1 . Someday, you may no longer need to brush your teeth by hand. Instead, a group of billions of nanoparticles (纳米粒子) could automatically do it for you. It would be especially life-changing for those who find it difficult or impossible to hold and move a toothbrush.
Steager, an engineer at the University of Pennsylvania in Philadelphia and Hyun Koo, an inventor and dental researcher there, found a way to form the nanoparticles into long, skinny bristles (刷毛), a lot like the ones on a toothbrush. But these bristles shape-shift to fit whatever surface they encounter.
The tooth-cleaning robot works due to two magnets (磁铁). One goes each side of the teeth. The nanoparticles sit in a liquid between the magnets. When the magnets are turned off, the nanoparticles move randomly in the liquid. As soon as one magnet gets turned on, the nanoparticles gather together near its center. When the researchers turn on the other magnet and turn off the first one, the nanoparticles extend outward in long, skinny bristles. When there’s a tooth in the way, these bristles can’t stretch out as far as they want. So they push against the tooth’s surface. If there’s a gap between teeth, they push into the gap. Moving the magnets makes the bristles move against and between teeth. All that motion cleans the teeth. As a bonus, the nanoparticles also have strong power to kill viruses.
The new device is just a proof of concept. The researchers still need to turn it into a product that people will want to use. “There’s a lot of engineering to get from here to there, but every good idea needs to have a start.” says Steager.
1. What is special about the tooth cleaner?| A．It’s transformable. | B．It’s water-proof. |
| C．It contains skinny bristles. | D．It looks like a toothbrush. |
| A．The working principle. | B．The magnets’ motion. |
| C．The virus-killing process. | D．The bristles’ formation. |
| A．Uncertain. |
| B．Concerned. |
| C．Confident. |
| D．Shocked. |
| A．A Tooth-Cleaner Fighting Bacteria | B．A New Concept for a New Start |
| C．A Breakthrough in Medicine | D．A Shape-Shifting Robotic Tooth-Gleaner |
2 . Many people believe that working to the maximum is the secret to success, but research has found that moderation(适度) also gets results on the job.
In a study led by Ellen Langer of Harvard University, researchers asked people to translate sentences into a new made-up language. Subjects who practiced the language moderately beforehand made fewer errors than those who practiced extensively or not at all. High levels of knowledge can make people too attached to traditional ways of viewing problems across fields the arts, sciences, and politics. High conscientiousness is related to lower job performance, especially in simple jobs where it doesn’t pay to be a perfectionist.
How long we stay on the clock and how we spend that time are under careful examination in many workplaces. The young banker who eats lunch at his desk is probably seen as a go-getter, while his colleagues who chat over a relaxed conference-room meal get dirty looks from the corner office. “People from cultures that value relationships more than ours does are shocked by the thought of eating alone in front of a computer”, says Art Markman, a professor of psychology at the University of Texas, Austin. Social interaction has been shown to lift mood(情绪) and get people thinking in new directions and in ways that could help improve any post-lunch effort.
Markman also promotes off-task time. “Part of being a good thinker is experiencing things that are seemingly unrelated to what you are working on at the moment but give you fresh ideas about your work,” he says. “Also, there is a lot of research showing that a positive mood leads to higher levels of productivity and creativity. So, when people do things to increase their life satisfaction, they also make themselves more effective at work.”
1. What does Ellen Langer’s study show?| A．It is worthwhile to be a perfectionist | B．Translation makes people knowledgeable. |
| C．Simpler jobs require greater caution. | D．Moderate effort produces the best result. |
| A．is good at handling pressure | B．works hard to become successful |
| C．a has a natural talent for his job. | D．gets on well with his co-workers |
| A．A good thinker is able to inspire other people. |
| B．Experience unrelated to your job is useless. |
| C．A cheerful mood helps make a creative mind. |
| D．Focusing on what you do raises productivity. |
| A．Middle-of-the-road work habits. | B．Balance between work and family. |
| C．Long-standing cultural traditions. | D．Harmony in the work environment. |
