Construction of Synchronous-Deposition K Metal Anodes Via Modulation of Ion/Electron Transport Kinetics for High-Rate and Low-Temperature K Metal Batteries.

The construction of conductive scaffolds is demonstrated to be an ideal strategy to alleviate the volume expansion and dendrite growth of K metal anodes. Nevertheless, the heterogeneous top-bottom deposition behavior caused by incompatible electronic/ionic conductivity of three-dimensional (3D) skeleton severely hinders its application. Here, a K2 Se/Cu conducting layer is fabricated on the Cu foam so as to enhance ionic transport and weaken electronic conductivity of the skeleton. Then, an excellent simultaneous deposition behavior of K metal inside the host is obtained for the first time via tuning fast ionic transport and low electronic conductivity. The simultaneous deposition mode can not only utilize the entire 3D structure to accommodate the volume expansion during K deposition but also avoid the formation of K dendrites at high current and ultra-low temperature. Consequently, the symmetric cells present a long cycle lifespan over 1000 h with a low deposition overpotential of 80 mV at 1 mA cm-2 . Furthermore, the full cell matching with the perylene-tetracarboxylic dianhydride (PTCDA) cathode presents an outstanding cycle lifespan over 600 cycles at 5 C at -20°C. The proposed simultaneous deposition strategy provides a new design direction for the construction of dendrite-free K metal anodes.

High-efficient lignin-based polymerizable macromolecular photoinitiator with UV-blocking property for visible light polymerization.

Developing high-efficient visible light macromolecular photoinitiator (macro PI) with excellent initiation performance, low migration, high biosafety and multi-function is beneficial to broaden the application of photopolymer. Lignin contains chromophores which could generate free radicals under light irradiation. In this study, a lignin-based polymerizable macro PI (DAL-11ene-amine) was designed and synthesized through covalent grafting 10-undecenoyl chloride (11ene) and hydrogen donor 4-(dimethylaminobenzoic acid) ethyl ester (EDAB) into dealkaline lignin (DAL) skeleton. The structure of DAL-11ene-amine was characterized by UV-vis, FTIR, 1H NMR, GPC, and 31P NMR spectra. Under the irradiation of a 405 nm LED, DAL-11ene-amine can directly produce active species and initiate the polymerization of acrylate monomers or thiol-ene click reaction. The photoinitiation efficiency of DAL-11ene-amine is higher than that of DAL-11ene or the two-component combination of DAL-11ene and EDAB. Using DAL-11ene-amine as PI, the prepared polymer films exhibit excellent UV-blocking property. With only 0.5 wt% addition of DAL-11ene-amine, nearly 100% of UVB + UVC and the most of UVA can be blocked by the films. Moreover, DAL-11ene-amine exhibits higher migration stability and biosafety because it can be covalently linked into polymer cross-linking networks. The results indicate that DAL-11ene-amine has great application potentials in preparing environmentally friendly UV-blocking films and biosafety coatings.

Da rotatividade migratória à baixa migração: uma análise dos padrões da mobilidade populacional no Brasil de 1995-2000 / From rotative to low migration patterns: an analysis of 1995-2000 patterns of population mobility in Brazil / /De la rotación migratoria a la baja migración: un análisis de los patrones de la movilidad poblacional en Brasil de 1995-2000

Este trabalho propõe uma metodologia de classificação dos municípios brasileiros conforme a característica migratória, tendo como base as informações disponíveis no Censo Demográfico de 2000. Foram aplicadas análises multivariadas de redução e classificação de dados sobre um conjunto de variáveis selecionadas que descrevem a forma como os 5.507 municípios se articulam na rede migratória brasileira. Primeiramente, aplicou-se uma análise de componentes principais com a finalidade de reduzir o conjunto de variáveis originais em componentes não correlacionados entre si. Posteriormente, estes componentes foram empregados numa análise classificatória de cluster com o objetivo de estabelecer uma tipologia migratória das localidades em estudo. Os resultados mostraram que há importantes diferenciais na inserção dos municípios na rede migratória, na qual existe um grande número de lugares pouco conectados em contraste com um número pequeno de pontos que experimentam fortes conexões, e nos quais a população circula rapidamente. A classificação aponta para a existência de novas categorias de lugares, além das definições clássicas de atração e repulsão, como a rotatividade migratória.

The authors propose a method for classifying the 5507 municipalities in Brazil according to their characteristics of migration phenomena, as shown in the data now available from the 2000 National Brazilian Census. Multivariate classifications for data reduction and classification analysis were carried out on a set of selected variables that describe how the municipalities in the country are articulated with the overall Brazilian migration network. First a central component analysis was applied in order to reduce the set of original variables into a new set of uncorrelated components. Next these components were used in a classificatory cluster analysis with the purpose of establishing a migration typology for the locations being studied. The results showed that there are great differences among municipalities in their participation in the migration network. There are many municipalities with weak ties with the migration network and a few areas with strong ties, where the populations are very mobile. We have called these municipalities "rotative locations." This classification indicates the existence of new categories of territory beyond the classical definitions of attraction and repulsion, one example being these rotative areas.

Este trabajo propone una metodología de clasificación de los municipios brasileños según la característica migratoria, utilizando como base las informaciones disponibles en el Censo Demográfico de 2000. Se aplicaron análisis multivariantes de reducción y clasificación de datos sobre un conjunto de variables seleccionadas que describen la forma en la que los 5.507 municipios se articulan en la red migratoria brasileña. En primer lugar se aplicó un análisis de componentes principales con la finalidad de reducir el conjunto de variables originales en componentes no correlacionados entre sí. Posteriormente, estos componentes fueron utilizados en un análisis clasificatorio de cluster, con el objetivo de establecer una tipología migratoria de las localidades en estudio. Los resultados mostraron que hay importantes diferenciales en la inserción de los municipios en la red migratoria, en la que existe un gran número de lugares poco conectados en contraste con un número pequeño de puntos que experimentan fuertes conexiones, y en los cuales la población circula rápidamente. La clasificación señala la existencia de nuevas categorías de lugares, además de las definiciones clásicas de atracción y repulsión, como la rotación migratoria.