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多场耦合下压电圆筒的热电弹性瞬态响应
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作者 戴庆华 戴宏亮 王熙 《深圳大学学报(理工版)》 EI CAS 北大核心 2006年第2期122-127,共6页
提出一种求解在热冲击和电势激励载荷作用下,正交各向异性压电圆筒结构的热电弹性动力学耦合问题的解析方法.通过实例给出在热冲击和电势激励载荷作用下,正交各向异性压电圆筒内的应力、电位移和电势的瞬态响应历程及其分布规律.
关键词 热冲击 电势激励载荷 热电弹性动力学 正交各向异性压电圆筒
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First principles investigation of binary intermetallics in Mg-Al-Ca-Sn alloy:Stability,electronic structures,elastic properties and thermodynamic properties 被引量:8
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作者 王峰 孙士杰 +3 位作者 于波 张峰 毛萍莉 刘正 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第1期203-212,共10页
The structural stability, electronic structures, elastic properties and thermodynamic properties of the main binary phases Mg_(17)Al_(12), Al_2Ca, Mg_2 Sn and Mg_2 Ca in Mg-Al-Ca-Sn alloy were determined from the ... The structural stability, electronic structures, elastic properties and thermodynamic properties of the main binary phases Mg_(17)Al_(12), Al_2Ca, Mg_2 Sn and Mg_2 Ca in Mg-Al-Ca-Sn alloy were determined from the first-principles calculation. The calculated lattice parameters are in good agreement with the experimental and literature values. The calculated heats of formation and cohesive energies show that Al_2Ca has the strongest alloying ability and structural stability. The densities of states(DOS), Mulliken electron occupation number, metallicity and charge density difference of these compounds are given. The elastic constants of Mg_(17)Al_(12), Al_2Ca, Mg_2 Sn and Mg_2 Ca phases are calculated, and the bulk moduli, shear moduli, elastic moduli and Poisson ratio are derived. The calculations of thermodynamic properties show that the Gibbs free energies of Al_2Ca and Mg_2 Sn are lower than that of Mg_(17)Al_(12), which indicates that Al_2Ca and Mg_2 Sn are more stable than Mg_(17)Al_(12) phase. Hence, the heat resistance of Mg-Al-based alloys can be improved by adding Ca and Sn additions. 展开更多
关键词 Mg-Al alloy first-principles calculation electronic structure elastic properties thermodynamic properties
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Study on structural,mechanical and thermodynamic properties of TiAl alloy under high pressure based on first-principles
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作者 邓世杰 赵宇宏 +1 位作者 文志勤 韩培德 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2017年第2期147-153,共7页
The effect of pressure on structural, mechanical properties as well as the temperature dependence of thermodynamic properties of TiAl alloy are investigated by implementing first-principles calculations. The results s... The effect of pressure on structural, mechanical properties as well as the temperature dependence of thermodynamic properties of TiAl alloy are investigated by implementing first-principles calculations. The results show that the volume decrea-ses with the pressure increasing. We calculated the CtJ at various pressures and all the results satisfy mechanical stability crite-ria, thus the TiAl alloy is mechanically stable. The elastic constants? bulk modulus and shear modulus calculated are well in a-greement with the calculated values at zero the pressure. The bulk modulus and shear modulus increase with the pressure in-creasing, which reflects the deformation resistance, and accordingly, deformation resistance can be strengthened with the in-crease of pressure. The brittle nature of TiAl alloy turns to ductile nature in 10 - 20 GPa . The Debye temperature, linear ther-mal expansion and heat capacity are calculated using the quasi-harmonic Debye model under the pressure ranging from 0 to 50 GPa and the temperature ranging from 0 to 1 000 K, which are useful to investigate the effect of temperature and pressure on thermodynamic parameters. Finally, electronic structure is calculated at various pressures,and it can be found that the peak intensity decreases with increasing pressure and the the strength of d-d orbital of Ti is weakened but the ductility is enhanced. 展开更多
关键词 TiAl alloy FIRST-PRINCIPLES crystal structure elastic properties thermodynamic properties electronic structure
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Analytical Solution for Thermo-Electro-Elastic Problems of an Orthotropic Piezoelectric Hollow Cylinder Subjected to Various Loading
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作者 戴宏亮 王熙 戴庆华 《Journal of Shanghai Jiaotong university(Science)》 EI 2004年第4期34-40,共7页
An interpolation method was used to solve the Volterra integral equation of the second kind caused by interaction among thermal, electric and mechanical fields. The exact expressions for the transient responses of str... An interpolation method was used to solve the Volterra integral equation of the second kind caused by interaction among thermal, electric and mechanical fields. The exact expressions for the transient responses of stresses, electric displacement and electric potential in an orthotropic piezoelectric hollow cylinder were obtained by means of the finite integral transforms. From the sample numerical calculations, it is seen that the present method is suitable for an orthotropic piezoelectric hollow cylinder subjected to arbitrary thermal shock, mechanical load and transient electric excitation. The result can be used as a reference to solve other transient coupled problems of thermo-electro-elasticity. 展开更多
关键词 thermo-electro-elastic ORTHOTROPIC piezoelectric hollow cylinder transient
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Thermoelastoplastic Deformation Analysis of Electromechanical Equipments under Electrocaloric Shock
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作者 于建国 吕晨亮 叶庆泰 《Journal of Donghua University(English Edition)》 EI CAS 2006年第1期42-48,共7页
A coupled thermomechanical model is presented to investigate the thermoelastoplastic deformation mechanism of electromechanical equipments under the condition of electrocaloric shock. In the coupling model, differenti... A coupled thermomechanical model is presented to investigate the thermoelastoplastic deformation mechanism of electromechanical equipments under the condition of electrocaloric shock. In the coupling model, differentiating from the previous analyzing viewpoint that looked upon deformation work as additional heat source, temperature-field equation is established by considering the weakening role of deformation work on the intensity of internal heat source; in the process of setting up displacement-field equation, G-derivative of nonlinear functional is introduced into the traditional theory of elastoplastic finite deformation to simplify the expression of structural stiffness; stress-field equation is constructed by using the least square method to improve the stress solution obtained by constitutive equation. The presented model is converted into finite element program to simulate deforming process of 3-D structures with temperature-dependent material properties. As an example, thermal deformation analysis of Shanghai metro cars’ brake resistor is performed and compared with experimental results for illustrating the validity of the presented model. 展开更多
关键词 electromechanical equipments electro caloric shock thermomechanical coupling finite element analysis.
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Improved Ligand-Field Theoretical Calculations of R-Line Thermal Broadenings of MgO:Cr^(3+) and MgO:V^(2+)
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作者 ZHANG Zheng-Jie MA Dong-Ping 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第11期1245-1248,共4页
With the values of parameters obtained from improved ligand-field theory,by taking into account all theirreducible representations and their components in EPI as well as all the levels and the admixtures of basic wave... With the values of parameters obtained from improved ligand-field theory,by taking into account all theirreducible representations and their components in EPI as well as all the levels and the admixtures of basic wavefunc-tions within d^3 electronic configuration,the R-line thermal broadenings(TB)of both MgO:Cr^(3+)and MgO:V^(2+)havemicroscopic-theoretically been calculated.The results are in very good agreement with the experimental data.It is foundthat the R-line TB of MgO:Cr^(3+)or MgO:V^(2+)comes from the first-order term of EPI.The elastic Raman scattering ofacoustic phonons plays a dominant role in R-line TB of MgO:Cr^(3+)or MgO:V^(2+). 展开更多
关键词 improved ligand-field theory electron-phonon interaction R line thermal broadening elastic Raman scattering
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Structural, thermodynamics and elastic properties of Mg_(17)Al_(12), Al_2Y and Al_4Ba phases by first-principles calculations
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作者 黄志伟 赵宇辉 +3 位作者 侯华 赵宇宏 牛晓峰 韩培德 《Journal of Central South University》 SCIE EI CAS 2012年第6期1475-1481,共7页
Structural stabilities, thermodynamics stabilities, elastic properties and electronic structures of Mgl7Al12, Al2Y and AlaBa phases were analyzed by first-principles calculations with Castep and Drool3 program based o... Structural stabilities, thermodynamics stabilities, elastic properties and electronic structures of Mgl7Al12, Al2Y and AlaBa phases were analyzed by first-principles calculations with Castep and Drool3 program based on the density functional theory. The calculated results of heat of formation indicate that AI2Y phase has the strongest alloying ability. The calculated thermodynamic properties show that the thermal stability of these compounds gradually increases in the order ofMgl7Al12, A12Y and Al4Ba phases. Y or Ba addition to the Mg-Al alloys could improve the heat resistance. The calculated bulk modulus B, shear modulus G, elastic modulus E and Poisson ratio v show that the adding Y or Ba to Mg-Al alloys could promote the brittleness and stiffness, and reduce tenacity and plasticity by forming Al4Ba and Al2Y phases. The calculated cohesive energy and density of state (DOS) show that Al2Y has the strongest structural stability, then AlaBa and finally Mg17Al12. The calculated electronic structures show that Al2Y has the strongest structure stability because of the strong ionic bonds and covalent bonds combined action. 展开更多
关键词 Mg-Al alloys thermodynamics properties elastic properties electronic structure FIRST-PRINCIPLES
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Construction of deep-blue AIE luminogens with TPE and oxadiazole units 被引量:1
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作者 HUANG Jing CHEN PengYu +4 位作者 YANG Xiao TANG RunLi WANG Lei QIN JinQui LI Zhen 《Science China Chemistry》 SCIE EI CAS 2013年第9期1213-1220,共8页
In this paper, two AIE-active luminogens (Oxa-pTPE and Oxa-mTPE) constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal, optical and electronic properties were investig... In this paper, two AIE-active luminogens (Oxa-pTPE and Oxa-mTPE) constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal, optical and electronic properties were investigated. By linking TPE to the oxadiazole core through meta-or para-position, the intramolecular conjugation is effectively controlled. Thanks to the intelligent molecular design and specific AIE feature, when fabricated as emissive layers in non-doped OLEDs, they exhibit blue or deep-blue emission with CIE coordinates of (0.17, 0.23) and (0.15, 0.12), and good efficiencies with ηC, max and ηP, max up to 1.52 cd A-1 and 0.84 Im W-1 , shedding some light on the construction of deep-blue AIE fluorophores. 展开更多
关键词 aggregation-induced emission tetraphenylethene deep-blue emitter organic light-emitting diodes
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Thermoelastic coupling problems caused by thermal contact resistance:A discontinuous Galerkin finite element approach 被引量:2
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作者 ZHENG XiaoPing LIU DongHuan LIU YingHua 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第4期666-674,共9页
A discontinuous Galerkin (DG) finite element method is presented to solve the thermoelastic coupling problems caused by temperature and pressure dependent thermal contact resistance (TCR).The whole analysis is made up... A discontinuous Galerkin (DG) finite element method is presented to solve the thermoelastic coupling problems caused by temperature and pressure dependent thermal contact resistance (TCR).The whole analysis is made up of two parts,thermal and mechanical analysis.In thermal analysis,the DG method is employed to simulate the temperature jump phenomenon,which satisfies the imperfect thermal contact condition in a straightforward manner.In mechanical analysis,the impenetrability condition is fulfilled through a DG approach with penalty functions.The Picard iteration procedure with a relaxation technique is also adopted to accelerate the rate of convergence and avoid numerical instability.Numerical examples show that the present method is an attractive approach for solving thermoelastic coupling problems caused by TCR.The methodology can also be expanded to solve problems with friction finite deformation contact,node-to-segment contact and node-to-surface contact,etc.in a straightforward manner. 展开更多
关键词 thermoelastic coupling thermal contact resistance discontinuous Galerkin method penalty method relaxation technique
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