关键词: 微分不等式, 奇异摄动, 渐近展开式, 椭圆型微分方程, 非局部边值问题．

Abstract:

in this paper a class of singular perturbation of nonlocal boundary value problems for elliptic partial differentail equations of hingher order is considered by using teh differential inequalities,the uniformly valid asymptotic expansion of solution is obtained .

Key words: 　Ｄｉｆｆｅｒｅｎｔｉａｌｉｎｅｑｕａｌｉｔｙ, Ｓｉｎｇｕｌａｒｐｅｒｔｕｒｂａｔｉｏｎ, Ａｓｙｍｐｔｏｔｉｃｅｘｐａｎｓｉｏｎ, Ｅｌｌｉｐｔｉｃｄｉｆｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎ, Ｎｏｎｌｏｃａｌｂｏｕｎｄａｒｙｖａｌｕｅｐｒｏｂｌｅｍ．