VOA常速英语2015--新技术降低废金属分离成本

Scrap-Metal Separation May Become Cheaper 新技术降低废金属分离成本 According to the Environmental Protection Agency, the United States throws 14.8 million tons of scrap metal into landfills every year. One of the main reasons is the diffi

考研背诵50篇——36.Plate Tectonics and Sea-floor Spreading

The theory of plate tectonics describes the motions of the lithosphere, the comparatively rigid outer layer of the Earth that includes all the crust and part of the underlying mantle. The lithosphere(n.[ 地 ] 岩石圈 )is divided into a few dozen p

VOA常速英语2016--全息图或可与CT及超生扫描仪兼容

全息图或可与CT及超生扫描仪兼容 Since the 1980s, doctors have used Magnetic Resonance Imaging machines, or MRI scanners, to look into patients bodies without exposing them to the harmful effects of X-rays.An alternating magnetic field cr

VOA标准英语2015--马里兰大学实验室复刻地球磁场

Scientists Take on Earths Magnetic Field 马里兰大学实验室复刻地球磁场 WASHINGTON Most of us hardly ever think about the Earth's magnetic field. We might be aware that it helps guide birds as they migrate and ensures that our compasses p

科学美国人60秒 SSS 2014-09-15

Sepsis is a potentially deadly inflammatory condition caused by infections. Muppet creator Jim Henson was a famous victim. Proper treatment of sepsis can require knowing what bacteria or virus caused the infection. But the identification can take day

[科学美国人60秒] SSS 2015-10-13

If you are lost, you need a map and a compass. The map pinpoints where you are and the compass orients you in the right direction. Migratory birds, on the other hand, can traverseentire hemispheres and end up just a couple of miles from where they br

英语听力：自然百科 地球力场 Earth's Force Field—1

The solar system is a hostile place. Earth is under attack from deadly cosmic radiation. Life here is only possible, because it's protected by the magnetosphere, an invisible force field that cocoons the planet. But new evidence reveals that this vit

英语听力：自然百科 地球力场 Earth's Force Field—2

Radiation causes damage at the most fundamental level. It mutates the blueprint of life, DNA. Earth's magnetosphere is our crucial defense. It's so fundamental to our evolution and continued existence that the race is on to understand why it's changi

英语听力：自然百科 地球力场 Earth's Force Field—18

Earth's magnetic field has reversed thousands of times since its formation 4.5 billion years ago. And scientists now believe that the next reversal is imminent. The race is on to predicting exactly when it will occur. In 2010, the European Space Agen

英语听力：自然百科 地球力场 Earth's Force Field—19

As the reversal approaches, the decay of our magnetic field will continue and cosmic radiation will get increasingly close to the Earth's surface. As the reversal approaches, the decay of our magnetic field will continue and cosmic radiation will get

英语听力：自然百科 地球力场 Earth's Force Field—13

Glatsmire's model shows that the magnetic poles swap places spontaneously due to / complex processes within the core. We were used to the idea that a compass points somewhere near the North Pole and hence we can use it for navigation, but there are p

英语听力：自然百科 地球力场 Earth's Force Field—15

By analyzing thousands of lava samples, geophysicists discover/ that the Earth's magnetic field has reversed over 18,000 times in the last 20 million years. On either side of these reversals is a long period of dramatically reduced field strength. Du

英语听力：自然百科 地球力场 Earth's Force Field—17

We drive them about 20 miles away to the North, and release them, and we track them as they try to fly back home. We drive them about 20 miles away to the North, and release them, and we track them as they try to fly back home. Hes up, OK. Holland wa

英语听力：自然百科 地球力场 Earth's Force Field—14

By analyzing different samples of lava, Herrero / Bervera has built up a picture of how the filed has changed since long before humans were around. They are actually the recorders of the Earth's magnetic field in hundreds of years, thousands of years

英语听力：自然百科 地球力场 Earth's Force Field—3

In polar regions where the magnetic field is / weakest, auroras glow in the sky. These dazzling displays of colored lights form when solar particles slam into gases in our atmosphere causing them to glow. The stronger the solar wind, the more dramati

英语听力：自然百科 地球力场 Earth's Force Field—6

It's clear from the fact that the Martian crust is strongly magnetized, that there must have been a magnetic field on Mars in the past, that the only way we know to magnetize rocks is for them to form in the presence of magnetic field. Why did Mars l

英语听力：自然百科 地球力场 Earth's Force Field—7

The loss of the magnetic field has a catastrophic impact on the planet's evolution. Mars becomes the red planet we see today. If earths magnetic protection continues to fade, would it suffer the same fate? If it vanishes completely, the planet might

英语听力：自然百科 地球力场 Earth's Force Field—11

Blockson's computer model reveals that at the South Atlantic Anomaly, the magnetic field isn't just weaker than anywhere else on the planet. It's actually reversed polarity. There is a patch on the core in the South Atlantic where things are not poin

英语听力：自然百科 行星旅行指南：木星 Jupiter—13

Gas escaping into space from the plumes is energized by Jupiters magnetosphere, creating an intense band of ionizing radiation that bombards a surface already soaked in emissions. If you went out relatively unprotected with, like a normal spacesuit f

【简明语法】15.1 并列结构作主语时谓语用复数

Reading and writing are very important. 注意： 当主语由and连结时，如果它表示一个单一的概念，即指同一人或同一物时，谓语动词用单数，and 此时连接的两个词前