颗粒物悬浮体系中聚合铝凝聚絮凝形态表征 (Ⅰ):Al-Feron法的应用研究

应用Ａｌ－Ｆｅｒｒｏｎ法于悬浮体系中聚合铝的形态分布表征，对其中的主要影响因素进行探讨，就不同碱化度聚合铝的形态分析进行实例研究．结果表明，混合方式对Ａｌ－Ｆｅｒｏｎ法的应用具有一定的影响作用．比色管混合测得Ａｌａ为２１．５４％，低于磁力搅拌方式结果（２４．５２％，２５．２２％，２５．０６％）．应用磁力搅拌方式可以获取较好的重复性与更多初期反应信息．颗粒物的存在对反应的影响主要取决于其浓度与粒度分布，成一定线性关系，可以从中加以扣除．在本实验范围内因其溶解所产生的影响可以忽略不计．对多个碱化度聚合铝的实例研究表明，Ａｌ－Ｆｅｒｏｎ法完全适用于颗粒物悬浮体系中的形态分布表征     

Stadtökologie

Within the cities, natural environmental conditions become manifold modified. Thereby, together with the high density of population, enduring effects upon human feeling results. In order to ensure reasonable conditions of life, in spite of the many effective factors in the cities, enforced interdisciplinary research and teaching will be necessary.     

Abundance patterns and foraging activity of ant communities in abandoned,organic and commercial apple orchards in Northern California

The abundance patterns of ant communities were monitored with pitfall traps during 14 weeks in four northern California, dry farmed, apple orchards: an abandoned orchard undisturbed for 25 years, two ‘organically’ managed orchards, one with a cover crop of bell beans (Vicia faba) and grasses and the other kept clean of cover by discing, and a ‘commercial’ clean cultivated orchard sprayed with organophosphate insecticides. Six species of ants coexisted in the abandoned orchard, whereas only two species were found in the managed orchards. In both the organic and sprayed, clean cultivated systems, ants were more abundant in the orchard edges than in the vegetation-free centers. This trend was not apparent in the abandoned or organic cover orchards, where plant diversity in the center was similar to that of the edges. Ant predation on potato tuberworm larvae, Phthorimaea operculella, artificially placed on the orchard floor, declined with the intensity of management and vegetational simplication. A higher incidence of larval removal occurred in the edges than in the centers of the clean cultivated orchards. No noticeable populations of ants were detected on the trees in any of the orchards. Increased vegetational diversity and lack of disturbance appeared to affect ant locomotory activity and foraging efficiency by creating preferred sheltering and feeding sites.