An exact-designed mesh shape with favorable surface accuracy is of practical significance to the performance of large cable-network antenna reflectors. In this study, a novel design approach that could guide the gener...An exact-designed mesh shape with favorable surface accuracy is of practical significance to the performance of large cable-network antenna reflectors. In this study, a novel design approach that could guide the generation of exact spatial parabolic mesh configurations of such reflector was proposed. By incorporating the traditional force density method with the standard finite element method, this proposed approach had taken the deformation effects of flexible ring truss supports into consideration, and searched for the desired mesh shapes that can satisfy the requirement that all the free nodes are exactly located on the objective paraboloid. Compared with the conventional design method,a remarkable improvement of surface accuracy in the obtained mesh shapes had been demonstrated by numerical examples. The present work would provide a helpful technical reference for the mesh shape design of such cable-network antenna reflector in engineering practice.展开更多
The electronic structures, deformation charge density, dipole moment, and optical properties of N-La-codoped anatase titanium dioxide （TiO2） are studied using the plane-wave ultrasoft pseudopotential method based on...The electronic structures, deformation charge density, dipole moment, and optical properties of N-La-codoped anatase titanium dioxide （TiO2） are studied using the plane-wave ultrasoft pseudopotential method based on the density functional theory （DFT）. The optical properties of two-ion-doped TiO2 are analyzed via electronic structures, deformation charge density, and dipole moment. For the model of N-La-doped TiO2, a smaller atom fraction of N and La atoms induces better optical properties. The absorption edges of two doped TiO2 models redshift to the visible-light region.展开更多
文摘An exact-designed mesh shape with favorable surface accuracy is of practical significance to the performance of large cable-network antenna reflectors. In this study, a novel design approach that could guide the generation of exact spatial parabolic mesh configurations of such reflector was proposed. By incorporating the traditional force density method with the standard finite element method, this proposed approach had taken the deformation effects of flexible ring truss supports into consideration, and searched for the desired mesh shapes that can satisfy the requirement that all the free nodes are exactly located on the objective paraboloid. Compared with the conventional design method,a remarkable improvement of surface accuracy in the obtained mesh shapes had been demonstrated by numerical examples. The present work would provide a helpful technical reference for the mesh shape design of such cable-network antenna reflector in engineering practice.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50873047)
文摘The electronic structures, deformation charge density, dipole moment, and optical properties of N-La-codoped anatase titanium dioxide （TiO2） are studied using the plane-wave ultrasoft pseudopotential method based on the density functional theory （DFT）. The optical properties of two-ion-doped TiO2 are analyzed via electronic structures, deformation charge density, and dipole moment. For the model of N-La-doped TiO2, a smaller atom fraction of N and La atoms induces better optical properties. The absorption edges of two doped TiO2 models redshift to the visible-light region.
