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Phase Stability,Elastic,Thermo-physical and Electronic Properties of Hexa-(Mo,Cr,W)_2C from First-principles Calculations

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Journal of Iron and Steel Research International 2016年第10期23卷 1096-1103页

作者： Di WU wan-tang FU Yong LI Chun-xu wanG Jing-lin tang College of Mechanical Engineering Yanshan University Institute for Structural Materials Central Iron and Steel Research Institute State Key Laboratory of Metastable Materials Science and Technology Yanshan University

Phase stability,elastic properties,thermo-physical properties,as well as electronic properties of hexa-（Mo,Cr,W）2C carbides were investigated by first-principles *** results indicated that the Mo8C4,Mo7Cr1C4,Mo7W1C4,Mo6W2C4,and Mo6W1Cr1C4 are stable and the stability follows the sequence：Mo6W1Cr1C4〉Mo7W1C4〉Mo7Cr1C4〉 Mo6W2C4〉 ***6W1Cr1C4 shows the highest stability,deformation resistance and hardness.G/B（shear modulus/bulk modulus）and Poisson′s ratio of the stable hexa-（Mo,Cr,W）2C are all larger than 1.75 and 0.26,respectively,which indicates that they are all *** anisotropies are mainly due to the different Vogit shear modulus/Reuss shear modulus;the mechanical anisotropy of Mo7Cr1C4 is the largest,and that of Mo8C4 is the ***,the obtained Debye temperatureΘDand heat capacity Cpindicate that Mo6W2C4 possesses the best thermal conductivity（ΘD=497.72K）,while Mo7Cr1C4 and Mo6W2C4possess the largest heat capacity when the temperature is in the range of 0-10 Kand larger than 10 K,*** the electronic property analysis,the doped Cr and W atoms can not only participate in orbitals hybridization themselves but also enhance the orbitals hybridization between Mo and C atoms,which can reinforce the interatomic interactions.

关键词： hexa (Mo,Cr, W)2C carbide elastic property electronic structure thermo-physical property first-principles calculation

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

Coupled KdV Equations and Their Explicit Solutions Through Two-Dimensional Hamiltonian System with a Quartic Potential

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Communications in Theoretical Physics 2008年第6期49卷 1379-1382页

作者： CAO Jian-Li ZHANG Hua JIAO wan-tang College of Science Henan University of Technology Zhengzhou 450052 China Henan Economy and Trade Vocational College Zhengzhou 450053 China

Based on the second integrable ease of known two-dimensional Hamiltonian system with a quartie potentiM, we propose a 4 × 4 matrix speetrM problem and derive a hierarchy of coupled KdV equations and their Hamiltonian structures. It is shown that solutions of the coupled KdV equations in the hierarchy are reduced to solving two compatible systems of ordinary differentiM equations. As an application, quite a few explicit solutions of the coupled KdV equations are obtained via using separability for the second integrable ease of the two-dimensional Hamiltonian system.

关键词： coupled KdV equations integrable system explicit solution

Acceptorless dehydrogenative amination of alkenes for the synthesis of N-heterocycles

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Science China Chemistry 2022年第7期65卷 1330-1337页

作者： Jia-Lin Tu wan tang Shi-Hui He Ma Su Feng Liu Jiangsu Key Laboratory of Neuropsychiatric Diseases and Department of Medicinal Chemistry College of Pharmaceutical SciencesSoochow UniversitySuzhou 215123China Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Catalytic amination of alkenes is one of the most attractive reactions for the construction of complex heterocycles with nitrogen centers. Herein, we present that synergistic photoredox and cobaloxime catalysis allows for highly efficient and mild dehydrogenative reactions between various NH nucleophiles and di-, tri-, and tetrasubstituted alkenes in the absence of external oxidants, thus enabling access to an array of N-heterocycles. Notably, both Z-and E-alkene-containing N-heterocycles are accessible. Mechanistic studies indicated that the Z-cinnamyl derivatives could be generated by photocatalytic E to Z alkene isomerization through an energy transfer process. Moreover, we find that sluggish energy transfer could inhibit the E to Z alkene isomerization process, thus offering the cinnamyl derivatives with E-selectivity. Our results highlight the benefits of the reactions using dual photoredox and cobaloxime catalysis to lead to diverse N-heterocycles.

关键词： nitrogen-centered radical alkene amination photoredox cyclization N-heterocycle

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Effect of Cyclic Annealing on Microstructure and Mechanical Properties of Medium Carbon Steel

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Journal of Iron and Steel Research International 2016年第2期23卷 145-150页

作者： Zhi-qing LÜ Hui-fang ZHANG Qing MENG Zhen-hua wanG wan-tang FU College of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina State Key Laboratory of Metastable Material Science and Technology Yanshan UniversityQinhuangdao 066004HebeiChina

The microstructure and mechanical properties of medium carbon steel after cyclic heat treatment were in- vestigated. The effects of cyclic numbers and long time annealing on the microstructure and mechanical properties of the experimental steel were compared. A short duration （5 min） holding at 1023 K （above A1 temperature） and a short-duration （3 min） holding at 893 K are adopted in each cyclic heat treatment. The spheroidization is accelerated during cyclic heat treatment, and the spheroidizing ratio grows with cyclic numbers. After 12-cycle heat treatments, there are few incompletely spheroidized regions in the specimens, and cementite lamellae mostly change into cement- ite particles. The morphological character of cementite for 12 cycles is similar to that undergoing annealing for 10 h at 973 K. The strength of the experimental steel after 5-cycle heat treatment is the lowest in the following cyclic heat treatment, but it is still higher than that of specimens with subcritical annealing over a long period （10 h）. After 12- cycle heat treatment, the strength of the experimental steel is close to that of the normalized steel, and the plasticity is the best in all heat treated specimens.

关键词： rapid spheroidizing mechanical property cyclic annealing cementite medium carbon steel

Effect of Boron on Delayed Fracture Resistance of Medium-Carbon High Strength Spring Steel

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Journal of Iron and Steel Research International 2007年第6期14卷 53-57,67页

作者： NIE Yi-hong HUI Wei-jun FU wan-tang WENG Yu-qing State Key Lab of Metastable Material Science and Technology Yanshan University Qinhuangdao 066004 Hebei China Institute for Structural Material Central Iron and Steel Research Institute Beijing 100081 China Chinese Society for Metals Beijing 100711 China

The delayed fracture behavior of medium carbon high strength spring steel containing different amounts of boron （0. 000 5%, 0. 001 6 %） was studied using sustained load delayed fracture test. The results show that delayed fracture resistance of boron containing steels is higher than that of conventional steel 60Si2MnA at the same strength level and it increases with the increase of boron eontent from 0. 000 5% to 0. 001 6%. The delayed fracture mode is mainly intergranular in the boron containing steels tempered at 350℃, which indicates that the addition of boron does not change the fracture character. However, the increase of boron content enlarges the size of the crack initia tion area. Further study of phase analysis indicates that most boron is in solid solution, and only a very small quantity of boron is in the M3 （C, B） phase.

关键词： borons delayed fracture resistances medium-carbon high strength spring steel

On testing proportional odds assumptions for proportional odds models

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General Psychiatry 2023年第3期36卷 214-219页

作者： Anqi Liu Hua He Xin M Tu wan tang Department of Bostaistis and Data Science Tulane UniversityNew OrleansLouisianaUSA Department of Epidemiology Tulane UniversityNew OrleansLouisianaUSA Division of Biostatistics and Bioinformatics Herbert Wertheim School of Public Health and Human Longevity ScienceUC San DiegoLa JollaCaliforniaUSA

Proportional odds models are commonly used to model ordinal responses,but the proportional odds assumption may not hold in practice,leading to biased *** such as score,Wald and likelihood ratio(LR)have been proposed to evaluate the proportional odds assumption based on models without the *** has proposed an independent binary model-based Wald-type test,and Wolfe and Gould have extended the idea to propose an LR-type *** paper provides a brief review of the Brant and Wolfe-Gould tests for evaluating the proportional odds assumption and evaluates their performance through simulation studies and a real data *** programs are provided in SAS,SPSS and Stata to facilitate the implementation of these tests using standard statistical software *** study highlights the importance of evaluating the proportional odds assumption when using proportional odds models for ordinal *** sample programs provided in this paper make it easy for researchers to apply these tests in their own analyses using standard statistical software packages.

关键词： Gould testing apply

Strength and Microstructure of Mortar Containing Glass Powder and/or Glass Aggregate

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Journal of Wuhan University of Technology(Materials Science) 2016年第6期31卷 1302-1310页

作者：刘数华 wanG Shu ZHOU Wei LI Lihua XIAO Henglin WEI Jianpeng tang wan State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China China Construction Ready Mixed Concrete Co. Ltd. Wuhan 430000 China School of Civil Engineering and Architecture Hubei University of Technology Wuhan 430068 China

The compressive strength of mortar containing glass powder（GP） and/or glass aggregate（GA） was tested, and its microstructure was also studied by thermogravimetric and differential thermal analysis（TG-DTA）, scanning electron microscopy（SEM）, energy dispersive spectroscopic analysis（EDX）, and X-ray diffraction（XRD） techniques. The incorporation of GA would decrease the compressive strength of the mortar in the absence of GP. Incorporating both GA and GP could change the hydration environment, promote pozzolanic reaction of GP and improve the compressive strength. GP does not lead to but can effectively control ASR（Alkali Silica Reaction）. GP and GA do not transform the type of hydrates, but have a great influence on the amounts of hydration products, and generate more calcium silicate hydrate（C-S-H gel） with lower Ca/Si ratio. GP and GA with good gradation will make the microstructure denser.

关键词： glass powder glass aggregate mortar strength microstructure

Excellent mechanical properties and resistance to cavitation erosion for an ultra-low carbon Cr Mn N stainless steel through quenching and partitioning treatment

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International Journal of Minerals,Metallurgy and Materials 2018年第5期25卷 547-553页

作者： Ze-an Zhou wan-tang Fu Zhe Zhu Bin Li Zhong-ping Shi Shu-hua Sun State Key Laboratory of Metastable Materials Science and Technology Yanshan University

The retained austenite content(RAC),the mechanical properties,and the resistance to cavitation erosion(CE)of the00Cr13Mn8Mo N steel after quenching and partitioning(Q&P)processing were *** results show that the Q&P process affected the RAC,which reached the maximum value after partitioning at 400°C for 10 *** tensile strength of the steel slightly decreased with increasing partitioning temperature and ***,the elongation and product of strength and elongation first increased and then *** sample partitioned at 400°C for 10 min exhibited the optimal property:a strength-ductility of 23.8 GPa?%.The resistance to CE for the 00Cr13Mn8Mo N steel treated by the Q&P process was improved due to work hardening,spalling,and cavitation-induced martensitic transformation of the retained austenite.

关键词： CrMnN steel quenching and partitioning process retained austenite mechanical property cavitation erosion