Electromagnetic torque detecting for optimization of in-mould electromagnetic stirring in the billet and bloom continuous casting

ABSTRACT

In this paper, an electromagnetic torque device based on the theoretical model was established to determine the optimum frequency accurately and conveniently in billet and bloom continuous casting with in-mould electromagnetic stirring (M-EMS). Magnetic characteristics with M-EMS was investigated by numerical simulation and physical experiment with the application of electromagnetic torque device and gauss meter. In addition, the effects of stirring frequency with M-EMS on macro segregation and equiaxed crystal ratio were compared and analysed for 55SiCr with 150?mm?×?150?mm billet caster and BU with 310?×?360?mm bloom caster by a series of plant trials, respectively. The results showed that maximum magnetic flux density and maximum electromagnetic torque occurred with different frequency and same current in M-EMS, and central equiaxed crystal ratio and macro segregation has been significantly improved by optimum frequency with M-EMS.     

微覆盖解决高低层混合居民楼深度覆盖的应用

城区高低层混合居民楼区域作为无线网络覆盖难点,传统宏站无法进行有效的覆盖。本文通过采用“微覆盖、微对打”的建设方式有效解决“高低层混合居民楼”无线网络信号的深度覆盖问题。     

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

In this study, gradual and sudden reduction methods were combined to simulate a progressive failure in notched composite plates using a macro mechanics approach. Using the presented method, a progressive failure is simulated based on a linear softening law prior to a catastrophic failure, and thereafter, sudden reduction methods are employed for modeling a progressive failure. This combination method significantly reduces the computational cost and is also capable of simultaneously predicting the first and last ply failures (LPFs) in composite plates. The proposed method is intended to predict the first ply failure (FPF), LPF, and dominant failure modes of carbon/epoxy and glass/epoxy notched composite plates. In addition, the effects of mechanical properties and different stacking sequences on the propagation of damage in notched composite plates were studied. The results of the presented method were compared with experimental data previously reported in the literature. By comparing the numerical and experimental data, it is revealed that the proposed method can accurately simulate the failure propagation in notched composite plates at a low computational cost.     

基于损伤力学的岩体宏观力学参数研究

根据脆性材料研究的成果 ,采用自洽理论建立了岩体的损伤力学模型 ,该模型能够通过岩块和结构面的性质反映整个岩体的力学性质。采用所建立的损伤力学模型 ,结合岩体现场试验的要求 ,提出了岩体现场力学试验的计算机模拟方法 ,并用该方法对某核电站的核岛区岩体宏观力学参数进行了模拟 ,结果表明该文的方法能够解决实际工程中所遇到的岩体宏观力学参数难以确定的问题     

可选性曲线绘制自动化的实现

以可选性曲线绘制为例,介绍了应用Excel的宏录制功能编制VBA程序和对Excel进行选矿专业功能扩展的方法,以真正实现选煤试验数据处理自动化。     

基于插铣法和宏程序的矩形腔铣削

分析了插铣法的特点和用途,指出了插铣法加工矩形腔的宏程序编制过程。利用插铣法和宏程序进行矩形腔铣削,大大节省了数控加工时间,对数控机床加工功能的扩充起了很大作用。     

有序合金Ni3Si脆性改善研究进展

从微合金化，宏合金化，细化晶粒3个方面介绍改善Ni3Si合金脆性的研究进展。微合金化虽可提高Ni3Si的室温韧性，但效果并不明显，而宏合金化虽可在一定温度范围内提高Ni3Si合金韧性，有些元素降低高温韧性或室温韧性；细化晶粒提高Ni3Si韧性的效果产不明显。合金成分富Ni化，多元素宏合金化与微合金化相结合是改善Ni3Si有序合金脆性的最佳方法。     

BP网络在消防训练评价模型中的应用

对如何评价现代消防训练的总体效果，从被评单位的基本情况、训练工作的指导思想等9个方面，建立了评价指标体系原则、目标和内容。通过引入人工神经网络理论，建立了基于BP网络的评价模型，并结合应用实例进行了讨论。     

房地产市场土地供应时滞效应分析

土地供应时滞效应是关系到土地宏观调控实施效果的重要问题。本文分析了土地供应时滞在微观项目和宏观市场两个层面的表现,并利用相关分析、分布滞后模型等计量工具对南京市土地供应的时滞效应进行了实证分析,得出的结果较好地揭示了南京市房地产市场中土地供应的时滞效应,可以为土地调控决策提供科学合理的支持。