题型:阅读理解 题类:模拟题 难易度:普通
北京师范大学附属中学2019届高三英语高考信息卷(四)
We can video chat with astronauts aboard the International Space Station and watch live footage from the frozen heights of Everest. But communicating with a submarine (潜艇)or a diver is not so easy. The lack of practical methods for sharing data between underwater and airborne devices has long been a frustration for scientists. The difficulty stems from the fact that radio signals work perfectly in air travel but poorly in water. Sonar (声呐)signals used by underwater sensors reflect off the surface of the water rather than reaching the air.
Now, researchers at MIT have developed a method with the potential to revolutionize underwater communication. "What we've shown is that it's actually feasible to communicate from underwater to the air," says Fadel Adib, a professor at MJT's Media Lab, who led the research.
The MIT researchers designed a system that uses an underwater machine to send sonar signals to the surface, making vibrations (震动)corresponding to the ls and Os of the data. A surface receiver then reads and decodes these tiny vibrations. The researchers call the system TARF. It has any number of potential real-world uses, Adib says. It could be used to find downed planes underwater by reading signals from sonar devices in a plane's black box and it could allow submarines to communicate with the surface.
Right now the technology is low-resolution. The initial study was conducted in the MIT swimming pool at maximum depths of around 11 or 12 feet. The next steps for the researchers are to see if TARF is workable at much greater depths and under varying conditions—high waves, storms, schools of fish. They also want to see if they can make the technology work in the other direction— air to water.
If the technology proves successful in real-world conditions, expect "texting while diving" to be the latest underwater fashion.
Here are opportunities for international student volunteers. You can apply your academic training to overall development programs in service. Group service options are explained here.
Elder assistance Assist at the elder care center with activities such as playing cards and swapping stories. And you can join the elders on day-trips to the local museums, parks and grocery stores. Or, help prepare, serve and deliver meals at the assisted living center on the reservation. Blackfeet Reservation Montana September 15—September 21 |
Early Childhood Education Inspire children 1 to 5 years old through doing arts and crafts, reading storybooks, playing with toys, teaching hand washing with soap and water, and more. As a volunteer in the Cook Islands, you make contributions to the future through the youngest of citizens. Rarotonga Cook Islands August 17—August 24 |
Health Care Health care volunteers are needed at the clinic, serving all of the 1,300 children of the community. To help specialists, volunteers can be engaged to help sort medicines, make cotton balls and take children's temperature, etc. Health Care volunteers do not need any special permit or license. Lima September 3—September 24 |
Teach English Started in 1996, the program is to teach English in China and build a bridge of friendship and respect. Here you teach English lessons to secondary or university students with all levels of language abilities. After school, you can join your students in a number of cultural activities to extend the day's English lessons. Xi'an August 22—August 28 |
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