When it comes to long-distance space travel, the biggest problem is that spaceships can only get as far as the fuel onboard allows. In 1964, a British writer Clarke came up with the idea of "solar sailing "in his science fiction. He wrote of large, mirror-like sails that collect power from the sun and free spaceships from the limitation of fuel.
This sci-fi idea was first successfully brought to reality (现实)in 2010 by Japan's IKAROS satellite. Ever since then, the technology has improved mission by mission, with the latest being NASA's Advanced Composite Solar Sail 3 (ACS3).NASA has recently announced that it's going to team up with Lithuania's satellite-building company NanoAvionics to test its new sail in low-Earth orbit.
To many, a solar sail (太阳帆) may look like a giant solar panel (太阳能电池板), but it actual works very differently. While solar panels take in energy from the sun and change it into power solar sails use photons(光子) given off by the sun to create direct power. Besides, solar panels are big and heavy to carry, while solar sails are just the opposite.
According to Abbott, the CEO of NanoAvionics, the upcoming low-Earth orbit trial with NASA, if successful, will be followed with deep-space missions that involve larger solar sails. These are ideal for low-cost and long-distance space travel because fuel will no longer be a problem.
"It started as a sci-fi dream, "Popular Mechanics reporter Jennifer Leman wrote. "Now it could be the future of space flight."
Wearing a white blouse, Ai-Da studies her subject and begins to draw. She looks like any artist at work. However, the "beep ... beep ... beep" noise from her arm gives her away. Ai-Da is, in fact, a robot.
Ai-Da has been described as the world's "first Al (人工智能) robot artist". She takes her name from Ada Lovelace, the world's first female computer programmer. Scientists at Oxford University developed Al systems (系统) for Ai-Da. The robot has cameras in her eyeballs. After she has studied a subject, she will use her left arm to draw. Now, Ai-Da can only use a pencil for sketches (素描).The plan is for her to paint.
Ai-Da is not the first Al system to produce artworks. Since 2006, scientists have been developing software (软件) to turn photos into drawings. Last year, an artwork created using Al was sold in New York for$432,500. However, Ai-Da's human-like appearance." brings something new to the field.
In June, Ai-Da opened her first exhibition at Oxford. Then were about 30 drawings by the robot. Ai-Da, standing next to her artworks, attracted (吸引) many visitors.
Ai-Da's inventor, Aidan Meller, talked about the importance of the robot. "Ai-Da bring a new voice to the art world," she said "Al is going to be the big thing of the 2020s. That influences us greatly." Meller hopes the exhibition was just the start and that more will follow to show how AI is influencing human life.
"Miss Smith! What rough (粗糙的) hands Mary Jessup has! "said Daisy Marvin, as she walked home from school with her teacher.
"In my opinion, Daisy, Mary's hands are the prettiest in our class"
"Why? Miss Smith, they are as red and hard as they can be. How they would look if she tried to play on a piano! "Daisy said.
Miss Smith took Daisy's hands in hers, and said, "Your hands are very soft and white, just the hands to look beautiful on a piano; yet they don't have one beauty that Mary's hands do .Shall I tell you what the difference is?”
"Yes, please, Miss Smith." Daisy looked at Miss Smith, with eyes wide open.
"Will, Daisy, Mary's hands are very busy. They wash dishes; they make fires; they hang out clothes, and help to wash them, too; they are always trying to help her poor, hard-working mother."
Miss Smith continued, "Besides, they wash and dress the children; they mend their toys and dress their dolls; yet, they find time to bathe the head of the little girl who is so sick in the next house to theirs."
"They do good deeds (行为) to every living thing. I have seen them patting the tired horse and the homeless dog in the street. They are always ready to help those who need help."
"I shall never think Mary's hands are ugly any more, Miss Smith." Daisy said that with tears in eyes.
"I am glad to hear you say that, Daisy; and I must tell you that they are beautiful because they help others gladly and cheerfully."
"Oh, Miss Smith! I feel so ashamed of myself and so sorry, "said Daisy, looking into her teacher's face with shining eyes.
“My dear, beauty doesn't lie in how one looks but what he does."
People say laughter is the best medicine, but sometimes too much of a good thing may not be so good. What happened to me last night made me deeply understand the meaning of that.
Last night I was alone at home. When I was watching a funny movie, I suddenly started laughing and couldn't stop myself.
At first, I was feeling good.
But after about 5 minutes, I came to know I wasn't going to stop at all. I began to feel a little worried.
Time for bed. But I couldn't sleep because I kept laughing. So I got up and started doing some housework. I cleaned my apartment, laughing hard. I washed all the dishes left over from dinner, still laughing crazily. I tried to hold my cat in my arms, but it ran away from me in fear. I spent the rest of the night in front of my computer, of course, still laughing.
When time finally came to get ready for work, I realized that I simply couldn't go to the office like that. I decided to call my boss for leave, but laughing was the only thing I could do on the phone.
After listening to my "lovely" laughter for a few minutes, my boss couldn't help shouting angrily, "Are you mad? You're fired (解雇 ) !"
Suddenly I woke up. Thank God! I just had a dream.
Do you know a saying about the swan feather (天鹅羽毛)?
This saying comes from a historic book called Lu Shi. According to the story, a Tang Dynasty official (唐朝官员) in Yunnan wanted to show his respect to the emperor. He sent a man named
Mian Bogao to bring some gifts to the emperor. One of the gifts was a beautiful swan, and it was a very valuable gift at the time.
Mian took good care of the swan on his way to the emperor. One day he passed by a lake and wanted to let the swan drink some water. But as soon as he set the swan free, the swan flew away, leaving only some feathers on the ground. Mian was very worried, but he didn't run away. He decided to tell the emperor what happened. He picked up a feather and kept going on his trip.
When Mian met the emperor, he told him what happened and said, "This swan feather is light, but it carries my deep respect for you. "The emperor was happy with Mian's honesty and sincerity (真诚). He forgave Mian. People now use the saying to show that a good gift doesn't have to be expensive. What matters is the sincerity it carries.
Whether from news reports or social media articles, you may know that 5G is coming.
5G is the 5th generation network. It is a new network (网络) after 1G, 2G, 3G and 4G and it can connect everyone and everything together. 5G networks will cover/many cities in China soon. 5G means super-fast data (数据) speed, One can download a two-hour movie for fewer than 10 seconds, and it is making our hives more and more convenient.
5G will make self-driving cars possible. For safety, self-driving cars need super-fast data transmission (传输) to communicate with their nearby environment. 5G is just what makes self-driving cars achieve this, even airplanes will become "smart" in the near future. Passengers will be able to use 5G networks in the air to connect to the Internet or place orders for food and drinks.
5G will be a big help for students who take online classes. Many people live in poor areas in the world where there are no schools. But with 5G, this will change. Students all over the world will be able to see places like the Great Wall without leaving their rooms.
It will be also easier for doctors to treat patients remotely by 5G. It means caring for patients from far away.
The fats listed above are only a part of what 5G will make possible and popular. Just as in the early days of the Internet in the 1990s, few could see how it could change or lie and the world. The same will surely be true of 5G. With 5G, many things do not seem like dreams anymore. Now let's get ready to say goodbye to 4G and welcome the coming of 5G.
The opening of the Beijing-Zhangjiakou high-speed railway took place in December, 2019. The railway is a milestone in China's railway development because it has used the latest technologies in railway building.
The railway is 174 kilometers long, with 10 stations. The stations are managed by one control center, which is described by China Railway Beijing Group－also known as CR Beijing－as an "intelligent brain". The center collects and shares the stations' real-time information. "With the information, the workers in the center can control the stations' lighting and temperature, monitor (监测) trains' operation and deal with emergencies (紧急情况)," said Zhu Dianping, from CR Beijing.
Zhu said some trains on the Beijing-Zhangjiakou line are "smart" as they provide 5G signals and wireless charging (无线充电) for passengers, as well as intelligent lighting. These trains can start and stop, open and close doors, and deal with emergencies themselves.
All the ten stations provide e-ticket services. Travelers who have bought tickets online can use their ID cards instead of waiting in line for paper tickets.
At Qinghe Railway Station in Beijing, China's first visual remote ticket vending machine (远程可视售票机) has been installed (安装) to help passengers who are not able to afford tickets online. Passengers keep in touch with the conductor through the machine and buy tickets according to video instructions.
In addition, the Badaling Great Wall Station, the deepest underground railway station in China, is another great example of the country's achievements in railway building.
It's a common belief that fish can't remember anything for longer than seven seconds. It may seem sad to think that every moment in their lives would be like seeing the world for the first time. But don't be so quick to feel sorry for them. A new study has found that fish have much better memories than we used to think.
In the study, researchers from Mac Ewan University in Canada trained a kind of fish called African cichlids to go to a certain area of their tank to get food. They took the fish out and then waited for 12 days before putting them back in the tank again. They found that after such a long break the fish sill went to the same place where they first got food.
In fact, scientists had been thinking for a long time that African cichlids might have a good memory. But there was no clear evidence until the latest findings.
Just as a good memory can make our lives easier, it also plays an important part when a fish is trying to survive in the wild. "If fish are able to remember that a certain area contains (容纳) safe food, they will be able to go back to that area without putting their lives in danger," lead researcher Trevor Hamilton told Live Science.
So next time you are watching your pet fish from outside the tank, perhaps you should feel close to them-they may remember who you are.
Part of Earth's beauty comes from its oceans. Ocean scientists study the chemical make-up of the ocean, weather patterns, the geography of the ocean floor, and many other areas. Their work is exciting, although sometimes dangerous. Using technology to do certain tasks helps. For example, robotic arms are used for very dangerous tasks.
One basic part of ocean study is understanding waves and how they work. Wind is the great maker of waves. The waves we know are mostly produced by winds blowing over the sea. They are directly connected with the wind speed and the time that wind lasts.
Sometimes ocean life can be seen in the wave. Living things seem to be staying within the wave, moving slowly inside it as if they were weightless. Besides the beauty of waves, scientists are interested in their technical ways. The diagram of waves shows how scientists examine waves. Waves are measured (测量) from the top (crest) to the bottom (trough). This allows scientists to find out the height of a wave. They also measure waves from crest to crest to determine (测定) the length of a wave.
During serious storms, huge waves migh cut a sea ship apart. Ships are at great risk of winding up as broken pieces after being hit by the force of a huge wave. By understanding the ocean, scientists can prevent this breakup of ships by predicting when the water will be too dangerous for people and their ships. The study of waves and the ocean also allows scientists to make sure how certain beaches were formed. By studying the oceans, a great deal can be learned about the surface we live on.
①Scientists can decide the weather patterns.
②We can't find living things in the waves.
③By studying the ocean, scientists can prevent the breakup of ships.
④The study of waves helps scientists know how certain beaches were formed.
A horse fair is an interesting place. There were young horses from the country, little Welsh ponies and many beautiful horses too. But there were also a lot of poor, thin horses, tired from hard work. I was very sad to see them.
At the horse fair there was a man with a gentle voice and kind grey eyes. He offered 23 pounds for me, but they refused. Then a man with a very loud voice came. I was afraid he was going to buy me, but he walked off. Then the grey-eyed man came back again and said:
"I'll give 24 for him."
"Done," said the salesman. "He's a quality horse and if you want him for cab (出租马车) work, he's a bargain."
Half an hour later we set off for London, along country roads, until we came to that great city. There were streets to the right, and streets to the left. We went into one of the small streets, and then into a very narrow street, with small, old houses.
My owner stopped at a house. The door opened, and a woman, a little girl and boy, came out.
"Is he gentle, father?"
"Yes, Dolly, as gentle as a kitten; you can pat him."
Dolly, the little girl, patted my shoulder without fear. It felt so good! They led me into a comfortable, clean stable, and after a delicious meal I lay down to sleep, thinking "I'm going to very happy here".
My new owner's name was Jerry. His wife was called Polly and they had two children, Harry and Dolly. The next morning they came to see me. I loved it when they patted me and spoke in gentle voices.
"Let's call him 'Jack', after the old horse, shall we, Harry?" said Dolly.
"Yes, let's," said Harry.
The first week of my life as Jack, the London cab horse was very hard. The noise and the people and the traffic on the streets scared me. But Jerry was a very good driver, and that helped a lot Jerry soon found that I was ready to work hard and do my best, and he didn't whip (鞭打) me.
He kept us very clean, and gave us as much food as we wanted. But the best thing was that we had Sundays off.
