Microtopography of microbiotic crusts on the Colorado Plateau, and distribution of component organisms

We analyzed the microtopography of microbiotic soil crusts at 3 sites on the Colorado Plateau of southern Utah and investigated distributions of cyanobacteria and several lichens in distinctive microhabitats created by this topography. At all 3 sites the long axes of linear soil mounds were oriented nonrandomly in a NNW—SSE direction. The conspicuous and consistent orientation of soil mounds may result from a combination of physical and biotic processes. Subtle differences across sites in mound orientation and organismal distribution suggest that these variables may be useful in comparing disturbance histories of crusts retrospectively. Differences in colonization frequencies, abundances, and distributions of microorganisms comprising the crusts, as a function of mound aspect or exposure, suggest that these organisms are associated with particular aspects due to distinctive and favorable microhabitats on these exposures. Polysaccharide sheath material, deposited by cyanobacteria, and associated filaments occurred in greater quantities on ENE than WSW mound exposures, and cover by Collema spp. lichens exhibited the same pattern. Colonization of mounds by common lichen species occurred significantly more frequently on ENE than WSW mound aspects at 2 of 3 sites. In contrast, the 3 most common lichen species, aside from Collema spp., did not exhibit a tendency for greater cover on ENE than WSW mound aspects. Physiological differences between gelatinous cyanolichens and green-algal lichens may explain the different distributional patterns of Collema spp. and the 3 other lichens.     

2019年熔盐电解法制备硅基能源材料热点回眸

介绍熔盐电解法制备硅材料及其在能源领域的应用,并回顾其2019年的基础研究进展。熔盐电解方法可以在较温和的温度下通过电化学还原氧化硅实现硅纳米材料的大规模制备,得到的硅纳米材料纯度和形貌可控,能够用于硅基光伏材料以及锂离子电池负极材料。     

烯-二炔”模型化合物前体：6-硫杂-13-氧杂双环［9．3．0］-3，8-十四二炔的合成

以顺 1,2 ,3,6 四氢邻苯二甲酸酐为原料 ,经还原 ,羟基保护 ,双键臭氧化开环 ,Wittig反应 ,双炔化 ,酯化 ,二醇化 ,二磺酸酯化 ,硫化 ,醇缩合共十步 ,合成了“烯 二炔”前体物 :6 硫杂 13 氧杂双环 [9.3.0 ] 3,8 十四二炔 .该合成法收率较高 ,反应条件温和 ,新化合物 ( 8) ,( 10 ) ,( 11)经元素分析 ,核磁 ,红外 ,质谱确证结构 .