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Spatial-five coordination promotes the high efficiency of CoN_(4) moiety in graphene-based bilayer for oxygen reduction electrocatalysis: A density functional theory study

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Chinese Journal of Chemical Engineering 2023年第2期54卷 106-113页

作者： Libing yu Qiuyan huang Jing Wu Erhong Song Beibei xiao School of Energy and Power Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China The State Key Laboratory of High Performance Ceramics and Superfine MicrostructureShanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China

The searching of highly efficient catalysts for oxygen reduction reaction(ORR) has attracted particular attention. In this work, we construct the graphene-based bilayers BG/X that consists by the CoN_(4) embedded graphene as the upper layer and the X modified graphene as the bottom layer(X = Si, P, S). The interfacial bonding between CoN_(4) site and the X dopant is spontaneously formed due to the strong pd hybridization, which changes the Co ligand from the planar-four N_(4) coordination into spatial-five N_(4)+X one. The additive glue atom weakens too strong adsorptions of the ORR intermediates on CoN_(4) site and thereby improves the ORR activities in comparison with the monolayer counterpart. From the free energy profiles, the overpotentials η are 0.47, 0.49 and 0.45 V for BG/Si_(a), BG/P_(a) and BG/S_(a), respectively,being comparable to that of state-of-the-art Pt material. Besides, the kinetic barriers for the bilayers are less than 0.75 eV, an indicative of the room temperature activity. Furthermore, the combination of thermodynamic and kinetic analysis ensures the preference of 4e^(-)-OOH associative mechanism over 2e^(-)-H_(2)O_(2) mechanism, being beneficial for membrane stability against the H_(2)O_(2) corrosion. Therefore,the graphene-based bilayers deliver the high efficiencies for oxygen reduction electrocatalysis.Therefore, the interfacial bonding in the graphene-based bilayers provides an interesting strategy to suppress the poisoning phenomenon for the material design from atom scale.

关键词： Catalysts Oxygen reduction reaction(ORR) Graphene Thermodynamic Kinetic

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Design of multilayer cellular neural network based on memristor crossbar and its application to edge detection

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Journal of Systems Engineering and Electronics 2023年第3期34卷 641-649页

作者： yu Yongbin TANG Haowen FENG xiao WANG Xiangxiang huang Hang School of Information and software Engineering University of Electronic Science and Technology of ChinaChengdu 610054China

Memristor with memory properties can be applied to connection points(synapses)between cells in a cellular neural network(CNN).This paper highlights memristor crossbar-based multilayer CNN(MCM-CNN)and its application to edge detection.An MCM-CNN is designed by adopting a memristor crossbar composed of a pair of memristors.MCM-CNN based on the memristor crossbar with changeable weight is suitable for edge detection of a binary image and a color image considering its characteristics of programmablization and compactation.Figure of merit(FOM)is introduced to evaluate the proposed structure and several traditional edge detection operators for edge detection results.Experiment results show that the FOM of MCM-CNN is three times more than that of the traditional edge detection operators.

关键词： edge detection figure of merit(FOM) memristor crossbar synaptic circuit memristor crossbar-based cellular neural network(MCM-CNN)

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Multiscale spatiotemporal meteorological drought prediction:A deep learning approach

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Advances in Climate Change Research 2024年第2期15卷 211-221页

作者： Jia-Li ZHANG xiao-Meng huang yu-Ze SUN Department of Earth System Science Ministry of Education Key Laboratory for Earth System ModellingInstitute for Global Change StudiesTsinghua UniversityBeijing 100084China

Reliable monitoring and thorough spatiotemporal prediction of meteorological drought are crucial for early warning and decision-making regarding drought-related disasters.The utilisation of multiscale methods is effective for a comprehensive evaluation of drought occurrence and progression,given the complex nature of meteorological drought.Nevertheless,the nonlinear spatiotemporal features of meteorological droughts,influenced by various climatological,physical and environmental factors,pose significant challenges to integrated prediction that considers multiple indicators and time scales.To address these constraints,we introduce an innovative deep learning framework based on the shifted window transformer,designed for executing spatiotemporal prediction of meteorological drought across multiple scales.We formulate four prediction indicators using the standardized precipitation index and the standard precipitation evaporation index as core methods for drought definition using the ERA5 reanalysis dataset.These indicators span time scales of approximately 30 d and one season.Short-term indicators capture more anomalous variations,whereas long-term indicators attain comparatively higher accuracy in predicting future trends.We focus on the East Asian region,notable for its diverse climate conditions and intricate terrains,to validate the model's efficacy in addressing the complexities of nonlinear spatiotemporal prediction.The model's performance is evaluated from diverse spatiotemporal viewpoints,and practical application values are analysed by representative drought events.Experimental results substantiate the effectiveness of our proposed model in providing accurate multiscale predictions and capturing the spatiotemporal evolution characteristics of drought.Each of the four drought indicators accurately delineates specific facets of the meteorological drought trend.Moreover,three representative drought events,namely flash drought,sustained drought and severe drought,underscore the significance of selecting appropr

关键词： Meteorological drought Spatiotemporal prediction Multiscale Swim transformer Deep learning

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Growth of Ag/g-C_(3)N_(4) nanocomposites on nickel foam to enhance photocatalytic degradation of formaldehyde under visible light

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Journal of Environmental Sciences 2024年第3期137卷 432-442页

作者： Ze Wang Zhi huang Jiang yu xiao Shao Weidong Peng Jie yu Yinying Jiang Department of Environmental Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Institute of New Energy and Low Carbon Technology Sichuan UniversityChengdu 610065China School of Agriculture and Environment University of Western AustraliaPerth 6907Western AustraliaAustralia Yibin Institute of Industrial Technology Sichuan UniversityYibin 644000China

Formaldehyde is a pollutant that significantly affects the indoor air quality.However,conventional remediation approaches can be challenging to deal with low-concentration formaldehyde in an indoor environment.In this study,Photocatalysts of Ag/graphitic carbon nitride(g-C_(3)N_(4))/Ni with 3D reticulated coral structure were prepared by thermal polymerization and liquid phase photo-deposition,using nickel foam(NF)as the carrier.Experiments demonstrated that when the Ag concentration was 3%,and the relative humidity was 60%,the Ni/Ag/g-C_(3)N_(4)showed the maximum degradation rate of formaldehyde at 90.19%under visible light irradiation,and the formaldehyde concentration after degradation was lower than the Hygienic standard stated by the Chinese Government.The porous structure of Ni/Ag/g-C_(3)N_(4)and the formation of Schottky junctions promoted the Adsorption efficiency and degradation of formaldehyde,while the nickel foam carrier effectively promoted the desorption of degradation products.Meanwhile,the degradation rate was only reduced by3.4%after 16 recycles,the three-dimensional porous structure extended the lifetime of the photocatalyst.This study provides a new strategy for the degradation of indoor formaldehyde at low concentrations.

关键词： Graphitic carbon nitride(g-C_(3)N_(4)) Nickel foam(NF) Ag Formaldehyde Photocatalysis

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Measure Complexity and Rigid Systems

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Acta Mathematica Sinica,English Series 2022年第1期38卷 68-84页

作者： Wen huang Run Ju WEI Tao yu xiao Min ZHOU CAS Wu Wen-Tsun Key Laboratory of Mathematics School of Mathematical SciencesUniversity of Science and Technology of ChinaHefei 230026P.R.China Department of Mathematics Shantou UniversityShantou 515063P.R.China Department of Mathematics Huazhong University of Science and TechnologyWuhan 430074P.R.China

In this paper we introduce two metrics:the max metric d_(n,q)and the mean metric d_(n,q).We give an equivalent characterization of rigid measure preserving systems by the two metrics.It turns out that an invariant measureμon a topological dynamical system(X,T)has bounded complexity with respect to d_(n,q)if and only ifμhas bounded complexity with respect to d_(n,q)if and only if(X,B_X,μ,T)is rigid.We also obtain computation formulas of the measure-theoretic entropy of an ergodic measure preserving system(resp.the topological entropy of a topological dynamical system)by the two metrics dn,q and dn,q.

关键词： Rigid system entropy bounded complexity

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Recurrence of Transitive Points in Dynamical Systems with the Specification Property

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Acta Mathematica Sinica,English Series 2018年第12期34卷 1879-1891页

作者： xiao Yi WANG yu huang School of Mathematics and Statistics Zhaoqing University Zhaoqing 526061 P. R. China Department of Mathematics Sun Yat-sen University Guangzhou 510275 P. R. China

Let T ： X →X be a continuous map of a compact metric space X. A point x E X is called Banach recurrent point if for all neighborhood V of x, （n ∈ N ： T^n（x） ∈ V} has positive upper Banach density. Denote by Tr（T）, W（T）, QW（T） and BR（T） the sets of transitive points, weakly almost periodic points, quasi-weakly almost periodic points and Banach recurrent points of （X, T）. If （X, T） has the specification property, then we show that every transitive point is Banach recurrent and O≠ W（T） n Tr（T） ≠ W＊（T） ∩ Tr（T） ≠ QW（T） ∩ Tr（T） ≠ BR（T） ∩ Tr（T）, in which W＊（T） is a recurrent points set related to an open question posed by Zhou and Feng. Specifically the set Tr（T） M W＊（T）／ W（T） is residual in X. Moreover, we construct a point x E BR ／ QW in symbol dynamical system, and demonstrate that the sets W（T）, QW（T） and BR（T） of a dynamical system are all Borel sets.

关键词： Specification property invariant measures recurrent points measure center

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A simple and efficient carbon nanotube-based nanocarriers simultaneously delivers multiple plasmids into diverse mature tissues of monocotyledonous crops

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Science China(Life Sciences) 2023年第7期66卷 1701-1704页

作者： Xuedong Liu Wenwen Kong Nian xiao Lijuan huang yu Zhang Weizhao Chen Beixin Mo yu yu Guangdong Provincial Key Laboratory for Plant Epigenetics Longhua Bioindustry and Innovation Research InstituteCollege of Life Sciences and OceanographyShenzhen UniversityShenzhen518060China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic EngineeringShenzhen UniversityShenzhen518060China Instrumental Analysis Center of Shenzhen University(Lihu Campus) Shenzhen UniversityShenzhen518060China

Dear Editor,With the development of high-throughput sequencing technology,a large number of functional genes have been identified.However,the illustration of these gene functions is limited,especially in monocot plants(Chen et al.,2022).One of the main reasons is that genetic transformation is still a major bottleneck for these plants.Recently,nanoparticles(NPs)-mediated biomolecular delivery methods.

关键词： mono illustration crops

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Living Crystallization-Driven Self-Assembly of Oligo(p-phenylene vinylene)-Containing Block Copolymers:Impact of Branched Structure of Alkyl Side Chain ofπ-Conjugated Segment

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Chinese Journal of Polymer Science 2023年第4期41卷 574-584,I0008页

作者： Yang Song Bo Xiang xiao-yu huang Guo-Lin Lu Chun Feng School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai200093China Shanghai Key Laboratory of Advanced Polymeric Materials School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai200237China Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200032China

The structure of side chains ofπ-conjugated segments is a critical factor determining living crystallization-driven self-assembly(CDSA),a versatile platform to generate fiber-like nanostructures with precise length and composition.Herein,we design and synthesize three block copolymers(BCPs)containing same corona-forming poly(N-isopropyl acrylamide)(PNIPAM)segment,but different core-formingπ-conjugated oligo(p-phenylene vinylene)(OPV)with linear pentyl(l-OPV),racemic 2-methyl butyl(r-OPV)and stereo-regular chiral(S)-2-methyl butyl(c-OPV)side chains,respectively.By using these BCPs of l-OPV-b-PNIPAM_(47),r-OPV-b-PNIPAM_(47)and c-OPV-b-PNIPAM_(47)as model,we aim to get a deep insight into how steric and stereo-regular effect induced by branched alkyl side chains of OPV segment affects the living CDSA.The results showed that l-OPV-b-PNIPAM_(47)exhibits typical characteristics of self-seeding and seeded growth of living CDSA to give uniform fiber-like micelles of controlled length.On the contrary,r-OPV-b-PNIPAM_(47)and c-OPV-b-PNIPAM_(47)with branched racemic and stereo-regular chiral alkyl side chains are more prone to self-nucleation during the micellar elongation to give short and polydisperse fiber-like micelles.The obvious selfnucleation during the micellar elongation of r-OPV-b-PNIPAM_(47)and c-OPV-b-PNIPAM_(47)is due to the increase of steric repulsion with OPV units induced by branched alkyl side chains,not the stereo-irregular effect of racemic alkyl side chains.

关键词： π-Conjugated polymer Nanofiber Living crystallization-driven self-assembly Structure effect

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Toward high-sulfur-content,high-performance lithium-sulfur batteries:Review of materials and technologies

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Journal of Energy Chemistry 2023年第5期80卷 625-657,I0014页

作者： Fulai Zhao Jinhong Xue Wei Shao Hui yu Wei huang Jian xiao School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Basic Department Jinci College of Shanxi Medical UniversityTaiyuan 030025ShanxiChina School of Engineering Westlake UniversityHangzhou 310024ZhejiangChina School of Physics and Electronic Information Shangrao Normal UniversityShangrao 334001JiangxiChina

Lithium sulfur batteries(LSBs)are recognized as promising devices for developing next-generation energy storage systems.In addition,they are attractive rechargeable battery systems for replacing lithium-ion batteries(LIBs)for commercial use owing to their higher theoretical energy density and lower cost compared to those of LIBs.However,LSBs are still beset with some persistent issues that prevent them from being used industrially,such as the unavoidable dissolution of lithium polysulfide intermediates during electrochemical reactions and large volume expansion(up to 80%)upon the formation of Li_(2)S,resulting in serious battery life and safety limitations.In the process of solving these problems,it is necessary to maintain a high sulfur content in the cathode materials to ensure that the LSBs have high energy densities and excellent cycle performance.In this review,the novel preparation methods and cathode materials used for preparing LSBs in recent years are reviewed considering the sulfur content and cycle performance.In addition,the problems and difficulties in practically applying cathode materials are described,and the development trend is discussed.

关键词： Lithium sulfur batteries Cathode material High sulfur content Cycle performance

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Enhanced electromagnetic wave absorption properties of ZIF-67 modified polymer-derived SiCN ceramics by in situ construction of multiple heterointerfaces

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Rare Metals 2023年第5期42卷 1635-1644页

作者： Tao-Bo Geng Gao-yuan yu Gao-Feng Shao xiao-Gu huang School of Chemistry and Materials Science Nanjing University of Information Science&TechnologyNanjing210044China

Multiphase polymer-derived ceramics have the advantages of thermal stability and adjustable dielectric properties,which exhibit significant potential for use in high-temperature microwave absorbing materials.Herein,Co-containing polymer-derived SiCN(Co-SiCN)ceramics were successfully synthesized by the physical mixing of zeolitic imidazolate framework(ZIF)-67 and polysilazane precursors and subsequent pyrolysis.The phase and chemical compositions,microstructures,dielectric properties,electromagnetic wave absorption(EWA)performance,and mechanism of the ceramics were investigated.The results showed that the introduction of ZIF-67 promoted the in situ formation of dielectric loss phases,including SiC nanocrystals,CoSi nanocrystals,and free carbon.The phase composition can be regulated by controlling the pyrolysis temperature to achieve ideal EWA properties.The Co-SiCN ceramic pyrolyzed at 1500℃demonstrated excellent EWA performance,with a maximum effective absorption band(EAB_(max))of 3.0 GHz at an ultralow thickness of 1.05 mm and minimum reflection loss(RL_(min))of-46.4 dB at a low frequency of 6 GHz.Compared with other reported SiCN-based ceramics containing magnetic metals,the ceramics prepared in this study stand out because of their low RL and high EAB at low thicknesses.The superior microwave absorption performance of the Co-SiCN ceramics is attributed to the heterointerface polarization,and impedance matching induced by the synergistic effects of their co-existing electromagnetic transparent/absorption phases.This study provides new insights into the development of high-performance SiCNbased microwave absorbers.

关键词： Polymer-derived SiCN ceramic Multiple heterointerfaces Zeolitic imidazolate framework(ZIF-67) Electromagnetic wave absorption(EWA)

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