2015考研英语阅读印刷未来
<p> <span word="An">An</span> <span word="image">image</span> <span word="of">of</span> <span word="the">the</span> <span word="future">future</span></p><p> 印刷未来</p><p> <span word="One">One</span> <span word="of">of</span> <span word="the">the</span> <span word="biggest">biggest</span> <span word="manufacturers">manufacturers</span> <span word="in">in</span> <span word="the">the</span> <span word="worldgives">worldgives</span> 3<span word="D">D</span> <span word="printing">printing</span> <span word="a">a</span> <span word="go">go</span></p><p> 世界龙头机器制造商用3<span word="D">D</span>印刷术进行了一次格外成功的应用</p><p> <span word="ULTRASOUND">ULTRASOUND</span> <span word="scanners">scanners</span> <span word="are">are</span> <span word="used">used</span> <span word="for">for</span> <span word="tasks">tasks</span> <span word="as">as</span> <span word="diverse">diverse</span> <span word="as">as</span> <span word="examining">examining</span> <span word="unborn">unborn</span> <span word="babies">babies</span> <span word="andsearching">andsearching</span> <span word="for">for</span> <span word="cracks">cracks</span> <span word="in">in</span> <span word="the">the</span> <span word="fabric">fabric</span> <span word="of">of</span> <span word="aircraft">aircraft</span>.</p><p> 超声波扫描器的应用领域很广，小到用于检查胎儿，大到飞行器机体瑕疵检测等。</p><p> <span word="They">They</span> <span word="work">work</span> <span word="by">by</span> <span word="sending">sending</span> <span word="out">out</span> <span word="pulses">pulses</span> <span word="of">of</span> <span word="high">high</span>-<span word="frequency">frequency</span> <span word="sound">sound</span> <span word="and">and</span> <span word="then">then</span> <span word="interpreting">interpreting</span> <span word="thereflections">thereflections</span> <span word="as">as</span> <span word="images">images</span>.</p><p> 机理过程是，通过发射高频声波脉冲信号对反射信号进行成像解读。</p><p> <span word="To">To</span> <span word="do">do</span> <span word="all">all</span> <span word="this">this</span>, <span word="though">though</span>, <span word="you">you</span> <span word="need">need</span> <span word="a">a</span> <span word="device">device</span> <span word="called">called</span> <span word="a">a</span> <span word="transducer">transducer</span>.</p><p> 但完成该过程，你不能缺少一台叫做压电式换能器的设备。</p><p> <span word="Transducers">Transducers</span> <span word="are">are</span> <span word="made">made</span> <span word="from">from</span> <span word="arrays">arrays</span> <span word="of">of</span> <span word="tinypiezoelectric">tinypiezoelectric</span> <span word="structures">structures</span> <span word="that">that</span> <span word="convert">convert</span> <span word="electrical">electrical</span> <span word="signals">signals</span> <span word="into">into</span> <span word="ultrasound">ultrasound</span> <span word="waves">waves</span> <span word="by">by</span> <span word="vibrating">vibrating</span> <span word="atan">atan</span> <span word="appropriate">appropriate</span> <span word="frequency">frequency</span>.</p><p> 压电式换能器是由具有压电效应的一系列敏感元件机构组成。敏感元件机构通过定频震荡将电信号转换成超声波。</p><p> <span word="Their">Their</span> <span word="shape">shape</span> <span word="focuses">focuses</span> <span word="the">the</span> <span word="waves">waves</span> <span word="so">so</span> <span word="that">that</span> <span word="they">they</span> <span word="penetrate">penetrate</span> <span word="the">the</span> <span word="object">object</span> <span word="being">being</span> <span word="scanned">scanned</span>.</p><p> 机构的特定外形可聚焦超声波，对被扫描的物体产生穿透作用。</p>
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