The optimummix and the main effect factor is determined by the strength at 28 days and verified by the regression strength at 90 days.
由28 天强度确定了最佳配比和主要影响因素，用回归90 天的强度进行了验证。
2
The influence of hair fibre with different mix amount and length on the bending strength of cement were studied experimentally and the optimummix amount and length have been found.
通过实验研究了不同掺量、不同长度的毛发纤维对水泥抗折强度的影响，找出了最佳长度和最佳掺量。
3
There is no fixed recipe in approaching metering in all kinds of situations. It's a mix-n-match of different techniques - all used to make sure I get optimum exposure for my images.