Which of the following problems will occur if the internal drain at either end of a hydraulic, two-way, spool-type directional control valve cylinder were to become plugged?（）
A、The reservoir would become vapor bound
B、The valve would be placed in hydraulic lock
C、The spring loaded relief ports would open
D、The buffering chambers would be unable to function
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In a centrifugal Freon refrigeration system, the overall capacity of the system is increased by（）
A、opening more bypass lines
B、opening additional expansion valves
C、adding refrigerant
D、speeding up the machine
The demisters installed in a flash-type evaporator serve to （）
A、deaerate the first effect distillate
B、filter the condensed flash vapors
C、deaerate the first and second effect distillate
D、remove small water droplets entrained in the flashed vapor
The part of the shipboard electrical system used to control the distribution of power to the branch circuits, is the （）.
A、bridge control panel
B、disconnect links
C、governor relay box
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Low compression pressure in a diesel engine can be caused by（）
A、improperly seating intake valves
B、leaking cylinder liner seal rings
C、late fuel injection timing
D、carbon deposits on the piston
The cylinder oil will have to neutralize the acidic products of combustion and have good （） properties to keep the metal surfaces clean.
A、detergent
B、de-oiling
C、defrosting
D、demulsifying
