偏光显微定量分析针状焦微观结构方法的探讨

针状焦的显微组织结构与热膨胀系数(CTE)有着密切的关系,微观结构越好的针状焦其CTE就越小,反之CTE值就越大,因而它的显微结构能够从侧面反映其CTE指标的好坏。本文介绍了一种偏光显微定量分析方法,得到各类不同显微结构的含量分布;由于消光角的大小与织构的择优取向有关,引入消光角,又能够反映出光学各向异性取向程度,与定性分析相比,它更能直观地以数据形式来描述针状焦的微观结构。     

径向基神经网络在粉煤灰混凝土二维和三维碳化分析中的应用

研究了不同粉煤灰掺量(0%,15%,40%,60%)、不同水灰比(0.3,0.35,0.4)、不同强度等级下(C30～C50)高性能混凝土二维和三维碳化深度;应用多因子输入向量的径向基神经网络(RBF)进行二维和三维碳化深度的预测。试验表明,采用多因子输入向量的径向基神经网络能够在试验样本数量较少的情况下建立高效准确的预测网络,可以较好地预测混凝土的碳化深度,其二维和三维碳化深度预测精度比一维精度高,其一维,二维和三维碳化深度的预测值和试测值相对误差分别为10.9%,5.6%,7.1%。混凝土二维和三维碳化研究对混凝土结构耐久性和寿命预测具有现实意义。     

二维与三维边坡动力响应特性研究

基于FLAC-3D软件建立了二维和三维边坡模型,考虑地震加速度时程的输入,模拟不同尺度下边坡与坡脚的位移、速度以及剪应力响应特性,得出以下规律:随着地震波加速度时程的不断作用,位移呈非线性增长模式,三维边坡的最大竖向位移大于二维边坡的最大位移;水平速度随时间整体前期表现为先增大后降低趋势,后期呈不断波动的形式;三维边坡的水平速度最大值大于二维边坡的水平速度最大值;地震波对二维和三维边坡坡脚的位移、速度基本无影响。三维边坡剪应力云图大于二维边坡剪应力云图,表明地震波对三维边坡剪应力影响大于二维边坡,但幅度不大。     

欧特克创新模流技术亮相CHINA PLAS2015,引领行业实现未来智造

<正>在CHINA PLAS2015,全球二维和三维设计、工程及娱乐软件的领导者欧特克软件(中国)有限公司携业界领先的注塑成型仿真分析解决方案Autodesk~@Moldflow~@亮相"CHINA PLAS2015国际橡塑展",欧特克通过持续的技术创新,为橡塑企业提供前沿的注塑设计软件、洞察和资源支持,帮助设计师、     

三维电极系统处理垃圾渗滤液纳滤浓缩液的研究

构建了三维电极系统,对垃圾渗滤液纳滤浓缩液进行电催化氧化处理,并探讨催化反应机理。在5.5 V电压下用二维和三维电极系统对纳滤浓缩液进行处理,结果表明,三维电极系统的COD去除率为70.35%,显著优于相同条件下的二维电极系统(58.58%),三维电极系统出水中的可溶性有机物含量明显降低。粒子电极的加入提高了系统中H2O2和·OH的生成量,在污染物的降解和去除上有更优异的效能。     

有限元法在轮胎结构设计中的分析与应用

简要介绍了轮胎结构分析方法的发展过程，着重介绍了二维和三维有限元法在轮胎结构分析中的应用。通过对轮胎二维和三维有限元实际模型的分析比较．指出了它们各自应用的优缺点，并阐述了有限元法在轮胎结构分析和设计领域中的发展及应用前景。     

显微结构熵与ZrO_2马氏体相变

本文提出了反映材料显微组织结构状态的显微结构熵概念,通过热力学分析得到了显微结构熵变与ZrO_2马氏体相变起始温度的关系并得到了实验证明。     

煤矿压风设备三维可视化实时监控预警系统的实现

煤矿压风设备三维可视化实时监控及预警系统运用三维可视化虚拟仿真技术与PLC控制技术相结合对现场设备进行实时三维监控的半实物仿真系统。采煤现场各种设备的实时数据通过传感器采集后传输给PLC系统,PLC系统通过专用接口将数据传给上位机,再运用OPC技术将现场采集的数据实时存储进实时数据库中,最后,三维仿真模块根据数据库中的实时数据来控制虚拟环境中的各种设备进行动作。以Visual C＋＋和Eon作为开发工具,采用适合煤矿实体建模及应用的三维数据模型和数据结构,并采用几何建模、三维交互以及颜色、光照和材质等虚拟现实技术,开发煤矿三维可视化实时监控系统。     

煤岩显微类型对成焦性能的影响

分析测定了7种炼焦煤的煤岩显微组分、显微煤岩类型及其焦炭的显微结构,发现有机组分基质中,矿物质均匀分布有利于成焦,而团块或大颗粒矿物质分布不利于成焦,显微矿化类型比例较高、显微矿质类型比例较低的高灰焦煤和肥煤仍具有良好的成焦性能,可作为配煤使用;气煤和瘦煤的显微矿化类型比例对其成焦性影响较小。     

基于废料最少的反应器网络综合(Ⅱ)可得区分区策略

在本文 (Ⅰ )报的基础上 ,将反应器系统的纯组分进料拓展到任意组成进料的情况 ,提出了选择性最大曲线的概念 ,利用选择性最大曲线将二维和三维浓度空间的可得区分成三个区域 ,即完全混合区 ,PFR区和非操作区。通过分析不同区域及其连接边界的特性 ,可以简捷 ,方便地拟定适宜的反应器网络流程结构     

Finite element analysis of fracture statistics of ceramics: Effects of grain size and pore size distributions

A novel numerical simulation method based on finite element analysis (FEA), which can evaluate the fracture probability caused by the characteristics of flaw distribution, is considered an effective tool to facilitate and increase the use of ceramics in components and members. In this study, we propose an FEA methodology to predict the scatter of ceramic strength. Specifically, the data on the microstructure distribution (i.e., relative density, size and aspect ratio of pore, and grain size) are taken as the input values and reflected onto the parameters of a continuum damage model via a fracture mechanical model based on the circumferential circular crack emanating from an oval spherical pore. In addition, we numerically create a Weibull distribution based on multiple FEA results of a three‐point bending test. Its validity is confirmed by a quantitative comparison with the actual test results. The results suggest that the proposed FEA methodology can be applied to the analysis of the fracture probability of ceramics.     

Prediction of macroscopic effective elastic modulus of micro-nano-composite ceramic tool materials based on microstructure model

In order to investigate the effect of microstructure parameters on the elastic modulus, based on the microstructure model represented by Voronoi tessellation, the reasonable macro-micro connection and boundary conditions were proved through the Hill’s lemma, and the uniaxial tensile process of composite ceramic tool materials was simulated. The influences of grain size, second phase volume fraction and nanoparticle volume fraction on elastic properties were studied through numerical simulation, and the elastic modulus of composite ceramic tool materials was predicted. The results showed the elastic modulus of Al₂O₃-based ceramic tool materials could be increased effectively with the contents of the second phase TiB₂ and nano-particle TiC being 20% and 10%, respectively. The numerical simulation results were in good agreement with the experimental results.     

计算机仿真技术在陶瓷釉料工艺中的应用

利用计算机仿真模拟技术,研制了基于windows平台的陶瓷釉料工艺仿真系统。该系统改变传统工艺实验相对繁琐耗时的实验模式,实现陶瓷工艺实验方法的多元化,具备部分替代实物实验,减少能耗等优点。结果表明,仿真实验系统与实物实验相互配合,可提高实验效率,为打造全新的"低碳"陶瓷工艺实验技术提供条件,具有一定的推广价值。     

智能化风险及可操作性（HAZOP）分析系统研究进展

通过梳理智能化风险及可操作性（HAZOP）分析的各类方法,将其分为定性分析和定量分析两大领域,详细介绍了不同的研究方法及其优缺点,并结合实例对有代表性的方法作了详细阐述。智能化HAZOP定性分析系统的研究主要集中在建立专家知识库的方法上,其中基于深层知识建立专家知识库的研究相对较多,该方法虽然能够揭示偏差产生的机理、传递路径,但是分析结果准确度较差。基于经验知识、定性分析与定量分析相结合及基于动态模拟的HAZOP定量分析是实现智能化HAZOP定量分析的3种主要方法,是由模糊定量向精确定量、由静态分析向动态分析发展的过程。基于动态模拟的智能化HAZOP定量分析不仅研究偏差的数值,而且研究偏差的持续时间对过程系统的影响,分析结果更加精确,是较为完善的定量分析方法。该方法借助于商用模拟软件,使不具备丰富经验的分析人员也可以完成精确的HAZOP分析。"动态偏差的阶梯化求解法"使分析动态偏差方便、易行,基于该方法建立的偏差"层级"模型充分说明了处于不同层级的偏差对过程系统的不同影响。在分析智能化HAZOP分析系统发展历程基础上,结合最新研究进展,预测了其发展趋势。     

Influence of powder particle size on microstructure and performance of calcium oxide based ceramic core

A calcium oxide (CaO) based ceramic core used for titanium alloy casting was prepared by injection moulding technology. Through quantitative characterisation and statistical analysis of the microstructure, the influence of powder particle size on the microstructure and properties of the ceramic core was investigated. The results show that, by increasing powder particle size, the size of pores and porosities after sintering were increased with decreased of grain boundary density. Meanwhile, the flexural strength of ceramic core at room temperature was found to decrease with increasing core porosity, and the creep resistance of ceramic core increased with decreasing grain boundary density. The increase in powder particle size of ceramic core is beneficial to reduce linear shrinkage and improve high temperature creep resistance.     

定量显微学及其在陶瓷材料中的应用

介绍了定量显微学中的复合显微结构参数提取法、体视学方法和图象变换法及其在陶瓷材料中的应用实例。     

稀土氧化物对氮化铝瓷介电性能的影响(英文)

研究了添加Nd2O3和Er2O3对氮化铝陶瓷烧结性能、介电性能和显微结构的影响。结果表明:在氮化铝瓷中添加Nd2O3和Er2O3,有利于降低氮化铝陶瓷烧结温度,提高致密性,并且介电性能能够得到显著改善。添加3%(质量分数)Er2O3的AlN陶瓷的相对密度达98.8%,介电损耗为1.3×10-4,是纯AlN陶瓷的5%。其显微结构分析表明,氮化铝晶粒尺寸更均匀,并且其晶格参数更接近理论值,晶界相较少,从而使得其介电性能得到较大改善。     

润湿性对纳米多孔陶瓷膜输运性能的影响

为了实现复杂环境中高效回收水资源,采用先进的膜技术,基于建立的半连续超临界相反应改性实验装置对纳米多孔陶瓷膜分别进行亲水和疏水表面改性,通过接触角测量、微观结构观测等方法对润湿改性前后的纳米多孔陶瓷膜进行表征。基于单管管外水蒸气冷凝传热实验系统,对润湿改性前后的纳米多孔陶瓷膜进行了冷凝液输运特性的实验研究,揭示了混合气体温度、冷却水流速、跨膜压差和水蒸气体积分数等典型运行参数对纳米多孔陶瓷膜的冷凝液输运通量的影响规律与机理。同时,采用分子动力学方法,构建了水在不同润湿性纳米孔内输运模拟体系,研究水分子在不同润湿性纳米孔内的输运规律。     

FEM simulations of microstructure effects on thermoelastic properties of sintered ceramics

A model was developed to simulate macroscopic material properties of polycrystalline ceramics from the material properties of the constituting phases and the microstructure. Cubic and random structures were included. The model allows a variation of volume fractions of the phases, grain size and grain boundary areas. Representative for a large number of material properties, elastic tensor, thermal conductivity, coefficient of thermal expansion and thermal stress are calculated for individual microstructures using finite element methods (FEM). Simulations focus on two types of bi-continuous ceramic composites: zirconia toughened alumina (ZTA) and a porous zirconia ceramic which was infiltrated by a spinel-glass. Microstructure of experimental samples is represented by two different model structures: a Voronoi type structure for the ZTA ceramic and a cubic structure of cubes interconnected by cylinders for the infiltrated zirconia system. A substantial impact of microstructure on macroscopic material properties and internal stress distribution is obtained. A good agreement between measured and simulated material properties was found.     

Multiscale design of high‐voltage multilayer energy‐storage ceramic capacitors

Multilayer energy‐storage ceramic capacitors (MLESCCs) are studied by multiscale simulation methods. Electric field distribution of a selected area in a MLESCC is simulated at a macroscopic scale to analyze the effect of margin length on the breakdown strength of MLESCC using a finite element method. Phase field model is introduced to analyze the dielectric breakdown mechanism of MLESCC at a mesoscopic scale. The microstructure of selected area is generated through voronoi tessellation random construction routine containing core‐shell‐structured dielectric materials. The effects of margin length, shell permittivity, and shell volume fraction on the breakdown strength of MLESCC are respectively studied. Results indicate that the breakdown strength of MLESCC can be enhanced by adopting larger margin lengths, or by increasing the shell permittivity or volume fraction.