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单选题
The energy for pushing this piston up can be supplied from （）, so that the piston can keep moving up and down.
A
the same piston
B
the piston nearby
C
the other pistons
D
the generators on board
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考题
The upper piston rings m large, slow-speed, two-stroke/cycle diesel engines are most effectively lubricated by oil ____.A.fed from mechanical lubricatorsB.thrown off from the main bearingsC.supplied from wick fed drip lubricatorsD.flow from a centrifugal or banjo oiler
考题
材料：A typical example of a hydraulic governor is the Woodward. This has adjustable droop for parallel operation and it is fitted with a speed-adjusting control . If required it can be fitted with a synchronizing motor to provide remote control from a switchboard.A gear pump driven from the engine supplies oil under pressure to accumulator pistons under which is a by-pass to regulate maximum pressure. One branch supplies oil which acts on top of the power piston, the pressure always tending to turn the terminal shaft to shut off fuel, while the other branch supplies oil to the pilot valve which is operated by the linkage from the fly weights above.Should the speed of the engine decrease due to increased load the flyweights will move towards their center of rotation and lower the position of the pilot valve plunger, admitting oil pressure from the bottom of the power piston. Since, however, the area on the bottom is much greater than the top the net resultant force causes the piston to move upwards. This operates the power lever turning the terminal shaft which varies the cut-off point in the fuel pump through linkage, but as the power piston moves up, the actuating compensating piston moves down.Oil under this piston is now forced through the needle valve to the receiving compensating piston, raising the outer end of the floating lever and the pilot valve plunger until it has returned to its normal position. This stops further movement of the terminal shaft so that the fuel control is now set in a position corresponding to the increased fuel required to run the engine at normal speed under the increased load.问题：This passage is mainly about ___.A.what type of governor should be provided when the engine is used for electric power generationB.why the speed of the engine fluctuatesC.how the governor worksD.how the fuel pumps workThe oil from the gear pump will ___. ① be supplied to the accumulator ② act on the power piston ③ be supplied to the pilot valveA.①B.①②C.②③D.①②③Which of the following is true about the Woodward discussed?A.It is a kind of mechanical governor.B.It can not be used for parallel operation.C.It has speed droop.D.It may only be manually controlled from a switch boarE.When the speed of the engine decreases due to increased load, which of the following will NOT happen?A.The flyweights move towards their centerB.The pilot valve plunger moves towards its normal positionC.The power piston moves downwards until it returns to its normal positionD.The terminal shaft moves to a new position请帮忙给出每个问题的正确答案和分析，谢谢！
考题
共用题干
Electromagnetic Energy1 White light seems to be a combination of all colors.The energy that comes from a source of light is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy day it is possible to get a sunburn even though you feel cool.Visible light and the kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.2 The sun is 93 million miles from the earth.Yet we can use energy from the sun because electromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals travel from transmitters to receivers as low-energy electromagnetic waves.Infrared（红外线的）radiation is an electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light have more energy than waves of radio,television,or radar.Ultraviolet rays（紫外线）and X-rays are electromagnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating buildings. Sunlight and electric lights are part of our requirements for normal living.Ultraviolet radiation is useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel through solid objects. They can be used to detect and treat cancer.X-rays are used in industry to find hidden cracks in metal,and in medicine to reveal broken bones.4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but the energy stored in coal came from the sun,too.5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the theory was proposed , nuclear energy was harnessed（利用）by man.Chemical energy comes from electron （电子）rearrangement.Nuclear energy comes from a change in the nucleus of an atom.Compared with chemical reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.6 Nuclear energy is beginning to compete with coal as an economical source of'power to generate electricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.Infrared radiation can produce heat______. A:when it is absorbed by matterB:when it is cloudyC:because they can pass through solid objectsD:when the sunrays are fierce.E:when a change in the nucleus of an atom takes placeF:when electron rearrangement takes place
考题
共用题干
Electromagnetic Energy1 White light seems to be a combination of all colors.The energy that comes from a source of light is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy day it is possible to get a sunburn even though you feel cool.Visible light and the kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.2 The sun is 93 million miles from the earth.Yet we can use energy from the sun because electromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals travel from transmitters to receivers as low-energy electromagnetic waves.Infrared（红外线的）radiation is an electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light have more energy than waves of radio,television,or radar.Ultraviolet rays（紫外线）and X-rays are electromagnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating buildings. Sunlight and electric lights are part of our requirements for normal living.Ultraviolet radiation is useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel through solid objects. They can be used to detect and treat cancer.X-rays are used in industry to find hidden cracks in metal,and in medicine to reveal broken bones.4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but the energy stored in coal came from the sun,too.5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the theory was proposed , nuclear energy was harnessed（利用）by man.Chemical energy comes from electron （电子）rearrangement.Nuclear energy comes from a change in the nucleus of an atom.Compared with chemical reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.6 Nuclear energy is beginning to compete with coal as an economical source of'power to generate electricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.X-rays and gamma rays can be used to detect and treat cancer______.A:when it is absorbed by matterB:when it is cloudyC:because they can pass through solid objectsD:when the sunrays are fierce.E:when a change in the nucleus of an atom takes placeF:when electron rearrangement takes place
考题
共用题干
Electromagnetic Energy1 White light seems to be a combination of all colors.The energy that comes from a source of light is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy day it is possible to get a sunburn even though you feel cool.Visible light and the kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.2 The sun is 93 million miles from the earth.Yet we can use energy from the sun because electromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals travel from transmitters to receivers as low-energy electromagnetic waves.Infrared（红外线的）radiation is an electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light have more energy than waves of radio,television,or radar.Ultraviolet rays（紫外线）and X-rays are electromagnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating buildings. Sunlight and electric lights are part of our requirements for normal living.Ultraviolet radiation is useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel through solid objects. They can be used to detect and treat cancer.X-rays are used in industry to find hidden cracks in metal,and in medicine to reveal broken bones.4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but the energy stored in coal came from the sun,too.5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the theory was proposed , nuclear energy was harnessed（利用）by man.Chemical energy comes from electron （电子）rearrangement.Nuclear energy comes from a change in the nucleus of an atom.Compared with chemical reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.6 Nuclear energy is beginning to compete with coal as an economical source of'power to generate electricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.Chemical energy is generated______. A:when it is absorbed by matterB:when it is cloudyC:because they can pass through solid objectsD:when the sunrays are fierce.E:when a change in the nucleus of an atom takes placeF:when electron rearrangement takes place
考题
共用题干
Electromagnetic Energy1 White light seems to be a combination of all colors.The energy that comes from a source of light is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudyday it is possible to get a sunburn even though you feel cool.Visible light and the kind of energy that produce warmth and sunburn are examples of electromagnetic energy.2 The sun is 93 million miles away from the earth.Yet we can use energy from the sun because elec-tromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals travel from transmitters to receivers as low-energy electromagnetic waves. Infrared（红外线的）radiation is an electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light have more energy than waves of radio , television , or radar. Ultraviolet rays（紫外线）and X-rays are electro- magnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating buildings.Sunlight and electric lights are part of our requirements for normal living. Ultraviolet radiation is useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel right through solid objects.They can be used to detect and treat cancer. X-rays are used in industry to find hidden cracks in metal,and in medicine to reveal broken bones.4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but the energy stored in coal came from the sun,too.5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If the.sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the theory was proposed , nuclear energy was harnessed（利用）by man. Chemical energy comes from electron （电子）rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemi-cal reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.6 Nuclear energy is beginning to compete with coal as an economical source of power to generate elec-tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.We can use energy from the sun because_____________.A:electromagnetic energyB:electromagnetic energy travels through spaceC:came from the sunD:when a change in the nucleus of an atom takes placeE:when the sunrays are fierceF:chemical energy is generated
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Green Energy1.Green energy is energy that is produced in a manner that has, less of a negative impact to the environment than energy sources like fossil fuels,which are often produced with harmful side effects."Greener" types of energy that often come to mind are solar,wind,geothermal and hydro energy.There are several more,even including nuclear energy,that is sometimes considered a green energy source because of its lower waste output relative to energy sources such as coal or oil.2.The goal of green energy is generally to create power with as little pollution as possible produced as a by-product. Every form of energy collection will result in some pollution,but those that are green are known to cause less than those that are not. Most people who advocate greener sources of energy claim that the result of worldwide use of green energy will result in the ability to preserve the planet for a longer time.Greenhouse gases,a by-product of traditional sources of energy such as fossil fuels are thought to be causing global warming,or the process of the Earth heating up at an accelerated pace.3.It is not completely necessary for green energy sources to come from places like solar or wind fields,which are examples of green"power plants".A green energy source can be a building that is designed in a way that it keeps itself cool in the daytime and heated in the night through its architectural design rather than having an air-conditioning or a heating system. The conservation of energy through architectural（建筑学的）design becomes, itself, a green energy source. Similarly, many sources of green energy can come directly from the area in which the energy is needed rather than from an outside source.4.One of the goals of green energy technology is to take existing fossil fuel energy technology and clean it up so it is produced more cleanly. One such case is that of clean coal technology,where scientists are trying to find ways to extract energy from coal and other fossil fuels without all of the harmful side effects.The success of such these types of green energy depend upon the ability to extract harmful by-products from fossil fuels while not only being energy efficient,but by being cost efficient as well.Greenhouse gases are thought to be causing______.A:global warmingB:carbon emissionC:lower waste outputD:a green energy sourceE:fossil fuels F: clean fuels
考题
共用题干
Green Energy1.Green energy is energy that is produced in a manner that has, less of a negative impact to the environment than energy sources like fossil fuels,which are often produced with harmful side effects."Greener" types of energy that often come to mind are solar,wind,geothermal and hydro energy.There are several more,even including nuclear energy,that is sometimes considered a green energy source because of its lower waste output relative to energy sources such as coal or oil.2.The goal of green energy is generally to create power with as little pollution as possible produced as a by-product. Every form of energy collection will result in some pollution,but those that are green are known to cause less than those that are not. Most people who advocate greener sources of energy claim that the result of worldwide use of green energy will result in the ability to preserve the planet for a longer time.Greenhouse gases,a by-product of traditional sources of energy such as fossil fuels are thought to be causing global warming,or the process of the Earth heating up at an accelerated pace.3.It is not completely necessary for green energy sources to come from places like solar or wind fields,which are examples of green"power plants".A green energy source can be a building that is designed in a way that it keeps itself cool in the daytime and heated in the night through its architectural design rather than having an air-conditioning or a heating system. The conservation of energy through architectural（建筑学的）design becomes, itself, a green energy source. Similarly, many sources of green energy can come directly from the area in which the energy is needed rather than from an outside source.4.One of the goals of green energy technology is to take existing fossil fuel energy technology and clean it up so it is produced more cleanly. One such case is that of clean coal technology,where scientists are trying to find ways to extract energy from coal and other fossil fuels without all of the harmful side effects.The success of such these types of green energy depend upon the ability to extract harmful by-products from fossil fuels while not only being energy efficient,but by being cost efficient as well.Paragraph 3______A:Why Do We Develop Green Energy?B:What Is the Goal of Green Energy?C:What Is the Weakness of Green Energy?D:What Is a Green Energy?E:How Much Does the Green Energy Cost Every Year?F: How Many Kinds of Green Energy We Can Take Use of?
考题
共用题干
Green Energy1.Green energy is energy that is produced in a manner that has, less of a negative impact to the environment than energy sources like fossil fuels,which are often produced with harmful side effects."Greener" types of energy that often come to mind are solar,wind,geothermal and hydro energy.There are several more,even including nuclear energy,that is sometimes considered a green energy source because of its lower waste output relative to energy sources such as coal or oil.2.The goal of green energy is generally to create power with as little pollution as possible produced as a by-product. Every form of energy collection will result in some pollution,but those that are green are known to cause less than those that are not. Most people who advocate greener sources of energy claim that the result of worldwide use of green energy will result in the ability to preserve the planet for a longer time.Greenhouse gases,a by-product of traditional sources of energy such as fossil fuels are thought to be causing global warming,or the process of the Earth heating up at an accelerated pace.3.It is not completely necessary for green energy sources to come from places like solar or wind fields,which are examples of green"power plants".A green energy source can be a building that is designed in a way that it keeps itself cool in the daytime and heated in the night through its architectural design rather than having an air-conditioning or a heating system. The conservation of energy through architectural（建筑学的）design becomes, itself, a green energy source. Similarly, many sources of green energy can come directly from the area in which the energy is needed rather than from an outside source.4.One of the goals of green energy technology is to take existing fossil fuel energy technology and clean it up so it is produced more cleanly. One such case is that of clean coal technology,where scientists are trying to find ways to extract energy from coal and other fossil fuels without all of the harmful side effects.The success of such these types of green energy depend upon the ability to extract harmful by-products from fossil fuels while not only being energy efficient,but by being cost efficient as well.The success of green energy depend upon the ability to extract harmful by-products from______.A:global warmingB:carbon emissionC:lower waste outputD:a green energy sourceE:fossil fuels F: clean fuels
考题
共用题干
Green Energy1.Green energy is energy that is produced in a manner that has, less of a negative impact to the environment than energy sources like fossil fuels,which are often produced with harmful side effects."Greener" types of energy that often come to mind are solar,wind,geothermal and hydro energy.There are several more,even including nuclear energy,that is sometimes considered a green energy source because of its lower waste output relative to energy sources such as coal or oil.2.The goal of green energy is generally to create power with as little pollution as possible produced as a by-product. Every form of energy collection will result in some pollution,but those that are green are known to cause less than those that are not. Most people who advocate greener sources of energy claim that the result of worldwide use of green energy will result in the ability to preserve the planet for a longer time.Greenhouse gases,a by-product of traditional sources of energy such as fossil fuels are thought to be causing global warming,or the process of the Earth heating up at an accelerated pace.3.It is not completely necessary for green energy sources to come from places like solar or wind fields,which are examples of green"power plants".A green energy source can be a building that is designed in a way that it keeps itself cool in the daytime and heated in the night through its architectural design rather than having an air-conditioning or a heating system. The conservation of energy through architectural（建筑学的）design becomes, itself, a green energy source. Similarly, many sources of green energy can come directly from the area in which the energy is needed rather than from an outside source.4.One of the goals of green energy technology is to take existing fossil fuel energy technology and clean it up so it is produced more cleanly. One such case is that of clean coal technology,where scientists are trying to find ways to extract energy from coal and other fossil fuels without all of the harmful side effects.The success of such these types of green energy depend upon the ability to extract harmful by-products from fossil fuels while not only being energy efficient,but by being cost efficient as well.Nuclear energy is sometimes considered a green energy source because of its______.A:global warmingB:carbon emissionC:lower waste outputD:a green energy sourceE:fossil fuels F: clean fuels
考题
共用题干
Green Energy1.Green energy is energy that is produced in a manner that has, less of a negative impact to the environment than energy sources like fossil fuels,which are often produced with harmful side effects."Greener" types of energy that often come to mind are solar,wind,geothermal and hydro energy.There are several more,even including nuclear energy,that is sometimes considered a green energy source because of its lower waste output relative to energy sources such as coal or oil.2.The goal of green energy is generally to create power with as little pollution as possible produced as a by-product. Every form of energy collection will result in some pollution,but those that are green are known to cause less than those that are not. Most people who advocate greener sources of energy claim that the result of worldwide use of green energy will result in the ability to preserve the planet for a longer time.Greenhouse gases,a by-product of traditional sources of energy such as fossil fuels are thought to be causing global warming,or the process of the Earth heating up at an accelerated pace.3.It is not completely necessary for green energy sources to come from places like solar or wind fields,which are examples of green"power plants".A green energy source can be a building that is designed in a way that it keeps itself cool in the daytime and heated in the night through its architectural design rather than having an air-conditioning or a heating system. The conservation of energy through architectural（建筑学的）design becomes, itself, a green energy source. Similarly, many sources of green energy can come directly from the area in which the energy is needed rather than from an outside source.4.One of the goals of green energy technology is to take existing fossil fuel energy technology and clean it up so it is produced more cleanly. One such case is that of clean coal technology,where scientists are trying to find ways to extract energy from coal and other fossil fuels without all of the harmful side effects.The success of such these types of green energy depend upon the ability to extract harmful by-products from fossil fuels while not only being energy efficient,but by being cost efficient as well.The conservation of energy through architectural design becomes______.A:global warmingB:carbon emissionC:lower waste outputD:a green energy sourceE:fossil fuels F: clean fuels
考题
We are pleased to inform.you that the item you requested can be supplied（）stock.A、uponB、outC、inD、from
考题
单选题The four-stroke cycle begins with the piston （）.A
coming up from the BDCB
coming up from the TDCC
coming down from the BDCD
coming down from the TDC
考题
单选题Scuffed cylinder liner wearing surfaces in a diesel engines can result from （）A
starting the engine while hotB
knurling the piston skirtC
operating the engine overheatedD
scuff resistant piston rings
考题
单选题For diesel engine piston cooling, lubricating oil can be supplied to the pistons by a/an （）.A
oil sprayB
oil bathC
oil control ringsD
drilled passage through the camshaft
考题
单选题Cracking of a diesel piston crown can result from（）A
Excessive piston to liner clearanceB
The underside of the piston crown being excessively dirty lowering the rate of heat transferC
Faulty nozzle sprayD
All of the above
考题
单选题The two-stroke cycle begins with the piston coming up from the bottom of its stroke, with scavenge ports in the sides of the cylinder being （）.A
shutB
closingC
openedD
closed
考题
单选题The two-stroke cycle begins with the piston coming up from the BDC, with the scavenging ports in the sides of the cylinders being （）.A
openB
uncoverC
coveredD
closed
考题
单选题Scuffed cylinder liner wearing surfaces in a diesel engines can result from （）A
chromium plating piston ringsB
knurling the piston skirtC
extended maximum power operationD
applying load to a cold diesel engine
考题
单选题Oil is supplied to the cylinder wall and （） by means of mechanical lubricators.A
the cylinder coverB
the piston ringsC
the piston crownD
the piston skirt
考题
单选题In a diesel engine, when the fuel is injected into the cylinder,（）A
the piston is just coming upward from the bottom dead centerB
the piston has moved about one-fifth of the way upC
the piston has moved most of the way up and almost reached the TDCD
the piston has just past the TDC
考题
单选题What can we learn from the passage?A
Solar energy itself is expensive.B
Solar power will be used up very soon.C
Solar power is a kind of clean and useful energy.D
Solar power is much better than the other energies.
考题
单选题The rotary motion of a diesel engine crankshaft is obtained from the up and down motion of the piston via the （）.A
camshaftB
reduction gearsC
rocker armD
connecting or piston rod
考题
单选题A diesel engine piston crown can crack from （）A
excessive piston to liner clearanceB
excessive dirt beneath the piston crown that reduces heat transferC
faulty nozzle sprayD
all of the above
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