排序方式: 共有159条查询结果,搜索用时 939 毫秒
91.
pH在2~4的酸性介质中,采用分光光度法,用草酸掩蔽干扰金属离子,以偶氮氯膦-Ⅲ为显色剂,在680nm波长处测量吸光度.结果表明,稀土含量在0~55μg/mL之间时符合比尔定律,加标回收试验显示该法准确可靠. 相似文献
92.
93.
94.
Inductive energy storage systems (IES)require opening switches which are technically much more difficult to realize than closing switches. Institute of Advanced Technology ( IAT ) puts forward a meat grinder with an inductive pulse power topology called slow transfer of energy through capacitive hybrid (STRETCH). In this topology, an integrated gate-commutated thyristor (IGCT) is capable of breaking the charging currents on the order of 4 kA, and it may encounter difficulties in expanding to higher energy systems. German-French Institute of Saint Louis (ISL) has developed a high-power opening switch based on standard high-power thyristors by using their so-called inverse current commutation with semiconductor devices (ICCOS) countercurrent commutation principle. Two topologies of the STRETCH meat grinder with ICCOS are analyzed. And they are compared based on the voltage across the main switch, the current multiplication factor and other aspects by u- sing Matlab simulations. The advantages and disadvantages of the two topologies are shown through the comparisons. Therefore a more suitable topology can be chosen for realistic applications accord- ing to their performances. 相似文献
95.
稀土对电沉积Zn-Fe-La三元合金性能影响的研究 总被引:1,自引:0,他引:1
为了获得更加光亮、致密的Zn-Fe-La三元合金镀层,针对电沉积Zn-Fe-La三元合金镀液组成及工艺条件,系统地研究了稀土对镀层成分含量、镀液稳定性、镀液分散能力以及pH值的影响,测定了镀层的极化曲线、稳定电位和极化电阻,比较了不同稀土含量对镀层耐蚀性的影响.结果表明:稀土的加入可提高镀液稳定性、分散能力,增加电沉积过程阴极极化,使阳极钝化前的活性区腐蚀电位正移,自溶解速度下降,有利于提高镀层耐蚀性,其耐蚀性比Zn-Fe合金镀层及纯Zn镀层有很大提高. 相似文献
96.
97.
98.
99.
为研究海绵道路对降雨径流过程的非点源污染负荷削减效果,以武汉市青山区某工业道路为研究对象,设计3组低影响开发(LID)措施方案:下凹式绿地(方案I)、下凹式绿地与透水砖组合(方案II)、下凹式绿地与透水砖和透水路面组合(方案III).通过暴雨洪水管理模型对研究区的非点源污染负荷进行模拟研究,分析不同暴雨重现期下研究区降... 相似文献
100.