Large-scale synthesis and microstructure of SnO2 nanowires coated with quantum-sized ZnO nanocrystals on a mesh substrate

Large-quantity single-crystal SnO(2) nanowires coated with quantum-sized ZnO nanocrystals (nc-ZnO/SnO(2) nanowires) were directly synthesized by thermal evaporation of SnO powder and a mixture of basic ZnCO(3) and graphite powders. A common stainless steel mesh was used to collect the products. The microstructure and possible growth mechanism of the nc-ZnO/SnO(2) nanowires were investigated. Results showed that tetragonal structured SnO(2) nanowires were obtained, whose surfaces were coated with single-layer ZnO nanocrystals with an average diameter of less than 5 nm. The nanowires had cross-rectangle section with width-to-thickness aspect ratio ranging from 2:1 to 5:1. The lengths of the nanowires were several tens of micrometers. ZnO nanocrystals were single crystalline wurtzite structures, which coated the whole nanowires and distributed uniformly. The possible growth mechanism of the composite nanowires may be enucleated that Zn atoms in the source vapor will replace the Sn atoms on the surface of the formed SnO(2) nanowires due to the higher reducibility of Zn than Sn. Two strong Raman scattering peaks at 626 and 656 cm(-1) appeared in the micro-Raman spectrum of nc-ZnO/SnO(2) nanowires. The origins of the peaks were discussed. Most importantly, the method can be extended to other composite oxide nanowires that are synthesized by oxidizing two kinds of metals, such as high reducibility elements Mg, Al, Zn, and Ti, and low reducibility elements In, Ge, Ga, etc.     

吸光度比值-导数光谱法同时测定苯酚和间苯二酚

吸光度比值-导数光谱是近年来提出的多组分光谱分析法.该法以二元混合物的混合光谱与其中某一组分(被视为干扰组分)的标准光谱的比值对波长求导,从而得到吸光度比值-导数光谱.由于干扰组分对吸光度比值-导数光谱的贡献为零,所以可利用吸光度比值-导数值测出待测组分的含量.本文在普通分光光度计上用计算法完成了吸光度比值导数运算,同时测定了复方雷琐辛涂剂中苯酚(P)和间苯二酚(R)的含量,取得了较为满意的结果.     

Synthesis of triphenylamine-cored dendritic two-photon absorbing chromophores

[structure: see text]. A new series of dendritic two-photon absorbing chromophores containing triphenylamine moiety as a core or branching points have been synthesized through a convergent synthetic strategy. One-photon and two-photon optical properties of these molecules were characterized. In the nanosecond time domain, these molecules exhibited large two-photon absorption (TPA) cross sections up to 7.56-12.2 x 10(-44) s cm(4) at 800 nm, indicating that these molecular structures were viable candidates for various two-photon related applications.     

X射线显微术

综述了Ｘ射线显微术的基本原理，成像模式和技术及其在生命科学，材料科学等方面应用的新进展，同时简述了Ｘ线射显微术应用过程中应注意的几个问题。     

A PRIORI ESTIMATE FOR LOWER SOLUTIONS OF ACLASS QUASILINEAR ELLIPTIC EQUATIONS

LetGbeaboundeddomaininthen-dimensionEuclideanspaceE",I相似文献   

甘油对白酒中甲醇含量测定的影响

应用水浴控温(<90℃)蒸馏,可消除化学比色法测定白酒中甲醇含量时甘油的干扰,效果良好。     

A Bowen type rigidity theorem for non-cocompact hyperbolic groups

We establish a Bowen type rigidity theorem for the fundamental group of a noncompact hyperbolic manifold of finite volume (with dimension at least 3).      

Composition operators on Hardy spaces of Riemann surfaces

Our purpose is to define composition operators acting upon Hardy spaces of Riemann surfaces. In terms of counting functions related to analytic self-map on Riemann surfaces, the boundedness and compactness are characterized.     

Remarkable durability of the antibacterial function achieved via a coordination effect of Cu(II) ion and chitosan grafted on cotton fibers

Cellulose - We report here a simple and effective method applying a combination of chitosan (Cs) and Cu(II) ion to fabricate antibacterial cotton fabric with a remarkable durability against...     

Electronic and thermodynamic properties of ReB2 under high pressure and temperature

First-principles calculations of the crystal structures of rhenium diboride (ReB₂) have been carried out with the plane-wave pseudopotential density functional theory method. The calculated values are in very good agreement with experimental data as well as with some of the existing model calculations. The quasi-harmonic Debye model, using a set of total energy versus molar volume obtained with the first-principles calculations, is applied to the study of the thermal and vibrational effects. The structural parameters, thermal expansions, heat capacities, Grüneisen parameters and Debye temperatures dependence on the temperature and pressure are obtained in the whole pressure range from 0 to 70 GPa and temperature range from 0 to 2000 K as well as compared with available data.