There is a breakthrough in building aircrafts. Bendable wings covered with overlapping(部分重叠) pieces resembling fish sizes could be used to build swifter, fuel-efficient aircraft, a new study finds.

    Nowadays, conventional aircrafts typically rely on ailerons (副翼) to help control the way the planes tip as they fly. However, when the Wright brothers flew the first airplane, Flyer 1, over a century ago, they used no ailerons but wires and pulleys that twisted the wood-and-canvas wings, to control the plane.

    Scientists have long sought to develop aircrafts that can alter their wings during flight, just as birds can. However, most previous attempts have failed because they relied on heavy mechanical control structures within the wings. These structures were also complex and unreliable, said Neil Gershenfeld, a physicist and director of the Center for Bits and Atoms at Massachusetts Institute of Technology (MIT).

    The new wing consists of a system of tiny, strong, lightweight modules. The shape of the wing can be changed uniformly along its length using two small motors, which apply a twisting pressure to each wingtip. These wings are covered in “skins” of overlapping strips of flexible material resembling fish sizes. These strips move across each other as the wings alter, providing a smooth outer surface, the researchers explained.

    Wind-tunnel tests of these wings showed that they at least matched the aerodynamic properties of conventional wings, at about one-tenth the weight. Initial tests using remotely piloted aircrafts made with these wings have shown great promise, said Benjamin Jenett, a graduate student at the Center for Bits and Atoms at MIT.

    The new modular structures the scientists developed could be manufactured quickly in mass quantities and then installed by teams of small robots. These modular structures also can be disassembled more easily, making repairs simpler.

    “Still, the first aircraft built using this strategy will not be a passenger jet, ”Gershenfeld said. “Instead, the technology will likely first be tested on unmanned aircraft, leading to drones (无人机) that can fly for a long time, to help deliver internet access or medicine to remote villages and do some rescue works.”

    You may have heard of the American Dream, an ideal that has powered the hopes of Americans for generations.

    It began as a belief that the US was a land of opportunity, and that anyone could achieve success through hard work. The dream has referred to home ownership, a good job, retirement security or each generation doing better than the last for a long time.

    Yet today, this concept seems to have greatly changed. As Tune magazine pointed out, quite different from the older generation, many Millennials (the generation born after 1980) redefine the American Dream as “day-to-day control of your life”. They “prize job mobility, flexible schedules, any work that is more interesting than typing, and the ability to travel”, said the magazine.

    Home ownership, once the cornerstone of the American Dream, is becoming a smaller priority for this generation. Meanwhile, nearly 40% of them choose travel as part of their dream. And running their own business is a rising favorite, as nearly 26% of Millennials consider self-employment as part of their dream.

    So what has led to this huge change?

    Many point fingers at the poor economy. “Modern young Americans seem bound to face a world stamped by ever narrowing opportunity,” noted The Daily Beast.

    “The rate of 16-to-24-year-olds out of school and out of work is unusually high at 15%. Many college graduates have taken jobs that don't require a degree,” Time reported.

    The magazine worries that these difficulties may lead to a lost generation who are “unable to ever truly find their feet on the corporation's ladder”.

    Dan Kadlec, a reporter of Time, sees Millennials as resetting their expectations. “This situation is different for young adults today,” he wrote. “A true American dream has to feel attainable, and many Millennials are feeling they can only attain a day-to-day lifestyle that suits them.”

    French writer Frantz Fanon once said: "To speak a language is to take on a world, a culture." Since the world changes every day, so does our language.

    More than 300 new words and phrases have recently made it into the Oxford Dictionary Online, and in one way or another they are all reflections of today's changing world.

    After a year that was politically unstable, it's not hard to understand the fact that people's political views are one of the main drives of our expanding vocabulary. One example is "clicktivism", a compound of "click" and "activism". It refers to "armchair activists" -- people who support a political or social cause, but only show their support from behind a computer or smart phone.

    "We had all the words around Brexit (脱欧) in the last update and we are now starting to see all the words around Trump coming into the dictionary," Angus Stevenson, Oxford Dictionaries' head of content development, told The Guardian.

    Lifestyle is also changing our language. For example, "fitspiration -- a compound of fit and inspiration -- refers to a person or thing that encourages one to exercise and stay fit and healthy. The phrase "climate refugee" -- someone who is forced to leave their home due to climate change -- reflects people's concern for the environment.

    According to Stevenson, social media was the main source for the new expressions "People feel much freer to coin their own words these days." he said.

    But still, not all newly- invented words get the chance to make their way into a mainstream dictionary. If you want to create your own hit words, Angus Stevenson suggests that you should not only make sure that they are expressive and meaningful, but also have an attractive sound so that people will enjoy saying them out loud.

    Many people have long dreamed of being able to fly around as simply as riding a bicycle. Yet the safety and strength of a flying bike was always a big problem. Over the past 10 years, developments in technology have moved the dream of personal flying vehicles closer to reality. Now, two groups of inventors say such vehicles may be available soon.

    The British company Malloy Aeronautics has developed a prototype (原型) of its flying bicycle. Grant Stapleton, marketing sales director of Malloy Aeronautics, says the Hoverbike is able to get in and out of small spaces very quickly." It can be moved across continents very quickly because it can be folded and packed," he adds.

    Mr. Stapleton says safety was the company's main concern. He says the designers solved the safety issue by using overlapping rotors to power the vehicle.

    The company is testing a full-size prototype of the Hoverbike, which will most likely be used first by the police and emergency rescue teams.

    In New Zealand, Martin Aircraft Company is also testing a full-size prototype of its personal flying device, called the Jetpack. It can fly for more than 30 minutes, up to 1, 000meters high and reach a speed of 74 kilometers per hour.

    Peter Coker is the CEO of Martin Aircraft Company. He said the Jetpack "is built around safety from the start". In his words, “Reliability is the most important element of it. We have safety built into the actual structure itself, very similar to a Formula One racing car.

    The Jetpack uses a gasoline-powered engine that produces two powerful jet streams. Mr. Coker says it also has a parachute that would be used, if there should be an emergency. "It starts to work at very low altitude and actually saves both the aircraft and the pilot," he adds. Mr. Coker says the Jetpack will be ready for sale soon.

    Travis is the manager of G&G where he is responsible for forty employees (雇员)and profits (利润) of over $2 million per year. He's never late to work. He does not get upset on the job. When one of his employees started crying after a customer screamed at her, Travis took her away. "Your working uniform is your shelter," he told her. "Nothing anyone says will ever hurt you. You will always be as strong as you want to be."

    Travis picked up that lecture in one of his G&G training courses, an education program that began on his first day and continues throughout an employee's occupation. The training has, Travis says, changed his life. G&G has taught him how to live, how to focus, how to get to work on time, and how to master his emotions (情绪). Most importantly, it taught him willpower.

    At the center of that education is an extreme focus on an all-important habit; willpower. Dozens of cases show that willpower is the single most important habit for a person's success.

     And the best way to strengthen willpower is to make it into a habit. "Sometimes it looks like people with great self-control aren't working hard—but that's because they've made it automatic," Angela Duckworth, one of the University of Pennsylvania researchers said. "Their willpower occurs without them having to think about it."

     The company spent millions of dollars developing programs of study to train employees on self-control. Managers wrote workbooks that serve as guides to how to make willpower a habit in workers' lives. Those courses arc, in part, why G&G has grown from a sleepy company into a large one with more than seventeen thousand stores and profits of more than $10 billion a year.

    The surface of Venus（金星）has never seemed very hospitable. Temperatures change around 470℃（900℉）, the result of a runway greenhouse effect，and the pressure of its atmosphere, thick with carbon dioxide and sulfuric acid, is some 90 times that of Earth's. Lead（铅）would flow like water on Venus, and water cannot have existed in liquid form for perhaps a billion years.

    Now NASA'S Magellan spacecraft seems to have found one more horror in the nasty landscape: active volcanoes. Last week the space agency released the first detailed map of Venus and the most dramatic images ever made of its surface. The picture offer the best evidence to date that a planet once assumed dead is actually a lively pot of geological change.

    The most amazing image is of Venus's second tallest mountain, Maat Mons, which rises 8km（5 miles）. Most of the planet's many peaks, including 9.5-km-（6-mile-） high Maxwell Montes, look bright in the radar pictures Magellan takes from its orbit above the permanent could cover. That means they are strong reflectors of radar waves. But Maat Mons is dark; like the Stealth bomber, it absorbs much of the radar falling on it.

    This interesting fact, say project scientists, is a strong hint that the mountains has recently been covered with lava. Rock that sits on the surface of mountaintops appears to weather quickly in the hot，chemically reactive atmosphere, creating a soil that is rich in iron sulfide（硫化铁）• It is this mineral, the scientists believe, that can easily be seen on radar. If Maat Mons doesn't have any, it has probably been resurfaced, perhaps within the past few years.

    Such resurfacing has undoubtedly taken place in Venus lowlands: earlier images of the planet showed vast areas that are remarkably free of craters（火山坑）.That would be easy to explain on a Planet like Earth, where cratering from meteor strikes is erased by steady erosion. But while there is some evidence of wind erosion on Venus, the best explanation for the lack of cratering is periodic lava flow. Magellan has found direct evidence of such flows, including domelike upwellings and hardened streamed of rock trailing down the sides of Venusian peaks. There are also signs of other geologic activities, including dramatic faulting and several distinct incidents of mountain building. But the evidence can't indicate whether they really occurred millions of years ago. The case for active Venusian volcanoes is not yet proved, but Magellan, which is now well into its second complete survey of the planet's surface, may eventually settle the issue.