Co = 7.325 10^-11;
Vfb = 0.6;
testing =
Import["D:\\Ph.D\\mathematica\\trapz test.xls", {"Data"}][[1,
Range[1, 121], {1, 2}]];
V = Import["D:\\Ph.D\\mathematica\\trapz test.xls", {"Data"}][[1,
Range[1, 121], 1]];
tit = {#[[1]], 1 - #[[2]]/Co} & /@ testing;
daba = Interpolation[tit];
If[Vfb > V[[50]],
NIntegrate[daba[x], {x, #, Vfb}] & /@ V, NIntegrate[daba[x], {x, Vfb, #}] & /@ V]
{4.14399, 4.05774, 3.9716, 3.8856, 3.79973, 3.71398, 3.62834, 3.5428, \
3.45739, 3.3721, 3.28697, 3.202, 3.11716, 3.03246, 2.94794, 2.86357, \
2.77937, 2.69537, 2.6116, 2.52801, 2.44457, 2.36137, 2.27839, \
2.19564, 2.11316, 2.03093, 1.94896, 1.86729, 1.78595, 1.7049, \
1.62418, 1.54385, 1.4639, 1.38431, 1.30518, 1.22652, 1.14835, \
1.07075, 0.993778, 0.917464, 0.841892, 0.76716, 0.693377, 0.620636, \
0.549054, 0.478927, 0.410872, 0.345897, 0.285159, 0.229677, 0.180024, \
0.136453, 0.0989801, 0.0672554, 0.0406667, 0.0184875, 0, -0.0155074, \
-0.0286217, -0.0398094, -0.0494886, -0.0578936, -0.0652406, \
-0.0717571, -0.0775415, -0.082727, -0.0874261, -0.0916792, \
-0.0955688, -0.0991007, -0.102323, -0.105321, -0.108068, -0.110609, \
-0.113013, -0.115267, -0.117346, -0.119291, -0.121105, -0.122803, \
-0.124414, -0.125931, -0.127336, -0.128635, -0.129893, -0.131082, \
-0.132178, -0.133232, -0.134207, -0.135112, -0.135987, -0.136807, \
-0.137573, -0.138253, -0.138891, -0.139528, -0.14013, -0.140682, \
-0.1412, -0.1417, -0.142155, -0.142593, -0.143003, -0.143371, \
-0.143713, -0.144011, -0.144298, -0.144574, -0.144796, -0.145009, \
-0.145199, -0.145383, -0.145563, -0.145706, -0.145812, -0.145929, \
-0.146035, -0.146078, -0.146128, -0.146155, -0.146155}
If[Vfb > V[[60]], NIntegrate[daba[x], {x, #, Vfb}] & /@ V, NIntegrate[daba[x], {x, Vfb, #}] & /@ V]
{-4.14399, -4.05774, -3.9716, -3.8856, -3.79973, -3.71398, -3.62834, \
-3.5428, -3.45739, -3.3721, -3.28697, -3.202, -3.11716, -3.03246, \
-2.94794, -2.86357, -2.77937, -2.69537, -2.6116, -2.52801, -2.44457, \
-2.36137, -2.27839, -2.19564, -2.11316, -2.03093, -1.94896, -1.86729, \
-1.78595, -1.7049, -1.62418, -1.54385, -1.4639, -1.38431, -1.30518, \
-1.22652, -1.14835, -1.07075, -0.993778, -0.917464, -0.841892, \
-0.76716, -0.693377, -0.620636, -0.549054, -0.478927, -0.410872, \
-0.345897, -0.285159, -0.229677, -0.180024, -0.136453, -0.0989801, \
-0.0672554, -0.0406667, -0.0184875, 0, 0.0155074, 0.0286217, \
0.0398094, 0.0494886, 0.0578936, 0.0652406, 0.0717571, 0.0775415, \
0.082727, 0.0874261, 0.0916792, 0.0955688, 0.0991007, 0.102323, \
0.105321, 0.108068, 0.110609, 0.113013, 0.115267, 0.117346, 0.119291, \
0.121105, 0.122803, 0.124414, 0.125931, 0.127336, 0.128635, 0.129893, \
0.131082, 0.132178, 0.133232, 0.134207, 0.135112, 0.135987, 0.136807, \
0.137573, 0.138253, 0.138891, 0.139528, 0.14013, 0.140682, 0.1412, \
0.1417, 0.142155, 0.142593, 0.143003, 0.143371, 0.143713, 0.144011, \
0.144298, 0.144574, 0.144796, 0.145009, 0.145199, 0.145383, 0.145563, \
0.145706, 0.145812, 0.145929, 0.146035, 0.146078, 0.146128, 0.146155, \
0.146155}