正确答案: B

18周岁

题目：我国《海船船员发证规则》规定，申请值班水手和值班机工适任证书者，年龄不小于( )

解析：B

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学习资料的答案和解析：

[单选题]Diesel engine blow-by is the leakage of combustion gases past the( ).

compression and scraper rings

解析：解析：scraper：刮刀;groove：槽

[单选题]如果双速液压马达在重载时使用轻载挡可能导致( )。

安全阀开启

[单选题]第一组Older loop scavenged engines may have a single injector mounted centrally in the cylinder head. Because the exhaust valve is in the center of the cylinder head on modern uniflow scavenged engines the fuel valves (2 or 3) are arranged around the periphery of the head. The pressure at which the injector operates can be adjusted by adjusting the loading on the spring. The pressures at which the injectors operate vary depending on the engine, but can be as high as 540 bar. Some injectors have internal cooling passages in them extending into the nozzle through which cooling water is circulated. This is to prevent overheating and burning of the nozzle tip. Injectors on modern engines do not have internal cooling passages. They are cooled by a combination of the intensive bore cooling in the cylinder head being close to the valve pockets and by the fuel which is re-circulated through the injector when the follower is on the base of the cam or when the engine is stopped. As well as cooling the injector, re-circulating the fuel when the engine is stopped keeps the fuel at the correct viscosity for injection by preventing it from cooling down. Fuel injectors must be kept in good condition to maintain optimum efficiency, and to prevent conditions arising which could lead to damage within the cylinder. Injectors should be changed in line with manufacturers&39; recommendations, overhauled and tested. Springs can weaken with repeated operation leading to the injector opening at a lower pressure than designed. The needle valve and seat can wear which together with worn nozzle holes will lead to incorrect atomization and dribbling.

several injectors mounted around the external boundary of the cylinder head

[单选题]缝合伤口皮肤时针距为______。

1～1.5厘米

[单选题]下列不属于船舶消防设备的是：

各种泵。