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Using plane-wave ultrasoft pseudopotential method based on first-principles density functional theory (DFT), the adsorption of Cs atom on As-rich GaAs(001) β 2 (2 × 4) reconstruction phase and Ga-rich GaAs(001)(4 × 2) reconstruction phase are investigated. The adsorption energy, work function, dipole moment, ionicity, band structure and density of state (DOS) of Cs adsorbed GaAs β 2 (2 × 4) and (4 × 2) models are calculated. The stability and electronic structure of Cs adsorbed GaAs β 2 (2 × 4) and (4 × 2) models are compared. Result shows that β 2 (2 × 4) phase is stable than the (4 × 2) phase and after that Cs adsorption β 2 (2 × 4) phase is more beneficial for photoemission. [ABSTRACT FROM AUTHOR]

In this paper, we develop and analyze a discontinuous Galerkin (DG) method for the two-dimensional nonlinear Zakharov-Kuznetsov (ZK) equation. The DG method could be applied without introducing any auxiliary variables or rewriting the original equation into a larger system. Stability and an error estimate are discussed carefully. Finally, a numerical example for the nonlinear problem is given to show that the scheme attains the optimal $(k+1)$th order of accuracy for piecewise $Q^{k}$ polynomials of degree k when $k\geq2$. [ABSTRACT FROM AUTHOR]

Does the supply of shares affect stock price? It is an important problem not only for investors but also for the financial regulators. Stock supply could affect stock price only when there was a downward-sloping demand curves theoretically. Therefore, an empirical test on the elasticity of stock demand curves is necessary. Based on the institutional bidding data in detail during period of IPO book building, our research shows that demand curve is downward-sloping both on primary market and secondary market, which means that supply of shares will have an effect on the stock price. Therefore, the supply and demand of shares should be taken into account when financial regulators making policies and investors making investment decisions. [ABSTRACT FROM AUTHOR]

Abstract: This paper addresses the robust finite-time control problem for a family of uncertain discrete-time Markovian jump systems with time delay. Initially, the concepts of stochastic finite-time boundedness and stochastic finite-time stabilization are given. Then, a stochastic finite-time controller is designed such that the underlying closed-loop discrete jump time-delay system is stochastic finite-time boundedness and satisfies a prescribed performance level in some given finite-time interval. Based on Lyapunov approach, sufficient criteria on the stochastic finite-time stabilization are established for the solvability of the problem, which can be handled by a feasibility problem in the form of linear matrix inequalities with a fixed parameter. Finally, simulation examples are presented to demonstrate the validity of the developed techniques. [Copyright &y& Elsevier]

FeCl3-catalyzed aza-Diels-Alder reaction of methylenecyclopropane with imine provides a facile and efficient route for the synthesis of tetrahydroquinoline with a spirocyclopropyl ring. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a four-parameter quadrilateral nonconforming finite element with double set parameter (DSP) is presented. The element is originated from the nonconforming rotated element and bilinear element, thus we can call it element. We prove that it is an anisotropic and superconvergent nonconforming quadrilateral finite element. The results of this paper can be regarded as extensions of the DSP method to the second order problems, which show some new merits of it. Finally, numerical results are presented, which coincides with our theoretical analysis. [Copyright &y& Elsevier]

Abstract This study demonstrates an isotropic flexible absorptive metamaterial structure for terahertz wave bands based on topological-optimization design. One rotationally symmetric absorbing element consists of a polarization-sensitive metamaterial cell arranged with a counterclockwise topology. A flexible topological metamaterial absorber is formed from crystalline elements through an infinite periodic arrangement using Floquet's theorem. This artificial material achieves dual-frequency absorption with peak absorptions of 94% and 99.9% at 0.136 and 0.143 THz, respectively. The independent polarization angle of the two absorption peaks exceeds 45°under an oblique incident-wave process operation and in bending measurement, which indicate polarization isotropy. The equivalent electrical thickness corresponding to the minimum resonance point is close to one-ninth. The proposed ultra-thin flexible artificial material not only possesses perfect conformity with complex surfaces but also achieves larger angle electromagnetic absorption. The study results can present this material a potential candidate for polarized manipulation in electromagnetic stealth and electromagnetic control in the terahertz technology. [ABSTRACT FROM AUTHOR]

Researchers are showing an increasing interest in high-performance flexible pressure sensors owing to their potential uses in wearable electronics, bionic skin, and human–machine interactions, etc. However, the vast majority of these flexible pressure sensors require extensive nano-architectural design, which both complicates their manufacturing and is time-consuming. Thus, a low-cost technology which can be applied on a large scale is highly desirable for the manufacture of flexible pressure-sensitive materials that have a high sensitivity over a wide range of pressures. This work is based on the use of a three-dimensional elastic porous carbon nanotubes (CNTs) sponge as the conductive layer to fabricate a novel flexible piezoresistive sensor. The synthesis of a CNTs sponge was achieved by chemical vapor deposition, the basic underlying principle governing the sensing behavior of the CNTs sponge-based pressure sensor and was illustrated by employing in situ scanning electron microscopy. The CNTs sponge-based sensor has a quick response time of ~105 ms, a high sensitivity extending across a broad pressure range (less than 10 kPa for 809 kPa−1) and possesses an outstanding permanence over 4000 cycles. Furthermore, a 16-pixel wireless sensor system was designed and a series of applications have been demonstrated. Its potential applications in the visualizing pressure distribution and an example of human–machine communication were also demonstrated. [ABSTRACT FROM AUTHOR]