Recent Advances in Rare‐Earth Polypnictides

The polypnictide complexes of rare earth cations have drawn the attention of the scientific community for their uncommon bonding modes and potential applications. Herein, we present a systematic and comprehensive summary on recent advances in the field of rare earth polypnictides, focusing on their synthesis, structures, and reactivities. The structural stabilizing effects imposed by the electropositive rare earth cations as well as the reducing capability of rare earth precursors in the synthesis of these polypnictide complexes are described in this review. We also disscuss in detail the bonding interactions and coordination modes between rare earth cations and polypnictide clusters as well as the similarities and the peculiarity of some structures.     

Surface Modification of Fine Particles with a SnO<Subscript>2</Subscript> Film by Using a Polyhedral-Barrel Sputtering System

Fine particles were modified with a thin film of SnO₂ by using a barrel sputtering system that is a dry process. The conditions for the preparation of SnO₂ were studied by reactive sputtering onto a glass plate substrate. The optimal conditions for the preparation of tetragonal SnO₂ were identified as 60% partial oxygen pressure and 1.0 Pa total gas pressure with the substrate at room temperature. Under the optimized conditions, the surfaces of Al flake particles were modified with a thin film of SnO₂. XRD and SEM/EDS analysis of the prepared samples showed that the Al particle surfaces were uniformly modified by a thin film of SnO₂ in all cases. The film thicknesses were 80, 130, and 180 nm at RF outputs of 195, 350, and 490 W. These measured thicknesses coincided with the values estimated from the interference colors of the samples.     

Biocomposites of covalently linked glucose oxidase on carbon nanotubes for glucose biosensor

The formation of covalently linked composites of multi–walled carbon nanotubes (MWCNT) and glucose oxidase (GOD) with high-function density for use as a biosensing interface is described. The reaction intermediates and the final product were characterized by using FT–IR spectroscopy, and the MWCNT-coated GOD nanocomposites were examined by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Interestingly, it was found that the GOD–MWCNT composites are highly water soluble. Electrochemical characterization of the GOD–MWCNT composites that were modified on a glassy carbon electrode shows that the covalently linked GOD retains its bioactivity and can specifically catalyze the oxidation of glucose. The oxidation current shows a linear dependence on the glucose concentration in the solution in the range of 0.5–40 mM with a detection limit of 30 μM and a detection sensitivity of 11.3 μA/mMcm². The present method may provide a way to synthesize MWCNT related composites with other biomolecules and for the construction of enzymatic reaction-based biofuel cells and biosensors. Supported by grants from the National Natural Science Foundation of China (NSFC, No. 20125515; 90206037; 20375016) and the Natural Science Foundation of Jiangsu Province (Grant No. BK 2004210)     

Synthesis and aggregation behavior of <Emphasis Type="Italic">N</Emphasis>-succinyl-o-carboxymethylchitosan in aqueous solutions

A simple and novel method was developed to successfully synthesize N-succinyl-O-carboxymethylchitosan (NSOCMCS) using N-acylation of chitosan with succinic anhydride. The NSOCMCS structure was characterized by Fourier transform infrared and ¹H nuclear magnetic resonance. The aggregation behaviors of NSOCMCS were studied using fluorescence spectroscopy, dynamic light scattering, and atomic force microscopy techniques. The critical aggregation concentration of NSOCMCS in water was determined to be 0.2–0.3 mg/ml. The apparent hydrodynamic radium of an NSOCMCS aggregate was dependent on the concentration. The aggregates demonstrated a much swollen association conformation in aqueous solution. The possible aggregation mechanisms for the NSOCMCS in water are discussed. Moreover, a driving force to form an open aggregation morphology was revealed in this study. Aggregation behaviors are important physicochemical properties of NSOCMCS, which impact the potential application in the biomedical field.     

Development of the FTIR properties of nano-structure silica gel doped with different rare earth elements,prepared by sol-gel route

Structural characteristics of pure silica gel (silica-xerogel, SiO₂) and silica gel doped with some rare earth elements (REEs) such as, praseodymium Pr³⁺, and Europium Eu³⁺, Erbium Er³⁺ and Holmium Ho³⁺ ions, with different concentrations ranging from 1 up to 6%, in the form of monolith materials were prepared by sol-gel technique, Using tetra-ethoxysilane as precursor materials, which are of particular interest for sol-gel integrated optics applications. Some structural features of sol-gel derived monolith are analyzed, namely the structure of nano-particle momolith samples, based on X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR). We show that the XRD spectra of α-crystobalite are obtained for the pure samples at 1100°C and even by doping with the four REEs ions.     

TiO(2) porous electrodes with hierarchical branched inner channels for charge transport in viscous electrolytes.

Titanium dioxide (TiO(2)) photoelectrodes with micro/nano hierarchical branched inner channels have been prepared by an electrohydrodynamic (EHD) technique and assembled to form dye-sensitized solar cells (DSSCs). Excellent penetration of ionic-liquid electrolytes and enhanced light harvesting in the longer wavelength region are realized within the composite-structure electrode, thus a better fill factor (ff) of 75.3 % and higher conversion efficiency (eta) of 7.1 % are obtained for viscous ionic-liquid electrolytes compared to pure nanostructured films. Hierarchical branched channels in the photoanodes can efficiently improve the transport properties of redox-active species in viscous electrolytes, which is demonstrated by electrical impedance spectroscopy (EIS). The incident monochromatic photon-to-electron conversion efficiency (IPCE) shows that enhanced light scattering in the composite film is of benefit for light harvesting and thus for solar energy conversion efficiency.     

硝酸肼的量热研究

用精密自动绝热量热计测定了在220 K—370 K温度范围内硝酸肼的热容、熔化热、熔化温度和熔化熵。所得热容数据的精密度以百分偏差的均方根值表示为±0.2％。三次熔化热测定的相对偏差为±0.1％。为验证结果的可靠性, 用该装置测定了冰的熔化热和熔化温度, 其结果与文献值一致; 又用法国SETARAM公司的高温量热计测定了硝酸肼的熔化热和熔化温度, 其结果与我们用量热法测定的结果一致; 从量热结果计算出了该试样的纯度, 该结果亦与化学分析的结果一致。这些均可说明我们所测得的数据是可靠的。     

在PVA存在下Os-SnCl_2-亮绿离子缔合体系的研究高纯镍中微量Os的测定

本文研究了Os-SnCl_2-PVA-亮绿离子缔合体系的显色反应,摩尔吸光系数ε_(434)为5.6×10~6L·mol~(-1)·cm~(-1),锇含量在0.1～0.7μg/25mL范围内遵守比耳定律,室温下显色后,吸光度在110min内稳定。研究了30种外来离子的影响,并进行了高纯镍中微量锇的测定。     

交联网络和浓溶液中高分子链运动的NMR研究Ⅲ.质子自旋-晶格弛豫时间与凝胶和浓溶液体系中高分子链段的运动

用自旋－晶格弛豫时间（Ｔ１）研究了溶胀的交联聚丙烯酰胺－丙烯酸网络和线型聚苯乙烯溶液中质子的弛豫行为。交联网络中，随着交联度增大，Ｔ１ＣＨ／Ｔ１ＣＨ２的值由１．１７逐渐趋近于１；而线型聚苯乙烯溶液中，Ｔ１ＣＨ／Ｔ１ＣＨ２的值由最稀浓度下的１．７过渡到１。说明在交联网络中，交联度很低时，链段的运动已经相当受约束；但交联度很大时，充分溶胀的交联网络中链段运动仍有一定自由度。而在线型高分子浓溶液中，链段的运动严重受阻，导致自旋扩散效应非常完全，彻底平均掉了各质子间Ｔ１时间的差异。