The test of Brinell hardness and strength of plastic contact are used as the main investigative means in this paper, and little deformation of metal is presumed.
以布氏硬度实验、塑性接触变形实验为主要研究手段，以金属的小接触变形为假设前提。
2
Objective To investigative the correlations between QRS duration(QRSD) and heart function and 6-minute walk test(6-MWT)in elderly patients with chronic heart failure(CHF).