWuhan 430200China Sthe State Key Laboratory of New Textile Materials and Advanced Processing Technologies Wuhan Textile UniversityWuhan 430200China School of Electronic Information and Communication Huazhong University of Science and TechnologyWuhan 430074China

With the increasing maritime activities,a great demand of wide-area maritime digital data services is ***,Narrowband Internet of Things(NB-IoT)that can provide wide coverage has been expected as an application for maritime communication networks(MCNS).In this paper,we aim to enhance the spectral efficiency in NB-IoT by reducing the cyclic prefix(CP)overhead in random access signal without causing *** key point of the proposed scheme is the symbols transmitted for multiple times repeatedly in ***,all CP are removed and multi-path fading effect is eliminated by using a repeated symbol to cover the disturbed symbol to construct a circular convolution structure of the channel with the same effect as adding *** addition,a single-tap equalization is still *** validate the effectiveness of the proposed scheme,simulation results are carried out with respect to the bit error ratio(BER).

关键词： NB-IoT narrowband physical random access channel cyclic prefix spectral efficiency

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Durable and Wearable Self-powered Temperature Sensor Based on Self-healing Thermoelectric Fiber by Coaxial Wet Spinning Strategy for Fire Safety of Firefighting Clothing

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advanced Fiber materials 2024年第5期6卷 1387-1401页

作者： Qing Jiang Yuhang Wan Yi Qin Xueru Qu Mi Zhou Siqi Huo Xiaochun Wang Zhicai Yu Hualing He State Key Laboratory of New Textile Materials and Advanced Processing Technologies Hubei Key Laboratory of Biomass Fibers and Eco-dyeing&FinishingSchool of Textile Science and EngineeringWuhan Textile UniversityWuhan 430200China Centre for Future Materials University of Southern QueenslandSpringfield Central 4300Australia School of Materials Design and Engineering Beijing Institute of Fashion TechnologyBeijing 100029China

Self-healable electronics with self-recoverable mechanical properties show a lot of potential in improving the reliability and durability of wearable electronic devices,but it is still ***,a self-healing core-sheath thermoelectric(TE)fiber-based temperature sensor was continuously fabricated by coaxial wet-spinning strategy,whose core layer and sheath layer are,respectively,pure Ti_(3)C_(2)T_(x)MXene and self-healing silk sericin(SS)/oxide sodium alginate(OSA)*** prepared SS/OSA@MXene core-sheath TE fiber exhibits accurate temperature-sensing at 200-400℃based on a linear relationship between TE voltage and temperature *** core-sheath TE fiber that can be integrated into firefighting clothing and timely alert firefighters to evacuate from the fire before the protective clothing becomes *** exposed to flames,SS/OSA@MXene can rapidly trigger a high-temperature warning voltage of 3.36 mV within 1.17 s and exhibit reversible high-temperature alarm *** addition,the fractured SS/OSA@MXene can restore up to 89.12%of its original strain limit at room temperature because of the robust yet reversible dynamic covalent bonds between SS and *** this study,an ingenious strategy for developing a durable and wearable TE fiber-based self-powered temperature sensor was *** strategy has promising application prospects in real-time temperature detection of firefighting clothing to ensure the safety of firefighters operating on a fire scene.

关键词： Core-sheath thermoelectric fiber Self-powered sensor High-temperature warning Self-healing Coaxial wet spinning

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Microstructure and elevated-temperature mechanical properties of dispersoid-strengthened Al-Mg-Si-Mn alloys produced by twin roll casting

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Progress in Natural Science:materials International 2021年第5期31卷 705-713页

作者： Yong Li Haiyao Wang Xiaoming Qian Zhaodong Wang Guangming Xu Jiadong Li State Key Laboratory of Rolling and Automation Northeastern University Guangxi Advanced Aluminum Processing Innovation Center Co.LTD National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan University Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern University

The microstructure and elevated-temperature mechanical properties of dispersoid-strengthened Al-Mg-Si-Mn alloys produced by twin roll casting(TRC) and conventional mold casting(MC) were studied. A specific heat treatment at 430℃ for 6 h was applied, followed by rolling. Tensile tests were carried out at 300℃. The results show that in the as-cast microstructures, equiaxed grains formed in the MC sample while elongated grains with substructures formed in the TRC sample. The eutectics in the TRC sample were much finer than those in the MC sample. Upon heat treatment, large numbers of α-Al(Fe, Mn)Si dispersoids precipitated, and the TRC sample had a greater number density of dispersoids than those in the MC sample. During the tensile test after rolling, the TRC samples exhibited higher strength than the MC samples, which resulted from the combination of the strengthening effect of the stronger dispersoids and the greater substructure hardening effect in the TRC sample; the TRC sample exhibited better ductility due to its finer initial eutectic than that in the MC sample, which depressed the stress concentration and delayed the occurrence of microcracks and fracture in the TRC sample.

关键词： Aluminum alloy Twin-roll casting (TRC) α-Al(Fe Mn)Si dispersoids Elevated-temperature

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Engineering single atomic ruthenium on defective nickel vanadium layered double hydroxide for highly efficient hydrogen evolution

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Nano Research 2023年第4期16卷 4612-4619页

作者： Xiaoyu Chen Jiawei Wan Meng Zheng Jin Wang Qinghua Zhang Lin Gu Lirong Zheng Xianzhu Fu Ranbo Yu College of Materials Science and Engineering Shenzhen UniversityShenzhen 518071China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Department of Physical Chemistry School of Metallurgical and Ecological EngineeringUniversity of Science and Technology Beijing InstitutionBeijing 100083China State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Key Laboratory of Advanced Material Processing&Mold Ministry of EducationZhengzhou UniversityZhengzhou 450002China

Fabricating single-atom catalysts(SACs)with high catalytic activity as well as great stability is a big ***,we propose a precise synthesis strategy to stabilize single atomic ruthenium through regulating vanadium defects of nickel vanadium layered double hydroxides(NiV-LDH)ultrathin nanoribbons ***,the isolated atomically Ru doped NiV-LDH ultrathin nanoribbons(NiVRu-R)were successfully fabricated with a super-high Ru load of 12.8 wt.%.X-ray absorption spectrum(XAS)characterization further confirmed atomic dispersion of *** catalysts for electrocatalytic hydrogen evolution reaction(HER)in alkaline media,the NiVRu-R demonstrated superior catalytic properties to the commercial Pt/***,it maintained exceptional stability even after 5,000 cyclic voltammetry ***-situ XAS and density functional theory(DFT)calculations prove that the Ru atomic sites are stabilized on supports through forming the Ru-O-V structure,which also help promote the catalytic properties through reducing the energy barrier on atomic Ru catalytic sites.

关键词： hydrogen evolution reaction layered double hydroxide ruthenium atomic site ultrathin nanoribbons

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Study on Time-Domain Electromagnetic Response of Coal Seams During Spontaneous Combustion

Study on Time-Domain Electromagnetic Response of Coal Seams ...

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2023 International Applied Computational Electromagnetics Society Symposium, ACES-China 2023

作者： Cao, Le Yuan, Hao-Wei Wei, Yi-Wen Liu, Xu-Qing College of Electric and Control Engineering Xi'an University of Science and Technology Xi'an China School of Physics Xidian University Xi'an China Northwestern Polytechnical University Xi'an State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal Materials China

ISBN: (纸本)9781733509657

In this paper, the temperature-frequency-electricity parameter relationship is firstly established, and then the reflection coefficient of the three-layer coal medium is calculated based on the generalized propagation matrix method, and then the variation of the reflected waves of the coal seam medium with the coal temperature is obtained by Fourier transform. The results show that the peak value of the reflected wave decreases first with temperature, then flattens out, and finally increases. The characteristic temperatures of different coal types in the process of spontaneous combustion are given in this paper, which provides a basis for the detection and early warning of coal spontaneous combustion. © 2023 Applied Computational Electromagnetics Society (ACES).

关键词： Spontaneous combustion

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Interwoven scaffolded porous titanium oxide nanocubes/carbon nanotubes framework for high-performance sodium-ion battery

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Journal of Energy Chemistry 2021年第8期30卷 38-46,I0002页

作者： Wen-Bei Yu Wen-Da Dong Chao-Fan Li Nasiruddin Macadam Jiu-Xiang Yang Guo-Bin Zhang Zhi-Yi Hu Tien-Chun Wu Yu Li Tawfique Hasan Li-Hua Chen Li-Qiang Mai Bao-Lian Su State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Cambridge Graphene Centre University of Cambridge9 JJ Thomson AvenueCB30FA CambridgeUnited Kingdom Nanostructure Research Centre(NRC) Wuhan University of TechnologyWuhan 430070China Laboratory of Inorganic Materials Chemistry(CMI) University of Namur61 rue de Bruxelles5000 NamurBelgium

Supercapacitor-like Na-ion batteries have attracted much attention due to the high energy density of batteries and power density of *** dioxide(TiO_(2)),is a promising anode *** performance is however seriously hindered by its low electrical conductivity and the sluggish diffusion of sodium ions(Na^(+))in the TiO_(2)***,this work combines porous TiO_(2)nanocubes with carbon nanotubes(CNTs)to enhance the electrical conductivity and accelerate Na^(+)diffusivity for Na-ion batteries(NIBs).In this composite,an interwoven scaffolded TiO_(2)/CNTs framework is formed to provide abundant channels and shorter diffusion pathways for electrons and *** in-situ X-ray diffraction and cyclic voltammetry confirm the low strain and superior transport kinetics in Na^(+)intercalation/extraction *** addition,the chemically bonded TiO_(2)/CNTs hybrid provides a more feasible channel for Na^(+)insertion/extraction with a much lower energy ***,the TiO_(2)/CNTs composite exhibits excellent electrochemical performance with a capacity of 223.4 m Ah g^(-1)at 1 C and a capacity of 142.8 m Ah g^(-1)at 10 C(3.35 A g^(-1)).The work here reveals that the combination of active materials with CNTs can largely improve the utilization efficiency and enhance their sodium storage.

关键词： Supercapacitor-like Interwoven scaffold Na-ion battery TiO_(2) Carbon nanotubes

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Zero-Valent Iron Supported by Dendritic Mesoporous Silica Nanoparticles to Purify Dye Wastewater

SSRN

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SSRN 2023年

作者： Chang, Baisong Dong, Kangfeng Wu, Shaolong Sun, Taolei State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China School of Chemistry Chemical Engineering and Life Science Wuhan University of Technology Wuhan430070 China

The presence of different types of organic dyes in water stream will clearly give rise to unexceptional side effects on living organisms. Emerging physical or chemical methods have been developed for the treatment of dye-involving water, but the exploration for adequate design strategy and technique available is still ongoing. Here, the zero-valent iron (ZVI) was prepared by a liquid phase sodium borohydride reduction approach and then integrated with dendritic mesoporous silica nanoparticle (DMSN) to construct the Janus magnetic adsorbent (denoted as ZVI-DMSN), which could be employed to purify dye wastewater. The structure, magnetic properties and dye adsorption results of ZVI-DMSN were systematically investigated. The ZVI component can enable efficient solid-liquid separation through magnetic separation route, and, more importantly, provided additional binding sites for adsorption process to increase the adsorption capacity. The thermodynamic analysis of adsorption indicated that the adsorption of typical organic dyes was an irreversible, spontaneous and endothermic process. Moreover, ZVI-DMSN adsorbent was recyclable, showing a regeneration efficiency of more than 80% after 5 cycles. We believe that ZVI-DMSN, as an inexpensive adsorbent material with excellent adsorption properties, e.g., short time, high efficiency and large capacity, will host vast potential for removal of dyes in water bodies. © 2023, The Authors. All rights reserved.

关键词： Wastewater treatment

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Bimetal-organic framework-derived carbon nanocubes with 3D hierarchical pores as highly efficient oxygen reduction reaction electrocatalysts for microbial fuel cells

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Science China materials 2021年第12期64卷 2926-2937页

作者： Neng Chen Zihan Meng Rui Wang Shichang Cai Weibin Guo Haolin Tang Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Xianhu Hydrogen ValleyFoshan 528200China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Noble metal-free and highly efficient electrocatalytic materials with hierarchically porous structures continue to be studied for the oxygen reduction reaction(ORR) in microbial fuel cells(MFCs). We report bimetal-organic framework(bi-MOF)-derived nanocubic Swiss cheese-like carbons with a novel three-dimensional hierarchically porous structure(3D Co-N-C) prepared by utilizing cetyltrimethylammonium bromide(CTAB) as a structure-directing agent to control the formation of a nanocubic skeleton, and silica spheres as a template to form a mesoporous structure. The elemental composition and chemical morphology of this material can be tuned through the Zn/Co ratio to optimize its ORR catalytic activity. The optimized 3D Co-N-C displays excellent ORR catalytic performance(half-wave potential as high as 0.754 V vs. reversible hydrogen electrode and diffusion-limiting current density of 5.576 mA cm^(-2)) in 0.01 mol L^(-1) phosphate-buffered saline(PBS electrolyte),showing it can compete with the commercial 20 wt% Pt/C catalysts. The catalytic capability and long-term durability of 3D Co-N-C as an air-filled cathode electrocatalyst in an MFC device are tested, showing that the 3D CoNC-MFC can reach a high power density of 1257 mW m^(-2) and provide a competitive voltage during a periodic feeding operation for 192 h;these values are much higher than those of the Pt/C-MFC.

关键词： Co-N-doped carbon structure-oriented approach 3D hierarchically porous nanocubes oxygen reduction reaction microbial fuel cells

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Electrical Properties and Degradation Behavior of Bnt-Bt-Ln Ceramics

SSRN

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SSRN 2023年

作者： Xu, Qi Yan, Xuerui He, Xin Dong, Shengde Ma, Luxiang Hai, Chunxi Zhou, Yuan Liu, Hanxing College of Materials and Chemistry & Chemical Engineering Chengdu University of Technology Chengdu610059 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Material Science and Engineering Wuhan University of Technology Wuhan430070 China

Dielectric capacitors are widely used in pulse power systems, electric vehicles, aerospace and defense technology as critical electronic components. Due to the miniaturization and diversification of electronic components, higher requirements are put on the electrical properties and the service life of dielectric capacitors. In this paper, the phase structure, microstructure, dielectric, ferroelectric and failure behavior of (1-x)(Bi0.5Na0.5TiO3-BaTiO3)-xLiNbO3 (BNT-BT-LN, x = 0.01, 0.03, 0.05, 0.07, 0.10) lead-free ceramics were investigated. All the samples exhibited perovskite phase with no secondary impurity. With increasing LiNbO3 concentration, the average grain size gradually increases from 0.78 μm to 1.75 μm. For the composition x = 0.07, the temperature coefficient of capacitance (TCC150°C) was lower than 15% in the range of 35 °C - 400 °C with moderate permittivity (Εr 150 °C = 2050) and low dielectric loss (tanδ150 °C = 0.005). The RC constant is above 19.3 s up to 245 °C. Through Highly Accelerated Life Test (HALT), the mean time to failure (TTF) empirical formula for BNT-BT-LN dielectrics is established. It indicates that the degradation of the insulation resistance process is caused by the electromigration of oxygen vacancies and the TTF is predicted to reach 4.67×106 h at 7 kV/mm and room temperature. © 2023, The Authors. All rights reserved.

关键词： Lithium compounds

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High-temperature thermal stability of C/C−ZrC−SiC composites via region labeling method

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Transactions of Nonferrous Metals Society of China 2022年第10期32卷 3349-3361页

作者： Zheng PENG Chun-mao MIAO Wei SUN Yong-long XU Hai-kun CHEN Yu-feng LIU Hong-bo ZHANG Xiang XIONG State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Science and Technology on Advanced Functional Composites Laboratory Aerospace Research Institute of Materials and Processing TechnologyBeijing 100089China

To investigate the thermal stability of ceramic-matrix composites,three kinds of C/C−ZrC−SiC composites with different Zr/Si molar ratios were synthesized by reactive melt *** region labeling method,the high-temperature thermal stability of the composites was systematically studied by changing the temperature and holding time of thermal *** show that the mass loss rate of low Si composites has a growth trend with increasing temperature,and a crystal transformation from β-SiC toα-SiC occurs in the *** the calibrated area,SiC phase experiences Ostwald ripening and volume change with location migration,while ZrC phase experiences a re-sintering process with ***,it is found that increasing temperature has a more obvious effect on the thermal stability than extending holding time,which is mainly attributed to the faster diffusion rate of atoms.

关键词： thermal stability ceramic-matrix composites reactive melt infiltration high-temperature thermal treatment region labeling method

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