Preparation and Properties of MnO_2 /polyaniline Composite

以δ-MnO2为前驱体,通过酸处理后引入苯胺并聚合,得到了MnO2/聚苯胺复合材料。经XRD分析表明,在本研究条件下,经酸处理后的δ-MnO2晶型由δ型转变为α型,而在随后的苯胺引入及其聚合步骤中MnO2晶型均不再改变。以200mA·g-1的电流进行恒电流充放电性能测试,结果显示,MnO2/聚苯胺复合材料的充放电容量达到160.2mA·g-1,与酸处理后得到的α-MnO2接近(160.9mA·g-1),但比前驱体δ-MnO2高(125.8mA·g-1);更为重要的是,MnO2/聚苯胺复合材料与前驱体及酸处理得到的样品相比,其循环性能得到了较大的提高。MnO2 /polyaniline composite was prepared by polymerization of aniline in α-MnO2 from the acid-treating precursor of δ-MnO2. XRD results showed that during acid treatment the precursor of δ-MnO2 was transformed into α-MnO2, and this in α-MnO2 polymorph kept unchanged in the subsequent processes, as intercalation and polymerization of aniline. Comparison of charge-discharge performances among the precursor, its acid-treated form and the final composite, showed that at current density of 200 mA·g-1 the discharge capacity of the composite was 160.2 mA·g-1, which is close to that of the acid-treated material (160.9 mA·g-1) but higher than that of the precursor (125.8 mA·g-1). More important, the MnO2 /polyaniline composite showed a much better cyclic performance than the precursor and its acid-treated form.福建省高新技术重点项目(No2005H071);; 三明市重点科技项目(No2005-G-9

Preparation and properties of MnO2/polyaniline composite

MnO2/polyaniline composite was prepared by polymerization of aniline in alpha-MnO2 from the acid-treating precursor of delta-MnO2. XRD results showed that during acid treatment the precursor of delta-MnO2 was transformed into alpha-MnO2, and this in alpha-MnO2 polymorph kept unchanged in the subsequent processes, as intercalation and polymerization of aniline. Comparison of charge-discharge performances among the precursor, its acid-treated form and the final composite, showed that at current density of 200 mA . g(-1) the discharge capacity of the composite was 160.2 mA.g(-1), which is close to that of the acid-treated material (160.9 mA . g(-1)) but higher than that of the precursor (125.8 mA . g(-1)). More important, the MnO2/polyaniline composite showed a much better cyclic performance than the precursor and its acid-treated form

国内8款常用植物识别软件的识别能力评价

随着智能手机和人工智能技术的发展,以手机app为载体的植物识别软件慢慢走进公众生活、科普活动和科研活动的各个方面。植物识别app的识别正确率是决定其使用价值和用户体验的关键因素。目前,国内应用市场上有许多植物识别app,它们的开发目的和应用范围各异,软件本身的关注点、数据库来源、算法、硬件要求也存在很大差异。对于不同人群,植物识别app有不同的意义,如对于科研人员来说,识别能力强的app是提高效率的一大工具;对植物爱好者来说,具一定准确率的识别app可以作为入门的工具。因此,对各app的识别能力进行分析与评价显得尤为重要。本文选取了8款常用的app,分别对400张已准确鉴定的植物图片进行识别,其中干旱半干旱区、温带、热带和亚热带4个区各选取100张。这些图片共计122科164属340种,涵盖了乔木、灌木、草本、草质藤本和木质藤本5种生长型,包含23种国家级保护植物。种、属、科准确识别正确分别计4分、2分、1分,以此标准对软件识别能力按总得分进行排序,正确率得分由高到低依次为花帮主、百度识图、花伴侣、形色、花卉识别、植物识别、发现识花、微软识花