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1.
农业生态经济系统生态效益综合评价方法探讨   总被引:5,自引:0,他引:5  
根据系统思想和生态学原理,探讨了农业生态经济系统的生态效益和功能的定量评价方法,并给出了相应的计算规则,同时还阐述了这一方法在广西壮族自治区来宾县的实际应用。  相似文献   

2.
人居环境的可控性   总被引:2,自引:0,他引:2  
针对人居环境的复杂性、动态性以及纷繁复杂的影响因素,试图以系统论的观点考查人居环境的可能性发展空间,提出了人居环境大系统的观点,阐述了人工系统、人文系统和自然系统的构成和关系,提出并论述了通过结构优化、功能模拟、反馈控制等方法促使人居环境系统得到合理发展的观点。  相似文献   

3.
运用生态经济学原理,在对汉王乡生态经济系统进行现状分析、模型诊断和预测的基础上利用多目标规划方法,提出了该生态经济系统1995年和2000年生态农业建设规划方案。结果表明,按此方案实施后,系统现有资源将会得到持续、合理的利用,经济、生态和社会效益将显著提高。  相似文献   

4.
生态影响评价中生境评价方法   总被引:23,自引:0,他引:23  
生态影响评价是环境影响评价的重要分支,生境评价方法是生态影响证件 主要方法。美国是较早开展生态影响评价的国家,发展了一批生境评价方法。本文系统介绍了美国两种最常用的生境评价方法-生境评价系统和生境评价程序,并简要对比介绍其它方法,为我国开展生态影响评价提供一定理论参考。  相似文献   

5.
运用生态经济学原理,在对汉王乡生态经济系统进行现状分析、模型诊断和预测的基础上利用多目标规划方法,提出了该生态经济系统1995年和2000年生态农业建设规划方案,结果表明,按此方案实施后,系统现有资源将会得到持续,合理的利用、、生态和社会效益将显著提高。  相似文献   

6.
一个农业系统生物能量转换的动态模拟   总被引:2,自引:0,他引:2  
本文用系统动力学的方法,从生物能量转移的角度,探讨了一个村庄农业系统结构与功能的关系,首先在调查和实验的基础上确定系统内部各因子之间的动态关系。进而构造一组数学模型来描述系统的变化。然后在计算机上做模拟实验,结果表明,对我们所讨论的系统,控制人口增长,提高燃料热效率,减少生物能做燃料的比重,调整作物结构,发展畜牧业,就可以提高作物产量,改进系统的生态和经济效益。  相似文献   

7.
本文对引进的天津水质自动监测系统在运行期间,通讯系统出现的故障作了全面的剖析研究,并提出了解决这些问题的方法。  相似文献   

8.
简要介绍了土地定级信息系统和土地估价信息系统的软件和硬件配置、系统的结构与功能,并以通州市为例,阐述了土地定级信息系统的基本算法和模型参数的确定方法。  相似文献   

9.
土壤遥感分类识别专家系统的结构设计   总被引:3,自引:0,他引:3  
付炜 《生态环境》2004,13(1):63-68,73
介绍了土壤遥感分类识别专家系统的设计原理与实现方法,阐述了土壤遥感分类识别专家系统的土壤分类决策判断树的构造原理,讨论了土壤遥感分类识别专家知识表示的基本原则和系统知识库中专家知识的组织方式,以及专家系统推理机的设计原理和推理规则的构建方法。系统采用压缩编码方式存储地学专题图形和遥感图像数据,具有数据与图像的存储更新、查询检索、分析处理、特征提取和信息输出等功能。该系统可以对遥感图像进行土壤类型的分类识别,并对分类精度进行监测与评价。用该系统对新疆天山北麓阜康试验区的土壤分类识别进行了试验研究,并对试验结果进行了讨论与评价。  相似文献   

10.
多位点酶电泳在黄芪根瘤菌分类中的应用   总被引:2,自引:0,他引:2  
报导了分析根瘤菌各种多位点酶的电泳缓冲系统和染色方法,并对黄芪根瘤菌进行了分类研究,结果表明:采用多位点酶电泳图谱进行聚类可得到与数值分类基本一致的结果,证实这是一种行之有效、简便快速的分类方法.  相似文献   

11.
TEOM法与实验室称重法监测大气中TSP的对比研究   总被引:3,自引:0,他引:3  
孙杰  林楚雄  张俊 《环境化学》2001,20(1):86-92
用数理统计的方法计算出TEOM法与称重法监测结果的偏差,用F检验法检验TEOM法与称重法监测结果之间的致性,用r检测法检验TEOM法与称重法监测结果之间的相关性,用t检验法检验TEOM法与称重法监测结果之间的差异,通过对比研究,找出TEOM法与称重法之间的相互关系和规律。  相似文献   

12.
采用物料平衡法、置换成本法、条件价值评估法(CVM)和COD价格法对池塘养殖环境成本进行评估。结果显示,基于4种评估方法估算得到的池塘养殖环境成本由大到小依次为置换成本法(4 400元.a-1.hm-2)、COD价格法(4 191.99元.a-1.hm-2)、物料平衡法(3 925.76元.a-1.hm-2)和CVM法(2 007.8元.a-1.hm-2),认为在不考虑时间和经济成本的前提下,基于COD价格法测算得到的结果可能最接近于环境成本的真实值。采用4种评估方法测得的环境成本占常规鱼类养殖经济总收益的6%~14%,表明采取相关措施防治水产养殖环境污染很有必要。  相似文献   

13.
铁氧体法处理重金属废水的实践与发展   总被引:1,自引:0,他引:1  
本文介绍铁氧体法处理重金属废水的工艺流程、技术关键及其特征,并梗概介绍了铁氧体法的新发展:GT—铁氧体法.  相似文献   

14.
Emergy studies have suffered criticism due to the lack of uncertainty analysis and this shortcoming may have directly hindered the wider application and acceptance of this methodology. Recently, to fill this gap, the sources of uncertainty in emergy analysis were described and analytical and stochastic methods were put forward to estimate the uncertainty in unit emergy values (UEVs). However, the most common method used to determine UEVs is the emergy table-form model, and only a stochastic method (i.e., the Monte Carlo method) was provided to estimate the uncertainty of values calculated in this way. To simplify the determination of uncertainties in emergy analysis using table-form calculations, we introduced two analytical methods provided by the Guide to the Expression of Uncertainty in Measurement (GUM), i.e., the Variance method and the Taylor method, to estimate the uncertainty of emergy table-form calculations for two different types of data, and compared them with the stochastic method in two case studies. The results showed that, when replicate data are available at the system level, i.e., the same data on inputs and output are measured repeatedly in several independent systems, the Variance method is the simplest and most reliable method for determining the uncertainty of the model output, since it considers the underlying covariance of the inputs and requires no assumptions about the probability distributions of the inputs. However, when replicate data are only available at the subsystem level, i.e., repeat samples are measured on subsystems without specific correspondence between an output and a certain suite of inputs, the Taylor method will be a better option for calculating uncertainty, since it requires less information and is easier to understand and perform than the Monte Carlo method.  相似文献   

15.
We present a new method for estimating a distribution of dispersal displacements (a dispersal kernel) from mark-recapture data. One conventional method of calculating the dispersal kernel assumes that the distribution of displacements are Gaussian (e.g. resulting from a diffusion process) and that individuals remain within sampled areas. The first assumption prohibits an analysis of dispersal data that do not exhibit the Gaussian distribution (a common situation); the second assumption leads to underestimation of dispersal distance because individuals that disperse outside of sampling areas are never recaptured. Our method eliminates these two assumptions. In addition, the method can also accommodate mortality during a sampling period. This new method uses integrodifference equations to express the probability of spatial mark-recapture data; associated dispersal, survival, and recapture parameters are then estimated using a maximum likelihood method. We examined the accuracy of the estimators by applying the method to simulated data sets. Our method suggests designs for future mark-recapture experiments. Received: January 2004 / Revised: July 2005  相似文献   

16.
适宜的生态需水量是保障河道生态系统健康的重要因素,合理地计算生态需水量对河道生态系统评估具有现实意义。以鄂北地区典型浅丘河道——水河为例,基于Qp法(不同频率最枯月平均值法)、频率曲线法、最小月平均流量法、Tennant法及生物习性法5种方法的生态流量计算结果,探讨了各方法计算结果的合理性与适用性。结果表明:由于上下游河道水文条件差异性,上游断面采用生物习性法能较好地拟合河道水文节律变化和水质波动;同理,下游断面采用频率曲线法更加匹配下游河道水文、水质情况。因此,在河道上、下游断面分别采用生物习性法、频率曲线法计算得到适宜生态需水量为0.21 m^3/s、2.02 m^3/s。  相似文献   

17.
王连生  张正 《环境化学》1993,12(2):151-154
本文采用产生柱法测定取代苯乙酮类有机物的水溶解度和正辛醇-水分配系数,与静态法和振荡法测定的水溶解度、摇瓶法测定的正辛醇-水分配系数相比较,证明此方法是可行的,并和分子连接性指数呈良好的相关性。  相似文献   

18.
• An integrated method, called PHDVPSS, was proposed for treating DCS. • The PHDVPSS method showed superior performance compared to conventional method. • Using the method, water content (%) of DCS decreased from 300 to<150 in 3 days. • The 56-day UCS from this method is 12‒17 times higher than conventional method. • Relative to PC, GGBS-MgO binder yielded greater reduction in the leachability. To more efficiently treat the dredged contaminated sediment (DCS) with a high water content, this study proposes an integrated method (called PHDVPSS) that uses the solidifying/stabilizing (S/S) agents and prefabricated horizontal drain (PHD) assisted by vacuum pressure (VP). Using this method, dewatering and solidification/stabilization can be carried out simultaneously such that the treatment time can be significantly shortened and the treatment efficacy can be significantly improved. A series of model tests was conducted to investigate the effectiveness of the proposed method. Experimental results indicated that the proposed PHDVPSS method showed superior performance compared to the conventional S/S method that uses Portland cement (PC) directly without prior dewatering. The 56-day unconfined compressive strength of DCS treated by the proposed method with GGBS-MgO as the binder is 12‒17 times higher than that by the conventional S/S method. DCS treated by the PHDVPSS method exhibited continuous decrease in leaching concentration of Zn with increasing curing age. The reduction of Zn leachability is more obvious when using GGBS-MgO as the binder than when using PC, because GGBS-MgO increased the residual fraction and decreased the acid soluble fraction of Zn. The microstructure analysis reveals the formation of hydrotalcite in GGBS-MgO binder, which resulted in higher mechanical strength and higher Zn stabilization efficiency.  相似文献   

19.
A benchmark dose (BMD) for quantitative responses is a lower confidence limit (LCL) on the effective dose corresponding to a specified risk level r. A commonly adopted method for calculating the BMD is to obtain a pointwise upper confidence curve U(d) on the risk function and then invert this relationship by solving the equation U(d)=r. The solution d is taken to be the BMD. Sciullo et al. (2000) have shown that the coverage achieved by this inversion method is at least as great as the coverage achieved by U (·) but that there is otherwise no general relationship between the two coverage probabilities. The present paper develops a method for direct calculation of the BMD based on the asymptotic distribution of the likelihood ratio statistic. It is further shown that the direct method and the inversion method are equivalent when U (·) is also based on the likelihood ratio. Since the direct method is known to be asymptotically correct, it follows that the LR-based inversion method is also asymptotically correct. However, the direct method is computationally faster and easier to program. Finally, some simulation studies are conducted to assess the small sample coverage probabilities of the direct method when responses follow either a normal or a gamma distribution.  相似文献   

20.
基于水文学方法的珠江流域生态流量研究   总被引:1,自引:0,他引:1  
张强  崔瑛  陈永勤 《生态环境》2010,19(8):1828-1837
珠江流域水资源丰富,但由于水体污染等原因,水质性缺水问题较为突出,区域水环境、水生态以及水安全等成为急需解决的重要科学问题。开展生态流量研究对于评价地表水文过程演变对区域水环境与水生态的影响具有重要理论意义,并为区域水资源优化配置和可持续开发利用提供科学依据。基于此,运用各种"水文学"方法(包括最小月平均流量法、改进的7Q10法、NGPRP法、逐月最小生态径流计算法和逐月频率计算法)对珠江流域11个主要水文控制站点的实测月径流量做了全面而系统的研究,分析珠江流域生态径流过程,并通过与Tennant法对比分析,选择逐月最小生态径流计算法和逐月频率计算法分别计算了各水文控制站的最小生态径流量和适宜生态径流量,除个别站点外,其评价结果分别处于Tennant法"中"和"最佳"的等级。对于逐月频率计算法中保证率的选取方法,研究表明各月径流系列均取50%最适合珠江流域。研究同时为仅利用水文资料中的多年逐月径流数据来确定生态需水提供了一种新的研究思路。  相似文献   

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