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1.
《International Journal of Hydrogen Energy》2022,47(2):1306-1318
The effective and efficient utilization of low-calorific value (LCV) gases has gained increasing attention in scientific research and industrial fields. In this study, the combustion characteristics of three LCV gases in practical devices are analyzed by using a nonadiabatic perfectly stirred reactor model. The complete steady-state solution in the temperature-residence time parameter space is obtained with arc-length continuation. The stable operation region is quantified by the eigenvalue analysis. The transition of solution curves is quantified with heat loss coefficient. Five key system parameters are systematically investigated on their effects on stability limits. With the combustion performance being quantified by a combustion state index, a combustion state regulation method is proposed to find the optimal regulation path of system parameters. Active subspace method is further applied to shorten the regulation step by identifying the active direction. The proposed method and findings are useful for optimal regulation of burning LCV gases in industrial burners. 相似文献
2.
《Ceramics International》2022,48(18):25984-25995
Design of architectured composites with layered-ordered structure can solve the strength-toughness mismatch problem of structural materials. In the present study, heterostructure Ti6Al4V/TiAl laminated composite sheets with different thicknesses of interface layer and TiAl composite layer were successfully produced by hot-pressing technology. The effects of interface regulation and laminated structure on their mechanical properties, crack propagation, and fracture behavior were studied. The results indicated that compressive strength of the sheets increased with the decrease in interface thickness. Compressive strength of TiAl composite sheet with thicker composite layer reached 1481.55 MPa at the arrester orientation with sintering holding time of 40 min, which was 25.96% higher than that of the sheet obtained at 120 min. Analysis indicated that the interface area transferred stress through slip bands and through-interface cracks. Compressive strength at the divider orientation reached 1443.06 MPa, which was 45.78% higher than that of the sheet obtained at 120 min. In this case, the interface area transferred stress through slip bands and along-interface cracks. For TiAl composite sheets with thinner composite layer, compressive strength was further improved to 1631.01 MPa and 1594.66 MPa at the arrester and divider orientations with sintering holding time of 40 min, respectively. The ductile metal layer exerted a significant toughening effect. Both interface regulation and laminated structure transformation could enhance the hetero-deformation induced (HDI) strengthening and improve the comprehensive mechanical properties of the composite sheets. 相似文献
3.
《Ceramics International》2022,48(13):18793-18802
The luminescence center energy transfer, crystal field strength, and covalency are limited by the crystal structure of the host and subsequently affect the luminescence efficiency, color, and intensity. Here, we report an excellent red phosphor BaLaLiWO6:0.40Eu3+ and the dependence between symmetry and luminous performance. A model for changing symmetry is drawn by analyzing the Coulomb potential and structure for the application of a double-perovskite phosphor BLLWO: Dy3+, Eu3+ in white light LEDs. The addition of Dy3+/Eu3+ makes the W-O bond formed by the B-site and oxygen ion longer and the Li-O bond shorter, and the difference between the eight octahedral around the A-site is reduced, increasing the symmetry of the A-site. Local symmetry was successfully modulated by changing the Eu3+ concentration to control the Y/B ratio of Dy3+ and the R/O ratio of Eu3+ and smoothly achieved (0.382, 0.373) warm white light color coordinate. The phosphor has excellent thermal stability and still has 92.3% intensity at 475 K. The above results show that the wavelength composition of the luminescence is tunable by changing the symmetry of the environment in which the doped ions are located. It applies to single hosts for the regulation of white light emission. 相似文献
4.
Australia's electricity market is rapidly adding renewable energy generation. Utility-scale batteries could have a major role in facilitating these transitions; however, their deployment is still largely state-subsidized. We summarize the current and future roles for batteries from a legal-economic perspective in the context of Australia's electricity market framework. We find that the future of batteries in Australia is not only a function of the large-scale deployment of renewables, their cost development and the comparative future cost of competing gas turbines but also of national electricity market and state policy reforms focusing on reliability. 相似文献
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《Ceramics International》2021,47(20):28521-28527
Layered O3 type oxides exhibit promising prospects as high-performance cathodes for sodium-ion batteries (SIBs) due to their low cost and high theoretical capacities. Nevertheless, the intrinsic surface composition and bulk structure degradation upon cycling presents a huge obstacle to stable sodium-ion storage/transportation. Besides, the effective surface decoration on layered O3 oxides is still challenging through conventional wet chemical route owing to their extraordinarily high surface sensitivities. Herein, a typical O3 type layered oxide of NaNi0.5Mn0.5O2 (NNMO) was selected and successfully encapsulated by precisely controlled Al2O3 layers via atomic layer deposition (ALD) technology. With the optimally controlled Al2O3 thickness of 3 nm, the surface regulated NNMO delivers a highly reversible capacity of 73.6 mA h g-1, with a significantly improved capacity retention of 68.0% after 300 cycles at 0.5 C, and a superior rate capability of 65.8 mA h g-1 at 10 C. Further air sensitivity tests demonstrate that the protective layer could effectively mitigate the generation of sodium-based impurities on NNMO, and reduce the surface sensitivities. Both chemical and electrochemical aging tests confirm the contribution of Al2O3 coating layer in alleviating ion dissolution as well as stabilizing the structure and morphology of NNMO. Based on regulating the surface of O3 type layered oxides utilizing ALD technique, this work supplies an effective and facile strategy to overcome the challenges from fast structure degradation and electrochemical property decay, which not only highlights the significance and effectiveness of surface engineering in secondary batteries, but also sheds light on accurate interface construction and regulation for active electrode materials, particularly for those sensitive to ambient atmosphere. 相似文献
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亨廷顿病(Huntington's disease, HD)是神经退行性疾病(neurodegenerative disorders)中一种单基因遗传病,由亨廷顿基因(the huntingtin gene, HTT)第一个外显子中的CAG三核苷酸序列重复扩增引起,尚无法治愈。HTT编码的蛋白产物被称为亨廷顿蛋白(Huntingtin protein, Htt)。突变亨廷顿蛋白(mutated huntingtin protein, mHtt)容易形成聚集体,具有毒性,导致一系列细胞学异常和神经元功能障碍。microRNA(miRNA)在基因转录后水平调控中起重要作用,其表达的改变与HD病理过程有关,成为治疗HD的潜在生物标志物。近年来,对一些特定miRNA在HD中调控机制及靶基因预测方面的研究可为HD提供潜在的治疗方法。本文就miRNA在HD中的相关研究进展进行综述。 相似文献
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