单词：concave reflector
单词：concave reflector 相关文章
In 1970, the Soviet Union put a laser reflector on the moon, carried by a rover. A few months later, it disappeared. Some speculated that the rover had fallen into a crater or parked in such a way as to render the reflector inaccessible. Now after 40
Scientific American(四)月
据《科学》杂志报道，苏联的月球车40年前在月球表面留下了激光反射器，虽然经过多年的搜寻科学家始终没有发现激光反射器的踪迹。 4月22日，一组物理学家终于发现了来自反射器的微弱闪
60秒科学
Gain - This is an increase in signal power, due to a boost from an electronic device. Garbage - These are unwanted characters that appear because of either incorrect settings or noise. Gate - These ar
电信英语
The Five-hundred-meter wide Aperture Spherical Telescope, or FAST, is now operational in the mountains of Guizhou in southwest China. FAST has been designed to help Chinese researchers better understand our universe, as well as probe the cosmos for e
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Bart's upstairs neighbor was driving him nuts. He made all kinds of strange noises at all kinds of strange hours. If I tell my neighbor he's noisy, he won't believe me, Bart thought. He'll believe me only if he lives downstairs and hears himself upst
英文短篇故事（纽约）
By Paul Sisco Washington 14 November 2007 At the McDonald Observatory in western Texas, a unique space program has been quietly underway for more than 30 years. It is called the Lunar Laser Ranging Program. VOA's Paul Sisco has more. Research scienti
VOA常速英语2007年（十一月）
汉字是由笔画构成的。笔画是书写工具在书写面上的运动，大概有三十种不同类型，有些是基本笔画，有些是复杂笔画。笔画对学习汉字以及书法都有重要作用。下面分别说明。注意，笔画的
英文语法词汇
The construction of the project was started in 2011 with an investment of 1.2-billion yuan, or about 180 million US dollars. The 500 metre Aperture Spherical Telescope, or FAST, is the size of 30 football fields. It's located in a hollow that was for
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