SWE-SPHysics Simulation of Dam Break Flows at South-Gate Gorges Reservoir

This paper applied a Smoothed Particle Hydrodynamics (SPH) approach to solve Shallow Water Equations (SWEs) to study practical dam-break flows. The computational program is based on the open source code SWE-SPHysics, where a Monotone Upstream-centered Scheme for Conservation Laws (MUSCL) reconstruction method is used to improve the Riemann solution with Lax-Friedrichs flux. A virtual boundary particle method is applied to treat the solid boundary. The model is first tested on two benchmark collapses of water columns with the existence of downstream obstacle. Subsequently the model is applied to forecast a prototype dam-break flood, which might occur in South-Gate Gorges Reservoir area of Qinghai Province, China. It shows that the SWE-SPH modeling approach could provide a promising simulation tool for practical dam-break flows in engineering scale

Perovskite/germanium tandem: A potential high efficiency thin film solar cell design

Perovskite absorbs from ultraviolet (UV) to similar to 800 nm, and germanium covers to 1800 nm, the combination shows excellent match in terms of solar spectrum-splitting. The optical properties of CH3NH3PbI3-xCIx perovskite and single-crystalline germanium (c-Ge) tandem solar cell on a special designed substrate with triangular grating are analyzed and discussed. The finite difference time domain (FDTD) approach is used to solve the Maxwell's equations in three dimensions rigorously. By optimizing the absorption layer thickness, the current match between the top and the bottom component cells is achieved using very thin films as thin as 1500 nm. By controlling the thickness of perovskite and c-Ge to 750 nm each, high short circuit current density (J(sc)) of the tandem solar cell is achieved to as high as 23.70 mA/cm(2). The perovskite/c-Ge tandem thin film cell design is capable of a potential efficiency 24.88% based on the simulation. (C) 2016 Elsevier B.V. All rights reserved

Interactions hyaluronane-protéines : hydrolyse du hyaluronane caractérisée par la hyaluronidase et complexation non spécifique hyaluronane-protéines. Influence de la longueur de la chaîne de hyaluronane

ROUEN-BU Sciences Madrillet (765752101) / SudocSudocFranceF

Modeling of triangular-shaped substrates for light trapping in microcrystalline silicon solar cells

The influence of triangular grating used as a light trapping structure on the optical wave propagation within thin-film microcrystalline silicon (mu c-Si:H) solar cells is investigated. A finite difference time domain (FDTD) approach is used to rigorously solve the Maxwell's equations in three dimensions. We apply two parameters of mean surface roughness (S-a) and slope (k) to define triangular structure and study their influence on the absorption of mu c-Si:H. When Se and k are set to 400 nm and 1, respectively, a largest enhancement of absorption is achieved. The optimum short circuit photocurrent (J(SC) of a 1-mu m thick mu c-Si:H solar cell made on such a textured substrate can reach 27.0 mA/cm(2). The carrier generation rate in the mu c-Si:H material is also rigorously analyzed. Finally, we identify some key optical losses in mu c-Si:H solar cells and propose for further optimizing the device design. (C) 2016 Elsevier B.V. All rights reserved

Thickness Influence on Optical and Electrical Properties of Pbl(2) Films Prepared by Pulsed Laser Deposition

Lead iodide (Pbl(2)) films with a thickness from 66 to 416 nm were prepared on glass and FTO substrates by pulsed laser deposition (PLD) technique for the first time, using a KrF excimer laser. Scanning electron microscope (SEM) images revealed the surface topographical evolution and the Volmer-Weber growth mode of the films was verified. X-ray diffractometer (XRD) measurements proved the polycrystalline nature of the deposited films with preferred orientation along (001) plane. UV-Vis-NIR measurements revealed a strong influence of thickness on the optical band gaps of the films, which decrease with the increase of thickness. It was also demonstrated that the electrical resistivities in lateral and vertical directions both decrease with the increase of film thickness

MoS2/sulfur and nitrogen co-doped reduced graphene oxide nanocomposite for enhanced electrocatalytic hydrogen evolution

Cost-effective materials for electrocatalytic water splitting are key to renewable energy research. In this work, MoS2/sulfur and nitrogen co-doped reduced graphene oxide (SNG) nanocomposite was produced via a two-step hydrothermal process. The formation of nanocomposite was confirmed by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM). It is found that the MoS2/SNG nanocomposite exhibits much higher catalytic activity for the hydrogen evolution reaction (HER) relative to MoS2 and MoS2/RGO catalysts, as manifested by much larger cathodic current density with smaller overpotential of -120 mV and lower Tafel slope of 45 mV dec(-1). It is believed that the outstanding performance is attributed to the high electronic conductivity of SNG for fast charge transport. This study highlights the significance of the strong electronic coupling effect between the MoS2 and SNG in the enhancement of HER electrocatalytic activity. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Band alignment of TiO2/FTO interface determined by X-ray photoelectron spectroscopy: Effect of annealing

The energy band alignment between pulsed-laser-deposited TiO2 and FTO was firstly characterized using high-resolution X-ray photoelectron spectroscopy. A valence band offset (VBO) of 0.61 eV and a conduction band offset (CBO) of 0.29 eV were obtained across the TiO2/FTO heterointerface. With annealing process, the VBO and CBO across the heterointerface were found to be -0.16 eV and 1.06 eV, respectively, with the alignment transforming from type-I to type-II. The difference in the band alignment is believed to be dominated by the core level down-shift of the FTO substrate, which is a result of the oxidation of Sn. Current-voltage test has verified that the band alignment has a significant effect on the current transport of the heterojunction. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

A novel multiple training-scale dynamic adaptive cuckoo search optimized long short-term memory neural network and multi-dimensional health indicators acquisition strategy for whole life cycle health evaluation of lithium-ion batteries.

State of health evaluation of lithium-ion batteries has become a significant research direction in related fields attributed to the crucial impact on the reliability and safety of electric vehicles. In this research, a dynamic adaptive cuckoo search optimized long short-term memory neural network algorithm is proposed. The aging mechanism of the battery is described effectively by extracting and selecting high correlation health indicators including voltage, current, charging time, etc. A dynamic adaptive strategy is introduced to the cuckoo search algorithm to stabilize the step size and improve the global search ability. The hyperparameter optimization and noise filtering problems of the long short-term memory model are solved and the accuracy of the algorithm is improved by taking advantage of the established dynamic adaptive cuckoo search algorithm. The accuracy and effectiveness of the proposed method are verified based on the seven groups of battery aging datasets from the National Aeronautics and Space Administration and the University of Maryland. Compared with the long short-term memory and convolutional neural network long short-term memory, the mean absolute error of the results obtained by the proposed algorithm is kept under 2%, the root mean square error is less than 3%, and the average absolute percentage error is less than 3%. The results indicate the algorithm has better fitting performance, stronger robustness, and generality

2D WS2 nanosheet supported Pt nanoparticles for enhanced hydrogen evolution reaction

By taking advantage of large specific surface area and large number of reaction sites of the 2D WS2 nanosheet (NS), we developed a simple adsorption-photoreduction method to load Pt nanoparticles (NPs) on the NS carrier. The WS2 NSs were soaked in KPtCl4 solution for sufficient amount of time to ensure the adsorption equilibrium of the Pt ions on the WS2 NS substrate. Upon photolysis and H-2 post-treatment, uniformly dispersed Pt NPs (similar to 2 nm in size) were harvested. The hybrid structure containing OD Pt NPs and 2D WS2 thin-layers showed distinctly enhanced electrocatalytic activity for hydrogen evolution reaction (HER) with the overpotential at a current density of 10 mA cm(-2) reduced to 80 mV compared with commercial Pt/C electrode. The synergetic effect of OD and 2D structures may encourage designing new catalysts systems for special application. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved