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Science China Chemistry 2024年第4期67卷 1311-1315页

作者： Wu Li Daohong Liao Yougui Li Guifu si Changle Chen School of Chemistry and Chemical Engineering Hefei University of TechnologyHefei 230009China Key Laboratory of Precision and Intelligent Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

The development of degradable and recyclable polymers is an attractive strategy to tackle the post-consumption pollution issue of commercial ***-acyclic monomers metathesis polymerization(CAMMP)has been recently reported to produce degradable thermoset,thermoplastic and elastomeric polymers,and their degradability is enabled with addition of various *** this contribution,we demonstrate that the utilization of diene comonomers containing photodegradable moiety can give access to thermoset and thermoplastic materials bearing photo-degradation *** copolymerization of a series easily accessible diene comonomers bearing photodegradable ortho-nitrobenzyl moieties with dicyclopentadiene(DCPD)or cyclooctene(COE)leads to the formation of photodegradable p DCPD thermosets and p COE thermoplastic polymers with mechanical properties comparable to their non-degradable *** importantly,their photo-degradation properties can be efficiently tuned with the addition of ultraviolet absorber during in-situ polymerization.

关键词： metathesis polymerization photodegradable polydicyclopentadiene polyethylene-like materials

Lithiophilic Li-si alloy-solid electrolyte interface enabled by high-concentration dual salt-reinforced quasi-solid-state electrolyte

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Journal of Energy Chemistry 2024年第8期95卷 216-230,I0005页

作者： Yuanxing Zhang ling Zhang Zhiguang Zhao Yuxiang Zhang Jingwen Cui Chengcai Liu Daobin Mu Yuefeng Su Borong Wu Feng Wu School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Chongqing Innovation Center Beijing Institute of TechnologyChongqing 401120China Collaborative Innovation Center of Electric Vehicles in Beijing Beijing 100081China

Solid polymer electrolytes(SPEs)are urgently required to achieve practical solid-state lithium metal batteries(LMBs)and lithium-ion batteries(LIBs),Herein,we proposed a mechanism for modulating interfacial conduction and anode interfaces in high-concentration SPEs by *** electrolyte exhibits superior ionic conductivity and remarkable interface compatibility with salt-rich clusters:(1)polymer-plastic crystal electrolyte(P-PCE,TPU-SN matrix)dissociates ion pairs to facilitate Li+transport in the electrolyte and regulates Li^(+)diffusion in the *** crosslinking structure of the matrix compensates for the loss of mechanical strength at high-salt concentrations;(2)dual-anion TFsi^(-)_(n)-DFBOP^(-)_(m)in the Li^(+)solvation sheath facilitates facile Li^(+)desolvation and formation of salt-rich clusters and is conducive to the formation of Li conductive segments of TPU-SN matrix;(3)theoretical calculations indicate that the decomposition products of LiDFBOP form SEI with lower binding energy with LiF in the SN system,thereby enhancing the interfacial electrochemical redox kinetics of SPE and creating a solid interface SEI layer rich in *** a result,the optimized electrolyte exhibits an excellent ionic conductivity of9.31×10^(-4)S cm^(-1)at 30℃and a broadened electrochemical stability up to 4.73 *** designed electrolyte effectively prevents the formation of Li dendrites in Li symmetric cells for over 6500 h at0.1 mA cm^(-2).The specific Li-si alloy-solid state half-cell capacity shows 711.6 mAh g^(-1)after 60 cycles at 0.3 A g^(-1).Excellent rate performance and cycling stability are achieved for these solid-state batteries with Li-si alloy anodes and NCM 811 *** 811‖Prelithiated silicon-based anode solid-state cell delivers a discharge capacity of 195.55 mAh g^(-1)and a capacity retention of 97.8%after 120 *** 811‖Li solid-state cell also delivers capacity retention of 84.2%after 450 cycles.

关键词： Prelithiation Li-si alloy anode Solid-state electrolyte SEI layer

RFFsNet-SEI:a multidimensional balanced-RFFs deep neural network framework for specific emitter identification

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Journal of Systems Engineering and Electronics 2024年第3期35卷 558-574,F0002页

作者： FAN Rong si Chengke HAN Yi WAN Qun School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Institute of Electronic and Electrical Engineering Civil Aviation Flight University of ChinaGuanghan 618307China

Existing specific emitter identification(SEI)methods based on hand-crafted features have drawbacks of losing feature information and involving multiple processing stages,which reduce the identification accuracy of emitters and complicate the procedures of *** this paper,we propose a deep SEI approach via multidimensional feature extraction for radio frequency fingerprints(RFFs),namely,***,we extract multidimensional physical RFFs from the received signal by virtue of variational mode decomposition(VMD)and Hilbert transform(HT).The physical RFFs and I-Q data are formed into the balanced-RFFs,which are then used to train *** introducing model-aided RFFs into neural network,the hybrid-driven scheme including physical features and I-Q data is *** improves physical interpretability of ***,since RFFsNet-SEI identifies individual of emitters from received raw data in end-to-end,it accelerates SEI implementation and simplifies procedures of ***,as the temporal features and spectral features of the received signal are both extracted by RFFsNet-SEI,identification accuracy is ***,we compare RFFsNet-SEI with the counterparts in terms of identification accuracy,computational complexity,and prediction *** results illustrate that the proposed method outperforms the counterparts on the basis of simulation dataset and real dataset collected in the anechoic chamber.

关键词： specific emitter identification(SEI) deep learning(DL) radio frequency fingerprint(RFF) multidimensional feature extraction(MFE) variational mode decomposition(VMD)

High-entropy design boosts dielectric energy storage

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Rare Metals 2024年第8期43卷 4013-4015页

作者： Qiu-Ying Xia He Zhu si Lan Yang Ren Herbert Gleiter Institute of Nanoscience School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China Department of Physics City University of Hong KongHong Kong999077China

Dielectric capacitors are vital for advanced electronic and electrical power systems due to their impressive power density and ***,a persistent challenge has been enhancing their energy densities while maintaining high *** in Science,a novel high-entropy design for relaxor ferroelectric materials has been proposed,promising significant improvements in both energy density and efficiency for multilayer dielectric ceramic *** the crucial role of high-entropy design in energy storage materials and devices,this highlight focuses on interpreting the progress and significance of this innovative work.

关键词： ceramic dielectric energy

Molecular dynamics study of hydrogen-induced cracking behavior of ferrite–pearlite gas transmission pipeline steel

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Journal of Iron and Steel Research International 2024年第2期31卷 488-500页

作者： Tao-long Xu si-han Guo Gong-zhen He Hao-yu Han Petroleum Engineering School Southwest Petroleum UniversityChengdu610500SichuanChina sichuan East Gas Transmission Sales Center of sinopec Natural Gas Branch Wuhan430074HubeiChina

Hydrogen embrittlement of pipelines depends on the hydrogen-induced cracking behavior of the pipeline steel *** on molecular dynamics analysis,the ferrite–cementite(α-Fe/Fe3C)lamellar atomic structure with the Bagaryatskii orientation relationship was established,and stepwise relaxation of the conjugate gradient energy minimization and constant-temperature and constant-pressure relaxation were performed under NPT(the isothermal–isobaric)*** mechanical property curves of theα-Fe/Fe3C models were obtained under different cementite terminal plane structures,and the evolution of the atomic structure was analyzed in *** addition,the influence of different hydrogen concentrations,different temperatures,different strain rates,changes in voids,and different micro-degrees of freedom on the deformation and failure mechanism of the model was investigated,aiming to provide a reliable way to explore the micro-mechanism of macro-cracking behavior of pipeline steel.

关键词： Ferrite-cementite lamellar structure Pipeline steel Failure mechanism Crack propagation Molecular dynamics

Numerical and theoretical study of large-scale failure of strata overlying sublevel caving mines with steeply dipping discontinuities

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1799-1815页

作者： Kaizong Xia Zhiwei si Congxin Chen Xiaoshuang Li Junpeng Zou Jiahao Yuan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China School of Urban Construction Changzhou UniversityChangzhou 213164China Faculty of Engineering China University of Geosciences(Wuhan)Wuhan 430074China

The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical ***,an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium *** results show the following:(1)surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics,and(2)the behavior of the strata as they fail exhibits superimposition ***,failure first occurs in certain superimposed strata slightly far from the ***,with the constant downward excavation of the orebody,the superimposed strata become damaged both upwards away from and downwards toward the *** process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the *** deep fracture plane generally makes an angle of 12°-20°with the normal to the steeply dipping *** effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than *** strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling ***,the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure,in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever *** taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum,the failure scope of the strata(and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving)can be obtained via iterative computations from the ke

关键词： sublevel caving mines universal distinct element code(UDEC)numerical approach large-scale ground movement steeply dipping superimposed cantilever beam toppling failure

Time-lagged Effects of the Spring Atmospheric Heat Source over the Tibetan Plateau on Summer Precipitation in Northeast China during 1961–2020:Role of Soil Moisture

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Advances in Atmospheric Sciences 2024年第8期41卷 1527-1538页

作者： Yizhe HAN Dabang JIANG Dong si Yaoming MA Weiqiang MA Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000China National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes Dingri 858200China Kathmandu Center of Research and Education Chinese Academy of SciencesBeijing 100101China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakistan

The spring atmospheric heat source(AHS)over the Tibetan Plateau(TP)has been suggested to affect the Asian summer monsoon and summer precipitation over South ***,its influence on the summer precipitation in Northeast China(NEC)remains *** connection between spring TP AHS and subsequent summer precipitation over NEC from 1961 to 2020 is analyzed in this *** illustrate that stronger spring TP AHS can enhance subsequent summer NEC precipitation,and higher soil moisture in the Yellow River Valley-North China region(YRVNC)acts as a *** spring,the strong TP AHS could strengthen the transportation of water vapor to East China and lead to excessive rainfall in the ***,soil moisture increases,which regulates local thermal conditions by decreasing local surface skin temperature and sensible *** to the memory of soil moisture,the lower spring sensible heat over the YRVNC can last until mid-summer,decrease the land–sea thermal contrast,and weaken the southerly winds over the East Asia–western Pacific region and convective activities over the South China Sea and tropical western *** modulates the East Asia–Pacific teleconnection pattern,which leads to a cyclonic anomaly and excessive summer precipitation over NEC.

关键词： Tibetan Plateau atmospheric heat source Northeast China summer precipitation soil moisture

Quantification of perfluorinated compounds in atmospheric particulate shows potential connection with environmental event

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Journal of Environmental Sciences 2024年第2期136卷 237-247页

作者： Hua Tang Ying Wang Shengling si Hongli Li David Da Yong Chen National Institute of Metrology 18 BeisanhuandongluChaoyang DistrictBeijing 100029China School of Chemistry and Materials Science Nanjing Normal UniversityNanjing 210023China si chuan Zhong Ce Biao Wu Technology Co.Ltd. Sichuan 610052China Department of Chemistry University of British ColumbiaVancouver V6T 1Z1BCCanada

A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce the high matrix background and avoid contamination from commonly used multiple sample pretreatment *** effective sorbent was selected to purify the PFCs during SPLE,followed by liquid chromatography-tandem mass spectrometry(LC–MS/MS),for quantification of *** affecting the SPLE efficiency,including temperature,static extraction time,and number of extraction cycles used,were *** optimum conditions were found to be 120℃,10 min,and 3 cycles,***-MS/MS method was developed to obtain the optimal sensitivity specific to *** method detection limits(MDLs)were 0.006 to 0.48 ng/g for the PFCs studied and the linear response range was from 0.1 to 100 ng/*** ensure accurate values were obtained,each step of the experiment was evaluated and controlled to prevent *** optimized method was tested by performing spiking experiments in natural particulate matter matrices and good rates of recovery and reproducibility were obtained for all target ***,the method was successfully used to measure 16 PFCs in the APM samples collected in Beijing over five years from 2015 to *** is observed that some PFCs follow the trend of total PFC changes,and can be attributed to the environment influencing events and policy enforcement,while others don't seem to change as much with time of the year or from year to year.

关键词： Selective pressurized liquid extraction Liquid chromatography-mass spectrometry Perfluorinated compounds Atmospheric particulate matter Pollution control

Extreme value theory applied to the auroral electrojet indices

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Earth and Planetary Physics 2024年第2期8卷 375-381页

作者： si Chen Hong Yuan Yong Wei Guang Yang FengZheng Yu Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The study of extreme weather and space events has gained paramount importance in modern society owing to rapid advances in high *** and describing exceptional occurrences plays a crucial role in making decisive assessments of their potential impact on technical,economic,and social aspects in various *** research focuses on analyzing the hourly values of the auroral electrojet(AE)geomagnetic index from 1957 to 2019 by using the peak over threshold method in extreme value *** fitting the generalized Pareto distribution to extreme AE values,shape parameter indices were derived,revealing negative values that establish an upper bound for this time ***,it became evident that the AE values had reached a plateau,suggesting that extreme events exceeding the established upper limit are *** a result,although the need for diligent precautions to mitigate the consequences of such extreme events persists,surpassing the upper limit of AE values becomes increasingly *** is also possible to observe an aurora in the middle-and low-latitude regions during the maximum period of the AE index.

关键词： auroral electrojet indices extreme value theory extreme events

Analytical investigations of in situ stress inversion from borehole breakout geometries

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2375-2387页

作者： Zizhuo Xiang Taehyun Moon Joung Oh Guangyao si Ismet Canbulat School of Minerals and Energy Resources Engineering University of New South WalesSydneyNSW2052Australia HNTB Corporation 3505th Ave.58th FloorNew YorkNY10118USA

This study aims to investigate the feasibility of deriving in situ horizontal stresses from the breakout width and depth using the analytical ***-three breakout data with different borehole sizes were collected and three failure criteria were *** on the Kirsch equations,relatively accurate major horizontal stress(sH)estimations from known minor horizontal stress(sh)were achieved with percentage errors ranging from 0.33%to 44.08%using the breakout *** Mogi-Coulomb failure criterion(average error:13.1%)outperformed modified Wiebols-Cook(average error:19.09%)and modified Lade(average error:18.09%)failure ***,none of the tested constitutive models could yield reasonable sh predictions from known sH using the same approach due to the analytical expression of the redistributed stress and the nature of the constitutive *** consideration of this issue,the horizontal stress ratio(sH/sh)is suggested as an alternative input,which could estimate both sH and sh with the same level of ***,the estimation accuracies for both large-scale and laboratory-scale breakouts are comparable,suggesting the applicability of this approach across different breakout *** breakout depth,conformal mapping and complex variable method were used to calculate the stress concentration around the breakout tip,allowing the expression of redistributed stresses using binomials composed of sH and ***,analysis of the breakout depth stabilisation mechanism indicates that additional parameters are required to utilise normalised breakout depth for stress estimation compared to breakout *** parameters are challenging to obtain,especially under field conditions,meaning utilising normalised breakout depth analytically in practical applications faces significant challenges and remains infeasible at this ***,the normalised breakout depth should still be considered a critical input for any empirical and statistical stres

关键词： Borehole failure In situ stress estimation In situ horizontal stress ratio Conformal mapping Complex variable method Breakout stabilisation