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Densification and anticorrosion performances of vacuum evaporated aluminium coatings on NdFeB magnets

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Journal of Rare Earths 2021年第10期39卷 1238-1245,I0003页

作者： jun Huang Qing Liu Zhenyu Yang Guangqing Xu Pengjie Zhang jun lv wei Sun Bingshan Li Dongmei Wang Yucheng Wu School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China China International S&T Cooperation Base for Advanced Energy and Environmental Materials Hefei University of TechnologyHefei 230009China Key Laboratory of Advanced Functional Materials and Devices of Anhui Province Anhui Provincial International S&T Cooperation Base for Advanced Energy MaterialsHefei University of TechnologyHefei 230009China BGRIMM Technology Group Co. Ltd.Beijing 102600China National Engineering Research Center for Magnetic Materials Beijing 102600China

Al coated NdFeB magnets obtained by vacuum evaporation technique were densified by high energy ball milling *** surface morphology,metal composition and micro structure of the coatings were characterized by scanning electron microscopy,X-ray diffraction and X-ray photoelectron spectroscopy,*** anticorrosive properties were investigated by potentiodynamic polarization curves and neutral salt spray *** pores in the Al coatings of columnar crystals(Al) induced by the evaporation technique,were apparently filled in the following ball milling process,leading to the densification of Al coatings and the evident improvement of the anticorrosive *** treated with ball milling for 30 min,the sample achieves the best anticorrosive performances with the self-corrosion potential of-0.87 V,self-corrosion current density of 1.65 μA/cm^(2) and the neutral salt spray(NSS) time of 144 h(red rust).The improvement of the anticorro sive performances of vacuum evaporated Al coating mainly lies in the densification effect of the coating,which depends on different loading conditions of ball milling process.

关键词： Sintered NdFeB magnet Al coating Anticorrosive performances Vacuum evaporation Densification Rare earths

Localization and characterization of intermittent pollutant source in buildings with ventilation systems:Development and validation of an inverse model

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Building Simulation 2021年第3期14卷 841-855页

作者： Lingjie Zeng jun Gao Lipeng lv Bowen Du Yalei Zhang Ruiyan Zhang wei Ye Xu Zhang College of Environmental Science and Engineering Tongji UniversityShanghai200092China School of Mechanical Engineering Tongji UniversityShanghai 200092China Department of Civil and Mineral Engineering University of TorontoTorontoCanada

Terrorist attacks through building ventilation systems are becoming an increasing *** case pollutants are intentionally released in a building with mechanical ventilation systems,it is critical to localize the source and characterize its releasing *** inverse modeling studies have adopted the adjoint probability method to identify the source location and used the Tikhonov regularization method to determine the source releasing profile,but the selection of the prediction model and determination of the regularization parameter remain *** limitations can affect the identification accuracy and prolong the computational time *** address the difficulties in solving the inverse problems,this work proposed a Markov-chain-oriented inverse approach to identify the temporal release rate and location of a pollutant source in buildings with ventilation systems and validated it in an experimental *** the modified Markov chain,the source term was discrete by each time step,and the pollutant distribution was directly calculated with no *** forward Markov chain was reversed to characterize the intermittently releasing profile by introducing the Tikhonov regularization method,while the regularized parameter was determined by an automatic iterative discrepancy *** source location was further estimated by adopting the Bayes *** chamber experiments,the effectiveness of the proposed inverse model was validated,and the impact of the sensor performance,quantity and placement,as well as pollutant releasing curves on the identification accuracy of the source intensity was explicitly *** showed that the inverse model can identify the intermittent releasing rate efficiently and promptly,and the identification error for pollutant releasing curves with complex waveforms is about 20%.

关键词： intermittent source inverse identification Markov chain regularization parameter ventilation system

Optimization of preparation process of high-strength pellets from Panzhihua ilmenite concentrate

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Journal of Iron and Steel Research International 2023年第12期30卷 2391-2402页

作者： Gang-wei Zhou wei lv Fu-rong Chen Zheng-gen Liu Man-sheng Chu Xue-wei lv School of Metallurgy Northeastern UniversityShenyang110819LiaoningChina College of Materials Science and Engineering Chongqing UniversityChongqing400044China

The preparation of high-strength pellets from Panzhihua ilmenite concentrate is important for the hydrogen-rich smelting of titania slag and was *** effects of the magnetite concentrate and heating procedure including the pre-heating temperature and period as well as roasting temperature and period on the compressive strength of the roasted pellets were ***-strength ilmenite concentrate pellets(>2000 N)were prepared by optimizing the roasting *** addition of magnetite concentrate is beneficial for increasing the compressive strength of the Panzhihua ilmenite concentrate pellet by oxidizing hematite which filled the pseudobrookite particles,functioned as a bridge bond,and improved the interconnection between the *** compressive strength can reach up to 2900 N when the ilmenite concentrate pellet with 15%magnetite concentrate is pre-heated above 800℃ for 20 min and then roasted at 1250℃ for 20 *** addition,there is an overall upward trend in the compressive strength with an increase in the pre-heating temperature and period as well as the roasting temperature and *** micromorphology and strengthening consolidation mechanism of Panzhihua ilmenite concentrate pellets were also discussed.

关键词： Ilmenite concentrate Pelletizing Roasting Compressive strength-Pellet

Precise carbon structure control by salt template for high performance sodium-ion storage

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Journal of Energy Chemistry 2019年第4期28卷 101-106页

作者： Dong Qiu Tengfei Cao jun Zhang Si-wei Zhang Dequn Zheng Haoliang Wu wei lv Feiyu Kang Quan-Hong Yang Shenzhen Key Laboratory for Graphene-Based Materials Engineering Laboratory for Functionalized Carbon Materials Graduate School at ShenzhenTsinghua University Shenzhen Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen Institute(TBSI) Tsinghua University Nanoyang Group School of Chemical Engineering and Technology Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) TianjinUniversity

Carbon materials are considered to be one of the most promising anode materials for sodium-ion batteries(SIBs),but the well-ordered graphitic structure limits the intercalation of sodium ***,the sluggish intercalation kinetics of sodium ions impedes the rate ***,the precise structure control of carbon materials is important to improve the battery ***,a 3D porous hard-soft composite carbon(3DHSC)was prepared using the NaCl as the template and phenolic resin and pitch as carbon *** NaCl template restrains the growth of the graphite crystallite during the carbonization process,resulting in small graphitic domains with expanded interlayer spacing which is favorable for the sodium ***,the Na Cl templates help to create abundant mesopores and macropores for fast sodium ion *** porous structure and the graphite crystalline structure can be precisely controlled by simply adjusting the mass ratio of Na Cl,and thus,the suitable structure can be prepared to reach high capacity and rate performance while keeping a relatively high Coulombic ***,a high reversible capacity(215 mA h g^(-1)at 0.05 A g^(-1)),an excellent rate capability(97 mA h g^(-1)at 5 A g^(-1)),and a high initial Coulombic efficiency(60%)are achieved.

关键词： Sodium-ion batteries Salt-template 3D porous hard-soft composite carbon Anode Electrochemical performance

Control of chiral-optical activities by magnetic field based on the transformation of achiral binary crystals into chiral ternary crystals

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Science China Chemistry 2024年第7期67卷 2300-2305页

作者： Zhiyan Chen Yan lv wei Qin College of Physics Qingdao UniversityQingdao 266071China School of Physics State Key Laboratory of Crystal MaterialsShandong UniversityJinan 250100China Shandong Linuo Photovoltaic Hi-Tech Co. Ltd.Jinan 250100China

Multicomponent self-assembled chiral systems have attracted great attention due to their promising application in the area of spin-photonics and *** this work,through introducing an achiral third component into an achiral binary crystal,a chiral organic ternary crystal is fabricated,where both pronounced chiral-optical coupling and magnetic field dependence of chiral-optical activities are *** transformation of achiral structure into chiral structure generates a significant effect on the polarized state of light and the electron spin resonance ***,the coupling between circularly polarized photon and spin is observed in chiral ternary crystal with pronounced chiral orbit,where obvious magnetic field-transmissivity loop is ***,temperature could increase the magnitude of lattice parameters to lead to a larger helix radius to increase the chiral orbit ***,this work indicates that the further exploration of photon-chiral orbit-spin interactions in organic chiral ternary crystals is promising.

关键词： organic chiral ternary crystals chiral orbit chiral-optical activities magnetic field

Solid-state reaction of a CaO−V_(2)O_(5)mixture:A fundamental study for the vanadium extraction process

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International Journal of Minerals,Metallurgy and Materials 2021年第9期28卷 1462-1468页

作者： jun-yi Xiang Xin Wang Gui-shang Pei Qing-yun Huang Xue-wei lv College of Materials Science and Engineering Chongqing UniversityChongqing 400044China School of Metallurgy and Materials Engineering Chongqing University of Science and TechnologyChongqing 401331China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing 400044China

The aim of this study was to investigate the phase transformation and kinetics of the solid-state reaction of CaO−V_(2)O_(5),which is the predominant binary mixture involved in the vanadium recovery *** analysis,X-ray diffraction spectroscopy,scanning electron microscopy,and energy dispersive spectrometry were used to characterize the solid-state reaction of the *** extent of the solid reac-tion was derived using the preliminary quantitative phase analysis of the X-ray *** results indicate that the solid reaction of the CaO−V_(2)O_(5)mixture is strongly influenced by the reaction temperature and CaO/V_(2)O_(5)mole *** transformation of calcium vanadate in-volves a step-by-step reaction of CaO−V_(2)O_(5),CaO−CaV_(2)O_(6),and CaO−Ca_(2)V_(2)O7 depending on the CaO/V_(2)O_(5)mole *** kinetic data of the solid reaction of the CaO−V_(2)O_(5)(1:1)mixture followed a second-order reaction *** activation energy(Ea)and preexponential factor(A)were determined to be 145.38 kJ/mol,and 3.67×10^(8)min^(−1),respectively.

关键词： calcium vanadate vanadium extraction solid-state reaction kinetics

Anti-corrosion performance of Si-surface-alloying NdFeB magnets obtained with magnetron sputtering and thermal diffusion

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Journal of Rare Earths 2023年第8期41卷 1203-1210,I0003页

作者： Jin Tao Bang Liu Pengjie Zhang Guangqing Xu jun lv jun Huang Jian Yan wei Sun Bingshan Li Dongmei Wang Yucheng Wu School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China BGRIMM Technology Group Co. Ltd.Beijing 102600China National Engineering Research Center for Magnetic Materials Beijing 102600China Key Laboratory of Advanced Functional Materials and Devices of Anhui Province Anhui Provincial International S&T Cooperation Base for Advanced Energy MaterialsHefei University of TechnologyHefei 230009China

Si alloying in the surface layer of NdFeB magnets was realized by thermal diffusion combined with magnetron *** surface composition,phase structure and morphology of NdFeB(S-Si)specimens were characterized by an X-ray diffractometer,an X-ray photoelectron spectrometer and a field emission scanning electron microscope,*** corrosion resistance of bare NdFeB(S-Si)was analyzed by static full immersion corrosion test and electrochemical *** of sputtering and thermal diffusion on the microstructure and corrosion resistance of the surface layer were *** show that surface alloying layer can effectively improve the corrosion resistance of bare NdFeB with the optimized static total immersion corrosion test time in NdFeB(1S-Si)-800 of 36 h,which is much longer than that of the pristine NdFeB(less than 0.5 h).The E_(corr)of NdFeB(1S-Si)-800 positively shifts from-1.05 to-0.92 V,indicating that the corrosion tendency is obviously *** J_(corr)is1.45×10^(-6)A/cm^(2)which is 2 orders of magnitude lower than that of the pristine NdFeB(5.25×10^(-4)A/cm^(2)).The intergranular composite oxides existing in Nd-rich phase contribute to the enhancement of corrosion resistance of Si-surface-alloying NdFeB.

关键词： NdFeB magnets Si surface alloying Magnetron sputtering Thermal diffusion Corrosion resistance Rare earths

Rare earth passivation and corrosion resistance of zinc coated NdFeB magnets

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Journal of Rare Earths 2022年第2期40卷 302-308,I0005页

作者： Jing Chen Hongyi Yang Guangqing Xu Pengjie Zhang jun lv wei Sun Bingshan Lidi jun Huang Dongmei Wang Xia Shu Yucheng Wu School of Materials Science and Engineering.Hefei University of Technology Hefei 230009China China International S&T Cooperation Base for Advanced Energy and Environmental Materials Hefei University of TechnologyHefei 230009China Key Laboratory of Advanced Functional Materials and Devices of Anhui Province Anhui Provincial International S&T Cooperation Base for Advanced Energy MaterialsHefei University of TechnologyHefei 230009China BGRIMM Technology Group Co. Ltd.Beijing 102600China National Engineering Research Center for Magnetic Materials Beijing 102600China

Rare earth passivation was conducted on Zn coated NdFeB magnets by chemical reaction to enhance the corrosion resistance ***,micro structures and compositions of different passivated coatings were studied by X-ray diffraction,field emission scanning electron microscopy,and X-ray photoelectron spectroscopy,*** corrosion behavior was evaluated by electrochemical measurement and neutral salt spray *** results show that the rare earth passivation can enhance the corrosion resistance of Zn coated NdFeB *** the concentration of cerium nitrate is 5 g/L,the passivated specimens can achieve the longest NSS time of 360 h,which is 144 h longer than that of the pristine Zn/NdFeB *** passivation layer on the Zn coating surface contributes to the enhancement of the magnets’corrosion resistance.

关键词： Sintered NdFeB magnets Rare earth passivation Zn coating Electroplating Corrosion resistance

Tear inflammation related indexes after cataract surgery in elderly patients with type 2 diabetes mellitus

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World Journal of Clinical Cases 2023年第2期11卷 385-393页

作者： jun lv Cheng-Jian Cao wei Li Shuang-Le Li jun Zheng Xiu-Li Yang Department of Optometry North Sichuan Medical CollegeNanchong 637000Sichuan ProvinceChina Zigong Academy of Medical Sciences Zigong First People’s HospitalZigong 643000Sichuan ProvinceChina FB Biologie Philipps-Universitaet MarburgMarburg 35043Germany Department of Ophthalmology Zigong First People’s HospitalZigong 643000Sichuan ProvinceChina

BACKGROUND Quantitative studies on the changes in inflammation-related content in tears,especially the effect of diabetes,are *** this study,we measured the preoperative and postoperative tear inflammatory mediator levels in cataract patients,focusing on the expression of inflammatory factors in postoperative cataracts in the diabetic,and investigated the effect of drugs on the control of postoperative *** To study the expression of inflammatory factors in elderly people with type 2 diabetes after cataract *** Patients with a mean age of 70.3±6.3 years were divided into group A(composed of elderly patients with cataracts and type 2 diabetes,n=20 eyes)and group B(patients with age-related cataract,n=20 eyes).Their tears were collected before each operation and on days 1 and 3,and weeks 1,2,3,and 4 ***(150μL)was dropped into the conjunctival sac of the surgical eye,followed by oculogyration in four *** fluid in the conjunctival sac was extracted using a sterile syringe and stored in Eppendorf tubes at-80°C until *** expression levels of matrix metalloproteinase-2(MMP-2),MMP-9,tissue inhibitor of metalloproteinase-1(TIMP-1),TIMP-2,interleukin-6(IL-6),and IL-20 in tear fluid were measured using enzyme-linked immunosorbent *** The postoperative expression levels of MMP-2,MMP-9,TIMP-2,IL-6,and IL-20 in group A were significantly higher than those in group B,whereas the concentration of TIMP-1 in group A remained lower than that in group *** levels of MMP-2 and IL-6 in both groups continuously increased until the peak in the first postoperative week,and then gradually decreased over the next three ***,MMP-2 declined to a lower level than that preoperatively at week 4,but IL-6 decreased to the same level as that *** level of MMP-9 peaked in the first two weeks postoperative and then returned to the same level as 1-day *** concentration of TIMP-1 pos

关键词： Type 2 diabetes mellitus Elderly patients Cataract surgery Tear inflammation-related indicators Temporal changes Prognosis