生物质纤维素基多功能材料构建及其在新型能量存储方面的应用

生物质材料细胞壁物质的高效分离及功能化直接关系着废弃生物质的高值化应用。作为生物质材料细胞壁的三大组分之一,纤维素纳米纤丝已经被广泛用于构建独特纳米结构和功能的复合材料如三维结构气凝胶、自修复水凝胶、纳米微晶光子膜、光敏感织物等。探索一条生物质纤维素高值化、实用化发展路径显得尤为重要,本文围绕生物质纳米纤维素的分离提取和功能材料的构筑及其在新型能源存储方面的应用进行论述。首先,简要叙述当前纳米纤维素的化学结构及其作为多功能材料结构单元的优势,并从实验条件、环保、经济、纤维得率与质量的角度分析了生物基纳米纤维素分离制备方法的发展历程和优缺点;然后,介绍了纳米纤维素基纤维、薄膜、气凝胶、碳气凝胶的微/纳米结构、化学键、力学性能在热管理器件如建筑制冷器、太阳驱动式水蒸发器中太阳能的散射与吸收、红外发射、水分的吸收与传导和电化学能源储存中柔性电极的设计、亲锂型隔膜及碳基集流体等功能材料的构建过程中所发挥的作用。最后,从生物质材料的特异性结构的利用、组分的提取分离与转化、复合材料构建角度对纳米纤维素的未来研究方向进行了展望。

Smallholder Adoption of Soil and Water Conservation Practices in Northern Ghana

Both governmental and non-governmental organizations are engaged in the promotion of soil and water conservation practices in Northern Ghana, but adoption is believed to be low. This study thus examines the determinants of conservation practices adoption by farming households in the area. Data for the study were collected from 445 households located in 15 communities in Northern Ghana. Univariate, bivariate and multivariate probit models were used to analyse the decision to adopt six conservation practices in the area. Results show that the major determinants of adoption are plot and cropping characteristics such as location; and socio-economic and institutional variables such as number of contacts with extension officers, membership in farmer association and distance to major market. A policy implication of the study is the strengthening of extension service in the area to significantly boost conservation adootion.