The most important tag on a page is your title tag, followed after by the h1 and h2 (not sure on h3, h4 etc.). If you look at a well presented site you ll see that either the site title is in a h1 on every page, and the page title is in a h2, or the

1.AVR单片机：ATMEGA64 2.检测采样气体中H2S，NH3的浓度并显示 3.用MODBUS通信传递到工控机中-1.AVR SCM:. ATMEGA64 2 detected in the sample gas H2S, NH3 concentration and displays three passes with MODBUS communication to the industrial machine.

硫化氢检测仪全部代码，包括（数码管显示，主程序等）(Hydrogen sulfide detecto)