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.     

Shape of Fano resonance line spectra calculated for silver nanorods

Using theoretical tools, we numerically demonstrated Fano line shapes in the scattering spectra of silver rods resulting from different mechanisms. One of the Fano line shapes is due to the coupling of an in-plane quadrupole and a dipole mode in a single rod. Two nodes were observed at the resonance wavelength, each of which is located at a quarter of the rod length from the two ends. The Fano resonance is strengthened when the silver rod is cut at the two nodal positions. The second mechanism that gives rise to a new Fano resonance peak occurs when the symmetry of the rod is broken and is a result of the asymmetric coupling between the two excited dipoles.     

快速ESPRIT谐波集检测算法

在各种高分辨谐波检测算法中,TLS-ESPRIT估计精度较高,因不需要谱峰搜索而具有较小的运算量。提出了一种快速ESPRIT算法,在不降低谱估计性能条件下,进一步减小了运算量。快速ESPRIT算法所需采样时间短,仅需两次特征值分解。分析表明,此算法可以检测不同飞行状态的直升机声信号谐波集,是一种实时性好、有效实用的目标谱集探测方法。     

一种基于信号功率的水声通信线性调频同步信号自适应阈值检测算法

由于线性调频信号具有一定的抗多普勒效应能力,在水下突发通信中作为同步序列得到了广泛的应用。在对线性调频信号进行同步的过程中发现,当采用固定判决门限检测方法时,往往会造成检测概率的减小或者虚警概率的增大,针对这一问题,本文提出了一种根据信号功率,并在滑动窗口中进行比较判决,自动调整相关峰检测门限值的自适应算法。通过仿真和湖试验证,该方法性能良好,具有一定的实用价值。     

多核DSP在无人平台探测声纳中的应用研究

在信息技术日益成熟的今天,无人平台在军事和民用领域都扮演着越来越重要的角色。水下无人航行器探测已经成为水声领域重要前沿研究方向,高速运算处理能力更是整个系统的核心。本文以多核DSP作为处理核心,提出了一个水下无人平台探测声呐架构。首先对多核DSP性能做了基本介绍,并以几种基本运算和经典波束形成算法作为例子进行了说明,通过性能测试证明了这一架构适用于水下无人平台的实时信号处理。这一多核DSP架构的设计和应用在水声领域中具有一定实用价值。     

Multipath structure of the typical under-ice sound channel in the Arctic:theory and experiment

Considering the typical acoustic environment of the Arctic, this paper proposes a method based on OASES-Bellhop coupled model to rapidly analyze the multipath structure of the under-ice sound channel. Firstly the proposed model refers to ice plate as stratified elastic media with some roughness. Secondly,it uses the perturbation method and Kirchhoff approximation theory to solve the scattering loss due to the sea ice inhomogeneity. Finally, the model predicts the multipath structure of the under-ice channel through Ray theory. The results of the numerical simulation and experiment indicate that the typical Arctic sound channel presents multipath structures due to the sea ice and seabed in the range of 6 km, respectively.The sea ice reflection paths are stable,with a short multipath spread within 14 ms. The seabed reflection paths have relatively weak strength. The proposed OASES-Bellhop coupled model successfully predicts the amplitude and delay of the multipath structure with small error,which indicates the proposed model is able to analyze and predict the multipath structure of the observed acoustic environment in experiment.     

Regioselective C–S bond formation accomplished by copper-catalyzed regioselective C–F substitution of perfluoroarenes with aryl thioacetates or benzyl thioacetate

Practical and straightforward method for regioselective C–S bond formation accomplished by copper-catalyzed regioselective C–F substitution of electron-deficient perfluoroarenes with aryl thioacetates or benzyl thioacetate has been developed. Because of its high reaction efficiency, good chemoselectivity and regioselectivity, and excellent functional-group compatibility, this protocol provides a useful and operationally simple access to polyfluoroaryl thioethers used for drugs and material chemistry.