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Advanced Potassium-Ion Batteries with High Areal Capacity

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CCS Chemistry 2024年第4期6卷 1011-1023页

作者： Song Chen jiang Zhong Hongli Deng Qiliang Wei Xiaohua shen Xinxin jia shengyang Li Qiusheng Zhang jian Zhu bingan Lu Weiyou Yang State Key Laboratory for Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringCollege of Materials Science and EngineeringCollege of Physics and ElectronicsHunan Key Laboratory of Two-Dimensional MaterialsEngineering Research Center of Advanced Catalysis of the Ministry of EducationHunan UniversityChangsha 410082 Institute of Micro/Nano Materials and Devices Ningbo University of TechnologyNingbo 315211

High areal capacity is one of the critically important points for potassium-ion batteries(PIBs)for practical applications,which relies on high areal-massloading electrodes operating at high reversible ***,it is remarkably restricted by the mechanical instability and sluggish charge transfer induced by the increased mass *** overcome such challenge,we report the rationally designed bimetallic selenides CoSe2/SnSe2 heterostructures confined in hierarchical carbon nanofibers(CSSe@CNFs),which enables the electrodes robust mechanical stability,enhanced electron transport,and reduced ion-diffusion energy barrier for facilitating reaction ***,an impressive areal mass loading up to 25.3 mg cm^(−2)was achieved,which endowed a high areal capacity of 7.58 mAh cm^(−2)for such a free-standing *** is stateof-the-art among the PIBs,exceeding that of today’s industry standard(∼3 mAh cm^(−2)for LIBs).Furthermore,it delivered long-term stability over 3700 cycles at high current density(∼2 mA cm^(−2),vs 1 mA cm^(−2)in LIBs).Moreover,the as-constructed full battery achieved a high energy density of 172.8 Wh kg-1 at 0.05 A g^(−1)with a satisfied cycle stability over 2000 cycles at 2 A g^(−1)and high reversibility with Coulombic efficiency of 100%;thus,signifying its bright future toward commercial application for advanced PIBs.

关键词： bimetal selenides heterostructure mass loading areal capacity potassium-ion battery

Synthesis of Organofluorine Compounds with Acylsilanes

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Chinese Journal of Chemistry 2024年第8期42卷 887-902页

作者： Youyuan Guo Gang Zhou Xiao shen The Institute for Advanced Studies Engineering Research Center of Organosilicon Compounds&MaterialsMinistry of EducationWuhan University299 Bayi RoadWuhanHubei430072 China

Comprehensive Summary,Organofluorine compounds are central in synthetic chemistry,medicinal chemistry and material *** this review,we summarize the investigations on the synthesis of organofluorine compounds with *** the non-fluorinated acylsilanes,the in situ generation of difluoroenoxysilanes from the reactions of the acylsilanes with trifluoromethylation reagents is the major pathway,leading to the facile preparation of variousα,α-*** the fluoroalkylacylsilanes,apart from the in situ generation of difluoroenoxysilanes through anion Brook rearrangement,radical Brook rearrangement of the photoexcited acylsilanes and the selective control of reactivities of the biradicals pave the way for the synthesis of a variety of organofluorine *** general,most of these reactions gave racemic products,and the asymmetric synthesis of organofluorine compounds with acylsilanes is still rare,which would be a future.

关键词： Acylsilanes Organofluorine compounds Brook rearrangement Radical rearrangement β-Fluoride elimination Asymmetric catalysis Photocatalysis Defluoroalkylation

Regulating microstructure and composition by carbonizing in-situ grown metal-organic frameworks on cotton fabrics for boosting electromagnetic wave absorption

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Nano Research 2024年第8期17卷 7290-7300页

作者： Jie Jin Hongsen Long Hu Liu Yan Guo Tiantian Bai Ben bin Xu Mohammed A.Amin Hua Qiu Mohamed H.Helal Chuntai Liu Changyu shen Zeinhom M.El-Bahy Zhanhu Guo State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentNational Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou 450002China China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410000China School of Electronic Engineering North China University of Water Resources and Electric PowerZhengzhou 450046China Complex Conditions of High-end Tire Technology Innovation Center Shuguang Rubber Industry Research&Design Institute Co.LtdGuilin 541004China Integrated Composites Lab Department of Mechanical and Civil EngineeringNorthumbria UniversityNewcastle Upon TyneNE18STUK Department of Chemistry College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Department of Chemistry Faculty of Arts and ScienceNorthern Border UniversityRafha 73213Saudi Arabia Department of Chemistry Faculty of ScienceAl-Azhar UniversityNasr City 11884CairoEgypt

High-temperature carbonized metal-organic frameworks(MOFs)derivatives have demonstrated their superiority for promising electromagnetic wave(EMW)absorbers,but they still suffer from limited EMW absorption capacity and narrow *** the advantage of microstructure and chemical composition regulation for the design of EMW absorber,hierarchical heterostructured MoS_(2)/CoS_(2)-Co_(3)O_(4)@cabonized cotton fabric(CF)(MCC@CCF)is prepared by growing ZIF-67 MOFs onto CF surface,chemical etching,and *** from the dual loss mechanism of magnetic-dielectric multicomponent carbonized MOFs,chemical etching and carbonization process can effectively introduce abundant micro-gap structure that can result in better impedance matching and stronger absorption capacity via internal reflection,doped heteroatoms(Mo,N,S)to supply additional dipolar polarization loss,and numerous heterointerfaces among MoS_(2),CoS_(2),Co_(3)O_(4),and CCF that produce promoted conduction loss and interfacial polarization ***,a minimal reflection loss of−52.87 dB and a broadest effective absorption bandwidth of 6.88 GHz were achieved via tunning the sample thickness and filler loading,showing excellent EMW absorption *** research is of great value for guiding the research on MOFs derivatives based EMW absorbing materials.

关键词： metal-organic frameworks hierarchical structure chemical etching sulfurization electromagnetic wave absorption

A Probing Model of Secret Key Generation Based on Channel Autocorrelation Function

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China Communications 2024年第6期21卷 163-175页

作者： Xia Enjun Hu binjie shen Qiaoqiao School of Electronic and Information Engineering South China University of TechnologyGuangzhou 510641China

Secret key generation(SKG)is a promising solution to the problem of wireless communications *** the first step of SKG,channel probing affects it *** there have been some probing schemes,there is a lack of research on the optimization of the probing *** study investigates how to optimize correlated parameters to maximize the SKG rate(SKGR)in the time-division duplex(TDD)***,we build a probing model which includes the effects of transmitting power,the probing period,and the dimension of sample *** on the model,the analytical expression of the SKGR is ***,we formulate an optimization problem for maximizing the SKGR and give an algorithm to solve *** conclude the SKGR monotonically increases as the transmitting power *** mathematical proofs are given in this *** the simulation results,increasing appropriately the probing period and the dimension of the sample vector could increase the SKGR dramatically compared to a yardstick,which indicates the importance of optimizing the parameters related to the channel probing phase.

关键词： channel autocorrelation function channel probing optimization problem physical layer security secret key generation

Theory and classification of mass extinction causation

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National Science Review 2024年第1期11卷 16-36页

作者： Thomas J.Algeo Jun shen State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences—Wuhan State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences—Wuhan Department of Geosciences University of Cincinnati

Theory regarding the causation of mass extinctions is in need of systematization, which is the focus of this contribution. Every mass extinction has both an ultimate cause, i.e. the trigger that leads to various climato-environmental changes, and one or more proximate cause(s), i.e. the specific climato-environmental changes that result in elevated biotic mortality. With regard to ultimate causes, strong cases can be made that bolide(i.e. meteor) impacts, large igneous province(LIP) eruptions and bioevolutionary events have each triggered one or more of the Phanerozoic Big Five mass extinctions, and that tectono-oceanic changes have triggered some second-order extinction events. Apart from bolide impacts, other astronomical triggers(*** flares, gamma bursts and supernova explosions) remain entirely in the realm of speculation. With regard to proximate mechanisms, most extinctions are related to either carbon-release or carbon-burial processes, the former being associated with climatic warming, ocean acidification, reduced marine productivity and lower carbonate δ13C values, and the latter with climatic cooling, increased marine productivity and higher carbonate δ13C values. Environmental parameters such as marine redox conditions and terrestrial weathering intensity do not show consistent relationships with carbon-cycle *** this context, mass extinction causation can be usefully classified using a matrix of ultimate and proximate factors. Among the Big Five mass extinctions, the end-Cretaceous biocrisis is an example of a bolide-triggered carbon-release event, the end-Permian and end-Triassic biocrises are examples of LIP-triggered carbon-release events, and the Late Ordovician and Late Devonian biocrises are examples of bioevolution-triggered carbon-burial events. Whereas the bolide-impact and LIP-eruption mechanisms appear to invariably cause carbon release, bioevolutionary triggers can result in variable carbon-cycle changes, e.g. carbon burial durin

关键词： biocrisis ultimate cause proximate cause bolide large igneous province bioevolutionary event

Highlights of mainstream solar cell efficiencies in 2023

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Frontiers in Energy 2024年第1期18卷 8-15页

作者： Wenzhong shen Yixin ZHAO Feng LIU Institute of Solar Energy and Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education)School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China School of Environmental Science and Engineering and Frontiers Science Center for Transformative MoleculesShanghai Jiao Tong UniversityShanghai 200240China School of Chemistry and Chemical Engineering and Frontiers Science Center for Transformative MoleculesShanghai Jiao Tong UniversityShanghai 200240China

This article continues our highlights last two years[1,2]on the highest independently confirmed mainstream(silicon,perovskite,and organic)solar cell efficiencies in *** world record power conversion efficiency(PCE)of the single-junction silicon and perovskite/silicon tandem solar cells has reached over 27%and close to 34%,respectively,in *** have also witnessed the rapid mass-production development of the silicon passivating contact and silicon back contact solar cells,as well as further progress with perovskite solar cells(PSCs).

关键词： perovskite mainstream fir

Stability Investigation and Improvement for DC Cascade Systems with Simplified Impedance-based Stability Criterion

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1044-1052页

作者： Junbin Fang Zhikang Shuai Yang Li Zhibing Wang Xiangyang Wu Xia shen Z.John shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Renewable Energy Department of China Electric Power Research Institute Beijing 100192China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA IEEE

In DC distributed power systems(DPSs),the complex impedance interactions possibly lead to DC bus voltage oscillation or *** previous research,the stability analysis of DPSs is implemented based on mathematical analysis in control *** specific mechanisms of the instability of the cascade system have not been intuitively *** this paper,the stability analysis of DPSs based on the traditional Nyquist criterion is simplified to the resonance analysis of the seriesconnected port impedance(Z=R+jX)of source and load *** reveals that the essential reason for impedance instability of a DC cascade system is that the negative damping characteristic(R<0)of the port the overall impedance amplifies the internal resonance source at reactance zero-crossing *** simplified stability criterion for DC cascade systems can be concluded as:in the negative damping frequency ranges(R<0),there exists no zero-crossing point of the reactance component(i.e.,X=0).According to the proposed stability criterion,the oscillation modes of cascade systems are classified.A typical one is the internal impedance instability excited by the negative damping,and the other one is that the external disturbance amplified by negativity in a low stability ***,the impedance reshaping method for stability improvement of the system can be further *** validity of the simplified criterion is verified theoretically and experimentally by a positive damping reshaping method.

关键词： DC cascaded system,impedance model impedance reconstruction stability criterion

Recent Advances in Enantioselective Reactions of Terminal Unactivated Alkenes

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Chinese Journal of Chemistry 2024年第7期42卷 760-776页

作者： Qihang Guo Xuzhong shen Zhan Lu Centerof ChemistryforFrontier Technologies Departmentof ChemistryZhejiang UniversityHangzhouZhejiang 310058China ZJU-Hangzhou Global Scientific and Technological Innovation Center HangzhouZhejiang 311215China College of Chemistry Zhengzhou UniversityZhengzhouHenan 450001China

α-Olefins as aliphatic terminal alkenes could be obtained easily from numerous contemporary synthetic reactions as well as petro-chemical industry,and also found in natural *** to the alkenes attaching the directing groups or activating group,the catalytic asymmetric reaction of unactivated terminal alkenes presents great challenges due to the weak electron effect and small steric hindrance *** review mainly summarizes the latest progress of the asymmetric reaction of unactivated terminal olefins since 2016.

关键词： Asymmetric catalysis Terminal unactivated alkenes Hydrofunctionalization Difunctionalization Metal-catalyzed

Analytical computation of magnetic field in coil-dominated superconducting quadrupole magnets based on racetrack coils

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Nuclear Science and Techniques 2024年第4期35卷 119-135页

作者： Chuang shen Ying-Shun Zhu Fu-San Chen China Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of Sciences1 Zhongziyuan RoadDongguan 523000China Institute of High Energy Physics Chinese Academy of Sciences19B Yuquan RoadBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and ***,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications *** with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical *** this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are *** analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current ***,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.

关键词： Superconducting quadrupole magnet Racetrack coil Multipole field Genetic algorithm Magnetic design