大學(xué)英語往年六級真題(編輯修改稿)
2025-04-13 21:21 本頁面
【文章內(nèi)容簡介】 an existing ten kilometer line, drawing tourists and perhaps offering city muters a green alternative to their cars. Councilman wants to build an array of solar magnifying mirrors at one end of the line to collect and focus heat onto water filled tubes. This would generate steam that could be used to fill tanks on a small steam train without the use of fire. Supplying power to trains in this way would offer the shortest distance from well to wheels, he says, with the least amount of energy lost, according to harry valentine, a Canadian engineer who was researching modern steam technology, a special tank measuring two by ten meters could store over seven hundred and fifty kilowatt hours of energy as high pressure steam enough to pull a two car train for an hour or so. Energy to drive a steam lootive can be stored in other materials besides water. For example, a team at Tohoku University in japan has studied materials that can store large amounts of heat. When he did, these materials turned from a solid into a liquid, absorbing energy as they change phase. The liquid is maintained above its melting point until steam is required, at which point the liquid is allowed to turn back into a solid, releasing its stored energy. Another team at Nagoya University in japan has tested calcium pound as an energy storage material, heating this chemical pound drives off carbon dioxide gas, leaving calcium oxide. The gas can be stored under pressure in a tank to recover the energy. The gas is bent back over the calcium oxide. In theory, says Valentine, this can create a high enough temperature to generate su
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