魔棒发光原理是利用H2O2氧化草酸二酯(CPPO)产生能量,该能量被传递给荧光物

题型:选择题

问题:

魔棒发光原理是利用H2O2氧化草酸二酯(CPPO)产生能量,该能量被传递给荧光物质后发出荧光.草酸二酯结构简式如图所示,下列有关草酸二酯的说法正确的是(  )

A.草酸二酯属于芳香烃

B.草酸二酯的分子式为C26H23O8Cl6

C.草酸二酯难溶于水

D.1mol草酸二酯最多可与4mol NaOH反应

考点:有机物的官能团有机物按官能团的分类
题型:选择题

People are indulging in an illusion whenever they find themselves explaining at a cocktail (鸡尾酒) party, say, that they are "in computers," or "in telecommunications," or "in electronic funds transfer". The implication is that they are part of the high-tech world. Just between US, they usually aren’t. The researchers who made fundamental breakthroughs in those areas are in a high-tech business. The rest of us are (8) of their work. We use computers and other new technology components to develop our products or to organize our affairs. Because we go about this work in teams and projects and other tightly knit working groups(紧密联系在一起的工作小组), we are mostly in the human communication business. Our successes stem from good human interactions by all participants in the effort, and our failures stem from poor human interactions.
The main reason we tend to focus on the (9) rather than the human side of the work is not because it’s more (10) , but because it’s easier to do. Getting the new disk drive installed is positively trivial compared to figuring out why Horace is in a blue funk (恐惧) or why Susan is dissatisfied with the company after only a few months. Human interactions are complicated and never very crisp (干脆的, 干净利落的) and clean in their effects, but they matter more than any other aspect of the work.
If you find yourself concentrating on the (11) rather than the (12) , you’re like the vaudeville character (杂耍人物) who loses his keys on a dark street and looks for them on the adjacent street because, as he explains, "The light is better there!".

A.technology
B.sociology
C.physiology
D.astronomy

题型:选择题

如果-5m表示一个物体向南运动5m,那么+3m表示______,物体原地不动记为______.

题型:选择题

We ___________ a good time. [ ]

A. has

B. had

题型:选择题

《铁路线路设计规范》规定,(),需用竖曲线连接。

A.Ⅰ、Ⅱ级铁路相邻坡段坡度的代数差大于3‰和Ⅲ级铁路相邻坡段坡度的代数差大于4‰时

B.Ⅰ、Ⅱ级铁路相邻坡段坡度的代数差小于3‰和Ⅲ级铁路相邻坡段坡度的代数差小于4‰时

C.Ⅰ、Ⅱ级铁路相邻坡段坡度的代数差大于2‰和Ⅲ级铁路相邻坡段坡度的代数差大于3‰时

D.Ⅰ、Ⅱ级铁路相邻坡段坡度的代数差大于1‰和Ⅲ级铁路相邻坡段坡度的代数差大于2‰时

题型:选择题

品目7015的其他未经光学加工玻璃

更多题库