卷烟厂制丝线生产过程建模与计划仿真技术研究

本课题结合国家863高技术计划“面向流程与混合行业的可配置MES产品及行业解决方案”项目2007AA040702和“吉林省延吉卷烟厂制丝生产线生产管理系统”项目选题进行研究与软件开发。是项目研究的主要内容之一，本人主要负责仿真模型建立模块中各项功能的设计与开发。 烟草行业作为一个特殊的行业，它面临着来自市场和国家计划的双重压力，面对这些压力，为了更好的应对市场，烟草企业采用制造执行系统(Manufacturing Execution System，MES)来对卷烟的整个生产过程进行管理。用于完成制丝的制丝生产线是烟草企业最重要的环节，它的工作性能直接决定了卷烟的质量及生产效益。其中，计划的合理性程度以及具体的执行情况是影响其工作性能的关键因素。当前制丝线MES系统的计划调度模块是通过基于规则的调度策略来获得调度方案以对制丝线的生产进行管理，这些规则是根据实际的经验从生产现场抽取得到，在一定程度上保证了计划调度的合理性，但不能保证获得符合实际情况的最优的调度方案，并且在此过程中没有考虑异常事件发生时的应对措施，由于这种调度策略的局限性以及生产线中异常事件发生的随机性，当前制丝线MES系统的计划调度模块已无法很好的管理制丝线的生产。 为解决上述问题，本文在对卷烟厂制丝线生产过程进行建模的基础上，提出并开发了制丝线的计划仿真系统。通过仿真模拟整个制丝生产过程，不仅能确定计划制定的合理性程度，还能预测异常事件发生时对整个计划执行的影响程度，进而采取相应的措施来保证生产的效率。本文的主要研究工作如下： 1、概述了当前主要的生产过程建模方法和离散事件仿真方法，对每种方法的特点进行了概括和总结，在此基础上提出了本文所采用的建模和仿真方法。其中的仿真方法较已有方法在程序实现上做了改进。 2、在对现有的烟草企业制丝线生产过程进行分析的基础上，采用面向对象的建模方法对其进行建模，为生产计划仿真提供基础。 3、设计了生产计划仿真系统的整体框架，对各功能模块设计、系统设计及其实现技术作了细致的阐述。 4、开发实现了该计划仿真系统并针对延吉卷烟厂新厂区制丝线进行计划仿真，分析表明，仿真效果良好。

Numerical simulation of rock failure and earthquake process on mesoscopic scale

On the basis of the lattice model of MORA and PLACE, Discrete Element Method, and Molecular Dynamics approach, another kind of numerical model is developed. The model consists of a 2-D set of particles linked by three kinds of interactions and arranged into triangular lattice. After the fracture criterion and rules of changes between linking states are given, the particle positions, velocities and accelerations at every time step are calculated using a finite-difference scheme, and the configuration of particles can be gained step by step. Using this model, realistic fracture simulations of brittle solid (especially under pressure) and simulation of earthquake dynamics are made.

Molecular Dynamics Simulation of Barnacle Cement

Barnacle cement is an underwater adhesive that is used for permanent settlement. Its main components are insoluble protein complexes that have not been fully studied. In present article, we chose two proteins of barnacle cement for study, 36-KD protein and Mrcp-100K protein. In order to investigate the characteristic of above two proteins, we introduced the method of molecular modeling. And the simulation package GROMACS was used to simulate the behavior of these proteins. In this article, before the simulations, we introduce some theories to predict the time scale for polymer relaxation. During the simulation, we mainly focus on two properties of these two proteins: structural stability and adhesive force to substrate. First, we simulate the structural stability of two proteins in water, and then the stability of 36-KD protein in seawater environment is investigated.We find that the stability varies in the different environments. Next, to study adhesive ability of two proteins, we simulate the process of peeling the two proteins from the substrate (graphite). Then, we analyze the main reasons of these results. We find that hydrogen bonds in proteins play an important role in the protein stability. In the process of the peeling, we use Lennard–Jones 12-6 potential to calculate the van der Waals interactions between proteins and substrate.

Mechanical modeling of grain boundary sliding of polycrystals

Using a variational method, a general three-dimensional solution to the problem of a sliding spherical inclusion embedded in an infinite anisotropic medium is presented in this paper. The inclusion itself is also a general anisotropic elastic medium. The interface is treated as a thin interface layer with interphase anisotropic properties. The displacements in the matrix and the inclusion are expressed as polynomial series of the cartesian coordinate components. Using the virtual work principle, a set of linear algebraic equations about unknown coefficients are obtained. Then the general sliding spherical inclusion problem is accurately solved. Based on this solution, a self-consistent method for sliding polycrystals is proposed. Combining this with a two-dimensional model of an aggregate polycrystal, a systematic analysis of the mechanical behaviour of sliding polycrystals is given in detail. Numerical results are given to show the significant effect of grain boundary sliding on the overall mechanical properties of aggregate polycrystals.

Molecular Dynamics Simulation of Barnacle Cement

Barnacle cement is an underwater adhesive that is used for permanent settlement. Its main components are insoluble protein complexes that have not been fully studied. In present article, we chose two proteins of barnacle cement for study, 36-KD protein and Mrcp-100K protein. In order to investigate the characteristic of above two proteins, we introduced the method of molecular modeling. And the simulation package GROMACS was used to simulate the behavior of these proteins. In this article, before the simulations, we introduce some theories to predict the time scale for polymer relaxation. During the simulation, we mainly focus on two properties of these two proteins: structural stability and adhesive force to substrate. First, we simulate the structural stability of two proteins in water, and then the stability of 36-KD protein in seawater environment is investigated. We find that the stability varies in the different environments. Next, to study adhesive ability of two proteins, we simulate the process of peeling the two proteins from the substrate (graphite). Then, we analyze the main reasons of these results. We find that hydrogen bonds in proteins play an important role in the protein stability. In the process of the peeling, we use Lennard-Jones 12-6 potential to calculate the van der Waals interactions between proteins and substrate.

Bump-Surface Multicompartment Micelles from a Linear ABC Triblock Copolymer: A Combination Study by Experiment and Computer Simulation

Novel bump-surface multicompartment micelles formed by a linear amphiphilic ABC triblock copolymer via self-assembly in selective solvent were successfully observed both in simulation and experiment. The results revealed that the block A forms the most inner core, and the blocks B and C form the inner and outer layers, respectively, and the bumps were formed by block A and more likely to be born on curving surfaces. Moreover, the micelle shape could be controlled by changing the solvent selectivity of the blocks A and B. Spherical, cylindrical, and discoidal micelles with bumpy surfaces were obtained both in experiment and simulation.

Investigation of sol-gel transition in Pluronic F127/D2O solutions using a combination of small-angle neutron scattering and Monte Carlo simulation

Physical gelation in the concentrated Pluronic F127/D2O solution has been studied by a combination of small-angle neutron scattering (SANS) and Monte Carlo simulation. A 15% F127/D2O solution exhibits a sol-gel transition at low temperature and a gel-sol transition at the higher temperature, as evidenced by SANS and Monte Carlo simulation studies. Our SANS and simulation results also suggest that the sol-gel transition is dominated by the formation of a percolated polymer network, while the gel-sol transition is determined by the loss of bound solvent. Furthermore, different diffusion behaviors of different bound solvents and free solvent are observed. We expect that this approach can be further extended to study phase behaviors of other systems with similar sol-gel phase diagrams.