单词:acoustical reflector
单词:acoustical 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
This is Scientific American's 60-second Science. I'm Steve Mirsky. Got a minute? Can you name those notes? Probably not. Perhaps one in ten thousand speakers of European languages has perfect pitch - the ability to recognize a note without having hea
This is Scientific American's 60-second Science. I'm Karen Hopkin. If you ever got picked on in the schoolyard, you might have wished for some sort of superpower, like unbeatable speed or maybe just the ability to completely disappear. Now scientists
Scientists analyzed around 2,500 of those calls, and found that the second part (sound) is nearly identical in pitch every time from each whale: 16 hertz, or four octaves below middle C. And the slight variations in frequency that do exist are only a
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
Hybrid cars are good for the environment. But scientists say that they might be bad for pedestrians. Because hybrids are so quiet, it can be hard for walkers to hear them until its too late. Listen to this. [quiet car sound] Thats a Toyota Prius mov
Can you name those notes? Probably notperhaps one in 10,000 speakers of European languages has perfect pitch, the ability to recognize a note without having heard any reference note first. But theres a much better chance you could successfully name
If you ever got picked on in the schoolyard, you might have wished for some sort of superpower: like unbeatable speed or maybe just the ability to completely disappear. Now scientists at the College of Wooster in Ohio say that you might have had a s
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
This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute. Every year, scores of manatees are killed by boats in Floridas waters. Their plight is an ecological concern. And everyone from marine biologists to Marg
This is Scientific American's 60-second Science. I'm Karen Hopkin. This will just take a minute. Hybrid cars are good for the environment, but scientists say that they might be bad for pedestrians. Because hybrids are so quiet that can be hard for wa
We humans are pretty good at communicating with sounds other than words. But how much of this is hard-wired, and how much do we pick up from others? To find out, researchers recorded the nonverbal sounds of people born deaf, as they responded to a ra
Blue whales off the California coast make calls that, sped up 10 times, sound like (sound of two-part call). The original is a wall-rattling frequency too low for us to hear. Scientists analyzed around 2,500 of those calls, and found that the second
Country Music Ladies Put Men in Their Place American country music lyrics often describe women as they might appear in mens dreams. This is especially true of songs by many male artists. But the songs by Maddie Marlow and Tae Dye are different. The t
The Tiangong-2 space lab, though adopting the structure of Tiangong-1 without too many changes in appearance, has been designed to function much stronger than its predecessor. Zhu Congpeng, chief designer of the lab, says they've focused on a variety
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
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
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
通知与确认 Acknowledgments Confirmations 通知对方接到来信Acknowledging receipt of letters1. Dear Mr/Ms,Thank you for your letter No. A-3 of 6th May, offeringus 6 UI-4 Viewdatas. We have passed it on to ourTechnical Department for their c
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