Electrocatalysis for the hydrogen peroxide and nitrite at carbon paste electrode modified with a new zinc complex of 1-pentyl-1H-benzo[d][1,2,3]triazole

A conductive carbon paste electrode (CPE) comprising a new zinc complex of [Zn(C₁₁H₁₅N₃)₂Cl₂] and carbon powder was fabricated by the direct mixing method. The structure of [Zn(C₁₁H₁₅N₃)₂Cl₂] was characterized by X-ray crystallography and elemental analysis. The electrochemical behavior and electrocatalysis of the new zinc complex modified CPE (Zn–CPE) have been studied in detail. This bulk-modified Zn–CPE displayed good electrocatalytic activity toward the reduction of the hydrogen peroxide and nitrite. The results are reproducible with a lower detection limit than reported currently using other modified electrodes. Also, this bulk-modified CPE exhibits remarkable long-term stability, simple preparation, and inexpensive material, which is important for practical application on electrochemistry sensors.     

Distinct magnetic properties of one novel type of nanoscale cobalt-iron Prussian blue analogues synthesized in microemulsion

One novel type of nanoscale cobalt-iron Prussian blue analogues (PBA) in the form of mixed nanorods and nanocubes were synthesized using cetyltrimethyl ammonium bromide (CTAB) as the surfactant in microemulsion at low temperature. The generated products were characterized by SQUID, XRD and IR techniques, etc. The effects of potassium contents, cobalt-to-iron ratios, reaction temperatures on the properties of the nanoscale cobalt-iron PBA were systematically explored. The results showed that the novel type of nanomaterials possessed distinct magnetic properties in that their coercivities were intensely dependent on cobalt-to-iron ratios and potassium contents. Furthermore, it was observed that low reaction temperature not only affected the morphologies of the products, but also had influence on their magnetic properties. Additionally, the cobalt-iron Prussian blue analogues were strongly influenced by CTAB around their surface, which led to higher Curie temperatures.     

光镊系统的组建及光阱效应的观察

光镊是美国科学家Arthur Ashkin于1986年发明的,现被用来操控微小粒子和作为微小力的传感器.随着光镊技术的不断发展,光镊在生物大分子的操控和生物大分子生命过程中动力学研究方面发挥着巨大作用.本文介绍了光镊的工作原理,以及如何利用实验室现有条件,以较低成本搭建了一个简化的光镊系统,并观察了光镊对几种微小粒子的捕捉情况,证实了光阱有一定的作用范围,且其捕获能力随微粒尺寸增大而减小.     

新奇纳米结构SiOx的自组织生长及其发光

采用化学气相沉积法,以纳米Mg2Si和SiO2的混合粉体作为硅源,在较低温度自组织生长了大量绳状SiOx新奇纳米结构。利用扫描电子显微镜、透射电子显微镜等手段对纳米结构进行了系统表征,并在室温观测到了光致发光,其发光峰峰位在560nm附近,在此基础上对该纳米结构的生长机理进行了深入的讨论。     

Hodge Integrals and Integrable Hierarchies

We show that the generating series of some Hodge integrals involving one or two partitions are τ-functions of the KP hierarchy or the 2-Toda hierarchy, respectively. We also reformulate the results as a relationship between the relative invariants of some local Calabi-Yau geometries and integrable hierarchies and present some more examples using the topological vertex.     

一种改进型的Y 环双频带通FSS

针对传统的Y环分形双频FSS容易出现栅瓣的缺点,设计了一种改进型的Y环双频带通FSS。仿真分析了该FSS对不同入射角度以及不同极化方式入射波的频率响应特性;考虑到该结构具有若干几何参数,仿真并分析了各几何参数对FSS频率响应特性的影响。仿真结果表明该结构可实现Ku波段Ka波段双频工作,可有效消除栅瓣,并且具有较好的稳定性。在航空航天领域以及多频段卫星通讯领域有很大的工程实用价值。     

A new titanium (IV) complex bearing phenoxyimine‐fluorene ligand and its use as catalyst for ethylene homo‐ and copolymerization

A new titanium (IV) complex bearing phenoxyimine‐fluorene ligand was prepared and its behaviors in ethylene homo‐ and copolymerization with 1‐hexene, 1‐octene, and norbornene in the presence of modified methylaluminoxane (MMAO) were studied respectively. The effects of various polymerization conditions including polymerization temperature, ethylene pressure and the concentration of comonomer on the catalytic activities and properties of the resultant polymer were investigated. The broad molecular weight distribution of resulting polymer indicated that the multiple active species were formed during polymerization. Such complex showed good catalytic activities in ethylene homo‐ and copolymerizations and good capabilities of incorporating various comonomers into polyethylene backbone. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1617–1621, 2010     

Synthesis of SnO_2 nanorods from aqueous solution:The effect of preparation conditions on the formed patterns

<正>SnO_2 nanorods were deposited on the Si substrates in an aqueous solution containing both SnCl_4 and CO(NH_2)_2.It is found that different self-assembled patterns of SnO_2 nanorods can be obtained by changing the deposition conditions such as the molar ratio of CO(NH_2)_2 to SnCl_4 and the pretreatment of the substrate.Scattered SnO_2 nanorods,for example,can be changed into flower-like patterns when the molar ratio of CO(NH_2)_2 to SnCl_4 is raised,and well-aligned nanorod arrays can be formed when the pretreatment of the substrate is changed.In addition,some interesting patterns,e.g.tree-like patterns,can also be observed.     

New Coumarins and Triterpenes from Calophyllum inophyllum

Four new coumarins, 1 – 4 , and two new triterpenes, 5 and 6 , along with nine known compounds have been identified from the leaves of Calophyllum inophyllum on the basis of spectroscopic analyses and chemical methods. The structure of apetalolide ( 7 ), previously reported from C. apetalum, was revised by means of 2D‐NMR, and the absolute configuration of the known compound inophyllum D ( 8 ) was established by a modified Mosher's method.     

Chemoselective and enantioselective transfer hydrogenation of β,β-disubstituted nitroalkenes catalyzed by a water-insoluble chiral diamine–rhodium complex in water

Asymmetric transfer hydrogenation of β,β-disubstituted nitroalkenes catalyzed by a chiral diamine–rhodium complex in combination with HCO₂Na–HCO₂H as a hydrogen source in water was successfully realized with high reactivity, excellent chemoselectivity and good enantioselectivity. The metal precursor and pH value of the aqueous solution have a large influence on the reactivity and chemoselectivity. The substituents on the benzene rings and the sulfonyl groups of TsDPEN have significant effects on the enantioselectivity. This catalytic asymmetric transformation is one of the most practical pathways to obtain optically active nitroalkanes.