关键词： 多环芳烃   超临界流体   萃取   正交   设计   模拟样品  

摘要： 采用正交设计实验方法，研究了从环境模拟样品中超临界流体萃取（ＳＦＥ）多环芳烃（ＰＡＨ）的最佳萃取条件。着重考察了超临界流体的压力、温度和用量等对萃取效率的影响。结果表明，压力的影响居第一位，温度影响次之，超临界ＣＯ２的用量的影响居第三位。

摘要： Current designs of electric tank furnaces with a fluidized bed that provide environmentally safe heat treatment of steels as tested under the conditions of machine-building plants are considered.

关键词： 人造卫星   微重力   控制   流体晃动  

摘要： 本文研究了关于旋转轴在贮箱的非对称轴上且远离贮箱的几何中心情况下，流体在微重力环境中由重力梯度加速度诱发的晃动特性，建立了问题的数学模型并对模型进行了数值模拟。以高级Ｘ射线天文物理实验卫星（简称ＡＸＡＦ─Ｓ）作为研究对象，获得了由旋转运动引起的重力梯度加速度的数学表达式。晃动问题的数值计算以与卫星固连的非惯性坐标系为基础，目的是寻求一种较为易处理且适合于流体力学方程的边界和初始条件。通过数值计算获得了流体作用于卫星贮箱上的力和力矩。

关键词： 微重力   晃动力学   气液界面   流体   力矩   模拟   科学实验卫星   重力梯度   加速度  

摘要： 本文研究了关于旋转轴在贮箱的非对称轴上且远离贮箱的几何中心情况下，流体在微重力环境中由重力梯度加速度诱发的晃动特性，建立了问题的数学模型并对模型进行了数值模拟，我们以精密X光光变天文物理实验卫星（简称AXAF－S）作为研究对象，获得了由于旋转运动引的重力梯度加速度的数学表达式。关于晃动问题的数值是以卫星固连的非惯性坐标系为基础，目的是寻求一种较为易处理且适合于流体力学方程的边界和初始条件，通过数值计算获得了流体作用于卫星贮箱上的力和力矩。

关键词： Degradation   Oxides   Anions   Environmental pollution   Organic compounds  

摘要： The photocatalytic degradation of two environmentally relevant organic compounds [4-chlorophenol (4-CP) and p-toluenesulfonic acid (PTSA)] was investigated using a novel cylindrical fluidized bed photoreactor (FBPR). Accumulated biodegradable organic acids, identified as intermediate reaction products, decreased after the removal of original pollutants. Measurements of the oxygen uptake rates with a mixed culture showed that all intermediate photooxidation products were much better biodegradable than the initial aromatic pollutants (4-CP, PTSA). The influence of HCO3- and Cl- on the degradation rate was also studied. For concentrations of 1 mM bicarbonate (HO. radical scavenger) and of 140 mM chloride (photo-inhibitor), the photocatalytic degradation rate decreased by 50%. During the photocatalytic reaction process, hydrogen peroxide accumulated in solution up to 0.21 mM depending on the initial concentration of the organic compounds and the concentration of dissolved oxygen. The relative quantum efficiency increased up to a factor of 2.3 by dosing of additional H2O2.

关键词： 超临界流体萃取   多环芳烃   环境   样品   回收   监测  

摘要： 本文研究了超临界流体的压力,温度和超临界CO_2的用量对超临界流体萃取多环芳烃回收率的影响及其影响规律,并建立了从环境模拟样品中萃取多环芳烃的萃取条件.还考察了在最佳萃取条件下超临界流体萃取多环芳烃的精密度,其RSD在3.71%～7.41%之间.

关键词： 毛细管   气相色谱   多环芳烃   超临界流体萃取  

摘要： 详细系统地研究了收集溶剂的种类、用量及无溶剂固体表面冷冻捕集等方法对离线收集超临界流体萃取多环芳烃组分效率的影响。研究发现，二氯甲烷和丙酮的收集效率较高，其回收率为６１．４４％～１０５．４０％，其它有机溶剂效果较差。而且，当收集溶剂的液面高度大于２．０ｃｍ时，溶剂的用量对收集效率没有明显的影响。玻璃珠固体表面冷冻捕集效果较好，其回收率在６０．９８％～１０９．８８％之间，但其精密度较差，相对标准偏差（ＲＳＤ）在０．２８％～１１．２９％之间。

关键词： Jets   Fluid dynamics   Mathematical models   Turbulence   Plumes (Fluid dynamics)  

摘要： The behaviour of a jet discharged in the middle of a long line of jets in a coflowing environment is modeled using a hybrid approach. The hybrid approach combines the integral and length-scale approaches to model the dispersion of a jet in a coflowing environment. Typical of a length-scale model, the jet's behaviour is divided into a number of distinct regimes in which a single parameter (formed from a combination of the governing parameters) dominates the behaviour of a jet. In this situation it is the initial excess momentum, ambient velocity and the port spacing that govern the behaviour of the jet. Length-scales can be formed by combining the dominant parameters in each regime and these length-scales represent the order of magnitude of the location of the transition between the flow regimes. In each regime the behaviour of the jet is modeled with the analytical solution of a relatively sirnple integral model. At the transition between the flow regimes the excess momentum and tracer fluxes of the integral jet solutions are matched. The advantage of this hybrid approach is that it enables the development of a relatively simple solution of a complex problem which retains the flexibility of a length-scale model, but the use of integral solutions reduces the dependence of the model on empirical information；The hybrid model predicts the velocity decay, radial growth and dilution of a jet as it moves downstream from the source and merges with its neighbors in a coflowing environment. A hybrid model has been developed using the FORTRAN programming language and it is given the name "JET". Predictions from JET have been compared with the full integral model solution for a merging jet in a coflow which was developed by Davidson (1989). Beyond the transition zone, the hybrid model fits the reference integral model well. At the transition zone, the hybrid model has an abrupt change between the different flow regimes and this introduces errors into the predictions. However, t

关键词： 超临界流体   萃取   环境分析