We investigate electronic properties of a hierarchical multilayer structure consisting of stacking of barriers and wells. The structure is formed in a sequence of generations, each of which is constructed with the sam...We investigate electronic properties of a hierarchical multilayer structure consisting of stacking of barriers and wells. The structure is formed in a sequence of generations, each of which is constructed with the same pattern but with the previous generation as the basic building blocks. We calculate the transmission spectrum which shows the multifractal behavior for systems with large generation index. From the analysis of the average resistivity and the multifractal structure of the wavefunctions, we show that there exist different types of states exhibiting extended, localized and intermediate characteristics. The degree of localization is sensitive to the variation of the structural parameters.Suggestion of the possible experimental realization is discussed.展开更多
Analytical models used to describe behaviour of steel frame loadbearing structures in fully developed fire usually do not allow for reduced joint stiffness due to increased member temperature. Joints previously design...Analytical models used to describe behaviour of steel frame loadbearing structures in fully developed fire usually do not allow for reduced joint stiffness due to increased member temperature. Joints previously designed as nominally rigid tend to become flexible in fire situation, with degree of flexibility increasing during fire development. Reliable analysis of this phenomenon and its influence on the redistribution of internal forces result in the need for developing appropriate characteristics, describing relationship between bending moment applied to the joint and joint rotation. Characteristics of such type, specified for fire conditions, depend on steel temperature, in the current work, the authors propose a practical approach to develop such characteristics, based on the knowledge of analogous characteristic prepared for persistent design situation. The developed technique does not require to generalize the classical component method to the case of fire, which may be difficult in practical situations. The proposed computational algorithm has been tested on an example of a typical beam-to-column joint.展开更多
The problems of best reconstruction of multivariate functions of the Riesz potential spaces from their values on a given mesh are considered, and the exact results of some classes of L_2(R^n) (and L_2(Q^n)) defined b...The problems of best reconstruction of multivariate functions of the Riesz potential spaces from their values on a given mesh are considered, and the exact results of some classes of L_2(R^n) (and L_2(Q^n)) defined by the Riesz potential are obtained.展开更多
文摘We investigate electronic properties of a hierarchical multilayer structure consisting of stacking of barriers and wells. The structure is formed in a sequence of generations, each of which is constructed with the same pattern but with the previous generation as the basic building blocks. We calculate the transmission spectrum which shows the multifractal behavior for systems with large generation index. From the analysis of the average resistivity and the multifractal structure of the wavefunctions, we show that there exist different types of states exhibiting extended, localized and intermediate characteristics. The degree of localization is sensitive to the variation of the structural parameters.Suggestion of the possible experimental realization is discussed.
文摘Analytical models used to describe behaviour of steel frame loadbearing structures in fully developed fire usually do not allow for reduced joint stiffness due to increased member temperature. Joints previously designed as nominally rigid tend to become flexible in fire situation, with degree of flexibility increasing during fire development. Reliable analysis of this phenomenon and its influence on the redistribution of internal forces result in the need for developing appropriate characteristics, describing relationship between bending moment applied to the joint and joint rotation. Characteristics of such type, specified for fire conditions, depend on steel temperature, in the current work, the authors propose a practical approach to develop such characteristics, based on the knowledge of analogous characteristic prepared for persistent design situation. The developed technique does not require to generalize the classical component method to the case of fire, which may be difficult in practical situations. The proposed computational algorithm has been tested on an example of a typical beam-to-column joint.
基金Supported by the National Natural Science Foundation of China !(19671012)by the Doctoral Programme Foundation of Institution
文摘The problems of best reconstruction of multivariate functions of the Riesz potential spaces from their values on a given mesh are considered, and the exact results of some classes of L_2(R^n) (and L_2(Q^n)) defined by the Riesz potential are obtained.
