When a laptop or smartphone battery starts losing its power, the only options are to buy an expensive replacement, or just keep it plugged in all the time. But a woman Mya Le Thai may have found the answer to this problem.
Thai was frustrated that the batteries for her wireless devices degraded(降级)over time, until they failed to charge fully. She did not like having to keep her laptop connected to an electrical outlet to keep it powered on. So, she decided to do something about that problem. At first, she and her team at UC Irvine thought about inventing a new battery. But as they experimented, Thai discovered something that might permit lithium—ion(锂离子)batteries to last forever.
Lithium-ion batteries power most wireless devices. Over time, the batteries lose the ability to hold a charge. Most of these batteries have a life span of about 7,000 charging cycles before they die. One of the reasons lithium—ion batteries degrade is their use of nanowires to carry electricity. Nanowires are extremely thin. A human hair is thousands of times thicker, for example. Nanowires are extremely efficient carriers of electricity, which makes them useful in batteries.
But, Thai had a theory—the nanowires might last longer if covered with a gel(凝胶). She and her team tested this theory. "It was a long process and a lot of work, "Thai said. The team tried many coverings for the wires. PMMA, a type of plastic, was one of them. The nanowires were coated with PMMA and cycled through charges 200, 000 times. The PMMA-coated nanowires showed no evidence of damage. The results suggest that batteries could last forever, without losing charging ability.
Thai hopes to continue her research to understand why this gel works so well and to see if any other gel could create better results and she is enjoying the publicity about her discovery. She said she never expected her research to get media coverage. "It's kind of cool," she said. "I'm really glad people are showing interest in my work and not just in the work itself, but also in technology and energy."
Sound is very important in our daily lives. Most of us get information and know what's happening around us by the sounds we hear. We talk with other people and listen to radio and television broadcasts for music, news, and enjoyment.
Sound can be useful and pleasing or it can be unpleasant, and damaging to our ears. Unwanted, harmful sounds are called noise pollution.
The movements of people, animals, machines, and other things cause pressure waves in the air. If these pressure waves are within a certain range(范围)of frequencies(频率), our ears believe that it is sound. Sound waves are like the waves in a lake when you throw a stone. The bigger the stone, the bigger the waves. And that's how sound works. Big sounds cause larger waves.
Scientists measure these sound waves in decibels. To be heard by humans, a sound wave must measure at least ten decibels. When these waves reach a high number of decibels, our ears start to hurt and damage can occur. If you've been around loud noises for several hours, you may have experienced damage. It's important to know the danger signal: ringing in your ears.
Keep your ears safe-be careful what you hear!
You've heard of the fat suit and the pregnancy suit; now meet AGNES—the old person suit.
AGNES stands for “Age Gain Now Empathy(换位体验)System” and was designed by researchers at MIT's AgeLab to let you know what it feels like—physically—to be 75 years old. “The business of old age demands new tools,” said Joseph Coughlin, director of the AgeLab. “While focus groups and observations and surveys can help you understand what the older consumer needs and wants, young marketers never get that Ah ha! moment of having difficulty opening a jar, or getting in and out of a car. That's what AGNES provides. ”
Coughlin and his team carefully adjusted the suit to make the wearer just as uncomfortable as an old person who has spent a lifetime eating poorly and not doing much exercise. Special shoes provide a feeling of imbalance, while braces on the knees and elbows limit joint mobility. Gloves give the feeling of decreased strength and mobility in the hands and wrists, and earplugs make it difficult to hear high—pitched sounds and soft tones. A helmet with straps(带)attached to it presses the spine(脊柱), and more straps attached to the shoes decrease hamstring flexibility, and shortens the wearer's step.
AGNES has been used most recently by a group of students working on a design of an updated walker. By wearing the suit they could see for themselves what design and materials would make the most sense for a physically limited older person. Coughlin said the suit has also been used by clothing companies, car companies and retail goods companies to help them understand the limitations of an older consumer.
“AGNES is not the destiny of everybody,” he said. “She is a badly behaved lady who didn't eat and exercise very well. A secondary benefit we've found with AGNES is that it has become a powerful tool to get younger people to invest in their long-term health. ”
As China is playing an increasingly important role on the world stage, Chinese is also becoming the language to be learned (global) in the new century. China stands to become the pioneer of the world's economy in the near future due to the rapid economic ( grow ) as well as the world's largest population, which will make learning Chinese very significant either for people from all walks of life for those who wish to visit China.
For native English speakers, However, Chinese is a very different language, vocabulary is wholly unfamiliar and unlike anything we know. In addition, in the Chinese tone system, words (speak) in rising or falling tones, which help to distinguish them. What usually (cause) beginners confused most is that a collection of thousands of individual ideograms (表意文字) ( represent ) a word or an idea have no phonetic value-that is to say, we can't tell how the word is pronounced how it is written. There is a method of presenting written Chinese in a phonetic script called pinyin and working with this pinyin system is the first thing for foreign learners. All these (factor) make learning Chinese difficult for us. Yet, for a determined learner, there's always a way (overcome) the difficulties.
Children learn to construct language from those around them. Until about the age of three, children tend to learn to develop their language by modeling the speech of their parents, but from that time on, peers have a growing influence as models for language development in children. It is easy to observe that, when adults and old children interact with younger children, they tend to change their language to improve communication with younger children, and this changed language is called caretaker speech
When speaking to young children most people will, without thinking, find ways to simplify their language. A caretaker will speak in one way with adults and in a very different way with young children. Caretaker speech tends to be slower speech with short simple words which are said in a high-pitched (高嗓音)voice with strong inflections (音调变化) and many repetitions of essential information.
Caretaker speech serves the very important function of allowing young children to acquire (学得) language more easily. The simplified words and sentences make it easier for the small child to begin to comprehend, and the repetitions strengthen the child's developing understanding. Then, as a child's speech develops, caretakers tend to adjust their language to a level that is slightly above that of a younger child. Without recognition of what they are doing, these caretakers will speak in one way to a one-year-old and in a more complex (复杂的) way as the child reaches the age of two or three.
There are debates among experts about whether caretaker speech is a natural function or a learned one. Those who believe that caretaker speech is a natural function in humans believe that it is human nature for children to acquire language and for those around them to encourage children to learn language naturally; the presence of a child is itself a natural stimulus (刺激) that increases the rate of caretaker speech among those present.
However, other experts believe that caretaker speech develops through nurturing (教育) rather than nature. They argue that people will try out different ways to communicate with a child and according to the child's responses, choose the most effective speech; a parent might, for example, learn to use speech with strong inflections with a small child because the strong inflections do a better job attracting the child's attention than do more small inflections.
Children art education is something that is much encouraged for the child's creative growth. This is necessary because a child can have a sense of appreciation of the arts and along with all the other things that they learn in school.
Children art education should be designed from a very early age so that they are allowed to express themselves freely in whatever way that they wish to.
However, the task of children art education is not a very easy one, because you have to find the right way in which you can help them get interested in what you are trying to teach them.The physical space where the art education is to be carried out should also be carefully decorated to make it attractive to the children. Use of colors should be made in abundance (丰富) as that is what attracts a child first to it.
Displaying examples of artwork that you think would be important enough to influence the children is also a good idea. Of course, a photograph of a painting of the Madonna (圣母马利亚) is something that children might not appreciate.This will be a source of inspiration for the children to try them out as well.
The creative process is something that you must not interfere with (干涉) during a children art education class.But after that, you must wait for the children themselves to come up with something meaningful to their ability. As long as the end result is connected with the topic, every child's art work is worth praising.
A. You can just give them a topic for drawing.
B. A trip to an art museum can be an inspiration to many students.
C. They also have a place where they can express all their feelings.
D. The reason for this could be the lack of interest in the teacher.
E. This is the only way that art can be appreciated as children grow up.
F. So creating the right environment for children art education is very important.
G. Instead, put up paintings that children will be fond of.
增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。
删除：把多余的词用斜钱（\）划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1）每处错误及其修改均仅限一词；
2）只允许修改10处，多者（从第11处起）不计分。
Disappointed at the result of the examination, I sat in the sofa in silent after school. My father found I was so unhappy but came to ask me why. After learning the reason, my father give me a smile. He said, "Don't allow the terribly things in your life to discount the positive one. Don't let a bad day or month or year to make you feel like you have a bad life. Instead focusing on everything that's going wrong, start holding onto all of the things that is going right. You'll feel better soon." Hear what my father said, I felt it the shame to act like that and decided to cheer myself up.
1）读书的好处；
2）发出倡议。
注意：
1）词数80左右；
2）可适当增加细节，以使行文连贯。
Dear boys and girls,
Students' Union
