宽带IP城域网规划设计

本文针对当前宽带城域网的主流技术进行对照分析,设计出一个既能适应竞争形式需要、又能最大限度利用现有电信资源的宽带IP城域网,给出其整体设计原则和网络构架.     

Deregulation of a Ca2+/calmodulin-dependent kinase leads to spontaneous nodule development

Induced development of a new plant organ in response to rhizobia is the most prominent manifestation of legume root-nodule symbiosis with nitrogen-fixing bacteria. Here we show that the complex root-nodule organogenic programme can be genetically deregulated to trigger de novo nodule formation in the absence of rhizobia or exogenous rhizobial signals. In an ethylmethane sulphonate-induced snf1 (spontaneous nodule formation) mutant of Lotus japonicus, a single amino-acid replacement in a Ca2+/calmodulin-dependent protein kinase (CCaMK) is sufficient to turn fully differentiated root cortical cells into meristematic founder cells of root nodule primordia. These spontaneous nodules are genuine nodules with an ontogeny similar to that of rhizobial-induced root nodules, corroborating previous physiological studies. Using two receptor-deficient genetic backgrounds we provide evidence for a developmentally integrated spontaneous nodulation process that is independent of lipochitin-oligosaccharide signal perception and oscillations in Ca2+ second messenger levels. Our results reveal a key regulatory position of CCaMK upstream of all components required for cell-cycle activation, and a phenotypically divergent series of mutant alleles demonstrates positive and negative regulation of the process.     

一种丙烯酸聚合物锅炉水处理药剂性能研究

对一种锅炉水处理药剂的除垢、防垢性能、毒性能等进行了实验。实验得到了该药剂用于防垢时的锅炉原水硬度和用量关系式:y=0.095 1x+0.002 31以及除垢时的用量曲线。实验结果表明:该药剂使用温度广(100~223℃),可钝化锅炉金属,对锅炉蒸汽无污染,可用于食品、药品等对蒸汽品质有特殊要求的工业领域。