RESUMEN

Aqueous sodium-ion batteries (SIBs) represent a class of green electrochemical technology for large-scale storage of sustainable energies such as wind power and solar radiation, owing to their low cost, environmental friendliness, and reliable safety. However, there is still lack of available anode materials for aqueous SIBs. Herein, nanocrystal-assembled porous Na3 MgTi(PO4 )3 aggregates are reported as novel anode material for aqueous SIBs. The crystal structure, morphological features, and electrochemical properties have been analyzed with X-ray diffraction, scanning electron microscopy, transition electron microscopy, cyclic voltammetry, and charge/discharge measurements. As revealed, the material possesses a porous nanostructure composed of 5 nm nanocrystals and mesoporous channels. During Na-insertion/extraction, it undergoes a one-step single-phase reaction mechanism through reversible electrochemistry of the Ti4+ /Ti3+ redox couple, showing a rechargeable capacity of 54 mAh g-1 and an average working potential of -0.63 V (vs. Ag/AgCl) at 0.2 C. More importantly, good rate capacity (33 mAh g-1 at 4 C) and excellent cycling performance (94.2 % capacity retention after 100 cycles at 0.5 C) are achieved due to the unique porous nanostructure and robust compositional framework. The finding in this work would create new opportunities for design of low-cost, long-cycling aqueous SIBs.

RESUMEN

Standing trees decay often causes vast loss of timber resources. To investigate the correlations between the standing trees decay and the site conditions is of importance to scientifically and reasonably manage forests and to decrease wood resources loss. By using Resistograph and meter ruler, a measurement was made on the decay degree of the trunk near root and the diameter at breast height (DBH) of 15 mature Korean pine standing trees in a Korean pine-broadleaved mixed forest in Xiao Xing' an Mountains in May, 2011. In the meantime, soil samples were collected from the root zones of standing trees and the upslope and downslope 5 meters away from the trunks, respectively. Five physical-chemical properties including moisture content, bulk density, total porosity, pH value, and organic matter content of the soil samples were tested. The regression equations concerning the trunk decay degree of the standing trees, their DBH, and the 5 soil properties were established. The results showed that the trunk decay degree of the mature Korean pine standing trees had higher correlations with the bulk density, total porosity, pH value, and organic matter content (R = 0.687), and significant positive correlation with the moisture content (R = 0.507) of the soils at the root zones of standing trees, but less correlation with the 5 properties of the soils at both upslope and downslope 5 meters away from the trunks. The trunk decay degree was decreased when the soil moisture content was below 18.4%. No significant correlation was observed between the trunk decay degree of mature Korean pine standing trees and the tree age.

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RESUMEN

The insecticidal active components in Juglans mandshurica Maxim leaves were extracted by conventional method. The alcohol extract and its chloroform-extraction phase showed insecticidal activities in contact toxicity and stomach toxicity against Lymantria dispar L. and Mamestra brassicae L. larvae. When the concentration of the extract was above 10 g x L(-1), the corrected mortality was higher than 50% 5 days after applying the extract. Alcohol extract had higher insecticidal activities than its chloroform-extraction phase. The GC-MS analysis on the active components in the chloroform-extraction phase showed that the main component was juglone (5-hydroxy-1,4-naphthalenedione), and the others were 2,2'-methylenebis-6-(1,1-dimethylethyl)-4-methyl-diphenol and 2-methoxy-4-vinylphenol.

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