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Photochromic radical states in 3D covalent organic frameworks with zyg topology for enhanced photocatalysis

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National Science Review 2024年第7期11卷 177-188页

作者： Tian-Tian Ma Guo-Zhang Huang Xiao-han Wang Yan liang run-han li Bin Wang Su-Juan Yao Jia-Peng liao Shun-li li Yong Yan Ya-Qian Lan School of Chemistry South China Normal University Department of Chemistry Guangdong Provincial Key Laboratory of Catalytic Chemistry Southern University of Science and Technology

Covalent-organic frameworks（COFs） with photoinduced donor-acceptor（D-A） radical pairs show enhanced photocatalytic activity in principle. However, achieving long-lived charge separation in COFs proves challenging due to the rapid charge recombination. Here, we develop a novel strategy by combining[6 + 4] nodes to construct zyg-type 3D COFs, first reported in COF chemistry. This structure type exhibits a fused Olympic-rings-like shape, which provides a platform for stabilizing the photoinduced D-A radical pairs. The zyg-type COFs containing catalytically active moieties such as triphenylamine and phenothiazine（PTZ） show superior photocatalytic production rates of hydrogen peroxide（H2O2）. Significantly, the photochromic radical states of these COFs show up to 400% enhancement in photocatalytic activity compared to the parent states, achieving a remarkable H2O2synthesis rate of 3324 μmol g-1h-1, which makes the PTZ-COF one of the best crystalline porous photocatalysts in H2O2production. This work will shed light on the synthesis of efficient 3D COF photocatalysts built on topologies that can facilitate photogenerating D-A radical pairs for enhanced photocatalysis.

关键词： 3D covalent-organic frameworks photochromic radical states donor and acceptor hydrogen peroxide photocatalysis

Green synthesis of bifunctional phthalocyanine-porphyrin COFs in water for efficient electrocatalytic CO2 reduction coupled with methanol oxidation

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National Science Review 2023年第11期10卷 160-170页

作者： Mi Zhang Jia-Peng liao run-han li Sheng-Nan Sun Meng Lu Long-Zhang Dong Pei Huang Shun-li li Yue-Peng Cai Ya-Qian Lan South China Normal University School of Chemistry

Electrocatalytic CO2reduction(ECR) coupled with organic oxidation is a promising strategy to produce high value-added chemicals and improve energy efficiency. However, achieving the efficient redox coupling reaction is still challenging due to the lack of suitable electrocatalysts. Herein, we designed two bifunctional polyimides-linked covalent organic frameworks(PI-COFs) through assembling phthalocyanine(Pc) and porphyrin(Por) by non-toxic hydrothermal methods in pure water to realize the above catalytic *** to the high conductivity and well-defined active sites with different chemical environments, Ni Pc-Ni Por COF performs efficient ECR coupled with methanol oxidation reaction(MOR)(Faradaic efficiency of CO(FECO) = 98.12%, partial current densities of CO(j CO) = 6.14 m A cm-2for ECR, FEHCOOH = 93.75%,j HCOOH = 5.81 m A cm-2for MOR at low cell voltage(2.1 V) and remarkable long-term stability).Furthermore, experimental evidences and density functional theory(DFT) calculations demonstrate that the ECR process mainly conducts on Ni Pc unit with the assistance of Ni Por, meanwhile, the MOR prefers Ni Por conjugating with Ni Pc. The two units of Ni Pc-Ni Por COF collaboratively promote the coupled oxidation-reduction reaction. For the first time, this work achieves the rational design of bifunctional COFs for coupled heterogeneous catalysis, which opens a new area for crystalline material catalysts.

关键词： hydrothermal synthesis phthalocyanine-porphyrin COFs bifunctional electrocatalysts electrocatalytic CO2 reduction methanol oxidation reaction

Simultaneously Improved Curing,Mechanical,Antioxidative Properties and Reduced ZnO Loading of Silica Filled NR Composites by Incorporation of Low-cost Crude Carbon Dots via Conventional Melt-milling Method

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Chinese Journal of Polymer Science 2024年第6期42卷 815-825页

作者： Chao-Ying Sun Hai-Jun Ji li-Wei li Hui Yang Xiao-Peng An Yi-Ping Chen Ming-Jian han Can Jiang li-Qun Zhang Peng Yu run-Guo Wang State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing100029China School of Materials Science and Engineering Wuhan Institute of TechnologyWuhan430205China

Rubbers or elastomers play an important role in hi-tech technology and civilian daily life because of their unique and strategical ***,the rubber additives are essential components for rubbers’practical ***,developing novel multifunctional additives has attracted increasing research *** this work,low-cost crude carbon dots(CCDs)were used as multifunctional additives for natural rubber/silica system(without any additional modification)through industrial compatible melt-mixing *** results revealed that the CCDs could disperse well in the NR/silica system,and they could not only endow the rubber compound with excellent anti-aging capability due to CCDs’radical scavenging activity because of their plenty of nitrogen-containing species,but also improve the curing rate and mechanical performance of the rubber ***,the CCDs could reduce the rolling resistance of the rubber composites(tanδvalue at 7%strain of the rubber composite could be decreased by 34%),which is promising for the application of energy-saving tire ***,the addition of CCDs could effectively reduce the ZnO dosage by at least 40%in the rubber composite without deteriorating its ***,this work provides valuable guidance to develop novel cheap yet effective additives for the elastomer.

关键词： Natural rubber Crude carbon dots Antioxidant ZnO reduction Vulcanization

Theoretical Mechanistic Study on Arylation of C(sp3)-H Bond Catalyzed by Nickel and Photoredox Catalysis

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Theoretical Mechanistic Study on Arylation of C(sp3)-H Bond ...

lignin-reinforced PVDF electrolyte for dendrite-free quasi-solid-state li metal battery

中国化学会·第十三届全国物理有机化学学术会议

作者： Shuang Wang run-han li Wei Guan Faculty of Chemistry Northeast Normal University

Selective functionalization of C-H bond has become an important approach to synthesize C-C ***,visible light mediated iridium/nickel dual catalysis has been developed to effectively construct the C-C bonds. However,there exists considerable controversy regarding many mechanistic subtleties in the reaction process.

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Rare Metals 2024年第3期43卷 1006-1016页

作者： Xin-Yang Chen Xue-Jie Gao han-Yan Wu Yu-Long liu Xiao-Fei Yang run-Cang Sun Center for lignocellulosic Chemistry and Biomaterials College of Light Industry and Chemical EngineeringDalian Polytechnic UniversityDalian116034China Division of Energy Storage Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023China School of Chemistry Northeast Normal UniversityChangchun130024China

Quasi-solid-state lithium metal batteries(QSSLMBs)assembled with polyvinylidene fluoride(PVDF)are a promising class of next-generation rechargeable batteries due to their safety,high energy density,and superior interfacial ***,PVDF has a series of inherent drawbacks such as low ionic conductivity,ease of crystallization,and hydrophobic character that leading to poor cell *** tackle these issues,a lignin-reinforced PVDF electrolyte is proposed in this work to solve these drawbacks of PVDF and enhance the comprehensive performance of *** lithophilic polar groups of lignin can promote uniform deposition of li on the *** with the improved mechanical properties can efficiently prevent li dendrites penetration through the *** addition,more active sites provided by lignin can also enhance li^(+)transport and lead to a faster electrochemical reaction *** from the ingenious design,li symmetric cells with 5%lignin-PVDF quasi-solid-state electrolyte can operate for 900 h at a high current density/capacity of 5 mA·cm^(-2)/5 mAh·cm^(-2),while shortcircuiting occurs after 56 h for the counterpart(pure PVDF).Moreover,a full cell of li/5%lignin-PVDF/LFP cell demonstrates a high capacity of 96.2 mAh·g^(-1)after 2000 cycles at 10 *** work is expected to open up promising opportunities to develop other high-energy/power-density QSSLMBs.

关键词： Quasi-solid-state electrolyte lignin PVDF Dendrite-free li metal battery

Isomeric fluorescence sensors for wide range detection of ionizing radiations

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Defence Technology（防务技术） 2024年第4期34卷 247-257页

作者： Jimin han Tianyu Yang li Yang Yuanjian li State Key Laboratory of Explosion Science and Technology of China Beijing Institute of TechnologyBeijing 100081China Chongqing Innovation Center Beijing Institute of TechnologyChongqing 401120China

In order to achieve a wider range of ionizing radiations detection,novel fluorescence sensing materials have been developed that utilize the fluorescence enhancement phenomenon caused by the intramolecular photoinduced electron transfer(PET)*** perylene diimide isomers PDI-P and PDI-B were designed and synthesized,and their molecular structures were characterized by high-resolution Fourier transform mass spectrometry(HRMS),nuclear magnetic resonance hydrogen and carbon spectroscopy(~1H and~(13)C NMR).The interaction between ionizing radiation and fluorescent molecules was simulated by HCl *** results show that combining PDIs and HCl can improve fluorescence through the retro-PET *** the similarities in chemical structures,the fluorescent enhancement multiple of PDI-B with aromatic amine as electron donor is much higher than that of PDI-P with alkyl *** the direct irradiation experiments of ionizing radiation,the emission enhancement multiples of PDI-P and PDI-B are 2.01 and 45.4,***,density functional theory(DFT)and time-dependent density functional theory(TDDFT)calculations indicate that the HOMO and HOMO-1 energy ranges of PDI-P and PDI-B are 0.54 e V and 1.13 e V,respectively.A wider energy range has a stronger driving force on electrons,which is conducive to fluorescence *** femtosecond transient absorption spectroscopy(fs-TAS)and transient fluorescence spectroscopy(TFS)tests show that PDI-B has shorter charge separation lifetime and higher electron transfer rate *** both isomers can significantly reduce LOD during PET process,PDI-B with aromatic amine has a wider detection range of 0.118—240 Gy due to its larger emission enhancement,which is a leap of three orders of *** breaks through the detection range of gamma radiation reported in existing studies,and provides theoretical support for the further study of sensitive and effective new materials for ionizing radiation dete

关键词： Perylene imide Intramolecular PET Ionizing radiation detection Fluorescence sensor Isomers

Simulation study on the security of consensus algorithms in DAG-based distributed ledger

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Frontiers of Computer Science 2024年第3期18卷 171-182页

作者： Shuzhe li Hongwei XU Qiong li Qi han Faculty of Computing Harbin Institute of TechnologyHarbin 150001China

Due to the advantages of high volume of transactions and low resource consumption,Directed Acyclic Graph(DAG)-based Distributed Ledger Technology(DLT)has been considered a possible next-generation alternative to ***,the security of the DAG-based system has yet to be comprehensively *** at verifying and evaluating the security of DAG-based DLT,we develop a Multi-Agent based IOTA Simulation platform called *** MAIOTASim,we model honest and malicious nodes and simulate the configurable network environment,including network topology and *** double-spending attack is a particular security issue related to *** perform the security verification of the consensus algorithms under multiple double-spending attack *** simulations show that the consensus algorithms can resist the parasite chain attack and partially resist the splitting attack,but they are ineffective under the large weight *** take the cumulative weight difference of transactions as the evaluation criterion and analyze the effect of different consensus algorithms with parameters under each attack ***,MAIOTASim enables users to perform largescale simulations with multiple nodes and tens of thousands of transactions more efficiently than state-of-the-art ones.

关键词： distributed ledger IOTA Multi-Agent system simulation

Flocking Effects of the Stochastic Cucker-Smale System with Noise

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Journal of Systems Science & Complexity 2024年第5期37卷 1978-1994页

作者： han Ning GE Bin li lin School of Mathematical Sciences Harbin Engineering University

In this paper, the flocking behavior of a Cucker-Smale model with a leader and noise is studied in a finite time. The authors present a Cucker-Smale system with two nonlinear controls for a complex network with stochastic synchronization in probability. Based on the finite-time stability theory of stochastic differential equations, the sufficient conditions for the flocking of stochastic systems in a finite time are obtained by using the Lyapunov function method. Finally, the numerical simulation of the particle system is carried out for the leader and noise, and the correctness of the results is verified.

关键词： Cucker-Smale model flocking behavior leader noise

Analysis and Design of Time-Delay Impulsive Systems Subject to Actuator Saturation

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 196-204页

作者： Chenhong Zhu Xiuping han Xiaodi li IEEE the School of Mathematics and Statistics Shandong Normal UniversityJi'nan 250014China the Center for Control and Engineering Computation Shandong Normal UniversityJi'nan 250014China

This paper investigates the exponential stability and performance analysis of nonlinear time-delay impulsive systems subject to actuator saturation. When continuous dynamics is unstable, under some conditions, it is shown that the system can be stabilized by a class of saturated delayed-impulses regardless of the length of input delays. Conversely, when the system is originally stable, it is shown that under some conditions, the system is robust with respect to sufficient small delayed-impulses. Moreover, the design problem of the controller with the goal of obtaining a maximized estimate of the domain of attraction is formulated via a convex optimization problem. Three examples are provided to demonstrate the validity of the main results.

关键词： Delayed impulses impulsive control impulsive disturbance nonlinear systems saturation