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Today there are new interests in using metallic lithium as anode materials in lithium batteries because of its extremely large theoretical specific capacity. However, the low cycle efficiency and the lithium dendrite formation during repeated charge/discharge cycles hinder the practical application of metallic lithium anodes. Herein, we report a distinctive ZrO 2 /POSS multilayer deposited on PE separators by a simple layer-by-layer (LbL) self-assembly process to enable excellent rate capability and cycle life of lithium metal batteries. The ZrO 2 /POSS multilayer on PE separators weakens the solvation effect of lithium ions and significantly enhances the electrolyte uptake of separators, which is responsible for the enhanced ionic conductivity and Li + transference number, as well as the improved Li/electrolyte interfacial stability. These advantageous characteristics of the resulting PE separators effectively decrease the electrode polarization and protect lithium metal anodes against lithium dendrites formation during repeated charge/discharge cycles, endowing LiCoO 2 /Li unit cells with both excellent electrochemical performance and high safety. The fundamental understanding on the effects of the micro/nano structures and properties of separators on the important electrochemistry processes at electrode/electrolyte interface of battery systems may lead to new approaches to tackle the intrinsic problems of Li metal anodes for energy storage applications. [ABSTRACT FROM AUTHOR]

Abstract: Cu2+-doped TiO2 film on stainless steel substrates was prepared using sol–gel method. Based on XRD and SEM analysis results, the as-prepared film was mainly in anatase phase. The film was smooth and the thickness of the film was about 2μm. The UV–vis absorption of Cu2+-doped TiO2 was extended to visible range, which is favorable for the utilization of solar light. The photoelectrochemical properties of the samples were investigated via electrochemical impedance spectrum (EIS). The EIS plots demonstrated that the Cu2+-doped TiO2 can be excited under visible light irradiation and the photo-generated electron–hole pairs can be separated efficiently by applying an external bias. The degradation experiments for methylene blue and methyl orange in different processes showed that the photo-response range of TiO2 could be extended by doping Cu2+ ion and the photocatalytic activity of TiO2 could be enhanced with the help of a forward bias. [Copyright &y& Elsevier]

Abstract: While coal seam is being mined, an annular fissure circle with gas accumulation will be formed in the fissure zone as a result of desorption, dissipation and permeation of gas in the goaf area and overlying strata due to fissures from rock caving and mitigation in the roof. The methods for computation of spatial locations of the fissure circle are researched in this paper. Based on these methods, gas drainage technique for the fissure zone is optimized. By applying drill hole returning water method of variables, the height of caving zone that most affects the drainage effects of inclined high dip drill hole was measured on the site. Due to the consistency of the expected height with the computed height of caving lines at different positions, the correctness of the theoretical computation method is further validated. Meanwhile, the parameters of the inclined high dip drill hole at #3311 working face of Hexi Coal Mine are determined by a case study. [Copyright &y& Elsevier]

Designing large neural network models targeting high accuracy and low sample number requirement is an important task in accelerating airfoil ice accretion calculation. Both convolutional neural network and Transformer are potential large-scale architectures for icing image generation. In this study, FSRN (fused super-resolution network) and ViT (Vision Transformer) are designed and applied to predict icing images with complex shapes. The novelty of FSRN lies in dividing the training process into main feature generation and detail information processing, and three branches of SR (super-resolution) networks are applied for multi-inputs and fused to generate icing images. The core part of ViT is the large-scale attention structure which is proven to be powerful in learning features. Both 7-dimensional icing condition vectors and the airfoil image are set as inputs to predict 136×136 icing images, and FocalLoss is chosen as the loss function. FSRN achieves determination coefficients of 0.974 and 0.958 respectively while ViT achieves 0.967 and 0.953 in two validation data sets. FSRN demonstrated greater potential in reducing sample number compared to ViT and MLP (multilayer perceptron). [ABSTRACT FROM AUTHOR]

Poor stability of lithium metal anodes in liquid electrolytes hinders its practical application in rechargeable batteries with very high energy density. Herein, we present an approach to tackle the intrinsic problems of Li metal anodes from the standpoint of separators. By a facile and versatile method based on mussel-inspired surface chemistry, a hybrid polydopamine/octaammonium POSS (PDA/POSS) coating was spontaneously formed on the surface of PE separators through the self-polymerization and strong adhesion feature of dopamine. This ultrathin PDA/POSS coating endows PE separators with different surface characteristics while keeping its microporous structure almost unchanged. The altered surface characteristics influence the separator/electrolyte interaction, and lead to remarkable enhanced ionic conductivity (from 0.36 mS cm −1 to 0.45 mS cm −1 ) and Li + ion transference number (from 0.37 to 0.47) of PE separators as well as the improved stability of lithium/electrolyte interface, which effectively decreases the electrode polarization and suppresses the lithium dendrites formation, contributing to superior C-rates capability and cycling performance of cells. [ABSTRACT FROM AUTHOR]

The objective of this work is to gain deeper insight into behavior of p-type DSSCs, paying special attention to photoelectric properties of Li-doped NiO photoelectrode, and studying their effect on interfacial photoelectrochemical processes under illumination and device performance. Here we find that Li-doped NiO photoelectrodes show higher charge carrier densities, down-shift of valence band and narrowing trap energy distribution. Furthermore, the performance enhancement of p-type DSSCs is observed for the Li-doped NiO photoelectrodes with respect to the unmodified ones. These improvement is found to arise from more rapid hole transport combined with reduced recombination, contributing to improved hole collection. With regard to interfacial carriers transfer process, electrochemical impedance spectroscopy (EIS), intensity-modulated photovoltage spectroscopy (IMPS) and ultra-violet photoemission spectra (UPS) provide evidence that the decreased recombination of Li-doped NiO DSSCs is attributed to the downward shift of valence band, which increases energy barrier of interface recombination. Another reason results in narrowing trap energy distribution of Li-doped NiO photoelectrode, which can weaken energy overlap with the LUMO level of dye, and subsequently the recombination path of hole back transfer to dye is hindered. These findings suggest that it will be important to carefully optimize band edge alignment and trap states distribution of p-type oxide semiconductors film to further improve the efficiency of p-DSSCs. [ABSTRACT FROM AUTHOR]

Acetyl acetone and its derivatives, 3-butyl-2,4-pentanedione and 3-phenyl-2, 4-pentanedione are investigated as co-adsorbents of photoelectrodes for dye-sensitized solar cells (DSSC). The DSSC based on 3-phenyl-2,4-pentanedione co-adsorbent shows the best photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 67.3%, a short-circuit photocurrent density (J SC ) of 15.73 mA cm 2 , an open-circuit photo-voltage (V OC ) of 0.74 V and a fill factor (FF) of 0.69, corresponding to an overall conversion efficiency of 8.07% under the standard global AM 1.5 solar light condition. Electrochemical impedance (EIS) data and open-circuit voltage decay (OCVD) data indicate that the electron lifetime is improved by co-adsorption of 3-phenyl-2,4-pentanedione, it is associated with the 3-phenyl-2,4-pentanedione co-adsorbent forms a protect layer of TiO 2 which can inhibit the electron recombination efficiently. The results confirm that the acetyl acetone-typed co-adsorbents with less effect on the adsorption of dye, more hydrophobic structure and stronger electron donating ability, such as 3-phenyl-2,4-pentanedione, can improve the performance of DSSC. [ABSTRACT FROM AUTHOR]

Highlights: [•] W6+-doped TiO2 nanocrystal colloids were prepared by hydrothermal methods. [•] The properties of TiO2 nanocrystal colloids can be tuned by tungsten doping. [•] W6+-doped TiO2 nanocrystal colloids show higher stability and dispersity. [•] W6+-doped TiO2 nanocrystal colloids show higher photocatalytic activity. [ABSTRACT FROM AUTHOR]

Highlights: [•] TiO2 nanoparticles were decorated on ZnO surface by tetrabutyl titanate (TBOT). [•] The simple method allows an easy tune over the TiO2 structure on ZnO surface. [•] The influence of TiO2 modification on electron collection was discussed. [ABSTRACT FROM AUTHOR]

Abstract: The effects of K-substitution at La-site of La1−x K x Co0.3Fe0.7O3-δ perovskite on its structure and humidity sensing properties were studied in detail. The XRD, SEM-EDS, N2 adsorption–desorption measurements (BET), ICP-AES and XPS were used to characterize the microstructure of La1−x K x Co0.3Fe0.7O3−δ perovskite. The results show that the partial substitution of K at La-site has no obvious effect on the crystal phase, morphology and surface area of samples, but leads to the increased oxygen vacancies and surface enriched K+. The sensitivity of humidity sensor based on all samples was evaluated by measuring the impedance response to the humidity changes. The partial substitution of K at La-site significantly enhanced the humidity sensitivity of La1−x K x Co0.3Fe0.7O3−δ perovskite at low relative humidity (RH). By correlating the structure of material with its sensing properties, the probable reasons that lead to the remarkable sensitivity enhancement of the K-substitution samples compared with the unsubstituted sample (LaCo0.3Fe0.7O3−δ ) were given; moreover, the sensing mechanism was also discussed by the complex impedance spectra in detail. [Copyright &y& Elsevier]

Abstract: The Sn4+ doped anatase TiO2 nanocrystals with various amounts of dopant Sn4+ ions were prepared from peroxo-metal-complex precursor by solvothermal method and characterized by XRD, TEM, HRTEM, XPS, ICP-AES and UV–vis spectrophotometer. The experimental results indicated that the dopant Sn4+ substituted Ti4+ in the lattice of TiO2, which reflected in the lattice expansion in both a- and c-direction and change of the binding energy. All the Sn4+ doped TiO2 nanocrystal samples appeared to be anatase evenly with dopant level up to 10mol%. The effect of dopant Sn4+ ions and reaction solvents on physicochemical properties of the obtained Sn4+ doped anatase TiO2 nanocrystals had been discussed. In addition, the growth mechanism and microstructure evolution of Sn4+ doped anatase TiO2 nanocrystals had been suggested. The photocatalytic activity of the Sn4+ doped anatase TiO2 nanocrystals was tested by the degradation of phenol. Compared with the undoped TiO2 sample, the enhanced photocatalytic activity of the Sn4+ doped anatase TiO2 nanocrystals could be attributed to modification of the optical properties and surface state by doping the optimum concentration of Sn4+ ions. [Copyright &y& Elsevier]

Abstract: The preparation of Ti1−x Sn x O2 nanocrystal colloids from peroxo-metal precursor by hydrothermal method was reported in this work. The obtained materials were investigated by means of XRD, Raman, TEM, XPS, ICP-AES, N2 adsorption–desorption measurements (BET), PL and UV–vis spectroscopies technology. Photocatalytic degradation of phenol was studied under UV illumination. The results indicated that Ti1−x Sn x O2 nanocrystal colloids were obtained in the nanometer scale (less than 10nm) and the crystallite size was smaller than pure TiO2. Anatase phase, mixture phase (anatase and rutile) and rutile phase of Sn-doped TiO2 samples were formed, when x <0.04, 0.04< x <0.06 and x ≥0.06, respectively. The Sn4+ dopants presented substitution Ti4+ into the lattice of TiO2 alongside increasing the surface oxygen vacancies and the surface hydroxyl groups. Regarding photocatalytic activity, Sn-doped TiO2 samples (TiSn3) were nearly four times higher than undoped samples. This obvious beneficial effect could be attributed to high surface area, optimal crystalline phase and surface state modifications. [ABSTRACT FROM AUTHOR]

In the preliminary aerodynamic design phase of transonic wing, inverse design of supercritical airfoils plays an important role in acquiring practical results. However, traditional inverse design approach in transonic regime highly dependents on the manual design experience and physical model simulation, which is time consuming and poses a challenge for its applications in engineering problems. In order to relieve these drawbacks, a novel method is proposed for inverse design of supercritical airfoils based on Wasserstein generative adversarial network (WGAN), genetic algorithm (GA) and deep convolutional neural network (DCNN). This method consists of three stages. First, design characteristics of transonic pressure coefficient (CP) distribution in physics are well captured and imitated by WGAN. Then, GA is used to select task-oriented CP via adjusting controllable latent variables in generator of WGAN. Next, physical-existing CP selected by GA is recovered to corresponding airfoil by DCNN with high efficiency and accuracy. Cases using the dataset sampled based on RAE2822 airfoil are carried out to show effectiveness of submodules involved. Finally, design performance of proposed multistage method is further verified by specific design goals. Test cases indicate that selected CP by GA according to the aerodynamic design criteria can be accurately reflected on inverse designed airfoils, which are confirmed by well agreements between high-fidelity simulation result and selected CP. The proposed method is a promising design approach that can quickly achieve optimal airfoils without significant loss of accuracy. [ABSTRACT FROM AUTHOR]

• Heat transfer distributions, mean flow fields and turbulent flow structures of surface vortex structures are obtained. • DES results are compared with the corresponding RANS and experimental results. • Heat transfer enhancement mechanisms of surface vortex generators have been revealed. • The micro V rib-dimple significantly reduces the dead-air zone in the dimple. Turbulent flow and heat transfer characteristics in the channels with surface vortex structures of micro V-shaped ribs, dimples, and their hybrid structures have been investigated by carrying out delayed detached eddy simulations (DDES) at the Reynolds number of 50,500. It is found that, for the micro V-shaped rib, lower turbulent mixing is produced behind the leeward rib region, while the stronger longitudinal vortex pairs induced by the V-shaped ribs enhance the convective transport of heat. For the dimple, the shed vortices and the shear-layer vortices increase the near-wall turbulent mixing. The complex secondary flows induced by the flow separation, attachment and ejection increase the convective transport of heat. However, the flow separation produces a dead-air zone limiting the further increase of heat transfer enhancement. For the micro V-shaped rib-dimple hybrid structure, the strong downwash flow induced by the micro V rib breaks the recirculation zone inside the downstream dimple and the dimple here works as a vortex amplifier, which produces much stronger longitudinal vortex pairs. This process enhances both the turbulent mixing and convective transport of heat. Therefore, the micro V-shaped rib-dimple hybrid structure provides even more pronounced heat transfer enhancement. [ABSTRACT FROM AUTHOR]

Anode materials with large capacity have a growing application due to the booming electric vehicle and energy storage market. However, the low initial Coulombic efficiency (ICE) and poor cycle stability hinder their commercial development. Herein, we investigate the effective and convenient method of preparing Li x Sn-Li 2 O–LiF/reduced graphene oxide (Li x Sn-Li 2 O–LiF/RGO, Li-GFTO) composite anode material with large capacity and high ICE. Firstly, the highly-dispersed fluorine-doped tin oxide and reduced graphene oxide (F–SnO 2 /RGO, GFTO) composite is in-situ synthesized by one-pot reflux method. The fluorine-doped SnO 2 nanocrystals are uniformly anchored on graphene sheets. Secondly, the F–SnO 2 /RGO was lithiated by reacting with the lithium dissolved in the solution of biphenyl and 1,2-dimethoxyethane to get Li x Sn-Li 2 O–LiF/RGO composite. The Li 2 O and LiF will be formed and prevent the diffusion and coarsening of Sn and Li x Sn during cycling. Used as the anode material, the ICE of the Li x Sn-Li 2 O–LiF/RGO composite is as high as 97%. The composite anode material also shows high cycling stability. The residual capacity is as high as 992 mAhg−1 at 0.1 Ag-1 after 100 cycles, and the charge capacity retention is 99%. Most of all, the mild preparation condition promotes the mass production and practical application of tin-lithium alloy based composite anode materials. Image 1 • Li x Sn-Li 2 O–LiF/RGO composite was obtained by the lithiation of F–SnO 2 /RGO. • Initial Coulombic efficiency of Li x Sn-Li 2 O–LiF/RGO composite is as high as 97%. • The residual capacity is as high as 992 mAhg−1 after 100 cycles. [ABSTRACT FROM AUTHOR]