A number of substances have been used as positive contrast agents: silver, bismuth, caesium, thorium, tin, zirconium, tantalum, tungsten and lanthanide compounds have been used as contrast agents.
许多物质已被用来作为阳性造影剂：银，铋，铯，钍，锡，锆，钽，钨和稀土化合物已被使用造影剂。
2
This paper reviews the deoxygenative reduction and dehalogenative reduction of organic compounds with the low valent tungsten reagents.
本文对低价钨试剂与有机化合物的脱氧、脱卤还原反应作了简要的叙述。
3
Tungsten based compounds and alloys with high density have become more and more important for the functional materials due to their excellent physical and chemical properties.