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Achieving Ultra-Broad Microwave Absorption Bandwidth Around Millimeter-Wave Atmospheric Window Through an Intentional Manipulation on Multi-Magnetic Resonance Behavior

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Nano-Micro Letters 2024年第9期16卷 291-307页

作者： Chuyang Liu Lu Xu Xueyu Xiang Yujing Zhang Li Zhou bo ouyang Fan Wu Dong‑Hyun Kim Guangbin Ji School of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016JiangsuPeople’s Republic of China School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuPeople’s Republic of China School of Physics Nanjing University of Science and TechnologyNanjing 210094JiangsuPeople’s Republic of China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuPeople’s Republic of China School of Physics Chungbuk National UniversityCheongju 28644South Korea Department of Chemistry School of ScienceTianjin UniversityTianjin 300072People’s Republic of China

The utilization of electromagnetic waves is rapidly advancing into the millimeter-wave frequency range,posing increasingly severe challenges in terms of electromagnetic pollution prevention and radar stealth.However,existing millimeter-wave absorbers are still inadequate in addressing these issues due to their monotonous magnetic resonance pattern.In this work,rare-earth La^(3+)and non-magnetic Zr^(4+)ions are simultaneously incorporated into M-type barium ferrite(BaM)to intentionally manipulate the multi-magnetic resonance behavior.By leveraging the contrary impact of La^(3+)and Zr^(4+)ions on magnetocrystalline anisotropy field,the restrictive relationship between intensity and frequency of the multi-magnetic resonance is successfully eliminated.The magnetic resonance peak-differentiating and imitating results confirm that significant multi-magnetic resonance phenomenon emerges around 35 GHz due to the reinforced exchange coupling effect between Fe^(3+)and Fe^(2+)ions.Additionally,Mosbauer spectra analysis,first-principle calculations,and least square fitting collectively identify that additional La^(3+)doping leads to a profound rearrangement of Zr^(4+)occupation and thus makes the portion of polarization/conduction loss increase gradually.As a consequence,the La^(3+)-Zr^(4+)co-doped BaM achieves an ultra-broad bandwidth of 12.5+GHz covering from 27.5 to 40+GHz,which holds remarkable potential for millimeter-wave absorbers around the atmospheric window of 35 GHz.

关键词： Microwave absorption Ultra-broad bandwidth M-type barium ferrite Magnetocrystalline anisotropy field Multimagnetic resonance

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High-density triple-phase contact points for enhanced photocatalytic CO_(2) reduction to methanol

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Chinese Chemical Letters 2024年第2期35卷 252-256页

作者： Hanwen Jian Kaiming Deng Tongyu Wang Chengxi Huang Fang Wu Hailing Huo bo ouyang Xuan Liu Jingjing Ma Erjun Kan Ang Li MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing School of ScienceNanjing University of Science and TechnologyNanjing 210094China College of Information Science and Technology Nanjing Forestry UniversityNanjing 210037China State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering Ningxia UniversityYinchuan 750021China

The efficiency of photocatalytic CO_(2) reduction reaction(PCRR)is restricted by the low solubility and mobility of CO_(2) in water,poor CO_(2) adsorption capacity of catalyst,and competition with hydrogen evolution reaction(HER).Recently,hydrophobic modification of the catalyst surface has been proposed as a potential solution to induce the formation of triple-phase contact points(TPCPs)of CO_(2)(gas phase),H_(2) O(liquid phase),and catalysts(solid phase)near the surface of the catalyst,enabling direct delivery of highly concentrated CO_(2) molecules to the active reaction sites,resulting in higher CO_(2) and lower H+surface concentrations.The TPCPs thus act as the ideal reaction points with enhanced PCRR and suppressed HER.However,the initial synthesis of triple-phase photocatalysts tends to possess a lower bulk density of TPCPs due to the simple structure leading to limited active points and CO_(2) adsorption sites.Here,based on constructing a hydrophobic hierarchical porous TiO_(2)(o-HPT)with interconnected macropores and mesopores structure,we have significantly increased the density of TPCPs in a unit volume of the photocatalyst.Compared with hydrophobic macroporous TiO_(2)(o-MacPT)or mesoporous TiO_(2)(o-MesPT),the o-HPT with increased TPCP density leads to enhanced photoactivity,enabling a high methanol production rate with 1111.5μmol g^(−1) h^(−1) from PCRR.These results emphasize the significance of high-density TPCPs design and propose a potential path for developing efficient PCRR systems.

关键词： Photocatalysis CO_(2)reduction reaction Photocatalyst Triple-phase contact points Methanol

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Interpretable machine learning analysis and automated modeling to simulate fluid-particle flows

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Particuology 2023年第9期80卷 42-52页

作者： bo ouyang Litao Zhu Zhenghong Luo Department of Chemical Engineering School of Chemistry and Chemical EngineeringState Key Laboratory of Metal Matrix CompositesShanghai Jiao TongUniversityShanghai200240China

The present study extracts human-understandable insights from machine learning(ML)-based mesoscale closure in fluid-particle flows via several novel data-driven analysis approaches,i.e.,maximal information coefficient(MIC),interpretable ML,and automated ML.It is previously shown that the solidvolume fraction has the greatest effect on the drag force.The present study aims to quantitativelyinvestigate the influence of flow properties on mesoscale drag correction(H_(d)).The MIC results showstrong correlations between the features(i.e.,slip velocity(u^(*)_(sy))and particle volume fraction(εs))and thelabel H_(d).The interpretable ML analysis confirms this conclusion,and quantifies the contribution of u^(*)_(sy),εs and gas pressure gradient to the model as 71.9%,27.2%and 0.9%,respectively.Automated ML without theneed to select the model structure and hyperparameters is used for modeling,improving the predictionaccuracy over our previous model(Zhu et al.,2020;ouyang,Zhu,Su,&Luo,2021).

关键词： Filtered two-fluid model Fluid-particle flow Mesoscale closure Interpretable machine learning Automated machine learning Maximal information coefficient

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Size-Dependent Oxidation-Induced Phase Engineering for MOFs Derivatives Via Spatial Confinement Strategy Toward Enhanced Microwave Absorption

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Nano-Micro Letters 2022年第6期14卷 294-307页

作者： Hanxiao Xu Guozheng Zhang Yi Wang Mingqiang Ning bo ouyang Yang Zhao Ying Huang Panbo Liu School of Chemistry and Chemical Engineering μNorthwestern Polytechnical UniversityXi’an 710129People’s Republic of China Key Laboratory of Magnetic Materials and Devices Ningbo Institute of Materials Technology&EngineeringChinese Academy of SciencesNingbo 315201People’s Republic of China MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing Nanjing University of Science and TechnologyNanjing 210094People’s Republic of China Department of Mechanical and Materials Engineering University of Western OntarioLondonON N6A 5B9Canada

Precisely reducing the size of metal-organic frameworks(MOFs)derivatives is an effective strategy to manipulate their phase engineering owing to size-dependent oxidation;however,the underlying relationship between the size of derivatives and phase engineering has not been clarified so far.Herein,a spatial confined growth strategy is proposed to encapsulate small-size MOFs derivatives into hollow carbon nanocages.It realizes that the hollow cavity shows a significant spatial confinement effect on the size of confined MOFs crystals and subsequently affects the dielectric polarization due to the phase hybridization with tunable coherent interfaces and heterojunctions owing to size-dependent oxidation motion,yielding to satisfied microwave attenuation with an optimal reflection loss of-50.6 d B and effective bandwidth of 6.6 GHz.Meanwhile,the effect of phase hybridization on dielectric polarization is deeply visualized,and the simulated calculation and electron holograms demonstrate that dielectric polarization is shown to be dominant dissipation mechanism in determining microwave absorption.This spatial confined growth strategy provides a versatile methodology for manipulating the size of MOFs derivatives and the understanding of size-dependent oxidation-induced phase hybridization offers a precise inspiration in optimizing dielectric polarization and microwave attenuation in theory.

关键词： Size-dependent oxidation Phase engineering Coherent interface Dielectric polarization Electron holography

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Particle-scale and sub-grid drag models coupled CFD for simulating the CO methanation in a CFB riser

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Particuology 2023年第12期83卷 178-193页

作者： Jiageng Li Yong Jia bo ouyang bolun Yang Zheng-Hong Luo Zhong-Wen Liu Key Laboratory of Syngas Conversion of Shaanxi Province School of Chemistry&Chemical EngineeringShaanxi Normal UniversityXi'an710119China Department of Chemical Engineering School of Chemistry and Chemical EngineeringState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai200240China School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an710049China

The diffusion and chemical reactions inside the catalyst particles and the heterogeneous flow structure in the computational cells are key factors to affect the accuracy of the coarse-grid simulation in circulating fluidized bed(CFB)methanation reactors.In this work,a particle-scale model is developed to calculate the effective reaction rate considering the transient diffusion and chemical reactions in the particle scale,i.e.,the scale of the single catalyst particle.A modified sub-grid drag model is proposed to consider the effects of the meso-scale and chemical reactions on the heterogeneous gas-solid interaction,where the meso-scale is between the single particle and the whole reactor and featured with the particle cluster.Subsequently,a coupled model is developed by integrating the particle-scale and modified sub-grid drag models into CFD.Moreover,the coupled model is validated to achieve accurate predictions on the CO methanation process in a CFB riser.Notably,the coupled model can be performed with a coarse grid(∼58 times particle diameter)and a large time step(0.005 s)to accelerate the simulation.By simply changing the reaction kinetics,different gas-solid catalytic reaction systems can be simulated by using the coupled model.

关键词： Computational fluid dynamics Circulating fluidized bed co methanation Particle-scale model Drag model

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Enhancing the activity of FeNi bimetallic electrocatalysts on overall water splitting by Nd_(2)O_(3)-induced FeNi lattice contraction

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Journal of Energy Chemistry 2023年第12期87卷 42-50,I0003页

作者： Jiajia Li Yunong Qin Tianyu Tan Qiancheng Zhu bo ouyang Erjun Kan Wenming Zhang Province-Ministry Co-construction Collaborative Innovation Center of Hebei Photovoltaic Technology College of Physics Science and TechnologyHebei UniversityBaoding 071002HebeiChina MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing Nanjing University of Science and TechnologyNanjing 210094JiangsuChina

The development of high-efficiency and cost-effective bifunctional electrocatalysts for overall water splitting remains a formidable challenge.Herein,FeNi-Nd_(2)O_(3) nanoparticles anchored on N-doped carbon nanotubes(FeNi-Nd_(2)O_(3)/NCN) are designed for highly effective overall water splitting via a facile two-step hydrothermal approach.The synthetic FeNi-Nd_(2)O_(3) hetero-trimers(Fe 2p-Ni 2p-Nd 3d orbital coupling)on NCN achieve excellent oxygen evolution reaction(OER) and hydrogen evolution reaction(HER) activities with overpotentials of 270 and 120 mV at 10 mA cm^(-2) in 1 M KOH solution.Moreover,a small voltage of 1.52 V at 10 mA cm^(-2) is achieved when FeNi-Nd_(2)O_(3)/NCN is assessed as bifunctional catalyst for overall water splitting,which is superior to the typically integrated Pt/C and RuO_(2) counterparts(1.54 V at 10 mA cm^(-2)).The related characterizations including X-ray absorption fine structure(XAFS)spectroscopy show that the remarkably improved activity is originated from Nd_(2)O_(3)-induced FeNi bimetallic lattice contraction.Furthermore,density functional theory(DFT) calculations indicate that the lattice contraction reduces binding energies of intermediates by downshifting the position of FeNi bimetallic d-band center relative to the Fermi level to optimize catalytic performance.Therefore,the Nd_(2)O_(3)-induced FeNi bimetallic lattice contraction may provide a new perspective for designing and synthesizing innovative catalytic systems.

关键词： Bifunctional catalyst FeNi-Nd_(2)O_(3)hetero-trimers Lattice contraction Overall water splitting

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Nitrogen doped porous carbon-based bifunctional oxygen electrocatalyst with controllable phosphorus content for zinc-air battery

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Nano Research 2023年第4期16卷 5887-5893页

作者： Shichang Cai Zihan Meng Gaojie Li Yu An Yapeng Cheng Erjun Kan bo ouyang Haining Zhang Haolin Tang School of Material Science and Engineering Henan University of TechnologyZhengzhou 450001China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong LaboratoryXianhu Hydrogen ValleyFoshan 528200China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Department of Applied Physics and Institution of Energy and Microstructure Nanjing University of Science and TechnologyNanjing 210094China

The controllable construction of non-noble metal based bifunctional catalysts with high activities towards oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is of great significance,but remains a challenge.Herein,we reported an effective method to synthesize cobalt-nitrogen doped mesoporous carbon-based bifunctional oxygen electrocatalyst with controllable phosphorus content(Co-N-P_(X)-MC,X=0.5,1.0,1.5,2.0).The mesoporous carbon substrate endowed the asprepared samples with more exposed active surface(236.50 m^(2)·g^(−1))and the most appropriate doping ratio of phosphorus had been investigated to be 1.5(Co-N-P1.5-MC).For ORR,Co-N-P1.5-MC exhibited excellent catalytic activity with more positive onset potential(1.01 V)and half-wave potential(0.84 V)than the other samples.For OER,Co-N-P1.5-MC also showed a low overpotential of 415 mV.Combining experimental results and density-functional theory(DFT)calculations,the outstanding bifunctional catalytic performance of Co-N-P1.5-MC was due to the synergistic cooperation between the P and N dopants,which could reduce the reaction barriers and was favorable for ORR and OER.Moreover,the Zn-air battery using Co-N-P1.5-MC as the cathode showed remarkable battery performance with high stability(could operate stably for over 160 h at 10 mA·cm^(−2))and maximum power density(119 mW·cm^(−2)),demonstrating its potential for practical applications.This work could provide significant enlightenment towards the design and construction of bifunctional oxygen electrocatalyst for next-generation electrochemical devices.

关键词： cobalt-nitrogen doped porous carbon phosphorus doping bifunctional electrocatalyst oxygen reduction reaction(ORR)and oxygen evolution reaction(OER) Zn-air battery

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Task Autonomy of a Flexible Endoscopic System for Laser-Assisted Surgery

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Cyborg and Bionic Systems 2022年第1期2022卷 64-74页

作者： Hangjie Mo Xiaojian Li bo ouyang Ge Fang Yuanjun Jia Hong Kong Centre for Cerebro-Cardiovascular Healh Engineering Hong Kong China School of Management Hefei University of TechnologyHefei China Department of Mechanicai Enginering The University of Hong Kong Hong Kong China Department of Automation University of Science and Technology of ChinaHefeiChina

Laser beam string has ben widely studied forthe automation ofsurgery.Currently fexible instruments for laser surgery areoperated entirely by surgeons,which keeps the automation of endoluminal surgery at the initial level.This paper introducesthe design of a new workflow that enables the task autonomy of laser-assisted surgery in constrained environments such as thegastrointestinal(GI)tract with a flexible continuum robotic system.Unlike current,laser steering systems driven bypiezoelectric require the use of high voltage and are risky.This paper describes a tendon-driven 2mm diameter flexiblemanipulator integrated with an endoscope toster thelaser beamBy separating its motionfrom the total endoscopic systemthe designed flexible manipulator can automatically manipulate the laser beam.After the surgical site is searched by thesurgeon with a master/slave control,a population-based model-free control method is applied for the fexible manipulatortoachieve accurate laser beam steering while overcoming the noise from the visual feedback and disturbances from environmentduring operation.Simulations and experiments are performed with the system and control methods to demonstrate theproposed framework in a simulated constrained environment.

关键词： Surgery entirely string

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Aminolysis of ethyl acetate in continuous flow and its reaction kinetics

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Chinese Journal of Chemical Engineering 2019年第12期27卷 2948-2952页

作者： Tao Shen bo ouyang Chao Qian Xinzhi Chen Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China Zhejiang Garden Biochemical High-Tech Co. LTDDongyan 322121China Research Institute of Zhejiang University-Quzhou Quzhou 324000China

The aminolysis of ethyl acetate was promoted significantly via continuous reaction in a tubular reactor.Npropylacetamide was thus synthesized without presence of solvent and catalyst.The optimum conditions were obtained as follows:the reaction temperature is 218℃,the reaction pressure is 3.5 MPa,the molar ratio(ethyl acetate:N-propylamine)is 1:1,and the residence time is 350 min.Accordingly,the conversion of ethyl acetate is up to94.8%.Furthermore,the kinetics of the rapid reaction stage(when the conversion of ethyl acetate is 20%-80%)can be expressed as Ink=-4629.441/T+2.1366,and the apparent activation energy is Ea=38489 J·mol-1.

关键词： Tubular reactor Reaction kinetics Ethyl acetate Aminolysis

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无人机集群联合拓扑控制的智能路由规划方法

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通信学报 2024年第2期45卷 137-149页

作者：颜志易正伦欧阳博王耀南湖南大学电气与信息工程学院湖南长沙410082

针对现有无人机集群路由协议拓扑适变能力弱,易产生包重传、能量空洞和高时延,严重恶化了数据路由性能的问题,针对无人机集群中集群拓扑与路由的耦合特性,提出了一种联合拓扑控制的智能路由规划(IRPJTC)方法。该方法由基于虚拟力的自适... 详细信息

针对现有无人机集群路由协议拓扑适变能力弱,易产生包重传、能量空洞和高时延,严重恶化了数据路由性能的问题,针对无人机集群中集群拓扑与路由的耦合特性,提出了一种联合拓扑控制的智能路由规划(IRPJTC)方法。该方法由基于虚拟力的自适应拓扑控制(VFATC)和基于近端策略优化的地理路由规划(PPO-GRP)组成。其中,VFATC使各无人机根据邻居运动状态信息自适应调整与邻居的距离,保证集群中链路的稳定连接;进一步,PPO-GRP引入VFATC中的链路稳定性指标,并结合端到端时延与能耗指标,设计多目标奖励函数,采用深度强化学习中的近端策略优化算法训练路由策略。仿真实验结果表明,IRPJTC相比于现有路由方法,能在保证分组传输成功率的同时,使端到端时延降低12.11%,无人机集群能耗降低4.56%,且具备更强的能耗均衡能力。

关键词：无人机集群路由协议拓扑控制近端策略优化深度强化学习

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