线阵CCD全饱和单侧拖尾特性分析

在用532 nm连续激光辐照TCD-1200D型线阵CCD的过程中,发现了光斑的全饱和单侧拖尾现象。为了分析这种现象的特性,实验测量了拖尾长度随激光功率、CCD积分时间和CCD驱动频率的关系,发现拖尾长度随着激光功率和积分时间的增加而增加,但在一定范围内与CCD驱动频率无关。通过理论计算和实验数据分析拟合发现,拖尾长度和激光功率密度和积分时间的乘积有关,并根据激光辐照下CCD器件光生电荷量的产生过程,推导出了拖尾长度与CCD势阱光生电荷量的关系,得到了拖尾长度随光生电荷量的变化曲线,为全饱和单侧拖尾现象机理分析提供了数据支持。     

无规聚甲基丙烯酸甲酯立构复合的红外光谱研究

用红外光谱研究了无规聚甲基丙烯酸甲酯的丙酮、苯、氯仿溶液成膜样品的立构复合状况。结果表明无规聚甲基丙烯酸甲酯在丙酮和苯中确能形成立构复合结构,结构的形成主要是依靠分子链中间规和等规链段的相互作用。对丙酮样品的退火实验表明,在退火过程中能够发生间规链段的自聚集现象。     

Polycrystalline silicon thin films prepared by Ni silicide induced crystallization and the dopant effects on the crystallization

Intrinsic and doped polycrystalline silicon thin films were grown by the Ni silicide seeds induced crystallization. The Ni first reacted to Si forming a silicide seeds, then these seeds act as nuclei, from which the grains start to grow laterally. Compared with traditional Ni induced lateral crystallization, polycrystalline silicon thin film was grown by Ni silicide induced crystallization with low Ni contamination and large grain sizes. It can be found that the Ni silicide induced crystallization rate is accelerated by p-type doping and is decelerated by n-type doping. And the slightly and strongly phosphorous-doped polycrystalline silicon can be obtained with different grain shapes. Also, the sheet resistance of doped polycrystalline silicon decreases with the increasing of the doping atoms. A reasonable explanation is presented for the dopant effects on the growth rate, microstructure and electronic properties of the samples.     

Engineering nonspherical hollow structures with complex interiors by template-engaged redox etching

Despite the significant advancement in making hollow structures, one unsolved challenge in the field is how to engineer hollow structures with specific shapes, tunable compositions, and desirable interior structures. In particular, top-down engineering the interiors inside preformed hollow structures is still a daunting task. In this work, we demonstrate a facile approach for the preparation of a variety of uniform hollow structures, including Cu(2)O@Fe(OH)(x) nanorattles and Fe(OH)(x) cages with various shapes and dimensions by template-engaged redox etching of shape-controlled Cu(2)O crystals. The composition can be readily modulated at different structural levels to generate other interesting structures such as Cu(2)O@Fe(2)O(3) and Cu@Fe(3)O(4) rattles, as well as Fe(2)O(3) and Fe(3)O(4) cages. More remarkably, this strategy enables top-down engineering the interiors of hollow structures as demonstrated by the fabrication of double-walled nanorattles and nanoboxes, and even box-in-box structures. In addition, this approach is also applied to form Au and MnO(x) based hollow structures.     

高聚物的动态红外光谱研究

动态红外光谱法是研究高聚物在外加力场作用下变形或松弛现象的极为有用的手段。本文介绍了动态红外光谱法的实验技术以及若干近期的研究结果。     

TiO2 and SnO2@TiO2 hollow spheres assembled from anatase TiO2 nanosheets with enhanced lithium storage properties

TiO(2) and SnO(2)@TiO(2) hollow spheres assembled from anatase TiO(2) nanosheets with exposed (001) high-energy facets are constructed via a templating approach, and the as-prepared samples exhibit enhanced lithium storage properties.     

Facile Synthesis of Porous MnO Microspheres for High‐Performance Lithium‐Ion Batteries

Manganese oxide is a highly promising anode material of lithium‐ion batteries (LIBs) for its low insertion voltage and high reversible capacity. Porous MnO microspheres are prepared by a facile method in this work. As an anode material of LIB, it can deliver a high reversible capacity up to 1234.2 mA h g^?1 after 300 cycles at 0.2 C, and a capacity of 690.0 mA h g^?1 in the 500th cycle at 2 C. The capacity increase with cycling can be attributed to the growth of reversible polymer/gel‐like film, and the better cycling stability and the superior rate performance can be attributed to the featured structure of the microspheres composed of nanoparticles with a short transport path for lithium ions, a large specific surface, and material/electrolyte contact area. The results suggest that the porous MnO microspheres can function as a promising anode material for high‐performance LIBs.     

Highly water-soluble nanocrystal powders of magnetite and maghemite coated with gluconic acid: Preparation, structure characterization, and surface coordination

A simple method was developed to prepare highly water-soluble nanocrystal powders of magnetic iron oxides with different oxidation degree from magnetite (Fe(3)O(4)) to maghemite (γ-Fe(2)O(3)) coated with gluconic acid (GLA). X-ray diffraction and transmission electron microscopy measurements show that the products have a narrow size distribution, and the cores are inverse spinel iron oxides and completely crystallized. Vibrating sample magnetometry measurements reveal that all the samples exhibit superparamagnetic behavior at room temperature. Fourier transform infrared (FTIR) and Raman spectra were used to identify the products. It is shown that GLA molecules are immobilized on the nanoparticle surface by chemical bonding and the carboxyl is asymmetrically bound to the surface iron atom, and the vacancies in the γ-Fe(2)O(3) cores are disordered. Compared with FTIR, Raman spectrum analysis is a rapid, simple, and accurate method for identifying inverse spinel iron oxides. The chemical stability and the high solubility of the products are explained in terms of the proposed coordination modes of the surface iron atom with GLA.     

Reflection–absorption infrared spectroscopy investigation of the crystallization kinetics of poly(ethylene terephthalate) ultrathin films

Reflection–absorption infrared spectroscopy was used to study the crystallization behavior of poly(ethylene terephthalate) (PET) ultrathin films. The crystallinity of ultrathin films was estimated by the fraction of trans conformers of PET. The isothermal and nonisothermal crystallization kinetics of ultrathin films with different thicknesses were investigated. The thinner PET film showed slower kinetics during isothermal crystallization than the thicker film. Moreover, the final crystallinity of films with various thicknesses were reduced with decreasing thickness. An Avrami equation was used to fit the acquired results. The Avrami exponents decreased with the film thickness. As for the nonisothermal crystallization, the cold‐crystallization starting temperature shifted to a lower temperature as the film thickness increased. The influence of the substrate on the crystallization kinetics of the films was also studied. The half‐crystallization times and final crystallinities of ultrathin films adsorbed onto a self‐assembled‐monolayer‐treated surface and an untreated substrate were clearly different, although their thickness dependence was similar. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4440–4447, 2004