| 1081. |
- Li, P., et al.
(författare)
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Novel concept of steam modification towards energy and iron recovery from steel slag : Oxidation mechanism and process evaluation
- 2020
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Ingår i: Journal of Cleaner Production. - : Elsevier Ltd. - 0959-6526 .- 1879-1786. ; 254
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Tidskriftsartikel (refereegranskat)abstract
- The motivation of this work is driven by the feasible hydrogen production, through the reaction between iron-bearing phases, i.e. RO phase, metallic Fe in steel slag and steam. The RO phase can be regarded as (Mn,Mg,Ca)xFe1-xO wüstite that divalent iron is partially substituted by foreign cations of magnesium, manganese and calcium. The reaction behavior in terms of hydrogen generation variation in the temperature range of 500–1000 °C has been studied. It was found that the hydrogen production rate was strongly temperature dependent. Under isothermal conditions, the steel slag-steam reaction proceeded rapidly during the first 2000s. Beyond this, the rate of the reaction decreased significantly due to the formation of (Mg,Mn,Ca)yFe3-yO4 ferrite layer. The theoretical hydrogen generation capacity for steel slag was found to be proportional to the substitution level of foreign cations, i.e. Mg, Mn, Ca in wüstite. The underlying phase transitions, as well as the structural changes were discussed in detail by combing the XRD, SEM-EDS, XPS and VSM analysis. The kinetics analysis showed that the slag-steam reaction agreed well with the three-dimensional diffusion (D3) model and the corresponding activation energy for diffusion was estimated as 105.76 kJ/mol. Moreover, it was noticed that the magnetic properties of steel slag after steam oxidation was greatly enhanced, and the maximum specific magnetic susceptibility was 1.8E-4 m3/kg at 800 °C. This demonstrated steam oxidation could significantly improve the magnetism of steel slag and provide the possibility of iron recovering through magnetic separation. Based on the findings, the novel concept of the steam modification process towards highly efficient utilization of steel slag along its cooling path was proposed. It allowed us to envision the potentials that implementing management of energy production, iron recovery, and volumetric stabilization.
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| 1082. |
- Li, Peng, et al.
(författare)
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Understanding reactions between water and steelmaking slags : Iron distribution, hydrogen generation, and phase transformations
- 2022
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 47:48, s. 20741-20754
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Tidskriftsartikel (refereegranskat)abstract
- Environmentally friendly energy harvesting can be achieved by the H2O thermochemical treatment of steelmaking slags. Hot slag from steel manufacturing is used as a sacrificial material to produce H2 in a stream of steam. In parallel, this process enhances the magnetic properties of the slag, benefitting the Fe recovery. In this work, the occurrence states of different iron species in slags, as well as their reactivity and phase transformations in H2O, were investigated. The results showed that Fe2+ was mainly distributed in olivine (Ca, Fe, Mg, Mn)2SiO4 when the basicity was low. As the basicity increased, a gradual enrichment of Fe2+ in RO phase (divalent oxides solid solution, R = Fe, Mg, Mn etc.) was observed. In addition to steelmaking slags, the H2O splitting reactions of synthetic model iron compounds, RO phase (Mg1-xFexO, x = 0.36, 0.63, 0.77) and kirschsteinite (CaFeSiO4) were also tested. RO phase exhibited fast kinetics, with its activity proportional to the FeO content. Oxidation of the magnesia-rich RO phase resulted in the phase segregation of iron-depleted magnesiowustite (Mg,Fe-depleted)O and iron-rich spinel (Mg, Fe-rich)3O4. The H2O splitting of CaFeSiO4 suffered from extremely low kinetics below 900 degrees C, which could be enhanced by raising the temperature. The H2 production capacity of steelmaking slags was strongly affected by the basicity, which improved when more Fe2+ existed as RO phase rather than CaFeSiO4. After oxidation in steam at 850 degrees C, the slag sample with a basicity of 1.83 produced 29.3 cm3.g(material)-1 hydrogen at 850 degrees C for 60 min, with a conversion ratio of 80.1%.
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| 1083. |
- Li, Peiran, et al.
(författare)
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Understanding rooftop PV panel semantic segmentation of satellite and aerial images for better using machine learning
- 2021
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Ingår i: Advances in Applied Energy. - : Elsevier BV. - 2666-7924. ; 4, s. 100057-100057
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Tidskriftsartikel (refereegranskat)abstract
- The photovoltaic (PV) industry boom and increased PV applications call for better planning based on accurate and updated data on the installed capacity. Compared with the manual statistical approach, which is often time-consuming and labor-intensive, using satellite/aerial images to estimate the existing PV installed capacity offers a new method with cost-effective and data-consistent features. Previous studies investigated the feasibility of segmenting PV panels from images involving machine learning technologies. However, due to the particular characteristics of PV panel semantic-segmentation, the machine learning tools need to be designed and applied with careful considerations of the issue formulation, data quality, and model explainability. This paper investigated the characteristics of PV panel semantic-segmentation from the perspective of computer vision. The results reveal that the PV panel image data has several specific characteristics: highly class-imbalance and non-concentrated distribution; homogeneous texture and heterogenous color features; and the notable resolution threshold for effective semantic-segmentation. Moreover, this paper provided recommendations for data obtaining and model design, aiming at each observed character from the viewpoints of recent solutions in computer vision, which can be helpful for future improvement of the PV panel semantic-segmentation.
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| 1084. |
- Li, Qi, et al.
(författare)
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Construction of cellulose-based Pickering stabilizer as a novel interfacial antioxidant : A bioinspired oxygen protection strategy
- 2020
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 229
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen protection/isolation is imperative to prevent the lipid oxidation since oxygen molecule is an ultimate quencher in photon conversion process. Inspired by the structural buildup of seeds from oil crops, a sustainable solid particle stabilizer with novel antioxidant activity was prepared by using cellulose and polyphenol. In this work, bacterial cellulose (BC) nanofibrils modified by tea polyphenols (TPs) was prepared and used as Pickering emulsifier for the O/W emulsion. BC nanofibirls exhibited excellent adsorption capacity up to 55 mu g/mg, and the adsorption kinetics between BC and TPs were further investigated. After modification, the interfacial diffusion rate constant of BC was significantly increased to from 0.43 to 1.21 mN m(-1) s(-0.5). Moreover, the obtained O/W interfacial modulus of the dilatational elasticity was increased from 58 to 130 mN/m. Furthermore, the emulsions exhibited excellent free-radical scavenging activity at oil-water interface, suggesting a potential application in usage to extend the lifespan of the food containing polyunsaturated fats.
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| 1085. |
- Li, Qiang, et al.
(författare)
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Efficient directional coupler based on plasmonic waveguide for photonic integrated circuits
- 2010
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Ingår i: International Conference on Optical Communications and Networks 2010. - : IET. - 9781849193146 ; , s. 366-368
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Konferensbidrag (refereegranskat)abstract
- Two asymmetric directional couplers, including the dielectric-hybrid plasmonic coupler and the dielectric-metalinsulator-metal plasmonic coupler, are investigated. The proposed hybrid coupler features short coupling length, high coupling efficiency and can be integrated into the siliconbased platform. The applications of these hybrid couplers include the signal routing between plasmonic waveguides and dielectric waveguides in photonic integrated circuits and efficient excitation of plasmonic modes with conventional dielectric modes. Besides, a symmetric directional coupler based on silver nanowires is also demonstrated.
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| 1086. |
- Li, Qiang, et al.
(författare)
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Experimental Demonstration of Plasmon Propagation, Coupling, and Splitting in Silver Nanowire at 1550-nm Wavelength
- 2011
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 17:4, s. 1107-1111
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Tidskriftsartikel (refereegranskat)abstract
- We experimentally demonstrate silver-nanowire-based plasmonic devices including the nanowaveguide, the nanocoupler, and the nanosplitter at optical communication wavelength of 1550 nm. The plasmon propagation loss in a 300-nm diameter silver nanowire is measured to be 0.3 dB/mu m and the effective propagation length is 14.5 mu m. This loss is comparatively lower than that at 980 nm. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nanocouplers, and nanosplitters, are realized. For the nanocoupler, the experimental results show that the plasmonic modes can be efficiently coupled between two closely positioned nanowires. While for the nanosplitter, the plasmonic mode is split with a power ratio of 2.6:1. These demonstrations experimentally prove the feasibility of extending the operating wavelength of silver-nanowire-based plasmonic devices to current optical communication wavelength with a lower loss, which are thus important steps for potentially utilizing low-loss nanowire-based plasmonic components for photonic integrated circuits.
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| 1087. |
- Li, Qiang, et al.
(författare)
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Experimental demonstration of plasmon propagation, coupling, and splitting in silver nanowire at 1550-nm wavelength
- 2011
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - : IEEE. - 1077-260X .- 1558-4542. ; 17:4, s. 1107-1111
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Tidskriftsartikel (refereegranskat)abstract
- We experimentally demonstrate silver-nanowire-based plasmonic devices including the nanowaveguide, the nanocoupler, and the nanosplitter at optical communication wavelength of 1550 nm. The plasmon propagation loss in a 300-nm diameter silver nanowire is measured to be 0.3 dB/μm and the effective propagation length is 14.5 μm. This loss is comparatively lower than that at 980 nm. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nanocouplers, and nanosplitters, are realized. For the nanocoupler, the experimental results show that the plasmonic modes can be efficiently coupled between two closely positioned nanowires. While for the nanosplitter, the plasmonic mode is split with a power ratio of 2.6:1. These demonstrations experimentally prove the feasibility of extending the operating wavelength of silver-nanowire-based plasmonic devices to current optical communication wavelength with a lower loss, which are thus important steps for potentially utilizing low-loss nanowire-based plasmonic components for photonic integrated circuits.
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| 1088. |
- Li, Qiang, et al.
(författare)
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Silver nanowire based plasmon propagation, coupling and splitting at 1.55 mu m wavelength
- 2011
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Ingår i: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 7986
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Tidskriftsartikel (refereegranskat)abstract
- We experimentally demonstrate silver nanowire based plasmonic devices at optical communication wavelength 1.55 mu m. The plasmon propagation loss in a 300 nm diameter silver nanowire is measured to be 0.3 dB/mu m. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nano-couplers and nano-splitters, are realized.
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| 1089. |
- Li, Qiang, et al.
(författare)
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Silver nanowire based plasmon propagation, coupling and splitting at 1.55 μm wavelength
- 2010
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Ingår i: 2010 Asia Communications and Photonics Conference and Exhibition, ACP 2010. - 9781424471119 ; , s. 497-498
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Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate silver nanowire based plasmonic devices at optical communication wavelength 1.55 μm. The plasmon propagation loss in a 300 nm diameter silver nanowire is measured to be 0.3 dB/μm. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nano-couplers and nano-splitters, are realized.
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| 1090. |
- Li, Qiang, et al.
(författare)
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Silver nanowire based plasmon propagation, coupling and splitting at 1.55 μm wavelength
- 2010
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Ingår i: Optics InfoBase Conference Papers. - Washington, D.C. : Optical Society of America (OSA). - 9780819485540
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Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate silver nanowire based plasmonic devices at optical communication wavelength 1.55 μm. The plasmon propagation loss in a 300 nm diameter silver nanowire is measured to be 0.3 dB/μm. Two types of plasmonic functional devices based on the coupling between two silver nanowires, nano-couplers and nano-splitters, are realized.
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