Gyrocompass repeaters reproduce the indications of the master gyrocompass. They are().
A. accurate only in the Polar regions
B. accurate electronic servomechanisms
C. hand operated
D. accurate only if the vessel is underway
对于下面所列举的几种气体,比空气重的气体有()
A. CH4
B. NH3
C. H2
D. C02
E. CO
F. N02
G. H2S
H. S02
供应商认为企业的业务量很低,但是此业务的吸引力很大,具有这种特征的是()
A. 维持象限
B. 盘剥象限
C. 发展象限
D. 核心象限
规范中规定,舱底水管应在船舶横倾()以内把舱底水排干。
A. 5º
B. 10º
C. 15º
D. 20º