What is the fine-grained topic of the following text: Key companies profiled on his report are Linde Group, Air Liquide, Praxair, Air Products And Chemicals, Taiyo Nippon Sanso, Air Water, Airgas, Messer, Yingde Gases and more in the terms of Product Introduction, Application, Specification, companies Production, Revenue, Price and Gross Margin (2014-2019), etc. Only return the topic.
Company profiling in the gas production industry