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Aiming at the problems of difficult detection, low recognition efficiency and strong subjectivity of foam flotation dosing state, a flotation condition recognition method of nuclear random-weight neural networks(K-RVFLNs)combining multi-scale CNN characteristics and improved local binary patterns(LBP)calculation methods is proposed.Firstly, non-downsampling Shearlet multi-scale decomposition(NSST)is performed on the bubble flotation image, the original image is decomposed into different frequency scales, and a multi-channel CNN network is designed to extract features from the multi-scale image.By improving the LBP algorithm to extract features as a supplement, the image features extracted by CNN are fused with LBP features; Finally, the classification decision is made by mapping to a higher dimensional space by the nuclear stochastic right neural network, and the accurate identification of flotation dosing state is realized.Experimental results show that the method of multi-scale CNN and LBP-TOP feature fusion is 5.34 % higher than that of the traditional LBP algorithm, 3.76 % higher than that of single CNN feature recognition method, and the accuracy of flotation condition classification is as high as 96.38 % in combination with K-RVFLNs, and the recognition accuracy and stability are greatly improved compared with the existing methods, and this method reduces manual intervention and is conducive to improving production efficiency.

Converting CO2 to value‐added chemicals, e. g., CH3OH, is highly desirable in terms of the carbon cycling while reducing CO2 emission from fossil fuel combustion. Cu‐based nanocatalysts are among the most efficient for selective CO2‐to‐CH3OH transformation; this conversion, however, suffers from low reactivity especially in the thermodynamically favored low temperature range. We herein report ultrasmall copper (Cu) nanocatalysts supported on crystalline, mesoporous zinc oxide nanoplate (Cu@mZnO) with notable activity and selectivity of CO2‐to‐CH3OH in the low temperature range of 200–250 °C. Cu@mZnO nanoplates are prepared based on the crystal‐crystal transition of mixed Cu and Zn basic carbonates to mesoporous metal oxides and subsequent hydrogen reduction. Under the nanoconfinement of mesopores in crystalline ZnO frameworks, ultrasmall Cu nanoparticles with an average diameter of 2.5 nm are produced. Cu@mZnO catalysts have a peak CH3OH formation rate of 1.13 mol h−1 per 1 kg under ambient pressure at 246 °C, about 25 °C lower as compared to that of the benchmark catalyst of Cu−Zn−Al oxides. Our new synthetic strategy sheds some valuable insights into the design of porous catalysts for the important conversion of CO2‐to‐CH3OH. [ABSTRACT FROM AUTHOR]

Due to the surface inhomogeneity of the solid supports, direct growth of uniform bimetallic nanoparticles (NPs) with controllable structure and size thereon is particularly challenging. Herein, a surface‐confinement strategy is reported to directly prepare ultrafine bimetallic PtM NPs (MFe, Cu, and Co) with structure of core‐shell or intermetallic compounds on an N functionalized carbon support (NC). It is found that the N species of NC support can atomically disperse metal cations of precursors, which largely renders uniform nucleation and growth of bimetallic NPs and fine structure modulation of them. In another regard, metal transfer is confined to a narrow region on NC via N‐mediation, hence greatly favoring localized particle growth and formation of ultrafine bimetallic NPs. Remarkably, the ultrafine 3.1 ± 0.7 nm intermetallic Pt3Fe NPs on NC displayed excellent catalytic activity and durability toward electrochemical hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

To address the problems of difficult online monitoring, low recognition efficiency and the subjectivity of work condition identification in mineral flotation processes, a foam flotation performance state recognition method is developed to improve the issues mentioned above. This method combines multi-dimensional CNN (convolutional neural networks) characteristics and improved LBP (local binary patterns) characteristics. We have divided the foam flotation conditions into six categories. First, the multi-directional and multi-scale selectivity and anisotropy of nonsubsampled shearlet transform (NSST) are used to decompose the flotation foam images at multiple frequency scales, and a multi-channel CNN network is designed to extract static features from the images at different frequencies. Then, the flotation video image sequences are rotated and dynamic features are extracted by the LBP-TOP (local binary patterns from three orthogonal planes), and the CNN-extracted static picture features are fused with the LBP dynamic video features. Finally, classification decisions are made by a PSO-RVFLNs (particle swarm optimization-random vector functional link networks) algorithm to accurately identify the foam flotation performance states. Experimental results show that the detection accuracy of the new method is significantly improved by 4.97% and 6.55%, respectively, compared to the single CNN algorithm and the traditional LBP algorithm, respectively. The accuracy of flotation performance state classification was as high as 95.17%, and the method reduced manual intervention, thus improving production efficiency. [ABSTRACT FROM AUTHOR]

It is extremely challenging to controllably synthesize rare earth‐containing nanoalloys due to the ultralow standard reduction potential of rare earth metals. Here, a surface‐confined strategy to prepare ultrafine Pt‐rare earth nanoalloys on a series of N‐functionalized supports is reported. It proves that by surface N‐metal coordination, the metal cations of precursors are atomically dispersed on support, which greatly favors uniform nucleation and growth of particles upon reduction. Moreover, the moderate metal transfer barrier from N ensures particle growth in a confined region to form ultrafine nanoalloys. Using this method, ultrafine PtLa, PtY, and PtDy nanoalloys are prepared on N‐functionalized supports such as carbon, zeolite, and Al2O3. Notably, the PtLa nanoalloys on N‐functionalized zeolite show superior activity and durability for propane oxidation. The strategy is expected to provide guidelines for preparing highly efficient rare earth‐containing nanoalloys for catalysis applications. [ABSTRACT FROM AUTHOR]

Bimetallic nanoalloys have attracted great research interest in the past decades by virtue of their tunable metal‐metal synergies. The preparation of well‐defined bimetallic nanoalloys largely relies on the use of capping ligands, which brings a great challenge to utilize the surface‐accessible active sites and/or tailor bimetallic‐support interactions. In the current paper, surface‐clean, thermally stable and monodisperse PdAu nanoalloys confined in mesoporous TiO2 (PdAu@mTiO2) were prepared using evaporation‐induced self‐assembly with two colloidal templates. The hydrogenation activity of PdAu@mTiO2 was demonstrated to be approximately 6 times higher than that of PdAu nanoalloys supported on mesoporous silica due to the bimetallic‐support interactions. Our method is expected to open up new opportunities to synthesize ligand‐free and stable bimetallic nanoalloys with tailored bimetallic‐support interactions for highly efficient catalysis. [ABSTRACT FROM AUTHOR]

Lithium-oxygen batteries have attracted considerable interest in the past a few years, because they have higher theoretical specific energy than Li-ion batteries. However, the available energy densities of the Li-O2 batteries are much less than expected. It is particularly urgent to find catalyst with high activity. Herein, a series of Co3O4 with different morphologies (ordered two-dimensional porous nanosheets, flowerlike and cuboidlike) were successfully prepared through facile hydrothermal and calcination methods. Ordered two-dimensional Co3O4 nanosheets show the best cycling stability. Detailed experimental results reveal that the superiority of the unique two-dimensional uniform porous structures is vital for Li-O2 batteries cathode catalysts. Due to the ordered structures with high surface areas and active sites, the catalysts indicate a high specific discharge capacity of about 10,417 mAh/g at a current density of 200 mA/g, and steadily cycle for more than 50 times with a limited capacity of 1,000 mAh/g. [ABSTRACT FROM AUTHOR]

We report a highly efficient Pd/Ni(OH) catalyst loaded with ultra-low levels of palladium (50 ppm Pd by mass) for the selective hydrogenation of acetylene to ethylene. The turnover frequency for acetylene conversion over the 0.005% Pd/Ni(OH) catalyst is twice that of the equivalent 0.8% Pd/Ni(OH) catalyst. Notably, an acetylene-to-ethylene selectivity of 80% was achieved over a wide range of temperatures. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy was used to reveal the atomically dispersed nature of palladium in the 0.005% Pd/Ni(OH) catalyst. The excellent selectivity of this catalyst is attributed to its atomically dispersed Pd sites, while the abundant hydroxyl groups of the support significantly enhance the acetylene conversion activity. This work opens up innovative opportunities for new types of highly efficient catalysts with trace noble-metal loadings for a wide variety of reactions. [ABSTRACT FROM AUTHOR]

A new coordination polymer, namely [Cd2(tdc)2(bpp)(DMA)]n(1, H2tdc = 2, 5-thiophenedicarboxylic acid, bpp = 1,3-bis(4-pyridyl)propane, DMA = N,N-dimethylacetamide), has been successfully obtainedviasolvothermal reactions of Cd(NO3)2, H2tdc, and bpp. Single-crystal X-ray structural analysis reveals that compound1is a twofold interpenetrated three-dimensional (3D) framework with four-connectedpcutopology. Moreover, the luminescent properties and thermal stability of1were also studied in this work. [ABSTRACT FROM PUBLISHER]

A new Zn(II) coordination polymer, namely [Zn2(datrz)2(nic)2]n(1Hdatrz = 3,5-diamino-1,2,4-triazole, Hnic = nicotinic acid), has been obtained through solvothermal reactions of Zn(NO3)2, Hdatrz and Hnic. The crystal crystallizes in triclinicP-1 space group,a= 9.4379(6) Å,b= 10.0180(6) Å,c= 11.9812(8) Å, α = 73.711(6)°,b= 72.646(6)°, γ = 88.515(5)°,Z= 2. The title compound features a 2D layer structure, which further extends into a 3D supramolecular framework via intermolecular hydrogen bonds. In addition, the luminescent properties of1were also investigated at room temperature. [ABSTRACT FROM AUTHOR]

Arsenopyrite is a common arsenic-containing mineral that is often closely associated with sulfide minerals, such as pyrite, chalcopyrite, pyrrhotite, galena, and sphalerite, and with precious metals, such as gold and silver. The selective inhibition of arsenopyrite is an important method used to reduce the arsenic content of processed products, the cost of arsenic removal in metallurgical processes, and its impact on the environment. In this study, we discovered a chemical sodium, m-nitrobenzoate (m-NBO), that can effectively inhibit the flotation behaviors of arsenopyrite via sodium butyl xanthate (NaBX), and these effects were studied by flotation experiments. The results showed that, using NaBX as a collector, arsenopyrite had good floatability under acidic conditions, but the floatability decreased under alkaline conditions. Furthermore, the organic inhibitor m-NBO had a significant inhibitory effect on arsenopyrite under alkaline conditions. In addition, the adsorption between m-NBO and NaBX was competitive, and a hydrophilic layer formed on the surface of arsenopyrite. The passivation film prevents dixanthogen from being adsorbed on the surface of the mineral. Due to the effect of m-NBO on arsenopyrite, the redox potential and oxide content of the arsenopyrite surface increased, the hydrophobicity of the arsenopyrite surface was reduced, and the flotation of arsenopyrite was inhibited. These results provide options for separating multimetal sulfide minerals and arsenic-containing minerals. [ABSTRACT FROM AUTHOR]

AbstractBacterial Mn(II) oxidation is believed to play a dominant role in accelerating the rate of Mn biomineralization in nature. Commonly, bacteria employ two ways involving Mn(II) oxidases and reactive oxygen species to oxidize Mn(II). In this study, a new strategy for bacterial Mn(II) oxidation involving the pyocyanin, a greenish blue phenazine pigment from Pseudomonas aeruginosa, was discovered. To begin with, a bacterial strain L3 was isolated from soils and identified as Pseudomonas aeruginosa, which exhibited the ability of Mn(II) oxidation. Next, the pyocyanin was purified from strain L3 cultures and proven to be involved in Mn(II) oxidation. Particularly, the oxidation of Mn(II) by pyocyanin was dependent on its ambient pH. In comparison with pH of 5 and 7, pyocyanin (the initial value of OD387 was 0.56 at pH of 2) showed a stronger capability of oxidizing Mn(II) at pH of 9, reaching 144.03 μg L−1 of Mn oxides after 108 h of Mn(II) oxidation, while pyocyanin ultimately produced 43.81 μg L−1 at pH of 7 and 3.32 μg L−1 at pH of 5, respectively. Further, strain L3 cultures were fractionated into three parts, i.e., the cell culture solution, fermentation supernatant, and cell suspension, and the Mn(II)-oxidizing activity was found to be distributed in the cell culture solution and fermentation supernatant, as evidenced by the formation of blackish glossy Mn oxides. Specifically, in the first half, the rate of Mn(II) oxidation by the fermentation supernatant was higher than that by the cell culture solution, whereas in the second half, the cell culture solution showed the much higher Mn(II)-oxidizing activity compared to the fermentation supernatant. Last but not least, the collective results from mineral characterization demonstrated that, the Mn oxides produced by P. aeruginosa strain L3, either by the cell culture solution or by the fermentation supernatant, were bixbyite-type Mn2O3 with poor crystallinity. [ABSTRACT FROM AUTHOR]

Copper oxide nanoparticles were prepared by the solvothermal method, and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption-desorption measurements. The as-prepared CuO nanoparticles functionalized QCM resonators were fabricated and explored for HCN sensing under varied humidity conditions. When the humidity of air containing HCN is the same as that of environmental air, a characteristic positive frequency shift of CuO nanoparticles functionalized QCM resonator is always observed towards HCN because of a reversible surface redox reaction between CuO and HCN. The sensitivity of CuO nanoparticles functionalized QCM resonators increases with increase of relative humidity in the range of 9-51%. These results provide an important guidance for further developing HCN gas sensors towards practical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The method of promoting ilmenite flotation involves adding BHA to the mill was proposed. • The BHA synergistic mechanical activation can promote ilmenite flotation significantly. • The mechanism of BHA synergistic mechanical activation on ilmenite flotation was revealed. In this paper, the effect of the benzohydroxamic acid (BHA) synergistic mechanical activation on ilmenite flotation was systematically investigated. Flotation results revealed that the flotation recovery of ilmenite significantly increased with the addition of BHA before grinding as compared to the conventional process flow. Similar trend was observed in the flotation test of artificial mixed mineral. The addition of BHA to the mill has little effect on the size distribution of ilmenite, but it can increase the content of crystal surface (1 0 4) with the lowest surface energy of ilmenite. The results of Fourier-transform infrared spectroscopy (FT-IR) analysis showed that the addition of BHA before grinding resulted in improving the intensity and kinds of characteristic absorption peaks of BHA on the ilmenite surface. The addition of BHA to the mill effectively facilitated the interaction between ilmenite and BHA. Besides, the result of flotation kinetics demonstrated that the flotation kinetics of ilmenite could be well evaluated with the first-order kinetic model. And the flotation kinetic constant was improved by adding BHA before grinding, which was conducive and beneficial for enhancing the ilmenite flotation. [ABSTRACT FROM AUTHOR]

Highlights: [•] The visible-light-induced In2O3/rectorite was prepared by a facile sol–gel method. [•] The specific surface area of the In2O3/rectorite was larger than that of pure In2O3. [•] The photocatalyst shows excellent photocatalytic activity under visible-light irradiation. [ABSTRACT FROM AUTHOR]