Solution processable reduced graphene oxide decorated ATO electrode for organic solar cells

A novel concept based on the use of solutions containing already qualified crystalline antimony-doped tin oxide SnO₂:Sb (ATO) nanoparticles has been developed. ATO nanoparticles are decorated by reduced graphene oxide (rGO) through a hydrothermal synthesis method. The electrical and optical properties of the graphene oxide films are investigated systematically. The sheet resistance (R _□) of the ATO–rGO films decreases with the increase in the rGO content in the precursor solution. The R _□ can be decreased after the ATO–rGO films annealing in the air for 1 h and can be further decreased by depositing Au on the surface of the films. The optimum property of the ATO–rGO film shows that the R _□ is 80 Ω/□ and the transmittance is about 70 %. The ATO–rGO films are used as the anode of the organic solar cells. The anode film impact on the performance of the devices is studied. Finally, the power conversion efficiency (PCE) of the device based on the poly-(3-hexylthiophene): [6, 6]-phenyl C61-butyric acid methyl ester (PCBM) blended is 1.85 %, and the PCE of the device based on the poly-benzo[1,2-b:4,5-b′] dithio-phene thieno[3,4-b] thiophene:PCBM blended is 3.4 %.     

多狭缝空间滤波假彩色编码

利用空间滤波合成狭缝彩虹全息技术对二维透射物进行假彩色编码,当参考光以不同的方向传播时,记录二维透射物的不同空间频谱所对应的物像,全息图在白光再现时将透镜平移就呈现不同颜色全息效果图。     

High-speed visualization and PIV measurements of cavitating flows around a semi-circular leading-edge flat plate and NACA0015 hydrofoil

Cavitating flows around a flat plate with semi-circular leading edge and a NACA0015 hydrofoil at attack angles ranging from 0° to 9° and with varying cavitation number are investigated using high-speed-imaging visualization (HIV) and particle-imaging velocimetry (PIV). Several known types of cavitation common to both foils, but also some different patterns, were observed. At small angles of incidence (less than 3°), cavitation on the plate begins in the form of a streak array (bubble-band) whereas on the hydrofoil as traveling bubbles. For the regimes with developed cavitation on the NACA0015 hydrofoil, the scattered and discontinuous bubble streaks branch and grow but subsequently merge into bubble clouds forming a remarkably regular lattice pattern. Once the incidence angle increased to 9°, the cavitation on the hydrofoil changed to a streaky pattern like that on the plate at small attack angles, whereas the regime on the plate showed no significant changes. The PIV method proved to be usable for measuring the instantaneous velocity also in the gas–vapor phase, albeit with reduced accuracy that was evaluated and accounted for on the basis of the effective (validation-surviving) number of imaging samples. The time-averaged velocity and turbulence moments show that the incipience of cavitation is governed by the development of the carrier-fluid flow around the foil leading edges, but the subsequent flow pattern depends strongly on the cavitation regime displaying markedly different distributions compared to the non-cavitating case. The main cavitation parameters: the maximum cavity length, the cloud cavity streamwise dimensions and the cloud shedding Strouhal number are analyzed and presented in function of the cavitation number and the attack angle in different scaling. The measurements confirm qualitatively the trends reported in the literature, but show also some quantitative differences, notably between the two foils considered.     

Numerical simulation of the fluid–structure interaction in a tube array under cross flow at moderate and high Reynolds number

The unsteady loads in a tube bundle are studied at moderate and high Reynolds number by means of URANS and hybrid (DDES) modelling. The onset of fluid-elastic instability is analysed for different structural parameters, Scruton number and reduced velocity. The simulations have been carried out with the code NSMB (Navier–Stokes Multi Block) by using turbulence modelling methods URANS and DDES (Delayed Detached Eddy Simulation). The CEA-DIVA configuration is considered for the cylinders array for an inter-tube Reynolds number 60 000. The study is carried out for a configuration of (4×5) cylinders in static conditions as well as for the vertical free motion of one of the central cylinders in one DOF (Degree Of Freedom).The inter-tube Reynolds number is 60 000. It is found that this cylinder spontaneously displays an oscillatory motion which first corresponds to Vortex Induced Vibration (VIV), associated to a lock-in mechanism for low values of the reduced velocity and secondly develops Movement Induced Vibration, MIV, for higher values of the reduced velocity. The variation of the cylinder׳s oscillations frequency, of the unsteady loads and the structure׳s displacement are studied as a function of the reduced velocity for low and high values of the Scruton number. The increase of the phase-lag between the forces and the displacement is predicted and discussed for different Scruton number values and reduced velocities.     

Removal of field-collected Microcystis aeruginosa in pilot-scale by a jet pump cavitation reactor

Hydrodynamic cavitation has been investigated extensively in the field of water treatment in the last decade and a well-designed hydrodynamic cavitation reactor is critical to the efficient removal of algal and large-scale application. In this paper, a jet pump cavitation reactor (JPCR) is developed for the removal of cyanobacteria Microcystis aeruginos in a pilot scale. The results demonstrate that the photosynthetic activity of M. aeruginosa is greatly inhibited immediately after treatment in the JPCR, and the growth is also hindered after 3 days culture. Moreover, a high cell disruptions of M. aeruginosa is detected after treated by JPCR. The release of chlorophyll-a indicates that the JPCR caused serious rupture to M. aeruginosa cells. The plausible cell disruption mechanisms are proposed in accordance with a fluorescence microscope and scanning electron microscope. Then, the optimization of cell disruption efficiency is also investigated for various operating conditions. The results showed that the algal cell disruption efficiency is improved at higher inlet pressure and the cavitation stage between the unstable limited operation cavitation stage and stable limited operation cavitation stage. The effect and optimization of JPCR on algal reduction are highlighted. The results of the study promote the application of hydrodynamic cavitation on algal removal and provide strong support for JPCR application in algal removal.     

Tunable electronic properties of GaS-SnS2 heterostructure by strain and electric field

Vertically stacked heterostructures have received extensive attention because of their tunable electronic structures and outstanding optical properties. In this work, we study the structural, electronic, and optical properties of vertically stacked GaS-SnS₂ heterostructure under the frame of density functional theory. We find that the stacked GaS-SnS₂ heterostructure is a semiconductor with a suitable indirect band gap of 1.82 eV, exhibiting a type-II band alignment for easily separating the photo-generated carriers. The electronic properties of GaS-SnS₂ heterostructure can be effectively tuned by an external strain and electric field. The optical absorption of GaS-SnS₂ heterostructure is more enhanced than those of the GaS monolayer and SnS₂ monolayer in the visible light region. Our results suggest that the GaS-SnS₂ heterostructure is a promising candidate for the photocatalyst and photoelectronic devices in the visible light region.     

Reactivity of polyhydroxyalkyl-heterocycles towards Lewis acids

We report the reactivity of different polyhydroxyalkyl-heterocycles towards ceric ammonium nitrate (CAN) and ferric chloride. The behaviour of 2-methyl-5-(tetritol-1-yl)-pyrroles and -furans is different towards CAN oxidation. Pyrroles afford 2,5-diformylheterocycles, while furans give access to 1,4-dicarbonyl compounds containing three stereogenic centres. Ferric chloride promotes an intramolecular C-arylation reaction on O-benzylated-polyhydroxyalkyl furans, yielding an isochroman moiety, which is the basic skeleton of a variety of natural products.     

具有AUMD性质的复Banach空间的某些特征

本应用解析鞅的一类特殊的不等式给出了具有AUMD性质的复Banach空间的某些特征。