Comparison of Spatial Methods for the Assessment of Planktonic Patches

Planktonic patches are defined as areas where the abundance of plankters is above a threshold value τ. The estimation of patch size and shape can be approached using spatial statistical tools, using truncated random fields or indicator random fields as classifiers. In all cases there is the risk of false positive and false negative errors. In this paper we present the results of a comparative study on the performance of four commonly used methods: conditional simulation and kriging, both in the original measurement units of the data and under an indicator transform. We used a misclassification cost function to compare the four methods. Our results show that conditional simulation in the original measurement units attains the lowest misclassification cost. We also illustrate how the point at which this minimum is attained can be used to chose an optimal cut-off value for binary classification. Received: December 2003 / Revised: June 2005     

Subgrid-Scale Modeling of Reacting Scalar Fluxes in Large-Eddy Simulations of Atmospheric Boundary Layers

In large-eddy simulations of atmospheric boundary layer turbulence, the lumped coefficient in the eddy-diffusion subgrid-scale (SGS) model is known to depend on scale for the case of inert scalars. This scale dependence is predominant near the surface. In this paper, a scale-dependent dynamic SGS model for the turbulent transport of reacting scalars is implemented in large-eddy simulations of a neutral boundary layer. Since the model coefficient is computed dynamically from the dynamics of the resolved scales, the simulations are free from any parameter tuning. A set of chemical cases representative of various turbulent reacting flow regimes is examined. The reactants are involved in a first-order reaction and are injected in the atmospheric boundary layer with a constant and uniform surface flux. Emphasis is placed on studying the combined effects of resolution and chemical regime on the performance of the SGS model. Simulations with the scale-dependent dynamic model yield the expected trends of the coefficients as function of resolution, position in the flow and chemical regime, leading to resolution-independent turbulent reactant fluxes.     

用平板双分子层脂膜模拟研究锌离子跨细胞膜的传递过程

制备了氧化胆固醇-卵磷脂（脑磷脂）平板双分子层脂膜，研究了膜配方对双分子层脂膜的稳定性和离子传递性能的影响，得到了最佳制膜工艺，并建立了锌离子跨卵（脑）磷脂膜的吸附-扩散模型，其计算值与实验值基本吻合．     

工业废水中微量镍的流动注射光度分析

采用流动注射分析技术,在柠檬酸,碘存在的氨性介质中,以丁二酮肟为显色剂,应用光度自动分析方法,测定废水中微量镍,检出限为0.3mg·l~(-1);线性范围为0.3～10mg·l~(-1);相对标准偏差<1％。     

Modelling the meteorological influence onthe yellowing of spring wheat leaves

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高层建筑承受纵向地震波时的安全核算构想

高层建筑可预期的灾变非至一端，这里仅探讨高层建筑的抗震性能问题。地震过程中楼体受到的是地震波和自身固有频率的共同作用，此时楼体是一个多维动态系统，其应力状态比传统方法所描述的力学模型要复杂行多。本文应用ANSYS三维仿真有限元软件，采用单点响应谱的方法，对楼体在纵向地震波作用下的应力状态和变形情况进行了分析。对楼体构件单元型式的选择、网格密度的确定、有限元模型的建立等也提出了自己的见解。在后处理中，用列表和图形的方式显示了楼体的位移和应用状态。     

板材成形模拟的研究和应用

介绍了板材成形数值模拟技术的研究和应用在国内外发展的概况 ,并从基本算法、单元模型和网格划分、材料模型、接触摩擦、起皱问题、破裂问题和回弹计算等方面介绍了弹塑性有限元的基本原理、关键技术和主要难点 ,结合在工厂实际生产中的使用情况和存在的问题 ,展望了板材数值模拟技术今后的发展方向     

活性污泥法简化数学模型的研究与进展

介绍几种简化数学模型 (如ROM、SPM、SLM等 )的结构与特点。模型的验证结果表明 ,简化模型能够较好的模拟系统的运行 ,产生较为准确的模拟结果     

反向方法在板料成形工艺设计中的应用研究

利用结合拉延筋计算的反向方法的数值模拟技术，研究了其在板料成形工艺设计中的应用，提出了进行初期工艺设计评估的新方法。同时对后轮毂鼓包内板件毛坯进行工艺设计，与福特公司的MTLFRM软件的对比结果表明设计的工艺是合理的，也表明该方法可以适用于大型覆盖件的工艺设计。     

废水处理仿真基准模型BSM1简介

文章比较详细地介绍了欧盟科学技术合作组织所研究的项目中，一个关于水处理的仿真基准模型（BSM1）。该模型建立在活性污泥法处理废水的基础之上，所选择的建模对象是一种简单常见的生物反应器和二次沉淀池组成的活性污泥水处理系统，致力于C、N的去除。应用该模型可以很方便地进行水处理控制方案之间的效果比较，对于世界各地的水处理研究机构之间的沟通有很大的帮助。文章结尾部分还对该模型存在的缺陷和今后的发展方向做了分析。