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Local Excitation of Kagome Spin Ice Magnetism Seen by Scanning Tunneling Microscopy

Physical Review Letters 2024年第4期133卷 046503-046503页

作者： Hanbin Deng Tianyu Yang Guowei Liu Lu Liu Lingxiao Zhao Wu Wang Tiantian Li Wei Song Titus Neupert Xiang-Rui Liu Jifeng Shao Y. Y. Zhao Nan Xu Hao Deng Li Huang Yue Zhao Liyuan Zhang Jia-Wei Mei Liusuo Wu Jiaqing He Qihang Liu Chang Liu Jia-Xin Yin Department of Physics Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong) Shenzhen China Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Shenzhen Institute for Quantum Science and Engineering Institute for Advanced Studies School of Physical Science and Technology Guangdong Provincial Key Laboratory of Computational Science and Material Design

The kagome spin ice can host frustrated magnetic excitations by flipping its local spin. Under an inelastic tunneling condition, the tip in a scanning tunneling microscope can flip the local spin, and we apply this technique to kagome metal HoAgGe with a long-range ordered spin ice ground state. Away from defects, we discover a pair of pronounced dips in the local tunneling spectrum at symmetrical bias voltages with negative intensity values, serving as a striking inelastic tunneling signal. This signal disappears above the spin ice formation temperature and has a dependence on the magnetic fields, demonstrating its intimate relation with the spin ice magnetism. We provide a two-level spin-flip model to explain the tunneling dips considering the spin ice magnetism under spin-orbit coupling. Our results uncover a local emergent excitation of spin ice magnetism in a kagome metal, suggesting that local electrical field induced spin flip climbs over a barrier caused by spin-orbital locking.

关键词： Electrical properties Magnetism Spin ice Scanning tunneling microscopy Scanning tunneling spectroscopy Two-level models

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A facile approach to fabricating graphene/waterborne epoxy coatings with dual functionalities of barrier and corrosion inhibitor

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Journal of Materials science & technology 2022年第17期112卷 263-276页

作者： Suyun Liu Xuewan Wang Qi Yin Xiongzhi Xiang Xian-Zhu Fu Xian-Zong Wang Jing-Li Luo Shenzhen Key Laboratory of Polymer Science and Technology Guangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072China

A facile and environmentally-friendly method is developed to prepare graphene/waterborne epoxy(WEP)composite *** graphene nanosheets are produced with electrochemical-exfoliation in the solution containing surfactants,cetyl trimethyl ammonium bromide(CTAB)and sodium dodecyl sulfate(SDS).The nanosheets containing solution thus formed are subjected to a quick dialysis and then directly used as a diluent for WEP without any further *** preparation method overcomes the commonly identified problems of aggregations and‘corrosion promotion’effect associated with graphene,and increases the impedance of the composite coatings by more than two orders of *** analysis of anticorrosion performance suggested that the presence of surfactants not only improves the dispersibility of graphene nanosheets but also endows the composite coatings with both barrier and corrosion inhibition *** strategy reported herein may pave the path to the large-scale production of graphene anticorrosion coatings.

关键词： Electrochemical-exfoliation graphene Waterborne epoxy coatings Anticorrosion Inhibition

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Over 16% efficiency all-polymer solar cells by sequential deposition

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science China Chemistry 2022年第6期65卷 1157-1163页

作者： Bangbang Li Xuanyu Zhang Ziang Wu Jie Yang Bin Liu Qiaogan Liao Junwei Wang Kui Feng Rui Chen Han Young Woo Fei Ye Li Niu Xugang Guo Huiliang Sun Department of Materials Science and Engineering Southern University of Science and Technology(SUSTech)Shenzhen518055China Center for Advanced Analytical Science School of Chemistry and Chemical EngineeringGuangzhou UniversityGuangzhou510006China Department of Electrical and Electronic Engineering Southern University of Science and Technology(SUSTech)Shenzhen518055China Department of Chemistry Korea UniversitySeoul136-713Republic of Korea Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices SUSTechShenzhen518055China

All-polymer solar cells(all-PSCs) have received extensive attention due to their excellent mechanical robustness and performance stability. However, the power conversion efficiency(PCE) of all-PSCs still lags behind those of organic solar cells(OSCs)based on non-fullerene small molecule acceptors. Herein, we report highly efficient all-PSCs via sequential deposition(SD) with donor and acceptor layers coated sequentially to optimize the film microstructure. Compared with the bulk heterojunction(BHJ)all-PSCs, an optimized morphology with vertical component distribution was achieved for the SD-processed all-PSCs due to the synergistic effect of swelling of polymer films and using additive. Such strategy involves using chlorobenzene as the first layer processing-solvent for polymer donor, chloroform as the second processing-solvent for polymer acceptor with trace 1-chloronaphthalene, efficiently promoting exciton dissociation and charge extraction and reducing trap-assisted ***, over 16% all-PSCs fabricated via SD method was realized for the first time, which is much higher than that(15.2%) of its BHJ counterpart and also among the highest PCEs in all-PSCs. We have further demonstrated the generality of this approach in various all-polymer systems. This work indicates that the SD method can yield excellent all-PSCs and provides a facile approach to fabricating high-performance all-PSCs.

关键词： all-polymer solar cells polymer acceptors planar heterojunction sequential deposition

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The Phase Transformation and Enhancing Mechanical Properties in High Zn/Mg Ratio Al-Zn-Mg-Cu(-Si) Alloys

SSRN

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SSRN 2024年

作者： Lu, Yi Wen, Shengping Gao, Kunyuan Xiong, Xiangyuan Wei, Wu Wu, Xiaolan Huang, Hui Nie, Zuoren College of Materials Science & Engineering Beijing University of Technology Beijing100124 China Key Laboratory of Advanced Functional Materials China

Aging behavior and strengthening mechanism of Al–5Zn–1Mg–1Cu(-Si) alloys under different isothermal temperature were investigated by means of mechanical tests and transmission electron microscope (TEM). The types of precipitated phases and mechanical properties were influenced by the aging temperature and the addition of Si. The addition of Si changed the precipitated phases from T' and η' phases to the dual-sized η and GPB-II phases. With increasing isothermal aging temperature, more GPB-II phases formed in alloys with the same composition, effectively improving the microhardness and mechanical properties. When aging at 150°C, 0.5wt% Si-containing alloy reached the highest peak hardness of about 150HV and maintained stable hardness, while an alloy without Si only reached 120HV and later declined by 15HV. The tensile strength and yield strength of the 0.5wt%Si-containing alloy were higher than those of non-Si alloy by 132 MPa and 165 MPa, increasing 51% and 90%, respectively. This result was due to the presence of fine and dispersed 4-8 nm GPB-II phases in 0.5wt%Si-containing alloy. The GPB-II phase had a core-shell structure, with the core region mainly enriched in Mg and Si, and the shell region mainly enriched in Cu and Zn. Compared with the stability of T' and η' phases, this core-shell structure of GPB-II effectively inhibited its growth and beneficially maintained a smaller sized GPB-II phase. The strengthening effect of GPB-II phase was better than that of η or T phases when aging at 150°C or 200°C. The mechanical properties of high Zn/Mg ratios Al-Zn-Mg-Cu alloys can enhanced by adding Si. © 2024, The Authors. All rights reserved.

关键词： Phase transitions

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Walnut septum-derived hierarchical porous carbon for ultra-high-performance supercapacitors

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Rare Metals 2022年第7期41卷 2280-2291页

作者： Meng Zhou Sheng-Xue Yan Qing Wang Ming-Xiu Tan Deng-Yang Wang Zi-Qi Yu Shao-Hua Luo Ya-Hui Zhang Xin Liu School of Materials Science and Engineering Northeastern UniversityShenyang 110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China School of Resources and Materials Northeastern University at QinhuangdaoQinhuangdao 066004China Hebei Key Laboratory of Dielectric and Electrolyte Functional Material Qinhuangdao 066004China Qinhuangdao Key Laboratory of Advanced Energy Storage and Conversion Technology Qinhuangdao 066004China

The conversion of biomass waste into eco-nomical and high-performance energy storage devices receives significant ***,a facile and green method to prepare porous active carbon from walnut sep-tum is applied to the electrode materials of *** effect of chemical etching reagent(KOH)on the microstructure and specific capacitance of the porous car-bon are *** modified BC-2.0,with a KOH/walnut septum mass ratio of 2∶1,exhibits large specific surface area of 1003.9 m^(2)·g^(-1)with hierarchical micro-mesoporous ***-2.0 reveals a superior specific capacitance of 457 F·g^(-1)at 1 A·g^(-1).The flexible sym-metric supercapacitor in gel electrolyte(KOH/PVA)exhi-bits considerable synergetic energy-power output *** results indicate that walnut septum is a better precursor to obtain activated carbons relative to other biomass carbon *** large mesoporosity after activation effectively boosts the electrochemical properties of ***,the walnut septum has potential to be a superior electrode material for supercapacitors.

关键词： Activation Biocarbon Micro-mesoporous structure Supercapacitor High specific capacitance

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Rational design of shortwave infrared(SWIR) fluorescence probe:Cooperation of ICT and ESIPT processes for sensing endogenous cysteine

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Chinese Chemical Letters 2022年第2期33卷 762-766页

作者： Maoju Chang Chenxu Yan Lei Shi Dan Li Wei Fu Zhiqian Guo Shanghai Key Laboratory of Functional Materials Chemistry Key Laboratory for Advanced Materials and Institute of Fine ChemicalsJoint International Research Laboratory of Precision Chemistry and Molecular EngineeringFeringa Nobel Prize Scientist Joint Research CenterFrontiers Science Center for Materiobiology and Dynamic ChemistrySchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Cysteine is well-known to be an important biothiol and related to many diseases. However, the in vivo detection of endogenous cysteine still suffers from lacking small-molecule fluorophores with both excitation and emission in the near-infrared(650-900 nm)/shortwave-infrared region. Herein, we report a molecular engineering strategy for shortwave infrared(SWIR, 900-1700 nm) sensing of cysteine, which integrated an excited-state intermolecular proton transfer(ESIPT) building block into the intramolecular charge transfer(ICT) scaffold. The obtained novel fluorophore SH-OH displays a maximum absorption at the NIR region, and emission at the SWIR region. We introduce the cysteine-recognition moiety to SH-OH structure, and demonstrate sensing of endogenous cysteine in living animals, using the SWIR emission as a reliable off-on fluorescence signal. This fluorophore design strategy of cooperation of ICT and ESIPT processes expands the in vivo sensing toolbox for accurate analysis in clinical applications.

关键词： Fluorescence probe Shortwave infrared Intramolecular charge transfer Excited-state intermolecular proton transfer Near-infrared

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High entropy(Yb0.25Y0.25Lu0.25Er0.25)2SiO5 with strong anisotropy in thermal expansion

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Journal of Materials science & technology 2020年第1期36卷 134-139页

作者： Heng Chen Huimin Xiang Fu-Zhi Dai Jiachen Liu Yanchun Zhou Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education School of Materials Science and EngineeringTianjin UniversityTianjin 300072China Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing 100076China

A novel high entropy(HE) rare earth monosilicate(Yb0.25Y0.25Lu0.25Er0.252 SiO5 was synthesized by solid-state reaction method.X-ray diffraction and scanning electron microscopy analysis indicate that a single solid solution is formed with homogeneous distribution of rare-earth ***(Yb0.25Y0.25Lu0.255 Er0.252 SiO5 exhibits excellent phase stability and anisotropy in thermal *** coefficients of thermal expansion(CTEs) in three crystallographic directions are:αa=(2.57±0.07)×10^-6 K^-1,αb=(8.07±0.13)×10^-6 K^-1,αc=(9.98±0.10)×10^-6 K^-*** strong anisotropy in thermal expansion is favorable in minimizing the coating/substrate mismatch if preferred orientation of HE(Yb0.25Y0.25Lu0.25Er0.252 SiO5 is controlled on either metal or ceramic substrate.

关键词： High entropy ceramics Rare earth monosilicates Solid-state reaction Thermal expansion Anisotropy

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Polyurethane-polysiloxane Copolymer Compatibilized SiR/TPU TPV with Comfortable Human Touch Toward Wearable Devices

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Chinese Journal of Polymer science 2023年第2期41卷 258-266页

作者： Hong-Fang Zhang Qian Hao Hong-Chi Tian Peng-Jun Yao Xue-Ying Liu Bing Yu Nan-Ying Ning Ming Tian Li-Qun Zhang Key Laboratory of Carbon Fiber and Functional Polymers Ministry of EducationBeijing University of Chemical TechnologyBeijing10029China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing100029China Shandong Dawn Polymer Material Co. Ltd.Longkou265700China Zhejiang Collaborative Innovation Center for High Value Utilization of Byproducts from Ethylene Project Ningbo PolytechnicNingbo315800China

Because of its softness,wear resistance,biocompatibility,extremely comfortable human touch,thermoplastic vulcanizate(TPV)comprised of silicone rubber(SiR)and thermoplastic polyurethane(TPU)(SiR/TPU TPV)is especially suitable for wearable intelligent ***,developing good compatibilizer is still required to prepare high performance SiR/TPU *** this study,three kinds of polyurethane-polysiloxane copolymer(PU-co-PSi)with different contents of polysiloxane segment were selected,and their compatibilization effect on SiR/TPU blends was studied using nanomechanical mapping technique of *** results show that using PU-co-PSi with the highest content of polysiloxane segment(PU-co-HPSi),the interface thickness largely increases,and the average size of SiR dispersed phase largely decreases,indicating its good compatibilization *** using PU-co-HPSi as compatibilizer,SiR/TPU TPV with a fine SiR dispersed phase and good mechanical performance were successfully *** mechanism on the compatibilization effect of these PU-co-PSi on SiR/TPU TPVs was revealed.

关键词： Silicone rubber(SiR) Thermoplastic polyurethane(TPU) Compatibilization Thermoplastic vulcanizate(TPV)

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Synaptic transistor with multiple biological functions based on metal-organic frameworks combined with the LIF model of a spiking neural network to recognize temporal information

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Microsystems & Nanoengineering 2023年第4期9卷 107-118页

作者： Qinan Wang Chun Zhao Yi Sun Rongxuan Xu Chenran Li Chengbo Wang Wen Liu Jiangmin Gu Yingli Shi Li Yang Xin Tu Hao Gao Zhen Wen School of Advanced Technology Xi’an Jiaotong-Liverpool UniversitySuzhou 215123P.R.China Department of Electrical Engineering and Electronics University of LiverpoolLiverpool L693GJUK School of Science Xi’an Jiaotong-Liverpool UniversitySuzhou 215123P.R.China Department of Electrical Engineering Eindhoven University of TechnologyDen Dolech 25612 AZ EindhovenThe Netherlands Institute of Functional Nano and Soft Materials(FUNSOM) Joint International Research Laboratory of Carbon-Based Functional Materials and DevicesSoochow UniversitySuzhou 215123P.R.China

Spiking neural networks(SNNs)have immense potential due to their utilization of synaptic plasticity and ability to take advantage of temporal correlation and low power *** leaky integration and firing(LIF)model and spike-timing-dependent plasticity(STDP)are the fundamental components of ***,a neural device is first demonstrated by zeolitic imidazolate frameworks(ZIFs)as an essential part of the synaptic transistor to simulate ***,three kinds of typical functions between neurons,the memory function achieved through the hippocampus,synaptic weight regulation and membrane potential triggered by ion migration,are effectively described through short-term memory/long-term memory(STM/LTM),long-term depression/long-term potentiation(LTD/LTP)and LIF,***,the update rule of iteration weight in the backpropagation based on the time interval between presynaptic and postsynaptic pulses is extracted and fitted from the *** addition,the postsynaptic currents of the channel directly connect to the very large scale integration(VLSI)implementation of the LIF mode that can convert high-frequency information into spare pulses based on the threshold of membrane *** leaky integrator block,firing/detector block and frequency adaptation block instantaneously release the accumulated voltage to form ***,we recode the steadystate visual evoked potentials(SSVEPs)belonging to the electroencephalogram(EEG)with filter characteristics of *** deeply fused by synaptic transistors are designed to recognize the 40 different frequencies of EEG and improve accuracy to 95.1%.This work represents an advanced contribution to brain-like chips and promotes the systematization and diversification of artificial intelligence.

关键词： transistor network neural

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A facile and green strategy to obtain organic room-temperature phosphorescence from natural lignin

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science China Chemistry 2022年第6期65卷 1100-1104页

作者： Ruihong Liu Tao Jiang Dongzhi Liu Xiang Ma School of Chemical Engineering and Technology Collaborative Innovation Center of Chemical Science and EngineeringTianjin Engineering Research Center of Functional Fine ChemicalsTianjin UniversityTianjin300354China Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center Frontiers Science Center for Materiobiology and Dynamic ChemistrySchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237China

Seeking pure organic functional luminescent materials that are processed from green, low-cost, and sustainable resources remains a challenging but beneficial task. As an abundant natural polymer composed of crosslinked phenol ether units, lignin is a potential source of organic luminescent material because of the presence of extensive aromatic fragments. In the present work, a remarkable afterglow involving room-temperature phosphorescence(RTP) was achieved via simply embedding alkalized lignin into polyvinyl alcohol(PVA) matrix, and an ultralong luminescence lifetime of more than 160 ms was observed. More importantly, our study revealed that small fragments of hydrolyzed lignin(named LA-H) bearing extensive phenolic oxygen anions were the effective luminescent species. When embedded into a PVA matrix, LA-H showed remarkably high luminescence quantum yield and long lifetime of RTP emission compared with those of unprocessed lignin. Additionally, the various phenol oxygen anion moieties endowed LA-H with an excitation-dependent characteristic: the color-tunable RTP could be simply tuned from a maximum emission wavelength of 434–532 nm via altering the excitation wavelength. Thus, the color-tunable afterglow of emissive LA-H could be facilely obtained with a yield up to 38.4% using simple acid hydrolysis of lignin without other complex synthesis procedures. This work opens new avenues in the large-scale preparation of low-cost and sustainable pure organic RTP materials.

关键词： room-temperature phosphorescence color-tunable lignin afterglow

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