Other than Mr.Museveni and Zambia's President Banda, the only other African Union member state presidents to sign the IDP convention were Zimbabwe's Robert Mugabe, Mohammed Abdelaziz of the territory of Western Sahara,and Somalia's Sheikh Sharif Ahmed.

VOA: standard.2009.10.23

No, we call that work positive work. All right, so that means we need to put a negative sign right here, by convention.

历史上有过不同的习惯，这里我们规定,如果环境对系统做功。

麻省理工公开课 - 热力学与动力学课程节选

Whatever the convention is within a system of differences, that's what makes the sign intelligible.

这些惯例存在于一个有差别的系统中，这就让符号变得有意义了。

耶鲁公开课 - 文学理论导论课程节选

Infinity is the force when we're thinking about it and our brains, negative infinity is when we actually plug it into the equation here, and the reason is the convention that the negative sign is just telling us the direction that the force is coming together instead of pushing apart.

说力有多大时，我们想到的,是无穷大，而方程解出来的,是负无穷，这是因为习惯上,我们用负号表示力的方向,是相互吸引而不是相互排斥的,所以我们可以用库仑定律。

麻省理工公开课 - 化学原理课程节选

Convention, OK, this negative sign is just a pure convention. You just got to use it all the time. If you use an old textbook, written when I was taking thermodynamics, they have the opposite convention, and it's very confusing. But now we've all agreed on this convention, and work is going to be with the negative sign here.

系统对外界做功的符号为负,这就是我们,在本课中的规定，纯粹出于统一符号的需要，有些教科书中，可能会使用相反的符号规定,注意不要混淆了，这门课上,我们将一直使用。

麻省理工公开课 - 热力学与动力学课程节选