PNBR增韧改性SMC的研究

以粉末丁腈橡胶(PNBR)作为低收缩添加剂改性不饱和聚酯(UP)基片状模塑料(SMC),考察PNBR用量对改性SMC:物理性能的影响.结果表明,PNBR能够显著降低改性SMC的收缩率,可将收缩率变化控制在3%～5%,同时较大幅度地提高改性SMC的抗冲击性能;PNBR的适宜用量一般为8～10份;SEM和TEM表明,PNBR与SMC基体在相界面处能够形成梯度互穿网络结构.加强了两相界面的结合.     

Basics of process modeling

Modeling in Chemical Engineering should as a major objective possess the capability to predict. But, what does one know about the reliability of prediction?This article reviews earlier and recent studies and thinking on this matter: the relation to fundamentals, the role of mathematics and computing, the place of dimensional analysis and the connection between micro- and macro-scale events.     

粉末丁腈橡胶改性SMC的研究

采用粉末丁腈橡胶(PNBR)和PNBR/聚苯乙烯(PS)体系改性SMC复合材料,研究了玻纤、CaCO3、PNBR和PNBR/PS体系对SMC的收缩率、力学性能和表面质量的影响。结果表明:玻纤和CaCO3能降低SMC的收缩率,但效果较小,CaCO3对表面质量有积极作用,其最佳质量分数为41.5%;PNBR的加入显著地降低了SMC的收缩率,同时提高了韧性,当其质量分数为5.2%时,收缩率达到0.05%以下;PNBR/PS体系的抗收缩效果优于PNBR,当PNBR/PS质量比为1∶2时,能够实现零收缩,而且改性SMC具有优良的力学性能和表面质量。     

SMC创新集锦

汽车行业的OEM（原始设备制造商）早在1950年就开始使用SMC（片状模塑料）。自70年代初期的燃料危机迫使汽车制造商想法减轻车辆重量以来，SMC就成了一种减轻重量的解决方案。SMC是用聚酯树脂（或乙烯基酯树脂、环氧树脂）、短切玻璃纤维、各种添加剂和填料制成的。与钢材相比，SMC可减重30％之多。自问世以来，SMC主要用于汽车制造业。     

Kinetic modeling of FCC process

Catalytic cracking of petroleum fractions a process termed as FCC is usually carried out in a reactor block with somewhat complicated hydrodynamic regime. The reactor block is considered as a combination of two different reactors. The riser is a near ideal plug-flow displacement of the catalyst and reaction mixture, while the main reactor vessel (separator) is considered as an ideal mixing CSTR. Temperature gradient along the plug-flow riser can vary on a linear and non-linear dependence. This is reflected by the thermal effect on the cracking products, along the altitude of the riser. Moreover, it can exert a considerable influence on the selectivity of the process in general, as characterized by the diversity of different hydrocarbon groups both in the gaseous and liquid products. The fluid catalytic cracking (FCC) is a process of conversion of a heavy oil fraction into lighter products in a catalytic fluidized reactor. The chemical composition and the structure of the feed are reflected on the catalyst's selectivity and the amount of coke deposited. It is, therefore, necessary to consider the feed type on modeling the process. Cracking reaction in the model was represented as a five-stage process. Reaction rates for the plug-flow riser and the ideal mixing separator are described mathematically in differential and algebraic forms. The model takes into account, exponential dependence of the specific reaction rate on temperature, as well as reflects the influence of the real and bulk catalyst densities, circulation rate, equilibrium and fresh catalyst's activities, reactor pressure, feed rate and unit construction. The model was developed based on a data taken from an industrial FCC unit, that were used to compute the kinetic constants and other parameters. Concrete computed kinetic parameters were compared with corresponding experimental data for adequacy. FCC process is in constant technological development with modernization of especially the riser reactor. Kinetic modeling of the catalytic FCC reactor will give a further understanding of the process and explain the complicated mechanism involved for an efficient and optimal conversion of the feed stock.     

Damage modeling of degradable polymers under bulk erosion

Unit micro‐cell models with different architectures were designed to simulate the degradation process and chemical damage behavior of degradable polymers under bulk erosion. The pores in the micro‐cell models were introduced to mimic the state of rapid water diffusion into the polymers under bulk erosion, while three different arrangements of pores were considered to investigate their effects on the degradation rate of different polymers with the same molecular weight. Different porosity levels were also used to study the degradation responses of the polymers having different molecular weights. A heat and mass transfer analogy was adopted to enable the analysis to be run on a general purpose finite element (FE) code. In the present work, a finite element software package ABAQUS incorporated with a user‐defined material subroutine was used to perform the analysis, in which a heat transfer function was utilized to simulate Fickian mass diffusion for the polymers through analogy. With the proposed method, the effects of chemical damage on the mechanical properties of the degradable polymers under bulk erosion could be predicted and the predicted trend of the mass loss of the polymers followed experimental results obtained from the open literature. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

轿车用SMC的研制

本文主要介绍了轿车用SMC模塑料的研制，通过选择合适的树脂及填料，严格控制增稠反应，采用短切与连续纤维并用的方法，研制出了满足奥迪轿车备胎仓使用要求的SMC模塑料。     

酚醛SMC

本文介绍了酚醛SMC材料的配方、加工工艺条件、各种性能和应用概况.     

SMC用高性能玻璃纤维的研究

通过对常规SMC用合股纱442C浸润剂配方进行优化,开发了新型442K产品,并用其增强热固性塑料制得复合模压片材。在使用过程中发现,442K的毛羽产生量较442C有明显下降。另外,442K制品的力学性能与常规442C制品相比有明显改善,特别是拉伸强度提升14%,并且制品表面质量也有所提高。该产品的成功开发进一步拓宽了其在SMC制品中的应用。     

基于k-近邻互信息的发酵过程高斯过程回归建模

发酵过程中基质浓度往往无法在线测量,采用高斯过程回归（GPR）建立基质浓度的估计模型,实现了其软测量。不同于传统软测量方法对基质浓度的估计,该方法不仅可以得到估计值,还能够得到其估计方差。考虑到发酵过程中各变量之间的非线性、相关性,为了提高模型的预测性能,在模型建立之前首先用k-近邻互信息（k-MI）辅助变量选择方法对模型的输入变量进行选择。从青霉素发酵过程的应用结果来看,采用kMI-GPR方法取得了较好的估计效果。     

间歇过程动态SDG建模

目前用于间歇过程的SDG建模方式不能达到计算机辅助HAZOP的要求,本文在现有SDG-HAZOP理论基础上提出了面对间歇过程的动态SDG建模理论,并详细阐述了如何运用SDG对间歇过程进行建模的思路和方法,并运用该方法对一个煤制油流程的除灰工序进行建模和分析,同时解决了间歇过程SDG建模的模型接续性与故障和危险覆盖面最大化两方面问题。     

基于FGCN的针铁矿沉铁过程建模

针铁矿沉铁过程是由多个连续反应器级联,并且包含氧化反应、还原反应以及中和反应等一系列复杂化学反应的复杂过程,具有强非线性、不确定性的特点,难以建立精确的数学模型。提出一种基于模糊灰色认知网络（fuzzy gray cognitive network,FGCN）的针铁矿沉铁过程的建模方法。根据专家经验和历史数据,建立针铁矿沉铁系统的模糊灰色认知网络模型,利用带终端约束的非线性Hebbian学习算法（nonlinear Hebbian learning,NHL）对权值进行学习。在不同程度的不确定性环境下对系统进行分析,结果表明模糊灰色认知网络能够在不确定性高的环境下对复杂工业系统进行有效模拟,收敛到一个灰度为零或者灰度很小的灰数平衡点,利用白化函数得到一个准确的控制输出。     

基于分阶段的LSSVM发酵过程建模

发酵过程建模是研究微生物发酵的重要课题,基于模型可实现被测参量的软测量、系统的优化控制。鉴于引入混合核函数的最小二乘支持向量机在过程建模中具有优良表现,采用基于混合核函数的最小二乘支持向量机建模。但由于发酵过程周期较长,最小二乘支持向量机的全局模型预测精度难以保证,算法复杂度很高,因此提出一种分阶段建模方法。首先,选择表征阶段特性的辅助变量,利用模糊C均值聚类算法对样本数据聚类,将发酵过程分成不同的阶段,然后为各个阶段分别建立最优混合核最小二乘支持向量机局部模型,最后将局部模型合成构成过程的完整模型。将此方法应用于青霉素发酵过程和重组大肠杆菌发酵过程中,验证了该方法的有效性。