LD50

例句：

1. 1. The LD50 for this chemical is 200 mg/kg.
   这种化学物质的半数致死量为200毫克/千克。
2. 2. The study found that the LD50 of the pesticide was 100 ppm.
   研究发现，该农药的半数致死浓度为100ppm。
3. 3. The LD50 value for this compound is higher than that of its parent compound.
   这种化合物的半数致死值高于其母体化合物。