快速付里叶变换在板形检测中的应用

本文简述了付里叶变换原理及其快速算法在板形检测信号处理中的应用.通过在自行研制的动态板形检测模拟试验装置上测量板带的振动信息,采用快速付里叶变换对其进行频谱分析,获得板形缺陷信息,并将分析所得结果与剖条试验中实测的板带实际板形状况对比,两者对比结果是一致的、吻合的,从而为板形检测提供了一种新方法.     

解析板形刚度理论的实验验证

解析板形刚度理论是板形理论研究的重大进展,是具有我国独立知识产权的研究成果。文章通过在四辊实验轧机上冷轧铝板的方法,对解析板形刚度理论所建立的板形向量测控模型进行了验证,研究结果证明了该理论的正确性。该理论可用于板带轧制过程板形的预测、设定和控制,消除和减少板带轧制中波浪和翘曲等缺陷,并实现板凸度的自由控制。     

平直度表示方法I及其与波浪度λ的关系

众所周知 ,板带材板形不良的原因是由于板带材宽度上的各点延伸不均。为了更正确地表达平直度 ,采用板带材横向各点的相对长度差ΔＬ/Ｌ来表示板形 ,其中Ｌ是所取基准点的轧后长度 ,ΔＬ是其他点相对于基准点的轧后长度差。相对长度差也称板形系数 ρ ,ρ=ΔＬ/Ｌ。加拿大铝公司将横向上最长和最短纵条之间的相对延伸差作为板形单位 ,称作Ｉ单位 ,一个Ｉ单位相当于相对长度差的 1 0 - 5。所以板形ΣＳｔ为 :ΣＳｔ =1 0 - 5(ΔＬＬ ) (1 )　　目前国际上对板带材平直度的表示方法已通用Ｉ单位。在表示平直度的方法中 ,过去大多数用波浪度或…     

板带板形与横向厚度分布关系探讨

分析了板带板形与板带横向厚度分布之间的关系、板坯状况对板形的影响     

宽带钢热连轧机的板形控制

热连轧机的板形控制一直是国内外研究的难点和热点,先进的板形控制系统是保证板带综合质量的前提。文章针对热轧板带的生产特点,主要介绍了板形控制系统中的板形控制技术,即板形检测技术、板形调控手段和板形控制模型。板形检测技术主要介绍基于辐射吸收测量的非接触式凸度仪和基于激光三角法的非接触式平坦度检测仪。板形调控手段主要介绍液压弯辊技术、液压窜辊技术和层流冷却技术。板形控制模型主要介绍板形板厚综合控制系统的系统模型功能模块。     

DSR平整机板形控制能力分析

由于板带材是钢铁行业的主干产品,板形控制是板带轧机的关键技术,平整是提高板形精度的重要手段,平整机的板形控制能力直接影响到成品板带材的板形质量。利用建立的理论模型对DSR平整机各板形控制机构的板形调控功效进行了研究。计算了不同宽度下弯辊力及各压块力的板形调控功效曲线,为DSR技术的在线控制和设定提供了理论依据。     

板宽对轧机刚度影响的实验研究

轧机的横向刚度和纵向刚度对于板带轧制而言非常重要,横向刚度直接决定着轧出的板形是否良好,纵向刚度对于板带纵向厚度控制具有重要意义。然而以往学者对于轧机刚度的研究大多停留在理论计算和数值模拟上,缺乏实验的支撑,因此本文主要通过实验的方法,在350 mm四辊可逆冷轧机上轧制不同宽度的工业纯铝板,研究了轧件宽度对轧机纵向刚度及轧机横向刚度的影响规律。并且在研究宽度的影响因素之前,首先研究了轧制速度对刚度的影响,并取得最优轧制速度,在最佳轧制速度下进行实验研究,实验结果显示板带轧制在速度较低并轧制和辊身相近宽度规格的板材时,所获得的厚度精度最高,板形最为良好。所得结论为得到良好的板形及厚度的精确控制具有基础性指导意义。     

支承辊倒角对板形控制的研究

支承辊倒角是板带轧制过程中常用于板形控制的一种方法,目前关于这方面研究的报道很少。通过简支梁模型以及有限元模型分析研究了宽度为400 mm的铜带轧制生产中支承辊倒角对轧制板带板形控制的影响。简支梁模型分析显示,若倒角后支承辊辊面长度大于板带宽度,则其长度越小,对板形控制越有利;有限元模型结果显示,倒角后支承辊辊面长度小于460 mm时,轧板肋部将产生应力集中,易出现肋浪缺陷。因此,倒角后支承辊辊面长度的设定应综合考虑支承辊倒角对板形控制的有利作用及倒角后支承辊辊面长度过小时造成轧板肋部出现应力集中的问题,取最优值。     

轧辊轴移轧机的基本特性研究

随着对高质量板带材需求的增加,对板带产品的尺寸和断面的控制技术的要求也越来越高了。板形和断面控制技术在过去20年里已取得迅速进展,在所有的板形和断面控制技术中,轧辊轴向移动已被证明是最有效的控制板形断面和边部减薄的技术之一。     

板带平直度的意义与度量

阐述板形的意义，分析板带不良板形产生的原因，介绍各国评估板形优劣的不同方法与其相互关系，并用数学推导法，揭示Ｉ单位的来历，以及Ｉ单位在现代铝板带生产中的实际意义。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.