科技大爆炸

1 英语原意

包络线：envelope

2 单词的含义

An envelope is something that envelops, or wraps around. It usually refers to the thing you stick a stamp on and snail mail.

含义1: a flat usually paper container (as for a letter)（平常的信件）

含义2: something that envelops : WRAPPER（包裹）

the envelope of air around the earth（地球周围的空气包裹）

含义3 a: the outer covering of an aerostat（飞行器外壳）

b: the bag containing the gas in a balloon or airship（气球或飞艇中装有气体的袋子）

含义4 a: a natural enclosing covering (such as a membrane, shell, or integument)（天然封闭覆盖物（如膜、壳或外皮））

b: a lipoprotein unit membrane that forms the outer layer of some virions（形成一些病毒粒子外层的脂蛋白单位膜）

含义5 a: a curve tangent to each of a family of curves（与曲线族中的每一条相切的曲线）

b: a surface tangent to each of a family of surfaces（与一系列表面中的每个表面相切的表面）

含义6: a set of performance limits (as of an aircraft) that may not be safely exceeded（一组不能安全超过的性能限制（比如飞机））

also : the set of operating parameters that exists within these limits（存在于这些限制内的操作参数集）

含义7: a conventionally accepted limit（约定俗成的限值）

new computers that push the envelope

4 包络线英文解释 Envelope of a Family of Curves

Consider a one-parameter family of plane curves defined by the equation

f(x,y,C)=0

where C is a parameter.

The envelope of this family of curves is a curve such that at each point it touches tangentially one of the curves of the family (Figure 1).

Example: Find the envelope of the family of ellipses defined by the equation

x²/a²+y²/b²=1

provided that a²+b²=1

the final equation of the envelope is given by

|x|+|y|=1

This equation describes a square

4 包络线中文解释

在几何学，某个曲线族的包络线（Envelope），是跟该曲线族的每条线都有至少一点相切的一条曲线。

参考文献：https://math24.net/envelope-family-curves.html