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NS codoped carbon nanorods as anode materials for high-performance lithium and sodium ion batteries

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Journal of Energy Chemistry 2018年第1期27卷 203-208页

作者： Ajuan Hu Song Jin Zhenzhen Du Hongchang Jin Hengxing Ji department of Materials science and engineering CAS Key Laboratory of Materials for Energy Conversion iChEM University of Science and Technology of China

NS codoped carbon nanorods（NS-CNRs） were prepared using crab shell as template and polyphenylene sulfide（PPS） as both the C and S precursor, followed by carbonization in NH_3. The as-obtained NS-CNRs had a diameter of ~50 nm, length of several micrometers, and N and S contents of 12.5 at.% and 3.7 at.%,respectively, which can serve as anodes for both lithium-ion batteries（LIBs） and sodium ion batteries（SIBs）. When serving as an anode of LIB, the NS-CNRs delivered gravimetric capacities of 2154 mAh g^（-1）at current densities of 0.1 A g^（-1）and 625 mAh g^（-1）at current densities of 5.0 A g^（-1）for 1000 *** serving as an anode of SIB, the NS-CNRs delivered gravimetric capacities of 303 mAh g^（-1）at current densities of 0.1 A g^（-1）and 230 mAh g^（-1）at current densities of 1.0 A g^（-1）for 3000 cycles. The excellent electrochemical performance of NS-CNRs could be ascribed to the one-dimensional nanometer structure and high level of heteroatom doping. We expect that the obtained NS-CNRs would benefit for the future development of the doped carbon materials for lithium ion batteries and other extended applications such as supercapacitor, catalyst and hydrogen storage.

关键词： NS codoped carbon Crab shell template Lithium ion batteries Sodium ion batteries

Deep learning method for super-resolution reconstruction of the spatio-temporal flow field

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Advances in Aerodynamics 2023年第1期5卷 387-402页

作者： Kairui Bao Xiaoya Zhang Wei Peng Wen Yao College of aerospace science and engineering National University of Defense TechnologyChangsha 410073China Defense Innovation Institute Chinese Academy of Military ScienceBeijing 100071China

The high-resolution(HR)spatio-temporal flow field plays a decisive role in describing the details of the flow *** the acquisition of the HR flow field,traditional direct numerical simulation(DNS)and other methods face a seriously high computational *** address this deficiency,we propose a novel multi-scale temporal path UNet(MST-UNet)model to reconstruct temporal and spatial HR flow fields from low-resolu-tion(LR)flow field *** from the previous super-resolution(SR)model,which only takes advantage of LR flow field data at instantaneous(SLR)or in a time-series(MTLR),MST-UNet introduces multi-scale information in both time and ***-UNet takes the LR data at the current frame and the predicted HR result at the previous moment as the model input to complete the spatial SR *** this basis,a temporal model is introduced as the inbetweening model to obtain HR flow field data in space and time to complete spatio-temporal SR ***,the proposed model is validated by the spatio-temporal SR task of the flow field around two-dimen-sional *** results show that the outcome of the MST-UNet model in spatial SR tasks is much better than those of SLR and MTLR,which can greatly improve prediction *** addition,for the spatio-temporal SR task,the spatio-temporal HR flow field predicted by the MST-UNet model has higher accuracy either.

关键词： Super-resolution Flow field UNet Deep learning

Facet and dimensionality control of Pt nanostructures for efficient oxygen reduction and methanol oxidation electrocatalysts

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Nano Research 2016年第9期9卷 2811-2821页

作者： Lingzheng Bu Yonggang Feng Jianlin Yao Shaojun Guo Jun Guo Xiaoqing Huang College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China department of Materials science and engineering & department of Energy and Resources engineering College of EngineeringPeking UniversityBeijing 100871China Testing & Analysis Center Soochow UniversitySuzhou 215123China

The control of the size, composition, and shape of platinum nanocrystals has attracted much attention recently, mostly due to their unique properties and related catalytic functionalities. However, the realization of platinum nanocrystals with controlled exposed facets and dimensionality remains a significant challenge. Herein, we show an efficient synthetic strategy to selectively prepare highly controllable platinum nanocrystals with distinct dimensionalities from onedimensional nanowires to zero-dimensional octahedra. Although the synthesis of platinum nanowires has been reported multiple times, the synthetic approach reported herein is much more novel and robust and ultimately results in high yields of high-quality platinum nanowires. Such dimensionality tuning on {111} facet dominated platinum nanocrystals allows us to firstly investigate the effect of the number of edges/corners on the electrocatalytic properties. Our results show that the synthesized platinum nanocrystals exhibit very interesting dimensionality-dependent electrocatalytic activity towards both the oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR), in which one-dimensional platinum nanowires with minimized edges/corners show enhanced electrocatalytic activities with respect to zero-dimensional platinum octahedra. Our dimensionality tuning also provides Pt nanowires with superior durability for the oxygen reduction reaction with negligible activity decay over the course of 30,000 potential sweeps. The present work highlights that the {111} facet bound platinum nanowires with minimized edges/corners are indeed promising candidates as electrocatalysts with excellent activity and superior durability. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

关键词： platinum nanowires octahedra {111} facet oxygen reduction reaction methanol oxidation reaction

Multiple rotation averaging using only the relative rotation angle

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science China(Technological sciences) 2023年第10期66卷 2978-2985页

作者： LI Bin SHANG Yang GUAN BangLei LIANG ShunKun SUN XiaoLiang YU QiFeng College of aerospace science and engineering National University of Defense TechnologyChangsha 410073China Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation Changsha 410073China

In this work,we propose multiple rotation averaging using only the relative rotation angle,which is a straightforward camera pose optimization *** use the axis-angle representation to parameterize the rotation and use only relative rotation angles to constrain absolute rotations instead of complete relative *** used with an inertial measurement unit(IMU),our method can obviate the need to estimate and maintain extrinsic parameters between the camera and *** advantage makes our method immune to extrinsic parameters and *** performed extensive evaluations on both synthetic data and publicly available real datasets,which showed that our method was comparable with the state-of-the-art method and achieved a significant gain in accuracy for the visual measurement when applied to the case in which the camera and IMU are tightly fixed.

关键词： multiple rotation averaging pose optimization relative rotation angle IMU

Characteristics of the double layer associated with terrestrial bow shock by THEMIS observation

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science China Earth sciences 2015年第4期58卷 562-572页

作者： LI ShiYou ZHANG ShiFeng CAI Hong BAI XiBin XIE QiuHong College of aerospace science and engineering National University of Defense Technology Unit 75171 the Chinese People's Liberation Army Unit 75707 the Chinese People's Liberation Army

This study presents observation and detailed analysis on the double layers （DLs） in the ramp and the foreshock contacting with the foot of the terrestrial bow shock by THEMIS on September 14, 2008 under enhanced dynamic pressure in the solar wind. The results reveal that：（1） The time duration of the double layers is nus 10-40 mV/m. （2） On assuming a propagation speed at the ion mainly 3-8 ms, and their max parallel electric field is miacoustic speed （vs）, their spatial scale is estimated to be 0.3-1.15 km （about 75-200 2D）. （3） The net potential drop of DLs is estimated to be 5-32 V. （4） The DLs in the ramp and the foreshock contacting to the foot of the bow shock is current-carrying as a result of development and evolution of nonlinear phase of instability in the self-consistent current-carrying plasma. The DLs may play an important role in strong turbulence in the foreshock contacting with the foot of the bow shock.

关键词： bow shock double layer electron hole current-carrying plasma

Transition Metal Carbonitride MXenes Anchored with Pt Sub-Nanometer Clusters to Achieve High-Performance Hydrogen Evolution Reaction at All pH Range

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Nano-Micro Letters 2025年第5期17卷 525-539页

作者： Zhihao Lei Sajjad Ali CI Sathish MuhammadIbrar Ahmed Jiangtao Qu Rongkun Zheng Shibo Xi Xiaojiang Yu MBHBreese Chao Liu Jizhen Zhang Shuai Qi Xinwei Guan Vibin Perumalsamy Mohammed Fawaz Jae-Hun Yang Mohamed Bououdina Kazunari Domen Ajayan Vinu Liang Qiao Jiabao Yi Global Innovative Center of Advanced Nanomaterials College of EngineeringScience and EnvironmentUniversity of NewcastleCallaghanNSW 2308Australia Energy Waterand Environment LabCollege of Humanities and SciencesPrince Sultan University11586 RiyadhSaudi Arabia School of Physics University of SydneySydneyNSW 2000Australia Institute of Chemical and engineering sciences ASTARSingapore 627833Singapore Singapore Synchrotron Light Source National University of SingaporeSingapore 117603Singapore Institute for Frontier Materials Deakin UniversityWaurn PondsVictoria 3216Australia Guangdong Provincial Key Laboratory of Natural Rubber Processing Agricultural Products Processing Research InstituteChinese Academy of Tropical Agricultural SciencesZhanjiang 524001People’s Republic of China College of Chemistry Environmental engineering Shenzhen UniversityShenzhen 518060GuangdongPeople’s Republic of China Research Initiative for Supra-Materials Interdisciplinary Cluster for Cutting Edge Research Shinshu University4-17-1WakasatoNagano-shiNagano 380-8533Japan School of Physics University of Electronic Science and Technology of ChinaChengdu 610054People’s Republic of China department of Chemical engineering and Interdisciplinary Research Center for Hydrogen Technologies and Carbon Management(IRC-HTCM) King Fahd University of Petroleum and Minerals31261 DhahranSaudi Arabia

Transition metal carbides,known as MXenes,particularly Ti_(3)C_(2)T_(x),have been extensively explored as promising materials for electrochemical ***,transition metal carbonitride MXenes with high nitrogen content for electrochemical reactions are rarely *** this work,transition metal carbonitride MXenes incorporated with Pt-based electrocatalysts,ranging from single atoms to sub-nanometer dimensions,are explored for hydrogen evolution reaction(HER).The fabricated Pt clusters/MXene catalyst exhibits superior HER performance compared to the single-atom-incorporated MXene and commercial Pt/C catalyst in both acidic and alkaline *** optimized sample shows low overpotentials of 28,65,and 154 mV at a current densities of 10,100,and 500 m A cm^(-2),a small Tafel slope of 29 m V dec^(-1),a high mass activity of 1203 mA mgPt^(-1)and an excellent turnover frequency of 6.1 s^(-1)in the acidic *** functional theory calculations indicate that this high performance can be attributed to the enhanced active sites,increased surface functional groups,faster charge transfer dynamics,and stronger electronic interaction between Pt and MXene,resulting in optimized hydrogen absorption/desorption toward better *** work demonstrates that MXenes with a high content of nitrogen may be promising candidates for various catalytic reactions by incorporating single atoms or clusters.

关键词： MXene Hydrogen evolution reaction Single atom Two-dimensional nanosheets Density functional theory

Fault detection for networked systems subject to access constraints and packet dropouts

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Journal of Systems engineering and Electronics 2011年第1期22卷 127-134页

作者： Xiongbo Wan Huajing Fang Sheng Fu department of Control science and engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China

This paper addresses the problem of fault detection（FD） for networked systems with access constraints and packet *** independent Markov chains are used to describe the sequences of channels which are available for communication at an instant and the packet dropout process,*** indexes H∞ and H_ are introduced to describe the robustness of residual against external disturbances and sensitivity of residual to faults,*** using a mode-dependent fault detection filter（FDF） as residual generator,the addressed FD problem is converted into an auxiliary filter design problem with the above index constraints.A sufficient condition for the existence of the FDF is derived in terms of certain linear matrix inequalities（LMIs）.When these LMIs are feasible,the explicit expression of the desired FDF can also be characterized.A numerical example is exploited to show the usefulness of the proposed results.

关键词： fault detection(FD) networked control system(NCS) access constraints packet dropouts linear matrix inequality(LMI).

Thrust producing mechanisms in ray-inspired underwater vehicle propulsion

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Theoretical & Applied Mechanics Letters 2015年第1期5卷 54-57页

作者： Geng Liu Yan Ren Jianzhong Zhu Hilary Bart-Smith Haibo Dong department of Mechanical and aerospace engineering University of Virginia

This paper describes a computational study of the hydrodynamics of a ray-inspired underwater vehicle conducted concurrently with experimental measurements. High-resolution stereo-videos of the vehicle＇s fin motions during steady swimming are obtained and used as a foundation for developing a high fidelity geometrical model of the oscillatory fin. A Cartesian grid based immersed boundary solver is used to examine the flow fields produced due to these complex artificial pectoral fin kinematics. Simulations are carried out at a smaller Reynolds number in order to examine the hydrodynamic performance and understand the resultant wake topology. Results show that the vehicle＇s fins experience large spanwise inflexion of the distal part as well as moderate chordwise pitching during the oscillatory motion. Most thrust force is generated by the distal part of the fin, and it is highly correlated with the spanwise inflexion. Two sets of inter-connected vortex rings are observed in the wake right behind each fin. Those vortex rings induce strong backward flow jets which are mainly responsible for the fin thrust generation.

关键词： HydrodynamicsBio-inspired autonomous underwater vehicleComputational fluid dynamicsVortex dynamics

Graphene photonic crystal fiber with large modulation depth

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science China Chemistry 2020年第1期63卷 5-6页

作者： Yang Xu Chao Gao College of Information science and Electronic engineering Zhejiang UniversityHangzhou 310027China department of Polymer science and engineering Zhejiang UniversityHangzhou 310027China

Optical fiber communication has become an important pillar of information technology in the 21 st century due to its advantages of large communication capacity,small signal in terference and good *** the increasing demand for larger capacity,multi-function and security of optical network,the advantages of photonic crystal fiber(PCF)in optical transmission and regulation are gradually emerging[1,2].In particular,the combination of PCF with some functional materials has greatly broadened the application fields of optical ***,as a functional film with high mobility,broadband absorption and adjustable electrical properties,is a promising material for the next generation of photonic and photoelectronic applications[3-5].

关键词： fiber communication network