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Reduction of unactivated alkyl chlorides enabled by light-induced single electron transfer

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Science China Chemistry 2024年第2期67卷 471-481页

作者： lei dai Zhao-Fei Zhang Xiang-Yu Chen School of Chemical Sciences University of the Chinese Academy of SciencesBeijing100049China Institute of Chemistry Chinese Academy of SciencesBeijing100190China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou256606China

Alkyl chlorides are abundant and easily accessible starting ***,due to the high reduction potentials associated with unactivated alkyl chlorides,achieving their single electron reduction remains a persistent *** challenge has spurred the exploration of efficient activation methods to overcome this *** recent years,photocatalysis has emerged as a mild and potent tool for the single electron reduction of unactivated alkyl chlorides,opening up new possibilities in this *** the rapid advancements in this area,a comprehensive review that provides a conceptual understanding of this emerging field,with a specific focus on reaction design and catalytic mechanisms,would be timely and highly ***,we present an overview of various synthetic techniques for photoinduced single electron reduction of unactivated alkyl ***,we also discuss the limitations of the present methods and future directions that lie ahead in this field.

关键词： photocatalysis unactivated alkyl chlorides single electron transfer radical reactions

Nb_(2)O_(5) nanocrystals decorated graphene composites as anode materials for high-performance dual-ion batteries

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Nano Research 2024年第3期17卷 1535-1541页

作者： lei Wang Fei Huang Guoyin Zhu Zhihui dai Jiangsu Collaborative Innovation Center of Biomedical Functional Materials Jiangsu Key Laboratory of Biofunctional MaterialsSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023China Institute of Advanced Materials and Flexible Electronics(IAMFE) School of Chemistry and Materials ScienceNanjing University of Information Science&TechnologyNanjing 210044China School of Chemistry and Molecular Engineering Nanjing Tech UniversityNanjing 211816China

Niobium oxide(Nb_(2)O_(5))is a promising material in photocatalytic,solar cell,electronic like electron field emitters,and especially lithium-ion batteries(LIBs)because of its adjustable morphologies,controllable crystal type,stable structure,and environmental ***,its low electrical conductivity lowers the rate performance and limits the practical applications in ***,we present a one-step solid-state synthesis of orthogonal Nb_(2)O_(5) nanocrystals/graphene composites(Nb_(2)O_(5)/G)as high-performance anode materials in *** from the nanoscale crystalline structure Nb_(2)O_(5) and highly-conductive graphene substrate,the as-prepared Nb_(2)O_(5)/G exhibits excellent electrochemical ***,a reversible structural phase transition between orthogonal Nb_(2)O_(5) and tetragonal Li1-xNbO_(2)(0

关键词： niobium oxide graphene anode dual-ion batteries graphite intercalation

A Denoiser for Correlated Noise Channel Decoding: Gated-Neural Network

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China Communications 2024年第2期21卷 122-128页

作者： Xiao Li Ling Zhao Zhen dai Yonggang lei School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Beijing Institute of Tracking and Telecommunications Technology BITTT

This letter proposes a sliced-gated-convolutional neural network with belief propagation(SGCNN-BP) architecture for decoding long codes under correlated noise. The basic idea of SGCNNBP is using Neural Networks(NN) to transform the correlated noise into white noise, setting up the optimal condition for a standard BP decoder that takes the output from the NN. A gate-controlled neuron is used to regulate information flow and an optional operation—slicing is adopted to reduce parameters and lower training complexity. Simulation results show that SGCNN-BP has much better performance(with the largest gap being 5dB improvement) than a single BP decoder and achieves a nearly 1dB improvement compared to Fully Convolutional Networks(FCN).

关键词： belief propagation channel decoding correlated noise neural network

Design of Protograph LDPC-Coded MIMO-VLC Systems with Generalized Spatial Modulation

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China Communications 2024年第3期21卷 118-136页

作者： dai Lin fang Yi Guan Yongliang Mohsen Guizani School of Information Engineering Guangdong University of TechnologyGuangzhou 51006China The State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an 710126China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore Department of Machine Learning Mohamed Bin Zayed University of Artificial Intelligence(MBZUAI)Abu DhabiUnited Arab Emirates

This paper investigates the bit-interleaved coded generalized spatial modulation(BICGSM) with iterative decoding(BICGSM-ID) for multiple-input multiple-output(MIMO) visible light communications(VLC). In the BICGSM-ID scheme, the information bits conveyed by the signal-domain(SiD) symbols and the spatial-domain(SpD) light emitting diode(LED)-index patterns are coded by a protograph low-density parity-check(P-LDPC) code. Specifically, we propose a signal-domain symbol expanding and re-allocating(SSER) method for constructing a type of novel generalized spatial modulation(GSM) constellations, referred to as SSERGSM constellations, so as to boost the performance of the BICGSM-ID MIMO-VLC ***, by applying a modified PEXIT(MPEXIT) algorithm, we further design a family of rate-compatible P-LDPC codes, referred to as enhanced accumulate-repeat-accumulate(EARA) codes,which possess both excellent decoding thresholds and linear-minimum-distance-growth property. Both analysis and simulation results illustrate that the proposed SSERGSM constellations and P-LDPC codes can remarkably improve the convergence and decoding performance of MIMO-VLC systems. Therefore, the proposed P-LDPC-coded SSERGSM-mapped BICGSMID configuration is envisioned as a promising transmission solution to satisfy the high-throughput requirement of MIMO-VLC applications.

关键词： bit-interleaved coded modulation generalized spatial modulation multiple-input multipleoutput protograph LDPC codes visible light communication

Bald Eagle Search Optimization Algorithm Combined with Spherical Random Shrinkage Mechanism and Its Application

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Journal of Bionic Engineering 2024年第1期21卷 572-605页

作者： Wenyan Guo Zhuolin Hou fang dai Xiaoxia Wang Yufan Qiang Department of Applied Mathematics School of ScienceXi'an University of TechnologyXian 710054ShaanxiChina

Over the last two decades,stochastic optimization algorithms have proved to be a very promising approach to solving a variety of complex optimization *** eagle search optimization(BES)as a new stochastic optimization algorithm with fast convergence speed has the ability of prominent optimization and the defect of collapsing in the local *** avoid BES collapse at local optima,inspired by the fact that the volume of the sphere is the largest when the surface area is certain,an improved bald eagle search optimization algorithm(INMBES)integrating the random shrinkage mechanism of the sphere is ***,the INMBES embeds spherical coordinates to design a more accurate parameter update method to modify the coverage and dispersion of the ***,the population splits into elite and non-elite groups and the Bernoulli chaos is applied to elite group to tap around potential solutions of the *** non-elite group is redistributed again and the Nelder-Mead simplex strategy is applied to each group to accelerate the evolution of the worst individual and the convergence process of the *** results of Friedman and Wilcoxon rank sum tests of CEC2017 in 10,30,50,and 100 dimensions numerical optimization confirm that the INMBES has superior performance in convergence accuracy and avoiding falling into local optimization compared with other potential improved algorithms but inferior to the champion algorithm and ranking *** three engineering constraint optimization problems and 26 real world problems and the problem of extracting the best feature subset by encapsulated feature selection method verify that the INMBES’s performance ranks first and has achieved satisfactory accuracy in solving practical problems.

关键词： Bald eagle search optimization algorithm Spherical coordinates Chaotic variation Simplex method Encapsulated feature selection

Ultrathin and flexible MXene-contained electromagnetic interference shielding composite paper designed with a protective hydrogel film

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Journal of Materials Science & Technology 2024年第2期169卷 199-208页

作者： Jiasheng Wei lei dai Ping He Meng Zhu Feng Jiang Zhaoxiang Zhou Guiqiang Fei Tingzhou lei College of Bioresources Chemical and Materials Engineering Shaanxi University of Science and TechnologyXi’an 710021China Key Laboratory of Eco-Textiles Ministry of EducationJiangnan UniversityWuxi 214122China Zhejiang Shunpu New Material Technology Co. LtdLongyou 324404China College of Chemistry and Chemical Engineering Shaanxi University of Science and TechnologyXi’an 710021China National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization Institute of Urban and Rural MiningChangzhou UniversityChangzhou 213164China

MXene-contained paper is a good choice to design ultrathin and flexible electromagnetic interference(EMI)shielding ***,the deficiencies in strength and stability of MXene-contained paper impede its practical ***,a composite paper was proposed to address the problems,in which a filter paper was modified with a three-layer structured surface via a facile layer-by-layer coating ***,the TEMPO-oxidized cellulose nanofibers(TOCN)/cationic starch(CS)/MXene gel layer and TOCN/MXene nacre structure layer ensured the good EMI shielding and mechanical performances of the composite paper,while the uppermost TOCN/CS hydrogel film layer mainly protected *** composite paper achieved an EMI SE of 40.3 dB at a thickness of merely 0.1894 mm(SE/t value of ca.212.8 dB mm^(−1),SSE/t values of ca.13216 dB cm 2 g^(−1))and the total MXene dosage was 20 g m^(−2).Its tensile strength could be up to 11.7 MPa while the original filter paper was 6.4 *** pieces of this composite papers could be easily packed together to attain an EMI SE of nearly 70 ***,the hydrogel film layer efficiently protected the MXene and maintained the EMI shielding performance of the composite paper when immersed in different liquids including water,HCl(1 M)and ethanol,due to the dense and compact structure of hydrogel film *** work provides a practical way to develop ultrathin,flexible and durable EMI shielding materials.

关键词： MXene Electromagnetic interference shielding Nanocellulose Hydrogel

Rockburst criterion and evaluation method for potential rockburst pit depth considering excavation damage effect

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1649-1666页

作者： Jinhao dai Fengqiang Gong lei Xu Engineering Research Center of Safety and Protection of Explosion & Impact of Ministry of Education (ERCSPEIME) Southeast UniversityNanjing211189China School of Civil Engineering Southeast UniversityNanjing211189China

Excavation-induced disturbances in deep tunnels will lead to deterioration of rock properties and formation of excavation damaged zone(EDZ).This excavation damage effect may affect the potential rockburst pit *** two diversion tunnels of Jinping II hydropower station for example,the relationship between rockburst pit depth and excavation damage effect is first *** results indicate that the rockburst pit depth in tunnels with severe damage to rock masses is relatively ***,the excavation-induced damage effect is characterized by disturbance factor D based on the Hoek-Brown criterion and wave velocity *** is found that the EDZ could be further divided into a high-damage zone(HDZ)with D=1 and weak-damage zone(WDZ),and D decays from one to zero *** this,a quantitative evaluation method for potential rockburst pit depth is established by presenting a three-element rockburst criterion considering rock strength,geostress and disturbance *** evaluation results obtained by this method match well with actual *** addition,the weakening of rock mass strength promotes the formation and expansion of potential rockburst *** potential rockburst pit depth is positively correlated with HDZ and WDZ depths,and the HDZ depth has a significant contribution to the potential rockburst pit depth.

关键词： Deep tunnel Rockburst Rockburst pit Excavation damage effect Hoek-Brown criterion

Enhancing Green Ammonia Electrosynthesis Through Tuning Sn Vacancies in Sn‑Based MXene/ MAX Hybrids

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Nano-Micro Letters 2024年第5期16卷 154-168页

作者： Xinyu dai Zhen‑Yi Du Ying Sun Ping Chen Xiaoguang Duan Junjun Zhang Hui Li Yang Fu Baohua Jia lei Zhang Wenhui fang Jieshan Qiu Tianyi Ma Key Laboratory for Green Synthesis and Preparative Chemistry of Advanced Materials of Liaoning Province College of ChemistryInstitute of Clean Energy ChemistryLiaoning UniversityShenyang 110036People’s Republic of China State Key Laboratory of Clean and Efficient Coal Utilization Taiyuan University of TechnologyTaiyuan 030024People’s Republic of China School of Chemistry and Chemical Engineering Anhui UniversityHefei 230601People’s Republic of China School of Chemical Engineering The University of AdelaideAdelaideSA 5005Australia State Key Laboratory of High‑Efficiency Utilization of Coal and Green Chemical Engineering College of Chemistry and Chemical EngineeringNingxia UniversityYinchuan 750021NingxiaPeople’s Republic of China School of Science RMIT UniversityMelbourneVIC 3000Australia Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640People’s Republic of China College of Chemical Engineering State Key Laboratory of Chemical Resource EngineeringBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China

Renewable energy driven N_(2) electroreduction with air as nitrogen source holds great promise for realizing scalable green ammonia ***,relevant out-lab research is still in its ***,a novel Sn-based MXene/MAX hybrid with abundant Sn vacancies,Sn@Ti_(2)CTX/Ti_(2)SnC–V,was synthesized by controlled etching Sn@Ti_(2)SnC MAX phase and demonstrated as an efficient electrocatalyst for electrocatalytic N2 *** to the synergistic effect of MXene/MAX heterostructure,the existence of Sn vacancies and the highly dispersed Sn active sites,the obtained Sn@Ti2CTX/Ti_(2)SnC–V exhibits an optimal NH_(3) yield of 28.4μg h^(−1) mg_(cat)^(−1) with an excellent FE of 15.57% at−0.4 V versus reversible hydrogen electrode in 0.1 M Na_(2)SO_(4),as well as an ultra-long ***,this catalyst represents a satisfactory NH3 yield rate of 10.53μg h^(−1) mg^(−1) in the home-made simulation device,where commercial electrochemical photovoltaic cell was employed as power source,air and ultrapure water as feed *** as-proposed strategy represents great potential toward ammonia production in terms of financial cost according to the systematic technical economic *** work is of significance for large-scale green ammonia production.

关键词： Green ammonia synthesis N2 electroreduction Renewable energy Sn MXene/MAX hybrid

Manipulating Nb-doped SrFeO_(3−δ)with excellent performance for proton-conducting solid oxide fuel cells

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Journal of Advanced Ceramics 2024年第5期13卷 579-589页

作者： Hailu dai Hongzhe Du Samir Boulfrad Shoufu Yu lei Bi Qinfang Zhang School of Materials Science and Engineering Yancheng Institute of TechnologyYancheng 224051China College of Science&Engineering Hamad Bin Khalifa UniversityDoha 34110Qatar School of Resource Environment and Safety Engineering University of South ChinaHengyang 421001China

Nb-doped SrFeO_(3−δ)(SFO)is used as a cathode in proton-conducting solid oxide fuel cells(H-SOFCs).First-principles calculations show that the SrFe0.9Nb0.1O_(3−δ)(SFNO)cathode has a lower energy barrier in the cathode reaction for H-SOFCs than the Nb-free SrFeO_(3−δ)*** experimental studies show that Nb doping substantially enhances the performance of the SrFeO_(3−δ)***,oxygen vacancies(VO)were introduced into SFNO using the microwave sintering method,further improving the performance of the SFNO *** mechanism behind the performance improvement owing to VO was revealed using first-principles calculations,with further optimization of the SFNO cathode achieved by developing a suitable wet chemical synthesis route to prepare nanosized SFNO *** method significantly reduces the grain size of SFNO compared with the conventional solid-state reaction method,although the solid-state reaction method is generally used for preparing Nb-containing *** a result of defect engineering and synthesis approaches,the SFNO cathode achieved an attractive fuel cell performance,attaining an output of 1764 mW·cm−2 at 700℃ and operating for more than 200 *** manipulation of Nb-doped SrFeO_(3−δ)can be seen as a“one stone,two birds”strategy,enhancing cathode performance while retaining good stability,thus providing an interesting approach for constructing high-performance cathodes for H-SOFCs.

关键词： SrFeO_(3−δ)-(SFO) cathode proton conductor solid oxide fuel cells(SOFCs)