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工程与科技

应力
物体切面每表面积单位所承受的力,一般所用的单位为兆帕(MPa)。与应变的关系可被杨氏模量解释。
应变
物体每长度单位的长度变化,一般由应力所导致。没有单位。
破裂应变
指物体在断裂前能被拉伸的最大长度。与抗拉强度有着细微的不同。虽然在一般情况下,物体在这两种特性上的数值大致相似(比如金属的这两项数值对都相对高,而陶瓷的数值则相对低),但是某些物体的这两项数值则是非常不同(比如木料与CFRP有着相对高的抗拉强度,而它们的破裂应变相对较低)。
抗拉强度
一块材料每表面积单位可承受的最大拉力,指物体在断裂前能被拉伸的最大强度。例如,蜘蛛丝比钢有着更高的抗拉强度,以及橡胶比玻璃纤维有着更高的抗拉强度。
硬度
Hardness is the measurement of how difficult it is to permanently deform a piece of a given material by the application of force. The usual way to measure it is Vickers Hardness (HV)1 - this is done by forcing a pyramid made of a very hard material into the tested sample's surface with a predefined load, measuring the indent's size, and reading the corresponding hardness off a table. A harder material will normally also be more brittle, as they usually can't deform plastically very well. (rubber is an exception). For example, obsidian is harder than copper, but shatters very easily.
纳米技术
Nanotechnology and "nanobots" are not magic. Let me repeat that: NANOTECHNOLOGY AND "NANOBOTS" ARE NOT MAGIC. First, nanotechnology is already in use today in manufacturing and medicine in order to design and build new materials that are difficult to create on a macroscale. Second, "nanobots" are machines, first and foremost, only on a very tiny scale. And size restrictions mean that they don't have very complicated instructions. Most nanomachines in use today rely on manipulating the natural responses of certain molecular/atomic interactions in order to move around other atoms or molecules. Their "programming" tends to be very simple due to their size and info-storage capacity, and they tend to specialize at a very few activities (although multiple different types of machines would be able to work together). And while having a few million nanomachines working in concert could definitely fuck some shit up hardcore, they ultimately operate fully under the known laws of physics.

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