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Effect of grain boundary diffusion of terbium on mode of mechanical fracture of sintered NdFeB magnets

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Journal of Rare Earths 2024年第4期42卷 696-704页

作者： zexin Lu Tinghui Wang Jianjun Jiang Bizhang zheng Lijing yang Xingqi He Anli Lin Shengzhi dong zhenlun Song CAS Key Laboratory of Magnetic Materials and Devices Zhejiang Province Key Laboratory of Magnetic Materials and Application TechnologyNingbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo315201China Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo315211China Ningbo Xinqi Precision Magnetism Steel Co. Ltd..Ningbo315156China Center for Advanced Measurement Science National Institute of MetrologyBeijing102200China Division of Functional Materials Central Iron&Steel Research InstituteBeijing100081China

Grain boundary diffusion process(GBDP)is a widely used method of increasing the coercivity of sintered NdFeB *** this study,the effects of the GBDP on the bending strength and microhardness of sintered NdFeB magnets and the fracture mode were *** show that the bending strength of magnets is reduced by pickling and heat treatment and greatly recove rs after heavy rare earth element(Tb)grain boundary *** pickling and the heat treatment cause a slight decrease in *** with the recovery of the bending strength,the hardness decreases after the *** fracture mode of bended magnets changes from intergranular to *** study helps in further improving the mechanical and magnetic properties of sintered NdFeB magnets.

关键词： Sintered NdFeB magnets Grain boundary diffusionprocess Bending strength Heavy rare earth element Coercivity

Deep Insight of Design,Mechanism,and Cancer Theranostic Strategy of Nanozymes

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Nano-Micro Letters 2024年第2期16卷 165-217页

作者： Lu yang Shuming dong Shili Gai Dan yang He Ding Lili Feng Guixin yang ziaur Rehman Piaoping yang Key Laboratory of Superlight Materials and Surface Technology Ministry of EducationCollege of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001People’s Republic of China yantai Research Institute Harbin Engineering UniversityYantai 264000People’s Republic of China Key Laboratory of Green Chemical Engineering and Technology of Heilongjiang Province College of Material Science and Chemical EngineeringHarbin University of Science and TechnologyHarbin 150040People’s Republic of China Department of Chemistry Quaid-i-Azam UniversityIslamabad 45320Pakistan

Since the discovery of enzyme-like activity of Fe3O4 nanoparticles in 2007,nanozymes are becoming the promising substitutes for natural enzymes due to their advantages of high catalytic activity,low cost,mild reaction conditions,good stability,and suitable for large-scale ***,with the cross fusion of nanomedicine and nanocatalysis,nanozyme-based theranostic strategies attract great attention,since the enzymatic reactions can be triggered in the tumor microenvironment to achieve good curative effect with substrate specificity and low side ***,various nanozymes have been developed and used for tumor *** this review,more than 270 research articles are discussed systematically to present progress in the past five ***,the discovery and development of nanozymes are ***,classification and catalytic mechanism of nanozymes are ***,activity prediction and rational design of nanozymes are focused by highlighting the methods of density functional theory,machine learning,biomimetic and chemical ***,synergistic theranostic strategy of nanozymes are ***,current challenges and future prospects of nanozymes used for tumor theranostic are outlined,including selectivity,biosafety,repeatability and stability,in-depth catalytic mechanism,predicting and evaluating activities.

关键词： Nanozymes Classification Prediction and design Catalytic mechanism Tumor theranostics

Multifunctional MOF@COF Nanoparticles Mediated Perovskite Films Management Toward Sustainable Perovskite Solar Cells

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Nano-Micro Letters 2024年第9期16卷 195-208页

作者： yayu dong Jian zhang Hongyu zhang Wei Wang Boyuan Hu Debin Xia Kaifeng Lin Lin Geng yulin yang MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001HeilongjiangPeople’s Republic of China School of Materials Science and Engineering East China Jiaotong UniversityNanchang 330013JiangxiPeople’s Republic of China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001HeilongjiangPeople’s Republic of China

Although covalent organic frameworks(COFs)with highπ-conjugation have recently exhibited great prospects in perovskite solar cells(PSCs),their further application in PSCs is still hindered by face-to-face stacking and aggregation ***,metal-organic framework(MOF-808)is selected as an ideal platform for the in situ homogeneous growth of a COF to construct a core-shell MOF@COF nanoparticle,which could effectively inhibit COF stacking and *** synergistic intrinsic mechanisms induced by the MOF@COF nanoparticles for reinforcing intrinsic stability and mitigating lead leakage in PSCs have been *** complementary utilization ofπ-conjugated skeletons and nanopores could optimize the crystallization of large-grained perovskite films and eliminate *** resulting PSCs achieve an impressive power conversion efficiency of 23.61%with superior open circuit voltage(1.20 V)and maintained approximately 90%of the original power conversion efficiency after 2000 h(30-50%RH and 25-30℃).Benefiting from the synergistic effects of the in situ chemical fixation and adsorption abilities of the MOF@COF nanoparticles,the amount of lead leakage from unpackaged PSCs soaked in water(y assessment required for the Resource Conservation and Recovery Act Regulation.

关键词： Perovskite solar cells Covalent organic frameworks Metal-organic frameworks Lead leakage Stability

Electronic structure and spin state regulation of vanadium nitride via a sulfur doping strategy toward flexible zinc-air batteries

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Journal of Energy Chemistry 2024年第2期89卷 239-249,I0007页

作者： Daijie Deng Honghui zhang Jianchun Wu Xing Tang Min Ling Sihua dong Li Xu Henan Li Huaming Li Institute for Energy Research Institute of Quantum and Sustainable TechnologySchool of Chemistry and Chemical EngineeringSchool of Materials Science and EngineeringJiangsu Province and Education Ministry Co-Sponsored Synergistic Innovation Center of Modern Agricultural EquipmentJiangsu UniversityZhenjiang 212013JiangsuChina Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province Nanjing 210023JiangsuChina zhenjiang Kangyuan Electrical Appliance Co. Ltd.Zhenjiang 212013JiangsuChina College of Chemical and Biological Engineering Zhejiang UniversityHangzhou 310027ZhejiangChina yTO Group Corporation dongfanghong(Henan)Agricultural Service Technology Co. Ltd.Luoyang 471033HenanChina

Owing to the distinctive structural characteristics,vanadium nitride(VN)is highly regarded as a catalyst for oxygen reduction reaction(ORR)in zinc-air batteries(zABs).However,VN exhibits limited intrinsic ORR activity due to the weak adsorption ability to O-containing ***,the S-doped VN anchored on N,S-doped multi-dimensional carbon(S-VN/Co/NS-MC)was constructed using the solvothermal and in-situ doping *** sulfur atoms into VN species alters the electron spin state of vanadium in the S-VN/Co/NS-MC for regulating the adsorption energy of vanadium sites to oxygen *** introduced sulfur atoms polarize the V 3d_(z)^(2) electrons,shifting spin-down electrons closer to the Fermi level in the S-VN/Co/***,the introduction of sulfur atoms into VN species enhances the adsorption energy of vanadium sites for oxygen ****OOH dissociation transitions from being unspontaneous on the VN surface to a spontaneous state on the S-doped VN ***,the ORR barrier on the S-VN/Co/NS-MC surface is *** S-VN/Co/NS-MC demonstrates a higher half-wave potential and limiting current density compared to the VN/Co/*** S-VN/Co/NS-MC-based liquid zABs display a power density of 195.7 m W cm^(-2),a specific capacity of 815.7 m A h g^(-1),and a cycling stability exceeding 250 *** S-VN/Co/NS-MC-based flexible zABs are successfully employed to charge both a smart watch and a mobile *** approach holds promise for advancing the commercial utilization of VN-based catalysts in zABs.

关键词： S-doped VN Electronic structures Spin state regulation Oxygen reduction reaction zinc-air batteries

The Lambert-G Family:Properties,Inference,and Applications

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 513-536页

作者： Jamal N.Al Abbasi Ahmed z.Afify Badr Alnssyan Mustafa S.Shama Accounting Department Ashur UniversityBaghdad10011Iraq Department of Statistics Mathematics and InsuranceBenha UniversityBenha13511Egypt Department of Management Information Systems and Production Management College of Business and EconomicsQassim UniversityBuraydah51452Saudi Arabia Department of Basic Sciences Common First Year(CFY)King Saud UniversityRiyadh11362Saudi Arabia Department of Mathematics and Statistics Osim Higher Institute of Administrative ScienceOsim12961Egypt

This study proposes a new flexible family of distributions called the Lambert-G *** Lambert family is very flexible and exhibits desirable *** three-parameter special sub-models provide all significantmonotonic and non-monotonic failure rates.A special sub-model of the Lambert family called the Lambert-Lomax(LL)distribution is *** expressions for the LL statistical properties are *** of the LL distribution are addressed mathematically based on its hazard *** estimation of the LL parameters is discussed using six estimation *** performance of this estimation method is explored through simulation *** usefulness and flexibility of the LL distribution are demonstrated empirically using two real-life data *** LL model better fits the exponentiated Lomax,inverse power Lomax,Lomax-Rayleigh,power Lomax,and Lomax distributions.

关键词： Lambert function Lomax distribution maximum likelihood hazard function statistical model simulation

Community structure and species diversity dynamics of a subtropical evergreen broad-leaved forest in China:2005 to 2020

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Plant Diversity 2024年第1期46卷 70-77页

作者： Shi-Guang Wei Lin Li Kun-dong Bai zhi-Feng Wen Jing-Gang zhou Qin Lin Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection(Guangxi Normal University) Ministry of EducationGuilin 541004GuangxiChina School of Life&Environmental Sciences Guilin University of Electronic TechnologyGuilin 541004GuangxiChina Guangxi Key Laboratory of Landscape Resources Conservation and Sustainable Utilization in Lijiang River Basin Guilin 541004GuangxiChina Key Laboratory of Vegetation Restoration and Management of South China Botanical Garden of Degraded Ecosystems Chinese Academy of SciencesGuangzhou 510650GuangdongChina Center of Plant Ecology Core Botanical GardensChinese Academy of SciencesGuangzhou 510650GuangdongChina

Here,we characterize the temporal and spatial dynamics of forest community structure and species diversity in a subtropical evergreen broad-leaved forest in *** found that community structure in this forest changed over a 15-year ***,renewal and death of common species was large,with the renewal of individuals mainly concentrated within a few populations,especially those of Aidia canthioides and Cryptocarya *** numbers of individual deaths for common species were concentrated in the small and mid-diameter *** spatial distribution of community species diversity fluctuated in each monitoring period,showing a more dispersed diversity after the 15-year study period,and the coefficient of variation on quadrats *** 2010,the death and renewal of the community and the spatial variation of species diversity were different compared to other survey *** weather may have affected species regeneration and community stability in our subtropical monsoon evergreen broad-leaved *** findings suggest that strengthening the monitoring and management of the forest community will help better understand the long-and short-term causes of dynamic fluctuations of community structure and species diversity,and reveal the factors that drive changes in community structure.

关键词： Community structure Death and renewal dynamics Species diversity dynamics South subtropical forest

Rational molecular design of efficient yellow-red dendrimer TADF for solution-processed OLEDs: a combined effect of substitution position and strength of the donors

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Science China Chemistry 2024年第5期67卷 1613-1623页

作者： Changfeng Si Dianming Sun Tomas Matulaitis David B.Cordes Alexandra M.z.Slawin Eli zysman-Colman Organic Semiconductor Centre EaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsKY169STUK

The development of high-performance solution-processed red organic light-emitting diodes(OLEDs) remains a challenge,particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized four novel orange-red thermally activated delayed fluorescence(TADF) dendrimers that are solution-processable: 2GCz BP, 2DPACz BP, 2FBP2GCz and 2FBP2DPACz. We systematically investigated the effect of substitution position and strength of donors on the optoelectronic properties. The reverse intersystem crossing rate constant(kRISC) of the emitters having donors substituted at positions 11and 12 of the dibenzo[a,c]phenazine(BP) is more than 10-times faster than that of compounds substituted having donors substituted at positions 3 and 6. Compound 2DPACz BP, containing stronger donors than 2GCz BP, exhibits a red-shifted emission and smaller singlet-triplet energy splitting, ΔE_(ST), of 0.01 e V. The solution-processed OLED with 10 wt% 2DPACz BP doped in m CP emitted at 640 nm and showed a maximum external quantum efficiency(EQE_(max)) of 7.8%, which was effectively maintained out to a luminance of 1,000 cd m-2. Such a device's performance at relevant display luminance is among the highest for solution-processed red TADF OLEDs. The efficiency of the devices was improved significantly by using 4Cz IPN as an assistant dopant in a hyperfluorescence(HF) configuration, where the 2DPACz BP HF device shows an EQEmaxof 20.0% at λEL of 605 nm and remains high at 11.8% at a luminance of 1,000 cd m-2, which makes this device one of the highest efficiency orange-to-red HF SP-OLEDs to date.

关键词： thermally activated delayed fluorescence solution-processing red OLEDs dibenzo[a,c]phenazine dendrimers

Decorating crystalline yFe_(2-x)Al_(x) on the Mg_(60)La_(10)Ni_(20)Cu_(10) amorphous alloy as “hydrogen pump” to realize fast de/hydrogenation

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Journal of Materials Science & Technology 2024年第6期173卷 72-79页

作者： L.J.Huang H.Wang L.z.Ouyang M.zhu H.J.Lin School of Materials Science and Engineering Key Laboratory of Advanced Energy Storage Materials of Guangdong ProvinceSouth China University of TechnologyGuangzhou 510641China Institute of Advanced Wear&Corrosion Resistance and Functional Materials Jinan UniversityGuangzhou 510632China

Mg-based amorphous alloys are one of the potential hydrogen storage materials but suffer from sluggish dehydrogenation/hydrogenation(de/hydrogenation)*** this work,as a new strategy,a hydrogen pump is built on the surface of amorphous alloys to solve this *** milling crystalline yFe_(2-x)Al_(x) hydrogen storage alloy with Mg_(60)La_(10)Ni_(20)Cu_(10) amorphous alloy,fine crystalline particles were seeded on amorphous alloy powder to form a“strawberry”*** to the TEM observation,a metallurgical bonding boundary formed between the Mg-based amorphous matrix and the y-Fe-Al crystalline *** microstructure and de/hydrogenation kinetics investigation,the“hydrogen pump”effect of the seeded crystalline alloy was confirmed,which makes it much easier for the hydrogen to dissociate on and diffuse through the surface of the Mg-based amorphous *** such effect,the H absorption rate of Mg_(60)La_(10)Ni_(20)Cu_(10) amorphous alloy became almost eight times faster and it absorbs ~2.8 wt.% in 1 h at 130℃ under 4.5 MPa-H_(2).Further,fast hydrogenation can even achieve at 70℃ and the low-temperature dehydrogenation kinetics of the amorphous hydride can be also greatly *** present work proves that surface modification is of great importance for obtaining Mg-based amorphous alloy with ideal hydrogen storage performance.

关键词： Hydrogen storage Mg-based amorphous alloy Hydrogen pump Composite structure

Electromagnetic Performance Analysis of Variable Flux Memory Machines with Series-magnetic-circuit and Different Rotor Topologies

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 3-11页

作者： Qiang Wei z.Q.zhu yan Jia Jianghua Feng Shuying Guo yifeng Li Shouzhi Feng Department of Electronic and Electrical Engineering The University of SheffieldSheffield S13JDU.K. IEEE the CRRC zhuzhou Institute Company Ltd. Zhuzhou 412001China

In this paper,the electromagnetic performance of variable flux memory(VFM)machines with series-magnetic-circuit is investigated and compared for different rotor *** on a V-type VFM machine,five topologies with different interior permanent magnet(IPM)arrangements are evolved and optimized under same *** on two-dimensional(2-D)finite element(FE)method,their electromagnetic performance at magnetization and demagnetization states is *** reveals that the iron bridge and rotor lamination region between constant PM(CPM)and variable PM(VPM)play an important role in torque density and flux regulation(FR)***,the global efficiency can be improved in VFM machines by adjusting magnetization state(MS)under different operating conditions.

关键词： Memory machine Permanent magnet Rotor topologies Series magnetic circuit Variable flux