单选题The operating medium for control systems may be （）.Acompressed airBhydraulic oilCelectricityDAll of the above
单选题
The operating medium for control systems may be （）.
A
compressed air
B
hydraulic oil
C
electricity
D
All of the above
参考解析
解析：
暂无解析
相关考题：
Cost management includes processes that are required to maintain financial control of projects. These processes may include:A . economic evaluationB . cost estimatingC . cost forecastingD . B and CE . All of the above.
Quality control is normally performed by the _____ .A . QA personnelB . project teamC . operating personnelD . project managementE . None of the above.
127 Cost management includes processes that are required to maintain financial control of projects. These processes may include:A. economic evaluationB. cost estimatingC. cost forecastingD. B and CE. All of the above
Most operating systems have a standard set of （） to handle the processing of all input and output instructions.A.spreadsheetB.control instructionsC.I/O operationD.data table
Which of the following can be used in hydraulic transmission system?A.Hydraulic oilB.Animal oilC.Light oilD.Fuel oil
Which statement is TRUE concerning the placard entitled Discharge of Oil Prohibited ________．A.It is required on all vesselsB.It may be located in a conspicuous place in the wheelhouseC.It may be located at the bilge and ballast pump control stationD.All of the above
When steering on autopilot which of the following input conditions may NOT have an effect on the control of the steering gear ________．A.Non-follow-upB.Rudder adjustmentC.Weather adjustmentD.All the above may be activated
Most operating systems have a standard set of （ ） to handle the processing of all input and output instructions.A.SPREADSHEET B.CONTROL INSTRUCTIONS C.I/O OPERATION D.DATA TABLE
In the fields of physical security and information security, access control is the selective restriction of access to a place or other resource. The act of accessing may mean consuming, entering, or using. Permission to access a resource is called authorization （授权）．An access control mechanism （71） between a user （or a process executing on behalf of a user） and system resources, such as applications, operating systems, firewalls, routers, files, and databases. The system must first authenticate（验证）a user seeking access. Typically the authentication function determines whether the user is （72） to access the system at all. Then the access control function determines if the specific requested access by this user is permitted. A security administrator maintains an authorization database that specifies what type of access to which resources is allowed for this user. The access control function consults this database to determine whether to（73）access. An auditing function monitors and keeps a record of user accesses to system resources.In practice, a number of（74）may cooperatively share the access control function. All operating systems have at least a rudimentary（基本的）, and in many cases a quite robust, access control component. Add-on security packages can add to the（75）access control capabilities of the OS. Particular applications or utilities, such as a database management system, also incorporate access control functions. External devices, such as firewalls, can also provide access control services.A.open B.monitor C.grant D.seek
Most operating systems have a standard set of ( ) to handle the processing of all input and output instructions. A.spreadsheet B.control instructions C. I/O operation D.datA.table
Most Computer operating systems in use today, including all consumer-targeted systems, include a TCP/IP（）.A、planB、requirementC、implementationD、design
单选题Strainers are commonly used in hydraulic systems to （）.Aprotect the pump from fine soluble contaminantsBprevent solid particles from entering the pumpCprevent solid particles from entering the filterDprotect the directional control valves
单选题In comparison to electric power，hydraulic power for jacking systems has the advantage of（）.Abetter control capabilitiesBless maintenance and repairCfewer personnel needed during jackingDless preload needed
单选题Which statement is TRUE concerning the placard entitled Discharge of Oil Prohibited（）.AIt is required on all vesselsBIt may be located in a conspicuous place in the wheelhouseCIt may be located at the bilge and ballast pump control stationDAll of the above
单选题It is important with all hydraulic systems to ensure that interlocking arrangements provided for pump or motor control levers are （） before the pump driving motor can be started.Ain the pert positionBin the starboard positionCin the neutral positionDto be dismantled
单选题For occasional heavy loads, two cranes can be arranged to work together. The operating （） for deck crane motors may be hydraulic electric.AprincipleBmediumCinstructionDvoltage
单选题The function of the hydraulic telemotor transmitter used in an electro-hydraulic steering gear system is to （）.Atransmit the rudder angle to the bridge indicatorBprevent the control linkage from striking the stops when hard overCautomatically purge all entrained air from the systemDsend hydraulic signals to the receiving unit
单选题Fire detecting systems on merchant vessels may be arranged to sense （）.AsmokeBrate of temperature riseCionized particlesDall of the above
单选题Air line lubricators are used in compressed air systems to lubricate （）.Athe suction and discharge valvesBtools and equipment served by compressed airCair line reducing valvesDall of the above
单选题External and internal leakage in hydraulic systems may be caused by （）.Aunusual vibrationBexcessive worn partsCabnormal pressureDany of the above
单选题Compressed air is used on board ship for all the following purposes except （）.Astarting diesel enginesBpneumatic control systemsCpneumatic toolsDsupercharging air
单选题Compressed air is used on board ship （）.Afor starting diesel enginesBin pneumatic control systemCin pneumatic toolsDAll the above are true
单选题Pressure in an operating hydraulic system is developed （）.Aonly by the pump as its primary functionBby resistance to the fluid flow through the systemCby the thermal input to the systems fluidDsolely by the charge applied by the accumulators
单选题A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.Athe four-way control valve failing to shiftBthe bleeder valve sticking in the open positionCcold hydraulic fluidDa clogged air vent falter on the oil reservoir
单选题The most common forms of main drive used on deck auxiliaries are （）.Asteam plants, electric motors and compressed airBdiesel engine, hydraulic machinery and compressed airCsteam plants, electric motors and hydraulic machineryDdiesel engines, steam plants and hydraulic machinery
单选题Most Computer operating systems in use today, including all consumer-targeted systems, include a TCP/IP（）.AplanBrequirementCimplementationDdesign
单选题Which of the listed pressure control valves would be used to establish the maximum operating pressure of a hydraulic system?（）APressure-reducing valveBUnloading valveCCounterbalance valveDPressure-relief valve