Glaze is mostly translucent, but da Vinci would also slip in small amounts of pigments, such as manganese and lead oxides.

釉料大多是半透明的，但达芬奇也会添加少量色素，如锰，氧化铅。

youdao

Catalytic converters reduce carbon monoxide, oxides of nitrogen, and volatile organic compounds in emissions and necessitated the use of lead-free fuel.

催化转炉减少了一氧化碳，氧化氮和挥发性有机混合物等的排放，而且无铅燃料的应用也当成为必要。

youdao

Serial colour-glazes were tested in that the colouring materials are common metal-oxides, the basic glaze are lead-free, cadmium-free, zinc-free and low-magnesium frit-glazes.

以普通着色金属氧化物为色剂，基釉为无铅无镉无锌低镁透明熔块釉，研制了系列透明色釉。

youdao

Glaze is mostly translucent, but da Vinci would also slip in small amounts of pigments, such as manganese and lead oxides.

ECONOMIST: The da Vinci method

The researchers examined the prevailing inspection system called On-Board Diagnostics II (OBD-II), which tests for excessive carbon monoxide, hydrocarbons, and nitrogen oxides, and also checks the power-train systems for problems that might eventually lead to elevated emissions levels.

FORBES: Competition Leads to Workplace Corruption, Research Shows