Solar Cell Design Using Metamaterials

Natural structure with simultaneous negative permittivity and permeability has not been discovered yet. However, using specially-designed metal embedded in dielectric bodies can achieve a kind of artificial negative index. This periodic structure which is smaller than the guided wavelength is known as a metamaterial. However, recent designs of metamaterials have some disadvantages when they are used in the application of solar cell. The perfect absorption is only within a narrow band, and for most of the solar spectrum, the absorption is no more than 10%. Here, a new kind of absorber for the solar spectrum has been designed and analyzed, in order to utilize the solar energy effectively

Full-Order Convergence of a Mixed Finite Element Method for Fourth-Order Elliptic Equations

AbstractBy using a special interpolation operator and an elaborate element analysis, in this paper, we improve the classical error estimates to full order for a mixed finite element method for the fourth-order elliptic equations on the rectangular mesh. Therefore we obtain the truly optimal error estimates in view of the interpolation space for the first time

Theoretical Modeling of Protective Oxide Layer Growth in Non-isothermal Lead Alloy Coolant Systems

The goal of the proposed research project is to provide basic understanding of the protective oxide layer behaviors and to develop oxide layer growth models of steels in non-isothermal lead-alloys (lead or lead-bismuth eutectic) coolant systems. Precise studies and simulations of all hydrodynamics with thermal conditions encountered in practical coolant loop systems by use of different flowing conditions in the laboratory are difficult and expensive, if not impossible. Therefore it is important and necessary to develop theoretical models to predict the protective oxide layer behaviors at the design stage of a practical lead-alloy coolant system, to properly interpret and apply experimental results from test loops, and to provide guidance for optimization in lead-alloy nuclear coolant systems. The research project, therefore, is aimed at understanding protective oxide layer growth and the optimal oxygen concentration level before lead-alloy nuclear coolants are ready for programmatic implementations and industrial applications

Theoretical Modeling of Protective Oxide Layer Growth in Non-isothermal Lead-Alloys Coolant Systems

The goal of the proposed research project is to provide basic understanding of the protective oxide layer behaviors and to develop oxide layer growth models of steels in non-isothermal leadalloys (lead or lead-bismuth eutectic) coolant systems. It is widely recognized that the corrosiveness of the lead-alloys is a critical obstacle and challenge for which it can be safely used or applied in the nuclear coolant systems. Active oxygen control technique can promote the formation of the “self-healing” oxide films on the structural material surface, drastically reducing steel corrosion and coolant contamination. Many experiments of steels exposed to flowing leadalloys have been carried out to study the protective oxide layer behaviors. However, the experimental data are still very incomplete at present and can not provide the dependence of the oxide behaviors on the system operating temperature, temperature profiles along the lead-alloys loop, oxygen concentration, flow velocity, etc. In addition, oxygen distribution in a nonisothermal lead-alloys coolant system is not well understood. Precise studies and simulations of all hydrodynamics with thermal conditions encountered in practical coolant loop systems by use of different flowing conditions in the laboratory are difficult and expensive, if not impossible. Therefore it is important and necessary to develop theoretical models to predict the protective oxide layer behaviors at the design stage of a practical lead-alloys coolant system, to properly interpret and apply experimental results from test loops, and to provide guidance for optimization in lead-alloys nuclear coolant systems. The research project, therefore, is aimed at filling the gaps of protective oxide layer growth and the oxygen concentration level before lead-alloys nuclear coolant is ready for programmatic implementations and industrial applications

A NEW METHOD FOR MEASURING SEGMENT MASS & SEGMENT CENTER OF MASS LOCATION OF HUMAN BODY

The purpose of this study was to introduce a new method for measuring segment mass & segment center of mass of human body, and determine whether valid measures of segment inertial properties can be generated from using this new method. In first place, we introduced the principles of two types of instruments used in this new method, one for measuring segment moment of mass (mb x rb), and the other for measuring segment center of mass (rb), and then we obtained segment mass (mb)' We measured 9 subjects using the above two types of instruments, and these segments measured included one forearm-hand, one upper limb, one shank-foot and one lower limb. There is no significance discrepancy between the calculations of database provided by Xiuyuan Zheng using eT method and ours, which showed that the new method is a valid method

A Digital Watermarking Approach Based on DCT Domain Combining QR Code and Chaotic Theory

This paper proposes a robust watermarking approach based on Discrete Cosine Transform domain that combines Quick Response Code and chaotic system.Comment: 7 pages, 6 figure

Parabolic frequency monotonicity for two nonlinear equations under Ricci flow

In this paper, we consider the parabolic frequency for positive solutions of two nonlinear parabolic equations under the Ricci flow on closed manifolds. We obtain the monotonicity of parabolic frequency for the solution of two nonlinear parabolic equations with bounded Ricci curvature, then we apply the parabolic frequency monotonicity to get some integral type Harnack inequalities and we use -K1 instead of the lower bound 0 of Ricci curvature from Theorem 4.3 in 16, where K1 is any positive constant.Comment: 15 pages. arXiv admin note: substantial text overlap with arXiv:2310.0518

Two New Finite Element Schemes and Their Analysis for Modeling of Wave Propagation in Graphene

© 2020 The Author(s) In this paper, we investigate a system of governing equations for modeling wave propagation in graphene. Compared to our previous work (Yang et al., 2020), here we re-investigate the governing equations by eliminating two auxiliary unknowns from the original model. A totally new stability for the model is established for the first time. Since the finite element scheme proposed in Yang et al. (2020) is only first order in time, here we propose two new schemes with second order convergence in time for the simplified modeling equations. Discrete stabilities inheriting exactly the same form as the continuous stability are proved for both schemes. Convergence error estimates are also established for both schemes. Numerical results are presented to justify our theoretical analysis