网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
单选题
The suction - force principle of operation is a typical characteristic of （）.
A
centrifugal pumps
B
jet pumps
C
propeller pumps
D
reciprocating pumps
参考答案
参考解析
解析：
暂无解析
更多 “单选题The suction - force principle of operation is a typical characteristic of （）.A centrifugal pumpsB jet pumpsC propeller pumpsD reciprocating pumps” 相关考题
考题
If the suction pressure at the refrigeration compressor is below normal, the cause can beA.refrigerant overchargeB.overfeeding by the expansion valveC.a restricted suction strainerD.due to short cycling of the compress
考题
Which two valid declarations of a char？ （）A、 Char ch = “a”；B、 Char ch = ‘“‘ ‘；C、 Char ch = ‘cafe‘；D、 Char ch = “cafe”；E、 Char ch = ‘“ucafe‘；F、 Char ch = ‘“u10100‘；G、 Char ch = （char） true；
考题
选择适当的用语补充对话。（） ——What did you feel during the massage？ ——I am feel comfortable____________.A、The force is too heavyB、The force is too bigC、The force is too lightD、The force is too suitable
考题
A network administrator needs to force a high-performance switch that is located in the MDF to become the root bridge for a redundant path switched network. What can be done to ensure that this switch assumes the role as root bridge（）。A、Establish a direct link from the switch to all other switches in the network.B、Assign the switch a higher MAC address than the other switches in the network have.C、Configure the switch so that it has a lower priority than other switches in the network.D、Configure the switch for full-duplex operation and configure the other switches for half-duplex operation.E、Connect the switch directly to the MDF router, which will force the switch to assume the role of root bridge.
考题
单选题Which of the following statements is correct with regards to the operation of a centrifugal cargo pump?（）A
Oil is discharged from the impeller through the outletB
Gravity causes the oil to flow toward the dischargeC
The self-priming feature of the centrifugal pump enables it to draw its own suction as it startsD
The discharge capacity varies directly with the speed of the impeller
考题
单选题Which expression has the different meaning from entry into force ? “entry into force” means is（）.A
coming into effectB
moving to full effectC
being based on forceD
coming into force
考题
单选题Which of the listed operations will cause an automatically controlled refrigeration compressor to restart?（）A
Closing of the solenoid valveB
Closing of the expansion valveC
An increase in the suction pressureD
Decreasing the suction pressure
考题
单选题The static suction lift of a pump is the difference in elevation between the （）.A
centerline of the pump and the level of the liquid in the suction well when the source of liquid is below the pumpB
centerline of the pump and the suction liquid level when the source of liquid is above the pumpC
centerline of the pump and the level of the discharge liquidD
liquid levels of the suction and discharge
考题
单选题A pump is said to have "negative suction head" when the pump is located （）.A
between the suction and dischargeB
below the liquid supplyC
above the liquid supplyD
any of the above
考题
单选题What does the term head mean when applied to a fire pump?（）A
Length of the discharge pipeB
Height of the discharge pipeC
Difference between the discharge and suction pressuresD
Sum of discharge and suction pressures
考题
单选题If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.A
refrigerant overchargeB
overfeeding by the expansion valveC
a restricted suction strainerD
due to short cycling of the compressor
考题
单选题When students learn apple, orange, the teacher gives students another word fruit.Which principle does the teacher follow in his/her vocabulary teaching?A
Word-choice principle.B
Presentation principle.C
Culture principle.D
Systematic principle.
考题
单选题When students learn apple, orange, the teacher gives students another word fruit. Which principle does the teacher follow in his/her vocabulary teaching?A
Word-choice principle,B
Presentation principle.C
Culture principle.D
Systematic principle.
考题
单选题The static suction head of is the （）A
distance of the suction liquid level above the line of the pumpB
distance the suction liquid level is below the center line of the pumpC
force necessary to overcome frictional losses in the pump and pipingD
amount in inches of mercury the total suction head is below atmospheric pressure
考题
单选题What is the basic principle of the magnetic compass（）.A
Magnetic materials of the same polarity repel each other and those of opposite polarity attractB
The Earth's magnetic lines of force are parallel to the surface of the EarthC
Magnetic meridians connect points of equal magnetic variationD
The compass needle（s）will，when properly compensated，lie parallel to the isogonic lines of the Earth
考题
单选题An increase in the heat load to a refrigeration system will cause （）.A
the suction pressure to decreaseB
the suction temperature to increaseC
increased ice formation on the evaporator coilD
excessive short cycling of the compressor
考题
多选题Examine the commands executed to monitor database operations: $ conn sys oracle/oracle@prod as sysdba SQL VAR eid NUMBER SQL EXEC: eid := DBMS_SQL_MONITOR.BEGIN_OPERATION (‘batch_job’ , FORCED_TRACKING = ‘Y’); Which two statements are true?（）ADatabase operations will be monitored only when they consume a significant amount of resource.BDatabase operations for all sessions will be monitored.CDatabase operations will be monitored only if the STATISTICS_LEVEL parameter is set to TYPICAL and CONTROL_MANAGEMENT_PACK_ACCESS is set DIAGNISTIC + tuning.DOnly DML and DDL statements will be monitored for the session.EAll subsequent statements in the session will be treated as one database operation and will be monitored.
考题
单选题One of the differences between a two-stroke engine and a four-stroke engine is,（）A
a two-stroke engine works without exhaust operationB
a two-stroke engine works without compression strokeC
a two-stroke engine works without expansion strokeD
a two-stroke engine works without suction operation
考题
单选题The major difference between the discharge and suction valves installed in most low pressure, reciprocating air compressors is that（）A
one valve seats upwards, while the other seats downwardsB
the reed valves used on the discharge are made substantially thicker and heavier than the suction valvesC
the suction valve springs exert a greater tension than the discharge valve springsD
the discharge valve springs exert a greater tension than the suction valve springs
考题
单选题The purpose of the low pressure cut-out switch is to （）.A
maintain liquid refrigerant at the suction of the compressorB
maintain a preset suction pressure to the compressorC
start and stop the compressor at preset operating pressuresD
operate at minimum efficiency
考题
单选题选择适当的用语补充对话。（） ——What did you feel during the massage？ ——I am feel comfortable____________.A
The force is too heavyB
The force is too bigC
The force is too lightD
The force is too suitable
考题
单选题Which of the following problems would be the probable cause for the faulty operation of a reciprocating air compressor suction valve?（）A
Carbon build up in the piston ring beltB
Faulty operation of a cylinder un-loaderC
Compressor operation in an area of high relative humidityD
Lifting of intercooler rebel valve
考题
单选题A simple pumping system consists of a suction branch, a pump and （）.A
a priming deviceB
a discharge branchC
a filterD
a suction valve
考题
单选题在下列程序语句中，为任务间添加依赖关系的是（）。A
[operation1 addDependency：operation2]；B
[operation addExecutionBlock：^{}]；C
[operation waitUntilFinished]；D
[operation cancel]；
热门标签
最新试卷
