交通网络拓扑结构及特性研究综述

物联网中涉及的交通网络主要包括航空网络、海运网络、公共交通网络及城市道路网络.首先,列举了这些交通网络抽象为复杂网络的常用方法.然后,对交通网络研究中的主要特征参数进行了讨论.最后,对近年来国内外各类交通网络的研究成果进行了总结,并提出了未来可能的研究方向.     

Electrochemical Performance of Graphitic Multi-walled Carbon Nanotubes with Different Aspect Ratios as Cathode Materials for Aluminum-ion Batteries

Graphitic multi-walled carbon nanotubes (MWCNTs) can function as high-performance cathode materials for rechargeable Al-ion batteries with well-defined discharging plateaus and reasonable charge/discharge C-rates. However, the main intercalation/deintercalation or adsorption/desorption path of AlCl₄⁻ anions into or onto G-MWCNTs has not been elucidated. Herein, we used battery cells comprised of G-MWCNTs with different aspect ratios, Al metal, and AlCl₃/1-ethyl-3-methylimidazolium chloride ionic liquid as the cathode, anode, and electrolyte, respectively. The electrochemical performance of the Al||G-MWCNT cell increased as the aspect ratio of the G-MWCNT cathode increased (i. e., longer and thinner). The degree of defects of the G-MWCNTs was similar (0.15–0.22); hence, the results confirm that the main and alternate paths for the AlCl₄⁻ intercalation/de-intercalation or adsorption/desorption into/from or onto/from the G-MWCNT are the basal and edge planes, respectively. The step-like structures of defects on the basal plane provide the main reaction site for AlCl₄⁻ anions.     

Synthesis and characterization of well‐defined [polystyrene‐b‐poly(2‐vinylpyridine)]n star‐block copolymers with poly(2‐vinylpyridine) corona blocks

This article describes the synthesis and characterization of [polystyrene‐b‐poly(2‐vinylpyridine)]_n star‐block copolymers with the poly(2‐vinylpyridine) blocks at the periphery. A two‐step living anionic polymerization method was used. Firstly, oligo(styryl)lithium grafted poly(divinylbenzene) cores were used as multifunctional initiators to initiate living anionic polymerization of styrene in benzene at room temperature. Secondly, vinylpyridine was polymerized at the periphery of these living (polystyrene)_n stars in tetrahydrofuran at ?78 °C. The resulting copolymers were characterized using size exclusion chromatography, multiangle laser light scattering, ¹H NMR, elemental analysis, and intrinsic viscosity measurements. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3949–3955, 2007     

La4(P2O7)3：Ce,Gd,Tb磷光体的合成与光谱性质

本文首次采用溶液沉淀法合成了一系列La4(P2O7)3;Ce,Gd,Tb磷光体.经X射线分析表明,它们属于纯的La4(P2O7)3相。测定了这些化合物的激发和发射光谱、相对亮度及Ce3+的发光寿命,观察到在此基质中Ce3+与Gd3+的光谱重叠,它们之间存在着一定的相互作用,使(La0.64Ce0.3Gd0.064(P2O7)3的亮度比(La0.7Ce0.34(P2O7)3和(La0.94Gd0.064(P2O7)3有少许增加.此外,Ce3+能有效地敏化Tb3+9,从而大大增强Tb3+的发射.然而,Gd3+与Tb3+共存时存在着竞争吸收和独自发射,使(La0.80Gd0.06Tb0.144(P2O7)3的亮度与单掺的(La0.86Tb0.144(P2O7)3相比有少许降低.相应地在Ce,Gd和Tb共掺时,由于Gd3+的影响,使Tb3+的发射减弱,从而总的发光相对亮度有所降低。     

无长链天然卟啉的LB膜制备与光谱研究

本工作对无长链天然血卟啉(HP),原叶啉(PP)和卟啉C行进了LB膜的成膜探索,制备了单层、多层以及与硬脂酸、卵磷脂混合后的复合LB膜.对它们进行了紫外——可见吸收光谱、荧光光谱和时间分辨荧光光谱的研究,发现在LB膜中荧光寿命是一个很好的表征手段.     

A switchable fluorescent quantum dot probe based on aggregation/disaggregation mechanism

Here we report a facile switchable fluorescent QD probe for F(-) ions, which is based on the hydrogen bonding-driven aggregation and the analyte-triggered disaggregation.     

Solar cells sensitized with type-II ZnSe-CdS core/shell colloidal quantum dots

Type-II quantum dots (QDs) were applied for QDs-sensitized solar cells for the first time and showed prominent absorbed photon to current conversion efficiency.     

Organic redox couples and organic counter electrode for efficient organic dye-sensitized solar cells

A series of organic thiolate/disulfide redox couples have been synthesized and have been studied systematically in dye-sensitized solar cells (DSCs) on the basis of an organic dye (TH305). Photophysical, photoelectrochemical, and photovoltaic measurements were performed in order to get insights into the effects of different redox couples on the performance of DSCs. The polymeric, organic poly(3,4-ethylenedioxythiophene) (PEDOT) material has also been introduced as counter electrode in this kind of noniodine-containing DSCs showing a promising conversion efficiency of 6.0% under AM 1.5G, 100 mW·cm(-2) light illumination. Detailed studies using electrochemical impedance spectroscopy and linear-sweep voltammetry reveal that the reduction of disulfide species is more efficient on the PEDOT counter electrode surface than on the commonly used platinized conducting glass electrode. Both pure and solvated ionic-liquid electrolytes based on a thiolate anion have been studied in the DSCs. The pure and solvated ionic-liquid-based electrolytes containing an organic redox couple render efficiencies of 3.4% and 1.2% under 10 mW·cm(-2) light illumination, respectively.     

Methemoglobinemia caused by 8-aminoquinoline drugs: DFT calculations suggest an analogy to H4B's role in nitric oxide synthase

We suggest a possible mechanism of how 8-aminoquinolines (8-AQ's) cause hemotoxicity by oxidizing hemoglobin to methemoglobin. In our DFT calculations, we found that 5-hydroxyprimaquine is able to donate an electron to O(2) to facilitate its conversion to H(2)O(2). Meanwhile, Fe(II) is oxidized to Fe(III) and methemoglobin is formed. In this mechanism, the 8-AQ drug plays a similar role as that of H(4)B in nitric oxide synthase. Furthermore, our study offers an approach to inform the design of less toxic antimalarial drugs.     

DNA directed self-assembly of anisotropic plasmonic nanostructures

Programmable positioning of one-dimensional (1D) gold nanorods (AuNRs) was achieved by DNA directed self-assembly. AuNR dimer structures with various predetermined inter-rod angles and relative distances were constructed with high efficiency. These discrete anisotropic metallic nanostructures exhibit unique plasmonic properties, as measured experimentally and simulated by the discrete dipole approximation method.