紫精类化合物分子聚集体材料的界面组装

紫精类化合物具有良好的电化学活性,并且在发生氧化还原反应时伴有颜色的变化,在膜修饰电极、电致变色材料和分子器件的研制等方面受到广泛的关注。紫精中的烷基链非常易于进行化学修饰,因而比较适合于通过自下而上的分子自组装技术制备多功能的分子和纳米材料。本文综述了利用Langmuir-Blodgett法、自组装法和层层组装法制备紫精分子聚集体材料的研究进展,并讨论了分子聚集体薄膜中紫精的结构、电致变色、电化学氧化还原特性及其在研制超分子器件方面的应用。     

The investigation on the electronic structures of hybrid GNR-ZnO

To investigate the modification of graphene for a good semiconductor performance, the model of graphene nanoribbon (GNR) and the model of hybrid GNR-ZnO are presented, respectively. The electronic structures such as band structure, density of electronic states (DOS) are investigated by using first-principles calculations based on density functional theory. The results show that the ZnO has direct contribution to the formation of valence band with the composites, which changes the properties of graphene; the adsorption of ZnO nanostructure has an impressive impact on the graphene nanoribbon, which causes the band gap of the composite to become narrower than that of intrinsic graphene nanoribbon. In terms of the graphene nanoribbon, its differentiation of 2p state weakens gradually from the marginal zone to the central region. The mechanism of electronic structure of the graphene nanoribbon and hybrid GNR-ZnO is also discussed to give a further explanation for the change. The results provide a potential way to improve the properties of intrinsic graphene and enhance the controllability of graphene-based materials structure.     

不同营养液对铁皮石斛生长及多糖含量的影响

探讨不同营养液在铁皮石斛生长和多糖积累中的影响,以期筛选出铁皮石斛专用营养液,为铁皮石斛合理施肥提供科学依据。以铁皮石斛组培苗为试验材料,炼苗移栽15d后对开始其喷施不同配比营养液,每10d喷施1次,共喷22次。以花多多1号（N:P₂O₅:K₂O=20:20:20）为对照,用N、P、K和Ca肥按正交设计组成4因子3水平的9个处理组,研究不同配比营养液对铁皮石斛株高、茎粗及多糖含量的影响。与对照组相比,N1P3K3Ca3处理下株高最佳,为15.42cm,高于对照组（7.32cm）;N₃P₃K₂Ca₁处理下茎粗最好,为11.20 mm,粗于对照组（2.16mm）;N1P3K3Ca3处理下多糖含量最高,为14.54%,高于对照（6.43%）。K是影响株高的主要因素,其次为P、N、Ca;P是影响茎粗的主要因素,其次为K、Ca、N;K影响多糖含量的主要因素,其次是P、N、Ca。综合分析得出既有利于生长又有利于提高营养成分的铁皮石斛专用营养液配比为N1P3K3Ca1。     

Preparation of Cu nanoparticles with controlled particle size and distribution via reaction temperature and sonication

This paper presents metallic copper nanoparticles (CuNPs) that differ according to the process parameters used, such as bath temperature and sonication. The effect of different reactions on the size and distribution of CuNPs that had been formed in ethylene glycol solvent were characterized by the X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses after extraction from the solvent. The optimal dimensional properties, including size, distribution, and agglomeration, of CuNPs were determined by controlling the reaction temperature. On the other hand, the mechanically induced sonication process enhances the formation of the selective CuNPs because of the many homogeneous interactions among precursors, reducing agents, and capping agents related to the nucleation and growth of CuNPs. The mechanics of the origin of the diverse CuNPs of different size and distribution are discussed. Copyright © 2016 John Wiley & Sons, Ltd.     

Novel electrical properties of nanoscale thin films of a semiconducting polymer: quantitative current-sensing AFM analysis

Thin films (20-150 nm thickness) of poly(o-anthranilic acid) with various doping levels were prepared on silicon substrates with deposited indium tin oxide, and their topography and current-voltage (I-V) characteristics were quantitatively investigated using current-sensing atomic force microscopy with a platinum-coated tip. The films were found to have a surface morphology like that of orange peel, with a periodic modulation and a surface roughness. The films exhibited nonuniform current flows and I-V characteristics that depended on the doping level as well as on the film thickness. Films with a high doping level were found to exhibit Zener diode switching behavior, whereas the films with a very low doping level (or that were dedoped) exhibited no current flow at all, and so are insulators. Interestingly, self-doped films (which are at an intermediate doping level) were found to have a novel electrical bistability, i.e., a switching characteristic like that of Schottky diodes, and increasingly insulating characteristics as the film thickness was increased. The films with thickness < or =62 nm, which exhibited this novel and stable electrical bistability, can potentially be used in the fabrication of high-density, stable, high-performance digital nonvolatile memory devices based only on transistors. The measured current images and I-V characteristics indicate that the electrical switching and bistability of the films are governed by local filament formation and charge traps.     

锆-EDTA-(口底)唑体系混配型络合物的分光光度法研究及其应用

本文研究了锆-EDTA-(口底)唑混配型络合物的显色条件,表明在pH5.6-6.6形成了Zr(Ⅳ):EDTA:(口底)唑=1:1:1的稳定络合物,ε=2.81×10⁴(λ_max=503nm);锆在0-50微克/25毫升遵守比耳定律。并测定了镍基高温合金及铝镁合金中的微量锆,得到了满意的结果。     

爆炸冲击振动下人体抛离问题的分析

采用单自由度模型研究了爆炸冲击振动下人体抛离问题。提出了人体抛离的飞离条件,推导了人体飞离时刻和飞离速度计算公式,为定量研究爆炸冲击振动下人员冲击伤和碰撞伤及人员隔冲问题提供了参考。     

Low-temperature growth of GaN by atomic nitrogen based on a dielectric barrier discharge

GaN films were deposited on sapphire(0 0 0 1) and Si(1 0 0) substrates by MOCVD using an atomic nitrogen source based on a dielectric barrier discharge (DBD) method. Molecule nitrogen and trimethylgallium (TMG) were separately delivered to the substrates. Wurtzite GaN films, with no trace of cubic GaN, were successfully grown on -Al₂O₃ substrates even at relatively low temperatures (<800°C). Sapphire substrate RMS roughness was 5.01 and 4.93 Å before and after the exposure to DBD N-source, respectively. This shows negligible irradiation damage of accelerated N₂⁺ ion as well as the effect of smoothening the substrate surfaces with DBD N-source. The PL results exhibited small luminescence at the spectral region of blue and UV but a luminescence around the yellow region (2.5 eV) was detected. This is caused by oxygen impurity from AES analysis.     

两两NQD列的强收敛性

利用两两NQD列部分和矩不等式和截尾法,探讨了两两NQD列的完全收敛性和强大数定律,所获结论推广并改进了相关文献已有结果.     

In‐Depth TEM Investigation on Structural Inhomogeneity within a Primary LixNi0.835Co0.15Al0.015O2 Particle: Origin of Capacity Decay during High‐Rate Discharge

The structural stability of cathode materials during electrochemical reactions, in particular, under high‐rate discharge, is pertinent to the design and development of new electrode materials. This study investigates the structural inhomogeneity that develops within a single LiNi_0.835Co_0.15Al_0.015O₂ (NCA83) particle during a fast discharging process under different cutoff voltages. Some of the NCA83 particles discharged from a high cutoff voltage (4.8 V) developed surface areas in which the layered structure was recovered, although the interiors retained the degraded spinel structure. These micro‐ and nano‐scale structural inversions from high cutoff voltage seem highly correlated with structural evolutions in the initial charged state, and may ultimately degrade the cycling stability. This study advances understanding of the structural inhomogeneity within primary particles during various electrochemical processes and may facilitate the development of new Ni‐rich cathode materials.