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991.
《International Journal of Hydrogen Energy》2021,46(56):28686-28699
Thermal energy storage systems based on metal hydrides can be a solution for preheating fuel cells (FCs). They can provide thermal energy at temperatures below −20 °C during startup, while heat at 50 °C during operation is sufficient for regeneration. The challenge of such a system in mobile applications is the final weight specific thermal power. In this study, a reactor design based on additive manufacturing techniques for ~300 g of metal hydride is presented. Here, a reactor (passive) to hydride (active) mass ratio of 0.97 is realized, still reaching high weight specific thermal power of up to 2.1 kW/kgMH at −20 °C and 8 bar (LmNi4.91Sn0.15). Considering the example of preheating a FC from −20 °C in ~120 s, the performance of LaNi5 and LmNi4.91Sn0.15 is studied. While LaNi5 requires higher regeneration temperatures than LmNi4.91Sn0.15 (>40 °C compared to >20 °C), its performance is less sensitive to operative variations due to its nearly ideal thermodynamic characteristic. 相似文献
992.
Bo Yang Chunyuan Zeng Long Wang Yinyuan Guo Guanghua Chen Zhengxun Guo Yijun Chen Danyang Li Pulin Cao Hongchun Shu Tao Yu Jiawei Zhu 《International Journal of Hydrogen Energy》2021,46(44):22998-23012
It is essential to develop an accurate model of proton exchange membrane fuel cell (PEMFC) for a reliable operation and analysis, in which unknown parameters usually need to be determined. The inherent nonlinear, strong coupling, and diversification of PEMFC model seriously hinder traditional methods to identify the parameters. For the sake of overcoming these thorny obstacles, Levenberg-Marquardt backpropagation (LMBP) algorithm based on artificial neural networks (ANNs) is proposed for PEMFC parameter identification. Furthermore, the performance of LMBP is thoroughly evaluated and compared with four typical meta-heuristic algorithms under three cases. Simulation results indicate that LMBP performs a higher accuracy and faster speed for parameter identification. In particular, accuracy and convergence speed can achieve as much as 99.8% and 95.9% growth via LMBP, respectively. 相似文献
993.
Yihan Ling Lu Liu Shijie Zhou Yang Yang Hui Zhu Hui Chen M.H. Paydar Shaorong Wang 《International Journal of Hydrogen Energy》2021,46(53):27149-27155
Ruddlesden?Popper layered oxide, La0.25Sr2.75FeNiO7-δ (LSFN) is evaluated as a potential electrode material for symmetrical solid oxide fuel cells. The in-situ formation of Ni–Fe alloy nanoparticles on the LSFN surface in reducing atmosphere can be believed to enhance the activity towards hydrogen oxidation reaction. LSFN exhibit maximum conductivity of 221.2 S/cm and 0.206 S/cm in air and hydrogen environment. Furthermore, LSFN is mixed with GDC powder to form a composite electrode for symmetric solid oxide fuel cells (SSOFC). Results show that with the combination of GDC, the maximum power density of YSZ-based SSOFC enlarges from 232.3 mW cm?2 to 348.5 mW cm?2, and related polarization resistance reduces from 0.359 Ω cm2 to 0.108 Ω cm2. The improved performance is attributed to the enlarged triple-phase boundary with the mixing of GDC. In addition, YSZ-based SSOFC with the LSFN-GDC composite electrode shows a stable performance in intermediate-temperature SSOFCs within 200 h, which indicates that LSFN-GDC composite material is a prospective symmetrical electrode for SSOFC. 相似文献
994.
Ana Belén Bautista-Ortín Rim Ben Abdallah Liliana del Rocío Castro-López María Dolores Jiménez-Martínez Encarna Gómez-Plaza 《International journal of molecular sciences》2016,17(1)
The transference and reactivity of proanthocyanidins is an important issue that affects the technological processing of some fruits, such as grapes and apples. These processes are affected by proanthocyanidins bound to cell wall polysaccharides, which are present in high concentrations during the processing of the fruits. Therefore, the effective extraction of proanthocyanidins from fruits to their juices or derived products will depend on the ability to manage these associations, and, in this respect, enzymes that degrade these polysaccharides could play an important role. The main objective of this work was to test the role of pure hydrolytic enzymes (polygalacturonase and cellulose) and a commercial enzyme containing these two activities on the extent of proanthocyanidin-cell wall interactions. The results showed that the modification promoted by enzymes reduced the amount of proanthocyanidins adsorbed to cell walls since they contributed to the degradation and release of the cell wall polysaccharides, which diffused into the model solution. Some of these released polysaccharides also presented some reactivity towards the proanthocyanidins present in a model solution. 相似文献
995.
996.
AbstractThis review collects recent five-year publications on low bandgap semiconducting polymers, which are composed of electron donor (D) and electron acceptor (A) units, exhibiting the power conversion efficiency (PCE) higher than 6%. When the photovoltaic performances of different types of D−A semiconducting copolymers are compared after the copolymers are classified into several categories according to the type of A-units, it is realized that diketopyrrolopyrrole (DPP)-based copolymers exhibit high JSCs owing to low bandgaps and low VOCs due to high-lying HOMO levels, while thienopyrroledione (TPD)-based copolymers exhibit high VOCs due to their deep HOMO levels and low JSCs because of wide bandgaps. Benzothiadiazole- and thienothiophene-based copolymers show intermediate values of VOC and JSC between DPP- and TPD-based ones. For further enhancement of photovoltaic performance, DPP-based copolymers may be designed to have deeper HOMO level with the minimum widening of bandgap while TPD-based polymers may be designed to have lower bandgap with the minimum rise of HOMO level. Hence, the energy level tuning must be considered so as to minimize the adverse effect. 相似文献
997.
Minh Truong Xuan Nguyen Minh-Kha Nguyen Phuong Thi Thuy Pham Ha Ky Phuong Huynh Son Truong Nguyen 《International Journal of Hydrogen Energy》2021,46(5):3909-3921
One-dimensional (1D) metal-coated Pd structures are efficient catalysts for the ethanol electro-oxidation and promising strategy for minimizing the Pd-loading toward commercialization of direct ethanol fuel cells (DEFCs). Herein, the decorated and core-shell architectures of a novel Pd coating on Ag nanowires (PdAg-NWs) are controllable by a two-step polyol method based on the galvanic replacement reaction. The integration of uniform shell with a low Pd concentration and partial hollow structure onto 1D PdAg-NWs exhibits the highest efficiency for ethanol oxidation reaction (EOR) in alkaline solution. In comparison with Pd nanoparticles (PdNPs/C), the PdAgNWs/C performes 11 times superior EOR activity, and the onset potential shifts 80 mV negatively. The presence of Ag in PdAg-NWs enhances the absorption capacity of ethanol molecules and hydroxyl ions on the active sites, and improves the catalyst tolerance to CO-like intermediates, making them a potential anodic catalyst for DEFCs. 相似文献
998.
We fabricate the thinnest (1.3 μm) and lightest (3.6 g/m2) solar cells yet demonstrated, with weight-specific power exceeding 6 W/g, in order to illustrate the lower limits of substrate thickness and materials use achievable with a new processing paradigm. Our fabrication process uniquely starts with growth of an ultra-thin flexible polymer substrate in vacuum, followed by deposition of electrodes and photoactive layers in situ. With this process sequence, the entire cell—from transparent substrate to active layers to encapsulation—can be fabricated at room temperature without solvents and without breaking vacuum, avoiding exposure to dust and other contaminants, and minimizing damage risk associated with handling of thin substrates. We use in situ vapor-phase growth of smooth, transparent, and flexible parylene-C films to produce ultra-thin, lightweight molecular organic solar cells as thin as 2.3 μm including encapsulation with a second parylene-C film. These parylene-based devices exhibit power conversion efficiencies and fabrication yields comparable to glass-based cells. Flexible solar cells on parylene membranes can be seamlessly adhered to a variety of solid surfaces to provide additive solar power. 相似文献
999.
1000.