高分子载体手性催化剂在不对称碳碳键形成中的应用

根据反应类型,综述了近年新发现的用于不对称碳碳键形成中的具有较好催化活性和立体选择性的高分子载体手性催化剂及制备方法.     

Cellulosic value-added products from sugarcane bagasse

Cellulose - Sugarcane bagasse (SCB) is a major by-product of the sugarcane industry and one of the most common renewable and sustainable cellulosic materials for various industrial...     

TiO2/activated carbon fibers photocatalyst: Effects of coating procedures on the microstructure, adhesion property, and photocatalytic ability

In order to more easily separate TiO₂ photocatalyst from the treated wastewater, TiO₂ film was immobilized on the surface of activated carbon fibers (ACFs) by employing two kinds of coating procedures, dip-coating, and hydrothermal treatment. The effects of coating procedures on microstructure of TiO₂-coated ACFs (TiO₂/ACFs), such as morphology, porous property, crystal structure, and light absorption characteristics were investigated in detail. The adhesion property between TiO₂ film and ACFs was evaluated by ultrasonic vibration, and the photocatalytic activity of TiO₂/ACFs was tested by the photocatalytic decoloration of methylene blue solution. The results show that hydrothermal treatment presented many advantages to obtain high-performance TiO₂/ACFs photocatalyst in comparison with dip-coating. Hydrothermal treatment could improve the binding property between TiO₂ films and ACFs, which endowed the as-obtained TiO₂/ACFs photocatalyst with improved reusable performance, and TiO₂/ACFs synthesized by hydrothermal treatment presented higher photocatalytic activity.     

Hopf bifurcation analysis in a fluid flow model of Internet congestion control algorithm

This paper focuses on the Hopf bifurcation analysis of some classes of nonlinear time-delay models, namely fluid flow models, for the Internet congestion control algorithm of TCP/AQM networks. Using tools from control and bifurcation theory, it is proved that there exists a critical value of communication delay for the stability of the network. When the delay passes through the critical value, the system loses its stability and a Hopf bifurcation occurs. Furthermore, the stability of the bifurcation and direction of the bifurcating periodic solutions are determined by applying the normal form theory and the center manifold theorem. Finally, some numerical examples are given to verify the theoretical analysis.     

Strong anisotropy barriers of two theoretically modeled cyano-bridged magnets [(PY5Me2)4M4Re(CN)7] (M = V, Ni): DFT predictions

On the basis of the experimentally synthesized [(PY5Me₂)₄Mn₄Re(CN)₇]⁵⁺, the theoretically modeled clusters of [(PY5Me₂)₄V₄Re(CN)₇]⁵⁺ and [(PY5Me₂)₄Ni₄Re(CN)₇]⁵⁺ both have strong magnetic anisotropy energy barriers.