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In the refrigeration compressor the temperature of the vapor is （） by compression.
A . raised
B . risen
C . reduced
D . maintained constant
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The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
A . Cross
B . Parallel
C . Counter
D . Circular
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The dew point of air is reached when the wet bulb temperature is （）.
A . Twice the dry bulb temperature
B . 10℃ above the dry bulb temperature
C . 5℃ above the dry bulb temperature
D . Equal to the dry bulb temperature
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A cargo hold has been determined to have a relative humidity of 80% and a dry bulb temperature of 80 ℃ and a dry bulb temperature of 85℃.When the hold is sealed and the dry bulb temperature decreases, the relative humidity in the space will （）
A . decrease
B . increase
C . decrease to zero
D . remain unchanged
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The temperature of the refrigerant in the evaporator coil depends mostly upon the （）.
A . refrigerant pressure in the evaporator
B . cooling water temperature to the condenser
C . heat load in the refrigerator compartment
D . solenoid valve in the liquid line
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As the temperature for a given mass of air increases，the（）.
A . dew point increases
B . dew point decreases
C . relative humidity increases
D . relative humidity decrease
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Increasing the temperature of a fuel will reduce its （）.
A . viscosity
B . pressure
C . resistance
D . setting point
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Which of the following relationships should occur between the temperature developed in a combustion space, and the compression ratio of the engine?（）
A . Higher compression ratios create higher temperature
B . Higher temperatures create higher compression ratios
C . low temperatures create higher compression ratios
D . Higher compression ratios create low temperature
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As the temperature of an air mass decreases，the（）.
A . absolute humidity decreases
B . relative humidity increases
C . specific humidity decreases
D . dew point rise
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The temperature of a refrigerant gas is the highest （）.
A . at the compressor discharge
B . at the compressor suction
C . in the expansion valve
D . in the receiver
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The temperature difference between the inlet and outlet temperature of the lube oil cooler in the lubricating system for the diesel engine is generally between （）.
A . 8-10℃
B . 10-12℃
C . 10-15℃
D . 10-20℃
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The temperature of the fuel oil received during bunkering operations is critical in determining the（）
A . expansion space to leave in a tank
B . flash point at which the fuel will burn
C . temperature to which the fuel must be heated
D . rate at which the fuel can be pumped during transfer operatio
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（） is used for sensing the temperature of the room in the air condition system.
A . An expansion valve
B . An evaporator
C . A thermostat
D . A condenser
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As the temperature for a given mass of air increase, the（）.
A . dew point increase
B . dew point decreases
C . relative humidity increases
D . relative humidity decrease
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The rising of the exhaust temperature in manifold pipe may NOT result from （）.
A . too great a loading
B . fouled turbocharger
C . bad combustion
D . excessive air
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Sub-cooling is a method of reducing the temperature of the liquid refrigerant below its （）.
A . freezing point
B . floc point
C . condensing temperature
D . compression temperature
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The flash point of a liquid refers to the temperature （）
A . at which a liquid will give off inflammable vapors
B . at which a liquid will burn steadily
C . at which a liquid will explode
D . that a liquid must reach before it will flow readily
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As the temperature of the air reaches the dew point，（）.
A . rain must develop
B . fog may form
C . it begins to snow
D . water freeze
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When the temperature of the refrigerant flowing out from the condenser is below the condensing temperature, it is said to be （）.
A . dry
B . wet
C . super-cooled
D . superheated
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Do you know the _______ temperature for the growth of plants?
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（In) warm-blooded animals, their body temperature, regardless of the temperature of the an
(In) warm-blooded animals, their body temperature, regardless of the temperature of the animals' (surroundings), (are) maintained within narrow (limits).
A．In
B．surroundings
C．are
D．limits
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Temperature affects the viscosity of oil.（)
是
否
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Most of the pioneers of low-temperature physics expected gases to liquefy, but none of them predicted superconductivity. This phenomenon was discovered in 1911 by Onnes while he was studying frozen mercury.
More than 40 years passed before physicists were able to offer an explanation for superconductivity. The accepted theory, developed in the 1950s, holds that the fundamental behavior. of electrons changes at very low temperatures because of the effects of quantum mechanics. Electrons are tiny particles that make up the outer part of an atom, circling rapidly around the nucleus of the atom. In a regular conductor—a metal that conducts an electric current—the outermost electrons are not bound tightly to the atoms, and so they move around relatively freely. The flow of these electrons is an electric current.
At normal temperatures, a conductor's electrons cannot move completely freely through the metal because they are "bumped around" by the metal's atoms. But according to the leading theory of superconductivity, when a metal is very cold, electrons form. pairs. Then, like couples maneuvering on a crowded dance floor but never colliding, the paired electrons are able to move unimpeded through the metal. In pairing up, it seems, the electrons are able to "blend together" and move in unison without resistance. This explanation seems to account for superconductivity at extremely low temperatures, but in 1986 scientists in Switzerland found that some metal-containing ceramics are superconductors at much higher temperatures. By 1992, scientists had developed ceramics that become superconducting at - 297'F, and some researchers speculated that room-temperature superconductors may be possible. Scientists are still trying to formulate a theory for high-temperature superconductivity.
The new ceramic materials can be maintained at their superconducting temperatures, with relatively inexpensive liquid nitrogen rather than the much colder and much more costly liquid helium required by metal superconductors. The cost difference could make superconductivity practical for many new technologies. For example, magnetically levitated trains, which require superconducting electromagnets, would be much cheaper to build than they are now. Superconducting devices might also be used for advanced power transmission lines and in new types of compact, ultrafast computers. But for the time being, superconductivity is finding application mostly in scientific research and in some kinds of medical imaging devices.
The flow of an electric current in a regular conductor is made possible by the fact that______.
A．electrons circle rapidly around the atom
B．the outermost electron move relatively freely around the atom
C．the innermost electrons stick to the atom
D．the outermost electrons are bound tightly to the inner ones
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The （） the temperature, the greater the retardation of food degradation
