中国地表水酸化敏感性的区划

地表水体的酸化与集水区的许多环境因子密切相关,如土壤对酸的缓冲能力、基岩中和酸沉降的能力以及土地利用方式等.其中,土壤的抗酸化能力是关键因素.因此可以根据集水区土壤、基岩和土地利用方式等信息来评估地表水在不同流量下发生酸化的可能性.本研究成功地应用已有资料和数据得到了我国地表水对酸沉降的敏感性等级,并绘制了地表水酸化敏感性区划图.结果表明,我国大部分地表水对酸化并不敏感.极易酸化和较易酸化的地表水主要分布在东北的北部地区,占所有国土面积的2.67%,是该地区强酸性漂灰土、酸性母岩和针叶林植被共同作用的结果.对酸化敏感性为中级和低级,即不易酸化的地表水主要分布在东北暗棕壤地区和南方富铝土区域,占所有国土面积的15.2%.其余82.11%国土面积上的地表水对酸化不敏感,完全不可能发生酸化.北方地区主要是由于土壤的强缓冲能力,而在南方,石灰质土壤以及耕作农田的广泛分布是最重要因素.南方重酸雨区由于土壤对酸化并不很敏感,因此在短期内不会出现大面积水体酸化现象.由于东北近年来频频出现酸雨,因此东北的酸沉降必须及早防治,以免出现大面积酸化水体.     

环境模型参数识别与不确定性分析

在对水文模型实例的参数不确定性分析基础上,分别采用传统灵敏度分析方法、HSY算法、线性回归等方法对模型参数特性进行了识别与比较研究.结果表明参数优化算法与传统灵敏度分析方法不能解释模型结构复杂性特征,采用不确定性分析方法对环境模型参数进行识别提供了深入分析与理解模型系统的有效途径.     

急倾斜上保护层开采保护效果的参数敏感度研究

为对急倾斜上保护层开采过程中,保护层开采多参数同时变化时的保护效果变化规律进行量化研究,将被保护层膨胀变形曲线的形态参数作为保护效果考察指标,基于可旋转CCD试验方案进行有限元计算,建立了保护层开采保护效果的响应面模型,得到了不同保护效果指标受多个保护层开采参数变异影响的敏感度。通过对急倾斜上保护层开采实例进行敏感度分析得到:范围相关保护效果指标受保护层开采参数变异影响的敏感度最高,位置相关保护效果指标敏感度次之,卸压程度相关保护效果指标敏感度最小。范围相关保护效果指标中,上部卸压角受侧压系数变异影响最敏感,敏感度为1.70;下部卸压角受层间距变异影响最敏感,敏感度为1.02;倾向保护范围长度受层间距变异影响最敏感,敏感度为-1.89。     

Using Modeling to Improve Monitoring of Structured Populations: Are We Collecting the Right Data?

Abstract:  Population monitoring is central to most demographic studies and conservation efforts, but it may not always be directed at the most appropriate life stage. We used stochastic simulation modeling to evaluate the effectiveness of a monitoring program for a well-studied population of Eastern Imperial Eagles ( Aquila heliaca ) in Kazakhstan. Specifically, we asked whether the most appropriate data were being collected to understand system state and population dynamics. Our models were parameterized with data collected over the course of 25 years of study of this population. We used the models to conduct simulation experiments to evaluate relationships between monitored or potentially monitored parameters and the demographic variables of interest—population size ( N ) and population growth (λ). Static analyses showed that traditional territory-based monitoring was a poor indicator of eagle population size and growth and that monitoring survivorship would provide more information about these parameters. Nevertheless, these same traditionally monitored territory-based parameters had greater power to detect long-term changes in population size than did survivorship or population structure. Regardless of the taxa considered, threats can have immediate impacts on population size and growth or longer-term impacts on population dynamics. Prudently designed monitoring programs for any species will detect the demographic effects of both types of threats.     

Artificial neural network modeling of caste odor discrimination based on cuticular hydrocarbons in termites

Summary. Individuals in an insect colony need to identify one another according to caste. Nothing is known about the sensory process allowing nestmates to discriminate minute variations in the cuticular hydrocarbon mixture. The purpose of this study was to attempt to model caste odors discrimination in four species of Reticulitermes termites for the first time by a non-linear mathematical approach using an "artificial neural network" (ANN). Several rounds of testing were carried out using 1 – the whole hydrocarbon mixtures 2 – mixtures containing the hydrocarbons selected by principal component analysis (PCA) as the most implicated in caste discrimination. Discrimination between worker and soldier castes was tested in all four species. For two species we tested discrimination of four castes (workers, soldiers, nymphs, neotenics). To test cuticular pattern similarity in two sibling species (R. santonensis and R. flavipes), we performed two experiments using one species for training and the other for query. Using whole hydrocarbons mixtures, worker/soldier discrimination was always successful in all species. Network performance decreased with the number of hydrocarbons used as inputs. Four-caste discrimination was less successful. In the experiment with the sibling species, the ANN was able to distinguish soldiers but not workers. The results of this study suggest that non-linear mathematical analysis is a good tool for classification of castes based on cuticular hydrocarbon mixture. In addition this study confirms that hydrocarbon mixtures observed are real chemical entities and constitute a true chemical signature or odor. Whole mixtures are not always necessary for discrimination. Received 23 July 1998; accepted 9 October 1998.     

Window Sensitivity Functions for Line Transect Sampling

L and width 2w, then by a selection of viewing window is meant a choice of w, with the intent being to search for optimal viewing windows, with the goal in mind of improving variances of estimators of population density, reducing sampling effort, while maintaining the property of unbiasedness. The notions of increasing window sensitivity (IWS) and decreasing window sensitivity (DWS) are introduced, and a method of deriving confidence intervals is discussed.     

Comparing aquatic risk assessment methods for the photosynthesis-inhibiting herbicides metribuzin and metamitron

Three different risk assessment procedures are described that aim to protect freshwater habitats from risks of the photosynthesis-inhibiting herbicides metribuzin and metamitron. These procedures are (1) the first-tier approach, based on standard toxicity tests and the application of an assessment factor, (2) the Species Sensitivity Distribution (SSD) approach, based on laboratory tests with a wider array of species and the application of a statistical model to calculate the HCx (the Hazardous Concentration for x% of the species), and (3) the model ecosystem approach, based on the evaluation of treatment-related effects in field enclosures. A comparison of the risk assessment procedures reveals that the first-tier approach is the most conservative for metamitron and metribuzin, and that HC5 values (and even HC10 values) based on acute EC50 values of algae and aquatic vascular plants may be used to derive maximum permissible concentrations for single applications. For both compounds these HC5 values were very similar to the ecological threshold concentrations in the enclosure studies. In contrast to model ecosystem experiments, however, HCx values based on lab toxicity tests do not provide information on the recovery potential of sensitive endpoints and on indirect effects, which may be important for regulatory decision-making. In the enclosure study, indirect effects of metribuzin on invertebrate populations were observed at an exposure concentration that was approximately 20 times lower than the corresponding HC5 value based on lab toxicity data for aquatic invertebrates.     

氧化镁FGD脱硫过程的建模及其应用

氧化镁烟气脱硫是以氧化镁为脱硫反应剂的一种湿法烟气脱硫技术，目前国内外应用甚少，但开发前景广阔。以实验室小试为基础，从气液传质入手，利用双膜理论建立脱硫过程的数学模型，从而对中试脱硫效率进行预测并进行参数敏感性分析。结果表明，模型预测的脱硫效率与实际脱硫效率有很高的吻合度，其计算参数能反映出实际运行参数对脱硫效率的影响，对实际工况中操作条件的变更以及运行参数的调试有很高的指导意义。     

城市污水处理厂除臭技术

介绍了城市污水处理厂臭气来源、成分及产量。针对目前国内外除臭技术的研究和发展情况，分析了污水处理厂的各种物理、化学和生物除臭方法的技术原理、优缺点和应用现状。结合日本城市污水处理厂的运行实际，重点介绍了一种不产生臭气的新技术——腐殖活性污泥法的工艺流程、特点及其应用现状。     

低温等离子体治理H2S污染的实验研究

低温等离子体技术是一种高效、快速的污染消除技术，国内外都在对其进行广泛而深入的研究。采用脉冲电晕放电等离子体对空气中的硫化氢进行降解研究，探索了、脉冲峰压、脉冲频率、气体流量以及气体初始浓度对净化效果的影响，气体浓度由气相色谱仪测定。结果表明，脉冲电晕放电可以有效消除硫化氢污染，净化率随脉冲峰压和脉冲频率的增加而提高，随气体初始浓度和流量的增加而下降，且在初始浓度360mg／m^2、流量1200mL／min、脉冲峰压30kV、脉冲频率80Hz的条件下，处理后的气体中已检测不到H2S，根据色谱检测限（0．29mg／m^3）计算出的净化率≥99．92％。采用离子色谱对产物进行了定性分析，发现H2S经放电处理后主要产物为SO2和SO3。