meili 发表于 2022-10-18 20:15:57

考研优美英语作文的背诵053

<p>  <span word="Nitinol">Nitinol</span></p><p>  <span word="Nitinol">Nitinol</span> is one of the most extraordinary metals to be discoveredthis century: A simple alloy of nickel and titanium, nitinol has someperplexing properties. A metal with a memory, it can be made to remember anyshape into which it is fashioned, returning to that shape whenever it isheated.For example, a piece of nitinol wire bent to form a circle that is thenheated and quenched will remember this shape. It may then be bent or crumpled, but on reheating, will violently untwist,reforming its original shape. This remarkable ability is calledShape Memory Effect; other alloys, such asbrasses, are known to possess it to a limited extent. No one fully understands SME, and nitinol remains particularlyperplexing, for, whenever it performs this peculiar feat, it appearsto be breaking the laws of thermodynamics by springing back into shape withgreater force than was used to deform it in the first place.</p><p>  <span word="But">But</span> <span word="not">not</span> <span word="only">only</span> <span word="is">is</span> <span word="nitinol">nitinol</span> <span word="capable">capable</span> <span word="of">of</span> <span word="remembering">remembering</span>, <span word="it">it</span> <span word="also">also</span> <span word="has">has</span> <span word="the">the</span> <span word="ability">ability</span> <span word="to">to</span> <span word="learn">learn</span>. <span word="If">If</span> <span word="theheating">theheating</span>-<span word="cooling">cooling</span>-<span word="crumpling">crumpling</span>-<span word="reheating">reheating</span> <span word="process">process</span> <span word="is">is</span> <span word="carried">carried</span> <span word="out">out</span> <span word="sufficiently">sufficiently</span> <span word="often">often</span>,<span word="and">and</span> <span word="the">the</span> <span word="metal">metal</span> <span word="is">is</span> <span word="always">always</span> <span word="crumpled">crumpled</span> <span word="in">in</span> <span word="exactly">exactly</span> <span word="the">the</span> <span word="same">same</span> <span word="way">way</span>, <span word="the">the</span> <span word="nitinol">nitinol</span> <span word="willnot">willnot</span> <span word="only">only</span> <span word="remember">remember</span> <span word="its">its</span> <span word="original">original</span> <span word="shape">shape</span>, <span word="but">but</span> <span word="gradually">gradually</span> <span word="it">it</span> <span word="learns">learns</span> <span word="toremember">toremember</span> <span word="its">its</span> <span word="crumpled">crumpled</span> <span word="form">form</span> <span word="as">as</span> <span word="well">well</span>, <span word="and">and</span> <span word="will">will</span> <span word="begin">begin</span> <span word="to">to</span> <span word="return">return</span> <span word="to">to</span> <span word="the">the</span> <span word="samecrumpled">samecrumpled</span> <span word="shape">shape</span> <span word="every">every</span> <span word="time">time</span> <span word="it">it</span> <span word="is">is</span> <span word="cooled">cooled</span>.</p><p>  <span word="Eventually">Eventually</span>, <span word="the">the</span> <span word="metal">metal</span> <span word="will">will</span> <span word="crumple">crumple</span> <span word="and">and</span> <span word="uncrumple">uncrumple</span>,<span word="totally">totally</span> <span word="unaided">unaided</span>, <span word="in">in</span> <span word="response">response</span> <span word="to">to</span> <span word="changes">changes</span> <span word="in">in</span> <span word="temperature">temperature</span> <span word="and">and</span> <span word="without">without</span> <span word="anysign">anysign</span> <span word="of">of</span> <span word="metal">metal</span> <span word="fatigue">fatigue</span>. <span word="Engineers">Engineers</span> <span word="have">have</span> <span word="produced">produced</span> <span word="prototype">prototype</span> <span word="engines">engines</span> <span word="that">that</span> <span word="aredriven">aredriven</span> <span word="by">by</span> <span word="the">the</span> <span word="force">force</span> <span word="of">of</span> <span word="nitinol">nitinol</span> <span word="springing">springing</span> <span word="from">from</span> <span word="one">one</span> <span word="shape">shape</span> <span word="to">to</span> <span word="another">another</span> <span word="as">as</span> <span word="italternately">italternately</span> <span word="encounters">encounters</span> <span word="hot">hot</span> <span word="and">and</span> <span word="cold">cold</span> <span word="water">water</span>. <span word="The">The</span> <span word="energy">energy</span> <span word="from">from</span> <span word="theseremarkable">theseremarkable</span> <span word="engines">engines</span> <span word="is">is</span>, <span word="however">however</span>, <span word="not">not</span> <span word="entirely">entirely</span> <span word="free">free</span>: <span word="heat">heat</span> <span word="energy">energy</span> <span word="is">is</span> <span word="required">required</span> <span word="to">to</span> <span word="produce">produce</span> <span word="the">the</span> <span word="temperature">temperature</span> <span word="differences">differences</span> <span word="needed">needed</span> <span word="to">to</span> <span word="runthe">runthe</span> <span word="engine">engine</span>. <span word="But">But</span> <span word="the">the</span> <span word="optimum">optimum</span> <span word="temperatures">temperatures</span> <span word="at">at</span> <span word="which">which</span> <span word="the">the</span> <span word="metal">metal</span> <span word="reacts">reacts</span> <span word="can">can</span> <span word="becontrolled">becontrolled</span> <span word="by">by</span> <span word="altering">altering</span> <span word="the">the</span> <span word="proportions">proportions</span> <span word="of">of</span> <span word="nickel">nickel</span> <span word="to">to</span> <span word="titanium">titanium</span>; <span word="some">some</span> <span word="alloys">alloys</span> <span word="willeven">willeven</span> <span word="perform">perform</span> <span word="at">at</span> <span word="room">room</span> <span word="temperature">temperature</span>. <span word="The">The</span> <span word="necessary">necessary</span> <span word="temperature">temperature</span> <span word="range">range</span> <span word="between">between</span> <span word="thewarm">thewarm</span> <span word="and">and</span> <span word="the">the</span> <span word="cold">cold</span> <span word="can">can</span> <span word="be">be</span> <span word="as">as</span> <span word="little">little</span> <span word="as">as</span> <span word="twelve">twelve</span> <span word="degrees">degrees</span> <span word="centigrade">centigrade</span>.</p>
页: [1]
查看完整版本: 考研优美英语作文的背诵053