2014考研英语阅读经典试题及答案(17)
<p> <span word="SAMPLE">SAMPLE</span> 17</p><p> [物理学]</p><p> <span word="The">The</span> <span word="intensive">intensive</span> <span word="work">work</span> <span word="of">of</span> <span word="materials">materials</span> <span word="scientists">scientists</span> <span word="and">and</span> <span word="solid">solid</span>-<span word="state">state</span> <span word="physicists">physicists</span> <span word="has">has</span> <span word="given">given</span> <span word="rise">rise</span> <span word="to">to</span> <span word="a">a</span> <span word="class">class</span> <span word="of">of</span> <span word="solids">solids</span> <span word="known">known</span> <span word="as">as</span> <span word="amorphous">amorphous</span> <span word="metallic">metallic</span> <span word="alloys">alloys</span> <span word="or">or</span> <span word="glassy">glassy</span> <span word="metals">metals</span>. <span word="There">There</span> <span word="is">is</span> <span word="a">a</span> <span word="growing">growing</span> <span word="interest">interest</span> <span word="among">among</span> <span word="theoretical">theoretical</span> <span word="and">and</span> <span word="applied">applied</span> <span word="researchers">researchers</span> <span word="alike">alike</span> <span word="in">in</span> <span word="the">the</span> <span word="structural">structural</span> <span word="properties">properties</span> <span word="of">of</span> <span word="these">these</span> <span word="materials">materials</span>.</p><p> <span word="When">When</span> <span word="a">a</span> <span word="molten">molten</span> <span word="metal">metal</span> <span word="or">or</span> <span word="metallic">metallic</span> <span word="alloy">alloy</span> <span word="is">is</span> <span word="cooled">cooled</span> <span word="to">to</span> <span word="a">a</span> <span word="solid">solid</span>, <span word="a">a</span> <span word="crystalline">crystalline</span> <span word="structure">structure</span> <span word="is">is</span> <span word="formed">formed</span> <span word="that">that</span> <span word="depends">depends</span> <span word="on">on</span> <span word="the">the</span> <span word="particular">particular</span> <span word="alloy">alloy</span> <span word="composition">composition</span>. <span word="In">In</span> <span word="contrast">contrast</span>, <span word="molten">molten</span> <span word="nonmetallic">nonmetallic</span> <span word="glass">glass</span>-<span word="forming">forming</span> <span word="materials">materials</span> <span word="when">when</span> <span word="cooled">cooled</span> <span word="do">do</span> <span word="not">not</span> <span word="assume">assume</span> <span word="a">a</span> <span word="crystalline">crystalline</span> <span word="structure">structure</span>, <span word="but">but</span> <span word="instead">instead</span> <span word="retain">retain</span> <span word="a">a</span> <span word="structure">structure</span> <span word="somewhat">somewhat</span> <span word="like">like</span> <span word="that">that</span> <span word="of">of</span> <span word="the">the</span> <span word="liquid">liquid</span><span word="an">an</span> <span word="amorphous">amorphous</span> <span word="structure">structure</span>. <span word="At">At</span> <span word="room">room</span> <span word="temperature">temperature</span> <span word="the">the</span> <span word="natural">natural</span> <span word="long">long</span>-<span word="term">term</span> <span word="tendency">tendency</span> <span word="for">for</span> <span word="both">both</span> <span word="types">types</span> <span word="of">of</span> <span word="materials">materials</span> <span word="is">is</span> <span word="to">to</span> <span word="assume">assume</span> <span word="the">the</span> <span word="crystalline">crystalline</span> <span word="structure">structure</span>. <span word="The">The</span> <span word="difference">difference</span> <span word="between">between</span> <span word="the">the</span> <span word="two">two</span> <span word="is">is</span> <span word="in">in</span> <span word="the">the</span> <span word="kinetics">kinetics</span> <span word="or">or</span> <span word="rate">rate</span> <span word="of">of</span> <span word="formation">formation</span> <span word="of">of</span> <span word="the">the</span> <span word="crystalline">crystalline</span> <span word="structure">structure</span> <span word="which">which</span> <span word="is">is</span> <span word="controlled">controlled</span> <span word="by">by</span> <span word="factors">factors</span> <span word="such">such</span> <span word="as">as</span> <span word="the">the</span> <span word="nature">nature</span> <span word="of">of</span> <span word="the">the</span> <span word="chemical">chemical</span> <span word="bonding">bonding</span> <span word="and">and</span> <span word="the">the</span> <span word="ease">ease</span> <span word="with">with</span> <span word="which">which</span> <span word="atoms">atoms</span> <span word="move">move</span> <span word="relative">relative</span> <span word="to">to</span> <span word="each">each</span> <span word="other">other</span>. <span word="Thus">Thus</span>, <span word="in">in</span> <span word="metals">metals</span>, <span word="the">the</span> <span word="kinetics">kinetics</span> <span word="favors">favors</span> <span word="rapid">rapid</span> <span word="formation">formation</span> <span word="of">of</span> <span word="a">a</span> <span word="crystallines">crystallines</span> <span word="structure">structure</span> <span word="whereas">whereas</span> <span word="in">in</span> <span word="nonmetallic">nonmetallic</span> <span word="glasses">glasses</span> <span word="the">the</span> <span word="rate">rate</span> <span word="of">of</span> <span word="formation">formation</span> <span word="is">is</span> <span word="so">so</span> <span word="slow">slow</span> <span word="that">that</span> <span word="almost">almost</span> <span word="any">any</span> <span word="cooling">cooling</span> <span word="rate">rate</span> <span word="is">is</span> <span word="sufficient">sufficient</span> <span word="to">to</span> <span word="result">result</span> <span word="in">in</span> <span word="an">an</span> <span word="amorphous">amorphous</span> <span word="structure">structure</span>. <span word="For">For</span> <span word="glassy">glassy</span> <span word="metals">metals</span> <span word="to">to</span> <span word="be">be</span> <span word="formed">formed</span>, <span word="the">the</span> <span word="molten">molten</span> <span word="metal">metal</span> <span word="must">must</span> <span word="be">be</span> <span word="cooled">cooled</span> <span word="extremely">extremely</span> <span word="rapidly">rapidly</span> <span word="so">so</span> <span word="that">that</span> <span word="crystallization">crystallization</span> <span word="is">is</span> <span word="suppressed">suppressed</span>.</p><p> <span word="The">The</span> <span word="structure">structure</span> <span word="of">of</span> <span word="glassy">glassy</span> <span word="metals">metals</span> <span word="is">is</span> <span word="thought">thought</span> <span word="to">to</span> <span word="be">be</span> <span word="similar">similar</span> <span word="to">to</span> <span word="that">that</span> <span word="of">of</span> <span word="liquid">liquid</span> <span word="metals">metals</span>. <span word="One">One</span> <span word="of">of</span> <span word="the">the</span> <span word="first">first</span> <span word="attempts">attempts</span> <span word="to">to</span> <span word="model">model</span> <span word="the">the</span> <span word="structure">structure</span> <span word="of">of</span> <span word="a">a</span> <span word="liquid">liquid</span> <span word="was">was</span> <span word="that">that</span> <span word="by">by</span> <span word="the">the</span> <span word="late">late</span> <span word="J">J</span>. <span word="D">D</span>. <span word="Bernal">Bernal</span> <span word="of">of</span> <span word="the">the</span> <span word="University">University</span> <span word="of">of</span> <span word="London">London</span>, <span word="who">who</span> <span word="packed">packed</span> <span word="hard">hard</span> <span word="spheres">spheres</span> <span word="into">into</span> <span word="a">a</span> <span word="rubber">rubber</span> <span word="vessel">vessel</span> <span word="in">in</span> <span word="such">such</span> <span word="a">a</span> <span word="way">way</span> <span word="as">as</span> <span word="to">to</span> <span word="obtain">obtain</span> <span word="the">the</span> <span word="maximum">maximum</span> <span word="possible">possible</span> <span word="density">density</span>. <span word="The">The</span> <span word="resulting">resulting</span> <span word="dense">dense</span>, <span word="random">random</span>-<span word="packed">packed</span> <span word="structure">structure</span> <span word="was">was</span> <span word="the">the</span> <span word="basis">basis</span> <span word="for">for</span> <span word="many">many</span> <span word="attempts">attempts</span> <span word="to">to</span> <span word="model">model</span> <span word="the">the</span> <span word="structure">structure</span> <span word="of">of</span> <span word="glassy">glassy</span> <span word="metals">metals</span>.</p>
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