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71.
By using observational data and MM5, an observational analysisand numerical study was conducted on the synoptic condition of a severe dust storm that was caused by a Mongolian cyclone whichoccurred from 6 to 8 April 2001. Results illustrated thatthe cyclogenesis was due to the isentropic potential vorticity (IPV) advection in the upper troposphere and the terrain modifiedbaroclinicity in the mid-lower troposphere. The Altai-Sayan complex of mountains blocked the lower level cold air and made the isentropic surface sharply steep. When the air slid down along the isentropic surface the increasing of baroclinicity anddecreasing of stability blew up the vertical vorticity development.The formation of the dust storm was a result of a cyclonic cold front passing across the area. The occurrence of this dust stormwas closely related to the strong surface wind, which was accompanied by a cold front passing, rather than the cyclogenesis, itself. Hence, the reason for the pre-front dust storm formulation was the formation of heating convection. Reasons behind the formation of a black storm (visibilitylower than 50 m), which occurred in the mid-north part ofInner Mongolia, lay in several aspects. Firstly, in thisarea the surface wind was strong, a direct result of thedownward transport in mid-lower troposphere. Secondly,the cold front passed over the effected area near sunsetso the air obtained much more surface heating to form adeeper mixed layer (ML). Thirdly, cooperation between thelower level wind and the terrain made the atmosphere inthis area and acquired the maximum advective contributionnecessary to form a deep post-front ML. The sensitivityexperiment revealed that surface heat flux was important to the frontal lifting. In addition, the forcing of surface heating wasalso seen as the primary forcing mechanism of frontogenesis. Meanwhile, removal of the surface heat flux made the atmosphericstratification became stable and the pre-storm ML very shallow,which weakened the strength of the dust storm.  相似文献   
72.
再燃法烟气脱硝技术   总被引:4,自引:0,他引:4  
综述了再燃法烟气脱硝技术及其主要影响因素。通过对几种脱硝技术的分析比较,认为再燃脱硝是一种很有前景的脱硝技术,其投资和运行费用界于低NO。燃烧器和选择性催化还原技术之间,有喷氨条件下的先进再燃脱硝效率接近于选择性催化还原技术。总结了国内外对先进再燃脱硝技术各种参数影响条件的研究结果,并论述了该技术的应用要点。  相似文献   
73.
The performance of a wetland system in treating lead (Pb)/zinc (Zn) mine drainage was evaluated by using the polyurethane foam unit (PFU) microbial community (method), which has been adopted by China as a standardized procedure for monitoring water quality. The wetland system consisted of four cells with three dominant plants: Typha latifolia, Phragmites australis and Paspalum distichum. Physicochemical characteristics [pH, EC, content of total suspended solid (TSS) and metals (Pb, Zn, Cd, and Cu)] and PFU microbial community in water samples had been investigated from seven sampling sites. The results indicated that the concentrations of Pb, Zn, Cd, Cu, and TSS in the mine drainage were gradually reduced from the inlet to the outlet of the wetland system and 99%, 98%, 75%, 83%, and 68% of these metals and TSS respectively, had been reduced in concentration after the drainage passed through the wetland system. A total of 105 protozoan species were identified, the number of protozoa species and the diversity index (DI) gradually increased, while the heterotrophic index (HI) gradually decreased from the inlet to the outlet of the wetland system. The results indicated that DI, HI, and total number species of protozoa could be used as biological indicators indicating the improvement of water quality.  相似文献   
74.
The status of combined heavy metal and organo-chlorine pesticide (OCPs; i.e. HCH and DDT) pollution was investigated and the soil environmental quality of the Taihu Lake watershed, one of the most developed regions in China, was evaluated using a fuzzy comprehensive assessment. Statistical analyses showed the presence of combined pollution in the soil. At many sampling sites, heavy metal concentrations were above corresponding background values, indicating the effects of extraneous pollutants. It has been over 20 years since China banned the use of OCPs, but they can still be found in soil samples of this region. HCH levels at all investigated sites were below the Chinese Environmental Quality Standard for Soils. Fuzzy comprehensive assessment showed that the overall soil quality in this region could be categorized as class I. Nevertheless, the high coefficients of variation for levels of DDT, Cd and Hg indicated the existence of some point-source pollution. Continuous monitoring and further studies of the region are recommended to prevent pollution of farmland from these sources.  相似文献   
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This study aimed at finding effective strategies for high-performance removal of reactive blue 19 (RB19) dye from aqueous solution. Chitosan (CS) films had been prepared by using solvent casting with mild drying for this purpose. The CS films were characterized by X-ray diffraction, field-emission scanning electron microscopy, and Fourier transform infrared (FTIR) spectroscopy. The performance of RB19 removal using CS were evaluated by varying contact time, solution pH, initial dye concentration, and adsorbent dosage. Adsorption isotherms, kinetics, and desorption were investigated by batch experiments. Results showed that CS films exhibited the optimal adsorption performance for RB19 removal and high maximum adsorption capacities of RB19, which were 799 and 822.4 mg g?1 at 20 and 40 °C, respectively. Adsorption kinetic data were well described by the pseudo-second-order kinetic model. FTIR analyses further indicated that interactions between RB19 and the CS film occurred during adsorption. The CS films also exhibited satisfactory desorption of RB19 at about 80 % after 30 min of desorption at pH 11. Our study demonstrated that the CS films can be easily prepared and applied for effective removal of RB19 in treatment of wastewater.  相似文献   
79.
The fifth meeting of INRA’s national network of ecotoxicologists took place on 25 to 27 November 2014 in Biarritz, France. The main aim of the meeting was to bring together ecotoxicologists from INRA and associated partners, providing them ample opportunity to share and discuss their latest scientific results as well as the national policy of research in ecotoxicology and to precise perspectives for the network.  相似文献   
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