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Nodal superconducting gap in LiFeP revealed by NMR:Contrast with LiFeAs

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Chinese Physics B 2021年第4期30卷 113-118页

作者： A F Fang R zhou H Tukada J Yang z Deng X C Wang C q Jin Guo-qing zheng Department of Physics Beijing Normal UniversityBeijing 100875China Institute of Physics Chinese Academy of Sciencesand Beijing National Laboratory for Condensed Matter PhysicsBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China Department of Physics Okayama UniversityOkayama 700-8530Japan

Identifying the uniqueness of FeP-based superconductors may shed new lights on the mechanism of superconductivity in ***,we report nuclear magnetic resonance(NMR) studies on LiFeP and LiFeAs which have the same crystal structure but different pnictogen *** NMR spectrum is sensitive to inhomogeneous magnetic fields in the vortex state and can provide the information on the superconducting pairing symmetry through the temperature dependence of London penetration depth λ_(L).We find that λ_(L) saturates below T~0.2 T_(C) in LiFeAs,where T_(C) is the superconducting transition temperature,indicating nodeless superconducting ***,by using a two-gaps model,we simulate the temperature dependence of λ_(L) and obtain the superconducting gaps of LiFeAs,as Δ_(1)=1.2 kB T_(C) and Δ_(2)=2.8 k_(B)T_(C),in agreement with previous result from spin-lattice *** LiFeP,in contrast,λ_(L) does not show any saturation down to T~0.03 T_(C),indicating nodes in the superconducting gap ***,we demonstrate that strong spin fluctuations with diffusive characteristics exist in LiFeP,as in some cuprate high temperature superconductors.

关键词： iron-based superconductor nuclear magnetic resonance superconducting pairing symmetry spin fluctuations

THE ACqM THEORETICAL CALCULATION OF LOW-LYING EXCITED STATES FOR HeH

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原子与分子物理学报 1990年第4期7卷 1565-1570页

作者： q.q.GOU z.Y.Huang 等 TheIustituteofAtomicandMolecularPhysics ChengduUniversityofScienceandTechnologyChengduChina TheIust

The Low-lying excited states of HeH have been calculated by arrangement channel quantum mechanics(ACqM),The calculated potential curves,equilibrium geometry,*** energy *** vibration frequency ω0 and quadratic force c... 详细信息

关键词： HeH 低激发态 ACqM理论计算

VISCO-PLASTIC CONSTITUTIVE MODEL FOR UNIAXIAL AND MULTIAXIAL RATCHETING AT ELEVATED TEMPERATURES

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 431-436页

作者： G.z.Kang q.Gao J.zhang Dept. of Applied Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 ChinaDept. of Applied Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 ChinaDept. of Applied Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 China

Based on the experimental results of the ratcheting for SS304 stainless steel, a new visco-plastic cyclic constitutive model was established to describe the uniaxial and multiaxial ratcheting of the material at room and elevated temperatures within the framework of unified visco-plasticity. In the model, the temperature dependence of the ratcheting was emphasized, and the dynamic strain aging occurred in the temperature range of 4 00-600℃ for the material was taken into account particularly. Finally, the prediction capability of the developed model was checked by comparing to the corresponding experimental results.

关键词： constitutive model ratcheting elevated temperature multiaxial loading

Magnetic and Electrical Behavior of MnTe_(1-x)Sb_x Alloys

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Journal of Materials Science & Technology 2011年第1期27卷 64-68页

作者： X.He Y.q.zhang z.D.zhang Shenyang National Laboratory for Materials Science Institute of Metal Researchand International Center for Materials PhysicsChinese Academy of SciencesShenyang 110016China

The structure,specific heat,magnetic and electrical properties of MnTe1-xSbx（x=0,0.1,0.15,0.2 and 0.25） alloys have been *** MnTe1-xSbx alloys crystallize in a hexagonal NiAs-type structure,and the impurity of MnSb phase appears when x≥*** MnTe0.9Sb0.1 compound exhibits ferrimagnetic behavior with hysteresis loops even at 350 K,showing that the magnetic properties of MnTe compound are very sensitive to little compositional *** ferromagnetism in the MnTe1-xSbx alloys with higher Sb contents may be attributed to the impurity of MnSb *** dispersive X-ray spectroscopy analysis on the MnTe0.9Sb0.1 compound indicates that Sb is very difficult to dope into the lattice of *** the anomaly of resistivity at 300 K of MnTe0.9Sb0.1 and the peak of specific heat around 304 K of all the alloys are thought to be related with the antiferromagnetic interactions of MnTe-based lattice.

关键词： Electronic transport property Hysteresis loop Specific heat

Analysis of vibration reduction level in an 8/6 switched reluctance machine by active vibration cancellation

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Journal of zhejiang University-Science C(Computers and Electronics) 2010年第10期11卷 808-816页

作者： Xu LIU zai-ping PAN z. q. zHU School of Electrical Engineering Zhejiang University Hangzhou 310027 China Department of Electronic and Electrwal Engmeermg University of Sheffield Sheffield S1 3JD UK

This paper proposes an analytical model for predicting the maximum vibration reduction level in a four-phase 8/6 switched reluctance machine(SRM) by employing active vibration cancellation(AVC),one of the most effective and convenient methods for reducing the vibration and acoustic noise produced by *** on the proposed method,the factors that influence the vibration reduction level are analyzed in *** relationships between vibration and noise reduction levels at resonance frequency and rotor speed are ***,it is shown that a large damping factor will lead to smaller vibration reduction level with AVC while,in contrast,a large resonance frequency will increase the vibration reduction *** finite element analyses and experiments were carried out on a prototype 8/6 SRM to validate the proposed method.

关键词： Active vibration cancellation Analytical model Switched reluctance machine Vibration

Surface modification of tungsten oxide by oxygen vacancies for hydrogen adsorption

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Journal of Materials Science & Technology 2022年第22期117卷 23-35页

作者： q.zhang F.W.Tang z.zhao z.R.Nie X.Y.Song Faculty of Materials and Manufacturing Key Laboratory of Advanced Functional MaterialsMinistry of Education of ChinaBeijing University of TechnologyBeijing 100124China

A model for describing the adsorption process of hydrogen on surface of tungsten oxide was proposed based on the first-principle calculations. Multiple factors such as type of active surface, adsorption site and distribution of oxygen vacancies were considered to evaluate the hydrogen adsorption capability of tungsten oxide. The adsorption Gibbs free energies, electronic structures and bonding characteristics under various conditions were examined to reveal the influence of oxygen vacancies on the surface. It is found that the capability of hydrogen adsorption of tungsten oxide can be significantly enhanced by adjusting the oxygen vacancy on the outermost layer of certain active surfaces. The modeling predicts that the surface structure stability and gas adsorption ability of tungsten oxide can be simultaneously improved through the formation of W–H bonds. The proposed strategy for moderating surface provides a new approach to obtain excellent gas-sensitive metal oxide materials.

关键词： Metal oxide Gas-sensitive material Surface adsorption Oxygen vacancy First-principles calculation

Improving high-temperature mechanical properties of cast CrFeCoNi high-entropy alloy by highly thermostable in-situ precipitated carbides

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Journal of Materials Science & Technology 2021年第13期72卷 29-38页

作者： X.W.Liu N.Gao J.zheng Y.Wu Y.Y.zhao q.Chen W.zhou S.z.Pu W.M.Jiang z.T.Fan State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621999China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China School of Materials Engineering Purdue UniversityWest LafayetteIN 47907USA Southwest Technology and Engineering Research Institute Chongqing 400039China Center for Electron Microscopy Wuhan UniversityWuhan 430072China

The Cr Fe Co Ni high-entropy alloy(HEA)exhibits excellent mechanical properties at lower temperatures due to its low stacking-fault energy,however,its medium-and high-temperature strengths are still *** consideration of the potential diversified applications,more strengthening approaches except for the previously proposed L12 phase hardening deserve further exploration due to its rapid coarsening tendency at high ***,we achieved significant high-temperature strengthening of the cast Cr Fe Co Ni HEA by in-situ precipitation of highly thermostable *** with 0.5 at.%and 1 at.%niobium and carbon were prepared by simple casting processes,*** cast,solute solution and aging.A highly thermostable microstructure was formed,which comprises very coarse grains accompanied with extensive thermostable carbide precipitates embedded,including submicrometer coherent Nb C particles in grain interiors and intergranular coherent M_(23)C_(6)*** high thermostability of microstructure,which is beneficial for the high-temperature loading,is ascribed to the synergy of lacking growth driving force and zenner pinning effect by the *** properties tested at 673,873 and1073 K show that the yield strength and ultimate tensile strength are significantly increased by Nb/C doping,along with the elongation escalation at higher *** strengthening is mainly due to the precipitation hardening of carbide particles.

关键词： High-entropy alloy Carbides Precipitation High-temperature property Strengthening

Template-free Fabrication and Luminescent Characterization of Highly Uniform and Monodisperse Y_2O_2S:Sm^(3+) Hollow Submicrospheres

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Journal of Materials Science & Technology 2012年第7期28卷 666-672页

作者： S.q. Deng z.P. Xue Y.H. Yang q. Yang Y.L. Liu Department of Chemistry Jinan University Guangzhou 510632 China

Well dispersed and homogeneous Y2O2S：Sm3＋ hollow submicrospheres were successfully achieved by a template- free solvothermal method combining with a postcalcining process. The crystalstructure and particle morphology were investigated by the X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectra, scanning and transmission electron microscopy （SEM and TEM）, respectively. A possible growth mechanism was proposed to reveal the formation process. Luminescence properties of the Y202S：Sm3＋ long-lasting phosphor were an- alyzed by measuring the excitation spectra, emission spectra, afterglow decay curve and thermoluminescence curve. The excitation spectra indicated that the phosphor could be excited effectively by the ultraviolet-light emitting diode （UV-LED） or blue LED, and the emission spectra showed that the phosphor could emit red light from 600 to 650 nm.

关键词： Yttrium oxysulfide Hollow submicrosphere Luminescence Long-lasting phosphor

IMPROVEMENT OF CARBIDE MORPHOLOGY ANDMECHANICAL PROPERTIES OF Cr12MoV STEELS

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Acta Metallurgica Sinica(English Letters) 2000年第5期13卷 1053-1058页

作者： Cui, X.H. Jiang, q.C. Wang, S.q. He, z.M. Sch. of Mat. Sci. and Eng. Jilin Univ. of Technol. Changchun 130025 China

Compared with conventional cast Cr12MoV steel and forged Cr12MoV steels, carbide morphology and properties of modified cast Cr12MoV steels were investigated by performing hardness test, impact test, fracture toughness test, fatigue crack propagation test, metallographic examination and quantitatively metallographic analysis. The results indicate that the carbide morphology in modified cast steel is characterized by uniformly-distributed granular carbide, which is different from that of conventional cast steel, but similar to that of forged steel. the impact toughness of modified cast steel is distinctly increased to 12.75 J/cm2 from 6.8 J/cm2 in the conventional cast steel with networked carbide, because of carbide granulation. Furthermore, The fracture toughness and fatigue-crack-propagation threshold of modified cast steel are not only higher than that of the conventional cast steel, but also higher than that of the forged steels.

关键词： Alloys Carbides Mechanical properties Morphology