负载型复合半导体V2O5-TiO2/SiO2表面V2O5和TiO2的相互修饰作用

 采用表面改性法制备了负载型复合半导体材料V2O5-TiO2/SiO2,并用X射线衍射、比表面积测定、拉曼光谱、程序升温还原和紫外-可见漫反射光谱等技术对固体材料的结构和光响应性能进行了表征. 结果表明,V2O5和TiO2在负载型复合半导体V2O5-TiO2/SiO2表面有相互修饰的作用. 一方面,V2O5能扩展TiO2的光响应范围,使TiO2的吸光区域由紫外光区拓宽至可见光区,从而提高了复合半导体对光能的利用率; 另一方面,TiO2则有助于提高V2O5在载体表面的分散程度,抑制VOx的聚合,减小V2O5的微晶尺寸,提高固体材料的能隙值和氧化还原能力.     

基于识别能力的人脸特征向量均衡

在人脸识别中,通常是把人脸图像投影在特征向量组成的空间中,特征向量决定了人脸识别的效果。同一人的人脸图像在好的特征向量上的投影应具有较集中的分布,反之亦然。从微观意义上提出了每个向量的识别能力的概念,通过计算识别能力的大小,选择具有较大的识别能力的特征向量。为了使每个向量在识别中发挥与其识别能力相对应的作用,根据每个向量的识别能力对它们进行均衡化处理,赋予不同权重,提高了识别率。通过在ORL、Yale人脸数据库上进行试验,验证了该方法的有效性。     

Modeling of reinitiation ability of polymer brushes grown by surface‐initiated photoiniferter‐mediated photopolymerization

A kinetic model developed to investigate surface‐initiated photoiniferter‐mediated photopolymerization (SI‐PMP) and parameterized using experimental thickness data from SI‐PMP of methyl methacrylate is used to examine chain extension by reinitiation. Specifically, the effects of light intensity, concentration of an added deactivator, tetraethylthiuram disulfide (TED), and initial photoiniferter (PI) concentration on the reinitiation ability of surface‐tethered PMMA layers is examined in detail. The simulations show that while increases in [TED] and decreases in light intensity affect overall rates of PMMA layer growth in a similar fashion, their effect on reinitiation ability of PMMA layers is significantly different: reinitiation ability increases with increasing [TED] but it is not improved by decreases in light intensity. Simulations also suggest that polymer layers synthesized in the presence of TED have a greater tendency to form surface‐tethered block copolymers upon reinitiation compared with polymer layers synthesized without TED and at lower light intensity. While both [PI] and [TED] affect the reinitiation ability, the effect of [TED] on reinitiation ability is identical at a given [TED]/[PI] ratio for all PI and TED concentrations tested. These findings obtained from the rate‐based model are instrumental in delineating strategies for creating tethered block copolymer layers or mixed brushes by SI‐PMP. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1586–1593, 2010     

Planarity of ethylene/linear polyene analogues focused on π-electron holding ability of the components

Ethylene/polyene analogues composed of heavier group 14 elements, such as silicon and germanium, do not prefer a planar structure. In the repulsion dominant (RD) model of our previous study mainly focusing on the planarity of hexasilabenzene, it was demonstrated that electron repulsion promotes nonplanarization of heavy benzene analogues. In this study, we have investigated a correlation between intramolecular π-electron transfers (polarization effect) and planarity in various linear unsaturated compounds in order to deepen the RD model. Herein, it was revealed that the ability to hold π-electrons in the planar molecular structure is characteristic of each element. For example, carbon can hold more than one π-electron, whereas silicon and germanium cannot tolerate even one π-electron to keep the planar structure. Thus, π-accepting substituents on the heavy atom were found to make the heavy ethylenes and linear polyenes planar by controlling the number of π-electrons on each skeletal atom.     

Correlation of Cooperatively Localized Rearrangement on the “Fluidized Domain”of Polymers to Their Nonexponentially Viscoelastic Behavior and Lifetime at Double Aging Processes II: Estimation of Long-term Mechanical Behavior and Lifetime of Polymeric Mate

Three kinds of polymeric materials are taken as example for the verification of linear ex-trapolation method from unified master lines with reduced universal equations on creep and stress relaxation tests. The theoretical values of long-term mechanical behavior and lifetime for a cured epoxide, polypropylene, poly(methyl-methacrylate), and SBR rubber are directly evaluated with the universal equations on reduced creep compliance and reduced stress relax-ation modulus and are compared with their predicted values by the linear extrapolation from the unified master lines of creep and stress relaxation. The results show that the theoretical values of dimensional stability, bearing ability and lifetime are in an excellent agreement with the predicted values, it shows that the linear extrapolation method is more simple and reliable. The dependences of long-term mechanical behaviors and lifetime on the different aging times are discussed.     

可聚合非离子型表面活性剂的合成及其性能

由甲苯二异氰酸酯、丙烯醇和不同分子量的聚乙烯醇合成了3种可聚合非离子表面活性剂（Ⅱ-PEG400、Ⅱ-PEG1000和Ⅱ-PEG2000）,用FT-IR对分子结构进行了表征。 结果表明,随聚乙烯醇分子量的增加,非离子表面活性剂的电导率显著增加、表面张力由36.28 mN/m降低至31.30 mN/m、浊点由39.6 ℃增加至58.9 ℃,对丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)和甲基丙烯酸丁酯(BMA)的乳化能力均优于常用乳化剂OP-10,以AIBN作引发剂在70 ℃下既能均聚又可与丙烯酸酯进行共聚反应。     

基于一种新型杂化阳极修饰层的高效有机电致发光器件

设计了基于Bphen∶LiF、Al和MoO₃的杂化电荷注入层,并将其应用于有机电致发光器件中。实验研究表明,这种杂化层作为阳极修饰层是非常有效的,它可以增加器件中载流子注入的平衡性,提高器件的性能。相对参考器件,基于杂化阳极修饰层的电致发光器件的最大电流效率和最大功率效率均提高1.3倍左右。我们对器件性能及其提高的机理进行了分析。     

Effect of pulsed ultrasound on the physicochemical characteristics and emulsifying properties of squid (Dosidicus gigas) mantle proteins

Food technologists are always looking to improve the functional properties of proteins. In this sense, in last years ultrasound has been used to improve some functional properties. For this reason, and considering that jumbo squid is an important fishery in northwest Mexico, the purpose of this research was to determine the effect of pulsed ultrasound on the physicochemical characteristics and emulsifying properties of squid (Dosidicus gigas) mantle proteins. Pulsed ultrasound (20 kHz, 20, and 40% amplitude) was applied for 30, 60, and 90 s to a protein extract prepared from giant squid mantle causing an increase (p < 0.05) in surface hydrophobicity (S_o) from 108.4 ± 1.4 to 239.1 ± 2.4 after application of pulsed ultrasound at 40% of amplitude for 90 s. The electrophoretic profile and the total and reactive sulfhydryl contents were not affected (p ⩾ 0.05) by the ultrasound treatment. The emulsifying ability of the protein solution was improved (p < 0.05), whereas the Emulsifier Activity Index (EAI) varied from123.67 ± 5.52 m²/g for the control and increased up to 217.7 ± 3.8 m²/g after application of the ultrasound. The Stability Emulsifier Index (EEI) was improved at 40% of amplitude by 60 and 90 s. The results suggested that pulsed ultrasound used as pretreatment induced conformational changes in giant squid proteins, which improved the interfacial association between protein-oil phases, thus contributing to the improvement of their emulsifient properties.     

键合型聚丙烯酰胺衍生物手性固定相的制备与手性识别性能

高效液相色谱(HPLC)被广泛认为是分离制备光学纯单一对映体的最有效方法。在高效液相色谱手性拆分中,手性固定相(CSP)的性能直接影响到色谱柱的手性分离能力。在众多手性固定相中,键合型手性固定相具有溶剂耐受性好,分离模式灵活等优点,已经发展成为一类重要的手性固定相。本文通过两步化学反应合成了新型的光学活性丙烯酰胺衍生物--(S)-1-丙烯酰-2-(N-苯基甲酰胺基)吡咯烷((S)-APACP),采用核磁共振氢谱表征了(S)-APACP的化学结构;通过3步化学反应制备了键合型聚丙烯酰胺衍生物手性固定相,采用热重分析法表征了聚合物的键合量,采用HPLC评价了键合型手性固定相的识别能力,分析了影响其手性识别能力的因素。研究结果表明,APACP聚合物成功地键合到硅胶表面制备了具有良好溶剂耐受性的键合型手性固定相,其聚合物键合量为10.2%~11.8%,该键合型手性固定相对若干种对映体显示了较好的手性识别能力。