| 1. |
- Dang, Jie, et al.
(författare)
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Electromagnetic Design Considerations for a 50,000 rpm 1kW Switched Reluctance Machine using a Flux Bridge
- 2013
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Ingår i: IEEE International Electric Machines and Drives Conference (IEMDC 2013). - 9781467349758 ; , s. 325-331
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Konferensbidrag (refereegranskat)abstract
- The Switched Reluctance Machine (SRM) is a robust machine and is a candidate for ultra high speed applications. Until now the area of ultra high speed machines has been dominated by permanent magnet machines (PM). The PM machine has a higher torque density and some other advantages compared to SRMs. However, the soaring prices of the rare earth materials are driving the efforts to find an alternative to PM machines without significantly impacting the performance. At the same time significant progress has been made in the design and control of the SRM. This paper reviews the progress of the SRM as a high speed machine and proposes a novel rotor structure design to resolve the challenge of high windage losses at ultra high speed. It then elaborates on the path of modifying the design to achieve optimal performance. The simulation result of the final design is verified on FEA software. Finally, a prototype machine with similar design is built and tested to verify the simulation model. The experimental waveform indicates good agreement with the simulation result. Therefore, the performance of the prototype machine is analyzed and presented at the end of this paper.
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| 2. |
- Liu, Dong, et al.
(författare)
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Nitrogen-Doped MoS2/Ti3C2TX Heterostructures as Ultra-Efficient Alkaline HER Electrocatalysts
- 2021
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 60:13, s. 9932-9940
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Tidskriftsartikel (refereegranskat)abstract
- Molybdenum disulfide (MoS2) is intrinsically inert for the hydrogen evolution reaction (HER) in alkaline media due to its electronic structures. Herein, we tune the electronic structures of MoS2 by a combined strategy of post-N doping coupled with the synergistic effect of Ti3C2TX. The as-prepared N-doped MoS2/Ti3C2TX heterostructures show remarkable alkaline HER activity with an over-potential of 225 mV at 140 mA cm(-2), which ranks the N-doped MoS2/Ti3C2TX heterostructures among the best MoS2/MXene-based electrocatalysts reported for alkaline HER. The first-principles calculations indicate that the N doping can enhance the activation of nearby S sites of MoS2/Ti3C2TX and thus promote the HER process. This strategy provides a promising way to develop high-efficiency MoS2/MXene heterostructure catalysts for alkaline HER.
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| 3. |
- Lv, Zepeng, et al.
(författare)
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Designed synthesis of WC-based nanocomposites as low-cost, efficient and stable electrocatalysts for the hydrogen evolution reaction
- 2020
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Ingår i: CrystEngComm. - : ROYAL SOC CHEMISTRY. - 1466-8033. ; 22:27, s. 4580-4590
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Tidskriftsartikel (refereegranskat)abstract
- It still remains a great challenge to develop alternative electrocatalysts with low cost, high efficiency and good stability for the hydrogen evolution reaction (HER). In this study, effectively conductive rGO (reduced graphene oxide) was used as the support both to promote charge transfer and to refine the particle size of WC, to realize efficient and stable HER performance. The facilein situmethod can make highly dispersed WC nanoparticles firmly anchor onto the rGO substrate. Benefiting from its unique morphology and strong synergistic effect, the designed WC@rGO achieves a giant improvement in HER activity in both acidic and alkaline solutions compared with pristine WC. The overpotentials of WC@rGO are 2.82 and 2.30 times smaller than those of pristine WC to achieve 10 mA cm(-2) in acid and alkaline solutions. More specifically, the Pt-modified WC electrocatalyst with negligible accumulation of Pt (4 wt%) even exhibits superior electrocatalytic performance (eta(10) and Tafel slope of 54 mV and 21 mV dec(-1) in acid solution and 61 mV and 28 mV dec(-1) in alkaline solution) to commercial 10 wt% Pt@C. The method reported in this study enables eco-friendly preparation of cheap, stable and effective HER electrodes.
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| 4. |
- Trung, Hieu Tran, et al.
(författare)
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Anti-inflammatory and Antiphytopathogenic Fungal Activity of 2,3-seco-Tirucallane Triterpenoids Meliadubins A and B from Melia dubia Cav. Barks with ChemGPS-NP and In Silico Prediction
- 2023
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 8:40, s. 37116-37127
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Tidskriftsartikel (refereegranskat)abstract
- Two new rearranged 2,3-seco-tirucallane triterpenoids, meliadubins A (1) and B (2), along with four known compounds, 3-6, were isolated from the barks of Melia dubia Cav. Compound 2 exhibited a significant inflammatory inhibition effect toward superoxide anion generation in human neutrophils (EC50 at 5.54 +/- 0.36 mu M). It bound to active sites of a human inducible nitric oxide synthase (3E7G) through interactions with the residues of GLU377 and PRO350, which may benefit in reducing the neutrophilic inflammation effect. The ChemGPS-NP interpretation combined with bioactivity assay and in silico prediction results suggested 2 to be an agent for targeting iNOS with different mechanisms as compared to a selected set of current approved drugs. Moreover, compounds 1 and 2 showed remarkable inhibition against the rice pathogenic fungus Magnaporthe oryzae in a dose-dependent manner with IC50 values of 137.20 +/- 9.55 and 182.50 +/- 18.27 mu M, respectively. Both 1 and 2 displayed interactions with the residue of TYR223, a key active site of trihydroxynaphthalene reductase (1YBV). The interpretation of 1 and 2 in the ChemGPS-NP physical-chemical property space indicated that both compounds are quite different compared to all members of a selected set of reference compounds. In light of demonstrated biological activity and in silico prediction experiments, both compounds possibly exhibited activity against phytopathogenic fungi via a novel mode of action.
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| 5. |
- Zhao, Jun, et al.
(författare)
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Using Green, Economical, Efficient Two-Dimensional (2D) Talc Nanosheets as Lubricant Additives under Harsh Conditions
- 2022
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) nanomaterials have attracted much attention for lubrication enhancement of grease. It is difficult to disperse nanosheets in viscous grease and the lubrication performances of grease under harsh conditions urgently need to be improved. In this study, the 2D talc nanosheets are modified by a silane coupling agent with the assistance of high-energy ball milling, which can stably disperse in grease. The thickness and size of the talc nanosheet are about 20 nm and 2 µm. The silane coupling agent is successfully grafted on the surface of talc. Using the modified-talc nanosheet, the coefficient of friction and wear depth can be reduced by 40% and 66% under high temperature (150 °C) and high load (3.5 GPa), respectively. The enhancement of the lubrication and anti-wear performance is attributed to the boundary adsorbed tribofilm of talc achieving a repairing effect of the friction interfaces, the repairing effect of talc on the friction interfaces. This work provides green, economical guidance for developing natural lubricant additives and has great potential in sustainable lubrication.
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