STEAM研究的患者为（）A、轻度哮喘患者B、重度哮喘患者C、轻中度哮喘患者D、中重度哮喘患者
STEAM研究的患者为（）
- A、轻度哮喘患者
- B、重度哮喘患者
- C、轻中度哮喘患者
- D、中重度哮喘患者
相关考题：
If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause may be ______.A.high steam pressure in the boilerB.abnormally high feed-water temperatureC.abnormally high boiler water temperatureD.steam demand exceeding feed pump capacity
Geothermal(地热)Energy 1 Since heat naturally moves from hotter regions to cooler ones, the heat from the earth's center flows outwards towards the surface. In this way, it transfers to the next layer of rock. If the temperature is high enough, some of this rock melts and forms magma(岩浆). The magma ascends in its turn towards the earth's surface. It often remains well below the earth's surface, creating vast areas of hot rock. In such regions, there are deep cracks, which allow rainwater to descend underground. Some of the heated rainwater travels back up to the earth's surface where it will appear as a hot spring. However, if this ascending hot water reaches a layer of impermeable(不可渗透的)rock, it remains trapped, forming a geothermal reservoir. If geothermal reservoirs are close enough to the surface, they can be reached by drilling wells. Hot water and steam shoot up the wells naturally, and can be used to produce electricity in geothermal power plants. 2.A few geothermal power plants depend on dry-stem reservoirs which produce steam but little or no water. In these cases, the steam is piped up directly to provide the power to spin a turbine generator. The first geothermal power plant, constructed at Lardarello in Italy, was of this type, and is still producing electricity today. 3.Most currently operating geothermal power plants are either "flash" steam plants or binary(双重的)plants. Flash plants produce mainly hot water ranging in temperature from 300° to 700°Fahrenheit. This water is passed through one or two separators where released from the pressure of the underground reservoir, it "flashes" or boils into steam Again, the force of this steam provides the energy to spin the turbine and produce electricity. The geothermal water and steam are then reinjected directly back down into the earth to maintain the volume and pressure of the reservoir. Gradually they will be reheated and can then be used again. 4.A reservoir with temperatures below 300° Fahrenheit is not hot enough to flash steam but it can still be used to generate electricity in binary fluid. The steam from this is used to power the turbines. As in the flash steam plant, the geothermal water is recycled back into the reservoir.文章(23~30)Paragraph1_____A.Dry steam plantsB.Binary plantsC.Origin of geothermal energyD.Generation of electricityE.Flash steam plantsF.Recyclable water and steam
Paragraph4_____A.Dry steam plantsB.Binary plantsC.Origin of geothermal energyD.Generation of electricityE.Flash steam plantsF.Recyclable water and steam
单选题Before starting a reciprocating, steam-driven pump that has been idle for a period of time, you should （）.Aopen the steam line mot valveBdrain the steam cylinderCclose the steam cylinder drainsDopen the liquid cylinder drains
单选题The steam boiler is part of a closed loop steam, whereby, after the energy of the steam is used up and it becomes water again, （） is collected and returned back to the boiler for heating up again to steam.Athe formerBthe firstCthe latterDthe last
单选题What is NOT a function of the steam drum of a marine water-tube boiler（）.AReceives saturated steam from the generating tubesBServes as a reservoir of boiler feed waterCHolds internal fittings for separation of moisture from steamDCollects steam exhausted from the turbines
单选题The（） is a smaller valve fitted in the auxiliary steam supply line, and is usually of the non-return type.Amain stem stop valveBauxiliary steam stop valveCfeed check or control valveDblow down valve
单选题Thermostatic steam pressure reducing valves are used in the fuel oil service system to control the（）Adouble bottom fuel oil tank temperatureBheater supply steam flowCpressure of the fuel supplied to the burnersDattemperator steam flow in the heater discharge circuit
单选题The boiler feed pump discharge pressure is higher than the steam drum pressure to （）.Aensure feed water flow into the boilerBkeep the steam drum pressure highCprevent water hammer in the feed lineDhelp the feed water flash to steam
单选题The water level in a steaming auxiliary boiler will always （）Arise when the steam pressure is increasedBremain constant as long as the feed pump operatesCfall when the steam pressure is decreasedDvary as the steam demand changes
单选题（）, iea steam cooler, may be filled in the boiler system to control the superheated steam temperature.AAn economizerBAn attemperatorCA water dramDA down-comer tube
单选题Foaming in the steam drum may be caused by （） in a boiler.Aoxygen in the waterBpoor boiler designCdensity too highDexcessive steam demand
单选题When steam is being raised on a boiler, the water level will normally （）.Adrop as the boiler warms upBrise as the boiler warms upCremain unchanged until the boiler is hot enoughDrise and fall with the steam demand
单选题Which of the listed types steam traps operates on the principle that hot water flashes to steam when its vapor pressure is rapidly reduced?（）ABall floatBThermostaticCBimetallicDImpulse
单选题Prior to lighting off a cold automatically fired auxiliary boiler, you should （）.Acheck and regulate the water levelBclose the air cock once fires are litCblowdown the gage glassDcrack the steam stop to assure protective steam flow
单选题The engine gives_______smoke and steam.AupBinCawayDoff