Co:BaTiO3纳米复合薄膜的制备及其结构

用脉冲激光沉积技术(PLD)在MgO(100)基底上生长了嵌埋Co纳米晶的BaTiO3复合薄膜. 分别利用x射线衍射(XRD)、原子力显微镜(AFM)以及拉曼光谱(Raman)对薄膜的微观结构、表面 形貌进行了表征. 结果表明该薄膜为c轴取向的四方晶体结构，薄膜表面均匀、致密、 具有原子尺度的光滑性，其均方根表面粗糙度(RMS)达到015nmCo以纳米晶形式嵌埋BaTi O3基体中，呈单分散性均匀分布，其粒径随激光脉冲数的增加而增大. Co：BaTiO3纳米 复合薄膜拉曼峰的强度随钴纳米晶粒径的增加明显减弱，但是峰的宽度逐渐增加. 关键词： Co：BaTiO3 纳米复合薄膜 脉冲激光沉积     

Application of 57Co emission Mössbauer spectroscopy to studying biocomplexes in frozen solutions

Emission Mössbauer spectroscopy with the ⁵⁷Co isotope was used to study very dilute rapidly frozen aqueous solutions of cobalt(II) complexes with low-molecular-weight biomolecules (aromatic amino acids – anthranilic acid and L-tryptophan) and within a sophisticated biopolymer, bacterial glutamine synthetase, a key enzyme of nitrogen metabolism. The appearance of after-effects of the ⁵⁷Co→⁵⁷Fe nuclear transformation as well as the coordination properties of the cation and the ligands in the complexes are discussed on the basis of their Mössbauer parameters.     

Room temperature 2 μm Tm,Ho : YLF laser

We present the results obtained with a Tm,Ho : YLF crystal, grown in the new crystals growth facility realized in the Dipartimento di Fisica of the Università di Pisa. The 2 μm laser performance has been studied for three different pump sources, a Ti : Sapphire, a diode—tuned at 792.7 nm—and a Co : MgF₂ laser, tuned at 1.682 μm.     

Hilbert空间中最终范数连续半群的特征条件

本文给出了Hilbert空间中当t>t0(t0≥0)时,按一致算子拓扑连续C0半 群T(t)的四个特征条件.     

Theoretical Calculations of g Factors and Hyperfine Structure Constants for Co2+ inCd2+(I) and Cd2+(II) Sites of CsCdCl3 Crystal

The g factors g‖,g⊥ and hyperfine structure constants A‖,A⊥ for two trigonal Co2+ centers (i.e.,Co2+ in Cd2+ (I) and Cd2+ (II) sites) in CsCdCl3:Co2+ crystals are calculated from the high-order perturbation formulas based on the cluster approach.In the calculation,the contributionsfrom covalency effect and configuration interaction effect are considered and the parameters related to both effects are obtained from the optical spectrum and the structure data of the studied system.The results are in good agreement with the observed values.     

Molecular orbital calculations of binuclear systems of Fe, Co and Ni derivatives of pentalene, s-indacene and as-indacene

Extended Hückel calculations on a whole family of dinuclear complexes of pentalene, s-indacene and as-indacene allow a general rationalization of the structural and physical features of these compounds, mainly based on their electron count.     

Cobalt-zeolite catalysts for the synthesis of hydrocarbons from CO and H2

Catalysts prepared by mechanical mixing of high-silica zeolite ZSM-5 with cobalt oxide Co₃O₄, basic cobaltous carbonate, and cobaltous carbonate were studied. The nature of the cobalt compound introduced into the mixture affects the catalytic and physicochemical properties of the catalyst. The presence of Co₃O₄ in the sample (introduced as oxide or obtained by thermal decomposition of the carbonate) is favorable to the formation of aromatic compounds from CO and H₂. The use of cobaltous carbonates for the preparation of catalysts results in development of the porous structure of the catalyst. During preparation of samples, the mechanical treatment partially destroys the zeolite framework of the support.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1070–1073, June, 1995.     

N,N—双水杨醛乙二胺合钴—全氟磺酸膜修饰电极的电化学研究

实验发现中性分子Ｎ，Ｎ－双水杨醛乙二胺合钴（Ｃｏ（ｓａｌｅｎ）可以通过简单浸泡进入全氟磺酸（Ｎａｆｉｏｎ）膜，形成具有稳定电化学响应的Ｃｏ（ｓａｌｅｎ）－ｎａｆｉｏｎ修饰电极，Ｘ射线光电子能谱表明，Ｃｏ（Ｓａｌｅｎ）中心钴原子能与Ｎａｆｉｏｎ膜中磺酸根基团形成轴向配位，而使其由＋２价变为＋３价状态，电化学研究表明，Ｃｏ（ｓａｌｅｎ）在Ｎａｆｉｏｎ膜中的电荷转移是电活性物迁移和电子跳适共同控制的，同     

Role of PVA in synthesis of nano Co3O4‐decorated graphene oxide

Polymeric materials have been found to be ideal candidates for the synthesis of organic–inorganic nanomaterials. We have obtained Co₃O₄‐decorated graphene oxide (GO) nanocomposites by a simple polymer combustion method. Polyvinyl alcohol (PVA) of two different molecular weights, 14,000 and 125,000, was used for the synthesis. The pristine sample was annealed at 300, 500, and 800°C. PVA has played an important role in the formation of GO and Co₃O₄ nanoparticles. Synthesized Co₃O₄–GO nanocomposites were characterized by X‐ray diffraction, Fourier transform infrared, Raman, electron paramagnetic resonance, transmission electron microscopy, and vibrating sample magnetometry. Reflection peaks at 12° and 37° in an X‐ray study confirm the formation of Co₃O₄–GO. Raman study validates the presence of GO in nanocomposites of Co₃O₄–GO. Room temperature ferromagnetism was observed in all annealed samples. The highest coercivity of 462 G was observed for 300°C annealed samples as compared with bulk Co₃O₄. On the basis of the results obtained, a mechanism of formation is proposed. Copyright © 2015 John Wiley & Sons, Ltd.