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Applied Mathematics and Mechanics(English Edition) 2022年第3期43卷 355-370页

作者： Chi xu Yang LI Mingyue LU Zhendong dai College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Jiangsu Provincial Key Laboratory of Bionic Functional Materials Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In this work,the size-dependent buckling of functionally graded(FG)Bernoulli-Euler beams under non-uniform temperature is analyzed based on the stressdriven nonlocal elasticity and nonlocal heat *** utilizing the variational principle of virtual work,the governing equations and the associated standard boundary conditions are systematically extracted,and the thermal effect,equivalent to the induced thermal load,is explicitly assessed by using the nonlocal heat conduction *** stressdriven constitutive integral equation is equivalently transformed into a differential form with two non-standard constitutive boundary *** employing the eigenvalue method,the critical buckling loads of the beams with different boundary conditions are *** numerically predicted results reveal that the growth of the nonlocal parameter leads to a consistently strengthening effect on the dimensionless critical buckling loads for all boundary ***,the effects of the influential factors pertinent to the nonlocal heat conduction on the buckling behavior are carefully examined.

关键词： size effect stress-driven nonlocal model constitutive boundary condition nonlocal heat conduction functionally graded(FG)beam buckling load

Products and production routes for the catalytic conversion of seed oil into fuel and chemicals: a comprehensive review

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Science China Chemistry 2015年第7期58卷 1110-1121页

作者： Mazloom Shah Jian-Jun dai Qing-xiang Guo Yao Fu Anhui Province Key Laboratory of Biomass Clean Energy Department of Chemistry University of Science and Technology of China

With the depletion of fossil resources, there is a need to find alternative resources of fuels and chemicals. The use of renewable feedstock such as those from seed oil processing is one of the best available resources that have come to the fore-front recently. This paper critically analyzes and highlights major factors in the biodiesel industry, such as seeds oil composition, production methods, properties of biodiesel, problems and potential solutions of using vegetable seed oil, the composition, quality and effective utilization of crude glycerol, the catalytic conversion of glycerol into possible fuels and chemicals.

关键词： seed oil catalytic conversion biodiesel glycerol fuels and chemicals

Cyber-physical Power System Modeling for Timing-driven Control of Active Distribution Network

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Journal of Modern Power Systems and Clean Energy 2020年第3期8卷 549-556页

作者： Yun Wang Dong Liu Xiaochun xu Hui dai Electrical Engineering Department of Shanghai Jiao Tong University China State Grid Shanghai Electric Power Research Institute China State Grid Jiangsu Huai’an Power Supply Company China

In a cyber-physical power system, active distribution network(ADN) facilitates the energy control through hierarchical and distributed control system(HDCS). Various researches have dedicated to develop the control strategies of primary devices of ADN. However, an ADN demonstration project shows that the information transmission of HDCS may cause time delay and response lag, and little model can describe both the ADN primary device and HDCS as a cyber-physical system(CPS). In this paper, a hybrid system based CPS model is proposed to describe ADN primary devices, control information flow, and HDCS. Using the CPS model, the energy process of primary devices and the information process of HDCS are optimized by model predictive control(MPC) methodology to seamlessly integrate the energy flow and the information flow. The case study demonstrates that the proposed CPS model can accurately reflect main features of HDCS, and the control technique can effectively achieve the operation targets on primary devices despite the fact that HDCS brings adverse effects to control process.

关键词： Active distribution network(ADN) cyber-physical system(CPS) hybrid system hierarchical and distributed control system

Theoretical Studies on the Fe-M Interactions and 31p NMR in Fe（CO）3（EtPhPpy）2MX2 （X=NCS, SCN, CI; M=Zn, Cd, Hg）

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Chinese Journal of Chemical Physics 2008年第5期21卷 438-444页

作者： Xiao-xuan Huang xuan xu Mei-xiang Xie School of Chemistry and Environment Key Lab of Technology on Electrochemical Energy Storage and Power Generation in Guangdong Universities South China Normal University Guangzhou 510006 China

To study the Fe-M interactions and their effects on 31p NMR, the structures of Fe（CO）3（EtPhPpy）2 1, Fe（CO）3（EtPhPpy）2M（NCS）2 （2： M=Zn, 3： M=Cd, 4： M=Hg） and Fe（CO）3（EtPhPpy）2CdX2 （5： X=C1, 6： X=SCN） were investigated by density functional theory （DFT） PBE0 method. The stabilities S of complexes follow S（2）〉S（3）〉S（4） and S（3）,.~S（6）〉S（5）, indicating that 6 is stable and may be synthesized. The complexes with thiocyanate are more stable than that with chloride in Fe（CO）3（EtPhPpy）2CdX2. The strength I of Fe-M interactions follows I（2）≈I（3）〈I（4）. The Fe-Cd interactions of 3 and 6, which contain thiocyanate, are stronger than that of 5 with chloride. The charge-transfer, which enhances with the increasing of Fe-M interaction strength, comes from Et, Ph, py, CO groups towards P, Fe, and M atoms. Because the delocalization of thiocyanate disperses the charge of M2＋, the charge-transfer of the complexes with thiocyanate is stronger than that with chloride. There is a a-bond between Fe and Hg atoms in 4. However, in binuclear complexes except 4, the Fe-M interactions act as nFe→nM, σP-Fe→nM and σC-Fe→nM delocalization, and the N-M interactions mainly act as nN→nM delocalization. In binuclear complexes, due to the Fe→M interactions, the strong σFe--C→σ＊Fe--p or σFe-Hg→σ＊Fe--I2 delocalization and the charge-transfer, the electron density on P nucleus is increased, and thus upfield 31p chemical shifts are caused （compared with mononuclear complex 1）.

关键词： DFT 31p NMR Metal-metal interaction Nature bond orbital

Synthesis and Crystal Structure of a Dinuclear Cu(Ⅱ) Complex [Cu(C_(13)H_9N_2O)Cl]_2·(CH_3CN)_2 with Ligand 2-Benzimidazol

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Chinese Journal of Structural Chemistry 2007年第2期26卷 149-152页

作者： LI Qing-xiang YANG xiang-Liang xu Hui-Bi Hubei Key Laboratory of Novel Chemical Reactor andGreen Chemical Technology Wuhan Institute of Technology Wuhan 430073 China College of Life Science Huazhong University of Science and Technology Wuhan 430074 China

A new dinuclear copper complex, [Cu（C13HgN2O）Cl]2.（CH3CN）2 （C30H24C12Cu2N6O2）, has been synthesized and characterized by X-ray structure determination. It crystallizes in the triclirile system, space group P1, with a = 7.6677（14）, b = 9.2375（17）, c = 11.227（2） ]A, α = 81.338（3）,β = 88.173（4）, γ = 66.199（3）°, V = 718.9（2） ]A^3, Z = 1, Mr = 698.53, F（000） = 354, Dc = 1.613 g/cm^3, μ（MoKa） = 1.705 mm^-1, the final R = 0.0645 and wR = 0.1364 for 2474 unique reflections with 1809 observed ones （I 〉 20（I））. In the title complex, each copper（H） atom is located at the center of a distorted tetrahedron consisting of four coordinate atoms （one nitrogen atom, two oxygen anions, and one chlorine atom）. Two copper（Ⅱ） atoms are bridged by two oxygen anions （O（1） and O（la）） of two phenolates to form a Cu（Ⅱ）-Cu（Ⅱ） binuclear entity, and the distance between two copper（Ⅱ） atoms is 3.0144（15） A.

关键词： 2-benzimidazol phenolate Cu(Ⅱ) complex crystal structure

(Y0.25Yb0.25Er0.25Lu0.25)2(Zr0.5Hf0.5)2O7: A defective fluorite structured high entropy ceramic with low thermal conductivity and close thermal expansion coefficient to Al2O3

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Journal of Materials Science & Technology 2020年第4期39卷 167-172页

作者： Zifan Zhao Heng Chen Huimin xiang Fu-Zhi dai Xiaohui Wang Wei xu Kuang Sun Zhijian Peng Yanchun Zhou School of Engineering and Technology China University of GeosciencesBeijing 100083China Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing 100076China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Shanghai Chenhua Science and Technology Corporation Limted Shanghai 201804China

Al2O3f/Al2O3 ceramic matrix composites(CMC)are promising candidate materials of blades and combustor liners of future gas turbines in light of their higher temperature capability,higher environmental stability and oxidizing-free capacity[1–3].Nevertheless,grain growth,sintering and creep deformation at high operation temperatures are still serious problems for Al2O3f/Al2O3 ceramic matrix composites,which can lead to a reduction in the strength and damage tolerance[2].Moreover,Al2O3 can be corroded by the high temperature water vapor in combustion environments and yields volatile products,such as Al(OH)3[4].Consequently,environmental barrier coatings(EBCs)are necessary for Al2O3f/Al2O3 ceramic matrix composites,which can protect Al2O3f/Al2O3 CMC from high temperature and flowing combustion gas corrosion and thus increase the high temperature capability and the service life of components.

关键词： Al2O3f/Al2O3 ceramic matrix conductivity close thermal expansion

Shear anisotropy： Tuning high temperature metal hexaborides from soft to extremely hard

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Journal of Materials Science & Technology 2017年第11期33卷 1371-1377页

作者： Yanchun Zhou Fuzhi dai Huimin xiang Bin Liu Zhihai Feng Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Material & Processing Technology Beijing 100076China School of Materials Science and Engineering Shanghai University Shanghai 200444 China

Easy machining into sharp lending edge, nose tip and complex shape components plays a pivotal role in the application of ultrahigh temperature ceramics in hypersonic vehicles, wherein low and controllable hardness is a necessary parameter to ensure the easy machinability. However, the mechanism that driving the hardness of metal hexaborides is not clear. Here, using a combination of the empirical hardness model for polycrystalline materials and density functional theory investigation, the hardness dependence on shear anisotropic factors of high temperature metal hexaborides has been established. It has come to light that through controlling the shear anisotropic factors the hardness of polycrystalline metal hexaborides can be tailored from soft and ductile to extremely hard and brittle, which is underpinned by the degree of chemical bonding anisotropy, i.e., the difference of B-B bond within the B;octahedron and that connecting the B;octahedra.

关键词： Microhardness Electronic structure Elastic constant Borides Structural ceramics

Hot-embossing fabrication of chalcogenide glasses rib waveguide for mid-infrared molecular sensing

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Chinese Physics B 2017年第2期26卷 274-279页

作者： Ting-Yang Yan xiang Shen Rong-Ping Wang Guo-xiang Wang Shi-xun dai Tie-Feng xu Qiu-Hua Nie Laboratory of Infrared Material and Devices Advanced Technology Research Institute Ningbo University Ningbo 315211 China Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province Ningbo 315211 China The Australian National University Canberra ACT 2600 Australia

Chalcogenide glasses have shown promise in fabricating mid infrared（MIR） photonic sensing devices due to their excellent optical properties in MIR. In addition, the glass transition temperature of chalcogenide glasses are generally low,making them ideal to create the high-throughput patterns of micro-scale structures based on hot embossing that is alternative to the standard lithographic technology. In this paper, we outline the research progress in the chalcogenide waveguide based on the hot embossing method, and discuss the problems remaining to be solved and the possible solutions.

关键词： chalcogenide glasses hot embossing rib waveguides MIR sensing

High strength and high porosity YB2C2 ceramics prepared by a new high temperature reaction/partial sintering process

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Journal of Materials Science & Technology 2019年第12期35卷 2883-2891页

作者： Heng Chen Huimin xiang Fuzhi dai Jiachen Liu Yanchun Zhou Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education School of Materials Science and EngineeringTianjin UniversityTianjin300072China Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing100076China

Porous ultrahigh temperature ceramics(UHTCs) are potential candidates as reusable thermal protection materials of transpiration cooling system in scramjet engine. However, low strength and low porosity are the main limitations of porous UHTCs. To overcome these problems, herein, a new and simple in-situ reaction/partial sintering process has been developed for preparing high strength and high porosity porous YB2C2. In this process, a simple gas-releasing in-situ reaction has been designed, and the formation and escape of gases can block the shrinkage during sintering process, which is favorable to increase the porosity of porous YB2C2. In order to demonstrate the advantages of the new method, porous YB2C2 ceramics have been fabricated from Y2O3, BN and graphite powders for the first time. The as-prepared porous YB2C2 ceramics possess high porosity of 57.17%–75.26% and high compressive strength of 9.32–34.78 *** porosity, sintered density, radical shrinkage and compressive strength of porous YB2C2 ceramics can be controlled simply by changing the green density. Due to utilization of graphite as the carbon source, the porous YB2C2 ceramics show anisotropy in microstructure and mechanical behavior. These features render the porous YB2C2 ceramics promising as a thermal-insulating light-weight component for transpiration cooling system.

关键词： Ultrahigh temperature ceramics(UHTCs) YB2C2 Porous ceramics Microstructure Strength

Aerodynamic characteristics of a pitching airfoil with leading-edge morphing

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Chinese Journal of Aeronautics 2024年第7期37卷 81-92页

作者： Chaoyuan WEN Yuting dai Yuntao xu Chao YANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Tianmushan Laboratory Hangzhou 311115China

This paper focuses on the effect of the phase offset of Leading-Edge(LE)morphing on the aerodynamic characteristics of a pitching NACA0012 *** an unstretched camber and using polynomial interpolation,an explicit expression for LE nonlinear morphing is proposed and implemented for the large pitching motion of the *** field results and aerodynamic forces are obtained by solving the unsteady Reynolds-averaged Navier-Stokes equations for both the airfoil’s pitching motion and LE ***,the index of instantaneous aerodynamic power is used to quantify the work done by the airflow in a dynamic *** to the instantaneous aerodynamic power and energy map,which denotes the energy transfer between the airfoil’s oscillation and flow field,the airfoil is subject to stall *** results show that LE morphing with an optimal phase offset of 315°reduces the energy extraction from the flow field,suppressing the stall flutter *** optimal phase offset is effective at different pitching axis positions of the *** results signify that LE morphing can suppress stall flutter by advancing the occurrence of the first LE vortex and increasing the nose-down moment during the upstroke period.

关键词： Aerodynamics Computational fluid dynamics Leading-edge morphing OpenFOAM Dynamic stall Dynamic mesh