气化炉自动建模系统研究

为了减轻建模人员在建模公式推导、逻辑关系推导和编制仿真程序的工作量，设计了气化炉自动建模系统。该系统在反应物为多种气体、多种固体（均考虑为单筛分）的条件下，按照小室模型的框架自动列写相应各个物质的质量、能量平衡方程，并自动生成相应的计算机程序，方便仿真计算。由于该系统避开了工程中常用的纯数值建模的思路，采用了新的数学工具－以符号运算特长的计算机代数系统为计算平台，才使得该系统具有强大的逻辑关系推导能力。该系统在某气化炉的建模过程中得到了验证和示范，事实表明：该系统大大减少了气化炉的建模工作量，特别是减少由于化学反应假定的不同带来的建模复杂性，对于建模与仿真研究新方法的突破有所贡献。     

储层石蜡沉积预测技术研究与应用

在油田开发过程中 ,由于油藏温度、压力等条件的变化 ,高含蜡原油在近井带容易产生石蜡沉积 ,堵塞地层孔隙或裂缝 ,严重影响油田开采 ,尤其对于低渗油田 ,伤害特别严重。文中应用理想溶液理论、质量守恒和能量守恒等基本原理 ,建立更符合油田实际情况的油藏中石蜡沉积预测数学模型 ,开发一套方便实用的油藏中石蜡沉积预测软件系统FPOS1 0。在此基础上 ,应用室内实验数据和现场数据对吉林新民油田油井石蜡沉积情况进行预测和现场拟合 ,确定新民油田临界石蜡沉积半径为 2 5m ,快速、准确地为现场清防蜡措施提供理论依据。     

多工况多级离心压缩机总体优化命题的建模与数值方法

介绍了多工况 点的压缩机最优模拟设计点的特点及相应的优化建模，包括目标函数的建立、约束条件的确立和计算方法，使满足该模拟设计点要求的压缩机在逼近优目标函数最大值的同时，兼顾各真实工况运行点都在较好效率下工作，并列出了基于模型级数据库的优化设计实例。     

复杂压力系统地层压力预测方法在文东油田的应用

建立了复杂压力系统地层压力预测方法的数学模型 ,并利用文东油田文 13块已钻井的测井资料、采油注水井的地质资料 ,预测了 4口调整井的孔隙压力、坍塌压力、破裂压力 ,并据此推荐了实钻时所采用的钻井液密度 ,取得了良好的施工效果     

Mathematical modelling of a reverse flow reactor with catalytic surface dynamics

This paper studies a system of partial differential equations modelling the behaviour of a reverse flow reactor. For the parameters appropriate for the oxidation of ammonia on a Pt/Al₂O₃ catalyst in a typical laboratory set-up, the reactor may be split into regions where approximate formulas that determine its behaviour are deduced. Numerical calculations are presented and can be used to compare with the analytical formulas. The physical insight gained from the asymptotic analysis suggests a new switching strategy which is the subject of numerical experiments. The switching strategy is found to be efficient at minimising the ammonia exiting the reactor after reversal.     

Semantic Transparency,Brain Monitoring and Evaluation of Hybrid Cognitive Architectures

In constructing hybrid systems, there is a need for a principled basis to determine the relative roles or functions of artificial neural network and symbolic approaches. The primary objective of the work to be reported is the construction of a conceptual and methodological framework that permits an iterative sequence in which a hybrid model predicts the basis of cognitive performance and an objective analysis of performance provides empirical data, evaluating (and thus constraining) the structure and processes of the model. In seeking a linkage between a hybrid model of cognition and human performance the concept of “semantic transparency” has been adopted, since it can be used in analyzing and describing both the chracteristics of a model of cognition and the processes underlying human performance. An overview of a specific, ”strong” hybrid architecture is presented. The characteristics of the virtual machines which compose it and the nature of their interaction are illustrated. An approach to the questions of evaluation is described based on empirical data obtained by brain monitoring of subjects during cognitive performance.     

The preparation and properties of coprecipitated Cu–Zr–Y and Cu–Zr–La catalysts used for the steam reforming of methanol

Several samples of exhaust diesel soot are investigated by inverse gas chromatography and linear solvation energy relationship (LSER) modelling according to their soluble organic fraction content and their time of exposure in oxidative conditions. The results demonstrate the evolution of the adsorptive properties of the studied materials towards volatile compounds during the oxidation under NO₂.     

Finite element micromechanical modelling of unidirectional fibre-reinforced metal-matrix composites

Typical finite element formulations and models for unidirectional composite materials are reviewed. The application of micromechanical finite element analysis to the modelling of unidirectional fibre-reinforced metal-matrix composites is demonstrated by presenting some studies from recent publications. It is shown that while analytical models offer a simple tool for obtaining the overall response of composites, finite element analysis provides more accurate and detailed characterisation of composite properties for complicated geometries and constituent property variations. Various effects that influence the stress/strain response and fibre/matrix deformation of composites are studied through modelling. These effects include the fibre coating and reaction layer, fibre shape and distribution, metallurgical and environmental factors, stress distributions and damage. It is demonstrated that the properties and constituent phase interaction of metal-matrix composites are best modelled by finite element analysis. It is emphasized that in order to obtain good predictions, the models must be coupled with first-hand characterisations of the constituent phases and their interactions, including the thermal history of the specimens.     

Simulation of water and nitrogen dynamics in soils during wastewater applications by using a finite-element model

A mathematical model was developed to simulate water movement, mass transport, and nitrogen transformations in soils during wastewater applications. The model is one-dimensional and based on the Galerkin finite-element method. The submodel of mass transport of nitrogen incorporates the convection-dispersion processes of ammonium and nitrate nitrogen, nitrification, denitrification, ammonium exchange and uptake of ammonium and nitrate ions. The accuracy and validity of the proposed model was examined by comparison with an explicit-implicit finite-difference model results. The model was used for simulation of water and nitrogen dynamics during wastewater application in homogeneous and multi-layered soils under different N concentration, rate, duration and scheduling of application.