| 1. |
- Fu, Yifeng, 1984, et al.
(författare)
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Templated Growth of Covalently Bonded Three-Dimensional Carbon Nanotube Networks Originated from Graphene
- 2012
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 24:12, s. 1576-1581
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Tidskriftsartikel (refereegranskat)abstract
- A template-assisted method that enables the growth of covalently bonded three-dimensional carbon nanotubes (CNTs) originating from graphene at a large scale is demonstrated. Atomic force microscopy-based mechanical tests show that the covalently bonded CNT structure can effectively distribute external loading throughout the network to improve the mechanical strength of the material.
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| 2. |
- Jiang, L., et al.
(författare)
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Experimental investigation on BOF slag oxidation in air
- 2019
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Ingår i: Ironmaking & steelmaking. - : Taylor and Francis Ltd.. - 0301-9233 .- 1743-2812. ; 46:8, s. 747-754
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Tidskriftsartikel (refereegranskat)abstract
- Basic oxygen furnace (BOF) slag contains a significant amount of iron-containing species, which is considered to be iron resources and therefore need to be recovered. In this work, the oxidation behaviour of BOF slag under air (at selected oxidation temperatures and holding time) was investigated to explore the potential of transforming non-magnetic wustite in the BOF slag into magnetic spinel, which may subsequently be recovered by magnetic separation. The experimental results show that the iron-containing spices in the BOF slag can be oxidised into magnetic spinel phases in the investigated temperature range of 1000–1150°C and thereafter be recovered by magnetic separation. The formation of these phases is closely related to the oxidation temperatures and holding time: a higher oxidation temperature and longer holding time lead to a larger amount of formed magnetic species; however, the amount of formed magnetic species decreases at elevated temperature (>1050°C) and with extended holding time (>40 min).
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| 3. |
- Xie, L., et al.
(författare)
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Performance analysis of safety barriers against cascading failures in a battery pack
- 2022
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Ingår i: Reliability Engineering & System Safety. - : Elsevier Ltd. - 0951-8320 .- 1879-0836. ; 228
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Tidskriftsartikel (refereegranskat)abstract
- Lithium-ion batteries have been widely employed as the principal power source in electric vehicles and other storage systems. However, some critical issues in a battery pack still exist, such as thermal failures on initial cells that impact the temperatures of the surrounding cells. Such cascading failures may significantly affect battery performance and safety. Thermal barriers, as one kind of safety barrier, are therefore installed to prevent failure propagations. This paper focuses on the situation when the temperature of battery cell increases, but the battery pack still can be used in a degradation mode since the barriers are against cascading failures. An approach is proposed to analyze how the deployment and performance of thermal barriers in a battery pack determine their capabilities against cascading failures. The approach includes thermal propagation models associated with the simulations, degradation models, reliability analysis, and barrier analysis. Its application is illustrated with a practical case study. The battery reliabilities are sensitive to many factors of the barriers, such as temperature differences, failed cells, and performance coefficient. The barriers between parallel cells are found to be more effective in mitigating failure propagation. Such findings can be beneficial for barrier optimization and reliability improvement of battery packs. © 2022 The Authors
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| 4. |
- Xu, Tianhua, et al.
(författare)
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Analysis of chromatic dispersion compensation and carrier phase recovery in long-haul optical transmission system influenced by equalization enhanced phase noise
- 2017
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Ingår i: Optik (Stuttgart). - : Elsevier GmbH. - 0030-4026 .- 1618-1336. ; 138, s. 494-508
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Tidskriftsartikel (refereegranskat)abstract
- The performance of long-haul coherent optical fiber transmission system is significantly affected by the equalization enhanced phase noise (EEPN), due to the interaction between the electronic dispersion compensation (EDC) and the laser phase noise. In this paper, we present a comprehensive study on different chromatic dispersion (CD) compensation and carrier phase recovery (CPR) approaches, in the n-level phase shift keying (n-PSK) and the n-level quadrature amplitude modulation (n-QAM) coherent optical transmission systems, considering the impacts of EEPN. Four CD compensation methods are considered: the time-domain equalization (TDE), the frequency-domain equalization (FDE), the least mean square (LMS) adaptive equalization are applied for EDC, and the dispersion compensating fiber (DCF) is employed for optical dispersion compensation (ODC). Meanwhile, three carrier phase recovery methods are also involved: a one-tap normalized least mean square (NLMS) algorithm, a block-wise average (BWA) algorithm, and a Viterbi-Viterbi (VV) algorithm. Numerical simulations have been carried out in a 28-Gbaud dual-polarization quadrature phase shift keying (DP-QPSK) coherent transmission system, and the results indicate that the origin of EEPN depends on the choice of chromatic dispersion compensation methods, and the effects of EEPN also behave moderately different in accordance to different carrier phase recovery scenarios.
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| 5. |
- Xu, T., et al.
(författare)
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Analytical estimation in differential optical transmission systems influenced by equalization enhanced phase noise
- 2016
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Ingår i: 2016 Progress In Electromagnetics Research Symposium, PIERS 2016 - Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509060931 ; , s. 4844-4848
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Konferensbidrag (refereegranskat)abstract
- An analytical model is presented for assessing the performance of the bit-error-rate (BER) in the differential m-level phase shift keying (m-PSK) transmission systems, where the influence of equalization enhanced phase noise (EEPN) has been considered. Theoretical analysis has been carried out in differential quadrature phase shift keying (DQPSK), differential 8-PSK (D8PSK), and differential 16-PSK (D16PSK) optical transmission systems. The influence of EEPN on the BER performance, in term of signal-to-noise ratio (SNR), are investigated for different fiber dispersion, LO laser linewidths, symbol rates, and modulation formats. Our analytical model achieves a good agreement with previously reported EEPN induced BER floors, and can give an accurate prediction for the DQPSK system, and a leading-order approximation for the D8PSK and the D16PSK systems.
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| 6. |
- Zhao, Shengzhong, et al.
(författare)
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A theoretical and experimental study on the buoyancy-driven smoke flow in a tunnel with vertical shafts
- 2019
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Ingår i: International journal of thermal sciences. - : Elsevier BV. - 1290-0729 .- 1778-4166. ; 141, s. 33-46
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a series of small-scale experiments was carried out in a model scale tunnel with dimensions of 20 m (Length) × 2 m (Width) × 1 m (Height) to investigate the characteristics of buoyancy-driven smoke flow in a tunnel with vertical shafts. Different shaft settings and four different longitudinal ventilation velocities were tested in the experiments. A theoretical model for the mass flow rate of buoyancy-driven smoke flow in the shaft was developed and validated. The gas temperature along the tunnel ceiling and smoke stratification were subsequently analyzed and discussed. The results showed that more shafts, greater shaft heights and greater shaft cross sectional areas can significantly increase the smoke extraction rate, and the total smoke mass flow rate in the shafts increases with the increasing ventilation velocity. The local pressure loss coefficient at the shaft inlet may not be a fixed value. An average value of 1.0 for this coefficient was recommended for engineering estimation and design of rectangular-shaped natural shafts. The presence of vertical shaft is beneficial to the smoke stratification and could increase the height of the smoke layer interface, especially for the downstream of the shaft.
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| 7. |
- Örnek, Cem, et al.
(författare)
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Volta Potential Evolution of Intermetallics in Aluminum Alloy Microstructure Under Thin Aqueous Adlayers : A combined DFT and Experimental Study
- 2018
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Ingår i: Topics in catalysis. - : Springer Science and Business Media LLC. - 1022-5528 .- 1572-9028. ; 61:9-11, s. 1169-1182
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Tidskriftsartikel (refereegranskat)abstract
- In this work, first-principle density functional theory (DFT) was used to calculate the work function and Volta potential differences between aluminum alloy matrix and two intermetallic phases (Mg2Si and Al2Cu) with varying surface terminations as a function of adhering monolayers (ML) of water. The calculated data were compared with experimental local Volta potential data obtained by the scanning Kelvin probe force microscopy (SKPFM) on a commercial aluminum alloy AA6063-T5 in atmospheric environments with varying relative humidity (RH). The calculations suggest that the surface termination has a major effect on the magnitude and polarity of the Volta potential of both intermetallic phases (IMP’s). The Volta potential difference between the IMP’s and the aluminum matrix decreases when the surface is gradually covered by water molecules, and may further change as a function of adhering ML’s of water. This can lead to nobility inversions of the IMP’s relative to the aluminum matrix. The measured Volta potential difference between both IMP’s and their neighboring matrix is dependent on RH. Natural oxidation in ambient indoor air for 2 months led to a nobility inversion of the IMP’s with respect to the aluminum matrix, with the intermetallics showing anodic nature already in dry condition. The anodic nature of Al2Cu remained with the introduction of RH, whereas Mg2Si became cathodic at high RH, presumably due to de-alloying of Mg and oxide dissolution. The DFT calculations predicted an anodic character of both IMP’s in reference to the oxidized aluminum matrix, being in good agreement with the SKPFM data. The DFT and SKPFM data were discussed in light of understanding localized corrosion of aluminum alloys under conditions akin to atmospheric exposure.
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