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91.
采用储量较大的黑龙江省嫩江天然斜发沸石,对其脱除NH_3-N的能力、预处理及洗脱再生方法、交换平衡、交换动力学等进行系统的研究,并对沸石床层的交换过程进行数学模型计算。 相似文献
92.
应用Al-Ferron法于悬浮体系中聚合铝的形态分布表征,对其中的主要影响因素进行探讨,就不同碱化度聚合铝的形态分析进行实例研究.结果表明,混合方式对Al-Feron法的应用具有一定的影响作用.比色管混合测得Ala为21.54%,低于磁力搅拌方式结果(24.52%,25.22%,25.06%).应用磁力搅拌方式可以获取较好的重复性与更多初期反应信息.颗粒物的存在对反应的影响主要取决于其浓度与粒度分布,成一定线性关系,可以从中加以扣除.在本实验范围内因其溶解所产生的影响可以忽略不计.对多个碱化度聚合铝的实例研究表明,Al-Feron法完全适用于颗粒物悬浮体系中的形态分布表征 相似文献
93.
In this paper,the eco-environmental susceptibility of Shangyi County,Northern Hebei Province of China has been calculated by using the weighted-addition method based on expert's giving a mark to each influencing factor according to their knowledge on the influence of all the factors on eco-environmental susceptibility.The eco-environmental classification and distribution map were reached based on the above results,its difference is mainly result from the physical conditions and human activity,however the value of eco-environmental susceptibility is only a relative index which can not completely reflect the quality of eco-environment.This work provided a basis for controlling the further development of desertification. 相似文献
94.
95.
把系统聚类分析(简称HCA-hierachical cluster analysis) 和主成分分析方法(简称PCA-Principal Component Analysis)有机结合,从给定的"样品-指标"数据矩阵出发,利用HCA科学判定区域环境污染的类型,然后根据不同的类型利用PCA方法确定首要污染因子,针对首要污染因子,对各个污染途径进行评估,计算出各途径的污染分担率,从而确定区域污染成因.并对其原理、计算方法、特点作出分析和讨论,同时以某城镇水环境为例进行了计算示范.经证实该方法在确定区域环境污染成因,制定区域污染防治措施方面有重要的意义. 相似文献
96.
生态系统服务的核算方法 总被引:3,自引:0,他引:3
生态系统服务是指对人类生存及生活质量有贡献的生态系统产品和生态系统功能 ,包括由自然生态过程产生并维持的环境和资源条件。目前已有的生态系统服务核算方法可以分为市场价值法、替代市场法和假想市场法。 相似文献
97.
IntroductionTheuseofchemicals,includingpesticides,hasbecomeanintegralandeconomicallyessentialpartofmodernagriculture.Pesticide?.. 相似文献
98.
A baseline for a project consists of estimates of annual emissions of greenhouse gases (GHG) for a given time period without implementing the project. A general three-step process for determining the baseline is suggested. The emission reduction of the project is given by the difference between the baseline and the monitored annual emissions. A preferred method, direct measurement of the emission reduction, is possible for some types of projects. Methods for estimating the annual baseline emissions are not necessary for the latter category, and a definition of this project category is suggested. IPCC Guidelines for National GHG Inventories categorise the emission sources so that only direct emissions from consumption of fuel and feedstock are calculated. There are thus no emission factors for indirect emissions (e.g. electricity consumption or km transported) or emission factors that depend on technology only, independent of consumption of fuel and feedstock. Technology-dependent emission factors may thus need to be developed for estimating indirect emissions and multi-project baselines. Consistency should be sought with the IPCC Guidelines when estimating annual baseline emissions and in monitoring project emissions to ensure comparability with the National Inventories. 相似文献
99.
100.
V. Sivakumar V. Ravi Verma P.G. Rao G. Swaminathan 《Journal of Cleaner Production》2007,15(18):1813-1818
Focus on eco-friendly processing techniques makes vegetable tanning a viable option in leather processing and establishes the subsequent need for the more efficient methods of extraction in tannin manufacture. Application of ultrasound has been tried in the extraction of tannins from myrobalan nuts in order to improve the extraction efficiency, to perform the extraction under milder process conditions and to reduce the process time. The influence of process parameters such as ultrasonic output power, time and temperature has been studied. Scale-up trials and the use of ultrasound in pulse mode have also been attempted. The results show that a three- to fivefold improvement is possible with ultrasonic output from 20 to 100 W. Extraction efficiency has been calculated from the maximum extractable materials from myrobalan nuts. Extraction efficiency is found to be 90% for ultrasound, 100 W without external heating as compared to 77% for control process at 70 °C for 4 h. Therefore, ultrasound could be employed even dispensing with provision for temperature controls. The use of ultrasound in pulse mode offered 70% extraction efficiency of continuous mode. Scale-up trials indicate that there exists an optimum ultrasonic output power depending on the amount of nuts used, to achieve better extraction efficiency. The effectiveness of ultrasonically extracted tannin solution has also been tested in the tanning process for its applicability. The degree of tanning efficacy has been assessed by shrinkage temperature measurement. The results indicate that ultrasonically extracted tannin solution is suitable for tanning process. Therefore, application of ultrasound in tannin extract manufacture is a viable option with added advantages. 相似文献