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Persistent radical anion of perylene dianhydride:an emerging metal-free photocatalyst for near-infrared photocontrolled RAFT polymerization

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Science China Chemistry 2024年第2期67卷 677-686页

作者： Haitao Zhao guoqing bian Xiang Xu Weiwei He Lifen Zhang Zhenping Cheng State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials Jiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationSuzhou Key Laboratory of Macromolecular Design and Precision SynthesisCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou215123China

Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the persistent radical anion(PRA)(possessing the properties of both radical and anion) was developed for NIR photocontrolled reversible additionfragmentation chain transfer(RAFT) polymerization,enabling successful polymerization while gaining a deep insight into the mechanism of photo-induced electron transfer RAFT(PET-RAFT) polymerization.Different from the conventional and wellaccepted reductive quenching(RQ) pathway,in which the radical anion intermediates of PCs(PCs^(·-)) must be generated in an excited state(ES),here,the PRA(3,4,9,10-perylenetetracarboxylic dianhydride radical anion(PTCDA^(·-))) could generate conveniently in situ in the ground state(GS) and subsequently serve as highly efficient PC in the NIR region(740–850 nm).The successful implementation of this strategy elucidates the peculiar role played by light and the real way of electron transfer behaviors.In fact,the transfer of a single electron from PRA to chain transfer agent(CTA) and cleavage of the C–S bonds is a process from ES to GS,rather than always from GS(PCs^(·-)) to GS(CTA) in the RQ pathway as is well known to all.In addition,the excellent spatial-temporal control and powerful penetration ability of the NIR light were also confirmed by this PRAcatalyzed polymerization system.

关键词： photocatalyst persistent radical anion(PRA) near-infrared(NIR)light reversible-deactivation radical polymerization(RDRP) photo-induced electron transfer RAFT(PET-RAFT)polymerization

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Single thiolate replacement of metal nanoclusters

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Science China Chemistry 2024年第2期67卷 523-528页

作者： Ambreen Ambreen Yue Zhou Wanmiao Gu Qing You Liang Fang guoqing bian Nan Yan Nan Xia Zhikun Wu Key Laboratory of Materials Physics Anhui Key Laboratory of Nanomaterials and NanotechnologyInstitute of Solid State PhysicsHefei Institutes of Physical Science(HFIPS)Chinese Academy of SciencesHefei230031China University of Science and Technology of China Hefei230601China Institute of Physical Science and Information Technology Anhui UniversityHefei230601China

Surface thiolates play important roles in evincing the structures and properties of thiolated metal nanoclusters—one type of recently emerging inorganic-organic hybrids,and thus the thiolate substitution,especially single thiolate substitution,is highly desirable for subtly tailoring the structures and properties of metal nanoclusters.However,such a single-thiolate substituting is challenging,and its influence on the metal-metal and metal-sulfur bonds remains mysterious due to the absence of the singlethiolate-substituted structure.Here,we developed a combined method,concurrently synthesized the single-thiolate-substituted nanocluster and its parent nanocluster,and successfully resolved their structures by single crystal X-ray crystallography,which reveals that the single thiolate substitute has an obvious influence on the metal-metal and metal-sulfur bond lengths although it has no effect on the absorption profile.Interestingly,the metal-metal and metal-sulfur bonds show various thermal extensibility and even the negative thermal expansion phenomena of the Au–S bond were observed in the single-thiolate-substituted nanocluster.The bond length-related stability was also observed.Overall,this study highlights a novel synthesis method and offers novel structural insights and an in-depth structure-property correlation of thiolated metal nanoclusters.

关键词： metal nanoclusters single thiolate replacement thermal expansion stability intercluster interaction

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Optimal Bidding Strategy for PV and BESSs in Joint Energy and Frequency Regulation Markets Considering Carbon Reduction Benefits

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 427-439页

作者： Jing bian Yuheng Song Chen Ding Jianing Cheng Shiqiang Li guoqing Li Key Laboratory of Modern Power System Simulation and Control&Renewable Energy Technology Ministry of Education Northeast Electric Power UniversityJilin 132000China Datang Northeast Electric Power Test&Research Institute Co. Ltd.Changchun 130102China

Photovoltaic(PV)and battery energy storage systems(BESSs)are key components in the energy market and crucial contributors to carbon emission reduction targets.These systems can not only provide energy but can also generate considerable revenue by providing frequency regulation services and participating in carbon trading.This study proposes a bidding strategy for PV and BESSs operating in joint energy and frequency regulation markets,with a specific focus on carbon reduction benefits.A two-stage bidding framework that optimizes the profit of PV and BESSs is presented.In the first stage,the day-ahead energy market takes into account potential real-time forecast deviations.In the second stage,the real-time balancing market uses a rolling optimization method to account for multiple uncertainties.Notably,a real-time frequency regulation control method is proposed for the participation of PV and BESSs in automatic generation control(AGC).This is particularly relevant given the uncertainty of grid frequency fluctuations in the optimization model of the real-time balancing market.This control method dynamically assigns the frequency regulation amount undertaken by the PV and BESSs according to the control interval in which the area control error(ACE)occurs.The case study results demonstrate that the proposed bidding strategy not only enables the PV and BESSs to effectively participate in the grid frequency regulation response but also yields considerable carbon emission reduction benefits and effectively improves the system operation economy.

关键词： Photovoltaic(PV) battery energy storage system(BESS) energy market carbon market frequency regulation service bidding strategy

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A Lightweight Network with Dual Encoder and Cross Feature Fusion for Cement Pavement Crack Detection

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 255-273页

作者： Zhong Qu guoqing Mu Bin Yuan School of Computer Science and Technology Chongqing University of Posts and TelecommunicationsChongqing400065China School of Software Engineering Chongqing University of Posts and TelecommunicationsChongqing400065China

Automatic crack detection of cement pavement chiefly benefits from the rapid development of deep learning,with convolutional neural networks(CNN)playing an important role in this field.However,as the performance of crack detection in cement pavement improves,the depth and width of the network structure are significantly increased,which necessitates more computing power and storage space.This limitation hampers the practical implementation of crack detection models on various platforms,particularly portable devices like small mobile devices.To solve these problems,we propose a dual-encoder-based network architecture that focuses on extracting more comprehensive fracture feature information and combines cross-fusion modules and coordinated attention mechanisms formore efficient feature fusion.Firstly,we use small channel convolution to construct shallow feature extractionmodule(SFEM)to extract low-level feature information of cracks in cement pavement images,in order to obtainmore information about cracks in the shallowfeatures of images.In addition,we construct large kernel atrous convolution(LKAC)to enhance crack information,which incorporates coordination attention mechanism for non-crack information filtering,and large kernel atrous convolution with different cores,using different receptive fields to extract more detailed edge and context information.Finally,the three-stage feature map outputs from the shallow feature extraction module is cross-fused with the two-stage feature map outputs from the large kernel atrous convolution module,and the shallow feature and detailed edge feature are fully fused to obtain the final crack prediction map.We evaluate our method on three public crack datasets:DeepCrack,CFD,and Crack500.Experimental results on theDeepCrack dataset demonstrate the effectiveness of our proposed method compared to state-of-the-art crack detection methods,which achieves Precision(P)87.2%,Recall(R)87.7%,and F-score(F1)87.4%.Thanks to our lightweight crack detectionmodel,the parameter count of the mo

关键词： Shallow feature extraction module large kernel atrous convolution dual encoder lightweight network crack detection

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A bilateral heterogeneous graph model for interpretable job recommendation considering both reciprocity and competition

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Frontiers of Engineering Management 2024年第1期11卷 128-142页

作者： Xiaowei SHI Qiang WEI guoqing CHEN School of Economics and Management Tsinghua UniversityBeijing 100084China

Amidst the inefficiencies of traditional job-seeking approaches in the recruitment ecosystem, the importance of automated job recommendation systems has been magnified. However, existing models optimized to maximize user clicks for general product recommendations prove inept in addressing the unique challenges of job recommendation, namely reciprocity and competition. Moreover, sparse data on online recruitment platforms can further negatively impact the performance of existing job recommendation algorithms. To counteract these limitations, we propose a bilateral heterogeneous graph-based competition iteration model. This model comprises three integral components: 1) two bilateral heterogeneous graphs for capturing multi-source information from people and jobs and alleviating data sparsity, 2) fusion strategies for synthesizing attributes and preferences to produce mutually beneficial job matches, and 3) a competition-enhancing strategy for dispersing competition realized through a two-stage optimization algorithm. Augmented by granular attention mechanisms for enhanced interpretability, the model’s efficacy, competition dispersion, and interpretability are validated through rigorous empirical evaluations on a real-world recruitment platform.

关键词： job recommendation competition reciprocity interpretability

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Chemical vapor deposition for perovskite solar cells and modules

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Journal of Semiconductors 2024年第4期45卷 1-4页

作者： Zhihao Tao Yuxuan Song Baochang Wang guoqing Tong Liming Ding School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Metal halide perovskites are promising materials for solar cells because of high power conversion efficiency(PCE),tun-able bandgap,high defect tolerance,long carrier diffusion length,and low-cost fabrication[1-7].The PCE for perovskite solar cells(PSCs)reaches 26.14%for single-junction cells,29.1%for perovskite/perovskite tandem cells and 33.9%for perovskite/silicon tandem cells,being comparable to that for silicon and other thin-film solar cells[8-10].Perovskite solar cells have been made by solution methods including spin-coat-ing,blade coating and printing[11,12].

关键词： perovskite blade film

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Numerical Investigation of the Angle of Attack Effect on Cloud Cavitation Flow around a Clark-Y Hydrofoil

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2947-2964页

作者： Di Peng guoqing Chen Jiale Yan Shiping Wang College of Engineering Peking UniversityBeijing100871China College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China

Cavitation is a prevalent phenomenon within the domain of ship and ocean engineering,predominantly occurring in the tail flow fields of high-speed rotating propellers and on the surfaces of high-speed underwater vehicles.The re-entrant jet and compression wave resulting from the collapse of cavity vapour are pivotal factors contributing to cavity instability.Concurrently,these phenomena significantly modulate the evolution of cavitation flow.In this paper,numerical investigations into cloud cavitation over a Clark-Y hydrofoil were conducted,utilizing the Large Eddy Simulation(LES)turbulence model and the Volume of Fluid(VOF)method within the OpenFOAM framework.Comparative analysis of results obtained at different angles of attack is undertaken.A discernible augmentation in cavity thickness is observed concomitant with the escalation in attack angle,alongside a progressive intensification in pressure at the leading edge of the hydrofoil,contributing to the suction force.These results can serve as a fundamental point of reference for gaining a deeper comprehension of cloud cavitation dynamics.

关键词： Cloud cavitation re-entrant jet compression wave clark-Y hydrofoil

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Analysis of the Erosion-Corrosion Mechanism of the Air Cooler in a Hydrocracking Unit:A Numerical and Experimental Study

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China Petroleum Processing & Petrochemical Technology 2024年第1期26卷 126-138页

作者： Su guoqing Li Yan Guo Hongli Zhang Jianwen College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China

Corrosion leakages often occur in the air cooler of a hydrocracking unit,with the failure sites mainly located in the entrance area of the tubes.An analysis of the macroscopic morphology and corrosion products confirmed that the damage was caused by erosion-corrosion(E-C).Numerical and experimental methods were applied to investigate the E-C mechanism in the air cooler.Computational fluid dynamics(CFD)was used to calculate the hydrodynamic parameters of the air cooler.The results showed that there was a biased flow in the air cooler,which led to a significant increase in velocity,turbulent kinetic energy and wall shear within 0.2 m of the tube entrance.A visualization experiment was then performed to determine the principles of migration and transformation of multiphase flow in the air cooler tubes.Various flow patterns(pure droplet flow,mist flow,and annular flow)and their evolutionary processes were clearly depicted experimentally.The initiation mechanism and processes leading to the development of E-C in the air cooler were also determined.This study provided a comprehensive explanation for the E-C failures that occur in air coolers during operation.

关键词： air cooler hydrocracking unit erosion-corrosion simulation visualization experiment multiphase flow

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Local Torrential Rainfall Event within a Mei-Yu Season Mesoscale Convective System:Importance of Back-Building Processes

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Advances in Atmospheric Sciences 2024年第5期41卷 847-863页

作者： Honglei ZHANG Ming XUE Hangfeng SHEN Xiaofan LI guoqing ZHAI Zhejiang Institute of Meteorological Sciences Hangzhou 310017China Center for Analysis and Prediction of Storms and School of MeteorologyUniversity of OklahomaNormanOklahoma 73072USA Department of Atmospheric Science School of Earth SciencesZhejiang UniversityHangzhou 310027China Hangzhou Weather Bureau Hangzhou 310007China

An extreme rainfall event occurred over Hangzhou,China,during the afternoon hours on 24 June 2013.This event occurred under suitable synoptic conditions and the maximum 4-h cumulative rainfall amount was over 150 mm.This rainfall event had two major rainbands.One was caused by a quasi-stationary convective line,and the other by a backbuilding convective line related to the interaction of the outflow boundary from the first rainband and an existing low-level mesoscale convergence line associated with a mei-yu frontal system.The rainfall event lasted 4 h,while the back-building process occurred in 2 h when the extreme rainfall center formed.So far,few studies have examined the back-building processes in the mei-yu season that are caused by the interaction of a mesoscale convergence line and a convective cold pool.The two rainbands are successfully reproduced by the Weather Research and Forecasting(WRF)model with fourlevel,two-way interactive nesting.In the model,new cells repeatedly occur at the west side of older cells,and the backbuilding process occurs in an environment with large CAPE,a low LFC,and plenty of water vapor.Outflows from older cells enhance the low-level convergence that forces new cells.High precipitation efficiency of the back-building training cells leads to accumulated precipitation of over 150 mm.Sensitivity experiments without evaporation of rainwater show that the convective cold pool plays an important role in the organization of the back-building process in the current extreme precipitation case.

关键词： torrential rainfall back-building processes numerical simulation trigger mechanism convergence line convective cold pool

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Construction and properties of venlafaxine hydrochloride sustained release system based on hollow mesoporous silica microspheres

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Particuology 2024年第3期86卷 205-210页

作者： Chenjing Liang Lingling Shi Zhengguo Chen Lan Zhou Zhaoxia Zhang guoqing Zhang School of Materials Science and Engineering Zhejiang Sci-tech UniversityHangzhouChina College of Textile Science and Engineering Zhejiang Sci-tech UniversityHangzhouChina Zhejiang Provincial Innovation Center of Advanced Textile Technology ShaoxingChina

The aim of this work is to develop a venlafaxine hydrochloride sustained release system based on hollow mesoporous silica microspheres(HMSMs).HMSMs were innovatively prepared with tetraethyl silicate(TEOS)as the precursor and volatile n-heptane as a soft template.The obtained HMSMs show a well-defined hollow structure with an average size of 967 nm and pore volume of 0.85 cm^(3)/g,implying it is a potential drug carrier.Subsequently,venlafaxine hydrochloride(VF)was absorbed in the HMSMs with a content of 37.67% or so.The sustained release effect is further measured by the dissolution in-strument at 37℃ and 50 rpm in ultrapure water.The results showed that the HMSMs/VF system shows good sustained release properties compared with sustained release tablets with hydroxypropyl meth-ylcellulose as the main component.This HMSMs sustained release system appears to be a promising candidate for a sustained drug release.

关键词： Hollowmesoporous silica microspheres(HMSMs) Venlafaxine hydrochloride Drug loading Sustained release

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