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Growth behavior of ultrafine austenite grains in microalloyed steel

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Acta Metallurgica Sinica(English Letters) 2009年第1期22卷 7-12页

作者： Linxiu DU Shengjie YAO Xianghua LIU guodong wang State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 China

Ultrafine austenite gains （UFAGs） with size of 1-5 μm were prepared through repetitive treatment, four times, of rapid heating and quenching, and the growth behaviors of these UFACs during both the reheating and cooling stages were investigated. The results indicated that UFAGs without pinning particles appeared with significant coarsening when the reheating temperature reached 1000 ℃. Although coarsening still occurred in the cooling stage, the growth was obscured during the isothermal holding process at temperatures between 900 ℃ and At3.

关键词： Ultrafine austenite grain Growth Microalloyed steel Second-phase particle

An improved theoretical procedure for the pore-size analysis of activated carbon by gas adsorption

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Chinese Journal of Chemical Engineering 2018年第3期26卷 551-559页

作者： guodong wang Jianchun Jiang Kang Sun Jianzhong Wu College of Chemical Engineering Nanjing Forestry University Department of Chemical and Environmental Engineering University of California Institute of Chemical Industry of Forest Products Chinese Academy of Forestry

Amorphous carbon materials play a vital role in adsorbed natural gas(ANG) storage. One of the key issues in the more prevalent use of ANG is the limited adsorption capacity, which is primarily determined by the porosity and surface characteristics of porous materials. To identify suitable adsorbents, we need a reliable computational tool for pore characterization and, subsequently, quantitative prediction of the adsorption behavior. Within the framework of adsorption integral equation(AIE), the pore-size distribution(PSD) is sensitive to the adopted theoretical models and numerical algorithms through isotherm fitting. In recent years, the classical density functional theory(DFT) has emerged as a common choice to describe adsorption isotherms for AIE kernel construction. However,rarely considered is the accuracy of the mean-field approximation(MFA) commonly used in commercial software. In this work, we calibrate four versions of DFT methods with grand canonical Monte Carlo(GCMC) molecular simulation for the adsorption of CH_4 and CO_2 gas in slit pores at 298 K with the pore width varying from 0.65 to 5.00 nm and pressure from 0.2 to 2.0 MPa. It is found that a weighted-density approximation proposed by Yu(WDA-Yu) is more accurate than MFA and other non-local DFT methods. In combination with the trapezoid discretization of AIE, the WDA-Yu method provides a faithful representation of experimental data, with the accuracy and stability improved by 90.0% and 91.2%, respectively, in comparison with the corresponding results from MFA for fitting CO_2 isotherms. In particular, those distributions in the feature pore width range(FPWR)are proved more representative for the pore-size analysis. The new theoretical procedure for pore characterization has also been tested with the methane adsorption capacity in seven activated carbon samples.

关键词： Non-local density functional theory Amorphous porous materials Pore size characterization Gas adsorption Adsorption integral equation

基于改进Yolov5的遥感影像多目标检测方法研究

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测绘与空间地理信息 2024年第7期47卷 142-145,149页

作者：王国栋马福生山东省国土测绘院山东济南250013

提出一种基于改进Yolov5的遥感影像目标检测方法,在骨干网络内增加高效通道注意力机制来提高对正样本特征的学习效率,在多尺度特征融合层内增加一个检测输出特征图,来提高对小目标的检测精度,采用带有梯度模长的交叉熵损失函数对模型进... 详细信息

提出一种基于改进Yolov5的遥感影像目标检测方法,在骨干网络内增加高效通道注意力机制来提高对正样本特征的学习效率,在多尺度特征融合层内增加一个检测输出特征图,来提高对小目标的检测精度,采用带有梯度模长的交叉熵损失函数对模型进行训练来缓解正负样本不平衡的问题。实验结果表明,本文所提出的改进方法在测试数据集上获得了较高的检测精度与很好的泛化能力,相比原始Yolov5有了显著提高,在测试环境下也能达到实时检测的水平。所提出的改进方法能够在资源调查、应急救援等领域具有很大的应用价值。

关键词：遥感影像 Yolov5 注意力机制损失函数

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中厚板回火炉低温均匀加热技术研发及应用

轧钢 2024年第1期41卷 75-78页

作者：李家栋叶世民李勇王昭东王国栋东北大学轧制技术及连轧自动化国家重点实验室辽宁沈阳110819

高强度中厚板是工程机械和重大工程领域的关键材料之一,中厚板回火炉是生产此类产品的重要装备。然而,常规低温回火加热技术温度波动大,无法满足此类产品低温回火工艺的高均匀性需求。为此,东北大学轧制技术及连轧自动化国家重点实验室... 详细信息

高强度中厚板是工程机械和重大工程领域的关键材料之一,中厚板回火炉是生产此类产品的重要装备。然而,常规低温回火加热技术温度波动大,无法满足此类产品低温回火工艺的高均匀性需求。为此,东北大学轧制技术及连轧自动化国家重点实验室研发出烟气循环式低温均匀加热回火炉技术装备。对该技术装备及其应用进行了介绍。实践表明:研发的中厚板回火炉低温均匀加热技术实现了±5℃的高均匀回火加热,解决了中厚板低温回火高均匀加热难题,为高强度中厚板回火和新工艺开发提供了重要保障。

关键词：高强度中厚板回火炉低温均匀加热低烟气排放

Grain Size Prediction after Continuous Cooling Transformation from Deformed Austenite to Ferrite

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Journal of Iron and Steel Research International 1998年第2期5卷 42-44页

作者： Qu Jinbo wang Zhaodong Liu Xianghua wang guodong Northeastern University

On the basis of transformation thermodynamics and kinetics theories,an algorithm for predicting ferrite grain size after continuous cooling transformation from deformed austenite to ferrite is *** calculated results of computer simulation with the algorithm are in so good agreement with the measured ones in controlled rolling and controlled cooling experiments that the theoretical algorithm is feasible.

关键词： ferrite grain size transformation kinetics continuous cooling deformed austenite

Isothermal Growth Kinetics of Ultra-fine Austenite Grains in a Nb-V-Ti Microalloyed Steel

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Journal of Materials Science & Technology 2009年第5期25卷 615-618页

作者： Shengjie Yao Linxiu Du Xianghua Liu guodong wang State Key Lab. of Rolling and Automation Northeastern University Shenyang 110004 China

Ultra-fine austenite grains with size of i-3 μm were prepared in a Nb-V-Ti steel through repetitive treatment of rapid heating and quenching. A model for the growth kinetics of these ultra-fine austenite grains was successfully created through successive 2 processes, and the activation energy Q for growth was estimated to be about 693.2 kJ/mol, which directly shows the inhibition effect of microalloy elements on the growth of ultra-fine austenite grains.

关键词： Ultra-fine austenite grain Grain growth kinetics Microalloyed steel

Microstructure and Mechanical Properties of Nb-B bearing Low Carbon Steel Plate: Ultrafast Cooling versus Accelerated Cooling

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Journal of Wuhan University of Technology(Materials Science) 2017年第3期32卷 619-624页

作者：王丙兴 DONG Fuzhi wang Zhaodong RDK Misra wang guodong State Key Laboratory of Rolling and Automation Northeastern University Laboratory for Excellence in Advanced Steel Research Center for Structural and Functional Materials Research and Innovation and Department of Metallurgical and Materials Engineering University of Texas at El Paso

The microstructure and mechanical properties of low carbon bainite high strength steel plate were studied via different cooling paths at the pilot scale. There was a significant increase in mechanical properties, and notably, the yield strength, tensile strength, and toughness at-40 ℃ for the tested steel processed by ultra-fast cooling were 126 MPa, 98 MPa and 69 J, respectively, in relation to steel processed by accelerated cooling. The ultra-fast cooling rate not only refined the microstructure, precipitates, and martensiteaustenite（M/A） islands, but also contributed to the refinement of microstructure in thick plates. The large size M/A constituents formed at lower cooling rate experienced stress concentration and were potential sites for crack initiation, which led to deterioration of low-temperature impact toughness. In contrast, the acicular ferrite and lath bainite with high fraction of high-angle grain boundaries were formed in steel processed by ultra-fast cooling, which retarded cleavage crack propagation.

关键词： TMCP ultra-fast cooling M/A constituent low-temperature toughness

Development and industrial application of ultra-fast cooling technology

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Science China(Technological Sciences) 2012年第6期55卷 1566-1571页

作者： TIAN Yong TANG Shuai wang BingXing wang ZhaoDong wang guodong State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

A new-generation TMCP(NG-TMCP) with ultra fast cooling(UFC) as core technique was suggested instead of the conventional TMCP in which some problems are to be *** the ultra fast cooling technology has been successfully applied to the plate rolling production in Shouqin Metal Materials *** trials are reported for the production of X70 pipeline steels(about 70000 t) under UFC *** steels with reasonably good properties have been produced on an industrial *** can improve the temperature uniformity,the mechanical properties and the plate profile of X70 pipeline *** performance features of the trial plates can meet the standard of X70 pipeline *** test results have shown that the qualification rate of shape control,the performance and charpy impact properties for the trial plates are 95%,97% and 98%,*** impact values of X70 pipeline steel at UFC mode exceed the standard requirements of X80 pipeline *** productivity is enhanced because cutting quantity of head and tail of the plate is *** enhancement of control accuracy of the red back temperatures is favorable for industrial production of X70 pipeline *** reduced production of the steel-making has been industrially achieved,since a new composition was designed by reducing the vanadium content to less than 0.045 wt.%.

关键词： pipeline steel ultra fast cooling the reduced production plate

Thermodynamic Calculations of Composition of Carbide and Nitride Precipitates and Precipitation Order in Multi-Microalloyed Steels

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Journal of Iron and Steel Research International 1998年第1期5卷 38-41页

作者： Qu Jinbo wang Zhaodong Liu Xianghua wang guodong Northeastern University

By means of regular solution sublattice model,the mole fraction and composition of complex carbide and nitride precipitates in Nb-Ti-V microalloyed steels are calculated *** prediction of precipitation order of carbides and nitrides in complex precipitates is performed according to the calculated results at various austenitizing *** calculation can provide thermodynamic basis for quantitative prediction of complex precipitation behavior in NbTi-V-containing steels.

关键词： carbide nitride precipitation order microalloyed steel