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The influence of metal ions, such as Fe2+ , Fe3+ , Cu2+ and Mn2+ , on 4-CP degrada- tion was investigated in an aqueous pulsed discharge plasma system with or without the addition of a TiO 2 photo-catalyst. From an analysis of the pseudo first-order rate constant (k CP ) and energy efficiency (G 50% ) for 4-CP degradation, the experimental results show that the degradation of 4-CP is much enhanced in the presence of ferrous ions at the optimal concentration of 0.2~0.8 mmol/L or 0.2 mmol/L in an aqueous pulsed discharge plasma without or with the TiO2 system, respectively, and the enhancement is ascribed to plasma induced Fenton and photo-Fenton reactions. Meanwhile, the rank of such metal ions for catalytic effect on 4-CP degradation was Fe2+ > Fe3+ > Cu2+ > Mn2+ and Fe2+ > Fe3+ > Mn2+ > Cu2+ for the former and the latter systems, respectively, and the reasons behind this were discussed through the analysis of active species, especially hydrogen peroxide. 相似文献
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为获得超高速涡轮泵中超音速喷嘴流出系数随其入口收敛角、喉部直径等几何结构参数的变化规律,采用ANSYS CFD仿真分析工具,以氦气为工质,给定喷嘴入口总压11 MPa、总温300 K、排气背压0.105 MPa,对3种特定喉径的喷嘴分别在7种入口收敛角度下的流场进行仿真分析,获得其压力场、速度场分布及氦气质量流量,并将其与理论质量流量比较,得出喷嘴流出系数。3种特定的喉径分别为2,5,10 mm,7种入口收敛角分别为30°,45°,60°,90°,120°,150°,180°。结果表明:喷嘴流出系数随入口收敛角的增加而降低,随喉径的增大而增加,在2 mm喉径下流出系数最低为83.9%,在10 mm喉径下流出系数最高为99.1%,对后续设计超高速涡轮泵喷嘴结构形式具有指导作用。 相似文献
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钠盐浓度对厌氧产氢颗粒污泥从蔗糖中产氢的影响 总被引:3,自引:0,他引:3
This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na ), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000-2000mg·L-1(Na )] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6-413.1mg·L-1·h-1, 28.04-28.97ml·g-1, 7.52-7.83ml·g-1·h-1, respectively. The specific production yields of propionate, butyrate and valerate decreased, with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration. 相似文献
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针对传统基于角色的访问控制(RBAC)模型在大规模企业应用及复杂业务权限控制中的不足,本文引入了RULES和GROUPS属性对其进行延伸和拓展,形成了改进的RBAC模型。通过RULES对数据范围细化,解决了细粒度复杂业务中的权限控制,通过GROUPS定义层次结构模型,实现了大规模授权中的分级管理。基于此模型构建了统一视频监控平台权限管理框架,讨论了其功能组成、分级管理授权过程及细粒度权限控制过程,通过项目验证了其可行性与有效性。 相似文献
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