Some end value condition derived by variational method in accordance with the least energy loss principle and their mechanical background are also dealt with.
同时从能量最小原理出发，用变分的方法推导出几种端值条件，说明它们的力学背景。
2
The expression of ground energy is given by means of variational method, and the condition of formation of photon pairs discussed.
然后利用变分法求得了超导波态系统的基态能量表达式，并讨论了光子对的形成条件。
3
Then its generalized variational principle is established on the basis of Lagrange multiplier method by absorbing the first kind of boundary condition.