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Layered niobium carbide enabling excellent kinetics and cycling stability of li-Mg-B-H hydrogen storage material Layered niobium carbide enabling excellent kinetics

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Rare Metals 2024年第3期43卷 1153-1166页

作者： li-wen Lu Hui Luo Guang-Xu li Yun li Xin-Hua Wang Cun-Ke Huang Zhi-QiangLan wen-Zheng Zhou Jin Guo Mohammad Ismail Hai-Zhen liu Guangxi Novel Battery Materials Research Center of Engineering Technology Guangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationSchool of Physical Science and TechnologyGuangxi UniversityNanning530004China State Key Laboratory of Featured Metal Materials and life-Cycle Safety for Composite Structures Nanning530004China School of Mechanical and Electrical Engineering Quzhou College of TechnologyQuzhou324000China Department of Materials Science and Engineering Zhejiang UniversityHangzhou310027China Faculty of Ocean Engineering Technology and Informatics Universiti Malaysia Terengganu21030Kuala NerusTerengganuMalaysia Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin300071China

The li-Mg-B-H composite(2liBH_(4)+MgH_(2))has a high capacity of 11.4 wt%as a hydrogen storage ***,the slow kinetics and poor cycling stability severely restrict its practical *** this work,a layered Nb_(2)C MXene was first synthesized and then introduced to tailor the kinetics and cycling stability of the li-Mg-B-H *** milled 2liH+MgB_(2)composites were initially hydrogenated to obtain the 2liBH_(4)+MgH_(2)*** 2liBH_(4)+MgH_(2)+5wt%Nb_(2)C can release 9.0 wt%H_(2)in 30 min at 400℃,while it is only 2.7 wt%for the undoped 2liBH_(4)+MgH_(2).The dehydrogenation activation energies of MgH_(2)and liBH_(4)are 123 and 154 kJ·mol^(-1)respectively for the 5 wt%Nb_(2)C-doped composite,lower than the undoped composite(164 and 165 kJ·mol^(-1)).The 2liBH_(4)+MgH_(2)+5 wt%Nb_(2)C possesses excellent cycling stability,with the reversible capacity only slightly reduced from 9.4 wt%for the 1st cycle to 9.3 wt%for the 20th ***_(2)C keeps stable in the composite and acts as an efficient catalyst for the li-Mg-B-H *** is believed that both the layered structure and the active Nb element contribu te to the enhanced hydrogen storage performances of the li-Mg-B-H *** work confirms that the Nb_(2)C MXene with layered stru cture has a significant enhancing impact on the li-Mg-B-H hydrogen storage materials,which is different from the bulk NbC.

关键词： Hydrogen storage lithium borohydride Magnesium hydride Nb_(2)C MXene

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The embryonic period of ethnic medicine in Xinjiang

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History & Philosophy of Medicine 2022年第3期4卷 14-17页

作者： shu-wen li Department of Endocrinology western medicineInner Mongolia International Mongolian Medical HospitalHohhot 010000China

The industrious and brave Uyghurs have lived in the western regions for generations,creating and developing western region medicine while developing *** original medical treatment originated from the self-protection of primitive *** interactions with nature led to a spontaneous search for medicines and techniques and the realization that some plants could cure diseases,such as massage,pinching,kneading,rubbing,bone setting,and simple *** this period,superstition and sorcery were also accompanied in the process of curing *** is also the medical activity of the farming and nomadic peoples in Central Asia’s hinterland before the opening of the silk road.

关键词： Xinjiang region national medicine embryonic

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A high li-ion diffusion kinetics in multidimensional and compact-structured electrodes via vacuum filtration casting

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Journal of Energy Chemistry 2024年第6期93卷 368-376,I0010页

作者： Jieqiong li Ting Ouyang Lu liu shu Jiang Yongchao Huang M.-Sadeeq Balogun College of Materials Science and Engineering Hunan Joint International Laboratory of Advanced Materials and Technology for Clean EnergyHunan UniversityChangsha 410082HunanChina Institute of Environmental Research at Greater Bay Key Laboratory for Water Quality and Conservation of the Pearl River DeltaMinistry of EducationGuangzhou UniversityGuangzhou 510006GuangdongChina

Manufacturing process,diffusion co-efficient and areal capacity are the three main criteria for regulating thick electrodes for lithium-ion batteries(liBs).However,simultaneously regulating these criteria for liBs is desirable but remains a significant *** this work,niobium pentoxide(Nb_(2)O_(5))anode and lithium iron phosphate(liFePO_(4))cathode materials were chosen as the model materials and demonstrate that these three parameters can be simultaneously modulated by incorporation of micro-carbon fibers(MCF)and carbon nanotubes(CNT)with both Nb_(2)O_(5) and LFP via vacuum filtration *** as-prepared MNC-20 anode and MLC-20 cathode achieves high reversible areal capacity of≈5.4 m A h cm^(-2)@0.1 C and outstanding li-ion diffusion coefficients of≈10~(-8)cm~2 s~(-1)in the half-cell *** assembled MNC-20‖MLC-20 full cell liB delivers maximum energy and power densities of244.04 W h kg^(-1)and 108.86 W kg^(-1),*** excellent electrochemical properties of the asprepared thick electrodes can be attributed to the highly conductive,mechanical compactness and multidimensional mutual effects of the MCF,CNT and active materials that facilitates rapid li-ion diffusion ***,electrochemical impedance spectroscopy(EIS),symmetric cells analysis,and insitu Raman techniques clearly validates the enhanced li-ion diffusion kinetics in the present architecture.

关键词： Thick electrodes Carbon nanotubes li-ion diffusion co-efficient Vacuum filtration technique High areal capacity lithium-ion batteries

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Gradient sparsification for efficient wireless federated learning with differential privacy

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Science China(Information Sciences) 2024年第4期67卷 272-288页

作者： Kang WEI Jun li Chuan MA Ming DING Feng shu Haitao ZHAO wen CHEN Hongbo ZHU School of Electronic and Optical Engineering Nanjing University of Science and Technology Zhejiang Lab Key Laboratory of Computer Network and Information Integration(Southeast University) Ministry of Education Data61 Commonwealth Scientific and Industrial Research Organisation School of Information and Communication Engineering Hainan University School of Communications and Information Engineering Nanjing University of Posts and Telecommunications School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

Federated learning(FL) enables distributed clients to collaboratively train a machine learning model without sharing raw data with each other. However, it suffers from the leakage of private information from uploading models. In addition, as the model size grows, the training latency increases due to the limited transmission bandwidth and model performance degradation while using differential privacy(DP)protection. In this paper, we propose a gradient sparsification empowered FL framework with DP over wireless channels, to improve training efficiency without sacrificing convergence performance. Specifically, we first design a random sparsification algorithm to retain a fraction of the gradient elements in each client’s local model, thereby mitigating the performance degradation induced by DP and reducing the number of transmission parameters over wireless channels. Then, we analyze the convergence bound of the proposed algorithm, by modeling a non-convex FL problem. Next, we formulate a time-sequential stochastic optimization problem for minimizing the developed convergence bound, under the constraints of transmit power, the average transmitting delay, as well as the client’s DP requirement. Utilizing the Lyapunov drift-plus-penalty framework, we develop an analytical solution to the optimization problem. Extensive experiments have been implemented on three real-life datasets to demonstrate the effectiveness of our proposed algorithm. We show that our proposed algorithms can fully exploit the interworking between communication and computation to outperform the baselines, i.e., random scheduling, round robin, and delay-minimization algorithms.

关键词： federated learning differential privacy gradient sparsification Lyapunov drift convergence analysis

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A highly sensitive multiple-mode optical thermometer designed in Eu^(2+)/^(3+)and li^(+)co-doped polymorphism compound LaSc_(3)(BO_(3))_(4)

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Journal of Advanced Ceramics 2024年第6期13卷 821-833页

作者： Nan Yang Zhuo li Tingxia Zhou Ziwang Zhang wen Shi Yexiang Tong Jianxin Shi School of Chemistry IGCMESun Yat-sen UniversityGuangzhou 510006China MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry IGCMEThe Key Lab of Low-Carbon Chemistry&Energy Conservation of Guangdong ProvinceSun Yat-sen UniversityGuangzhou 510006China

Noncontact optical thermometers have attracted widespread attention,but existing problems such as single-mode and low-sensitivity thermometers still urgently need to be ***,a novel multiple-mode thermometer was designed for the polymorphism LaSc_(3)(BO_(3))_(4):Eu^(2+/3+),li^(+).X-ray diffraction(XRD)patterns revealed a slight transition betweenα-andβ-phases with the concentrations of the dopants,which is further proved by structure refinements and first-principles *** coexistence of Eu^(2+)and Eu^(3+)in the phosphors and their relative percentages were confirmed by X-ray absorption near-edge structure(XANES)*** from appropriate emissions from Eu^(2+)and Eu^(3+)without obvious energy transfer and their opposite changing trends with temperatures under 307 nm excitation,a triple-mode optical thermometer is obtained for this material within the temperature range of 150–450 *** highest sensitivities of 27.65,14.05,and 7.68%·K^(−1)are achieved based on two fluorescence intensity ratio(FIR)modes of Eu^(2+)and Eu^(3+)(5d–4f/^(5)D_(0)–^(7)F_(2,4))and the fluorescence lifetime(FL)mode of Eu^(2+),*** the best of our knowledge,the former is almost the highest in Eu^(2+)and Eu^(3+)co-doped *** results indicate that this material may be used as an excellent multiple-mode optical thermometer.

关键词： phase transition europium(Eu)ions multiple-mode optical thermometer thermal quenching properties fluorescence intensity ratio(FIR) fluorescence lifetime(FL)

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Atmospheric VOCs in an industrial coking facility and the surrounding area:Characteristics,spatial distribution and source apportionment

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Journal of Environmental Sciences 2024年第4期138卷 660-670页

作者： Meicheng wen Weiqiang Deng Jin Huang shu Zhang Qinhao lin ChaoWang Shengtao Ma Wanjun Wang Xin Zhang Guiying li Taicheng An Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health Guangdong Key Laboratory of Environmental Catalysis and Health Risk ControlInstitute of Environmental Health and Pollution controlGuangdong University of TechnologyGuangzhou 510006China Guangdong Engineering Technology Research Center for Photocatalytic Technology Integration and Equipment Guangzhou Key Laboratory of Environmental Catalysis and Pollution ControlSchool of Environmental Science and EngineeringGuangdong University of TechnologyGuangzhou 510006China Institute of Environmental Science Shanxi UniversityTaiyuan 030006China

Industrial coking facilities are an important emission source for volatile organic compounds(VOCs).This study analyzed the atmospheric VOC characteristics within an industrial coking facility and its surrounding *** concentrations of total VOCs(TVOCs)in the surrounding residential activity areas(R1 and R2),the coking facility(CF)and the control area(CA)were determined to be 138.5,47.8,550.0,and 15.0μg/m^(3),*** cold drum process and coking and quenching areas within the coking facility were identified as the main polluting *** spatial variation in VOCs composition was analyzed,showing that VOCs in the coking facility and surrounding areas were mainly dominated by aromatic compounds such as BTX(benzene,toluene,and xylenes)and naphthalene,with concentrations being negatively correlated with the distance from the coking facility(plity to surrounding residents and the development of strategies for VOC abatement.

关键词： Coking facility Volatile organic compounds Emission inventory Spatial distribution Source apportionment

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First-principles study on the diffusion behavior of Cs and I in Cr coating

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Nuclear Science and Techniques 2024年第6期35卷 177-188页

作者： shu-Ying lin Xiao-Jing li lin-Bing Jiang Xi-Jun Wu Hui-Qin Yin Yu Ma wen-Guan liu Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China School of Nuclear Science and Technology University of South ChinaHengyang 421001China

Cs and I can migrate through fuel-cladding interfaces and accelerate the cladding corrosion process induced by the fuel-cladding chemical *** coating has emerged as an important candidate for mitigating this chemical *** this study,first-principles calculations were employed to investigate the diffusion behavior of Cs and I in the Cr bulk and grain boundaries to reveal the microscopic interaction mitigation mechanisms at the fuel-cladding *** interaction between these two fission products and the Cr coating were studied systematically,and the Cs and I temperature-dependent diffusion coefficients in Cr were obtained using Bocquet’s oversized solute-atom model and Le Claire’s nine-frequency model,*** results showed that the Cs and I migration barriers were significantly lower than that of Cr,and the Cs and I diffusion coefficients were more than three orders of magnitude larger than the Cr self-diffusion coefficient within the temperature range of Generation-IV fast reactors(below 1000 K),demonstrating the strong penetration ability of Cs and ***,Cs and I are more likely to diffuse along the grain boundary because of the generally low migration barriers,indicating that the grain boundary serves as a fast diffusion channel for Cs and I.

关键词： First-principles calculation Fuel cladding chemical interaction Cr coating Fission product Diffusion Grain boundary

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Polyimide covalent organic frameworks as efficient solid-state li^(+) electrolytes

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Science China Chemistry 2024年第5期67卷 1647-1652页

作者： Xu liu Shi Wang Siqi liu Chengfang liu Xiangchun li Jian Wu Dazhi li Shihao Xu Chongyang liu wen-Yong Lai State Key Laboratory of Organic Electronics and Information Displays(SKLOEID) Institute of Advanced Materials(IAM)School of Chemistry and Life SciencesNanjing University of Posts&TelecommunicationsNanjing 210023China

Covalent organic frameworks(COFs) are attractive porous crystalline materials with extremely high stability, easy functionalization, and open channels, which are expected to be unique ion conductors/transporters in lithium ion batteries(liBs). Despite recent advances, low ion conductivity and low transference number, resulting in low charging/discharging rate, low energy density, and short battery life, are the main issues that limit their direct application as solid electrolytes in liBs. Here, we designed and synthesized a novel polyimide COF, namely, TAPA-PDI-COF, with abundant C=O groups, which has been successfully employed as high-performance solid electrolytes by doping TAPA-PDI-COF and succinonitrile(SN). Both the well-defined nanochannels of COFs and SN confined in the well-aligned channels restricted the free migration of anions, while C=O on COFs and CN groups of SN enhanced li^(+) transport, thus achieving a high ion conductivity of 0.102 m S cm^(-1)at 80 °C and a high lithium-ion transference number of 0.855 at room temperature. According to density functional theory(DFT)calculations, li-ion migration mainly adopted in-plane transport rather than the axial pathway, which may be due to the shorter hopping distances in the planar pathway. The results suggest an effective strategy for the design and development of all-solidstate ionic conductors for achieving high-performance liBs.

关键词： lithium ion batteries(liBs) covalent organic frameworks(COFs) solid-state ion conductors solid-state electrolytes ion conductivity

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Quenching and flow of charm and bottom quarks via semi-leptonic decay of D and B mesons in Pb+Pb collisions at the LHC

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Chinese Physics C 2024年第8期48卷 190-197页

作者： shu-Qing li wen-Jing Xing Shanshan Cao Guang-You Qin School of Physics and Electronic Engineering Jining UniversityQufu 273155China Institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics(MOE) Central China Normal UniversityWuhan 430079China

Heavy flavor particles provide important probes of the microscopic structure and thermodynamic properties of the quark-gluon plasma(QGP)produced in high-energy nucleus-nucleus *** studied the energy loss and flow of charm and bottom quarks inside the QGP via the nuclear modification factor(R_(AA))and elliptic flow coefficient(v_(2))of their decayed leptons in heavy-ion collisions at the *** dynamical evolution of the QGP was performed using the CLVisc(3+1)-dimensional viscous hydrodynamics model;the evolution of heavy quarks inside the QGP was simulated with our improved Langevin model that considers both collisional and radiative energy loss of heavy quarks;the hadronization of heavy quarks was simulated via our hybrid coalescence-fragmentation model;and the semi-leptonic decay of D and B mesons was simulated via *** the same spatial diffusion coefficient for charm and bottom quarks,we obtained smaller R_(AA) and larger v_(2) of charm decayed leptons than bottom decayed leptons,indicating stronger energy loss of charm quarks than bottom quarks inside the QGP within our current model setup.

关键词： quark-gluon plasma heavy-ion collisions jet quenching anisotropic flow heavy quark heavy flavor muon

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Photosynthetic response dynamics in the invasive species Tithonia diversifolia and two co-occurring native shrub species under fluctuating light conditions

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Plant Diversity 2024年第2期46卷 265-273页

作者： Ju li shu-Bin Zhang Yang-Ping li CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglunMengla 666303YunnanChina University of Chinese Academy of Sciences Beijing 100049China

To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native ***,few studies have compared the photosynthetic dynamics between invasive and native species during light *** compared photosynthetic induction,relaxation dynamics and leaf traits between the invasive species,Tithonia diversifolia and two native species,Clerodendrum bungei and Blumea balsamifera,in full-sun and shady *** photosynthetic dynamics and leaf traits differed among *** showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun ***,the slow induction response may be attributed to the longer stomatal length in *** had a significant effect on photosynthetic dynamics in *** and *** but not in *** shady habitat,*** had a faster photosynthetic induction response than in full-sun habitat,leading to a higher average stomatal conductance during photosynthetic induction in *** than in the two native *** contrast,*** had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat,resulting in higher carbon gain during photosynthetic ***,in both habitats,*** had an overall higher carbon gain during light fluctuations than the two native *** results indicated that *** can adopt more effective response strategies under fluctuating light environments to maximize carbon gain,which may contribute to its successful invasion.

关键词： Invasive plant Photosynthetic induction Photosynthetic relaxation Carbon gain Stomatal traits Tithonia diversifolia

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