7-23 1400 0.01542 0.400 0.8667 18.72 1700 0.01128 0.355 0.8817 16.92 ¢ 2 2 n = 8.0 f = 126 กก./ซม f = 280 กก./ซม c C 1200 0.0240 0.4575 0.8475 24.80 1260 0.0222 0.4444 0.8519 23.80 1400 0.0188 0.4186 0.8605 22.63 1700 0.0139 0.3750 0.8750 20.70