| 1. |
- Li, Jian-Li, et al.
(författare)
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Effect of FeO on the formation of spinel phases and chromium distribution in the CaO-SiO2-MgO-Al2O3-Cr2O3 system
- 2013
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Ingår i: International Journal of Minerals, Metallurgy and Materials. - : Springer Science and Business Media LLC. - 1674-4799 .- 1869-103X. ; 20:3, s. 253-258
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic slag samples of the CaO-SiO2-MgO-Al2O3-Cr2O3 system were obtained to clarify the effect of FeO on the formation of spinel phases and Cr distribution. X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS), as well as the thermodynamic software FactSage 6.2, were used for sample characterization. The results show that the addition of FeO can decrease the viscosity of molten slag and the precipitation temperatures of melilite and merwinite. The solidus temperature significantly decreases from 1400 to 1250 degrees C with the increase of FeO content from 0wt% to 6wt%. The addition of FeO could enhance the content of Cr in spinel phases and reduce the content of Cr in soluble minerals, such as merwinite, melilite, and dicalcium silicate. Hence, the addition of FeO is conducive to decreasing Cr leaching.
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| 2. |
- Wang, Yong-Lei, et al.
(författare)
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Microstructural and Dynamical Heterogeneities in Ionic Liquids
- 2020
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Ingår i: Chemical Reviews. - : American Chemical Society (ACS). - 0009-2665 .- 1520-6890. ; 120:13, s. 5798-5877
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Forskningsöversikt (refereegranskat)abstract
- Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation–anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
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| 3. |
- Wang, Zhong, et al.
(författare)
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Sabatier principle based design of high performance FeCoNiMnMoP high entropy electrocatalysis for alkaline water splitting
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 497
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Tidskriftsartikel (refereegranskat)abstract
- FeCoNi-based high entropy intermetallic compounds are promising substitutes for noble metal catalysts for hydrogen evolution reaction (HER) and oxygen evolution (OER), while their activity is restricted by the synergistic effect between the elements. In this paper, the theoretical model of FeCoNiMnMoP bifunctional catalyst has been reasonably designed given the volcanic curve of M−H bond energy as a valuable guide for candidate metal elements. Theoretical calculations show that the synergistic effect between multiple sites not only accelerates the electron transfer but also reduces the rate-determining step (RDS) barrier. At the same time, the introduction of Mo also enhances the total density of states and reduces the d-band center, thus optimizing the adsorption and dissociation of intermediates. The experimental results confirm that the theoretical model has excellent catalytic performance. In the alkaline solution, FeCoNiMnMoP‖FeCoNiMnMoP requires only an ultra-low cell voltage of 1.49 V for overall water splitting when the current density is 10 mA cm−2. In general, novel insights on the effects of intermetallic synergies on water decomposition are provided, which is helpful for the design of bifunctional catalysts based on volcanic diagrams.
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| 4. |
- Zhang, Hui-ning, et al.
(författare)
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Carbothermic Reduction of Zinc and Iron Oxides in Electric Arc Furnace Dust
- 2014
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X .- 2210-3988. ; 21:4, s. 427-432
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Tidskriftsartikel (refereegranskat)abstract
- The reduction of zinc and iron oxides from electric arc furnace dust (EAFD) by carbon was investigated at temperatures between 800 and 1300 °C. The analytic technique employed includes chemical analysis, X-ray fluorescence spectroscopy (XRF), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) equipped with X-ray energy dispersive spectrometry (EDS), and thermodynamic database FactSage 6. 2. It was found that the reduction of zinc and iron oxides depends largely on Boudouad reaction. At 900 °C, zinc exists in tested samples as ZnO, which is reduced in the temperature range of 1000 — 1100 °C. At 1100 °C, 99. 11% of the zinc is evaporated. The metallization ratio of Fe is 79. 19% at 1300 °C, as the content of Fe2+ is still 9. 40%. A higher temperature is thus required for a higher reduction degree of Fe oxides by solid or gaseous carbon
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| 5. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3– 19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8– 144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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| 6. |
- Chen, Xu-Guang, et al.
(författare)
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Analogical model test and theoretical analysis on zonal disintegration based on filed monitoring in deep tunnel
- 2013
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Ingår i: European Journal of Environmental and Civil Engineering. - : Informa UK Limited. - 1964-8189 .- 2116-7214. ; 17:Suppl. 1, s. 33-52
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Tidskriftsartikel (refereegranskat)abstract
- Field monitoring carried out in a deep tunnel of the Dingji coal mine in China confirmed the zonal disintegration phenomenon by using the borehole TV. Based on field monitoring, an analogical model test was conducted to research the fracture shape and forming conditions of the rock mass in the Dingji mine. To perform the model test, an analogical material and optical sensor were developed independently. Through the test, the occurrence of zonal disintegration was confirmed and the forming process was monitored. The fracture pattern of zonal disintegration was determined, and the radii of the fractured zones were found to fulfil the relationship of geometric progression. The displacement laws of surrounding rocks during zonal disintegration were obtained and found to be non-monotonic. The test results are in agreement with the field-monitoring results. Through a theory analysis based on fracture mechanics, the mechanism of zonal disintegration was revealed. The fracture zones occur as circles concentric to the cavern periphery, which is the “false face”. Each fracture zone ruptures at the elastic–plastic boundary of surrounding rocks and then coalesces into a circle. The geometric progression ratio was determined; it is related to the mechanical parameters and ground stress of the surrounding rocks and calculated as follows: And the mechanism of the non-monotonic displacement law is revealed; the continuous formation of the “false face” causes the geostress redistribution and crack opening.
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| 7. |
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| 8. |
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| 9. |
- Gong, Liang, et al.
(författare)
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Training feed-forward neural networks using the gradient descent method with the optimal stepsize
- 2012
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Ingår i: Journal of Computational Information Systems. - 1553-9105. ; 8:4, s. 1359-1371
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Tidskriftsartikel (refereegranskat)abstract
- The most widely used algorithm for training multiplayer feedforward networks, Error BackPropagation (EBP), is an iterative gradient descend algorithm by nature. Variable stepsize is the key to fast convergence of BP networks. A new optimal stepsize algorithm is proposed for accelerating the training process. It modifies the objective function to reduce the computational complexity of the Jacobin and consequently that of Hessian matrices, and hereby directly computes the optimal iterative stepsize. The improved backpropagation algorithm helps alleviating the problem of slow convergence and oscillations. The analysis indicates that the backpropagation with optimal stepsize (BPOS) is more efficient when treating large-scale samples. The numerical experiment results on pattern recognition and function approximation problems show that the proposed algorithm possesses the features of fast convergence and less intensive computational complexity.
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| 10. |
- Han, Jingrui, et al.
(författare)
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Lattice Oxygen Activation through Deep Oxidation of Co4N by Jahn–Teller–Active Dopants for Improved Electrocatalytic Oxygen Evolution
- 2024
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Ingår i: Angewandte Chemie International Edition. - : John Wiley & Sons. - 1433-7851 .- 1521-3773. ; 63:33
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Tidskriftsartikel (refereegranskat)abstract
- Triggering the lattice oxygen oxidation mechanism is crucial for improving oxygen evolution reaction (OER) performance, because it could bypass the scaling relation limitation associated with the conventional adsorbate evolution mechanism through the direct formation of oxygen–oxygen bond. High-valence transition metal sites are favorable for activating the lattice oxygen, but the deep oxidation of pre-catalysts suffers from a high thermodynamic barrier. Here, taking advantage of the Jahn–Teller (J–T) distortion induced structural instability, we incorporate high-spin Mn3+ ( ) dopant into Co4N. Mn dopants enable a surface structural transformation from Co4N to CoOOH, and finally to CoO2, as observed by various in situ spectroscopic investigations. Furthermore, the reconstructed surface on Mn-doped Co4N triggers the lattice oxygen activation, as evidenced experimentally by pH-dependent OER, tetramethylammonium cation adsorption and online electrochemical mass spectrometry measurements of 18O-labelled catalysts. In general, this work not only offers the introducing J–T effect approach to regulate the structural transition, but also provides an understanding about the influence of the catalyst's electronic configuration on determining the reaction route, which may inspire the design of more efficient catalysts with activated lattice oxygen.
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