Shape-controlled solvothermal synthesis of bismuth subcarbonate nanomaterials

Much effort has been devoted to the synthesis of novel nanostructured materials because of their unique properties and potential applications. Bismuth subcarbonate ((BiO)₂CO₃) is one of commonly used antibacterial agents against Helicobacter pylori (H. pylori). Different (BiO)₂CO₃ nanostructures such as cube-like nanoparticles, nanobars and nanoplates, were fabricated from bismuth nitrate via a simple solvothermal method. The nanostructures were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It was found that the solvents and precursors have an influence on the morphologies of (BiO)₂CO₃ nanostructures. The possible formation mechanism of different (BiO)₂CO₃ nanostructures fabricated under different conditions was also discussed.     

Conversion of carbohydrates into 5-hydroxymethylfurfural catalyzed by ZnCl2 in water

The incompletely coordinated zinc ions in the concentrated aqueous ZnCl(2) solution catalyze the direct conversion of carbohydrates into 5-hydroxymethylfurfural, and a moderate HMF yield up to 50% can be achieved.     

光孤子传输模型及其应用

从周期性集中放大系统孤子传输的基本方程出发，建立了比平均孤子模型适用范围更广、更精确的传输模型，运用微扰方法对孤子到达时间抖动作了研究，并与平均孤子模型给出的结果作了比较。     

分布式EDFA中受激喇曼散射对光孤子脉冲传输的影响

本文用数值方法研究了透明传输下,受激喇曼散射(SRS)对由分布式掺饵光纤放大器(d-EDFA)级联的传输线中传输的光孤子脉冲的泵功率、孤子脉冲平均功率演化、均方根脉宽谱宽积、孤子系统的能量辐射、以及对光孤子传输稳定性的影响.结果表明:SRS降低了系功率,减弱了孤子平均功率起伏,有利于光孤子传输,但也使孤子脉(谱)宽展宽,增大了孤子系统的能量辐射,对孤子传输稳定性产生不良的影响.     

A colorimetric chemosensor for fast detection of thiols based on intramolecular charge transfer

A TCNQ-based triphenylamine derivative (1) with strong intramolecular charge transfer (ICT) character was designed as a colorimetric sensor for thiols. Upon addition of thiols, the absorption spectrum of sensor 1 in aqueous solution was remarkably changed because the adduct of 1 with thiol decreased its ICT character. Sensor 1 showed highly selective and sensitive sensing ability toward thiols over other analytes. This selectivity could be easily observed by naked eyes, indicating that sensor 1 is a potential colorimetric sensor for thiols.     

Ignoring your neighbors: moment correlations dominated by indirect or distant interactions in an ordered nanomagnet array

We have studied the moment correlations within triangular lattice arrays of single-domain coaligned nanoscale ferromagnetic islands. Independent variation of lattice spacing along and perpendicular to the island axis tunes the magnetostatic interactions between islands through a broad range of relative strengths. For certain lattice parameters, the sign of the correlations between near-neighbor island moments is opposite to that favored by the pairwise interaction. This finding, supported by analysis of the total correlation in terms of direct and convoluted indirect contributions across multiple pairwise interactions, indicates that indirect interactions and/or those mediated by further neighbors can be tuned to be dominant, with implications for the wide range of systems composed of interacting nanomagnets.     

星型两亲性聚己内酯-b-聚甲基丙烯酸(2-羟乙酯)嵌段共聚物的合成和表征

通过开环聚合(ROP)和原子转移自由基聚合(ATRP)制备了一类新型的两亲性嵌段共聚物——六臂星形聚(ε-已内酯)-b-聚甲基丙烯酸(2-羟乙酯)(6sPCL-b-PHEMA).6sPCL-b-PHEMA通过三步反应合成:(1)双季戊四醇开环聚合ε-己内酯的合成6sPCL;(2)以2-溴异丁基酰溴封端星形聚合物制备大分...     

Classification of seven-point four-distance sets in the plane

A point set X in the plane is called a k-distance set if there are exactly k different distances between two distinct points in X. In this paper, we classify 7-point 4-distance sets and show that there are forty two 7-point 4-distance sets in the plane up to isomorphism, we also give some results about diameter graphs.     

基于离子液体氧化-萃取一步脱除二苯并噻吩的研究

以自制的硅胶表面担载树状钒配合物SG2.0-[VⅤO2-PAMAM-MSA]为催化剂,研究了离子液体耦合过氧化叔丁醇(TBHP)形成氧化-萃取体系一步脱除二苯并噻吩(DBT)的反应.研究结果表明,离子液体[Omim]PF6与氧化剂TBHP耦合使用时,在催化剂的催化作用下,DBT脱除率明显提高,且油品中的氧化产物二苯并噻吩亚砜(DBTO)和二苯并噻吩砜(DBTO2)迅速减少.当TBHP与DBT的摩尔比为3∶1,离子液体[Omim]PF6与模拟油的体积比为1∶3,温度90℃,反应时间60min时,DBT的脱除率可达95.0%.该氧化-萃取体系重复使用6次后,其性能没有明显降低.