The invention relates to a nitrating method of a valvemetal powder, and a nitrogenous tantalum powder and a nitrogenous niobium powder which are obtained by the nitrating method.
本发明涉及阀金属粉末的掺氮方法，以及通过该方法获得的含氮钽粉 和含氮铌粉。
2
The procedure involves an artificial aortic valve, made from pieces of a cow's valve sewn to a metal frame.
该过程涉及到使用一只人工制作的主动脉瓣，它是由一个缝在金属框架里的牛的脉瓣制成的。
3
Valve Advantages: The replacement of elastomeric packings by metal diaphragms gives this valve superior leak integrity at the top works of the valve and stem.