结构组合件

This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute. Airplane manufacturers have been changing over from aluminum to advanced composite materials. These lighter, stronger composites are made of fibers of

发表于:2018-12-24 / 阅读(44) / 评论(0) 分类 Scientific American(三)月

A report in the journal Science announces the finding of the oldest known human-fashioned threads, left in a cave by the Caucasus mountains about 34,000 years ago. Cynthia Graber reports. We humans love to decorate things. We wear flashy clothes, ti

发表于:2019-01-02 / 阅读(93) / 评论(0) 分类 60秒科学

肌肉生而不等 Don:Its not fair! Yal: Whats not fair? D: I was rereading the Constitution of the United States. It says here that All people are created equal.Thats just not true! Y:What do you mean? D: Well, its always being my dream to become t

发表于:2019-02-16 / 阅读(42) / 评论(0) 分类 英语听力文摘 English Digest

The Color of Lint 绒线的颜色 You go to the local laundromat to do your wash.In the spinning barrel full of sudsy water you load clothes of all colors: a bright red tee-shirt, blue jeans, a green bandanna. The original mix of clothing is as multi

发表于:2019-02-24 / 阅读(30) / 评论(0) 分类 英语听力文摘 English Digest

The Parts of Metabolism 新陈代谢到底是什么? What is metabolism really? Statements like he can eat a lot because he has a fast metabolism are somewhat misleading. Metabolism isnt about the digestion of food in your stomach; its the name giv

发表于:2019-02-24 / 阅读(61) / 评论(0) 分类 英语听力文摘 English Digest

Hey! and thenOuch! 伤害性刺激作用于末梢神经引起神经兴奋电活动,沿着脊髓传人神经纤维中的细纤维(A和c纤维)传人脊髓,进而引起痛觉。痛觉是由于痛觉感受器受刺激而诱发的,其他感受器受到

发表于:2019-02-24 / 阅读(51) / 评论(0) 分类 英语听力文摘 English Digest