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单选题
In a refrigeration system, which of the following statements describes the actions occurring when a solenoid valves, used in conjunction with an unloader head is energized?（）
A
The solenoid valves directs high pressure gas to the valve lifting device raising the suction valve off its seat and causing one specific cylinder to become unloaded
B
The solenoid valves directs high pressure gas to the underside of the unloading piston, causing it to rise and allowing the recirculating ports to be opened
C
When the solenoid valve becomes energized, the valve ports become closed, allowing discharge pressure to build up above the piston, shifting it and causing it to unload
D
The solenoid valve allows the refrigerant to pass from the suction chamber to the top of the unloader piston, causing the piston to lift and unload the cylinder
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更多 “单选题In a refrigeration system, which of the following statements describes the actions occurring when a solenoid valves, used in conjunction with an unloader head is energized?（）A The solenoid valves directs high pressure gas to the valve lifting device raising the suction valve off its seat and causing one specific cylinder to become unloadedB The solenoid valves directs high pressure gas to the underside of the unloading piston, causing it to rise and allowing the recirculating ports to be openedC When the solenoid valve becomes energized, the valve ports become closed, allowing discharge pressure to build up above the piston, shifting it and causing it to unloadD The solenoid valve allows the refrigerant to pass from the suction chamber to the top of the unloader piston, causing the piston to lift and unload the cylinder” 相关考题
考题
●Which of the following statements describe(s)the properties of a purely segmented memory system? (73) ．Ⅰ．It suffers from internal fragmentationⅡ．It permits implementation of virtual memoryⅢ．It divides memory into units of equal size(73) A．Ⅰ onlyB．Ⅲ onlyC．Ⅱ onlyD．Ⅰ andⅢ
考题
Which of the following statements describe(s) the properties of a purely segmented memory system?Ⅰ．It divides memory into units of equal sizeⅡ．It permits implementation of virtual memoryⅢ．It suffers from internal fragmentationA．Ⅰ onlyB．Ⅱ onlyC．Ⅲ onlyD．Ⅰand Ⅲ
考题
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?A.A shortage of liquid refrigerant.B.Excessive frost on the evaporator.C.Excessive condenser cooling water.D.Insufficient condenser cooling water flow.
考题
Which of the following statements best describes the relationship between a logical volume and a journaled file system (JFS)?()
A.Increasing the size of a logical volume also increases the size of the file systemB.Reducing the size of a logical volume requires reducing the size of the file system firstC.Increasing the size of a file system requires increasing the size of the logical volume firstD.Increasing the size of a file system also increases the size of the logical volume when necessary
考题
Which of the following statements is TRUE about mounting a file system?()
A.A file system cannot be mounted on a directory containing data.B.Mounting a file system on a mount point containing data will delete the data.C.Mounting a file system on a amount point containing data will make the data temporarily inaccessible.D.A systems administrator must manually create an empty directory prior to mounting an AIX JFS.
考题
Which of the following statements describe(s)the properties of a purely segmented memory system?(73).Ⅰ. It suffers from internal fragmentationⅡ. It permits implementation of virtual memoryⅢ. It divides memory into units of equal sizeA．Ⅰ onlyB．Ⅲ onlyC．Ⅱ onlyD．Ⅰand Ⅲ
考题
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B.Language is symbol
C.Animals also have language
D.Language is arbitrary
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Which of the following statements is NOT considered a characteristic of farming in the late 18th and early 19th centuries?（）A、Use of artificial fertilizer.B、Introduction of new agricultural machinery.C、The'Open-field'system.D、A system of crop rotation.
考题
Which of the following statements is NOT true?（）A、The open field system provided a good opportunity to experiment.B、The open field system wasted land.C、The open field system was wasteful of labor and time.D、The open field system made livestock farming difficult.
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考题
单选题Which of the following statements is NOT true?（）A
The open field system provided a good opportunity to experiment.B
The open field system wasted land.C
The open field system was wasteful of labor and time.D
The open field system made livestock farming difficult.
考题
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ALTER DATABASE B
ALTER SYSTEM C
ALTER USER D
ALTER REDO LOG
考题
单选题Which of the following statements is NOT considered a characteristic of farming in the late 18th and early 19th centuries?（）A
Use of artificial fertilizer.B
Introduction of new agricultural machinery.C
The'Open-field'system.D
A system of crop rotation.
考题
单选题Which of the following statements concerning butterfly valves is correct?（）A
Special tools are required for lapping or grindingB
It is impossible to throttle flow with a butterfly valveC
To close the valve, it is only necessary to turn the handle a quarter of a turnD
The butterfly valve should never be used in a freshwater system
考题
单选题Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）A
A shortage of liquid refrigerantB
Excessive frost on the evaporatorC
Excessive condenser cooling waterD
Insufficient condenser cooling water flow
考题
多选题You enabled an audit policy by issuing the following statements: SQL AUDIT POLICY ORA_DATABASE_PARAMETER BY SCOTT; SQL AUDIT POLICY ORA_DATABASE_PARAMETER BY SYS, SYSTEM; For which database users and for which executions is the audit policy now active? （）ASYS, SYSTEMBSCOTTCOnly for successful executionsDOnly for failed executionsEBoth successful and failed executions
考题
单选题In which of the listed refrigeration system components does superheating of the refrigerant take place?（）A
Expansion valveB
EvaporatorC
DrierD
Receiver
考题
单选题Which of the following statements is correct concerning a typical shipboard multi-coil refrigeration system?（）A
The liquid receiver functions to collect and remove non-condensable gasesB
A thermostatic expansion valve is used to control refrigerated space temperatureC
Refrigerant temperature in an evaporator is directly related to refrigerant pressureD
Dehydrators must be used continuously in a refrigeration system
考题
单选题Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions?（）A
Sub-cooled liquidB
Sub-cooled vaporC
Superheated vaporD
Liquid
考题
单选题Which of the listed statements is correct concerning refrigeration systems?（）A
Dehydrators must be used continuously in a refrigeration systemB
A 25 ton refrigeration system has the same cooling effect as melting 25 tons of ice in 24 hoursC
A thermostatic expansion valve is used to control refrigerated space temperatureD
The liquid receiver functions to collect and remove non- condensable gases
考题
单选题Which of the following statements is true about L3 cache?（）A
L3 cache operates faster than the system processorB
L3 cache runs at the speed of the processor.C
L3 cache can deliver data in as little as 15ns.D
L3 cache runs at the speed of the system bus.
考题
单选题Which of the following statements describes the functions of a reservoir used in a hydraulic system?（）A
Dissipate heatB
Trap foreign matterC
Separate air from the oilD
All of the above
考题
单选题Which of the listed refrigeration system components keeps the refrigerant circulating through the system?（）A
Expansion valveB
CondenserC
EvaporatorD
Compressor
考题
单选题Which of the following statements best describes the relationship between a logical volume and a journaled file system (JFS)?（）A
Increasing the size of a logical volume also increases the size of the file systemB
Reducing the size of a logical volume requires reducing the size of the file system firstC
Increasing the size of a file system requires increasing the size of the logical volume firstD
Increasing the size of a file system also increases the size of the logical volume when necessary
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