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Doping suppresses lattice distortion of vacant quadruple perovskites to activate self-trapped excitons emission

Nano Research 2024年第4期17卷 3068-3078页

作者： Zhipeng Chen Fei Zhang Dongwen Yang Huifang Ji Xu Chen Di Wu Xinjian Li Yu Zhang Zhifeng Shi Key Laboratory of Materials Physics of Ministry of Education School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China State Key Laboratory on Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

The vacancy-ordered quadruple perovskite Cs_(4)CdBi_(2)Cl_(12),as a newly-emerging lead-free perovskite system,has attracted great research interest due to its excellent stability and direct band ***,the poor luminescence performance limits its application in light-emitting diodes(LEDs)and other ***,for the first time,an Ag^(+)ion doping strategy was proposed to greatly improve the emission performance of Cs_(4)CdBi_(2)Cl_(12) synthesized by hydrothermal *** functional theory calculations combined with experimental results evidence that the weak orange emission from Cs_(4)CdBi_(2)Cl_(12) is attributed to the phonon scattering and energy level crossing due to the large lattice distortion under excited ***,Ag^(+)ion doping breaks the intrinsic crystal field environment of Cs_(4)CdBi_(2)Cl_(12),suppresses the crossover between ground and excited states,and reduces the energy loss in the form of nonradiative *** a critical doping amount of 0.8%,the emission intensity of Cs_(4)CdBi_(2)Cl_(12):Ag^(+)reaches the maximum,about eight times that of the pristine ***,the doped Cs_(4)CdBi_(2)Cl_(12) still maintains excellent stability against heat,ultraviolet irradiation,and environmental oxygen/*** above advantages make it possible for this material to be used as solid-state phosphors for white LEDs applications,and the Commission International de I’Eclairage color coordinates of(0.31,0.34)and high color rendering index of 90.6 were *** importantly,the white LED demonstrates remarkable operation stability in air ambient,showing almost no emission decay after a long working time for 48 *** believe that this study puts forward an effective ion-doping strategy for emission enhancement of vacancy-ordered quadruple perovskite Cs_(4)CdBi_(2)Cl_(12),highlighting its great potential as efficient emitter compatible for practical applications.

关键词： Cs_(4)CdBi_(2)Cl_(12) self-trapped excitons ion doping emission enhancement stability

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Modelling of cantilever bank failure for peat-type meander bends in the source region of the Yellow River

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International Journal of Sediment Research 2023年第3期38卷 421-431页

作者： Hanyuan Yang Zhiwei Li Yongjun Lu Huaixiang Liu Liqin Zuo State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research Institute Yangtze Institute for Conservation and Development

Bank retreat involving a combination of fluvial erosion and bank collapse has been found to be a major contributor to sediment transport, lateral migration, and planform evolution of meandering *** studies have largely examined the general mechanism of cantilever bank failure. However, the composite process of beam(toppling) failure caused by shear failure of the lower part composed of noncohesive soil remains poorly understood. The current paper investigates the diversity and coupling of this collapse process, which is the dominant pattern in the peat-type meandering rivers of the Zoige River basin in the source region of the Yellow River. For this purpose, morphologic and hydraulic measurements were done in the summers of 2016 and 2017. Moreover, a combined method of a theoretical model and numerical simulation was developed to be applied for a continuous meandering channel in the Zoige basin, focusing in particular on five typical cross sections of a highly convoluted bend approaching neck cutoff. Specifically, the theoretical model evaluating the stability of overhanging riverbank was based on static equilibrium theory considering the interaction between composite soil layers. In addition, the Bank Stability and Toe Erosion Model was used to simulate the retreat process of the silt layer based on field measurements including bank morphology, soil composition, and hydrological parameters. Thus, a calculation method for the occurrence of cantilever beam failure in the flood period is proposed, and temporal change and spatial variability in bank profiles caused by three consecutive failures is estimated at the five sections. Satisfactory results showed a relatively close agreement between the calculations and field measurements in terms of the width of the overhanging arms and the dimensions of the slump blocks.

关键词： River bends Bank erosion Cantilever failure Numerical simulation Meandering river

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Current-perpendicular-to-plane transport properties of 2D ferromagnetic material CrTe_(2)

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Chinese Physics B 2024年第9期33卷 535-539页

作者： Jin Wang Yu Liu Taikun Wang Yongkang Xu ShuanghaiWang Kun He Yafeng Deng Pengfei Yan Liang He School of Electronic Science and Engineering Nanjing UniversityNanjing 210023China State Key Laboratory of Spintronics Nanjing UniversitySuzhou 215163China

Heterostructures of van der Waals(vdW)ferromagnetic materials have become a focal point in research of lowdimensional spintronic *** current direction in spin valves is commonly perpendicular to the plane(CPP).However,the transport properties of the CPP mode remain largely *** this work,current-in-plane(CIP)mode and CPP mode for CrTe_(2) thin films are carefully *** temperature-dependent longitudinal resistance transitions from metallic(CIP)to semiconductor behavior(CPP),with the electrical resistivity of CPP increased by five orders of *** importantly,the transport properties of the CPP can be categorized into a single-gap tunneling-through model with the activation energy(Ea)of1.34 meV/gap at 300–150 K,the variable range hopping model with a linear negative magnetoresistance at 150–20 K,and weak localization region with a nonlinear magnetic resistance below 20 *** study explores the vertical transport in CrTe_(2) materials for the first time,contributing to understand its unique properties and to pave the way for its potential in spin valve devices.

关键词： 2D vdW CrTe_(2) current-perpendicular-to-plane negative magnetic resistance

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Residence time distribution and heat/mass transfer performance of a millimeter scale butterfly-shaped reactor

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Chinese Chemical Letters 2023年第4期34卷 332-337页

作者： Haicheng Lv Jundi Wang Zhongming Shu Gang Qian Xuezhi Duan Zhirong Yang Xinggui Zhou Jing Zhang State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

A millimeter scale butterfly-shaped reactor was proposed based on sizing-up strategy and fabricated via femtosecond laser engraving. An improvement of mixing performance and residence time distribution was realized by means of contraction and expansion of the reaction channel. The liquid holdup was greatly increased through connection of multiple mixing units. Structure optimization of the reactor was carried out by computational fluid dynamics simulation, from which the effect of reactor internals on mixing and the influence of parallel branching structure on heat transfer were discussed. The UV–vis absorption spectroscopy was used to determine the residence time distribution in the reactor, and characteristic parameters such as skewness and dimensionless variance were obtained. Further, a chained stagnant flow model was proposed to precisely describe the trailing phenomenon caused by fluid stagnation and laminar flow in small scale reactors, which enables a better fit for the experimental results of the asymmetric residence time distribution. In addition, the heat transfer performance of the reactor was investigated, and the overall heat transfer coefficient was 110–600 W m^(-2)K-1in the flow rate range of 10–40 m L/min.

关键词： Millimeter scale reactor Computational fluid dynamics Residence time distribution Chained stagnant flow model Overall heat transfer coefficient

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Topologically close-packed intermetallic alloy electrocatalysts for CO_(2) reduction towards high value-added multi-carbon chemicals

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Chinese Chemical Letters 2025年第1期36卷 6-7页

作者： Qiyan Wu Qing Li State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The continuous combustion of unsustainable carbon-based fossil fuels has dramatically accelerated the increase in carbon dioxide(CO_(2))concentration in the atmosphere(from approximately278.3 ppm in 1750 to 417.9 ppm in 2023),which would exacerbate environmental problems such as greenhouse effect[1].The effective electrosynthesis of high value-added multi-carbon(C_(2+))chemicals(e.g.,ethanol,ethylene)from CO_(2) reduction reaction(CO_(2)RR)is a promising strategy to mitigate these environmental issues mentioned above but remains highly challenging due to the competition of hydrogen evolution reaction(HER)and low selectivity of target products.

关键词： intermetallic alloy carbon

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Open-loop Phase Synchronization Method of Positive and Negative Sequences for Three-phase Asymmetric Grid

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CSEE Journal of Power and Energy Systems 2023年第5期9卷 1973-1979页

作者： Jian He Shanxu Duan State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Currently,a grid-connected inverter is required to inject a dual-sequence current during asymmetric grid sags,which means both positive and negative sequence phases should be *** paper proposes an open-loop phase synchronization(OLS)method of positive and negative sequences for an asymmetric grid based on the moving average filter(MAF),which does not need to separate the positive and negative sequence fundamental components of grid *** a benefit,there is no double-frequency oscillation in the estimated phases at offnominal frequencies since the positive and negative sequence phases are obtained *** proposed method not only has the inherent advantages of OLS,but also further improves the dynamic response since the window length of MAF is only 1/6 of the fundamental *** effectiveness of the proposed OLS is verified by experimental results.

关键词： Asymmetric grid open-loop synchronization positive and negative sequence phases

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PPSKSQ: Towards Efficient and Privacy-Preserving Spatial keyword Similarity Query in Cloud

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IEEE Transactions on Cloud computing 2025年第2期13卷 544-559页

作者： Wang, Changrui Wu, Lei Xu, Lijuan Yuan, Haojie Wang, Hao Zhang, Wenying Meng, Weizhi Shandong Normal University School of Information Science and Engineering Jinan250358 China Key Laboratory of Computing Power Network and Information Security Ministry of Education China Lancaster University School of Computing and Communications United Kingdom

The growth of cloud computing has led to the widespread use of location-based services, such as spatial keyword queries, which return spatial data points within a given range that have the highest similarity in keyword sets to the user's. As the volume of spatial data increases, providers commonly outsource data to powerful cloud servers. Because cloud servers are untrustworthy, privacy-preserving keyword query schemes have been proposed. However, existing schemes consider only location queries or exact keyword matching. To address these issues, we propose the Privacy-Preserving Spatial keyword Similarity Query Scheme (PPSKSQ), designed to search for spatial data points with the highest similarity while protecting the privacy of outsourced data, query requests, and results. First, we design two sub-protocols based on improved symmetric homomorphic encryption (iSHE): iSHE-SC for secure size comparison and iSHE-SIP for secure inner product computation. Then, we encode range information and integrate it with a quadtree to construct a novel index structure. Additionally, we use the Jaccard to measure similarity in conjunction with the iSHE-SC protocol, transforming similarity comparison into a matrix trace operation. Finally, rigorous security analysis and extensive simulation experiments confirm the flexibility, efficiency, and scalability of our scheme. © 2013 IEEE.

关键词： Structured Query Language

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Tough Hydrogen Bonding Crosslinked Poly(3-fluorothiophene)Network via Electrosynthesis for High-performance Electrochromic Supercapacitors

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Chinese Journal of Polymer science 2024年第11期42卷 1749-1757,I0011页

作者： Chun-Hui Du Yu-Hua Xu Hui Li Zhi-Xin Wu Han-Jun Yang Xi-Mei Liu Bao-Yang Lu Guang-Ming Nie Ge Zhang Jiangxi Key Lab of Flexible Electronics Flexible Electronics Innovation InstituteJiangxi Science&Technology Normal UniversityNanchang330013China Key Laboratory of Optic-Electric Sensing and Analytical Chemistry for Life Science MOEState Key Laboratory Base of Eco-chemical EngineeringCollege of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao266042China

As a type of bi-functional device,electrochromic supercapacitors(EC-SCs)have attracted extensive attention in diverse applications such as flexible ***,despite recent encouraging progress,rational design and development of high-performance EC-SC materials with desirable stability remain challenging for practical ***,we propose a fluorination strategy to develop high-performance EC-SC materials with tough hydrogen bonding cross-linked intermolecular polymer network by one-step electrosynthesis of *** electrosynthesized free-standing poly(3-fluorothiophene)(PFT)films simultaneously achieve high electrochromic performance(optical contrast 42%at 560 nm with reversible color changes between purple and blue),and good capacitance property(290 F·g^(-1),1 A·g^(-1)),as well as outstanding cyclic stability(<2%reduction after 20000 cycles).We further demonstrate the fabrication of PFT-based flexible electrochromic supercapacitor devices(FESDs),and the resultant devices can be used to visually monitor the energy storage state in real-time and maintain outstanding stability under mechanical distortion like *** a tough fluorination hydrogen bonding cross-linking strategy may provide a new design concept for high-performance EC-SC materials and reliable FESDs toward practical applications.

关键词： Flexible electrochromic-supercapacitors Conducting polymers Hydrogen bonding crosslinking Electrosynthesis Polythiophene

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Knittable and washable aerogel fiber inspired by polar bear hair

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science China Materials 2024年第2期67卷 705-706页

作者： Yue Liu Huisheng Peng State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Scienceand Institute of Fiber Materials and DevicesFudan UniversityShanghai 200438China

The advances in chemistry and materials have boosted the development of smart textiles,which are poised to revolutionize human lifestyles through multifunctional integration,such as heating,cooling,sensing and supplying energy^([1,2]).Among them,thermal insulation is an essential function of textiles to protect humans from complex and extreme environments and realize personal thermal management without energy con-sumption^([3]).

关键词： textiles insulation extreme

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Research advances on electrode materials for solid oxide electrolysis cells

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Progress in Natural science:Materials International 2023年第3期33卷 309-319页

作者： Hongyuan Su Duoli Wu Chengxin Li Changjiu Li Chao Zhang College of Mechanical Engineering Yangzhou University State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and Engineering Xi'an Jiaotong University

Solid oxide electrolytic cell(SOEC) is an energy conversion device that transfers electrical energy into chemical energy. It has garnered significant attention due to its high efficiency and thick current density. The oxygen evolution reaction(OER) and the hydrogen evolution reaction(HER) are two crucial half-reactions of SOEC, while both require excellent electrochemical performance under high-temperature and high-humidity ***, high catalytic activity and good stability of electrode materials are crucial for the practical application of SOEC. The perovskite structure of the oxygen electrodes has outstanding OER activity, while metal ceramic and metal oxide hydrogen electrodes possess good redox properties. This article firstly demonstrates the influence of the physical and electrochemical properties of electrode materials on the performance of SOEC, then illustrates the optimization strategies for electrode materials to improve electrolysis efficiency and extend service ***, the research priorities for the future development of electrode material are summarized.

关键词： Solid oxide electrolysis cell Oxygen electrode Hydrogen electrode Perovskite oxide

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