Numerical study on NOx/CO emissions in the diffusion flames of high-temperature off-gas of steelmaking converter

The combustion of high-temperature off-gas of steelmaking converter with periodical change of temperature and CO concentration always leads to CO and NOx over-standard emissions. In the paper, high-temperature off-gas combustion is simulated by adopting counterflow diffusion flame model, and some influencing factors of CO and NOx emissions are investigated by adopting a detailed chemistry GRI 3.0 mechanism. The emission index of NOx (EINOx) decreases 1.7–4.6% when air stoichiometric ratio (SR) increase from 0.6 to 1.4, and it dramatically increases with off-gas temperature at a given SR when the off-gas temperature is above 1500 K. High-concentration CO in off-gas can result in high NOx emissions, and NOx levels increase dramatically with CO concentration when off-gas temperature is above 1700 K. Both SR and off-gas temperature are important for the increase of CO burnout index (BICO) when SR is less than 1.0, but BICO increase about 1% when off-gas temperature increases from 1100 K to 1900 K at SR > 1.0. BICO increases with CO concentration in off-gas, and the influence of off-gas temperature on BICO is marginal. BICO increases with the relative humidity (RH) in air supplied, but it increases about 0.5% when RH is larger than 30%.

He-CO散射截面的量子力学研究

采用精确度较高的密耦方法(Close-Coupling)计算了He-CO碰撞的散射截面,能量从5 meV~70meV,计算结果与M.Keil等的实验结果(64 meV)基本相符.研究表明:势能的零点能位置、势阱深度、势阱位置、排斥势强度以及势能在势阱附近的方向性都对散射截面有较大的影响.

Late cenozoic chemical weathering and environmental changes recorded in the Co Ngoin sediments, central Qinghai-Tibet Plateau

IEECAS SKLLQG

重离子~(12)C对~(60)Coγ射线诱发人染色体畸变效应的比较研究

目的　重离子和高剂量率6 0 Coγ射线照射离体人血建立染色体畸变的剂量 效应曲线 ;比较重离子1 2 C照射与6 0 Coγ射线照射诱发染色体畸变的相对生物效能。方法　重离子1 2 C和6 0 Coγ射线照射离体人血 ,吸收剂量率为 3Gy min ,吸收剂量为 1 0～ 8 0Gy。主要记录染色体型畸变的非稳定性畸变 ,对双着丝粒体和着丝粒环做曲线拟合 ,并检验回归系数的显著性和曲线的拟合度。结果　重离子1 2 C和6 0 Coγ射线照射离体血诱发的染色体畸变 (双 +环 ) ,在 0～ 8Gy范围内 ,呈良好的剂量 效应关系。1 2 C离子诱发染色体畸变的RBE值是不恒定的 ,它随吸收剂量增加而减少 ,在 0 3～ 8 0Gy范围内 ,RBE值 (Dγ Dc)从 2 6 2到 1 0 0 ,平均 1 5 8。结论　1 2 C离子对6 0 Coγ射线照射诱发染色体畸变 ,在照射剂量较低时 ,有较高的生物效应。

重离子~(12)C~(6+)对~(60)Coγ射线诱发淋巴细胞微核效应的比较研究

目的　比较重离子束1 2 C6+对60 Coγ射线照射人离体血诱发淋巴细胞微核的效应。方法　用60 Coγ射线和地面加速器产生的重离子1 2 C6+(平均LET为 36 70keV μm) ,不同剂量照射离体人血 ,用CB微核法观察双核淋巴细胞的微核 ,计算重离子束1 2 C6+对60 Coγ射线的相对生物效能。结果　在 0～ 6Gy剂量范围内 ,重离子束1 2 C6+对60 Coγ射线的相对生物效能在 4 1 9～ 1 78之间 ,平均为 2 56。结论　重离子束1 2 C6+比60 Coγ射线有更高的生物效应