对教育部《职业学校学生顶岗实习管理规定（试行）》的解读

从政策出台的背景、高职院校学生顶岗实习中学校的职责和实习生权益的保障方面，解读教育部《职业学校学生顶岗实习管理规定（试行）（征求意见稿）》，以期为职业院校深入理解和贯彻执行此项政策提供参考。     

LAS共代谢降解菌的降解动力学研究

研究2株直链烷基苯磺酸钠(LAS)共代谢降解菌的降解动力学.分别对2株直链烷基苯磺酸钠共代谢降解菌克雷伯氏菌属(Klebsiella sp.)和肠杆菌属(Enterobacter sp.)进行研究,通过正交实验考察了其最佳降解条件,并进行降解动力学研究.当温度为30℃,p H值为7.5,装液量为50 m L时,最适合两株细菌降解LAS.其中菌株L-2在生长基质葡萄糖质量浓度为500 mg/L时,对50 mg/LLAS降解率为94.2%;菌株L-15在生长基质葡萄糖质量浓度为1 000 mg/L时,对50 mg/LLAS降解率为92.2%;当LAS质量浓度在25~100 mg/L范围内,2菌株降解反应符合一级动力学特征.本研究可为全基质生活污水处理LAS废水提供一定的理论依据.     

Different Performances of H2O2 to Oxidise Aldicarb and Hexazinone in the Advanced Oxidation Process of Ozone/Hydrogen Peroxide

The degradations of hexazinone and aldicarb by direct ozonation combined an advanced oxidation process（ AOP） of O3/H2O2 were investigated in this study focusing on the oxidation mechanism by identifying the hydrogen peroxide consumption during the oxidation process of the two chemicals. The results showed that H2O2 could enhance the removal rate of the triazine herbicide hexazinone,and it was consumed along with the variation of removal rate in the light of different pH levels. The addition of H2O2 contributed little to the removal of the thiocarbamate herbicide aldicarb and H2O2 content kept constantly throughout the degradation process. Tert-butyl alcohol（ TBA） effectively scavenged the ·OH radical for hexazinone,but had no effect on the removal rate of aldicarb. Aldicarb removal was mainly attributed to direct ozonation molecule in both O3（ 97.00%） and O3/H2O2（ 96.76%）systems. Moreover,sole O3 could hardly oxidize hexazinone whereas·OH radicals contribute respective 74.70% and 97.50% of removal in O3 system and O3/H2O2 AOP. All of these findings suggest that the mechanism of ·OH radical generation and the chain reaction in O3/H2O2 AOP should be further discussed.     

Inactivation of Giardia by Ozone and Its Disinfect Mechanisms

This study was to investigate the effect of ozone(O3)inactivation on Giardia in water by the fluorescence staining method.In order to elucidate the dominant mechanisms of inactivation,cell surface or inner cell components damage were comparatively examined by scanning electron microscopy(SEM).Results suggested that O3had a stronger effect on inactivating capability.Firstly,when the concentration of O3was above 2.0 mg/L and the contact time was up to 5 min,it showed a significant inactivating effect.Secondly,the effect of turbidity on inactivation was also found to be significant in synthetic water;when turbidity increased,the inactivating effect decreased.Thirdly,the inactivating rates were improved with a temperature increase from 5 to 25℃,but decreased when the temperature were out of this range.The inactivating capability of O3was stronger under acidic conditions than alkalic conditions.Lastly,when the concentration of organic matter in the reactive system was increased,probably due to the competition between Giardia and organics on O3,the inactivating rate was decreased;in addition,the cellular morphology of Giardia varied with different contact times.At contact time of 30 s,cells were rotundity and sphericity;at 60 s they became folded,underwent emboly,and burst;and at 240 s,the cell membrane of Giardia shrinked and collapsed completely.