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Engineering Ru（N^N）3-modified covalent organic framework for photocatalytic olefin epoxidation

Science China Chemistry 2024年第11期67卷 3719-3728页

作者： yan-lin li Sheng-li Huang Guo-Yu yang Key Laboratory of Cluster Science (Ministry of Education) Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion MaterialsSchool of Chemistry and Chemical Engineering Beijing Institute of Technology

Photocatalytic olefin oxidation using air as an oxidant is an environmentally friendly method for producing epoxides. Covalent organic frameworks（COFs） have emerged as promising photocatalysts in various organic synthesis reactions. The combination of tri-（2-pyridinal aldehyde）-containing precursor with 4,4’,4’’-（1,3,5-triazine-2,4,6-triyl）trianiline generated（N^N）-I-COF. Via imine-to-quinoline transformation and coordination anchorage of Ru（N^N）3unit, Ru（N^N）3@Q-COF was obtained with improved chemical stability, skeleton conjugation, and novel photochemical characteristics, and demonstrated excellent photocatalytic activity in olefin epoxidation with a wide range of substrates. The presence of H2O played a crucial role in the formation of reactive oxygen species（ROSs）, which in turn influenced the olefin oxidation process. The hydrophilicity of Ru（N^N）3facilitated the approach of H2O and O2to the photogenerated charges, thereby promoting ROSs generation. The lipophilicity of Q-COF allowed for the absorption of olefin substrates, and its nano-channels increased encountering possibility between olefins and ROSs. Consequently, Ru（N^N）3@Q-COF provided an intriguing platform for olefin photooxidation and could be recycled multiple times without any degradation in performance. This report revealed that the conversion of classical ROSs into less potent oxidants with rapid kinetic rates played a crucial role in achieving highly efficient and selective epoxidation of terminal olefins.

关键词： polypyridyl Ru covalent organic framework olefin epoxidation photocatalysis

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Machine learning model based on non-convex penalized huberized-SVM

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Journal of Electronic Science and Technology 2024年第1期22卷 81-94页

作者： Peng Wang Ji Guo lin-Feng li School of Finance and Economics Xizang Minzu UniversityXianyang712082China Research Center for Quality Development of Xizang Special Industries Xianyang712082China School of Computer Science and Technology Xinjiang UniversityUrumqi830017China

The support vector machine(SVM)is a classical machine learning *** the hinge loss and least absolute shrinkage and selection operator(LASSO)penalty are usually used in traditional ***,the hinge loss is not differentiable,and the LASSO penalty does not have the Oracle *** this paper,the huberized loss is combined with non-convex penalties to obtain a model that has the advantages of both the computational simplicity and the Oracle property,contributing to higher accuracy than traditional *** is experimentally demonstrated that the two non-convex huberized-SVM methods,smoothly clipped absolute deviation huberized-SVM(SCAD-HSVM)and minimax concave penalty huberized-SVM(MCP-HSVM),outperform the traditional SVM method in terms of the prediction accuracy and classifier *** are also superior in terms of variable selection,especially when there is a high linear correlation between the *** they are applied to the prediction of listed companies,the variables that can affect and predict financial distress are accurately filtered *** all the indicators,the indicators per share have the greatest influence while those of solvency have the weakest *** companies can assess the financial situation with the indicators screened by our algorithm and make an early warning of their possible financial distress in advance with higher precision.

关键词： Huberized loss Machine learning Non-convex penalties Support vector machine(SVM)

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Efficient micrometer-scale thick-film perovskite solar cells with superior stability

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Rare Metals 2024年第4期43卷 1647-1657页

作者： Jian-Fei Hu Gang Chen Shun-Zhang Yu Yue-Xin lin Kai-Yu Wang Zong-Wei li Guo-Dong Zhang Teng-Fei Pan ya-Jing li Ming-Jie li Ying-Dong Xia Yi-Fan Lv Yong-Hua Chen Key Laboratory of Flexible Electronics(KLoFE)and Institute of Advanced Materials(IAM) School of Flexible Electronics(Future Technologies)Nanjing Tech University(NanjingTech)Nanjing211816China Department of Applied Physics The Hong Kong Polytechnic UniversityHong Kong999077China Shenzhen Research Institute The Hong Kong Polytechnic UniversityShenzhen518057China Optics Valley Laboratory Hubei430074China

It is essential to enhance the thickness of the absorber layer for perovskite solar cells(PSCs)to improve device performance and reduce industry ***,thick perovskite films(>1μm)are difficult to be fabricated by employing traditional solvents,such as N,N-dimethylformamide(DMF),dimethyl sulfoxide(DMSO).Besides,it is a challenge to fabricate thick-film perovskite owing to the deteriorated surface morphology and serious defect ***,a simple method was reported to deposit uniform pinhole-free perovskite films with a thickness of more than 2μm utilizing the methylamine acetate(MAAc)ionic liquid as the *** with methylammonium chloride(MACl)as an additive,thick-film perovskite with~2μm in grain size and few grain boundaries(GBs)was prepared,which dramatically improved the perovskite crystal quality and enhanced carrier transport *** final PSCs exhibited a power conversion efficiency(PCE)of 20.16%.The device showed improved stability with 95%of its initial efficiency in a nitrogen environment over 5000 *** work provides an alternative strategy to produce extremely efficient and stable thick-film *** can be believed that this device has great potential in the application of large areas and laminated PSCs.

关键词： Perovskite solar cells Thick-film Stability Ionic liquid

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Synergistic Effects of Bay of Bengal Tropical Cyclones and Tibetan Plateau Vortices on Water Vapor Transport over the Tibetan Plateau in Early Summer

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Journal of Meteorological Research 2024年第2期38卷 383-398页

作者： Jialu lin Ying li Beiyao liU Pengchao AN State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 University of Chinese Academy of Sciences Beijing 100049 Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200433

The Bay of Bengal(BoB)tropical cyclones(TCs)and the Tibetan Plateau vortices(TPVs)are two crucial weather systems influencing the Tibetan Plateau(TP).Their synergistic effects can lead to widespread heavy precipitation events on the *** this study,we employ the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPliT)model to track the trajectory of water vapor transport during three large-scale precipitation events on the TP under the combined influence of BoB TCs and *** results indicate that low-level water vapor from the BoB under the influence of BoB TCs was cyclonically entangled into the cyclonic circulation,lifted and transported northward by southwesterly flow to the southeastern part of the TP,which contributes to the moistening of the entire troposphere ***,convergence of the cyclonic circulation of the TPVs on the northern TP further transports water vapor collected in the southeastern TP northward,conducive to the maintenance and development of precipitation systems,thus inducing widespread heavy precipitation events over the TP.

关键词： Bay of Bengal(BoB) tropical cyclones(TCs) Tibetan Plateau vortices(TPVs) trajectory tracing water vapor transport

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Effect of Ellipsoidal Particle Shape on Tribological Properties of Lubricants Containing Nanoparticles

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 231-242页

作者： ling Pan Zhi li Yunhui Chen Guobin lin School of Advanced Manufacturing Fuzhou UniversityQuanzhou 362251FujianChina School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108FujianChina

Adding nanoparticles can significantly improve the tribological properties of ***,there is a lack of understanding regarding the influence of nanoparticle shape on lubrication *** this work,the influence of diamond nanoparticles(DNPs)on the tribological properties of lubricants is investigated through friction ***,the friction characteristics of lubricants regarding ellipsoidal particle shape are investigated using molecular dynamics(MD)*** results show that DNPs can drastically lower the lubricant's friction coefficientμfrom 0.21 to *** shearing process reveals that as the aspect ratio(α)of the nanoparticles approaches 1.0,the friction performance improves,and wear on the wall *** the same time,the shape of the nanoparticles tends to be *** 0.85≤α≤1.0,rolling is ellipsoidal particles'main form of motion,and the friction force changes according to a periodic sinusoidal *** the range of 0.80≤αlipsoidal particles primarily exhibit sliding as the dominant movement ***αdecreases within this range,the friction force progressively *** friction coefficientμcalculated through MD simulation is 0.128,which is consistent with the experimental data.

关键词： Molecular dynamics simulation Nanoparticle additives Ellipsoidal particles Tribological properties

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Multifunctional WSe_(2)/Co_(3)C composite for efficient electromagnetic absorption, EMI shielding, and energy conversion

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Nano Research 2024年第3期17卷 1655-1665页

作者： Yuhang Zhu Tingting liu lin li Maosheng Cao School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics&Electron EngineeringHarbin Normal UniversityHarbin 150025China

Currently,as the electromagnetic(EM)environment becomes increasingly complex,single-function EM materials can hardly resist the increasing electromagnetic interference(EMI),and there is an urgent need to develop multifunctional EM *** this work,multifunctional WSe_(2)/Co_(3)C was prepared by simple hydrothermal *** dielectric performance and EM response were *** absorption,shielding performance,and energy conversion devices were *** tailoring the loading content,WSe_(2)/Co_(3)C can switch between EM absorption and EMI *** maximum shielding effectiveness(SE)of WSe_(2)/Co_(3)C reached 36 dB,and high reflection loss(RL)of-60.28 dB and wide effective absorption bandwidth(EAB)of 6.16 GHz can be obtained at low *** multiple EM attenuation mechanisms brought by the combination of two-dimensional(2D)WSe_(2) and magnetic Co_(3)C are considered to be the main reason for the enhanced EM attenuation *** WSe_(2)/Co_(3)C composite provides a viable candidate for developing multifunctional EM materials in 2–18 GHz.

关键词： WSe_(2) Co_(3)C electromagnetic property microwave absorption electromagnetic interference shielding energy conversion

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Pricing Binary Variables of System-wide Constraints for Power System Optimization

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1131-1144页

作者： Jiaxun li Wei lin Zhifang yang Mikhail Davidson State Key Laboratory of Power Transmission Equipment and System Security and New Technology College of Electrical EngineeringChongqing UniversityChongqing 400030China Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong Kong SAR 999077China Faculty of Computational Mathematics and Cybernetics Moscow State UniversityMoscow 119991Russia IEEE

With the trend of multiple energies or flexible demand in power systems,binary variables appear in systemwide constraints,which are the foundation of marginal pricing currently in *** appropriate pricing method incentivizes compliance of market participants;otherwise,compliance can be incentivized by paying discriminatory uplift payments which jeopardize transparency of *** paper proposes two theorems to examine whether the binary variables brought by multiple energies and flexible demand will impact compliance under marginal *** first theorem shows sufficient conditions with which marginal pricing with fixed binary variables incentivizes compliance,while the second theorem shows sufficient conditions to require uplift *** improve transparency by reducing uplift payments under cases which fall into the second theorem,this paper further proposes a pricing method by combining 1)designed constraints to price binary variables in system-wide constraints,and 2)convex hull pricing to price binary variables in private *** of the proposed theorems and pricing method is verified in an electricity-gas case(consisting of the IEEE 30-bus system and the NGS 10-node system)and the IEEE 118-bus test system.

关键词： Binary variables impact analysis pricing under non-convexities

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A hybrid nickel/iron-pyromellitic acid electrocatalyst for oxygen evolution reaction

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Nano Research 2024年第4期17卷 2481-2491页

作者： Guoqi li lin li Wenlong li Fusheng li Chunze Yuan Nian Zhang Hui Zhang Tsu-Chien Weng School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Center for Transformative Science ShanghaiTech UniversityShanghai 201210China State Key Lab of Fine Chemicals Institute of Artificial PhotosynthesisDUT-KTH Joint Education and Research Center on Molecular DevicesDalian University of Technology(DUT)Dalian 116024China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China

The migration of protons during the oxygen evolution reaction(OER)is a key factor that affects the performance of OER *** enhance proton transportation,we designed a catalyst based on nickel/iron-pyromellitic acid(NiFe-PMA)prepared by the electrochemical deposition *** catalyst exhibited a low overpotential of 188 mV at a current density of 10 mA·cm^(-2),a Tafel slope of 28.2 mV·dec^(-1),and long-term stability for 30 days with a current of 50 mA·cm^(-2).We characterized the NiFe-PMA catalyst using various techniques,including Fourier transform infrared(FTIR)spectroscopy,Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),transmission electron microscopy(TEM),scanning electron microscopy(SEM),and inductively coupled plasma-optical emission spectrometry(ICP-OES).Our results showed that NiFe-PMA contains nickel,iron atoms,and both coordinated and uncoordinated carboxylate ***,XPS data confirmed that carboxylate ligands could adjust the outer electronic structure of metal ions,resulting in the high valence state of Ni in *** result of XAS indicated that the nickel atoms present in the catalyst might be easier to maintain a higher chemical *** investigations using kinetic isotope effects(KIEs)and proton inventory revealed that the uncoordinated carboxylic protons played a crucial role in receiving protons during the OER,which promoted the proton transfer of the rate-determining step of the *** novel electrocatalysts provide a new strategy for designing more active and cost-effective catalysts for the OER.

关键词： nickel/iron-pyromellitic acid oxygen evolution reaction kinetic isotope effects

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Realizing the excellent oxidation resistance of an environmental barrier coating through aluminum surface modification

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Journal of Advanced Ceramics 2024年第7期13卷 976-986页

作者： lin Dong Wen-Qi yang lin Chen Guan-Jun yang Chang-Jiu li State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Xi’an Aerospace Engine Company limited in China Aerospace Science and Technology Corporation Xi’an 710065China

The lifetime of Si-based environmental barrier coatings(EBCs)is constrained by thermally grown SiO_(2)oxidelayer(SiO_(2)-TGO),which can cause premature cracking and *** address this issue,a new approach for surfacemodification using aluminum is *** oxidation performance was examined in a 50 vol%H_(2)O-50 vol%O_(2)environment at 1350℃for up to 300 *** results indicate that a dense ytterbium aluminum garnet(YbAG)layer wasformed after modification,decreasing the porosity by 80%.Due to the elimination of fast diffusion channels and the lowoxygen permeability of YbAG,aluminum modification significantly reduced the growth rate of SiO_(2)-TGO by nearly twoorders of ***,its thickness decreased by more than 70%after 300 h of exposure.A diffusioncontrolled oxidation mechanism indicates that the modified dense surface is equivalent to an initial SiO_(2)layer with a specificthickness,causing a shift in the oxidation time and increasing the oxidation *** research provides valuableinsights for designing Si-based EBC with improved lifetimes.

关键词： environmental barrier coating(EBC) oxidation modification diffusion cracking

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Reactor field reconstruction from sparse and movable sensors using Voronoi tessellation-assisted convolutional neural networks

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Nuclear Science and Techniques 2024年第5期35卷 173-185页

作者： He-lin Gong Han li Dunhui Xiao Sibo Cheng Paris Elite Institute of Technology Shanghai Jiao Tong UniversityShanghai 200240China School of Mathematical Sciences Tongji UniversityShanghai 200092China Department of Computing Data Science InstituteImperial College LondonLondon SW72AZUK

The aging of operational reactors leads to increased mechanical vibrations in the reactor *** vibration of the incore sensors near their nominal locations is a new problem for neutronic field *** field-reconstruction methods fail to handle spatially moving *** this study,we propose a Voronoi tessellation technique in combination with convolutional neural networks to handle this *** from movable in-core sensors were projected onto the same global field structure using Voronoi tessellation,holding the magnitude and location information of the *** convolutional neural networks were used to learn maps from observations to the global *** proposed method reconstructed multi-physics fields(including fast flux,thermal flux,and power rate)using observations from a single field(such as thermal flux).Numerical tests based on the IAEA benchmark demonstrated the potential of the proposed method in practical engineering applications,particularly within an amplitude of 5 cm around the nominal locations,which led to average relative errors below 5% and 10% in the L_(2) and L_(∞)norms,respectively.

关键词： Voronoi tessellation Field reconstruction Nuclear reactors Reactor physics On-line monitoring

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