| 311. |
- Yuan, Jinliang, et al.
(författare)
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Modeling and analysis of A bio-fuelled ceramic fuel cell stack
- 2004
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Ingår i: Fuel Cell Science, Engineering and Technology - 2004. - : ASMEDC. - 0791841650 - 9780791841655 ; , s. 453-459
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Konferensbidrag (refereegranskat)abstract
- Recent development in the advanced ceramic fuel cell (CFC), working at intermediate temperature 600-700°C, brings up feasibility and new opportunity to employ renewable fuels with this innovative technology. It may offer a better solution concerning environment, natural resources and development of our civil society. Moreover, direct oxidation of hydrocarbon fuels at intermediate temperature possesses great advantage in avoiding complex and expensive external reforming process. This paper presents modeling and analysis of an inter-mediate temperature CFC stack. The model is a general one to evaluate the stack performance for the purpose of optimal design and/or configuration based on the specified electrical power or fuel supply rate, except that the Tafel coefficients are adjusted and/or obtained to match experimental data. The energy and gas flow data obtained from the investigation can be further used to identify the heat exchanger network configurations and optimal operating conditions using process integration techniques. The model can be applied as a stand alone one, or implemented into an overall energy system modeling for the purpose of system study.
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| 312. |
- Yuan, K., et al.
(författare)
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A new technology for spraying advanced low-temperature (300∼600 °C) Solid oxide fuel cells
- 2017
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Ingår i: Proceedings of the International Thermal Spray Conference. - : ASM International. - 9781510858220 ; , s. 132-137
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Konferensbidrag (refereegranskat)abstract
- Solid oxide fuel cell (SOFC) has been developed for a hundred year and met a great challenge on material design and marketing. In recent years, new SOFC materials are dug up to achieve high energy-output performance at lower working temperature (300∼600 °C), namely low-temperature SOFC (LTSOFC). In this study, Ni-Co-Al-Li oxide (NCAL) was used for making dense, thin and uniform coatings on grooved bipolar electrode substrate for LTSOFC. Low-pressure plasma spray (LPPS) technology was applied to manufacture the NCAL coatings. The performance of a fuel cell package using the coated bipolars was tested between 350 and 600 °C, showing 6∼8 W power output with 4 single fuel cells (active area of 25 cm2). The LPPS technology is believed to be one of the ultimate ways for manufacturing the thin film/coatings for SOFC applications in future.
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| 313. |
- Yuan, Shuai, et al.
(författare)
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Tunable metal hydroxide-organic frameworks for catalysing oxygen evolution
- 2022
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-1122 .- 1476-4660. ; 21:6, s. 673-680
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Tidskriftsartikel (refereegranskat)abstract
- The oxygen evolution reaction is central to making chemicals and energy carriers using electrons. Combining the great tunability of enzymatic systems with known oxide-based catalysts can create breakthrough opportunities to achieve both high activity and stability. Here we report a series of metal hydroxide–organic frameworks (MHOFs) synthesized by transforming layered hydroxides into two-dimensional sheets crosslinked using aromatic carboxylate linkers. MHOFs act as a tunable catalytic platform for the oxygen evolution reaction, where the π–π interactions between adjacent stacked linkers dictate stability, while the nature of transition metals in the hydroxides modulates catalytic activity. Substituting Ni-based MHOFs with acidic cations or electron-withdrawing linkers enhances oxygen evolution reaction activity by over three orders of magnitude per metal site, with Fe substitution achieving a mass activity of 80 A g−1catalyst at 0.3 V overpotential for 20 h. Density functional theory calculations correlate the enhanced oxygen evolution reaction activity with the MHOF-based modulation of Ni redox and the optimized binding of oxygenated intermediates.
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| 314. |
- Zeng, Xiangze, et al.
(författare)
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Elucidating dominant pathways of the nano-particle self-assembly process
- 2016
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 18:34, s. 23494-23499
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Tidskriftsartikel (refereegranskat)abstract
- Self-assembly processes play a key role in the fabrication of functional nano-structures with widespread application in drug delivery and micro-reactors. In addition to the thermodynamics, the kinetics of the self-assembled nano-structures also play an important role in determining the formed structures. However, as the self-assembly process is often highly heterogeneous, systematic elucidation of the dominant kinetic pathways of self-assembly is challenging. Here, based on mass flow, we developed a new method for the construction of kinetic network models and applied it to identify the dominant kinetic pathways for the self-assembly of star-like block copolymers. We found that the dominant pathways are controlled by two competing kinetic parameters: the encounter time Te, characterizing the frequency of collision and the transition time Tt for the aggregate morphology change from rod to sphere. Interestingly, two distinct self-assembly mechanisms, diffusion of an individual copolymer into the aggregate core and membrane closure, both appear at different stages (with different values of Tt) of a single self-assembly process. In particular, the diffusion mechanism dominates the middle-sized semi-vesicle formation stage (with large Tt), while the membrane closure mechanism dominates the large-sized vesicle formation stage (with small Tt). Through the rational design of the hydrophibicity of the copolymer, we successfully tuned the transition time Tt and altered the dominant self-assembly pathways.
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| 315. |
- Zhang, Daquan, et al.
(författare)
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Large-scale planar and spherical light-emitting diodes based on arrays of perovskite quantum wires
- 2022
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 16:4, s. 284-290
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Tidskriftsartikel (refereegranskat)abstract
- Halide perovskites are enticing candidates for highly efficient planar light-emitting diodes (LEDs) with commercial potential in displays and lighting. However, it remains a challenge for conventional solution fabrication processes to fabricate large-scale or non-planar LEDs due to the non-uniformity of perovskite films in conjunction with material stability issues. Here large-area highly uniform arrays of crystalline perovskite quantum wires are grown with emission spectra covering the whole visible range. Photoluminescence quantum yield of up to 92% and 5,644 hours as the time for photoluminescence to degrade down to its 50% of the initial value under ambient conditions are achieved for MAPbBr3 quantum wires. LEDs based on these quantum wires on rigid and flexible planar substrates are fabricated up to a four-inch wafer size and also unique three-dimensional spherical LEDs with outstanding uniformity are reported. The results suggest that the approach developed here can be generalized to other unconventional three-dimensional LEDs in the future.
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| 316. |
- Zhang, Fan, et al.
(författare)
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Proliferative and Survival Effects of PUMA Promote Angiogenesis
- 2012
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Ingår i: Cell Reports. - : Elsevier (Cell Press). - 2211-1247. ; 2:5, s. 1272-1285
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Tidskriftsartikel (refereegranskat)abstract
- The p53 upregulated modulator of apoptosis (PUMA) is known as an essential apoptosis inducer. Here, we report the seemingly paradoxical finding that PUMA is a proangiogenic factor critically required for the proliferation and survival of vascular and microglia cells. Strikingly, Puma deficiency by genetic deletion or small hairpin RNA knockdown inhibited developmental and pathological angiogenesis and reduced microglia numbers in vivo, whereas Puma gene delivery increased angiogenesis and cell survival. Mechanistically, we revealed that PUMA plays a critical role in regulating autophagy by modulating Erk activation and intracellular calcium level. Our findings revealed an unexpected function of PUMA in promoting angiogenesis and warrant more careful investigations into the therapeutic potential of PUMA in treating cancer and degenerative diseases.
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| 317. |
- Zhang, Wei, et al.
(författare)
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Mixed ionic-electronic conductor membrane based fuel cells by incorporating semiconductor Ni0.8Co0.15Al0.05LiO2-delta into the Ce0.8Sm0.2O2-delta-Na2CO3 electrolyte
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 41:34, s. 15346-15353
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, a novel composite was fabricated by incorporating the semiconductor Ni0.8Co0.15Al0.05LiO2-delta (NCAL) into the ionic electrolyte Ce0.8Sm0.2O2-delta-Na2CO3 (NSDC), and further developed as a mixed-conducting membrane for single layer fuel cell (SLFC) applications. Experimentally, the crystal structure, morphology, chemical composition and thermo-stability of the composite were characterized by XRD, SEM and TGA. The best cell performance was investigated when the NSDC-NCAL membrane was optimized at a weight ratio of 6:4. On this basis, a number of interesting findings were obtained: i) the mixed conducting membrane did not cause any short circuit; on the contrary, the cell reached a decent open circuit voltage (OCV) of similar to 1.0 V. a high power density of 1072 mW cm(-2) was achieved at 550 degrees C for the NSDC-NCAL membrane based cell, which was much better than that using a pure NSDC electrolyte membrane. Electrochemical impedance spectroscopy (EIS) showed that the NSDC-NCAL composite exhibited significantly improved grain boundary conduction and reduced electrode polarizations, contributing to the resultant performance. To consolidate the usefulness of the device, we also conducted the durability test. The above findings indicate the strategy of introducing mixed NSDC-NCAL membrane is feasible for high-performance SLFCs operating at low temperatures.
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| 318. |
- Zhang, Wei, et al.
(författare)
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The fuel cells studies from ionic electrolyte Ce0.8Sm0.05Ca0.15O2-delta to the mixture layers with semiconductor Ni0.8Co0.15Al0.05LiO2-delta
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 41:41, s. 18761-18768
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Tidskriftsartikel (refereegranskat)abstract
- The mixture of ionic electrolyte Ce0.8Sm0.05Ca0.15O2-delta (SCDC) and semiconductor Ni0.8Co0.15Al0.05LiO2-delta (NCAL) layers was used for low temperature solid oxide fuel cell (LT-SOFC) applications. Using the as-prepared SCDC-NCAL semiconductor-ionic layer to replace the ionic SCDC electrolyte, following results have been obtained: the SCDC electrolyte fuel cell reached a lower voltage, 1.05 V, and lower power output, 415 mW cm(-2), compared to that using the semiconductor-ionic layer, 1.06 V and 617 mW cm(-2) at 550 degrees C. The electrochemical impedance spectroscopy (EIS) was applied to investigate the electrochemical processes of the device; X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM) for the microstructure and morphology of the as-prepared materials. The results have illuminated that the introduction of semiconductor into ionic electrolyte could make extended triple phase boundary (TPB) area, which can provide more active sites to accelerate the fuel cell reactions and enhance the cell performance. Furthermore, we also discovered that the ionic SCDC and electronic NCAL should be in an appropriate composition to achieve a balanced ionic and electronic conductivity, which is the key issue for high performance semiconductor-ionic fuel cells.
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| 319. |
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| 320. |
- Zhang, Yifei, et al.
(författare)
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Superionic Conductivity in Ceria-Based Heterostructure Composites for Low-Temperature Solid Oxide Fuel Cells
- 2020
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Ingår i: Nano-Micro Letters. - : Springer Science and Business Media LLC. - 2150-5551 .- 2311-6706. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Ceria-based heterostructure composite (CHC) has become a new stream to develop advanced low-temperature (300–600 °C) solid oxide fuel cells (LTSOFCs) with excellent power outputs at 1000 mW cm−2 level. The state-of-the-art ceria–carbonate or ceria–semiconductor heterostructure composites have made the CHC systems significantly contribute to both fundamental and applied science researches of LTSOFCs; however, a deep scientific understanding to achieve excellent fuel cell performance and high superionic conduction is still missing, which may hinder its wide application and commercialization. This review aims to establish a new fundamental strategy for superionic conduction of the CHC materials and relevant LTSOFCs. This involves energy band and built-in-field assisting superionic conduction, highlighting coupling effect among the ionic transfer, band structure and alignment impact. Furthermore, theories of ceria–carbonate, e.g., space charge and multi-ion conduction, as well as new scientific understanding are discussed and presented for functional CHC materials.
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