基于元胞自动机的分布式水文模型研究

元胞自动机是一个时空离散的动力学模型,是复杂系统的研究方法之一。将元胞自动机这一新方法工具应用到分布式水文模型中,为分布式水文模型的发展提供一种新的思路。简要介绍元胞自动机的定义和构成等基本理论,针对水文研究领域的特殊性,扩展元胞自动机的定义,将元胞自动机和分布式水文模型相结合提出元胞自动机水文模型(CAHM),对元胞自动机水文模型的建模方法及模型结构进行阐述,并对元胞模型应用于分布式水文模型的优势及面临的问题进行分析。     

基于突发事件的城市地铁客流应急疏散模型与仿真分析

面向地铁突发事件，以组合建模的视角研究地铁客流应急疏散问题。首先对突发客流及其疏散的影响因素进行分析，运用元胞自动机理论构建了地铁客流应急疏散的组合模型，包括行人最优路径选择模型、行人移动模型、障碍物绕行模型、变道和超越模型等。然后以西安市青龙寺地铁站为例进行实证分析，采用AnyLogic软件平台仿真分析了地铁客流应急疏散的过程。研究结果表明：在紧急疏散过程中，行人密度比较大的状态下，出口及路径等关键信息如果不能完全掌握，将导致站台层与站厅层间的通道出现拥挤现象。当及时发布疏散的实时信息，工作人员现场控制出站人流行走的通道和秩序时，拥堵人群可以得到有效疏散。     

元胞自动机方法模拟微观组织演变的建模框架

基于元胞自动机模型的框架特性，构建了基于扩展的元胞自动机的模型框架MicrosCA。该模型不是针对某一具体应用的实际模型，而是一个通用的模型框架，阐述了构建微观组织模拟元胞自动机模型的主要思想、微观模型与其它模型间的集成。在此基础上，可以针对不同应用问题，对其进行适当细化和具体化，以适合各种组织演变问题的分析研究。     

元胞自动机模型方法及其在材料组织结构模拟中的应用

元胞自动机是复杂体系的一种理想化模型 ,它对处理那些难以用数学定量描述的复杂动态体系问题如材料的组织结构演变问题有独到之处 ,并且特别便于计算机模拟实施。本文介绍了元胞自动机的基本思想、分类与特征 ,并综述了元胞自动机模型方法在材料的凝固结晶、再结晶和晶粒长大以及相沉淀和相分解的模拟研究中的应用。     

元胞自动机：一种探索管理系统复杂性的有效工具

元胞自动机能利用简单的局部规则和离散方法描述复杂的全局的连续系统,已成为探索复杂系统的 一种有效工具。文章阐述了元胞自动机的发展历程、结构、特征及基本理论与方珐;介绍了元胞自动机在寡头 垄断行为、交通管理及工程运输、城市发展、市场营销、股票投资、企业战略等管理领域中的应用;指出元胞 自动机理论的优势与不足,并提出进一步的研究展望。     

基于改进边界条件的元胞自动机模型研究

元胞自动机方法在模拟过程中,必须用特殊的算法对边界进行处理才能避免边界出现杂质及失真.提出了基于Moore型邻接的改进边界条件算法并进行了模拟.通过与随机型边界条件模拟结果的对比,表明改进算法有利于模拟区域四角和四边的处理,可以应用于元胞自动机模拟中.     

元胞自动机模型方法及其在材料组织结构模拟中的应用

元胞自动机是复杂体系的一种理想化模型。它对处理那些难以用数学定量描述的复杂动态体系问题如材料的组织结构演变问题有独到之处，并且特别例于计算机模拟实验。本文介绍了元胞自动横的基本思想、分类与特征，并综述了元胞自动机模型方法在材料的凝固结晶、再结晶和晶粒长大以及机沉淀和相分解的模拟研究中的应用。     

二维可控细胞自动机伪随机序列发生方法研究

提出了一种新的细胞自动机———二维可控细胞自动机。根据二维可控细胞自动机的性质,提出了一 种具有梯型结构的二维可控细胞自动机的伪随机序列发生方法。计算机模拟表明,具有梯型结构的二维可控细 胞自动机伪随机序列发生器实现简单,产生的序列具有速度高、统计特性好等优点。新的细胞自动机在对称密 码学中有广泛地应用。     

激光合金化中SiC颗粒对镁合金热影响区晶粒生长的CA模拟研究

基于晶界能和晶界曲率的晶粒生长驱动力理论,建立了二相粒子晶粒生长的元胞自动机模型。将二相粒子SiC对镁合金激光合金化中晶粒生长进行了模拟。结果表明,模拟过程稳定,模拟结果与其微观组织相吻合,建立的元胞自动机模型适用于SiC颗粒对镁合金激光表面合金化的晶粒生长情况。     

多障碍情境下矿工紧急疏散建模及仿真

为克服基于最短距离方法构建的地面场在指引元胞移动时由于路径上存在障碍物而不可行的弊端,提出了一种用元胞格点到出口的最短路径构建地面场的新方法。在此基础上,以多障碍情景下的矿工疏散问题为例,假设矿工以无后退移动方式疏散,建立了矿工紧急疏散模型,并用Matlab进行了仿真模拟。结果表明,构建的模型能够真实地模拟矿工的疏散行为,平均疏散时间随位置保持概率增大而迅速增大的模拟结果与实际情况相符。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.