On regularity criterion to the 3D axisymmetric incompressible MHD equations

This paper is concerned with the regularity criterion for a class of axisymmetric solutions to 3D incompressible magnetohydrodynamic equations. More precisely, for the solutions that have the form of u = u_re_r+u_θe_θ+u_ze_z and b = b_θe_θ, we prove that if |ru(x,t)|≤C holds for ?1≤t < 0, then (u,b) is regular at time zero. This result can be thought as a generalization of recent results in for the 3D incompressible Navier‐Stokes equations. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis,Structure and Catalytic Properties of a Cu(II) Coordination Polymer Constructed from Paddle-Wheel Building Blocks

A novel dinuclear Cu(II) coordination polymer, [Cu(BCPPO)H₂O]_n (1) [H₂BCPPO = bis -4-carboxyphenyl phenyl phosphine oxide], has been synthesized and structurally characterized by single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, elemental analysis and infrared spectroscopy. As revealed by the single crystal X-ray diffraction, in complex 1, two paddle-wheel-type Cu₂ units were connected by two BCPPO ligands to form one-dimensional infinite chain. The A³ coupling reaction of phenylacetylene, aldehyde and amine (piperidine) in the presence of the dinuclear Cu(II) coordination polymer as an efficient heterogeneous catalyst has also been studied. Complex 1 displayed high activity and afforded the corresponding propargylamines with moderate yields.     

Stationary oscillation for chaotic shunting inhibitory cellular neural networks with impulses

In this paper, we study stationary oscillation for general shunting inhibitory cellular neural networks with impulses which are complex nonlinear neural networks. In a recent paper [Z. J. Gui and W. G. Ge, Chaos 16, 033116 (2006)], the authors claimed that they obtained a criterion of existence, uniqueness, and global exponential stability of periodic solution (i.e., stationary oscillation) for shunting inhibitory cellular neural networks with impulses. We point out in this paper that the main result of their paper is incorrect, and presents a sufficient condition of ensuring existence, uniqueness, and global stability of periodic solution for general shunting inhibitory cellular neural networks with impulses. The result is derived by using a new method which is different from those of previous literature. An illustrative example is given to demonstrate the effectiveness.     

微量元素硒对眼科疾病防治的研究进展

硒是人体必需微量营养元素,在人体代谢过程中参与多种代谢活动,参与维持眼睛正常的生理生化功能,微量元素硒缺乏会引起眼睛的生理生化功能紊乱,引起眼科疾病如老年性白内障等,适当补硒可以激活体液和细胞免疫调节能力.参考相关文献综述了硒的作用机制及其对眼科疾病防治的进展.     

Investigation of magnetostrictive/piezoelectric multilayer composite with a giant zero-biased magnetoelectric effect

In this paper, we investigate the resonance magnetoelectric (ME) effect in the middle supported multilayer composites consisting of high-permeability Fe-based nanocrystalline soft magnetic alloy Fe_73.5Cu₁Nb₃Si_13.5B₉ (FeCuNbSiB), Nickel (Ni), and piezoelectric Pb(Zr_1?x Ti _x )O₃ (PZT). The coupling effect between positive magnetostrictive FeCuNbSiB and negative magnetostrictive Ni results in the build-in magnetic bias due to their different magnetic permeability and coercivity. As a result, a giant resonance ME voltage coefficient (α _ME,r ) at zero DC magnetic bias field (H _dc) and multi-peaks of α _ME,r for FeCuNbSiB/Ni/PZT/Ni/FeCuNbSiB composite are observed. The experimental results show that the giant zero-biased α _ME,r strongly depends on the thickness of FeCuNbSiB ribbon. The maximum zero-biased α _ME,r is up to 86 V/cm?Oe for FeCuNbSiB/Ni/PZT/Ni/FeCuNbSiB with four-layer FeCuNbSiB ribbons, which is ～500 times higher than that of the previously reported NKNLS-NZF/Ni/NKNLS-NZF trilayer composite. Compared with the peak α _ME,r and the optimum H _dc of Ni/PZT/Ni composite, the largest peak α _ME,r of FeCuNbSiB/Ni/PZT/Ni/FeCuNbSiB composite with four-layer FeCuNbSiB ribbons increases ～185 %, and the optimum H _dc decreases ～300 Oe, respectively. Based on the nonlinear magnetostrictive constitutive relation and the magnetoelectric equivalent circuit, a theoretical model of α _ME,r versus H _dc is built under free boundary conditions. Calculated zero-biased α _ME,r and α _ME,r versus H _dc are in good agreement with the experimental data. This laminate composite shows promising applications for high-sensitivity power-free magnetic field sensors, zero-biased ME transducers and small-size energy harvesters.     

标准状态下氮气在0.145～2.058μm的色散特性

为了研究氮气在宽光谱范围内的色散特性,基于气体色散理论,在标准条件下(温度为293.15K,气压为101325Pa),利用二阶Sellmeier公式和最小二乘法拟合得到氮气在0.145～2.058μm波长范围内的色散公式。该公式在全波段范围内的不确定度约为2.1×10-7,与原始测量数据的准确度一致。与现有色散公式相比,该公式的适用波长范围更宽,可提供氮气在0.27～0.47μm波段更多的折射率信息,具有较广泛的适用性。通过实验测量氮气在633nm处的折射率验证了该公式的有效性。     

Altering synchronizability by adding and deleting edges for scale-free networks

In this paper we propose two methods for altering the synchronizability of scale-free networks: (1) adding edges between the max-degree nodes and min-degree nodes; (2) deleting edges between the max-degree nodes and max-degree nodes. After adding and deleting edges, we find that the former, adding process can weaken synchronizability, while the latter, deleting process can enhance it; the two processes (adding and deleting) can preserve the scale-free structure; the study of the average clustering coefficient indicates that it is not the most closely correlated with the synchronizability among the topological features considered. Our work also suggests that there are some essential relations between the network synchronization and the dynamics of economic systems. They can be used to deal with some problems in the real world, such as relieving the economic crisis. In addition, the adding and deleting processes may have potential applications in modifying network structure, in view of their low cost.     

蛋白质巯基亚硝基化分子机制及其疾病相关性

蛋白质翻译后修饰对蛋白质生物学功能起着至关重要的作用.蛋白质巯基亚硝基化(S-nitrosylation,SNO)是一种一氧化氮相关的氧化还原型可逆修饰.它广泛存在于动物、植物和微生物中.近年来的研究表明SNO与蛋白质修饰位点的精细化学结构紧密关联,其中可能存在多种尚未证实的中间体.另一方面,研究发现SNO与肿瘤、炎症、衰老、阿尔茨海默症和帕金森综合症等许多重大疾病相关.为了进一步药物发现与疾病治疗研究的需要,本文对SNO的形成机理与研究现状进行了系统总结,并着重介绍了SNO与相关疾病的研究进展.     

Performance of dye-sensitized solar cells based on natural dyes

The natural dyes were successfully extracted from spinach, pitaya pericarp, orange peel, ginkgo leaf, purple cabbage and carrot, and then fabricated a dye-sensitized solar cells (DSSCs). It suggested that the absorption properties of natural dyes were strongly dependent on the types and concentration of pigments, and the purple cabbage exhibited an obvious absorption at 317 nm. Meanwhile, a higher conversion efficiency of 0.157% was obtained as the DSSCs were prepared by using purple cabbage, but the DSSCs showed a poor performance when the carrot was used as natural dyes, just achieved 0.01%. FTIR spectra revealed that purple cabbage showed a better adsorption properties between TiO₂ films and dyes than carrot. The dipping time was further investigated and proved that an optimal dipping time was 6 min, the DSSCs using purple cabbage could achieve 0.146% in photoelectric conversion efficiency.     

Impulsive control of time-delay systems using delayed impulse and its application to impulsive master-slave synchronization

This Letter is concerned with impulsive control of a class of nonlinear time-delay systems. Some uniform stability criteria for the closed-loop time-delay system under delayed impulsive control are derived by using piecewise Lyapunov functions. Then the criteria are applied to impulsive master-slave synchronization of some secure communication systems with transmission delays and sample delays under delayed impulsive control. Two numerical examples are given to illustrate the effectiveness of the derived results.