2014卫生类职称英语考前自测练习阅读判断5

更新时间：2015-12-10 11:50:58 来源：|0

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摘要环球整理的2014卫生类职称英语考前自测练习题，希望对大家备考有所帮助

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职称英语最后冲刺，8小时稳拿68分

　　卫生类-阅读判断

　　Image Martian Dust Particles

　　NASA's Phoenix Mars Lander has taken its first-ever picture of a single particle of rusty Martian dust with one of its microscopes. The dust particles of dust was shown at a higher magnification than anything outside of Earth that has been imaged before. The rounded particle measured only about one micrometer, or one millionth of a meter, across.

　　Taking this image required the highest resolution .microscope operated off Earth: and a specially designed device to hold the Martian dust," said Tom Pike, a Phoenix science team member from Imperial College London. "We always knew it was going to be technically very challenging to image particles this small.''

　　The device that imaged the dust speck is called an atomic force microscope, which maps the shape of particles in three dimensions by scanning them with a sharp tip at the end of a spring. The atomic force microscope can detail the shapes of particles as small as about 100 nanometers. And this won't be the last dust particle that Phoenix will images. "After this first success, we're now working on building up a portrait gallery of the dust on Mars," Pike said.

　　Dust exists everywhere on Mars, coating the surface and giving it its rusty red color. Dust particles also color the Martian sky pink and feed storms that regularly envelope the planet. The ultra-fine dust is the medium that actively links gases in the Martian atmosphere to processes in Martian soil, so it is critically important to understanding Mars' environments, the researchers said.

　　The $420-million Phoenix mission is analyzing the dust and subsurface ice layers of Mars' arctic regions to look for signs of potential past habitability. The particle seen in the atomic force microscope image was part of a sample scooped by the robotic arm from the "Snow White" trench and delivered to Phoenix's microscope Station in early July.

　　练习：

　　1. The dust particle on Mars is the smallest particle that has been imaged outside of Earth.