课程咨询
扫码关注掌握一手留学资讯

扫码关注掌握一手留学资讯

回复XDF免费领

水平测试和备考资料

扫码关注公众号

GRE阅读题目解析:断层扫描技术

2017-01-16 16:42:00来源:网络

  GRE阅读题目解析:断层扫描技术】GRE考试考什么?GRE阅读是重点。新东方在线GRE频道为大家带来GRE阅读题目解析:断层扫描技术,答案见下一页,希望对大家GRE备考有所帮助。更多精彩尽请关注新东方在线GRE频道!

  查看全部:GRE阅读答案解析(汇总)

  GRE阅读题目解析:断层扫描技术

  P4

  In medical tomography x-rays map the human body's density variations (and hence internal organs); the information from the x-rays, transmitted through the body along many different paths, is recombined to form three-dimensional images of the body's interior. It is primarily this multiplicative increase in data obtained from the multipath transmission of signals that accounts for oceanographers' attraction to tomography.

  Researchers reasoned that low-frequency sound waves, because they are so well described mathematically and because even small perturbations in emitted sound waves can be detected, could be transmitted through the ocean over many different paths and that the properties of the ocean's interior could be deduced on the basis of how the ocean altered the signals. Their initial trials were highly successful, and ocean acoustic tomography was born. (128 words)

  8.Which of the following, if presented as the first sentence of a succeeding paragraph, would most logically continue the discussion presented in the passage?

  (A) Timekeeping in medical tomography must be precise because the changes in travel time caused by density fluctuations are slight.

  (B) To understand how ocean acoustic tomography works, it is necessary to know how sound travels in the ocean.

  (C) Ships are another possibility. but they would need to stop every 50 kilometers to lower measuring instruments.

  (D) These variations amount to only about 2 to 3 percent of the average speed of sound in water, which is about 1,500 meters per second.

  (E) The device used in medical tomography emits a specially coded signal, easily distinguishable from background noise

  点击下一页查看答案:

本文关键字: GRE阅读 GRE阅读真题

添加新东方美研助教回复【GRE】获取

模考真题|写作题库|阅读机经|佛脚词汇

更多资料
更多>>
更多内容

关注新东方美研助教

回复【GRE】获取备考必看资料包

新东方美研备考资料
GRE录播课(全科班/单项班) GMAT6-8人直播VIP小班 托福直播精讲班(30天/60天)
更多>>
更多惊喜>>
更多>>
更多资料