Abstract
Anodic oxygen evolution reaction (OER) is recognized as kinetic bottleneck in water electrolysis. Transition metal sites with high valence states can accelerate the reaction kinetics to ...offer highly intrinsic activity, but suffer from thermodynamic formation barrier. Here, we show subtle engineering of highly oxidized Ni
4+
species in surface reconstructed (oxy)hydroxides on multicomponent FeCoCrNi alloy film through interatomically electronic interplay. Our spectroscopic investigations with theoretical studies uncover that Fe component enables the formation of Ni
4+
species, which is energetically favored by the multistep evolution of Ni
2+
→Ni
3+
→Ni
4+
. The dynamically constructed Ni
4+
species drives holes into oxygen ligands to facilitate intramolecular oxygen coupling, triggering lattice oxygen activation to form Fe-Ni dual-sites as ultimate catalytic center with highly intrinsic activity. As a result, the surface reconstructed FeCoCrNi OER catalyst delivers outstanding mass activity and turnover frequency of 3601 A g
metal
−1
and 0.483 s
−1
at an overpotential of 300 mV in alkaline electrolyte, respectively.
International Thermonuclear Experimental Reactor (ITER) static magnetic field (SMF) test facility requires a dc power supply with low voltage, high current, and low harmonics under high power ...density. Due to the limitation of switching loss, there is a contradiction between the output current capability and the output ripple. Large output current usually leads to low switching frequency, and low switching frequency will generate a large number of harmonics. To solve the problems, a topology based on the interleaving parallel buck converter is used and tested in this article. Moreover, the topology is realized with only a small number of switching metal-oxide-semiconductor field-effect transistors (MOSFETs). This article introduces the system design scheme and control method in detail. The analysis of harmonic and simulation is carried out. The validity of the proposed scheme and control strategy was confirmed by experiments, and the power supply system can supply a large current of 12.23 kA and has the ability of low ripple.
In the present study, the toxicity and bioaccumulation kinetics of arsenate in two green algae Chlamydomonas reinhardtii and Scenedesmus obliquus under phosphate-enriched (+P) and limited (−P) ...conditions were investigated. P-limitation was found to aggravate arsenate toxicity and S. obliquus was more tolerant than C. reinhardtii. Such phosphate-condition-dependent or algal-species-specific toxicity difference was narrowed when the relative inhibition of cell growth was plotted against intracellular arsenate content instead of its extracellular concentration. The discrepance was further reduced when the intracellular ratio of arsenic to phosphorus was applied. It suggests that both arsenate bioaccumulation and intracellular phosphorus played an important role in arsenate toxicity. On the other hand, arsenate uptake was induced by P-limitation and its variation with ambient arsenate concentration could be well fitted to the Michaelis–Menten model. Arsenate transporters of S. obliquus were found to have a higher affinity but lower capacity than those of C. reinhardtii, which explains its better regulation of arsenate accumulation than the latter species in the toxicity experiment. Further, arsenate depuration was facilitated and more was transformed to arsenite in C. reinhardtii or under –P condition. Intracellular proportion of arsenite was also increased after the algae were transferred from the long-term uptake media to a relatively clean solution in the efflux experiment. Both phenomena imply that algae especially the sensitive species could make physiological adjustments to alleviate the adverse effects of arsenate. Overall, our findings will facilitate the application of algae in arsenate remediation.
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► Phosphate limitation induced arsenate uptake, efflux, transformation and toxicity. ► Scenedesmus had a better regulation of arsenate accumulation and was more tolerant. ► Intracellular ratio of arsenic to phosphorus could best predict arsenate toxicity.
In recent years, a large number of studies have shown that the subcellular localization of long non-coding RNAs (lncRNAs) can bring crucial information to the recognition of lncRNAs function. ...Therefore, it is of great significance to establish a computational method to accurately predict the subcellular localization of lncRNA. Previous prediction models are based on low-level sequences information and are troubled by the few samples problem. In this study, we propose a new prediction model, GM-lncLoc, which is based on the initial information extracted from the lncRNA sequence, and also combines the graph structure information to extract high level features of lncRNA. In addition, the training mode of meta-learning is introduced to obtain meta-parameters by training a series of tasks. With the meta-parameters, the final parameters of other similar tasks can be learned quickly, so as to solve the problem of few samples in lncRNA subcellular localization. Compared with the previous methods, GM-lncLoc achieved the best results with an accuracy of 93.4 and 94.2% in the benchmark datasets of 5 and 4 subcellular compartments, respectively. Furthermore, the prediction performance of GM-lncLoc was also better on the independent dataset. It shows the effectiveness and great potential of our proposed method for lncRNA subcellular localization prediction. The datasets and source code are freely available at https://github.com/JunzheCai/GM-lncLoc .
To overcome the poor mechanical performance of methyltrimethoxysilane (MTMS) aerogels and the low thermal stability of polyvinyl alcohol (PVA), the PVA/MTMS aerogel composites (PMAC) were ...successfully prepared through a facile impregnation process. It finds that the PVA concentration has a great influence on the physicochemical properties of the PMAC, which has been investigated in detail. It further turns out that the density (0.081 ~ 0.152 g/cm
3
) increases linearly along with the PVA concentration, while the thermal conductivity (32.9 ~ 51.7 mW/m/K) increases monotonously first and then keeps almost unchanged. The hydrophilicity of PMAC can be tailored by adjusting the PVA concentration. Compared with the pure MTMS aerogel and PVA, the thermal analysis reveals that the PMAC shows an improved thermal stability. Although the physical combination is verified between the MTMS aerogel and PVA, the mechanical performance of the PMAC is still significantly enhanced with the Young’s modulus and compressive strength reaching up to 20.35 MPa and 970.33 kPa, respectively. All these results suggest that the introduction of PVA into MTMS aerogel is feasible and effective for acquiring better performance for the aerogel composites, which contributes to extending their potential applications.
Large eddy simulation (LES) has the potential to predict turbulent combustion phenomena in modern practical combustors. As errors from sub-grid models may be comparable to the numerical errors in the ...LES approach, mitigating the impact of the numerical errors is as important as constructing accurate sub-grid models. Therefore, a low-dissipative, structure-preserving ROUND (Reconstruction Operators on Unified Normalized-variable Diagram) scheme is tested for the LES of reacting flows in this study. The high efficiency of this scheme is demonstrated by evaluating its accuracy, central processing unit cost, and structure-preserving property by simulating the convection–diffusion process of a passive scalar. Simulations of two bluff body stabilized flames are studied using this scheme. For low turbulence intensity, the current scheme improves the numerical resolution of the instantaneous and averaged flow fields. The prediction of flow statistics is also improved by the ROUND schemes compared to the conventional schemes. Moreover, the ROUND schemes preserve the axisymmetry of the averaged flow better than the conventional schemes for the cases investigated here. For the high turbulence intensity case, the ROUND scheme avoids nonphysical numerical oscillations. The flow and flame statistics obtained using this scheme compare well with measurements. Therefore, this work demonstrates the advantages of using ROUND schemes for LES of reacting flows.
In this article, we report the synthesis of a MOF containing multiple C&z.dbd;C bonds geometrical features by adjusting the reactant ratio of the synthetic system. The photochemical addition studies ...revealed that the ligand 1,4-bis2-(4-pyridyl)ethenylbenzene can undergo photoisomerization under UV irradiation, and the
angle between the C&z.dbd;C bonds can be changed by about 85°, so that the C&z.dbd;C pairs that do not conform to Schmidt's rule can be transformed into the conforming state, and then the 2 + 2 photoaddition can occur. We found that the
angle range suitable for photoaddition includes not only the 0-15° range, but also the potential 85 ± 15° range. Furthermore, it is not the C&z.dbd;C pair that best conforms to Schmidt's rule that gives priority to the photoaddition, but the one that enables the lowest total energy in the crystal to occur.
The angle range suitable for topological chemical photoaddition has been clarified.
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