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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
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更多 “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
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
考题
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 plants
B.Binary plants
C.Origin of geothermal energy
D.Generation of electricity
E.Flash steam plants
F.Recyclable water and steam
考题
Paragraph4_____A.Dry steam plants
B.Binary plants
C.Origin of geothermal energy
D.Generation of electricity
E.Flash steam plants
F.Recyclable water and steam
考题
单选题Before starting a reciprocating, steam-driven pump that has been idle for a period of time, you should （）.A
open the steam line mot valveB
drain the steam cylinderC
close the steam cylinder drainsD
open the liquid cylinder drains
考题
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.A
the formerB
the firstC
the latterD
the last
考题
单选题What is NOT a function of the steam drum of a marine water-tube boiler（）.A
Receives saturated steam from the generating tubesB
Serves as a reservoir of boiler feed waterC
Holds internal fittings for separation of moisture from steamD
Collects steam exhausted from the turbines
考题
单选题The（） is a smaller valve fitted in the auxiliary steam supply line, and is usually of the non-return type.A
main stem stop valveB
auxiliary steam stop valveC
feed check or control valveD
blow down valve
考题
单选题Thermostatic steam pressure reducing valves are used in the fuel oil service system to control the（）A
double bottom fuel oil tank temperatureB
heater supply steam flowC
pressure of the fuel supplied to the burnersD
attemperator steam flow in the heater discharge circuit
考题
单选题The boiler feed pump discharge pressure is higher than the steam drum pressure to （）.A
ensure feed water flow into the boilerB
keep the steam drum pressure highC
prevent water hammer in the feed lineD
help the feed water flash to steam
考题
单选题The water level in a steaming auxiliary boiler will always （）A
rise when the steam pressure is increasedB
remain constant as long as the feed pump operatesC
fall when the steam pressure is decreasedD
vary as the steam demand changes
考题
单选题（）, iea steam cooler, may be filled in the boiler system to control the superheated steam temperature.A
An economizerB
An attemperatorC
A water dramD
A down-comer tube
考题
单选题Foaming in the steam drum may be caused by （） in a boiler.A
oxygen in the waterB
poor boiler designC
density too highD
excessive steam demand
考题
单选题When steam is being raised on a boiler, the water level will normally （）.A
drop as the boiler warms upB
rise as the boiler warms upC
remain unchanged until the boiler is hot enoughD
rise and fall with the steam demand
考题
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?（）A
Ball floatB
ThermostaticC
BimetallicD
Impulse
考题
单选题Prior to lighting off a cold automatically fired auxiliary boiler, you should （）.A
check and regulate the water levelB
close the air cock once fires are litC
blowdown the gage glassD
crack the steam stop to assure protective steam flow
考题
单选题The engine gives_______smoke and steam.A
upB
inC
awayD
off
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