【简答题】金晶体的最小重复单元(也称晶胞)是面心立方体,如下图所示,即在立方体的8个顶点各有一个金原子,各个面的中心有一个金原子,每个金原子被相邻的晶胞所共有。金原子的直径为d,用N A 表示阿伏加德罗常数,M表示金的摩尔质量。 (1)金晶体的每个晶胞中含有_______个金原子。 (2)欲计算一个晶胞的体积,除假定金原子是刚性小球外,还应假定__________________。 (3)一个晶胞的体积是_...
【单选题】There was a _________ in her throat as she gazed at the child who had been separated from her for five years
【简答题】A.Because she had too many things with her. B.Because she was sick. C.Because she was quite lazy. D.Because she didn't want to get sick at high altitudes.
【单选题】目前纯电动车所采用的安全防护级别一般为( )
【单选题】Smuggling It is not unusual for a pet to be sent by air cargo from Columbia to New York, but last December's shipment of a 4-year-old sheep dog caught a New York Kennedy Airport Customs inspector's ey...
A.
it could stand only on its hind legs.
C.
it was very attractive.
D.
it had a very big abdomen.
【判断题】只有将对幼儿的保育和教育紧密地、有机地联系在一起,相互兼顾、相互渗透、相互促进,才能最大限度地促进幼儿身心和谐、健康的发展。
【单选题】该患者确诊为中央型肺癌,行在全肺叶切除术加淋巴结切除术,最不可能发生的并发症是