Reading comprehension: nano-paper

① Nano-paper is actually a broad concept, which refers to paper made of nano-materials or paper made by improving some properties of paper with nano-technology.

② "It will not be so easy to pierce a piece of paper in the future". This sentence refers to the recent emergence of high-strength and ultra-tough nano-paper. One common feature of these nano-papers is that they are extremely flexible. Although they are light, they have strength beyond steel.

③ In June 2008, Swiss scientists announced that they had successfully developed a kind of high-strength nano-paper. The inventor of this paper, Dr. berglund, said that this kind of nano-paper is extremely tough and hard, and it is made of cellulose, a biological material found in traditional paper. Mechanical tests show that the strength of this paper is 200 times higher than that of ordinary paper, reaching the level of current construction steel.

No, this is the highest strength nano-paper in the world at present. From June 5438 to 10, 2008, it was reported that researchers at Florida State University in the United States had developed a magical nano-paper. It looks like carbon paper, its specific gravity is110 of steel, but its strength is 500 times that of steel. This kind of paper is made of carbon molecules called "carbon nanotubes". The diameter of carbon nanotubes in this magical nano-paper is only a dozen nanometers, which is about one fiftieth of the diameter of human hair.

⑤ In addition to the cellulose and carbon nanotube paper mentioned above, in July 2007, the British magazine Nature also reported nano-paper made of graphite particles. This is also a kind of super paper that is harder than steel but extremely flexible. This new type of paper was successfully manufactured by a research group of Northwest University. The researchers dispersed carbon nano-film oxide particles in specially treated water and then filtered them with a filter membrane. They found that water can make particles form a paper-like thin layer on the surface of the filter; Nano-paper is stronger than paper made of carbon nanotubes and can be processed into various sizes. Unfortunately, however, this kind of nano-paper is afraid of water and will slowly decompose when soaked in water.

⑥ Because these nano-papers are light in weight, excellent in toughness and surprisingly high in strength, they will naturally have broad application prospects. Judging from the current technical development trend, bulletproof vests, spacesuits, and structural materials of automobiles, airplanes and spaceships will inevitably use this kind of nano-paper. (From Interesting Physics, No.6, 20 12)

1: Please talk about the magic of nano-paper in concise language. (3 points)

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2. Can the underlined word "positive" be deleted in paragraph ③? Why? (3 points)

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3. What explanation method is used in the underlined sentence in the fourth paragraph? What's the role? (3 points)

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4. Can the order of paragraphs ③-⑤ be reversed? Why? (3 points)

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Reference answer:

1.① light weight ② excellent toughness ③ surprisingly high strength.

2. It can't be removed. Zheng Zheng emphasized that the strength of this paper is many times higher than that of ordinary paper, and this effect cannot be achieved after removal.

3. Use the method of list and comparison. It accurately shows that nano-paper developed by researchers at Florida State University is the highest strength feature in the world at present.

4. They are not interchangeable, because each of the three sections introduces a kind of nano-paper, and the sections are arranged in the order of increasing strength.