汽车轴承支架生产线的仿真建模与优化研究

基于Flexsim仿真软件对某精密机械加工公司的汽车轴承支架生产线进行优化改造.首先识别生产线存在的问题,包括产能不足、设备和人员利用率不均衡等,接着建立生产线的仿真模型,有针对性地提出对工序、设备、布局和人员等几方面的仿真优化方案,最后实证研究表明,使用仿真软件进行生产线的优化,可以减少投资,缩短生产周期,是快速实现生产线改造、满足市场需求的有效途径,对提高企业的经济效益有极大的促进作用.     

基于Flexsim仿真技术在生产线上应用研究

制造企业的生产系统越来越复杂,为了科学地规划与布局生产线,越来越有效的方法是计算机仿真.为此,基于Flexsim仿真软件对浙江某有限公司炼漂车间生产系统进行仿真分析,以发现现有生产系统中的问题,进而对其进行改造,并对改造前后的生产线进行对比分析,得到生产系统仿真优化后的结果.     

基于Flexsim的制造车间生产线仿真优化研究

对制造企业生产线优化能有效降低运营成本。某制造生产车间同时生产三种产品,加工设备、生产线复杂。为提高生产效率,采用Flexsim仿真软件建立生产线模型,并通过仿真试验分析现有生产线瓶颈;采用增加加工设备、增加搬运设备及采用柔性生产调度方法等三种方案对生产线进行优化;结果表明,优化后的生产线投入产出率提高了13.83%,车间生产趋于平衡,同时,设备利用率也得到提高。     

基于遗传算法的TFT-LCD冲压生产线布局优化

为提高薄膜场效应晶体管液晶显示器(TFT-LCD)产品的生产效率,基于遗传算法对传统冲压生产线布局进行优化研究.以生产线物流费用最低为目标函数,生产车间总长度、总宽度和设备间保留最小间距等为约束条件,建立了TFT-LCD冲压生产线数学模型,通过编程求得优化解,并根据生产现场实际与自动化改造情况调整出较好布局优化方案.按优化方案进行试生产的测算结果表明,优化布局方案实施效果良好,与优化前布局相比,生产背板周期时间提高了25％,生产线平衡率提高了10％,日产量提高了33.3％,成本降低了25％.     

ATM中仿真数据库技术的研究与实现

封装测试生产线制造环境的复杂程度随着新品种和新设备的增加而增加.数据库技术对仿真系统的建立起决定性的作用.文章详细阐述了在半导体封装测试生产线上仿真数据库的建立方法,仿真软件实现的算法,以及在生产线上的实际应用. 在生产未运行之前预测生产线的生产能力、生产线在不同调度策略下的性能及预见随机故障发生时生产线的调节能力,选一个较好的调度方案来运行生产线.面向对象与多线程技术的运用,使得程序具有很好的可复用性和可扩展性.     

5m精轧机立辊回油管振动的FLUENT软件仿真

分析了宝钢厚板部生产5m宽钢板的精轧机立辊回油管振动情况,建立了管路的数学模型.利用Gambit软件建立回油管的三维模型并划分网格,采用流体动力学计算软件FLUENT对管路进行仿真分析.分析发现,回油管内的空穴和湍流是产生振动和噪声的原因.提出了回油管改造方法并进行了仿真验证,结果表明,改造后的回油管内空穴和湍流现象明显减少,有效地减轻了振动.本文工作对生产线的调试和最终运行提供了理论依据.     

基于Plant Simulation软件的地铁车辆车体生产产能分析

车体作为车辆的重要组成部分,提高车体产能是工厂日益迫切需要解决的问题.运用Plant Simulation仿真软件建立车体生产线模型,对生产过程进行仿真计算,识别瓶颈工序,提出解决方法.对关键设备的利用率进行计算,进行相应产能优化.结果表明,优化后的车体生产产能可以提升33.33%.     

价值流在中小型企业生产管理中的应用研究

通过现场的实际观察以及价值流对生产流程的分析,发现企业生产过程中出现生产线平衡率较低、增值时间比较低以及物流路线混乱等问题,利用工业工程方法对生产线平衡率进行改善,利用SLP方法对物流路线混乱以及增值时间比低等问题进行优化.针对价值流的短期性以及静态性的缺陷,提出利用仿真软件对仿真过程进行分析,弥补价值流的缺陷.通过改善,企业的增值时间比以及生产线平衡率都得到较大的改善.提高企业的生产运营能力,降低了企业的生产成本,对我国中小企业发展具有一定的现实意义.     

氨纶生产线模拟仿真系统

由于氨纶生产工艺复杂,生产周期长,原材料价格昂贵,不可能也不允许在生产线上进行操作优化或工艺参数的寻优试验。为此,建立了氨纶生产线模拟仿真系统,并在该模拟仿真系统上进行操作优化、工艺参数的寻优、原料配方、工艺调整等各种试验,取得成功后,在生产线上运行。该模拟仿真系统为企业的操作人员培训、生产设备故障的快速诊断提供了良好的操作平台。     

基于人员调度优化的混流生产线平衡改善

针对H企业单头电缆生产线在混流模式下生产线平衡较差的问题进行分析,发现该生产线目前的人力资源调度和配置难以适应作业负荷持续变动的生产现状.因此,以提高生产线平衡率并最小化生产线总人数和最优化各工序人员安排为目标建立数学模型,采用粒子群算法在MATLAB仿真软件中对算例模型进行求解,最终得出的最优人力资源调度方案使得生产线平衡率达到80%以上,进一步实现均衡化生产,提高企业的生产效率和生产响应能力.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.