有害、危险环境下稀薄气体的探测一直以来都是微纳米器件研究领域的热门课题。近年来气体敏感材料切片在气体吸附脱附过程中表现出来的优异特性，特别是良好的介电特性，使得采用气敏法来检测瓦斯气体的浓度成为研究的焦点。 气敏法检测瓦斯气体浓度中气敏材料的选取对气体浓度探测精度至关重要，而作为新型气敏材料的SiC对气体有良好的吸附特性，在敏感元件领域具有非常高的研究价值。本文中以3种不同比例掺杂Ni原子的SiC(001)切面为气体敏感吸附基底，使用Material Studio软件构建(3×3)的超晶胞，利用基于第一性原理的密度泛函理论方法模拟计算了CO和CH4分子在掺杂材料表面的吸附性能。优化模型后分别从吸附系统结构变化、吸附能、电荷密度差以及态密度等几个方面，对比分析气体分子在掺杂材料表面4个不同经典吸附位置(Top、Bridge、Hcp、Fcc)的吸附特性。在对CO分子进行化学吸附时得出，在1/9掺杂时Fcc位为最佳吸附位置；1/3掺杂时Bridge位为最佳吸附位置；2/3掺杂时Hcp位为最佳吸附位置；通过不同比例掺杂的对比，得出2/3掺杂比例时对SiC (001)切面的影响最大，不仅在吸附CO分子后系统更加稳定，而且吸附过程中电子转移速度加快，作为敏感吸附材料时，电阻率将发生明显的变化。在对CH4分子进行Top位物理吸附时得出，无论是从结构的变化还是从作用过程中态密度的变化都表明1/9掺杂时的SiC (001)对CH4的物理吸附更稳定。 在采集电路的设计上，耦合仪表放大器与差动放大器采集气体敏感器件输出的微弱电压信号并进行逻辑放大，采用内含模数转换功能的微控制器STM32进行电压采集，将采集到的电压信号输出显示在4位一体数码管上，当采集到的电压值超过报警阈值时进行声光报警。在Keil软件中编写相应的电压采集和显示输出程序，利用基于STM32的最小系统、电位器以及4位一体数码管搭建实物系统对软件程序进行测试，结果表明该系统可实现对稀薄瓦斯气体的探测和报警。本研究成果可应用于矿业生产生活中，特别是煤矿开发方面可以减少有害气体的积累和爆炸的可能性，使得开采环境更加安全。

Rarefied gas detected in harmful and dangerous environment has been gotten extensive attention in the research field of the micro/nano device.In recent years,gas sensitive method for detecting the concentration of the gas becomes the focus of research, for its excellent properties, especially good dielectric properties that gas sensitive materials slips displayed in the process of gas adsorption. Gas sensitive material is important for gas sensitive method to detect the gas concentration. SiC, as a new type of gas sensitive material, has the very high research value in the field of sensitive element because of the good adsorption properties for gases. In the article, three kinds of different proportion of doped Ni atom of SiC(001) planes are designed as gas sensitive adsorption substrate. Supercells of (3×3) that CO and CH4 adsorb on the surfaces of the doped Material built with Material Studio, are simulated by the method of density functional theory based on first principles. After optimizing the model, 4 different classical adsorption position (Top, Bridge, Hcp and Fcc) adsorption properties are analyzed through the bond structure change, adsorption energy, electron density difference, density of state and so on. For the chemical adsorption of CO molecule, the Fcc is the best adsorption position for 1/9 doping; The Bridge is the best adsorption position for 1/3 doping; The Hcp is the best adsorption position for 2/3 doping; By comparing different proportion of doping material, it is obtained that the 2/3 doping ratio have significant impact for SiC(001). The system is not only more stable after the adsorption of CO molecule, but also electron transfer in the process of adsorption is more rapid. And, as a sensitive adsorption material, the resistivity can generate an obvious change. For the physical adsorption of CH4 molecule on Top position, the change of the geometry and of the density of state of SiC show that 1/9 doped SiC(001) of physical adsorption of CH4 is more stable. In the design of acquisition circuit, the weak voltage signal from the gas sensitive components is amplified by instrumentation amplifier and differential amplifier. The microcontroller STM32, embedded modulus conversion function collects the data of voltage.The data will been shown by four integrated digital tube, and the sound and light alarm signals will been triggered when the voltage value collected exceeds the designed value. Program for voltage acquisition and display are performed in Keil software, and verifed based a cyber-physical system which is made up of smallest system of STM32, potentiometer and four digital tube structures was used to detect the concentration of gas. The results show that the designed system will excellently detect the low concentration of gas. The research results can be used in the mining production and living, especially coal mine safety. It can make the mining environment safer, and reduce the probability of harmful gas accumulation and explosion.