The purpose of the flame in flame atomic-absorption spectroscopy is to（）

[单选题]Flame Detail指的是（）。A . 火焰的大小B . 火焰精细度C . 火焰的高度D . 火焰的样本数

[单选题]In the presence of an open flame or hot surfaces, chlorinated flourocarbon refrigerants decomposes and form .A．petroleum crystalsB．phosgene gasC．water vaporD．carbon monoxide

[单选题]If the flame from combustion in the cylinder of a four-stroke engine past the piston into the space below, the accumulation of flammable mixture would be ignited, thus resulting in _____.A．the crankcase explosionB．lifting of the cylinder safety valve

[单选题]If the flame from combustion in the cylinder of a four-stroke engine past the piston into the space below, the accumulation of flammable mixture would be ignited, thus resulting in （）.A . the crankcase explosionB . lifting of the cylinder safety valv

[单选题]When there is a flame failure in an automatically fired auxiliary boiler, the （）.A . air supply is shut offB . fuel supply is shut offC . water supply is shut offD . safety valve lift

[名词解释] atomic force microscope ；AFM（原子力显微镜）

[单选题]The purpose of the writing is to ______.A． promote scenic spots in Canada B. advertise for the sports in BanffC． introduce tourist activities in Banff D. describe breathtaking views in Banff

[单选题]The purpose of the memo is toA．attract students’interest in the programmeB．require the parents to select a sport for their chinldC．help the staff explain the programme to the parentsD．remind teachers and lifeguards to be present on time

[单选题]The purpose of the program is to provide training for employees so that they can work ______.A． lateB． laterC． latelyD． latest

[单选题]The purpose of the requirements definition phase is to produce a clear，complete，consistent，and testable (66) of the technical requirements for the software product．D．uring the requirements definition phase，the requirements definition team uses an ite