Laboratory ware made from fused quartz and fused silica; straight bore stopcocks made from fused quartz
由熔融石英和熔融石英制成的实验室器皿；由熔融石英制成的直孔旋塞阀

1979-04-01

Laboratory ware made from fused quartz and fused silica; beakers made from fused quartz
由熔融石英和熔融石英制成的实验室器皿；由熔融石英制成的烧杯

1981-11-01

Laboratory ware made from fused quartz and fused silica; boiling flasks made from fused quartz; round bottom flasks, flat bottom flasks and conical flasks
由熔融石英和熔融石英制成的实验室器皿；由熔融石英制成的沸腾烧瓶；圆底烧瓶、平底烧瓶和锥形烧瓶

1981-11-01