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Stable hydrogen-bonded organic frameworks and their photo-and electro-responses

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Nano Research 2024年第8期17卷 7675-7699页

作者： Ying Hou Xin-Song Huang Sheng-Hao Gong Chen liu Yangyang liu tian-Fu liu State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China Department of Chemistry and Biochemistry California State UniversityLos AngelesCalifornia 90032USA College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350007China

Hydrogen-bonded organic frameworks(HOFs)are a recent class of porous materials that have garnered considerable research interest owing to their distinctive *** can be constructed through judicious selection of H-bonding motifs,which are further enforced by other weak intermolecular interactions such asπ–πstacking,van der Waals forces,and framework *** advantage of these interactions,we can expand the functional field of HOFs by introducing active ***,researchers have made substantial advancements in using HOFs for chemical sensing,catalysis,proton conduction,biological applications,and *** low bonding energy of H-bonds allows for precise control over the concentration of ligands in solvents,forming diverse HOF *** varied structures offer significant advantages for producing HOFs with photo-responsive and electro-responsive ***,the presence of H-bonds in HOFs results in their inherent lower stability compared to metal-organic frameworks(MOFs)and covalent-organic frameworks(COFs)formed via coordination and covalent bonds,*** a result,the pursuit of stable and innovative HOF materials with novel functional sites remains an ongoing *** review provides an overview of recent research progress in the development of new strategies for stable HOF synthesis and applications of HOFs with stimuli-responsive *** first classified all synthetic methods reported to date and discussed the stable HOFs synthesized,as well as their unique properties and *** addition,we summarized the applications of HOFs utilizing their synergistic responses to external stimuli,including photo,electrical,pressure,and chemical *** systematically reviewed stable HOF synthesis and applications,which may lead to a deeper understanding of the structure–activity relationship for these materials and guide future HOF design.

关键词： stable hydrogen-bonded organic frameworks(HOFs) photo-response electro-response photoelectric synergistic response

CFD-DEM simulation of fluorination reaction in fluidized beds with local grid and time refinement method

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Particuology 2024年第1期84卷 145-157页

作者： Mofan qiu Lin Jiang Rongzhen liu Yaping Tang Malin liu Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyTsinghua UniversityBeijing100084China

The gas-solid reaction process with wide particle size distribution is extensively used in the chemical engineering field,especially the particle reacts with the gas gradually,such as fluorination reactions in fluidized *** the computational fluid dynamics-discrete element method(CFD-DEM)is used for the coupling simulation of multiphase and polydisperse particle reaction system,the grid size directly affects the accuracy of flow field information and simulation of chemical ***,particle calculation time step will directly affect the efficiency of coupling *** this work,a local grid and time step refinement method is proposed to simulate multiphase and polydisperse particle fluid-ization reaction *** this method,the refined DEM grids are automatically generated in the computational domain around the fine particles,and the detailed fluid phase information is obtained with the interpolation *** the two-phase coupling process,particles are divided into different groups based on physical properties,each group has its own independent time *** multistage conical-cylindrical spouted bed is proposed for the fluorination reaction process;the operating gas ve-locity range of the polydisperse particle system is extended by the new design while the particle size distribution changes with the gas-solid reaction *** is demonstrated that the local grid and time step refinement method can improve the accuracy and efficiency of the traditional CFD-DEM method in the reaction process simulation,which describes a polydisperse particle system with wide particle size *** at improving the simulation accuracy and efficiency,this paper will be helpful for simulating the particle reaction process in the gas-solid fluidized bed and beneficial for the development of the CFD-DEM method.

关键词： CFD-DEM Polydisperse particle Two-phase flow Fluidized bed

Off-Grid Compressed Channel Estimation with Parallel Interference Cancellation for Millimeter Wave Massive MIMO

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China Communications 2024年第3期21卷 51-65页

作者： liu Jinru tian Yongqing liu Danpu Zhang Zhilong Beijing Laboratory of Advanced Information Network Beijing Key Laboratory of Network System Architecture and ConvergenceBeijing University of Posts and TelecommunicationsBeijing100876China

Millimeter wave(mmWave)massive multiple-input multiple-output(MIMO)plays an important role in the fifth-generation(5G)mobile communications and beyond wireless communication systems owing to its potential of high ***,channel estimation has become very challenging due to the use of massive MIMO antenna ***,the mmWave channel has strong sparsity in the spatial angle domain,and the compressed sensing technology can be used to convert the original channel matrix into the sparse matrix of discrete angle *** the high-dimensional channel matrix estimation is transformed into a sparse recovery problem with greatly reduced computational ***,the path angle in the actual scene appears randomly and is unlikely to be completely located on the quantization angle grid,thus leading to the problem of power ***,multiple paths with the random distribution of angles will bring about serious interpath interference and further deteriorate the performance of channel *** address these off-grid issues,we propose a parallel interference cancellation assisted multi-grid matching pursuit(PIC-MGMP)algorithm in this *** proposed algorithm consists of three stages,including coarse estimation,refined estimation,and inter-path cyclic iterative inter-ference *** specifically,the angular resolution can be improved by locally refining the grid to reduce power leakage,while the inter-path interference is eliminated by parallel interference cancellation(PIC),and the two together improve the estimation *** results show that compared with the traditional orthogonal matching pursuit(OMP)algorithm,the normalized mean square error(NMSE)of the proposed algorithm decreases by over 14dB in the case of 2 paths.

关键词： channel estimation compressed sensing inter-path interference millimeter wave massive MIMO off-grid parallel interference cancellation

Optimizing electronic structure of Mo_(2)TiC_(2)T_(x) MXene through Nb doping for enhanced electrochemical performance

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Nano Research 2024年第8期17卷 7174-7181页

作者： Jingyuan Zhao Wenzheng Yan Zhaoxi liu Xiaobin liu Yapeng tian Xinwei Cui Henan Institute of Advanced Technology College of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450003China College of Physics and Electronic Information Engineering Guilin University of TechnologyGuilin 514004China

MXene is a promising electrode material for both high volumetric capacitance and high-rate performance in ***,the current study has mainly focused on the monometallic element Ti_(3)C_(2)T_(x) MXene until now,while the bimetallic and multimetallic MXene have received comparatively less *** this work,we demonstrate that the electronic structure of the Mo_(2)TiC_(2)T_(x) MXene could be regulated by fine-tuning the content of doped Nb *** enhanced electron cloud density of surface–O termination and the electron spin of the Mo atoms in the Mo_(2)TiC_(2)T_(x) MXene,leads to the boost of electric double-layer capacitor(EDLC)and improvement of *** a consequence,the electrochemical performance of Nb-doped Mo_(2)TiC_(2)T_(x) MXene(Nb-0.3-MXene)demonstrates a capacitance of 398 F·cm^(−3),roughly doubling that of the pristine Mo_(2)TiC_(2)T_(x) MXene electrode at 197 F·cm^(−3) in the 3 M H_(2)SO_(4) *** the same time,the Nb-0.3-MXene could even maintain a capacitance of 82.75% at 200 mV·s−1,with high cyclic stability for 19,000 cycles at 10 A·g−***,Nb-0.3-MXene-based hybrid supercapacitors deliver a remarkable volumetric energy density of 48.1 W·h·L^(−1)at 230.7 W·L^(−1),and 34.4 W·h·L^(−1)at a high power density of 82.6 kW·L^(−1).There exists a balance between the volumetric capacitance and rate performance with different ratios of Nb atoms in the Nb-doped MXene due to the strong interaction between the Nb-doped MXene and the intercalated ***,optimizing the electronic structure of MXene through heteroatom doping is of great potential for enhanced supercapacitor performance.

关键词： niobium doping electronic structure Mo_(2)TiC_(2)T_(x)MXene electron spin rate performance volumetric capacitance

y-Tuning: an efficient tuning paradigm for large-scale pre-trained models via label representation learning

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Frontiers of Computer Science 2024年第4期18卷 107-116页

作者： Yitao liu Chenxin AN Xipeng qiu School of Computer Science Fudan UniversityShanghai 200433China

With current success of large-scale pre-trained models(PTMs),how efficiently adapting PTMs to downstream tasks has attracted tremendous attention,especially for PTMs with billions of *** work focuses on designing parameter-efficient tuning paradigms but needs to save and compute the gradient of the whole computational *** this paper,we propose y-Tuning,an efficient yet effective paradigm to adapt frozen large-scale PTMs to specific downstream tasks.y-Tuning learns dense representations for labels y defined in a given task and aligns them to fixed feature *** computing the gradients of text encoder at training phrase,y-Tuning is not only parameterefficient but also *** results show that for DeBERTaxxL with 1.6 billion parameters,y-Tuning achieves performance more than 96%of full fine-tuning on GLUE Benchmark with only 2%tunable parameters and much fewer training costs.

关键词： pre-trained model lightweight fine-tuning paradigms label representation

Models to Simulate Effective Coverage of Fire Station Based on Real-Time Travel Times

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 483-513页

作者： Sicheng Zhu Dingli liu Weijun liu Ying Li tian Zhou Department of Engineering Management Changsha University of Science and TechnologyChangsha410114China

In recent years,frequent fire disasters have led to enormous damage in *** firefighting rescues can minimize the losses caused by *** the rescue processes,the travel time of fire trucks can be severely affected by traffic conditions,changing the effective coverage of fire ***,it is still challenging to determine the effective coverage of fire stations considering dynamic traffic *** paper addresses this issue by combining the traveling time calculationmodelwith the effective coverage *** addition,it proposes a new index of total effective coverage area(TECA)based on the time-weighted average of the effective coverage area(ECA)to evaluate the urban fire *** also selects China as the case study to validate the feasibility of the models,a fire station(FS-JX)in ***-JX station and its surrounding 9,117 fire risk points are selected as the fire service supply and demand points,respectively.A total of 196 simulation scenarios throughout a consecutiveweek are ***,1,933,815 sets of valid sample data are *** results showed that the TECA of FS-JX is 3.27 km^(2),which is far below the standard requirement of 7.00 km^(2) due to the traffic *** visualization results showed that three rivers around FS-JX interrupt the continuity of its effective *** proposed method can provide data support to optimize the locations of fire stations by accurately and dynamically determining the effective coverage of fire stations.

关键词： Fire services fire station effective coverage real-time traffic simulation

Modeling Method of Multi-Energy Systems Based on LSTM Algorithm

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1701-1709页

作者： Di qiu Fei Chen Dong liu Min Cao Siyang liu Shanghai Jiao Tong University Shanghai 200240China Yunnan Power Grid Co. Ltd

The development of the Energy Internet has improved the efficiency of energy utilization and promoted sustainable development of power and energy *** multi-energy system modeling considering the dynamic process of transmission line is one of the key research points of Energy Internet operation *** the energy circuit theory,the lumped parameter model of natural gas pipelines is built and the dynamic characteristic parameters under the control instruction are *** with dynamic characteristic parameters,the long short-term memory(LSTM)neural network is designed to fit the natural gas pipeline dynamic process into discrete linear time-varying(LTV)*** with the equations,an energy hub method is used to build a control model of industrial parks with multi-energy distribution *** the rolling optimal control strategy given in this paper,the model is solved by the Matlab-Yalmip solver and rolling control instructions of each energy conversion unit are ***,the case study demonstrates that the LSTM neural network-based modeling method presented in this paper can accurately fit the dynamic process of a natural gas pipeline *** rolling control model of the multi-energy system can improve the efficiency of energy utilization,exhibit the transmission line status constraints during the optimization control process and improve reliability of the multi-energy system operation.

关键词： Energy hub LSTM multi-energy supply system pipeline system modeling

Green synthesis of luminescent La-MOF nanoparticle from waste poly(ethylene terephthalate) for high-performance in Fe(Ⅲ) detection

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Rare Metals 2024年第8期43卷 3833-3843页

作者： Zhi Gong Zhi-Kui Dai Zhi-Yue Dong qiu-Xuan liu Valentin A.Milichko Hua-Jian liu Jie liu Ran Niu Jiang Gong Key Laboratory of Material Chemistry for Energy Conversion and Storage Hubei Key Laboratory of Material Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective MaterialsSemiconductor Chemistry CenterSchool of Chemistry and Chemical EngineeringMinistry of EducationHuazhong University of Science and TechnologyWuhan 430074China School of Chemical Engineering and Pharmacy Wuhan Institute of TechnologyWuhan 430073China Collaborative Innovation Center for Advanced Organic Chemical Materials Co-constructed by the Province and Ministry Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and College of Chemistry and Chemical EngineeringHubei UniversityWuhan 430062China School of Physics and Engineering ITMO UniversitySt.Petersburg197101Russia School of Materials Science and Engineering Hubei UniversityWuhan430062China Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing School of Mechanical and Automotive EngineeringKey Laboratory of Polymer Processing EngineeringMinistry of EducationSouth China University of TechnologyGuangzhou 510641China

Developing luminescent metal-organic frameworks(MOFs) capable of high-efficiency Fe^(3+)sensing has aroused great attraction in the fields of biology,chemistry,***,previous solvothermal methods are limited by organic solvent usage,time consuming,high pressure,and high-energy ***,we propose the waste-toMOF strategy towards the scale-up production of La-MOF nanoparticles through the ball milling of recycled poly(-ethylene terephthalate)(PET) bottles and La(NO_(3))_(3)·_(6)H_(2)*** goes on alkaline hydrolysis to form 1,4-benzenedicarboxylic acid sodium salt(Na_(2)BDC) and ethylene glycol by ball ***,BDC reacts with La^(3+)to form *** as-prepared La-MOF crystal nanoparticles possess a rod-like morphology with the size of few hundred ***,La-MOF nanoparticles display high selectivity and sensitivity for Fe^(3+)*** quenching constant and limit of detection are 5.29×10^(3)(mol·L^(-1))^(-1) and 0.147 μmol·L^(-1),respectively,thus surpassing many advanced Fe^(3+) *** to the result of density functional theory,the high Fe^(3+) detection performance of La-MOF is related to the complexing of Fe^(3+)with La-MOF,which leads to the gradual dissociation of the coordination bond between terephthalic acid and La^(3+).It is anticipated that the mechanochemistry milling-based wasteto-MOF strategy provides a new platform for the massive production of functional MOFs in a green manner.

关键词： Metal-organic framework Waste polyester Mechanochemistry milling Fluorescence sensor

Research on Electromagnetic Wave Absorption Based on Electrospinning Technology

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Chinese Journal of Chemistry 2024年第7期42卷 777-789页

作者： Baoding Li Jing Qiao Yue liu Haoyuan tian Wei liu Qilei Wu Zhou Wang Jiurong liu Zhihui Zeng Key Laboratoryfor Liquid-Solid StructuralEvolution and Processing of Materials Schoolof Materials Science and EngineeringShandong UniversityJinanShandong 250061China China North Industries Group 53rd Research Institute JinanShandong 250000China School of Mechanical Engineering Shandong UniversityJinanShandong 250061China Institute of Crystal Materials State Key Laboratory of Crystal MaterialsShandong UniversityJinanShandong 250100China Shenzhen Research Institute of Shandong University ShenzhenGuangdong 518057China Science and Technology on Electromagnetic Compatibility Laboratory China Ship Development and Design CentreWuhanHubei 430064China suzhou Research Institute of Shandong University SuzhouJiangsu215123China

At present,in order to overcome electromagnetic interference and prevent electromagnetic harm,the research of new and efficient electromagnetic wave absorbing materials has become the research focus in the field of materials *** one-dimensional structure can promote the impedance matching and attenuation characteristics of the absorbing ***,as an effective method to prepare nanofibers with high length-diameter ratio,has been widely concerned because it is suitable for struc-tural design of various *** this paper,the research progress and absorption properties of nano-fiber materials prepared by electrospinning combined with different processes are introduced.

关键词： Electromagnetic wave(EMW)absorbing Electrospinning Nanofiber Impedance matching Nanocomposite