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W. Merbach 《Isotopes in environmental and health studies》2013,49(2-3):173-178
White lupins (Lupinus albus L., var. Kievsky mutant) were grown in Mitscherlich pots. 15NH4NO3 or NH4 15NO3 (10 or 95 at% 15N exc.) was applied at the late vegetative stage (14–16 leaves) or at the generative stage (end of bloom), respectively. Dry weight increase (ΔDW) of the plants as well as the 15N distribution in different organs and N fractions (NO3 ?-N, NH2-N, protein N) were investigated after 5 days and 50 days (maturity). The following results were obtained: 1. In comparison with the 15N derived from NO3 ?, the 15N derived from NH4 + was more strongly retained in the roots. When transported into the shoot, it was more strongly translocated into the tip. 2. More 15N derived from NH4 + was incorporated into proteins and reduced soluble N compounds than 15N derived from NO4 ?. Even in the above-ground plant tissues, a considerable proportion of the latter was found as NO3 ?. 3. In the long-term experiment (harvest at maturity 50 days after application), no difference in translocation and incorporation could be found between the two offered 15N sources. 相似文献
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为了减少润滑液对石油的依赖,发展环境友好水基润滑液,本文通过在蒸馏水中加入螺旋藻、白葡萄球菌、寡核苷酸和丝素四种水溶性微粒来改善水的摩擦学特性.采用原子力显微镜和扫描电子显微镜对螺旋藻、白葡萄球菌、寡核苷酸和丝素进行结构表征;采用微摩擦试验仪对蒸馏水和四种水基润滑液摩擦性能进行了评价,采用流变仪对其流变性进行了评价.结果表明:①螺旋藻结构为螺旋状,白葡萄球菌为球状,寡核苷酸和丝素为线状;②螺旋藻的减摩效果最好,白葡萄球菌次之,最后是寡核苷酸和丝素;随着载荷增大蒸馏水摩擦系数减小,四种水基润滑液摩擦系数均增大;随着滑动速度增大摩擦系数均减小;③蒸馏水中添加微粒后仍为牛顿流体,但黏度增大.通过对机理进行分析,认为螺旋藻减摩效果最好是由于表面的螺旋结构能够产生足够大的滑动摩擦力,容易克服滚动阻力偶使微粒滚动起来;载荷增大四种水基润滑液摩擦系数均增大是微粒滚动阻力偶增大造成的;滑动速度增大四种水基润滑液摩擦系数均减小是微粒聚集体逐渐被分解造成的. 相似文献
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鄱阳湖黄鳝体内鳗鲡独孤吸虫季节动态与种群分布 总被引:1,自引:1,他引:0
通过对鄱阳湖黄鳝体内鳗鲡独孤吸虫感染情况的调查,结果发现在799尾黄鳝中,有101尾黄鳝的消化道中发现有吸虫感染,感染率为12.64%,丰盛度为3.33±1.71。不同月份之间黄鳝体内鳗鲡孤独吸虫的感染率存在显著的差异(G=144.968>x02.005=18.548,df=6,P<0.005);其中5月份的感染率与丰 相似文献
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介绍了一种增加连接效率的PCR产物克隆技术,即SmaI内切酶参与的PCR产物与SmaI酶切的载体的连接;并通过克隆黄鳝基因组中一段约250bp的PCR产物的实例证实了该技术的可靠有效性. 相似文献