Characterization of Unusually Large “Pseudo-Single Crystal” of β-Nickel Hydroxide

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Influence of the Quantum Capacitance on Electrolyte Conductivity through Carbon Nanotubes

In recent experiments, unprecedentedly large values for the conductivity of electrolytes through carbon nanotubes (CNTs) have been measured, possibly owing to flow slip and a high pore surface charge density whose origin remains debated. Here, we model the coupling between the CNT quantum capacitance and the classical electrolyte-filled pore one and study how electrolyte transport is modulated when a gate voltage is applied to the CNT. Our work shows that under certain conditions the quantum capacitance is lower than the pore one due to the finite quasi-1D CNT electronic density of states and therefore controls the CNT surface charge density that dictates the confined electrolyte conductivity. The dependence of the computed surface charge and conductivity on reservoir salt concentration and gate voltage is thus intimately related to the electronic properties of the CNT. This approach provides key insight into why metallic CNTs have larger experimentally measured conductivities than semiconducting ones

Global patterns and environmental drivers of forest functional composition

Abstract: Aim: To determine the relationships between the functional trait composition of forest communities and environmental gradients across scales and biomes and the role of species relative abundances in these relationships. Location: Global. Time period: Recent. Major taxa studied: Trees. Methods: We integrated species abundance records from worldwide forest inventories and associated functional traits (wood density, specific leaf area and seed mass) to obtain a data set of 99,953 to 149,285 plots (depending on the trait) spanning all forested continents. We computed community‐weighted and unweighted means of trait values for each plot and related them to three broad environmental gradients and their interactions (energy availability, precipitation and soil properties) at two scales (global and biomes). Results: Our models explained up to 60% of the variance in trait distribution. At global scale, the energy gradient had the strongest influence on traits. However, within‐biome models revealed different relationships among biomes. Notably, the functional composition of tropical forests was more influenced by precipitation and soil properties than energy availability, whereas temperate forests showed the opposite pattern. Depending on the trait studied, response to gradients was more variable and proportionally weaker in boreal forests. Community unweighted means were better predicted than weighted means for almost all models. Main conclusions: Worldwide, trees require a large amount of energy (following latitude) to produce dense wood and seeds, while leaves with large surface to weight ratios are concentrated in temperate forests. However, patterns of functional composition within‐biome differ from global patterns due to biome specificities such as the presence of conifers or unique combinations of climatic and soil properties. We recommend assessing the sensitivity of tree functional traits to environmental changes in their geographic context. Furthermore, at a given site, the distribution of tree functional traits appears to be driven more by species presence than species abundance