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铁与水蒸气反应的实验改进 被引量:13
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作者 赖陆锋 李春燕 《化学教育》 CAS 2008年第3期63-63,共1页
新人教版必修1中“铁与水蒸气反应”的实验,该实验装置虽简单易操作,但实验成功率很低,故笔者对该实验装置进行了小改进,设计了一种实验装置同样简单易操作,但实验现象更明显,实验成功率更高的实验装置。
关键词 湿沙子 铁粉 水蒸气
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Comparison of Germination Strategies of Artemisia ordosica with Its Two Congeners from Deserts of China and Israel 被引量:50
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作者 黄振英 Yitzchak GUTTERMAN 《Acta Botanica Sinica》 CSCD 2000年第1期71-80,共10页
Artemisia ordosica Krasch. is a dominant shrub occurring mainly on stable sand dunes in the Gobi Desert of China, in the Mongolian phytogeographic region. Achenes of A. ordosica germinate in light but poorly in ... Artemisia ordosica Krasch. is a dominant shrub occurring mainly on stable sand dunes in the Gobi Desert of China, in the Mongolian phytogeographic region. Achenes of A. ordosica germinate in light but poorly in dark and light is the limiting factor regulating the achene germination in sand depth. Achenes germinate in spring or autumn with an optimal temperature of 20 ℃. Achene mucilage can absorb large amounts of water and has important ecological function. Salt concentrations and sand moisture may regulate achene germination in sand. A. ordosica, A. sphaerocephala Krasch. and A. monosperma Delile. from different climates have similar responses to light, the underground location of achene, and sand moisture. Percentage of seedling emergence from different levels of sand depth is depends on the specific, temperature and intensity of light penetrating through the sand depths, as well as on sand moisture. The desert sand habitat seems to have had a dominant influence on the evolution of the germination strategies of these 3 Artemisia species. 展开更多
关键词 ARTEMISIA mucilaginous achenes sand temperatures light sand depth sand moisture germination strategies
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