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Acta Mathematica Sinica,English Series 2013年第10期29卷 1993-1996页

作者： Deng Ming XU Sino-European Institute of Aviation Engineering Civil Aviation University of China

It is proved that the Auslander-Reiten conjecture is true for local Artin algebras with radical cube zero.

关键词： Local algebras projective modules Auslander-Reiten conjecture

On Behaviors of Functionally Graded SMAs under Thermo-Mechanical Coupling

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Acta Mechanica Solida Sinica 2016年第1期29卷 46-58页

作者： Bingfei Liu Pengcheng Ni Wei Zhang Airport College Civil Aviation University of China Sino-European Institute of Aviation Engineering Civil Aviation University of China

An analytical solution is obtained for the Functionally Graded Shape Memory Alloy （FG-SMA） composites subjected to thermo-mechanical coupling. Young＇s modulus and thermal expansion coefficient of the material are assumed to vary in different forms of power function through the thickness, with the Poisson＇s ratio being constant. An SMA constitutive model is combined with the averaging techniques of composite to determine the mechanical properties of the FG-SMA composites. Different phase transformation steps and the corresponding stress distributions through the thickness direction are given. The results show that the average stresses decrease as the transformations proceed.

关键词： functionally graded SMAs phase transformation constitutive model

Effects of C impurities on the elastic properties of NiAl intermetallics

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Progress in Natural Science:Materials International 2014年第6期24卷 637-641页

作者： Xuelan Hu Ji Ma Hongwei Dou Yifan Niu Yanfeng Zhang Qinggong Song Sino-European Institute of Aviation Engineering Civil Aviation University of China College of Science Civil Aviation University of China

The atomic configuration and ductility of Ni Al intermetallics affected by C impurity have been studied with a first-principles pseudo-potential method. The calculation results indicate that for the substitutional cases, C prefers to replace Ni other than Al in most of the cases except for the Ni-rich case. As compared with the interstitial cases, the C atom can be more easily occupy the Ni-rich octahedron position in both of the Ni-rich and Al-rich cases. The brittleness will be decreased and the ductility will be increased after the Ni Al intermetallics doped with the impurity C atom.

关键词： Ni Al intermetallics C impurity Elastic properties First-principles

On the Deformation of Lie–Yamaguti Algebras

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Acta Mathematica Sinica,English Series 2015年第6期31卷 938-946页

作者： Jie LIN Liang Yun CHEN Yao MA Sino-European Institute of Aviation Engineering Civil Aviation University of China School of Mathematics and Statistics Northeast Normal University

The deformation theory of Lie-Yamaguti algebras is developed by choosing a suitable cohomology. The relationship between the deformation and the obstruction of Lie-Yamaguti algebras is obtained.

关键词： Lie-Yamaguti algebra algebraic deformation cohomology

Effect of P impurity on mechanical properties of NiAl Σ5 grain boundary:From perspectives of stress and energy

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Chinese Physics B 2018年第3期27卷 391-396页

作者：胡雪兰赵若汐邓江革胡艳敏宋庆功 Sino-European Institute of Aviation Engineering Civil Aviation University of ChinaTianjin 300300China College of Science Civil Aviation University of ChinaTianjin 300300China

In this paper, we employ the first-principle total energy method to investigate the effect of P impurity on mechanical properties of NiA1 grain boundary （GB）. According to ＂energy＂, the segregation of P atom in NiA1E5 GB reduces the cleavage energy and embrittlement potential, demonstrating that P impurity embrittles NiA1E5 GB. The first-principle computational tensile test is conducted to determine the theoretical tensile strength of NiA1E5 GB. It is demonstrated that the maximum idea/tensile strength of NiA1E5 GB with P atom segregation is 144.5 GPa, which is lower than that of the pure NiA1E5 GB （164.7 GPa）. It is indicated that the segregation of P weakens the theoretical strength of NiA1E5 GB. The analysis of atomic configuration shows that the GB fracture is caused by the interfacial bond breaking. Moreover, P is identified to weaken the interactions between A1-A1 bonds and enhance Ni-Ni bonds.

关键词： NiA1Z5 grain boundary P impurity first principles mechanical properties

Effect of P impurity on NiAlΣ5 grain boundary from first-principles study

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Chinese Physics B 2017年第2期26卷 121-126页

作者：胡雪兰赵若汐罗阳宋庆功 Sino-European Institute of Aviation Engineering Civil Aviation University of China Tianjin 300300 China College of Science Civil Aviation University of China Tianjin 300300 China

First-principles calculations based on the density functional theory（DFT） and ultra-soft pseudopotential are employed to study the atomic configuration and charge density of impurity P in Ni Al Σ5 grain boundary（GB）. The negative segregation energy of a P atom proves that a P atom can easily segregate in the Ni Al GB. The atomic configuration and formation energy of the P atom in the Ni Al GB demonstrate that the P atom tends to occupy an interstitial site or substitute a Al atom depending on the Ni/Al atoms ratio. The P atom is preferable to staying in the Ni-rich environment in the Ni Al GB forming P–Ni bonds. Both of the charge density and the deformation charge imply that a P atom is more likely to bond with Ni atoms rather than with Al atoms. The density of states further exhibits the interactions between P atom and Ni atom, and the orbital electrons of P, Ni and Al atoms all contribute to P–Ni bonds in the Ni Al GB. It is worth noting that the P–Ni covalent bonds might embrittle the Ni Al GB and weakens the plasticity of the Ni Al intermetallics.

关键词： NiAlΣ5 grain boundary impurity effect first principles

Four Families of Nontrivial Product Elements in the Stable Homotopy Groups of Spheres

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Chinese Annals of Mathematics,Series B 2022年第3期43卷 459-472页

作者： Linan ZHONG Jianguo HONG Hao ZHAO Department of Mathematics Yanbian UniversityYanji 133002JilinChina Sino-European Institute of Aviation Engineering Civil Aviation University of ChinaTianjin 300300China School of Mathematical Sciences South China Normal UniversityGuangzhou 510631China

In this paper,the authors introduce a new effective method to compute the generators of the E-term of the May spectral sequence.This helps them to obtain four families of non-trivial product elements in the stable hom... 详细信息

关键词： Stable homotopy groups of spheres Adams spectral sequence May spectral sequence

Explicit Symplectic Geometric Algorithms for Quaternion Kinematical Differential Equation

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IEEE/CAA Journal of Automatica Sinica 2018年第2期5卷 479-488页

作者： Hong-Yan Zhang Zi-Hao Wang Lu-Sha Zhou Qian-Nan Xue Long Ma Yi-Fan Niu School of Information Science and Technology Hainan Normal University Haikou 571158 China the Department of engineering Sino-European Institute of Aviation Engineering Civil Aviation University of China Tianjin 300300 China Civil aviation University of China Tianjin 300300 China

Solving quaternion kinematical differential equations(QKDE) is one of the most significant problems in the automation, navigation, aerospace and aeronautics literatures. Most existing approaches for this problem neither preserve the norm of quaternions nor avoid errors accumulated in the sense of long term time. We present explicit symplectic geometric algorithms to deal with the quaternion kinematical differential equation by modelling its time-invariant and time-varying versions with Hamiltonian systems and adopting a three-step strategy. Firstly,a generalized Euler's formula and Cayley-Euler formula are proved and used to construct symplectic single-step transition operators via the centered implicit Euler scheme for autonomous Hamiltonian system. Secondly, the symplecticity, orthogonality and invertibility of the symplectic transition operators are proved rigorously. Finally, the explicit symplectic geometric algorithm for the time-varying quaternion kinematical differential equation, i.e., a non-autonomous and non-linear Hamiltonian system essentially, is designed with the theorems proved. Our novel algorithms have simple structures, linear time complexity and constant space complexity of computation. The correctness and efficiencies of the proposed algorithms are verified and validated via numerical simulations.

关键词： Linear time-varying system navigation system quaternion kinematical differential equation(QKDE) real-time computation symplectic method

Toughening Effects through Optimizing Cell Structure and Deformation Behaviors of Al–Mg Foams

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Acta Metallurgica Sinica(English Letters) 2022年第12期35卷 2014-2026页

作者： Hao Yu Xudong Yang Weiting Li Xudong Rong Siyuan Guo Lishi Ma Lizhuang Yang Junwei Sha Naiqin Zhao Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin UniversityTianjin 300350China Sino-European Institute of Aviation Engineering Civil Aviation University of ChinaTianjin 300300China School of Materials Science and engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Advanced Ceramics and Machining Technology Ministry of EducationTianjin 300350China

As widely used protective materials,the application of Al foams is still limited by their low intrinsic mechanical properties caused by the brittleness of struts.The introduction of Mg is recently demonstrated effective to improve the mechanical performance of Al foams;however,the mechanism of Mg modification is still not clear.In this work,Al-Mg foams are developed through a powder metallurgy process with excellent compression performance and high energy absorption capacity.The effects of Mg modification on the cell structure,toughness,and deformation behavior are investigated systematically.As a result,the small cell size of~1.8 mm and the high sphericity of 0.92 are achieved with 5% of Mg addition,delivering high compression stress of 8.5±0.43 MPa and energy absorption capacity of 6.9±0.36 MJ/m^(3),simultaneously.The synergistic mechanism for the improved mechanical performance is also demonstrated to be the combination of stress transfer and plastic deformation behavior of cells.The results provide a new strategy to develop high-performance foam materials by improving toughness and further promote the practical application.

关键词： Powder metallurgy Aluminum foam Al-Mg alloy Plastic deformation Cell structure

Effects of supersonic fine particle bombarding on thermal cyclic failure lifetime of thermal barrier coating

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Journal of Harbin institute of Technology(New Series) 2010年第4期17卷 521-526页

作者：陈亚军林晓娉王志平王立君纪朝辉董允 School of Materials Science and engineering Tianjin University Sino-European Institute of Aviation Engineering Civil Aviation University of China School of Materials Science and engineering Northeastern University at Qinhuangdao

Thermal barrier coating ( TBC) consisting of a NiCoCrAlY bond coat ( BC) and a ZrO2-8 wt. % Y2O3 topcoat ( TC) was fabricated on the nickel-base superalloy by air plasma spray ( APS) . The BC was treated by supersonic fine particle bombarding ( SFPB) . Thermal cyclic failure and residual stress in thermally grown oxide ( TGO) scale were studied by SEM with EDS and ruby fluorescence spectroscopy ( RFS) . As shown in the results,after treated by SFPB,thickening of TGO was relatively slow,which reduced the level of growth stress. The TBC with SFPB treatment was still remained well undergoing 350 times of thermal cycle. However,after thermal cycle with the same times,the separation of TC was observed in TBC without SFPB treatment. The residual stress analysis by RFS showed that the residual stress of SFPB-treated TBC increased with the increasing number of thermal cycle. The residual stress of conventional TBC reached a value of 650 MPa at 350 times of cycle and that of SFPB-treated TBC only reached 532 MPa at 400 times of cycle. The BC with SFPB treatment after 400 times of cycle was analyzed by RFS,the high stress value was not observed in local thickened region of TGO. Thermal cycling resistance of TBC can be improved by the SFPB technology.

关键词： supersonic fine particle bombarding TGO thermal cycles residual stress TBC