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191.
192.
利用载体经干燥后机械强度得到提高的特性,建立一种低胶体浓度固定化微生物制备技术:包埋剂为5.5%PVA、0.45%SA,固定液为饱和硼酸与0.6%硫酸铝的混合液,包菌量为0.4g/mL包埋剂。小球硬化24 h后洗净并放入30℃鼓风干燥箱干燥3.5 h后备用。制备出的固定化微生物氨氧化速率为24.3 mg/(L·h),相对活性为77.7%。 相似文献
193.
Forestry Best Management Practices (BMPs) were developed to protect water quality. In the eastern US, those BMPs were often expanded to include maintenance of site productivity. Generally, BMPs recommend the use of pre-harvest planning and careful design for construction of roads and other activities that expose bare soil, minimizing trafficking and areas of bare soil, maintaining streamside management zones, ensuring rapid revegetation following harvesting, minimizing soil disturbance, and ameliorating severe trafficking with site preparation. This review of peer-reviewed research from the past 20 years examined the effects of forest harvesting and site preparation on water quality and site productivity in the eastern US. The review was subdivided into areas having relatively similar physiography and land management (New England, Lake States, Appalachian Plateau, Ridge and Valley, Blue Ridge, Piedmont, Atlantic Coastal Plain, Gulf Coastal Plain, and Ouachitas-Ozarks). In general, data from steeper physiographic regions indicated that forest harvesting and site preparation can increase erosion, sediment and nutrient losses to streams. However, the quantities introduced into streams tended to be relatively low, generally below the values that are considered acceptable for alternative land uses. Also most research indicated that water quality recovers within two to five years following forest operation disturbances, particularly if BMPs are employed. Research from the less mountainous and often more poorly drained Lake States and Coastal Plain regions indicated that soil compaction and rutting may or may not cause site productivity effects, depending on soil types, natural ameliorative properties and site preparation. Overall, the research supports the forestry BMPs recommended in the eastern states. 相似文献
194.
针对氮氧化物(NOx)废气瞬时爆发性浓度极高、气量大,难于治理的危害特性,设计了一套适合敞开作业的通风净化系统装置。该工程既解决了原有NOx废气处理工艺的难题,提高NOx废气处理技术,又解决了"黄龙"对大气的污染,达到保护环境与社会和谐的统一。 相似文献
195.
以污水处理厂剩余污泥为原料,以氯化锌和氯化铜为复合活化剂,采用低温炭化及中温活化方法制备了污泥活性炭。经正交优化得到最佳制备条件为:活化温度为534℃,活化时间为60 min,ZnCl2浓度为3.0 mol/L,CuCl2浓度为0.3 mol/L,碘吸附值达到534.0 mg/g。所得污泥活性炭含有大量微孔,同时也含有部分中孔和大孔,BET比表面积为784.89 m2/g,Langmuir比表面积为1 053.69 m2/g;利用污泥活性炭吸附制药废水,实验结果符合Freundlich方程,由此建立的分形吸附模型证明制备的污泥活性炭具有分形特征,其分形维数越高,则粗糙度越大,碘吸附值越高。 相似文献
196.
An overview of the methods used for the isolation and characterization of organic matter in natural waters is presented. Commonly used techniques for the concentration and isolation of organic matter from water, such as preparative chromatography, ultrafiltration and reverse osmosis, and the methods used to analyze the organic matter obtained by these methods are reviewed. the development of methods to obtain organic matter that is associated with fractions of the dissolved organic carbon other than humic substances, such as organic bases, hydrophilic organic acids and colloidal organic matter are discussed. Methods specifically used to study dissolved organic nitrogen and dissolved organic phosphorous are also discussed. 相似文献
197.
The pulmonary Cd and Cr content was determined from 53 lung cancer patients operated for cancer and from 39 patients who died of non‐malignant diseases. The results were correlated with smoking habits, pulmonary emphysema and occupational history. Both the pulmonary Cd and Cr increased with the amount of smoking. In ex‐smokers the Cr content in lung tissue did not diminish with the time since stopping smoking, but the Cd did follow the half‐life of about 9 years. The pulmonary Cd, compared with smoking habits, behaved similarly in both the lung cancer and control patients, whereas Cr in the lung cancer patients could not be explained solely by smoking, but some of the cancer patients may have been occupationally exposed to Cr. Speciation was not studied. 相似文献
198.
Seasonal variation of lead concentration in urban area in poplar leaves, is discussed as part of the more general problem of the interactions of gaseous and nongaseous air pollutants with terrestrial vegetation. 相似文献
199.
突发事件应急演练自本世纪初开始在我国广泛开展,近年来在检验应急预案、完善应急准备、锻炼应急队伍、磨
合应急机制和应急科普宣教等方面发挥了重要作用。随着应急管理工作扎实推进,应急演练相关问题研究也逐渐受到专
家学者的重视。笔者以“准备—实施—评估”逻辑主线,系统总结了新世纪以来我国在四大类突发事件应急演练的准备
流程与实务、实施形式与方式、评估内容与方法等方面所取得主要成果,并结合自身实践提出加强演练规划管理、注重
演练过程评估和实现演练信息化的应急演练发展方向。 相似文献
200.
讨论了以FeSO4·7H2O和H2SO4为原料,以HNO3为催化剂通入空气氧化铁(Ⅱ)制备聚合硫酸铁的主要影响因素。实验表明:[SO42-]/[Fe]总=1.35~1.40为较合适的投料比例;HNO3的投料量约为原料FeSO4·7H2O投料的4%,反应温度为60~90℃,搅拌速度为400~600r/min,反应时间4h。反应后期pH基本不变;产品对活性大红溶液的净水处理结果较为满意,脱色率98.8%,COD的去除率为92%。 相似文献