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851.
Electrochemical reduction characteristics and mechanism of nitrobenzene compounds in the catalyzed Fe-Cu process 总被引:2,自引:0,他引:2
The reduction of the nitrobenzene compounds (NBCs) by the catalyzed Fe-Cu process and the relationship between the electrochemical reduction characteristics of NBCs at copper electrode and reduction rate were studied in alkaline medium(pH=11). The catalyzed Fe-Cu process was found more effective on degradation of NBCs compared to Master Builder's iron. The reduction rate by the catalyzed Fe-Cu process decreased in the following order: nitrobenzene 〉4-chloro-nitrobenzene ≥m-dinitrobenzene :〉 4-nitrophenol ≥2,4-dinitrotoluene 〉2-nitrophenol. The reduction rate by Master Builder's iron decreased in the following order: m-dinitrobenzene ≥4-chloro-nitrobenzene 〉4-nitrophenol 〉2,4-dinitrotoluene ≈nitrobenzene 〉2-nitrophenol. NBCs were reduced directly on the surface of copper rather than by the hydrogen produced at cathode in the catalyzed Fe-Cu process. The reduction was realized by the hydrogen produced at cathode and Fe(OH)2 in Master Builder's iron, It is an essential difference in reaction mechanisms between these two technologies. For this reason, the reduction by the catalyzed Fe-Cu depended greatly on NBC's electron withdrawing ability. 相似文献
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通过对住宅装修噪声与振动的调查监测分析,弄清住宅装修噪声源的特点、对周围声环境和居民的影响程度以及振动污染状况,并提出了防治方案. 相似文献
855.
根据我国的国情开发、研制了CDS-Ⅱ系列除尘、脱硫一体化装置,论述了该装置研制的原则,介绍了该装置的技术指标及特点,并用实例加以说明。 相似文献
856.
介绍了 3种先进的连接管件成形技术 ,即小弯曲半径管内压推弯成形技术、球形管接头的胀形成形技术和管件的内径滚压成形技术 ,对其基本成形过程进行了描述 ,并通过铝合金、不锈钢和钛合金管件的成形试验获得了主要工艺参数对成形的影响规律 ,结果表明采用这些方法成形所需的连接管件是非常有效的 相似文献
857.
Peroxyacyl nitrates (PANs) are important secondary pollutants in ground-level atmosphere. Accurate prediction of atmospheric pollutant concentrations is crucial to guide effective precautions for before and during specific pollution events. In this study, four models based on the back-propagation (BP) artificial neural network (ANN) and multiple linear regression (MLR) methods were used to predict the hourly average PAN concentrations at Peking University, Beijing, in 2014. The model inputs were atmospheric pollutant data and meteorological parameters. Model 3 using a BP-ANN based on the original variables achieved the best prediction results among the four models, with a correlation coefficient (R) of 0.7089, mean bias error of ? 0.0043 ppb, mean absolute error of 0.4836?ppb, root mean squared error of 0.5320?ppb, and Willmott's index of agreement of 0.8214. Based on a comparison of the performance indices of the MLR and BP-ANN models, we concluded that the BP-ANN model was able to capture the highly non-linear relationships between PAN concentration and the conventional atmospheric pollutant and meteorological parameters, providing more accurate results than the traditional MLR models did, with a markedly higher goodness of R. The selected meteorological and atmospheric pollutant parameters described a sufficient amount of PAN variation, and thus provided satisfactory prediction results. More specifically, the BP-ANN model performed very well for capturing the variation pattern when PAN concentrations were low. The findings of this study address some of the existing knowledge gaps in this research field and provide a theoretical basis for future regional air pollution control. 相似文献
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以黄鳝为试验材料,研究了艾割和使它隆二种除草剂对鱼类的致突变性。对经腹腔注射染毒上述二种除草剂的受试黄鳝,通过对其活体肾细胞染色体数目和形态的观察,分析其突变率。研究结果(经t检验)显示:艾割和使它隆二种除草剂分别在其试验最低受试剂量50mg/kg和8.0mg/kg即可引起黄鳝的染色体畸变。采用SOS/Umu显色试验研究,在SOS/Umu试验中,使它隆和艾割2个受试除草剂可以诱发SOS阳性反应,且呈明显的剂量-效应关系。试验表明这二种除草剂具有遗传毒性,应对这二种除草剂严加管控,避免其对环境的影响。 相似文献
860.
介绍了工件在拉深过程中 ,由于坯料在外力的压应力作用下所产生失稳而引发起皱的原因 ,并就防止起皱提出了增加压边力、拉应力等相应措施 相似文献