更多"（）is not contained in the NM Weekly"的相关试题:
[判断题]波长间隔：紫外区5nm，可见区10nm，近红外区50nm或40nm，远红外区0.5μm。
[单项选择]光纤通信系统存在着三个传输窗口，他们的传输光波波长分别为：850nm、1310nm和（）nm。
A. 1330
B. 1510
C. 1550
D. 1560
[多项选择]光纤通信系统存在着三个传输窗口，他们的传输光波波长分别为：（）nm、（）nm和（）nm。
A. 850
B. 1310
C. 1550
D. 1560
[判断题]分光光度法测定叶绿素a时，以纯水作空白吸光度测定，对样品在750nm、663nm、645nm和630nm波长下的吸光度进行校正。
[判断题]RGB单色光可以合成波长在380nm到780nm的单色光。
[判断题]蛋白质与核酸的紫外吸收最高峰值分别是260nm和280nm。
[单项选择]The self-contained breathing device should not be used in which situation?（）
A. Oxygen deficient spaces
B. Compartments containing poisonous vapors
C. Fighting fires that produce heavy smoke
D. Underwater search
[单项选择]After putting on a self-contained breathing apparatus，you open the air supply and hear a continuous ringing of a bell. What does this mean? （）
A. The unit is working properly
B. The face mask is not sealed properly
C. The air bottle needs to be refilled
D. The air supply hose has a leak
[单项选择]光通信的三个低损耗是1310nm、850nm和（）。
A. 1550nm
B. 1560nm
C. 1570nm
D. 1540nm
[单项选择]易位子直径约8.5nm，中心通道直径为（）nm。
A. 2
B. 4
C. 6
D. 8
[判断题]荧光磁粉检测时，黑光波长应在320nm～500nm的范围内。
[单项选择]从波分复用的技术观点出发，把1570nm-1604nm称为（）。
A. C波段
B. L波段
C. S波段
D. U波段
[单项选择]A ship must have a self-contained breathing apparatus to be used as protection from gas leaking from a refrigeration unit. To meet this requirement，you may use（）.
A. a gas mask certified by the Mine Safety and Health Administration
B. the same self-contained breathing apparatus required with the fireman's outfit
C. an oxygen breathing apparatus，provided that the device has been inspected within three years
D. a portable ventilation system that will provide a complete change of air every three minutes
[单项选择]The bypass valve on a self-contained breathing device should be opened if（）.
A. you are entering a space containing poisonous vapors
B. you are entering a space containing explosive gases
C. the regulator of the breathing apparatus malfunctions
D. the face piece of the breathing device is too tight
[单项选择]The rated operating time of a self-contained breathing device may be reduced in actual use because of（）.
A. pressure differences in the atmosphere
B. the length of the hose attached to the facepiece
C. the physical exertion of the person wearing the device
D. spaces containing poisonous vapors
[单项选择]The ratio of the weight of moisture contained in a given volume of air, to the weight of moisture that the same sample would hold if saturated, is called the（）.
A. absolute humidity
B. relative humidity
C. specific humidity
D. total humidity
