吲哚染料的电荷转移和能量转移:应用于无金属的染料敏感太阳能电池

Metal-free indoline dyes for dye-sensitized solar cells were studied by employing quantum chemistry methods.Comparative study of the properties of both ground and excited states of metal-free indoline dyes for dye-sensitized solar cells revealed: (i) as the number of rhodanine rings increases, the energy di?erence betweenHOMO and LUMO decreases and there is a red shift in the absorption spectrum with the binding energyincreased, and the transition dipole moment decreased; (ii) Based on an analysis of charge di?erential density,we observed that the charge and energy are transfered from the phenylethenyl to the indoline and rhodaninerings; (iii) The electron-hole coherences are mainly on the indoline and rhodanine rings, and the exciton sizesare 30 and 40 atoms for indoline dyes with one and two rhodanline rings, respectively. These results serveas a good example of computer-aided design in metal-free indoline dyes for dye-sensitized solar cells.     

Exponentially fitted symmetric and symplectic DIRK methods for oscillatory Hamiltonian systems

The order conditions for modified Runge–Kutta methods are derived via the rooted trees. Symmetry and symplecticity conditions and exponential fitting conditions for modified diagonally implicit Runge–Kutta (DIRK) are considered. Three new exponentially fitted symmetric and symplectic diagonally implicit Runge–Kutta (EFSSDIRK) methods of respective second order and fourth order are constructed. Phase properties of the new methods are analyzed. The new EFSSDIRK methods are applied to several Hamiltonian problems and compared to the results obtained by the existing symplectic DIRK methods in the literature.     

Synthesis of 2,5-disubstituted 1,3,4-oxadiazoles by visible-light-mediated decarboxylation–cyclization of hydrazides and diketones

A visible-light-induced synthesis of 2,5-disubstituted 1,3,4-oxadiazoles from simple diketones and hydrazides with the assistant of the photocatalyst eosin Y catalyzed decarboxylation and cyclization under mild conditions has been discovered. The reaction tolerates a wide range of functional groups and gives a variety of valuable 1,3,4-oxadiazoles in moderate to good yields. Finally, a plausible reaction mechanism was proposed.     

The Smallest One-Realization of a Given Set III

In Zhao et al. (Electron J Combin 19: \({\sharp}\) P19, 2012), we determined the minimum number of vertices of one-realizations of a given finite set S, and constructed the corresponding mixed hypergraphs. In this paper, by finding some of their spanning sub-hypergraphs, we determine the minimum number of \({\mathcal{D}}\) -deges (resp. \({\mathcal{C}}\) -edges) of one-realizations of S. As a result, we partially solve an open problem proposed by Tuza and Voloshin (Bolyai Society Mathematical Studies, vol. 17, pp. 235–255. Springer, Berlin, 2008).     

Single-frequency polarized eye-safe all-fiber laser with peak power over kilowatt

An all-fiber, single-frequency, linearly polarized, high peak-power, pulsed laser at 1,540 nm for Doppler wind lidar is presented. This laser is composed of a single-frequency, narrow-linewidth external cavity diode laser, and multistage fiber amplifiers. A peak power of 1.08 kW and a pulse width of 500 ns at 10 kHz repetition rate are achieved, which is the highest peak power with a linewidth of 800 kHz in erbium-doped silica fiber to our knowledge. The beam quality of M ² < 1.3 and a polarization extinction ratio over 16 dB are obtained. This laser will be employed in a compact long-range coherent Doppler wind lidar.     

磁光阱中单原子荧光信号的优化及单原子的高效装载

实验中首先通过增大四极磁场梯度、提高背景真空度、缩小冷却俘获激光光束直径的方法获得了磁光阱中单原子的装载.其次,通过减小冷却光失谐量、适当增加其光强、同时使用偏振光谱锁频技术抑制冷却光噪声的方法得到了磁光阱中高信号背景比的单原子荧光信号.此外,通过实时反馈控制磁光阱四极磁场梯度的方法,在实验中实现了单原子98%的装载概率.使用Hamburg Brown-Twiss方案测量了磁光阱中的单原子在连续光激发下所辐射荧光的光子统计特性,得到二阶关联度g(2)(τ=0)=0.09.     

First-principles calculation on p-type conduction of (Sb,N) codoping in ZnO

Based on first-principles calculations, (Sb, N) codoped ZnO are investigated. We find that Sb_Zn–4N_O have lower formation energy and can form p-type conduction with smaller hole effective mass. In comparation to monodoping of Sb, Sb_Zn–4N_O complex can form better p-type conductivity than Sb_Zn–2V_Zn, which may be strongly compensated by Sb_Zn defect and result in a decrease of p-type conduction. So we inferred that (Sb, N) codoping in ZnO under O-poor condition should be a realizable candidate of p-type conduction.     

The ultra narrow-band fiber grating filter

In this paper, we propose an ultra narrow band fiber grating filter which is composed of two optical circulators and two fiber Bragg gratings (FBG). Through numerical simulation and experiment investigation, a narrow-band output spectrum with 1064 nm center wavelength and 0.017 nm bandwidth is obtained. It may find a certain application in the fields of free space optic communication, laser tuning and so on as we believe.     

Inhomogeneous optoelectronic and microstructure property distribution across the substrate of ZnO:Al films deposited by room temperature magnetron sputtering

Aluminum doped zinc oxide (ZAO) films were deposited by direct current (DC) reactive magnetron sputtering from a ZnO:Al₂O₃ (3 wt.% Al₂O₃) ceramic target at room temperature. In order to explore the inhomogeneous property distribution across the substrate, the films were deposited with varied substrate-target distances (D_s) ranging from 2 cm to 9 cm. The experimental results obtained from four-point probe, spectrophotometer, scanning electron microscope, X-ray diffractometer and Auger electronic spectrometer were analyzed to explore the nonuniform property distribution of the obtained ZAO films. The results confirmed that the films’ optoelectronic properties, crystallinity and surface morphology, etc., which were obtained from different substrate areas facing the target were remarkably different. It was revealed that the inhomogeneous property distribution was noticeably dependent on the D_s. It was also suggested that the great difference of electrical conductivity among films from different substrate areas could not be ascribed to the difference of chemical composition, but might be explained by the distinctive crystallinity correspondingly. Films from different substrate regions with distinctive electrical characteristics were either (0 0 2) or (1 1 0) textured.     

The regularity criterion of the weak solution to the 3D viscous Boussinesq equations in Besov spaces

In this paper, by using the Fourier localization technique and Bony's paraproduct decomposition, we give a regularity criterion of the weak solution to 3D viscous Boussinesq equations in Besov spaces. Copyright © 2010 John Wiley & Sons, Ltd.