By using the weak maximum principle, the uniqueness and stability of the solution of water vapour equation with the first, second and third boundary-value problems were proven.
利用该弱极大值原理，证明了对于第一类、第二类和第三类边值问题，水汽方程解的唯一性和稳定性。
2
Using the comparison principle, the existence, uniqueness and its asymptotic behavior of solution for the problem are studied.
利用比较原理，研究了问题解的存在性，唯一性及其渐近性态。
3
Due to the structure and working principle, make the uniqueness of spin vibration sieve especially suitable for small particles and the subtle powder material of grading.