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Cellular automata modelling of grain coarsening during reheating——Ⅱ. Abnormal grain growth

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journal of University of Science and Technology Beijing 2005年第1期12卷 26-32页

作者： WanhuaYu e.j.palmiere S.P.Banks jingtaoHan DepartmentofMaterialsengineering UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofengineeringMaterials UniversityofSheffieldS13JDSheffieldUK DepartmentofAutomaticControlandSystemsengineering UniversityofSheffieldS13JDSheffieldUK

The 2-dimensional cellular automata (CA) simulation technique has been utilized to investigate the abnormal grain coarsening. The growth of abnormal grains is modelled under this assumption that different grains have different boundary energies and boundary mobilities. As temperature increases, some grains may first get rid of the particle pinning effect. Thus a high probability is obtained for atoms to jump over the boundary, so that they can consume other primary retained grains quickly. From the simulation, the characteristics of the abnormal grain coarsening under different conditions are demonstrated successfully. An experiment has also been carried out to reflect the abnormal grain coarsening on the microalloy steel. Simulation results are quite close to the experimental evidence.

关键词： computer simulation grain growth microstructure reheating

Multi-Pass Simulation of Heavy Plate Rolling Including Intermediate Forced Cooling

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journal of Iron and Steel Research International 2011年第S1期18卷 506-510页

作者： e.j.palmiere A.A.Howe H.C.Carey Institute for Microstructural and Mechanical Process engineering:The University of Sheffield (IMMPeTUS) Sir Robert Hadfield BuildingMappin StreetSheffieldS1 3JDUK Tata Steel Research Development &Technology Swinden Technology CentreMoorgateRotherham S60 3ARUK

Thermomechanical Controlled Processing (TMCP) including accelerated cooling after the final hot rolling pass is a well-established technology,widely applied in HSLA steel plate ***,there are still certain limitations,especially for thicker *** rolling schedule includes a long holding period (HP) after the roughing stage to allow the temperature to fall sufficiently for optimised TMCP during *** Forced Cooling (IFC) applied during the HP can increase productivity by decreasing the required hold time,can restrict austenite grain growth,and can also improve the subsequent strain penetration in thick plate with further metallurgical ***-pass plane strain compression (PSC) tests have been performed on the thermomechanical compression (TMC) machine at Sheffield University including different severities of *** it is impossible to simulate all aspects of the temperature and strain gradients present in thick plates in laboratory specimens,and most of the tests were conducted at temperatures and strains calculated by Finite element modelling as relevant to specific positions through the plate ***,some aspects of the gradients were addressed with tests using cold *** results have indeed shown that IFC can shorten the HP and reduce austenite grain growth and its variation across thick plate.

关键词： Steel plate rolling intermediate forced cooling plane strain compression recrystallisation grain growth finite element modelling temperature and strain distribution

CeLLULAR AUTOMATA MODeLLING OF GRAIN COARSeNING DURING ReHeATING AND VALIDATION WITH THe eXPeRIMeNTAL ReSULTS

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Acta Metallurgica Sinica(english Letters) 2005年第2期18卷 113-120页

作者： W.H.Yu e.j.palmiere S.P.Banks j.T.Han SchoolofMaterialsScienceandengineering UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofengineeringMaterials UniversityofSheffieldSheffieldS13JDUK DepartmentofAutomaticControlandSystemsengineering UniversityofSheffieldSheffieldS13J-DUK

A novel 2D cellular automata (CA) model has been developed for description of normal grain coarsening and abnormal grain coarsening process. The program reflects the grain coarsening quite well even through the average grain size becomes very large. Follow results have been obtained: (a) The model reflect the normal grain growth kinetics gradually increase with probability and grain growth speed can be controlled. Based on this result, temperature can be coupled in the model. (b) Abnormal grain growth is modelled successfully. (c) Methodology has been put forward to find the relationship between the experiment results and modelling results. The experimental work on the grain coarsening has been carried out. Graphical output matched the realistic microstructure in every detail. Because many physical parameters can be taken into account in the CA programme, this CA model could not only qualitatively demonstrate the grain growth process, but also quantitatively predict and analyse the grain coarsening process.

关键词： computer simulation grain growth microstructure reheating

The Use of a Fe-30%Ni and Fe-30%Ni-Nb Alloy as a Model Systems for Studying the Microstructural evolution during the Hot Deformation of Austenite

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The Use of a Fe-30%Ni and Fe-30%Ni-Nb Alloy as a Model Syste...

技术创新与循环经济——第二届宝钢学术年会

作者： W.M.RAINFORTH P.CIZeK F.BAI R.POTHS e.j.palmiere IMMPeTUS:Institute for Microstructural and Mechanical Process engineering:The University of Sheffield Sheffield S1 3JDUnited Kingdom

＜正＞The development of physically-based models of microstructural evolution during thermomechanical processing of metallic materials requires knowledge of the internal state variable data,such as microstructure, texture and dislocation substructure characteristics,over a range of processing *** is a particular problem for steels,where transformation of the austenite to a variety of transformation products eradicates the hot deformed *** paper reports on a model Fe-30%Ni based alloy,which retains a stable austenitic structure at room temperature,and has therefore been used to model the development of austenite microstructure during hot deformation of conventional low carbon-manganese *** also provides an excellent model alloy system for microalloy *** of the microstructure and crystallographic texture was characterised in detail using optical microscopy,XRD,SeM,eBSD,and *** dislocation substructure has been quantified as a function of crystallographic texture component for a variety of deformation conditions for the Fe-30%Ni base *** extension to this study,as the use of a microalloyed Fe-30%Ni-Nb alloy in which the strain induced precipitation mechanism was studied *** work has shown that precipitation can occur at a much finer scale and higher number density than hitherto considered,but that pipe diffusion leads to rapid *** implications of this for model development are discussed.

关键词： microalloyed steels strain induced precipitation microbands texture

来源： cnki会议评论

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cnki会议

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加工条件对管线钢组织影响的实验研究

中国冶金 2007年第5期17卷 37-40页

作者：杨雄飞 e.j.palmiere 付俊岩中信金属公司微合金化技术中心北京100004 谢菲尔德大学IMMPeTUS研究所

管线钢的最终组织和性能与控轧工艺以及加速冷却直接相关。采用一种新型的模拟轧制过程设备来研究X70级别管线钢在热变形冷却后的组织;设计了一系列的平面应变压缩实验来模拟板带轧制过程参数特别是精轧温度和冷却速率对最终组织的影响... 详细信息

管线钢的最终组织和性能与控轧工艺以及加速冷却直接相关。采用一种新型的模拟轧制过程设备来研究X70级别管线钢在热变形冷却后的组织;设计了一系列的平面应变压缩实验来模拟板带轧制过程参数特别是精轧温度和冷却速率对最终组织的影响。采用恒定的变形速度70 s-1以及恒定的道次间隙时间,在850、900、950℃温度下的单道次和多道次压缩变形,随后研究2种不同冷却速率(3℃/s,6℃/s)获得的最终微观组织。观察发现,对于950、900、850℃的变温变形,出现了严重的混晶现象,而850℃下进行的3次压缩试样在6℃/s冷却到660℃后铁素体晶粒尺寸达到4.3μm。

关键词：平面应变压管线钢应力-应变曲线晶粒

NeCAB family of neuronal calcium-binding proteins in health and disease

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Neural Regeneration Research 2025年第5期20卷 1236-1243页

作者： Diones Bueno Michael K.e.Schafer Sudena Wang Michael j.Schmeisser Axel Methner Institute for Molecular Medicine University Medical Center of the Johannes Gutenberg-UniversityMainzGermany Department of Anesthesiology University Medical Center of the Johannes Gutenberg-UniversityMainzGermany Institute of Anatomy University Medical Center of the Johannes Gutenberg-UniversityMainzGermany

The N-terminal eF-hand calcium-binding proteins 1–3(NeCAB1–3) constitute a family of predominantly neuronal proteins characterized by the presence of at least one eF-hand calcium-binding domain and a functionally less well characterized C-terminal antibiotic biosynthesis monooxygenase domain. All three family members were initially discovered due to their interactions with other proteins. NeCAB1 associates with synaptotagmin-1, a critical neuronal protein involved in membrane trafficking and synaptic vesicle exocytosis. NeCAB2 interacts with predominantly striatal G-protein-coupled receptors, while NeCAB3 partners with amyloid-β A4 precursor protein-binding family A members 2 and 3, key regulators of amyloid-β production. This demonstrates the capacity of the family for interactions with various classes of proteins. NeCAB proteins exhibit distinct subcellular localizations: NeCAB1 is found in the nucleus and cytosol, NeCAB2 resides in endosomes and the plasma membrane, and NeCAB3 is present in the endoplasmic reticulum and Golgi apparatus. The antibiotic biosynthesis monooxygenase domain, an evolutionarily ancient component, is akin to atypical heme oxygenases in prokaryotes but is not wellcharacterized in vertebrates. Prokaryotic antibiotic biosynthesis monooxygenase domains typically form dimers, suggesting that calcium-mediated conformational changes in NeCAB proteins may induce antibiotic biosynthesis monooxygenase domain dimerization, potentially activating some enzymatic properties. However, the substrate for this enzymatic activity remains uncertain. Alternatively, calcium-mediated conformational changes might influence protein interactions or the subcellular localization of NeCAB proteins by controlling the availability of protein–protein interaction domains situated between the eF hands and the antibiotic biosynthesis monooxygenase domain. This review summarizes what is known about genomic organization, tissue expression, intracellular localization, interac

关键词： calcium eF hand mitochondria nervous system signal transduction

Hybrid silicon modulators

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Chinese Optics Letters 2009年第4期7卷 280-285页

作者： j.e.Bowers Department of electrical and Computer engineering University of California Santa Barbara

A number of active elements have been demonstrated using the hybrid silicon evanescent platform, including lasers, amplifiers, and detectors. In this letter, two types of hybrid silicon modulators, flflfilling the building blocks in optical communication on this platform, are presented. A hybrid silicon electroabsorp- tion modulator, suitable for high speed interconnects, with 10-dB extinction ratio at -5 V and 16-GHz modulation bandwidth is demonstrated. In addition, a hybrid silicon Mach-Zehnder modulator utilizing carrier depletion in multiple quantum wells is proved with 2 *** voltage-length product, 150-nm optical bandwidth, and a large signal modulation up to 10 Gb/s.

关键词： Bandwidth electroabsorption modulators Modulation Modulators Optical communication Quantum well lasers Semiconducting indium compounds Semiconductor quantum wells Silicon Silicon detectors

Approximate ballistics formulas for spherical pellets in free flight

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Defence Technology（防务技术） 2018年第1期14卷 1-11页

作者： e.j.Allen Department of Mathematics and Statistics Texas Tech University

The ballistics equations for spherical pellets in free flight are simplified through appropriate scaling of the pellet velocity and pellet distance. Two different drag coefficient curves are averaged to yield a single curve applicable to shot pellets and round balls. The resulting S-shaped drag coefficient curve is approximated by three straight-line segments. The scaled ballistics equations are then solved exactly and simple formulas are found for the velocity and flight time with respect to trajectory distance. The formulas are applicable to spherical shot pellets and round balls of any composition under any atmospheric conditions. The formulas are amenable to quick and easy computation and may also serve as an aid in understanding and comparing black-box ballistics calculators. For shotshell ballistics, an important assumption in the present investigation is that the pellets are moving as single, free spheres and not as a dense cloud or in a shot column, in particular, the pellets are not interacting during flight. Therefore, the formulas are most appropriate for single round balls, for large shot sizes, and for pellets of small shot size fired from open chokes. The formulas are clear and accessible, and can be implemented by military or law enforcement personnel as well as hunters and shooters. This work differs from previous investigations in that accurate ballistics formulas are derived for spherical projectiles of shotguns and muzzleloaders using realistic drag coefficients.

关键词： Ballistics Sphere Drag Shotgun Muzzleloader Nondimensionalization

Are hydrides under high-pressure-high-temperature superconductors?

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National Science Review 2024年第7期11卷 9-12页

作者： j.e.Hirsch Department of Physics University of California

Contrary to the current consensus, I argue that the existing evidence for high-temperature superconductivity in hydrides under high pressure is not compelling. I suggest that the focus of the field should urgently shift to establish unequivocally experimentally whether or not superconductivity in pressurized hydrides exists, instead of continuing to search for new materials that might show elusive signals of unproven superconductivity at ever higher temperatures. The implications of a negative finding for the theoretical understanding of superconductivity are discussed.

关键词： Hydrides