Electrical and optical properties of fluid iron from compressed to expanded regime

Using quantum molecular dynamics simulations, we show that the electrical and optical properties of fluid iron change drastically from compressed to expanded regime. The simulation results reproduce the main trends of the electrical resistivity along isochores and are found to be in good agreement with experimental data. The transition of expanded fluid iron into a nonmetallic state takes place close to the density at which the constant volume derivative of the electrical resistivity on internal energy becomes negative. The study of the optical conductivity, absorption coefficient, and Rosseland mean opacity shows that, quantum molecular dynamics combined with the Kubo-Greenwood formulation provides a powerful tool to calculate and benchmark the electrical and optical properties of iron from expanded fluid to warm dense region

A FUZZY COMPREHENSIVE EVALUATION OF ENTREPRENEUR BASED ON ABILITY CAPITAL

In this paper, the fuzzy mathematics method is applied to build a fuzzy comprehensive evaluation model of multilevel selection of entrepreneur ability capital. Fuzzy comprehensive evaluation is very effective in multiple factor decision-making and layered authorization is used in AHP to decide authority preferences. All these make the difference in subjective evaluation controlled to the minimum scope, hence the evaluating results are more objective and exact. The paper provides a scientific, practical and quantitative method for the system analysis and comprehensive evaluation of entrepreneur ability capital. Key words: entrepreneur ability capital, evaluation index system, fuzzy comprehensive evaluatio

Biharmonic Riemannian submersions from M2×RM^2\times R

In this paper, we study biharmonic Riemannian submersions $\pi:M^2\times\r\to (N^2,h)$ from a product manifold onto a surface and obtain some local characterizations of such biharmonic maps. Our results show that when the target surface is flat, a proper biharmonic Riemannian submersion $\pi:M^2\times\r\to (N^2,h)$ is locally a projection of a special twisted product, and when the target surface is non-flat, $\pi$ is locally a special map between two warped product spaces with a warping function that solves a single ODE. As a by-product, we also prove that there is a unique proper biharmonic Riemannian submersion H^2\times \r\to \r^2 given by the projection of a warped product

Biharmonic Riemannian submersions from a 3-dimensional BCV space

BCV spaces are a family of 3-dimensional Riemannian manifolds which include six of Thurston's eight geometries. In this paper, we give a complete classification of proper biharmonic Riemannian submersions from a 3-dimensional BCV space by proving that such biharmonic maps exist only in the cases of $H^2\times\mathbb{R}\to \mathbb{R}^2$ or $\widetilde{SL}(2,\mathbb{R})\to \mathbb{R}^2$. In each of these two cases, we are able to construct a family of infinitely many proper biharmonic Riemannian submersions. Our results on one hand, extend a previous result of the authors which gave a complete classification of proper biharmonic Riemannian submersions from a 3-dimensional space form, and on the other hand, can be viewed as the dual study of biharmonic surfaces (i.e., biharmonic isometric immersions) in a BCV space studied in some recent literature.Comment: 25 page