【英语时差8,16】为什么特氟隆很滑
时间：2019-01-22 作者：英语课 分类：英语时差8，16
Why Teflon Is Slippery Teflon is the trademark 1 name for PTFE, a type of plastic. If you own any non stick cookware, then you probably use PTFE on a daily basis. You might not realize, as you fry your morning eggs, that PTFE is one of the most slippery materials that can be manufactured. It’s about as slippery as wet ice. Teflon is chemically similar to another, more common plastic: polyethylene, the material used to make plastic bags and other plastic containers. Chemically, polyethylene is made from long chains of carbon atoms with hydrogen atoms bonded 2 to the sides of the chains. To make Teflon, the hydrogen atoms of polyethylene are replaced by fluorine atoms. It’s the fluorine atoms that give Teflon its slipperiness. Fluorine atoms are physically 3 bigger than hydrogen atoms. Their large size makes them huddle 4 around the central carbon chains in a much tighter formation. This tight formation works like a kind of chemical armor, protecting the carbon atoms which in turn hold the molecule 5 together. This chemical teamwork between carbon and fluorine makes Teflon extremely chemically stable, and it’s this chemical stability that makes Teflon so slippery. Foreign substances, like a frying egg, can find no chemical foothold on the fluorine armor, so they simply slide away. Getting this slippery substance to stick to a frying pan is a bit of a trick. Teflon is broken into a fine powder and suspended in water. The pan is then thoroughly 6 cleaned, then roughened by sand-blasting. The Teflon is sprayed onto the pan and baked, causing it to fuse together and lock onto the roughened surface of the pan. As long as you don’t scratch this protective coating, years worth of fried eggs, melted cheese, burned milk even toffee will slide away effortlessly.
- The trademark is registered on the book of the Patent Office.该商标已在专利局登记注册。
- The trademark of the pen was changed.这钢笔的商标改了。
- The whisky was taken to bonded warehouses at Port Dundee.威士忌酒已送到邓迪港的保稅仓库。
- This adhesive must be applied to both surfaces which are to be bonded together.要粘接的两个面都必须涂上这种黏合剂。
- He was out of sorts physically,as well as disordered mentally.他浑身不舒服，心绪也很乱。
- Every time I think about it I feel physically sick.一想起那件事我就感到极恶心。
- They like living in a huddle.他们喜欢杂居在一起。
- The cold wind made the boy huddle inside his coat.寒风使这个男孩卷缩在他的外衣里。
- A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
- This gives us the structural formula of the molecule.这种方式给出了分子的结构式。
- The soil must be thoroughly turned over before planting.一定要先把土地深翻一遍再下种。
- The soldiers have been thoroughly instructed in the care of their weapons.士兵们都系统地接受过保护武器的训练。