拟面积多波长数据线性双组合解析萘,1—萘酚和2—萘酚同步荧光光谱的研究

本文研究了Δλ（λｅｍ－λｅｘ）为１３０ｎｍ和ＰＨ１２．０条件下，萘、１－萘粉和２－萘酚混合物的同步荧光光谱，获三者同步荧光峰信息，且萘被完全分辨，另外，提出用拟面积多波长线性双组合计算解析重叠的１－萘酚和２－萘酚同步荧光光谱，解析结果的精密度、组份间浓度比范围均较多波长线性回归、双峰增配平和一阶导数解析混合物同步荧光光谱结果为优。     

关于广义拟duo-环的正则性

刻画了广义拟duo-环并主要得到以下几个结果：（1）R是广义左拟duo-环当且仅当且是MELQ的左极小Abel环．（2）设R是一个环,R是强正则环且仅当是广义左左拟duo的左GP-V-环．参7．     

微乳法制备W/O型Fe3O4磁流体及其清除水面浮油模拟研究

应用复合乳化剂和助表面活性剂制备出稳定的油包水(W／O)型微乳液,利用拟三元相图和体系电导随组成的变化,探明了一定条件下形成W／O型微乳液的最佳体系,进而利用W／O型微乳液作为“微反应器”合成Fe2O4磁流体,应用TEM对制备的磁流体进行了表征．初步模拟了用磁流体清除水面浮油的实验,获得令人满意的结果。     

基于合作博弈的流域水污染治理成本分摊研究

运用合作博弈理论,针对流域水污染治理的成本分摊问题构造成本分摊博弈,在传统的夏普利值解的基础上,提出运用新提出但更具有普适性的二项式半值解的概念.以长江流域三峡库区相邻的3个行政区域——忠县、万州、云阳作为研究对象,以化学需氧量作为水质指标,在考虑联盟结构的情况下,通过多重线性扩展方法进行求解.研究结果满足二项式半值特征函数要求具备的超可加性、集体理性和个体理性3个条件,流域水污染治理成本在3个地区间进行了公平合理的分摊,证明了该方法的有效性.     

高效液相色谱法同时测定水体中的四种酰胺类化合物

本文拟采用高效液相色谱法,以乙腈和水作为流动相,建立一种快速测定环境水体中甲酰胺、N,N-二甲基甲酰胺、N,N-二甲基乙酰胺和丙烯酰胺的方法.在5 min内即可完成环境水体4种典型的酰胺类化合物的测定,在0.5—1000 mg·L-1范围内均具有良好的线性.     

取代芳烃的生物降解性与结构相关性研究

采用量子化学MOPAC－AM1法计算了42种取代芳烃的生成热Hf、分子最高占有轨道能EHOMO、分子量MW、分子总表面积TSA及偶极矩μ。分别采用线性回归分析法和人工神经网络法对所研究化合物的生物降解性参数BOD进行QSBR研究。对训练组而言，线性方法和神经网络法的平均预测误差分别为15．9％和11．4％；而测试组化合物的平均百分误差分别为14．5％和13．0％。无论对于测试组还是训练组，神经网络法的预测都更精确。     

甲基对硫磷对三种拟除虫菊酯杀虫剂的光敏降解研究

本文以高压汞灯和自然阳光为光源，研究了甲基对硫磷对氧氰菊酯、溴氰菊酯和氰茂菊酯在玻片表面光致降解的影响。结果表明：甲基对硫磷与三种拟除虫菊酯农药混合照光处理后，可使拟除虫菊酯农药的光解速度加快。氯氰菊酯、氰戊菊酯和溴氰菊酯的光解半衰期，在高压汞灯下比其单独照光分别缩短１２．１８、８．４６和７．３３倍，在阳光下则分别缩短４．７３，２．６５，和４．４６倍。甲基对硫磷对三种拟除虫菊酯农药表现出显著的光敏     

8种拟除虫菊酯农药对稀有鲫的急性、亚慢性毒性研究

８种拟除虫菊酯对稀有鲫的急性毒性和其中２种拟除虫菊酯的亚慢性毒性研究结果表明：溴氰菊酯、高效氯氰菊酯、氯氰菊酯、甲氰菊酯、氰戊菊酯、二氯炔戊菊酯、胺菊酯、甲醚菊酯对稀有鲫均属剧毒,它们的ρ（９６ｈＬＣ５０）／μｇ·Ｌ－１分别为３．１６,３．２４,６．３１,７．２１,７．３５,３２．４５,９１．７５和８８２．６;甲氰菊酯、二氯炔戊菊酯对稀有鲫７ｄ亚慢性毒性的最低有影响浓度ρ（ＬＯＥＣ）和最高无影响浓度ρ（ＮＯＥＣ）分别为０．８８～０．４４μｇ／Ｌ,４．０～２．０μｇ／Ｌ,以ρ（９６ｈＬＣ５０）／μｇ·Ｌ－１为基准,２种拟除虫菊酯的安全系数均为０．０６～０．１２５．     

红壤有机无机复合状况及氮素形态分布与肥力的关系

不同肥力红壤有机无机复合状况及氮素形态分布的研究结果表明，土壤肥力水平提高，有机无机复合量增大．复合量与土壤有机质、全氮、碱解氮、速效磷和ＣＥＣ呈显著或极显著正相关，与速效钾、缓效钾的相关性不显著；复合度与上述肥力性状的相关性均不显著．因此，可以用复合量来评价肥力状况．红壤酸解性氮占全氮７７％－８６％；在酸解性氮中，各组分氮所占比例为氨基酸态氮＞酸解氨态氮＞酸解未鉴别态氮＞氨基糖态氮．氨基酸态氮占酸解性氮的比率为高肥力红壤大于低肥力红壤，且与土壤有机质、全氮、碱解氮、速效磷里显著正相关，也可作为衡量土壤肥力状况的指标之一．     

拟除虫菊酯在不同猝灭体系中的光化学降解

本文选择了具有抗氧作用或光屏蔽作用的六种物质，测定了它们在不同浓度配比，不同光照时间，不同充气条件下对这四种拟除虫菊光解稳定性的影响，结果表明，它们对拟除虫菊酯有不同程度的光稳定作用，光屏蔽型稳定对浓度的变化更为敏感，耗氧型稳定剂由于自身的消耗对光照时间，充氧条件为敏感，由此可见，不同的环境条件对拟除虫菊酯类农药的残留产生较大影响，同时，使用光稳剂将是一种增强拟除虫菊酯光稳定性，充分发挥杀虫作用的     

模拟酸雨下H+-Ca2+在红壤表面的动力学特征

研究模拟酸雨下H Ca2 在红壤表面的反应动力学吸附特征 ,结果表明 :Ca2 的吸附动力学能很好地用一级动力学方程、抛物线扩散方程和Elovich方程 (R2 >0 97)拟合 .随溶液酸度的增加 ,Ca2 的最大吸附量显著降低 ,Ca2 吸附反应速率控制步骤是离子在颗粒内的扩散 ,扩散速率常数随酸度的增加而下降 .酸溶液pH值为 4 5和 5 6时 ,有H 的释放 ,H 的表观释放量能用一级动力学方程和扩散方程拟合 ,Elovich方程不宜拟合pH 5 6酸处理的动力学数据 ;酸溶液pH值为 3 5和 2 5时 ,有H 的消耗 ,H 消耗总量看作表观消耗量 ,用一级动力学方程、Elovich方程和扩散方程进行拟合 .比较相关系数和标准误差的大小 ,除pH值为 2 5的酸处理用扩散方程拟合结果较差外 ,这 3种动力学模型进行拟合均得到较满意的结果     

Spreading of oil on water in the surface-tension regime

The third stage of oil spreading on water, in which surface-tension force promotes spreading against the resisting viscous effect, is investigated using a similarity solution in combination with an integral boundary-layer technique to solve the unidirectional oil-spreading dynamics problem in the last stage of spreading. The thin layer is assumed to be supplied by oil from a bulk boundary. Using a constitutive equation for oil-film surface tension versus oil-film thickness, analytical solutions near the bulk boundary and near the edge are developed. Using the asymptotic solutions to initiate integration, the differential equations for the oil thickness, oil velocity, and boundary-layer profiles are integrated starting from the leading edge and bulk boundary, which after matching provide a complete solution. The results for the spreading-law prefactors are found to differ by about 10 % from published theoretical results using the same constitutive equation. Using an empirical constitutive equation for oil-film surface tension versus distance from the bulk boundary leads to a spreading-law prefactor that is in excellent agreement with the published experimental result and published theoretical work providing and using the same empirical constitutive equation.     

Multiseasonal management of an agricultural pest. I: Development of the theory

A framework for analyzing the trade-off between economic yield from a crop and buildup of resistance to pesticide caused by repeated applications of pesticide is developed. The analysis begins with the case of age-independent pest dynamics, in which pests infest a field by arriving from an external pool. Initially, it is assumed that the pest genetics of interest are single locus, two allele, with resistance to pesticide dominant and susceptible pests more fit in the absence of spraying. The pesticide is applied only once during the season, with timing and intensity of the application as control variables. Interseasonal pest and crop dynamics are studied by solving appropriate ordinary differential equations. Intraseasonal pest dynamics are assumed to follow the Hardy-Weinberg formula. It is shown that the three class diploid model can be replaced by a two class haploid model with essentially no change in the results. A model based on partial differential equations is developed, for the case in which pest dynamics depend upon age, and it is shown that the partial differential equation model can be replaced by a pair of coupled ordinary differential equations. The main operational conclusion in this paper is that the timing of the application of pesticide can be used to control buildup of resistance and that the intensity of the application can be used to control the crop yield.     

Dressler’s theory for curved topography flows: iterative derivation,transcritical flow solutions and higher-order wave-type equations

The Dressler equations are a system of two non-linear partial differential equations for shallow fluid flows over curved topography. The theory originated from an asymptotic stretching method formulating the equations of motion in terrain-fitted curvilinear coordinates. Apparently, these equations failed to produce a transcritical flow profile changing from sub- to supercritical flow conditions. Further, wave-like motions over a flat bottom are excluded because the bed-normal velocity component is not accounted for. However, the theory was found relevant for several environmental flow problems including density currents over mountains and valleys, seepage flow in hillslope hydrology, the development of antidunes, the formation of geological deposits from hyper-concentrated flows, and shallow-water flow modeling in hydraulics. In this work, Dressler’s theory is developed in an alternative way by a systematic iteration of the stream and potential functions in terrain-fitted coordinates. The first iteration was found to be the former Dressler’s theory, whereas a second iteration of the governing equations results in velocity components generalizing Dressler’s theory to wave-like motion. Dressler’s first-order theory produces a transcritical flow solution over topography only if the total head is fixed by a minimum value of the specific energy at the transition point. However, the theory deviates from measurements under subcritical flow conditions, given that the bed-normal velocity component is significant. A second iteration to the velocity field was used to produce a second-order differential equation that resembles the cnoidal-wave theory. It accurately produces flow over an obstacle including the critical point and the minimum specific energy as part of the numerical solution. The new cnoidal-wave model compares well with the theory of a Cosserat surface for directed fluid sheets, whereas the Saint-Venant theory appears to be poor.     

Spatial effects and strategic behavior in a multiregional transboundary pollution dynamic game

We analyze a transboundary pollution differential game where pollution control is spatially distributed among a number of agents with predetermined spatial relationships. The analysis emphasizes, first, the effects of the different geographical relationships among decision makers; and second, the strategic behaviour of the agents. The dynamic game considers a pollution stock (the state variable) distributed among one large region divided in subregions which control their own emissions of pollutants. The emissions are also represented as distributed variables. The dynamics of the pollution stock is defined by a parabolic partial differential equation. We numerically characterize the feedback Nash equilibrium of a discrete-space model that still captures the spatial interactions among agents. We evaluate the impact of the strategic and spatially dynamic behaviour of the agents on the design of equilibrium environmental policies.     

A note on the development of the thermocline in temperate lakes

An exact solution has been obtained for a non-linear partial differential equation governing the vertical transport of heat in a lake. The equation, derived and analyzed numerically by Sundaram and Rehm (1971, 1973) is based on a balance between thermal buoyany forces and wind induced turbulence. The exact solution displays the qualitative features of the numerical solution and its representation of the seasonal descent of the thermocline is accurate.     

Large scale systems approach to estuarine water quality modelling with multiple constituents

A matrix model for simulating concentration distributions of water quality constituents with coupled reactions in an estuary is developed from a large scale systems approach. The model is an approximation to the set of coupled partial differential equations describing the process. This steady state approximation is formulated as a large algebraic system consisting of coupled subsystems. The large algebraic system is solved by an efficient iterative method. Results utilizing actual field data are presented for the nitrogen cyle with five constituent forms of nitrogen for Corpus Christi Bay, Texas. Simulated and observed concentrations are compared.     

Suspended particulate matter dynamics in a particle framework

Suspended particulate matter (SPM) dynamics in ocean models are usually treated with an advection–diffusion equation for one or more sediment size classes coupled to the hydrodynamical part of the model. Numerical solution of these additional partial differential equations unavoidably introduces numerical diffusion, i.e. in the case of sharp gradients the possible occurrence of artificial oscillations and non-positivity. A Lagrangian particle-tracking model has been developed to simulate short-term SPM dynamics. Modelling individual sediment particles allows a straightforward physical interpretation of the processes. The tracking of large numbers of individual and independent particles (up to 25 million in total in a single sediment class) can be achieved on high performance computer clusters, due to efficient parallelisation of particle tracking. The movement of the particles is described by a stochastic differential equation, which is consistent with the advection–diffusion equation. Here, the concentration profile is represented by a set of independent moving particles, which are advected according to the 3D velocity field, while the diffusive displacements of the particles are sampled from a random distribution, which is related to the eddy diffusivity field. To account for erosion a new parameterisation is proposed. Three numerical particle tracking schemes (EULER, MILSTEIN and HEUN) are presented and validated in idealised test cases. Finally, the particle tracking algorithms are applied to a realistic scenario, a severe winter storm in the East Frisian Wadden Sea (southern North Sea). The comparison with observations and an Eulerian SPM transport model seems to indicate a somewhat better fidelity of the Lagrangian approach.     

A boundary value approach for estuarine water quality modelling with results for Jamaica Bay,New York

Results of water quality modelling for Jamaica Bay, a New York estuary with a large hydraulic circulation, are presented. The two-dimensional topology is approximated by a set of coupled one-dimensional subsystems. The long term steady state water quality problem is then reformulated as a multi-point boundary value problem for ordinary differential equations. Piecewise constant dispersion parameters are estimated from salinity data.A sequential algorithm based on parallel shooting is developed for solving the multipoint problem. The method, which simplifies handling of feedforward and feedback reaction kinetics, is equivalent to employing a high order finite difference technique with the subsequent enhanced accuracy.Results of model verification for uncoupled variables — salinity, coliform, total soluble phosphorus, and coupled variables for nitrogen (organic and ammonia) and BOD-DO for Jamaica Bay are discussed.