【名词&注释】
不平衡(unbalance)、离心泵理论(centrifugal pump theory)、人工呼吸(artificial respiration)、在海上
[判断题]对溺水者在做人工呼吸之前，应清理口鼻内的异物，包括假牙。
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举一反三：
[单选题]Lubrication for the main reduction gears used with diesel engines is usually supplied by
A. oil from the main engine sump
B. an independent lube oil system
C. the stern bearing head tank
D. the stem bearing sump tank
[单选题]Diesel engines driving alternators operating in parallel must maintain a set frequency regardless of load changes. The governor characteristic used to accomplish this is known as _______.
A. actuation
B. sensitivity
C. compensation
D. promptness
[单选题]第一组： The Wartsila 50DF operates on the lean-bum principle: the mixture of air and gas in the cylinder has more air than is needed for complete combustion. Lean combustion reduces peak temperatures and therefore NOx emissions. Efficiency is increased and higher output is reached while avoiding knocking. Combustion of the lean air-fuel mixture is initiated by injecting a small amount of LFO (pilot fuel) into the cylinder. The pilot fuel is ignited in a conventional diesel process, providing a high-energy ignition source for the main engine. To obtain the best efficiency and lowest emissions, every cylinder is individually controlled to ensure operation at the correct air-fuel ratio and with the correct amount and timing of pilot fuel rejection. Wartsila has developed a special electronic control system to cope with the demanding task of controlling the combustion in each cylinder, and to ensure optimal performance in terms of efficiency and emissions under all conditions by keeping each cylinder within the operating window. Stable and well-controlled combustion also contributes to less mechanical and thermal load on the engine components. Current stringent emission regulations demand the reduction of NOx emissions. In an internal combustion engine this means controlling peak temperature and residence time, which are the main parameters governing NOx formations. In the Wartsila 50DF engine, the air-fuel ratio is very high (typically 2.2). Since the same specific heat quantity released by combustion is used to heat up a larger mass of air, the maximum temperature and consequently NOx formation are lower. The mixture is uniform. throughout the cylinder since the fuel and air are premixed before introduction into the cylinders, which helps to avoid local NOx formation points within the cylinder. Benefiting from this unique feature, NOx emissions from the Wartsila 50DF are extremely and comply with the most stringent existing legislation.What is the combustion feature of the Wartsila 50DF?
A. Lean air in the cylinder
B. Excessive fuel in the cylinder
C. Excessive air in the cylinder
D. Spark ignition
[单选题]《国际海上避碰规则》规定，为避免与他船碰撞而采取的行动应能________。
A. 导致紧迫局面的消失
B. 导致让清他船
C. 导致在安全距离上驶过
D. 避免碰撞
[单选题]We always have a lot of things ________during the voyage.
A. do
B. doing
C. to do
D. does
[单选题]一级啮合传动且转向一致的是( )传动。
A. 圆锥齿轮
B. 内啮合齿轮
C. 外啮合齿轮
D. 蜗轮蜗杆
[单选题]在海上,用雷达来协助避碰时,通常把雷达放在________海里档进行标绘。
在海上，用雷达来协助避碰时，通常把雷达放在________海里档进行标绘。
A. 12B． 6C． 3
B. １２
C. ６
D. ３
[单选题]( )工况，离心泵理论上会产生不平衡液压径向力。
A. 导轮泵在设计
B. 导轮泵在非设计
C. 蜗壳泵在设计
D. 蜗壳泵在非设计
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