function CommonFun.calcBuff_2445(srcUser, targetUser, a, b, c, d, lv)
  if srcUser == nil or targetUser == nil then
    return 0
  end
  local Rate = 5
  local skilllv_1 = srcUser:GetLernedSkillLevel(432_RUNE_KNIGHT:CHEMICAL_WEAPON_DESTRUCTION)
  local skilllv_2 = srcUser:GetLernedSkillLevel(464_RUNEMASTER:CHEMICAL_SHIELD_DESTRUCTION)
  local Luk = srcUser:GetProperty("Luk")
  local Dex = srcUser:GetProperty("Dex")
  local effect = 0
  if 0 < skilllv_1 and skilllv_1 <= 10 then
    effect = 10 + 5 * skilllv_1
  elseif 10 < skilllv_1 then
    effect = 60 + (skilllv_1 - 10) * 2
  end
  Rate = 5 + math.min(effect, (Luk + Dex) / 5) / 4
  local Weapon = srcUser:GetEquipedID(7_WEAPON)
  if Weapon == 41545_ELDER_S_HAMMER_1 or Weapon == 141545_ELDER_S_HAMMER_2 or Weapon == 41567_ACID_TOUCH_1 or Weapon == 141567_ACID_TOUCH_2 then
    Rate = Rate + 5
  end
  if srcUser:HasBuffID(53370_DARK_MERCHANT_CARD_:MAX_STACK_0) then
    Rate = Rate + 5
  end
  local pos = 0
  if CommonFun.IsInRate(Rate, srcUser:GetRandom()) then
    pos = 7
    if 0 < skilllv_2 and CommonFun.IsInRate(skilllv_2 * 10, srcUser:GetRandom()) then
      pos = 107
    end
  end
  local A = 0
  if srcUser:HasBuffID(90004474_ACID_TOUCH_1_T5_:MAX_STACK_0) then
    A = Rate
  end
  return A
end