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Journal of Forestry Research 2024年第5期35卷 26-36页

作者： andrés Baietto andrés Hirigoyen Jorge Hernández Amabelia del Pino Forest Department Faculty of AgronomyUniversity of the Republic12900 MontevideoUruguay National Research Program of Forest Production National Agriculture Research InstituteINIA97000 TacuarembóUruguay soil and Water Department Faculty of AgronomyUniversity of the Republic12900 MontevideoUruguay

Native grasslands in the Pampas of south America are increasingly being replaced by Eucalyptus and Pinus *** short rotation regimes used for the stands require high nutrient levels,with litterfall being a major source of nutrient *** model the litterfall production using climatic variables and assess the nutrient return in 14-year-old Eucalyptus grandis and Pinus taeda stands,we measured litter production over 2 years,using conical litter traps,and monitored climatic *** temperature,accumulated precipitation,and mean maximum vapor pres-sure deficit at the seasonal level influenced litterfall produc-tion by ***;seasonal accumulated precipitation and mean maximum temperature affected litterfall by *** regression tree modeling based on these climatic vari-ables had great accuracy and predictive power for ***(N=33;maE(mean absolute error)=0.65;RMsE(root mean square error)=0.91;R^(2)=0.71)and ***(N=108;maE=1.50;RMsE=1.59;R^(2)=0.72).The nutrient return followed a similar pattern to litterfall deposition,as well as the order of importance of macronutrients(***:Ca>N>K>Mg>P;***:N>Ca>K>Mg>P)and micronutrients(*** and ***:Mn>fe>Zn>Cu)in both *** study constitutes a first approximation of factors that affect litterfall and nutrient return in these systems.

关键词： Afforestation Litterfall Nutrient recycling Climate modeling Myrtaceae Pinaceae

Cross-linkedα-amylase aggregates on fe3O4 magnetic nanoparticles modified with polydopamine/polyethyleneimine for efficient hydrolysis of starch

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Particuology 2024年第7期90卷 98-105页

作者： Jiandong Cui Xiuming Tang Qingqing ma Yuyan Chang Qunli Zhang shiru Jia state Key Laboratory of Food Nutrition and safety Laboratory of Industrial Fermentation MicrobiologyMinistry of EducationTianjin University of Science and TechnologyTianjin 300457China Key Laboratory of Biomass Chemical Engineering of Ministry of Education Zhejiang UniversityHangzhou 310027China

In this workα-amylase was immobilized on magnetic fe3O4 nanoparticles with polyethylenimine(PEI)/polydopamine(PDA)coating or 3-aminopropyl triethoxysilane(APTEs)for the first time via adsorption–precipitation–*** with the freeα-amylase,the resultant magnetic cross-linkedα-amylase aggregates(PEI/PDA-M-CLEAs and N-M-CLEAs)exhibited excellent thermal and storage stability as well as pH *** storage at 25°C for 60 days,freeα-amylase only retained 60%of its initial activity,while PEI/PDA-M-CLEAs and N-M-CLEAs retained 80%and 78%of their initial activities,***,N-M-CLEAs and PEI/PDA-M-CLEAs showed good *** 6 repeated uses,PEI/PDA-M-CLEAs and N-M-CLEAs still maintained 65%and 62%of their initial activities,***,PEI/PDA-M-CLEAs and N-M-CLEAs exhibited higher starch hydrolysis efficiency than freeα-*** maximum dextrose equivalent(DE)values of starch hydrolysis by PEI/PDA-M-CLEAs and N-M-CLEAs reached 29.24%and 28.79%within 90 min,***,the maximum DE values of starch hydrolysis by the freeα-amylase was only 27.89%even in 150 *** magnetic cross-linkedα-amylase aggregates could be introduced as effective biocatalyst for industrial applications in production of maltose syrups.

关键词： α-amylase magnetic nanoparticles Functional modification magnetic cross-linked enzyme aggregates Hydrolysis of starch

Formation mechanism of fe-based amorphous powders produced by spark erosion

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Journal of materials science & Technology 2024年第3期170卷 33-46页

作者： Chekai Liu Ran Li Jiazi Bi Ding ma Xiaobin Liu Tao Zhang school of materials science and Engineering Key Laboratory of Aerospace Materials and Performance(Ministry of Education)Beihang UniversityBeijing 100191China

spark erosion is a convenient,flexible,and low-cost method to quickly produce fine powders of metals,alloys,and semiconductors in size ranging from nearly a hundred micrometers to submicrometer by repetitive spark *** to the complexity of the powder-forming journey,normally accompanied by high temperature,high pressure,decomposition,diffusion and rapid quenching caused by discharge plasma,the mechanisms of powder formation and possible contaminant infiltration are still controversial,posing a significant challenge to control particle size and chemical composition of the powder produced by this *** this study,fe-based amorphous powders in different particle-size distributions with high sphericity were fabricated by spark erosion under different discharge-energy *** max-imum particle size of the resultant powders can be correlated with discharge parameters,crater depth,and crater radius,respectively.A multi-ring-breakup model is proposed to reveal the particle-size distribution of the powder formed from the electrode melt under a single-pulse ***,a dielectric-element infiltration model is provided to quantitatively evaluate the infiltration mass ratio of the contaminant elements,stemming from the decomposed products of dielectric liquid,in the resultant powder with different particle *** models verified through the experimental data are significant for the development of high-performance fine fe-based amorphous powder with controlled particle size and chemical composition.

关键词： Amorphous alloy Particle spark erosion Infiltration Modeling

Achieving strength–ductility synergy in novel paramagnetic fe-based medium-entropy alloys through deep cryogenic deformation

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Rare Metals 2024年第9期43卷 4493-4507页

作者： Hu-Wen ma Yan-Chun Zhao Li feng Tian-Zeng Liu Zhi-Qi Yu Bo Jin Wang-Chun Duan Peter K.Liaw Dong ma state Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of Technology Wenzhou Pump and Valve Engineering Research Institute Lanzhou University of Technology Iron and steel Research Institute Jiuquan Iron and Steel Corporation Lanzhou Resources and Environment Voc-Tech University Department of materials science and Engineering The University of Tennessee Neutron science Center Songshan Lake Materials Laboratory

Cryogenic pre-deformation treatment has been widely used to effectively improve the comprehensive mechanical properties of steels and novel metals. However,the dislocation evolution and phase transformation induced by different degrees of deep cryogenic deformation are not yet fully elucidated. In this study, the effects of multiple cryogenic pre-treatments on the mechanical properties and deformation mechanisms of a paramagnetic fe63.3Mn14-si9.1Cr9.8C3.8medium-entropy alloy（MEA） were investigated, leading to the discovery of a pretreated MEA that exhibits exceptional mechanical properties, including a fracture strength of 3.0 GPa, plastic strain of 26.1% and work-hardening index of 0.57. In addition, X-ray diffraction（XRD） and transmission electron microscopy（TEM）analyses revealed that multiple cryogenic pre-deformation treatments significantly increased the dislocation density of the MEA(from 9 × 1015to 4 × 1016m-2after three pretreatments), along with a transition in the dislocation type from predominantly edge dislocations to mixed dislocations（including screw-and edge-type dislocations）. Notably, this pretreated MEA retained its paramagnetic properties（μrs showed that cryogenic pretreatment can significantly reduce the stacking fault energy of the MEA by a factor of approximately four(i.e., from 9.7 to2.6 m J·m-2), thereby activating the synergistic effects of transformation-induced plasticity, twinning-induced plasticity and dislocation strengthening mechanisms. These synergistic effects lead to simultaneous strength and ductility enhancement of the MEA.

关键词： Deep cryogenic transformation Dislocation evolution Iron-based medium-entropy alloys Phase transformation stacking fault energy

Effect of annealing temperature on magnetic properties of a sintered Nd-fe-B magnet after grain boundary diffusion with Dy_(70)Cu_(30) alloy

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Journal of Rare Earths 2024年第1期42卷 116-120,I0004页

作者： Ruipeng Qian Yuxuan ma Fugang Chen Hui sun Yong Zhao Yunlong Chen school of materials science and Engineering Jiangsu University of Science and TechnologyZhenjiang212003China school of Energy and Power Engineering Jiangsu University of Science and TechnologyZhenjiang212003China

Grain boundary diffusion process(GBDP)has been developed as an effective approach to increase the coercivity of sintered Nd-fe-B magnets by regulating the compositions and phase distributions near grain *** work aims to explore how to select the optimum annealing temperature after *** this work GBDP was performed on a sintered Nd-fe-B magnet using Dy_(70)Cu_(30) *** GBDP the low eutectic temperature of the grain boundary phases decreases from the initial 492 to 451℃.The magnetic property dependent on different annealing temperatures near the low eutectic temperature was *** magnetic properties,especially the squareness factor of demagnetization curve show a strong dependence on the annealing *** GBDP the optimal magnetic properties can be obtained after annealing just above the low eutectic temperature of the grain boundary *** mechanism is discussed based on the microstructure analysis.

关键词： Nd-fe-B magnet Grain boundary diffusion Annealing Dy_(70)Cu_(30)alloy Rare earths

fe-N_(x) sites coupled with core-shell fes@C nanoparticles to boost the oxygen catalysis for rechargeable Zn-air batteries

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Journal of Energy Chemistry 2024年第3期90卷 565-577,I0013页

作者： Katam srinivas Zhuo Chen Anran Chen fei ma Ming-qiang Zhu Yuanfu Chen school of Integrated Circuit science and Engineering and State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengdu 610054SichuanChina College of Mechanical and Electronic Engineering Northwest A&F UniversityYangling 712100ShaanxiChina school of materials and Energy Yunnan UniversityKunming 650091YunnanChina

The development of efficient single-atom catalysts(sACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To address such issue,herein,fe-N_(x) sites coupled synergistic catalysts fabrication strategy is presented to break the uniform electronic distribution,thus enhancing the intrinsic catalytic ***,atomically dispersed fe-N_(x) sites supported on N/s-doped mesoporous carbon(NsC)coupled with fes@C core-shell nanoparticles(FAs-NsC@950) is synthesized by a facile hydrothermal reaction and subsequent *** to the presence of an in situ-grown conductive graphitic layer(shell),the fes nanoparticles(core) effectively adjust the electronic structure of single-atom fe sites and facilitate the ORR kinetics via short/long-range coupling ***,FAs-NsC@950displays a more positive half-wave potential(E_(1/2)) of 0.871 V with a significantly boosted ORR kinetics(Tafel slope=52.2 mV dec^(-1)),outpacing the commercial Pt/C(E_(1/2)=0.84 V and Tafel slope=54.6 mV dec^(-1)).As a bifunctional electrocatalyst,it displays a smaller bifunctional activity parameter(ΔE) of 0.673 V,surpassing the Pt/C-RuO_(2) combination(ΔE=0.724 V).Besides,the FAs-NsC@950-based zincair battery(ZAB) displays superior power density,specific capacity,and long-term cycling performance to the Pt/C-Ir/C-based *** work significantly contributes to the field by offering a promising strategy to enhance the catalytic activity of sACs for ORR,with potential implications for energy conversion and storage technologies.

关键词： fe-N_(x)sites Core-shell fes@C synergistic interactions Oxygen reduction reaction Zn-air battery

In^(3+)-doped sr_(2)fe_(1.5)Mo_(0.5)O_(6−δ)cathode with improved performance for an intermediate-temperature solid oxide fuel cell

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Nano Research 2024年第1期17卷 407-415页

作者： Yumei ma Lijie Zhang Kang Zhu Binze Zhang Ranran Peng Changrong Xia Ling Huang state Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830046China Department of materials science and Engineering University of Science and Technology of ChinaHefei 230026China

Promoting the oxygen reduction reaction(ORR)is critical for commercialization of intermediate-temperature solid oxide fuel cells(IT-sOFCs),where sr_(2)fe_(1.5)Mo_(0.5)O_(6)−δ(sFM)is a promising cathode by working as a mixed ionic and electronic *** this work,doping of In^(3+)greatly increases the oxygen vacancy concentration and the content of adsorbed oxygen species in sr_(2)fe_(1.5)Mo_(0.5−x)InxO_(6−δ)(sFMInx),and thus effectively promotes the ORR *** a typical example,sFMIn_(0.1)reduces the polarization resistance(R_(p))from 0.089 to 0.046Ω∙cm^(2)at 800°C,which is superior to those doped with other metal *** addition,sFMIn0.1 increases the peak power density from 0.92 to 1.47 W∙cm^(−2)at 800°C with humidified H_(2)as the fuel,indicating that In3+doping at the Mo site can effectively improve the performance of sOFC cathode material.

关键词： solid oxide fuel cell cathode In3+doping oxygen reduction reaction(ORR) sr_(2)fe_(1.5)Mo_(0.5)O_(6-δ)

Microstructures,corrosion behavior and mechanical properties of as-cast Mg-6Zn-2X(fe/Cu/Ni)alloys for plugging tool applications

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International Journal of Minerals,Metallurgy and materials 2024年第4期31卷 697-711页

作者： Baosheng Liu Jiali Wei shaohua Zhang Yuezhong Zhang Pengpeng Wu Daqing Fang Guorui ma school of materials science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China state Key Laboratory for Mechanical Behavior of materials Xi’an Jiaotong UniversityXi’an 710049China Intelligent Equipment Research and Development Center Zhuhai Institute of Advanced Technology Chinese Academy of SciencesZhuhai 519080China Advanced materials Research Institute Zhuhai Dingmei Medical Technology Co.Ltd.Zhuhai 519000China

Mg-6Zn-2X(fe/Cu/Ni)alloys were prepared through semi-continuous casting,with the aim of identifying a degradable magnesium(Mg)alloy suitable for use in fracturing balls.A comparative analysis was conducted to assess the impacts of adding Cu and Ni,which result in finer grains and the formation of galvanic corrosion *** electronic microscopy examination revealed that precipitated phases concentrated at grain boundaries,forming a semi-continuous network structure that facilitated corrosion penetration in Mg-6Zn-2Cu and Mg-6Zn-2Ni *** corrosion was observed in Mg-6Zn-2fe,while galvanic corrosion was identified as the primary mechanism in Mg-6Zn-2Cu and Mg-6Zn-2Ni *** the tests,the Mg-6Zn-2Ni alloy exhibited the highest corrosion rate(approximately 932.9 mm/a)due to its significant potential *** testing showed that Mg-6Zn-2Ni alloy possessed suitable ultimate compressive strength,making it a potential candidate material for degradable fracturing balls,effectively addressing the challenges of balancing strength and degradation rate in fracturing applications.

关键词： magnesium alloys microstructure micro-galvanic corrosion mechanical properties

Effects of fe solid solute on grain boundaries of bi-crystal Cu: A molecular dynamics simulation

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Nano materials science 2024年第1期6卷 86-95页

作者： shuohan Yang Hongwei Bao Huizhong Bai Yan Li Haodong Xu fei ma state Key Laboratory for Mechanical Behavior of materials Xi’an Jiaotong UniversityXi’an710049ShaanxiChina

Grain boundaries(GBs)play a crucial role on the structural stability and mechanical properties of Cu and its *** this work,molecular dynamics(MD)simulations are employed to study the effects of fe solutes on the formation energy,excess volume,dislocations and melting behaviors of GBs in Cufe *** is illustrated that fe solute affects the structural stability of Cu GBs substantially,the formation energy of GBs is reduced,but the thickness and melting point of GBs are increased,that is,the structural stability of Cu GBs is significantly improved owing to the fe solutes.A strong scaling law exists between the formation energy,excess volume,thickness and melting point of ***,fe solid solute plays an important role in the characteristics of GBs in bi-crystal Cu.

关键词： Cufe alloy Grain boundary structural stability MD simulations

Geochemical elements in suspended particulate matter of Ensenada de La Paz Lagoon,Baja California Peninsula,Mexico:sources,distribution,mass balance and ecotoxicological risks

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Journal of Environmental sciences 2024年第2期136卷 422-436页

作者： sandra soledad Morales-García Pilar de Acacia Pérez-Escamilla suresh Babu sujitha Pichaimani Godwyn-Paulson andrés felipe Zuniga-Cabezas Muthuswamy Ponniah Jonathan Instituto Politécnico Nacional(IPN) Centro Mexicano para la Producción más Limpia(CMPL)Av.Acueducto s/nCol.Barrio la Laguna TicománDel Gustavo A.MaderoC.P.07340Ciudad de MéxicoMexico Instituto Politécnico Nacional(IPN) Escuela Superior de Ingeniería y Arquitectura(ESIA)Unidad Ticomán***án 600Delg.Gustavo A.MaderoC.P.07340Ciudad de México(CDMX)Mexico Instituto Politécnico Nacional(IPN) Centro Interdisciplinario de Investigaciones y Estudios sobre Medio Ambiente y Desarrollo(CIIEMAD)Calle 30 de Junio de 1520Barrio la Laguna TicománDel.Gustavo A.MaderoC.P.07340Ciudad de MéxicoMéxico

The present study aimed to evaluate multi-element concentrations(Al,As,Ca,Cd,Co,Cr,Cu,fe,Mg,Mn,Mo,Ni,Pb,sr)in suspended particulate material(sPM)collected from Ensenada de La Paz(ELP)lagoon,Baja California sur,Mexico in two different periods(september and may)to comprehend their origin,geochemical behavior,mass transfer and associated ecotoxicological *** 24 hr variation coefficient of volumetric sPM levels were found to be 51.7%in september and 40.5%in may,signifying the effects of oceanic *** calculated enrichment factor(EF)values for all the studied elements were of higher magnitude because of the high surface area and oxide nature of sPM,and in this study,Mo had the highest EF of 46.77 probably due to its origin from continental *** the ecotoxicological perspective,the integrated toxic risk index revealed low toxic risk to the benthic ***,the mean-ERM-Quotient calculated using the particulate concentrations of As,Cd,Cr,Cu,Ni,Pb indicated 9%probability of toxicity to *** comprehensive geochemical and ecotoxicological assessment of particulate metal concentrations in the ELP lagoon signify low to moderate contamination.

关键词： suspended particulate material Heavy metals Risk assessment mass transfer Ensenada de La Paz