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571.
以PTA生产尾气为实验体系,讨论了在活性炭对有机气体动态吸附过程中,有机气体初始浓度的三种测定方法,即气相色谱法、吸附称量法和气体方程计算法。结果得出,吸附称量法误差最小,其次是气体方程计算法,误差最大的是气相色谱法。 相似文献
572.
573.
介绍了常用统计量矩阵的基础知识,以及日常统计工作中常用的参数进行矩阵化的方法。 相似文献
574.
575.
Traditionally, uncertainty in parameters are represented as probabilistic distributions and incorporated into groundwater flow and contaminant transport models. With the advent of newer uncertainty theories, it is now understood that stochastic methods cannot properly represent non random uncertainties. In the groundwater flow and contaminant transport equations, uncertainty in some parameters may be random, whereas those of others may be non random. The objective of this paper is to develop a fuzzy-stochastic partial differential equation (FSPDE) model to simulate conditions where both random and non random uncertainties are involved in groundwater flow and solute transport. Three potential solution techniques namely, (a) transforming a probability distribution to a possibility distribution (Method I) then a FSPDE becomes a fuzzy partial differential equation (FPDE), (b) transforming a possibility distribution to a probability distribution (Method II) and then a FSPDE becomes a stochastic partial differential equation (SPDE), and (c) the combination of Monte Carlo methods and FPDE solution techniques (Method III) are proposed and compared. The effects of these three methods on the predictive results are investigated by using two case studies. The results show that the predictions obtained from Method II is a specific case of that got from Method I. When an exact probabilistic result is needed, Method II is suggested. As the loss or gain of information during a probability–possibility (or vice versa) transformation cannot be quantified, their influences on the predictive results is not known. Thus, Method III should probably be preferred for risk assessments. 相似文献
576.
Structural equation-based latent growth curve modeling of watershed attribute-regulated stream sensitivity to reduced acidic deposition 总被引:2,自引:0,他引:2
Little information is available about the effects of watershed attributes on long-term stream chemical responses to reduced acidic deposition. Long-term chemical data (1980-2006) for 21 stream sites from the Appalachian Mountain region and data of 8 watershed attributes of the corresponding watersheds were analyzed to study such effects. Latent growth curve modeling (LGM), a structural equation modeling (SEM) approach, was conducted to quantify stream sensitivity to reduced acidic deposition in the region, and to model the initial chemical conditions (intercepts) and changing rates (slopes) in three time periods: 1980s, 1990s, and 2000s. The modeled chemical trends were generally consistent with those trends which were detected by trend analyses in a previous study. Watershed attributes including area, mean elevation, percentage of developed land, percentage of grassland, percentages of shale and sandstone, percentage of barren land, and percentage of soil type Gilpin-Upshur-Vandalia (GUV) were found to affect stream sensitivity to the reduced acidic deposition with their importance in the respective order. The stream sensitivity in turn regulated streams’ chemical initial conditions and their changing rates in the studied watersheds. This innovative application of LGM for modeling long-term chemical trends advanced our understanding of the role of watershed attributes in regulating streams’ responses to reduced acidic deposition. This approach can be applied for evaluating streams’ responses to acidic deposition in other regions and, more broadly, for studying causal effects on long-term behaviors in other ecological and environmental science subjects. 相似文献
577.
蛋白核小球藻与邻苯二甲酸二甲酯的相互作用研究 总被引:6,自引:0,他引:6
本文运用评价化学品对藻类毒的标准方法,得出邻苯二甲酸二甲酯对蛋白核小球藻的96h EC50为313mg/l。实验结果表明,蛋白核小球藻对邻苯二甲酸二甲酯有明显的富集与降解作用,富集量24h最大达15.36mg/g,此后随时间的延长而逐步降低。5d降解率为66.8%。在对实验结果分析的基础上,提出了蛋白核小球藻对邻苯二甲酸二甲酯的二级降解反应动力学方程为-dc/dt=KNr,用此方程计算邻苯二甲酸二 相似文献
578.
The aim of this paper is to presents a progress report on how a subnational jurisdiction, the Australian state of Victoria, is attempting to implement regional governance for sustainability through its catchment planning framework. The paper examines the lessons learnt from a best practice approach to the implementation of network governance to see whether there are actions that can be taken to improve regional governance for sustainability in Victoria. The authors argue that Victoria is implementing a network governance approach to natural resource management (NRM) as a significant component of sustainability and that this has certain advantages. In particular the emergence of Regional Catchment Strategies developed by the State's ten statutory Catchment Management Authorities as 'regional sustainability blueprints' is bringing a significant level of maturity to the state's governance framework. Furthermore the state is currently working to complete its governance for sustainability through new statewide integrating frameworks—an Environmental Sustainability Framework as well as a statewide Catchment Management and Investment Framework. The paper concludes that taking a network governance approach could have transformative potential but there are significant challenges ahead: the complex task of aligning of national, state, catchment and local government strategies through an outcomes focus; the scarcity of mechanisms and tools to assist in translation of strategies into integrated investment priorities; gaps in knowledge and understanding of natural resource management problems; limitations in the capacity of regional and local bodies, including local government; and getting the policy tools right within the framework. However, as the best practice examples illustrate, taking a gradual approach to the development of the institutions—building on successive wins in capacity—is the best and only way to proceed. 相似文献
579.
预测结垢趋势是污水回注中的一项重要工作,通常都要计算离子强度,而离子强度的计算量很大,因此提出了一种替代的估算方法———矿化度法。由于矿化度的测定较为容易,计算简便,建立矿化度和离子强度之间的一元线性关系,使计算得以大大简化。通过中原油田的实例详细说明了一元线性关系的建立方法及判定是否适用的标准,并提出:不同水质情况应分别建立各自的一元线性回归方程。 相似文献
580.
郎庆成 《再生资源与循环经济》2011,4(10):35-37
针对海波定影液体系中还原铁粉置换还原银,并生成致密产物层的液、固两相反应,建立了更一般情形的动力学方程,并给出其精确解。方程中Piling因子非限定,且定影液银浓度和还原铁粉几何面积随时间变化。应用此动力学方程处理液、固两相反应,比以往研究中的动力学方程更加准确、合理。该方程在原则上也适用于气、固两相反应。 相似文献