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Science china(Physics,Mechanics & Astronomy) 2022年第11期65卷 125-131页

作者： Haiyang Yang Qi wang Junwu Huang Zhouliang wang Keqi xia chao cao Mingliang Tian Zhuan xu Jianhui Dai Yuke Li School of Physics and Hangzhou Key Laboratory of Quantum Matters Hangzhou Normal UniversityHangzhou 311121China Anhui Province Key Laboratory of condensed Matter Physics at Extreme conditions High Magnetic Field LaboratoryChineseAcademyof SciencesHefei 230031China Departmentof Physics Zhejiang UniversityHangzhou 310058China Zhejiang Province Key Laboratory of Quantum Technology and Device Zhejiang UniversityHangzhou 310027China

Anomalous Nernst effect, as a thermal partner of anomalous Hall effect, is particularly sensitive to the Berry curvature anomaly near the Fermi level, and has been used to probe the topological nature of quantum materials. In this work, we report the observation of both effects in the ferromagnetic Weyl-semimetal Fe_(3-δ)GeTe_(2) with tunable Fe vacancies. With decreasing Fe vacancies,the anomalous Hall conductivity evolves as a function of the longitudinal conductivity from the hopping region to the region where the intrinsic Berry curvature contribution dominates. concomitant evolutions in the anomalous Nernst signal and the anomalous off-diagonal thermoelectric coefficient are observed below the curie temperature, displaying a unique sign change caused by the Fe vacancies. combining these results with first-principles calculations, we argue that the Fe-vacancy concentration plays a unique role in simultaneously tuning the chemical potential and ferromagnetism, which in turn controls the Berry curvature contribution in this family of ferromagnetic topological semimetals.

关键词： thermoelectronic effect Hall effect quantum transport topological Weyl semimetal

corrosion resistance of composite coating on magnesium alloy using combined microarc oxidation and inorganic sealing

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中国有色金属学会会刊：英文版 2012年第S3期22卷 760-763页

作者： YANG Wei wang Ai-ying JIANG Bai-ling Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences School of Material Science and Engineering Xi'an University of Technology

The combined microarc oxidation (MAO) and inorganic sealing process was used to deposit a composite coating to improve the corrosion resistance of AZ31 magnesium *** surface morphologies of the resulting duplex coatings were studied by ***,the corrosion resistance of the coated Mg alloy substrates was investigated using electrochemical workstation and dropping corrosion *** results show that the composite coating surface consists of Mg,Si,O and *** is difficult to deposit inorganic coating on a thick MAO coating *** the composite coating was solidified by cO2 under 175 °c,it exhibits a better corrosion resistance than the MAO monolayer,owing to the thick and compact inorganic coating.

关键词： AZ31 magnesium alloy microarc oxidation composite coating microstructure corrosion resistance

Pinches-Induced Transport Reduction in Reversed Shear/Optimized Shear Tokamak Plasmas

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chinese Physics Letters 1999年第9期16卷 662-664页

作者： QIU xiao-ming wang Ai-ke Southwestern Institute of Physics (P.O.Box 432)Chengdu 610041

The analytical formulas for anomalous particle and ion thermal diffusivities,Dte and xti,are derived on the basis of the two-fluid equations of our previous paper[***.15(1998)721].The two formulas involve five factors:(reversed/optimized)magnetic shear LB(r),E x B sheared velocity VE(r),where E is from the gradient of the ion pressure Pi,and the three ways of coupling between them,L-1B(dVE/dr),L-1B VE,and ***,where k is the LB-dependent *** is found that the five factors can produce turbulent particle-and heat-pinch,i.e.,Dtexticore region of tokamaks,and hence the effective particle and ion thermal diffusivities,Deeff and xieff,reduce significantly in that *** numerical results for Deeff and xieff are in good agreement with experimental values.

关键词： Shear particle reversed

Effects of initial grain size and strain on grain boundary engineering of high-nitrogen crMn austenitic stainless steel

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International Journal of Minerals,Metallurgy and Materials 2018年第8期25卷 922-929页

作者： Zhen-hua wang Jian-jun Qi Wan-tang Fu School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China HBIS Group Technology Research Institute Shijiazhuang 050023China

18 Mn18 cr0.5 N steel with an initial grain size of 28–177 μm was processed by 2.5%–20% cold rolling and annealing at 1000°c for 24 h,and the grain boundary character distribution was examined via electron backscatter *** strain(2.5%) favored the formation of low-Σ *** this strain,the fraction of low-Σ boundaries was insensitive to the initial grain ***,specimens with fine initial grains showed decreasing grain size after grain boundary engineering *** fraction of low-Σ boundaries and the(Σ9 + Σ27)/Σ3 value decreased with increasing strain; furthermore,the specimens with fine initial grain size were sensitive to the ***,the effects of the initial grain size and strain on the grain boundary engineering were discussed in detail.

关键词： grain boundary engineering grain boundary character distribution grain size strain austenitic stainless steel

Stability of γ′ multimodal microstructure in a Ni-based powder metallurgy superalloy

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Science china(Technological Sciences) 2018年第12期61卷 1824-1828页

作者： ZHANG Ming LIU GuoQuan wang Hao HU BenFu School of Materials Science and Engineering University of Science and Technology Beijing

Multimodal size distribution of γ′ phase was obtained in a slow-cooling experiment following supersolvus solution treatment(1191°c). The morphology of the secondary γ′ particles exhibited splitting and protrusion instabilities. In the subsequent aging process(815°c), reverse coarsening was observed, i.e., the average precipitate size decreased with increasing aging *** coarsening slows the coarsening rate of the precipitates, increases the hardness of the alloy, and greatly improves the morphological stability of the γ′ phase.

关键词： Nickel alloys γ′ phase multimodal size distribution microstructure stability

Inductive effect of Ti-doping in Fe_(2)O_(3)enhances the photoelectrochemical water oxidation

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Science china chemistry 2023年第7期66卷 2091-2097页

作者： Yumei Lin Yan wang Hongxia wang Jingjing wang xiaofeng Wu Jan P.Hofmann Giulio Gorni Victor A.de la Pena O'Shea Freddy E.Oropeza Kelvin H.L.Zhang State Key Laboratory of Physical chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Surface Science Laboratory Department of Materials and Earth SciencesTechnical University of DarmstadtDarmstadt 64287Germany cELLS-ALBA Synchrotron Barcelona 08290Spain Institute of Optics(IO-cSIc) c/Serrano 121Madrid 28006Spain Photoactivated Processes Unit IMDEA Energy InstituteMadrid 28935Spain

Hematite(α-Fe_(2)O_(3))is an ideal oxide semiconductor candidate for photoelectrochemical(PEc)water *** of Fe_(2)O_(3)is known to benefit the PEc water oxidation efficiency,but despite extensive research efforts,the underlying mechanism still remains *** this work,we report a comprehensive study on the relationship between the electronic structure,interfacial reaction kinetics and PEc activity of Ti-doped Fe_(2)O_(3)*** results show that the interfacial charge transfer efficiency at the Fe_(2)O_(3)/electrolyte interface is the main factor in the significant increase of the PEc activity of doped Fe_(2)O_(3).Electrochemical impedance spectroscopy reveals that the interfacial charge transfer efficiency is determined by energy overlap between the water oxidation potential and energy distribution of an intermediate surface state that has been identified as Fe^(IV)=O groups on Fe_(2)O_(3)surface generated during PEc ***,the potential energy distribution of this intermediate surface state can be modulated by Ti doping,and a shift towards a more positive potential of the intermediate surface state increases the overlap with the water oxidation potential and thus enhances the kinetics of charge transfer for PEc water *** origin of such potential energy modulation is traced to the inductive effect from Ti-doping on the Fe^(3+)/Fe^(4+)redox transition and the Fe-O bond *** results provide new insight into the mechanism for the doping effect on the PEc water splitting,introducing new strategies to optimize the PEc activity by tuning the redox properties of active metal oxides.

关键词： hematite surface states doping photoelectrochemical water splitting electronic structure

Ultrasonic-assisted pyrolyzation fabrication of reduced SnO2-x/g-c3N4 heterojunctions： Enhance photoelectro- chemical and photocatalytic activity under visible LED light irradiation

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Nano Research 2016年第7期9卷 1969-1982页

作者： Kai Li xiaoqiao Zeng Shanmin Gao Lu Ma Qingyao wang Hui xu Zeyan wang Baibiao Huang Ying Dai Jun Lu college of chemistry and Materials Science Ludong University Yantai 264025 China chemical Sciences and Engineering Division Argonne National Laboratory Argonne IL 60439 USA State Key Laboratory of crystal Materials Shandong University Jinan 250100 China x-Ray Science Division Argonne National Laboratory Argonne IL 60439 USA

Novel SnO2-x/g-c3N4 heterojunction nanocomposites composed of reduced SnO2 nanoparticles and exfoliated g-cBN4 nanosheets were prepared by a convenient one-step pyrolysis method. The structural, morphological, and optical properties of the as-prepared nanocomposites were characterized in detail, indicating that the aggregation of g-c3N4 nanosheets was prevented by small, well-dispersed SnO2_x nanoparticles. The ultraviolet-visible spectroscopy absorption bands of the nanocomposites were shifted to a longer wavelength region than those exhibited by pure SnO2 or g-cgN4. The charge transfer and recombination processes occurring in the nanocomposites were investigated using linear scan voltammetry and electrochemical impedance spectroscopy. Under 30-W visible-light-emitting diode irradiation, the heterojunction containing 27.4 wt.% SnO2-x exhibited the highest photocurrent density of 0.0468 ***-2, which is 33.43 and 5.64 times larger than that of pure SnO2 and g-c3N4, respectively. The photocatalytic activity of the heterojunction material was investigated by degrading rhodamine B under irradiation from the same light source. Kinetic study revealed a promising degradation rate constant of 0.0226 min^-1 for the heterojunction containing 27.4 wt.% SnO2-x, which is 32.28 and 5.79 times higher than that of pure SnO2 and g-c3N4, respectively. The enhanced photoelectrochemical and photocatalytic performances of the nanocomposite may be due to its appropriate SnO2x content and the compact structure of the junction between the SnO2-x nanoparticles and the g-c3N4 nanosheets, which inhibits the recombination of photogenerated electrons and holes.

关键词： reduced SnO2x-x g-c3N4 heterojunctions photoelectrochemical light-emitting diodesource

High-dynamics pulse-shaped signal simulation based on polynomial-based interpolation filters

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Science china(Information Sciences) 2017年第10期60卷 264-266页

作者： Shaozhong LU Yongqing wang Sheng LI Siliang WU School of Information and Electronics Beijing Institute of Technology

Dear editor,Baseband signal shaping is widely applied in satellite communication,GNSS,and TT&c systems as a fundamental technique[1].These systems work in high-speed dynamic environments,causing data rate variations b... 详细信息

关键词： High-dynamics pulse-shaped signal simulation based on polynomial-based interpolation filters PSF FIR Figure SRc

A method for recovery of iron,titanium,and vanadium from vanadium-bearing titanomagnetite

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International Journal of Minerals,Metallurgy and Materials 2018年第2期25卷 131-144页

作者： Yi-min Zhang Li-na wang De-sheng chen Wei-jing wang Ya-hui Liu Hong-xin Zhao Tao Qi University of chinese Academy of Sciences Beijing 100049China National Engineering Laboratory for Hydrometallurgical cleaner Production Technology Beijing 100190China Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures： low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°c, a residence time of 2 h, a molar ratio of c/O of 1.7, and a sodium carbonate addition of 70 wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.

关键词： recovery vanadium titanomagnetite direct reduction sodium oxidation smelting separation water leaching

Modeling capacitance voltage characteristic of TiW/p-InP Schottky barrier diode

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chinese Physics B 2018年第9期27卷 500-503页

作者： Yi-Dong wang Jun chen School of Electronic and Information Engineering Soochow UniversitySuzhon 215006China

The capacitance-voltage（c-V） characteristic of the TiW/p-InP Schottky barrier diodes（SBDs） is analyzed considering the effects of the interface state（N（ss））, series resistance（Rs）, and deep level defects. The c-V of the Schottky contact is modeled based on the physical mechanism of the interfacial state and series resistance effect. The fitting coefficients α andβ are used to reflect the N（ss） and Rs on the c-V characteristics, respectively. The α decreases with the increase of frequency,while β increases with the increase of frequency. The capacitance increases with the increase of α and the decrease of β.From our model, the peak capacitance and its position can be estimated. The experimental value is found to be larger than the calculated one at the lower voltage. This phenomenon can be explained by the effect of deep level defects.

关键词： Schottky barrier diode interface state series resistance