烟草丛顶病(TBTV)传毒特性及寄主范围研究

通过烟草丛顶病中间寄主、烟蚜传毒特性及重要物理性状的试验，得出烟草丛顶病毒的寄主范围是茄科植物：烟蚜的最短传毒时间为2min，最短获毒时间为1h，蚜虫的传毒持久期在9d以上，无翅蚜、有翅蚜均可传毒，新生胎蚜不传毒；该病毒的稀释限点为10^-3，致死温度为70℃；烟草丛顶病毒可以通过汁液摩擦传播，但蚜虫取食汁液摩擦发病株后，不会将病毒传给健株。     

降低稀释蒸汽压力对乙烯装置的影响

上海石化2号烯烃联合装置,通过降低稀释蒸汽压力,减少中压蒸汽使用量,使裂解炉热效率提高了0．275％,同时含油污水排放减少10L／h,为推进装置的节能降耗、节水减排工作做出贡献,同时解决了长期影响裂解炉运行的对流段结焦的问题,延长了裂解炉运行周期。     

Temporal variations in natural attenuation of chlorinated aliphatic hydrocarbons in eutrophic river sediments impacted by a contaminated groundwater plume

Chlorinated aliphatic hydrocarbons (CAHs) often discharge into rivers as contaminated groundwater baseflow. Biotransformation, sorption and dilution of CAHs in the impacted river sediments have been reported to reduce discharge, but the effect of temporal variations in environmental conditions on the occurrence and extent of those processes in river sediments is largely unknown. We monitored the reduction of CAH discharge into the Zenne River during a 21-month period. Despite a relatively stable influx of CAHs from the groundwater, the total reduction in CAH discharge from 120 to 20 cm depth in the river sediments, on average 74 ± 21%, showed moderate to large temporal variations, depending on the riverbed location. High organic carbon and anaerobic conditions in the river sediments allowed microbial reductive dechlorination of both chlorinated ethenes and chlorinated ethanes. δ¹³C values of the CAHs showed that this biotransformation was remarkably stable over time, despite fluctuating pore water temperatures. Daughter products of the CAHs, however, were not detected in stoichiometric amounts and suggested the co-occurrence of a physical process reducing the concentrations of CAHs in the riverbed. This process was the main process causing temporal variations in natural attenuation of the CAHs and was most likely dilution by surface water-mixing. However, higher spatial resolution monitoring of flow transients in the riverbed is required to prove dilution contributions due to dynamic surface water-groundwater flow exchanges. δ¹³C values and a site-specific isotope enrichment factor for reductive dechlorination of the main groundwater pollutant vinyl chloride (VC) allowed assessment of changes over time in the extent of both biotransformation and dilution of VC for different scenarios in which those processes either occurred consecutively or simultaneously between 120 and 20 cm depth in the riverbed. The extent of reductive dechlorination of VC ranged from 27 to 89% and differed spatially but was remarkably stable over time, whereas the extent of VC reduction by dilution ranged from 6 to 94%, showed large temporal variations, and was often the main process contributing to the reduction of VC discharge into the river.