On U(n)-invariant strongly convex complex Finsler metrics

Science China Mathematics - In this paper, we obtain a necessary and sufficient condition for a U(n)-invariant complex Finsler metric F on domains in ?n to be strongly convex, which also...     

Self-cleaning Anti-fouling TiO2/Poly(aryl ether sulfone) Composite Ultrafiltration Membranes

A series of novel TiO2/poly(aryl ether sulfone) ultrafiltration membranes with anti-fouling and self-cleaning properties was designed and prepared. First, anti-photocatalytic degraded fluorine contained polv(aryl ether sulfone) matrix(PAES-F) was synthesized. Then the composite membranes were prepared via TiO2 nanopartides and PAES-F polymer matrix by solution blending and non-solvent induced phase inversion methods. Further, separation efficiency, fouling behavior and self-cleaning property of the composite ultrafiltration(UF) membranes were investigated by dead-end filtration experiments using a polyacn lamide solution. The composite UF membranes exhibited outstanding self-cleaning efficiency and anti-photocatalytic degraded property after exposure to simulated sunliglit irradiation.The water flux recovery ratios(FRR)of the optimal composite UF membranes could reach 74.24%, which was attributable to photocatalytic degradation of the organic contaminant by TiO2. And the retention rates of the composite UF membranes could maintain over 97%, which indicated the excellent photocatalytic degradation resistance of the fluorine contained PAES-F matrix. The novel high perfomiance composite UF membranes have a broad application prospect in water treatment.     

速凝成晶-粘结法制备稀土磁致伸缩材料TbDyFe的研究

采用速凝成晶技术,制备了具有<112>和<110>择优取向的Tb0.27Dy0.73Fe1.95速凝片.研究发现,速凝片的择优取向和显微组织与冷却速度密切相关.随着冷却速度的增加,其择优取向从<112>向<110>变化,显微组织由枝状晶向胞枝晶转变.研究了由速凝片制备的稀土粘结磁致伸缩样品的性能.结果表明,当粉末粒度≤(100～150)μm时材料性能较好,具有<112择优取向的样品性能高于<110>择优取向的样品,磁场取向成型有利于材料性能的改善.获得了性能良好的粘结磁致伸缩材料,在238.8 kA·m-1时磁致伸缩系数达到740×10-6.     

Electrochemically deposited nanocomposite of chitosan and carbon nanotubes for detection of human chorionic gonadotrophin

A new label-free amperometric immunosensor was developed for detection of human chorionic gonadotrophin (hCG) based on multiwall carbon nanotubes-chitosan (MWNTs-CS) complex film and three-dimensional AuNPs-TiO(2) hybrid. Firstly, MWNTs-CS film was deposited on a glassy carbon electrode (GCE) by a simple and controllable electrodeposition method. Next, thionine (Thi), as a redox probe, was covalently bound onto the MWNTs-CS film with glutaraldehyde (GA) to obtain the Thi/MWNTs-CS film. The free amino groups of the composite membrane were used to adsorb AuNPs-TiO(2) for immobilizing human chorionic gonadotrophin antibody (anti-hCG) because of its large surface area and satisfactory biocompatibility. At last, BSA was employed to block possible remaining active sites. Under optimized conditions, the immunosensor displayed high sensitivity, good reproducibility, and a low detection limit of 0.08mIU/mL at 3 times the background noise. The ease of non-manual technique and the promising feature of biocomposite could serve as a versatile platform for constructing other biosensors.     

近中性条件下含铜多级孔氧化硅的合成及在苯酚羟基化反应中的催化性能

 在近中性条件下, 以正硅酸甲酯和 Cu(APTES)42+ (APTES: (EtO)3Si(CH2)3NH2) 为前驱体, P123 为模板剂, KCl 为添加剂合成了不同孔结构的含铜介孔氧化硅材料. 扫描电镜和氮气吸附结果表明, 当 Cu(APTES)42+/TMOS 摩尔比较高时能得到具有多级孔结构的材料. 在以 H2O2 为氧化剂的苯酚羟基化反应中, 具有多级孔结构的含铜介孔氧化硅材料表现出比单一介孔材料高的催化性能.     

Basic isoreticular metal–organic framework (IRMOF‐3) porous nanomaterial as a suitable and green catalyst for selective unsymmetrical Hantzsch coupling reaction

A catalytic amount of the basic metal–organic framework (IRMOF‐3) with organic substrates was found to be an efficient, selective and waste‐free green approach for the unsymmetrical Hantzsch coupling reaction. The catalyst can be isolated from the reaction mixture and reused at least four times. Copyright © 2014 John Wiley & Sons, Ltd.     

Existence and uniqueness of solutions for a fractional differential equation with multi-point boundary value problems

In this paper, we study the existence and uniqueness solutions of a fractional differential equation with multi-point boundary value problems. By using the fixed point theorems, some new results are established and two examples are given to demonstrate the application of main results.     

关于狭义相对论中"洛仑兹变换导出"的讲法的沿革

洛仑兹变换是狭义相对论中的一个关键问题，本文旨在对各种讲法作比较，从而求得对此问题有较全面深入的认识。