Flexoelectric-induced voltage shift in a weak anchoring hybrid aligned nematic fiquid crystai cell is investigated theoretically. Based on the elastic theory of liquid crystal and the variation method, the equations f...Flexoelectric-induced voltage shift in a weak anchoring hybrid aligned nematic fiquid crystai cell is investigated theoretically. Based on the elastic theory of liquid crystal and the variation method, the equations for the bulk and the boundary of the cell are derived. By computer simulation, the dependence of the shift voltage on the sum of the ttexoelectric coefficients and the anchoring energy strength is obtained. As a result, a novel method to determine the sum of the flexoelectric coefficients by measuring the shift voltage is put forward.展开更多
We have investigated the structural and elastic properties of MgB2 under high pressures using the full- potential linearized muffin-tin orbital (FP-LMTO) scheme within the generalized gradient approximation correcti...We have investigated the structural and elastic properties of MgB2 under high pressures using the full- potential linearized muffin-tin orbital (FP-LMTO) scheme within the generalized gradient approximation correction (GGA) in the frame of density functional theory. The calculated pressure dependence of the normalized volume is in excellent agreement with the experimental results. At the same time the elastic constants and acoustic anisotropy as a function of applied pressure are presented. Through the quasi-harmonic Debye model, we also investigate the thermodynamic properties of MgB2.展开更多
The elastic properties of the wurtzite-type aluminum nitride (w-AlN) are investigated by ab initio plane-wave pseudopotential density functional theory method. The pressure dependences of the normalized primitive ce...The elastic properties of the wurtzite-type aluminum nitride (w-AlN) are investigated by ab initio plane-wave pseudopotential density functional theory method. The pressure dependences of the normalized primitive cell volume V/Vo, the elastic constants cij, the aggregate elastic modulus (B, G, E), the Poisson's ratio (v), and the Debye temperature θD are successfully obtained. From the elastic constants of the w-AlN under pressure, we find that the w-AlN should be unstable at higher pressure than 61.33 GPa.展开更多
基金Supported by the Natural Science Foundation of Hebei Province under Grant No. A2010000004the National Natural Science Foundation of China under Grant No. 60736042+1 种基金the Key Subject Construction Project of Hebei Province Universitythe Research Project of Hebei Education Department under Grant No. Z2011133
文摘Flexoelectric-induced voltage shift in a weak anchoring hybrid aligned nematic fiquid crystai cell is investigated theoretically. Based on the elastic theory of liquid crystal and the variation method, the equations for the bulk and the boundary of the cell are derived. By computer simulation, the dependence of the shift voltage on the sum of the ttexoelectric coefficients and the anchoring energy strength is obtained. As a result, a novel method to determine the sum of the flexoelectric coefficients by measuring the shift voltage is put forward.
基金The project supported by National Natural Science Foundation of China under Grant No. 60436010 and the Scientific Research Foundation for Returned 0verseas Chinese Scholars of the Ministry of Education under Grant No. 2004176-6-4
文摘We have investigated the structural and elastic properties of MgB2 under high pressures using the full- potential linearized muffin-tin orbital (FP-LMTO) scheme within the generalized gradient approximation correction (GGA) in the frame of density functional theory. The calculated pressure dependence of the normalized volume is in excellent agreement with the experimental results. At the same time the elastic constants and acoustic anisotropy as a function of applied pressure are presented. Through the quasi-harmonic Debye model, we also investigate the thermodynamic properties of MgB2.
基金National Natural Science Foundation of China under Grant Nos.10576020 and 10776022
文摘The elastic properties of the wurtzite-type aluminum nitride (w-AlN) are investigated by ab initio plane-wave pseudopotential density functional theory method. The pressure dependences of the normalized primitive cell volume V/Vo, the elastic constants cij, the aggregate elastic modulus (B, G, E), the Poisson's ratio (v), and the Debye temperature θD are successfully obtained. From the elastic constants of the w-AlN under pressure, we find that the w-AlN should be unstable at higher pressure than 61.33 GPa.