pH2O_100_hum =EXP(52.57-(6690.9/(app.Temp+273.15))-4.681*LN(app.Temp+273.15))
pH2O_real =pH2O_100_hum*app.RelHumidityEditField.Value
T_O2soly =LN((298.15-O20)/(273.15+app.Temp))
O2_soly_umol_kg =EXP(5.80818 + 3.20684*T_O2soly + 4.1189*T_O2soly^2 + 4.93845*T_O2soly^3 + 1.01567*T_O2soly^4 + 1.41575*T_O2soly^5)
Density_waterkg_L =(999.84847+0.06337563*app.Temp-0.008523829*app.Temp^2+0.00006943248*app.Temp^3-0.0000003821216*app.Temp^4)/1000
O2_soly_uM =O2_soly_umol_kg*Density_waterkg_L
O2raw_air_uM =app.O2_mL_L_aircal*44.6596
Gain =(O2_soly_uM*(app.AtmpressureEditField.Value-pH2O_real))/((1013.25-pH2O_100_hum))/O2raw_air_uM

O20 = app.Temp
X20 = pH2O_100_hum
U20 = app.RelHumidityEditField.Value
Z20 = T_O2soly
AA20 = O2_soly_umol_kg
AB20 = Density_waterkg_L
N20 = app.O2_mL_L_aircal
AC20 = O2_soly_uM
T20 = app.AtmpressureEditField.Value
AD20 = O2raw_air_uM
Y20 = pH2O_real