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Pr-Tb synergistic strengthening on coercivity of Nd-Ce-Fe-B magnets grain boundary diffused with Pr-Tb-Al-Ga alloys

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Journal of Rare Earths 2024年第9期42卷 1704-1709,I0003页

作者： Ruifang Song Hang Zhao Haibo Feng institute of functional materials Central Iron&Steel Research InstituteBeijing100081China

Sintered Nd-Ce-Fe-B magnets were grain boundary diffused(GBDed) with Pr_(x)Tb_(80-x)Al_(10)Ga_(10)(at%)(x=0,20,40,60,80) *** effect of Pr/Tb content in diffusion source on magnetic properties,microstructure and elements distribution of GBDed magnets was *** Pr is used to substitute for 75% Tb in diffusion source,Tb consumption per unit coercivity improvement of GBDed magnet reduces by 77%,compared with the Tb_(80)Al_(10)Ga_(10) diffused *** element diffuses into magnets and then forms Tb-rich shell with high magneto-crystalline anisotropy field surrounding main phase grains,resulting in substantial coercivity *** with low melting point diffuses deeply along liquid grain boundary phase during GBD *** can eliminate some sharp defects of main phase grains and make grain boundaries smooth,which provides diffusion channels for further diffusion of Tb ***,there are more diffusion channels for Tb and less Tb enriched at surface region,making Tb diffuse more deeply and improving Tb utilization *** method significantly improves the coercivity,and realizes the green,efficient and high-quality utilization of heavy rare earth(HRE)elements.

关键词： Grain boundary diffusion Rare earths Microstructure Synergistic strengthening

Electroluminescence from pure resonant states in hBN-based vertical tunneling junctions

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Light(Science & Applications) 2024年第8期13卷 1557-1564页

作者： Magdalena Grzeszczyk Kristina Vaklinova Kenji Watanabe Takashi Taniguchi Konstantin SNovoselov Maciej Koperski institute for functional Intelligent materials National University of SingaporeSingapore 117544Singapore Research Center for functional materials National Institute for Materials ScienceTsukuba 305-0044Japan International Center for materials Nanoarchitectonics National Institute for Materials ScienceTsukuba 305-0044Japan Department of materials Science and Engineering National University of SingaporeSingapore 117575Singapore

Defect centers in wide-band-gap crystals have garnered interest for their potential in applications among optoelectronic and sensor ***,defects embedded in highly insulating crystals,like diamond,silicon carbide,or aluminum oxide,have been notoriously difficult to excite electrically due to their large internal *** address this challenge,we realized a new paradigm of exciting defects in vertical tunneling junctions based on carbon centers in hexagonal boron nitride(hBN).The rational design of the devices via van der Waals technology enabled us to raise and control optical processes related to defect-to-band and intradefect *** fundamental understanding of the tunneling events was based on the transfer of the electronic wave function amplitude between resonant defect states in hBN to the metallic state in graphene,which leads to dramatic changes in the characteristics of electrons due to different band structures of constituent *** our devices,the decay of electrons via tunneling pathways competed with radiative recombination,resulting in an unprecedented degree of tuneability of carrier dynamics due to the significant sensitivity of the characteristic tunneling times on the thickness and structure of the *** enabled us to achieve a high-efficiency electrical excitation of intradefect transitions,exceeding by several orders of magnitude the efficiency of optical excitation in the sub-band-gap *** work represents a significant advancement towards a universal and scalable platform for electrically driven devices utilizing defect centers in wide-band-gap crystals with properties modulated via activation of different tunneling mechanisms at a level of device engineering.

关键词： carbide tunneling defect

Sulfonated carbon dots modified IrO_(2)nanosheet as durable and high-efficient electrocatalyst for boosting acidic oxygen evolution reaction

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Nano Research 2024年第9期17卷 8017-8024页

作者： Mengjie Ma Wenxiang Zhu Fan Liao Kui Yin Hui Huang Kun Feng Dongdong Gao Jinxin Chen Zenan Li Jun Zhong Lai Xu Yang Liu Mingwang Shao Zhenhui Kang institute of functional Nano and Soft materials(FUNSOM) Jiangsu Key Laboratory for Carbon-based Functional Materials and DevicesSoochow UniversitySuzhou 215123China Macao institute of materials Science and Engineering(MIMSE) Macao University of Science and TechnologyTaipaMacao 999078China

Oxygen evolution reaction(OER)plays a crucial role in developing energy conversion and adjusting electronic structure of the electrocatalysts can effectively improve the catalytic activity and ***,it is a challenge to adjust the electronic structure on two-dimensional iridium dioxide nanosheets(IrO_(2)NS),which have the advantages of high atom ***,we regulate the surface properties of IrO_(2)NS through sulfonated carbon dots(SCDs)to promote the OER catalytic *** catalyst IrO_(2)NS/SCDs-2 exhibited excellent catalytic activity with a lower overpotential of 180 mV than IrO_(2)NS(230 mV)at the current density of 10 mA·cm^(-2)in a 0.5 M H_(2)SO_(4) *** after 160 h of stability testing,the overpotential of IrO_(2)NS/SCDs-2 only decreased by 4 ***,transient potential scanning test can visually demonstrate that the addition of SCDs improves the conductivity of the catalyst and increases the electron transfer rate.

关键词： sulfonated carbon dots oxygen evolution reaction electrocatalysis transient potential scanning

Thermal stability improvement and microstructure optimization of high cobalt content Nd-Fe-B magnets via terbium grain boundary diffusion

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Journal of Rare Earths 2024年第8期42卷 1531-1538,I0004页

作者： Jiyuan Xu Ruiyang Meng Jing Liu Jiateng Zhang Rui Han Yikun Fang Shengzhi Dong Wei Li Division of functional materials Research Central Iron and Steel Research InstituteBeijing100081China

The substitution of Fe by Co in the 2:14:1 phase is an effective method to increase the Curie temperature and enhance the thermal stability of the Nd-Fe-B ***,the accumulation of Co ele ment at the grain boundaries(GBs) changes the GBs from nonmagnetic to ferromagnetic and causes the thinlayer GBs to become rare,In this paper,the method of diffusing Tb element was chosen to improve the microstructure and temperature stability of high-Co *** original sintered Nd_(28.5)Dy_(3)-CO_(x)e_(bal)M_(0.6)B_(i)(x=0,6 wt%,12 wt%;M = Cu,Al,Zr) magnets with different Co contents were diffused with Tb by grain boundary diffusion(GBD).After GBD,high-Co magnets exhibit more continuously distributed thin-layer GBs,and their thermal stability is significantly *** high-Co magnets(x=6 wt%),the absolute value of the temperature coefficient of coercivity decreases from 0.603%/K to0.508%/K in the temperature range of 293-413 K,that of remanence decreases from 0.099%/K to 0.091%/K,and the coercivity increases from 18.44 to 25.04 *** electron microscopy(TEM)characterization reveals that there are both the 1:2 phase and the amorphous phase in the high-Co magnet before and after GBD,EDS elemental analysis shows that Tb element is more likely to preferentially replace the rare earth elements in the 2:14:1 main phase than in the 1:2 phase and the amorphous *** concentration of Tb at the edge of the main phase is much higher than that in the 1:2phase and amorphous phase,which is beneficial to the improvement of the *** preferential replacement of Tb elements at the edge of the 2:14:1 phase and thin-layer GBs with a more continuous distribution are synergistically responsible for improving the thermal stability of high-Co *** study indicates that GBD is an effective method to improve the microstructure and thermal stability of high-Co magnets.

关键词： Nd-Fe-B magnets Coercivity Grain boundary diffusion Thermal stability Micro structure Rare earths

Narrowband blue emitter based on fused nitrogen/carbonyl combination with external quantum efficiency approaching 30%

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Science China Chemistry 2024年第1期67卷 351-359页

作者： Long Chen Jia-Heng Cai You-Jun Yu Yang-Kun Qu Sheng-Yi Yang Sheng-Nan Zou Rui-Hong Liu Dong-Ying Zhou Liang-Sheng Liao Zuo-Quan Jiang institute of functional Nano&Soft materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials&DevicesSoochow UniversitySuzhou 215123China Macao institute of materials Science and Engineering Macao University of Science and TechnologyMacao 999078China

Multi-resonance thermally activated delayed fluorescence(MR-TADF)emitters can enable narrowband emission with high color purity and electroluminescence ***/carbonyl(N/C=O)system is receiving increasing attention while the nitrogen/boron(N/B)system has been widely *** decoration is an effective approach for N/B type MR-TADF system but always leads to broadening and red-shifting of the emission band in N/C=O MR-TADF *** attribute these unfavorable phenomena to the formation of intramolecular charge transfer between the MR-core and peripheral *** address this issue,we have developed a new strategy by decorating DMQAO(a fused N/C=O MR-core)with a triazine acceptor and a neutral terphenyl group to construct MTDMQAO and MBDMQAO,*** introduction of the triazine acceptor not only realizes efficient narrowband emission in MTDMQAO,but also accelerates the reverse intersystem crossing process through enhanced spin-orbital *** a result,MTDMQAO exhibits a significantly higher external quantum efficiency of 29.4%compared to the referent emitters,validating the rationality of our derivation *** study highlights the potential of the N/C=O system for MR-TADF emitters and provides important insights for understanding the difference between N/B and N/C=O systems.

关键词： carbonyl group narrowband acceptor decoration thermally activated delayed fluorescence OLEDs

Reduced Macrophage Uptake of Nanoparticles through Surface Modification of Polypeptides with Valine Residues

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Chinese Journal of Chemistry 2024年第11期42卷 1209-1216页

作者： Ning Li Shanshan Xiao Xiaoxiong Jin Ziyuan Song institute of functional Nano&Soft materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and DevicesSoochow UniversitySuzhouJiangsu215123 China

The structural and surface properties of nanomedicines play an important role in determining their biological fate. Surface chemistry of nanomedicines is one of the key parameters, where researchers used various strategies such as PEGylation to avoid the undesired clearance of nanoparticles (NPs) for enhanced targeting effect. Nevertheless, the fine-tuning of surface chemistry through polymer functionalization remains largely unexplored. In this concise report, we find that the incorporation of only 10 mol% valine residues into the surface-anchored poly(L-glutamic acid) significantly lowered the macrophage uptake of NPs. The introduction of other hydrophobic amino acid residues, however, increased the NPs internalization instead. The chirality and the side-chain structure of valine played an important role in the unexpected uptake behavior. We believe this work highlights the impact of slight changes of the surface-anchored polymer structure on the behavior of NPs, drawing people's attention to the careful design of surface chemistry to optimize the nanomedicine design.

关键词： Nanoparticles Copolymers Structure-activity relationships Surface chemistry Polypeptide Macrophage uptake

Temperature-adaptive metasurface radiative cooling device with excellent emittance and low solar absorptance for dynamic thermal regulation

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Advanced Photonics 2024年第4期6卷 70-82页

作者： Junlin Yang Qianyi Li Shiqiao Liu Debao Fang Jingyao Zhang Haibo Jin Jingbo Li Beijing institute of Technology School of Materials Science and EngineeringBeijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green ApplicationsBeijingChina

Passive radiative cooling is a promising passive cooling technology that emits heat to deep space without energy ***,the persistent challenge of overcooling in static radiative techniques has raised *** a desirable solution is suggested based on vanadium dioxide(VO_(2))in the form of a Fabry-Perot(F-P)resonant cavity,the inherent contradiction between desired high emissivity(ε)and low solar absorptance(α_(sol))remains a notable ***,we employed a simple mask-filling technique to develop a temperature-adaptive metasurface radiative cooling device(ATMRD)for dynamic thermal *** and experimental results substantially evidenced that multiple localized polariton resonances were induced by the VO_(2)metasurface,significantly enhancing the thermal emittance of the *** engineered ATMRD achieved an amazing switch of the atmospheric window emittance from 0.13 to 0.85 when the surface temperature exceeds a pre-set transition temperature,accompanied by a commendableα_(sol)of 27.71%.The mechanism of multiple localized polariton resonances is discussed in detail to understand the enhanced performance based on the investigation of the relationship between the metasurface structure and multiple localized polariton *** demonstrate an efficient smart radiative technique achieved by a simple micro/nanoprocess and,most importantly,contribute a valuable reference for the design of radiative devices,which is crucial in various areas such as passive cooling,smart windows,multifunctional electromagnetic response,and space application technologies.

关键词： dynamic radiative cooling metasurface vanadium dioxide emittance plasmon resonance

Near-infrared organic lasers with ultra-broad emission bands by simultaneously harnessing four-level and six-level systems

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Chinese Chemical Letters 2024年第8期35卷 288-293页

作者： Lei Wang Jun-Jie Wu Chang-Cun Yan Wan-Ying Yang Zong-Lu Che Xin-Yu Xia Xue-Dong Wang Liang-Sheng Liao Jiangsu Key Laboratory for Carbon-Based functional materials&Devices Institute of Functional Nano&Soft Materials(FUNSOM)Soochow UniversitySuzhou 215123China Jiangsu Engineering Laboratory of Novel functional Polymeric materials College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Macao institute of materials Science and Engineering Macao University of Science and TechnologyMacao SAR 999078China

Organic lasers with broad emission bands in near-infrared(NIR)region are crucial for their applications in laser communication,night-vision as well as bioimaging owing to the abundance of selectable lasing ***,for most organic gain materials,gain regions are limited in a small wavelength range because of the fixed energy level ***,we design a strategy to realize NIR organic lasers with broad emission bands based on tunable energy level systems induced by cascaded excited-state intramolecular proton transfer(ESIPT).A novel gain material named DHNN was developed,which can undergo a cascaded double-ESIPT process supporting four-level and six-level systems *** doping DHNN into polystyrene microspheres,NIR lasers with tunable emission bands can be achieved based on the careful modulation of ***,organic lasers with an ultra-broad emission band ranging from 700 nm to 900 nm was successfully achieved by harnessing four-level and six-level systems simultaneously.

关键词： Excited-state intramolecular proton transfer Organic solid-state laser Wide gain interval Near-infrared emission Molecular design

Emerging high-entropy strategy: A booster to the development of cathode materials for power batteries

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Journal of Advanced Ceramics 2024年第8期13卷 1093-1118页

作者： Liping Huang Jinging Zhu J-Xuan Liu Houzheng Wu Guo-Jun Zhang State Key Laboratory for Modification of Chemical Fibers and Polymer materials Institute of Functional MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai 201620China SIAMC Advanced materials Cooperation Huzhou 313100China

The coordinated development of new energy vehicles and the energy storage industry has become essential for reducing carbon *** cathode material is the key material that determines the energy density and cost of a power battery,but currently developed and applied cathode materials cannot meet the requirements for high specific capacity,low cost,safety,and good ***-entropy materials(HEMs)are a new type of single-phase material composed of multiple principal elements in equimolar or near-equimolar *** interaction between multiple elements can play an important role in improving the comprehensive properties of the material,which is expected to solve the limitations of battery materials in practical ***,this review provides a comprehensive overview of the current development status and modification strategies of power batteries(lithium-ion batteries(LiBs)and sodium-ion batteries(SIBs)),proposes a high-entropy design strategy,and analyses the structure-activity relationship between the high-entropy effects and battery ***,future research topics related to high-entropy cathode materials,including computational guide design,specific synthesis methods,high-entropy electrochemistry,and high-throughput databases,are *** review aims to provide practical guidance for the development of high-entropy cathode materials for next-generation power batteries.

关键词： cathode materials lithium-ion battery(LIB) sodium-ion battery(SIB) high-entropy strategy