生化过程的非结构模型和结构模型

本文介绍了生化过程的两类主要的数学模型——非结构模型和结构模型的结构和建模方法。并在分析两者特点的同时。提出了今后有关这类过程模型化的对策之设想。     

磁滞模型研究进展

简述了磁滞以及更具一般性的材料滞回特性的主要特征。给出了常见滞回模型的性能对比和分析。重点介绍了磁性材料中常用的Jiles—Atheron模型、Preisach模型、斯通纳-沃尔法斯模型的概念和应用情况,特别是面对新材料磁滞特征模拟时它们的主要问题以及研究的进展情况。     

三元催化转化器数学模型的发展研究

介绍了三元催化转化器的结构及工作原理,论述了目前开发出的催化转化器的各种数学模型,包括温度模型,二维模型,多维模型,及动力学模型等。对今后催化转化器数学模型的研究方向做了展望。     

A framework of hybrid model development with identification of plant-model mismatch

Hybrid modeling has attracted increasing attention in order to take advantage of the additional data to improve process understanding. Current practice often adopts mechanistic models to predict process behaviors. These mechanistic models are based on physical understandings and experimental studies, but they sometimes lead to plant-model mismatch (PMM) as they may be inaccurate to fully describe real processes. Black-box models can serve as an alternative, but they often suffer from poor generalization and interpretability. To combine the two techniques, hybrid models are developed to make use of process data while maintaining a degree of physical understanding. In this work, we implement a framework of identification of PMM using partial correlation coefficient and mutual information, followed by introducing and comparing serial, parallel, and combined structures of hybrid models. The framework is applied and tested with a simulated reactor model and two pharmaceutical unit operation case studies.     

Derivation of a control oriented low order model of the dynamics of an infrared oven for the continuous drying of a thin sheet of material

A model consisting of three partial non-linear differential equations for describing the humidity and temperature of a thin sheet of material and of the temperature of the air flow as a function of time and position in an infrared dryer was reduced to a model more adaptable to direct digital control. To begin with the original model was discretized along the length of the dryer and then linearized. Models of orders ranging from 12 to 72 were analyzed for controllability and observability. Using Moore's method, the models thus obtained were further reduced to a controllable state space model of order 5 that produced satisfactory results and for which stability was preserved. Simulated open loop responses of the reduced model to discrete perturbations in emitter electrical power, inlet humidity and velocity of the web, produced satisfactory dynamic and steady-state responses when compared to responses of the original model subjected to similar perturbations. The steady-state responses showed absolute errors for humidity and temperature of the web less than 1.3% [g water/100 g] and 2.2°C, respectively.     

页岩气吸附模型的研究进展

为了更好地拟合页岩气吸附实验,研究了经典的langmuir模型,发现其局限性。为了弥补langmuir模型的局限性,相继列举了数个页岩气吸附模型如EL模型、双langmuir模型、BET模型和D-R模型等,各个模型都有其优势与不足。我们需要根据特定的条件,选择合适的页岩气吸附模型才能更精准地拟合页岩气吸附实验。     

电解质NRTL模型的发展及应用

综述了电解质NRTL模型从最初的用于处理单一电解质、单一溶剂体系的两贡献模型发展成为能处理多电解质组分、混合溶剂体系的热力学模型，介绍了模型在电解质溶液相平衡计算中的应用。最后指出了此模型的优缺点和模型参数的发展方向。     

煤化学结构模型研究进展及应用

为了解煤结构与反应性之间的关系,论述了褐煤、次烟煤、烟煤、无烟煤的典型化学结构模型,分析了煤的化学结构模型在煤热解、煤气化、煤液化、煤自燃及煤的溶剂溶胀性中的应用。煤的化学结构模型有助于在分子水平上研究煤反应过程中的反应路径和反应机理。煤结构模拟的方法能够有效捕获煤热解过程中化学键的生成和断裂行为,解释煤气化反应机理,有效检测或捕获煤液化时生成的不稳定自由基,从微观方面分析影响煤自燃的因素,达到预防煤炭自燃的目的。     

Fault Prediction Based on Dynamic Model and Grey Time Series Model in Chemical Processes

This paper combines grey model with time series model and then dynamic model for rapid and in-depth fault prediction in chemical processes. Two combination methods are proposed. In one method, historical data is in-troduced into the grey time series model to predict future trend of measurement values in chemical process. These predicted measurements are then used in the dynamic model to retrieve the change of fault parameters by model based diagnosis algorithm. In another method, historical data is introduced directly into the dynamic model to re-trieve historical fault parameters by model based diagnosis algorithm. These parameters are then predicted by the grey time series model. The two methods are applied to a gravity tank example. The case study demonstrates that the first method is more accurate for fault prediction.     

SOME PROPERTIES OF CONDITIONAL QUASI-LIKELIHOOD FUNCTIONS FOR TIME SERIES MODEL FITTING

Abstract. We consider fitting a parametric model to a time series and obtain the maximum likelihood estimates of unknown parameters included in the model by regarding the time series as a Gaussian process satisfying the model. We evaluate the asymptotic value of the conditional quasi-likelihood function when the number of observations tends to infinity. We show what properties of the time series we can find by examining the behaviour of the conditional quasi-likelihood function, even when the time series does not necessarily satisfy the model and is not necessarily Gaussian.     

热裂解制乙烯裂解炉的工艺数学模型和模拟

对乙烯生产过程的数学模型发展状况作一概述。按对反应管轴向和径向处理的方法，裂解炉的工艺数学模型可分为一维模型和二维模型，对一维模型与二维模型的模型假定、主要公式及研究现状进行描述。     

多层次结构模型预测控制系统的层次间模型切换方法

引言实际的工业过程对象,大部分都呈现出很强的非线性特性,其控制过程十分复杂。虽然近年来,对非线性技术的研究已经取得了很多的成果。但是非线性系统精确建模困难[1]、非线性微分方程求解     

Dynamic Models for Drying and Wet-Milling Quality Degradation of Corn Using Neural Networks

ABSTRACT

Non-linear dynamic models of corn drying and wet-milling quality degradation are obtaineddirectly from experimental data. No assumptions about the underlying mechanisms are made. Relative advantages of recurrent versus explicit-time models and technical issues are discussed. This type of model is well suited for very fast on-line simulations, for example in a predictive optimal control algorithm.     

以LOM原型为基础的电铸载体选择

本文以LOM原型为基础，分别制作环氧树脂模型、硅胶模型、吸塑件模型石膏模型，并对这四种模型做电铸载体的可行性进行分析，在不影响电铸质量的前提下，根据不同结构特征可以选择合适的电铸载体。     

加氢裂化反应动力学模型研究及应用进展

加氢裂化技术在石化行业中的地位已举足轻重。为深入了解加氢裂化反应规律、优化工业装置运行工艺条件和产品分布,实现炼化企业智能化和效益最大化的目标,科研人员对加氢裂化反应动力学模型做了广泛的研究。对加氢裂化反应动力学模型相关研究及应用进展做了综述,介绍了加氢裂化反应动力学模型研究历程,研究目标从初期简易宏观的关联模型发展为按馏程或其他生产方案需求划分的传统、连续集总模型,再进一步发展为复杂微观的分子集总模型;概述了不同加氢裂化反应动力学模型的应用情况,突出说明了传统集总模型的工业实用性和分子集总模型原料、产品适用性;指出有效地将关联、集总模型（尤其是分子集总）结合利用,开发一种全面的混合动力学模型,将是未来加氢裂化以及其他石油加工过程反应动力学模型研究中极具意义和挑战的工作。     

电解质NRTL模型的研究进展及应用

电解质NRTL模型是重要的热力学局部组成模型。本文阐述了电解质NRTL模型的研究进展过程,包括模型的提出、修正、改进和扩展,同时指出了不同模型的适用范围。介绍了模型在各种复杂电解质溶液体系关联计算中的应用,可以为一些工业生产过程的模拟、设计和优化提供理论指导。电解质NRTL模型的主要优势是适用的温度和浓度范围宽,不需二元以上高阶参数;但模型自身也存在缺陷,如参数的回归工作量大、在溶液体系临界点处的预测精度较差等,故模型仍需进一步完善。     

规整填料波纹结构上的二维两相流模拟方法

规整填料是由规则排列的波纹板组成的。液相是沿着波纹板壁面往下流动,而气相则是在波纹板之间形成的通道内与液相呈并流或逆流的状态。因此,气液两相的水力学特性决定着填料塔的操作弹性和质量传递效率。波纹板上的液膜流动状态因在很多应用领域都发挥作用而备受关注。本文从物理建模、自由界面处理方法、表面张力模型以及湍流模型等方面对规整填料波纹板上的二维液膜数值模拟方法作了详细的陈述,并且对该领域的研究现状作了进一步分析和总结。     

色谱分离动力学的理论模型及其应用

色谱模型是研究色谱分离过程的基础，对于描述该过程中质量传递动力学和吸附过程具有非常重要的帮助。本文对近年来色谱分离动力学研究常用理论模型的发展进行了综述，重点介绍了普遍化速率模型、集总孔扩散模型、平衡扩散模型和传递扩散模型4种常用的色谱模型，并讨论了各模型的优缺点及应用范围。     

结合传热单元仿真模型的开发谈建模的基本要求和步骤

在PSSP系统上建立传热单元仿真模型应以提供传热单元培训服务为目的，针对性要强，满足用户的要求，对模型算法要进行合理的开发，建模时，要分析工艺流程，绘制工艺流程图，收集有关工艺数据，进行物料，组分衡算，并绘制全局模块流程图。     

MATHEMATICAL MODEL FOR REDUCTION OF COKE FORMATION DURING HYDROCARBON PYROLYSIS USING ADDITIVES

A mathematical model has been developed to simulate reduction of coke formation by additives during hydrocarbon pyrolysis. In this model it is assumed that the formation of coke is mainly due to surface catalytic reactions. The adsorption of additive agents on the reactor surface, therefore, effectively reduces the formation of coke. Using this model, it is found that the higher the additive concentration the faster the formation of the protective layer, and hence the rate of coke formation approaches its steady state value more quickly. The developed model is simple and the predicted results are reasonable.