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.     

Facile Total Synthesis of (±)‐Nimbiol

A facile total synthesis of (±)‐nimbiol 1 has been achieved. In order to decrease the dioxo byproduct 2a , an improved oxidation system of CrO₃/H₂O/HOAc/NaOAc was used.     

Two New Pyrrolizidines from Ligularia lankongensis

Two new pyrrolizidines named lankongensisine A (1), B (2) were isolated from the roots of Ligularia lankongensis collected in Lijiang, Yunnan, and their structures were established by spectroscopic analysis.     

Chiral attachment of styrene mediated by surface dimers on Ge100

We have investigated the chiral adsorption configurations of styrene on Ge(100) using scanning tunneling microscopy at 300 K. The chemisorbed styrene on a single Ge dimer reduces the symmetry of the molecule, which produces a chiral center, and leads to the (S) or (R) chiral on-top configuration. We have found that the dimeric adsorption of styrene induced by the Ge surface dimer structure forms the enantiomeric and diastereomeric paired end-bridge configurations. We determine the absolute chirality of adsorbed styrene on Ge(100) and demonstrate a novel method for the achiral molecule to produce dimeric enantiomers and diastereomers attached to the semiconductor surface.     

某些苯二醛类双Schiff碱及其双铜(Ⅱ)配合物研究

用2-甲氧基-5-氯-1,3-苯二甲醛与含有不同取代基团X的邻氨基酚缩合,合成了一系列双Schiff碱L-X(X=OMe,diMe,Me,t-Bu,H,Cl,NO_2),它们与乙酸铜(Ⅱ)作用生成了一系列的双核配合物Cu_2L-X(OEt).用红外、紫外、磁天平、顺磁共振等手段对配合物进行了表征,并通过量化计算(CNDO/2法)探讨了配合物的成键性质。研究结果表明,该类配合物是一个较大的共轭体系,配合物中Cu(Ⅱ).Cu(Ⅱ)之间有较强的反铁磁性交换作用,其共轭程度和交换作用强弱皆随X基团的不同而呈现某种变化规律。     

Studies on Chemical Constituents of Polygonum Ciliinerve Ohwi

Three new apianen lactones Maomailiaoine I ( 1 ), Maomailiaoine II ( 2 ) and Maoimaliaoine III ( 3 ), together with one known apianen lactone, five known flavonoids and three other known compounds were isolated from Polgonum ciliinerve Ohwi. Their structures were deduced from spectroscopic methods and 2D NMR techniques.     

Structural features of theClostridium thermocellum cellulase Ss gene

Applied Biochemistry and Biotechnology - TheClostridium thermocellum cellulase Ss is a subunit of the extracellular cellulase complex (cellulosome). It has previously been shown that Ss hydrolyzes...     

1－N－（苯并咪唑－1－乙酰基）－4－苯基－3－氨基硫脲金属配合物的合成及结构表征

合成了新配体１－Ｎ－（苯并咪唑－１－乙酰基）－４－苯基－３－氨基硫脲（ＢＰＭＳ），将其与Ｍｎ（Ⅱ）、Ｃｏ（Ⅱ）、Ｎｉ（Ⅱ）、Ｃｕ（Ⅱ）、Ｃｄ（Ⅱ）、Ｚｎ（Ⅱ）、ＵＯ２（Ⅱ）等金属的醋酸盐反应，合成了７个新配合物。所有化合物均经元素分析、ＩＲ、１ＨＮＭＲ和热重分析等表征。红外光谱表明，配体以四齿方式通过烯醇式羰基氧原子、烯醇式硫羰基硫原子以及Ｃ＝Ｎ１和Ｃ＝Ｎ２的氮原子与金属配位     

计算机模式识别法对甲状腺机能亢进症微量元素谱的研究

据Mahlanobis距离判别法，利用计算机多元统计判别程序，对14例甲亢思者和21例健康人的血清中锌、铁、铜、锰、镁和锶等元素浓度差异进行分类判别研究。选择锌、铁、钙、锶作判别特征参量时，患者和健康人的分类准确率为100％，服碘前与服碘后的甲亢患者分类准确率为92.7％，分类研究指出，甲亢患者血清中的铁和锶浓度高于健康人，经服碘治疗后，患者血清中上述元素浓度降低与健康人相近。