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The role and impact of 3D printing technologies in casting

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China Foundry 2017年第3期14卷 157-168页

作者： Jin-wu Kang Qiang-xian ma School of materials Science and Engineering Key Laboratory for Advanced Materials Processing Technology Tsinghua University Beoing 100084 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China

3D printing is such a magical technology that it extends into almost every sector relating to manufacturing, not to mention casting production. In this paper, the past, present and future of 3D printing in the foundry sector are profoundly reviewed. 3D printing has the potential to supplement or partially replace the casting method. Today, some castings can be directly printed by metal powders, for example, titanium alloys, nickel alloys and steel parts. Meanwhile, 3D printing has found an unique position in other casting aspects as well, such as printing the wax pattern, ceramic shell, sand core, sand mould, etc. Most importantly, 3D printing is not just a manufacturing method, it will also revolutionize the design of products, assemblies and parts, such as castings, patterns, cores, moulds and shells in casting production. The solid structure of castings and moulds will be redesigned in future into truss or spatially open and skeleton structures. This kind of revolution is just sprouting, but it will bring unimaginable impact on manufacturing including casting production. Nobody doubts the potential of 3D printing technologies in manufacturing, but they do have limitations and drawbacks.

关键词： 3D printing additive manufacturing rapid casting casting mould core design

Local PoincaréSymmetry in Gauge Theory of Gravity

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Communications in Theoretical Physics 2009年第5期51卷 843-844页

作者： ma Jian-Feng ma yong-Ge Department of Physics Beijing Normal University Beijing 100875 China

It is well known that the Poincaré gauge theories of gravity do not have the structure of a standard gauge theory. Nevertheless, we show that a general form of action for the gravitational gauge fields in the gauge t... 详细信息

关键词： Poincaré gauge theory translation invariance Lorentz invariance

SuperFusion: A Versatile Image Registration and Fusion Network with Semantic Awareness

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IEEE/CAA Journal of Automatica Sinica 2022年第12期9卷 2121-2137页

作者： Linfeng Tang Yuxin Deng yong ma Jun Huang Jiayi ma Electronic Information School Wuhan UniversityWuhan 430072China IEEE

Image fusion aims to integrate complementary information in source images to synthesize a fused image comprehensively characterizing the imaging scene. However, existing image fusion algorithms are only applicable to strictly aligned source images and cause severe artifacts in the fusion results when input images have slight shifts or deformations. In addition,the fusion results typically only have good visual effect, but neglect the semantic requirements of high-level vision *** study incorporates image registration, image fusion, and semantic requirements of high-level vision tasks into a single framework and proposes a novel image registration and fusion method, named Super Fusion. Specifically, we design a registration network to estimate bidirectional deformation fields to rectify geometric distortions of input images under the supervision of both photometric and end-point constraints. The registration and fusion are combined in a symmetric scheme, in which while mutual promotion can be achieved by optimizing the naive fusion loss, it is further enhanced by the mono-modal consistent constraint on symmetric fusion outputs. In addition, the image fusion network is equipped with the global spatial attention mechanism to achieve adaptive feature integration. Moreover, the semantic constraint based on the pre-trained segmentation model and Lovasz-Softmax loss is deployed to guide the fusion network to focus more on the semantic requirements of high-level vision tasks. Extensive experiments on image registration, image fusion,and semantic segmentation tasks demonstrate the superiority of our Super Fusion compared to the state-of-the-art *** source code and pre-trained model are publicly available at https://***/Linfeng-Tang/Super Fusion.

关键词： Global spatial attention image fusion image registration mutual promotion semantic awareness

Prediction of mechanical properties of cold rolled strip based on improved extreme random tree

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Journal of Iron and Steel Research International 2023年第2期30卷 293-304页

作者： Yun-bao Zhao yong Song Fei-fei Li xian-le Yan Institute of Engineering Technology University of Science and Technology BeijingBeijing100083China

Taking the 2130 cold rolling production line of a steel mill as the research object,feature dimensionality reduction and decoupling processing were realized by fusing random forest and factor analysis,which reduced the generation of weak decision trees while ensured its *** base learner used a weighted voting mechanism to replace the traditional average method,which improved the prediction ***,the analysis method of the correlation between steel grades was proposed to solve the problem of unstable prediction accuracy of multiple steel *** experimental results show that the improved prediction model of mechanical properties has high accuracy:the prediction accuracy of yield strength and tensile strength within the error of±20 MPa reaches 93.20%and 97.62%,respectively,and that of the elongation rate under the error of±5%has reached 96.60%.

关键词： Cold strip rolling Mechanical property prediction Extreme random tree Factor analysis Random forest Correlation analysis Steel grade

Some issues in diagnostics of solar chromospheric magnetic fields with the Mg b_2 line

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Research in Astronomy and Astrophysics 2014年第2期14卷 193-206页

作者： xian-yong Bai Yuan-yong Deng Jiang-Tao Su Guo-Ping Wang Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory of Space Weather Chinese Academy of Sciences

Up to now, exact measurements of chromospheric magnetic fields have not been as successful as those done in the photosphere. We are currently engaging in diagnostics of chromospheric magnetic fields with the Mg b2 line by employing the Multi-Channel Solar Telescope at Huairou Solar Observing Station. Therefore, how to improve accuracy in the measurement is the main issue of our present study. To this end, we first study linear calibration coefficients for longitudinal and transverse components of chromospheric fields, which vary with wavelength, in the case of a weak field assumption. Then the polarization crosstalk introduced by instruments is analyzed in detail with two numerical simulation methods. Comparisons of the po- larization signals between cases with and without correction are presented. The result indicates that polarization accuracy is greatly improved after crosstalk correction.

关键词： Sun: chromospheric -- magnetic fields -- spectral profiles: radiative transfer

Microstructure and hot flow stress at 970℃ of various heat-treated Ti2AlNb sheets

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Rare Metals 2020年第6期39卷 695-706页

作者： yong Wu Rong-Lei Fan xian-Jun Zhou Ming-He Chen College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The microstructure and hot tensile behaviors of the different heat-treated Ti2AlNb sheets were investigated by backscattered electron image(BSE),electron backscattering diffraction(EBSD),transmission electron microscope(TEM)and tensile *** grain sizes and contents ofα2,B2/βand O phases were quantitatively *** the heating time increases at 970℃,the mean grain size and content ofα2-phase *** grain shapes and distributions of the O-phase lamellar grains were affected by the heat *** plastic deformation promoted the O→B2/βphase transition and the globularization of O-phase lamellar grains at 970℃.Calculated by the creep equation and the iso-stress method,the grain size exponent wasμ=1.1 and the relationship between the material constants of B2/βand O phase was KO=1.14KB2/β.

关键词： Ti2AlNb alloy Heat treatment Tensile behaviors Microstructure evolution

The microRNA miR-184 regulates the CYP303A1 transcript level to control molting of Locusta migratoria

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Insect Science 2021年第4期28卷 941-951页

作者： Yan-Li Wang Li-xian Wu Hui-yong Li Xue-Qin Wen En-Bo ma Kun-Yan Zhu Jian-Zhen Zhang Research Institute of Applied Biology Shanxi UniversityTaiyuanShanxiChina College of Life Science Shanxi UniversityTaiyuanShanxiChina Department of Entomology Kansas State UniversityManhattanKSUSA

Cytochrome P450 monooxygenases(CYPs)play essential physiological functions in ***303A1 is highly conserved in insect species studied to date,and shows an indispensable role for adult eclosion in both Locusta migratoria and Drosophila ***,how CYP303A1 is regulated to control insect developmental processes remains *** this study,we discovered functional binding sites for miR-184 in the coding sequence of *** luciferase reporter assay showed that miR-184 could target LmCYP303A1 and regulate its expression in ***,overexpression of miR-184 through microinjection of agomir to locusts reduced the transcripts of LmCYP303A1 and led to abnormal molting,which is similar to the phenotype of silencing LmCYP303A1 by direct injection of dsLmCYP303A1 to ***,down-regulation of miR-184 by injection of antagomir increased the LmCYP303A1 transcript and caused molting *** findings suggested that miR-184 could target LmCYP303A1 to regulate the molting process in ***,which might be considered as a novel target for pest control.

关键词： CYP303A1 gene regulation insect molting Locusta migratoria miR-184

Phase thermal stability and mechanical properties analyses of(Cr,Fe,V)–(Ta,W)multiple-based elemental system using a compositional gradient film

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International Journal of Minerals,Metallurgy and materials 2020年第10期27卷 1379-1387页

作者： Qiu-wei Xing Jiang ma yong Zhang Beijing Advanced Innovation Center of materials Genome Engineering State Key Laboratory of Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronics Engineering College of Mechatronics and Control EngineeringShenzhen UniversityShenzhen 518060China

High-entropy alloys(HEAs)generally possess complex component combinations and abnormal *** traditional methods of investigating these alloys are becoming increasingly inefficient because of the unpredictable phase transformation and the combination of many *** development of compositionally complex materials such as HEAs requires high-throughput experimental methods,which involves preparing many samples in a short *** we apply the high-throughput method to investigate the phase evolution and mechanical properties of novel HEA film with the compositional gradient of(Cr,Fe,V)-(Ta,W).First,we deposited the compositional gradient film by ***,the mechanical properties and thermal stability of the(Cr0.33Fe0.33V0.33)x(Ta0.5W0.5)100−x(x=13-82)multiplebased-elemental(MBE)alloys were *** the deposited wafer was annealed at 600℃for 0.5 h,the initial amorphous phase was transformed into a body-centered cubic(bcc)structure phase when x=*** were observed on the film surface when x was 72 and ***,the highest hardness of as-deposited films was found when x=18,and the maximum hardness of annealed films was found when x=33.

关键词： high-throughput fabrication hard coating thermal resistance mechanical property phase stability high-entropy alloys

Mesoporous CeO_2 nanowires as recycled photocatalysts

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Science China Chemistry 2012年第7期55卷 1303-1307页

作者： SHAO Yue ma yong College of Chemistry Chemical Engineering and Food SafetyBohai UniversityJinzhou 121013China

Mesoporous CeO2 nanowires(NWs) were synthesized through a facile hydrothermal process by using triblock copolymer F127 as the *** analysis confirmed the cubic phase of the synthesized CeO2 ***-yield one-dimensional NWs with accessible mesopores could be observed from SEM and TEM images,and the surface area of the material was confirmed to be 273 m2 g-1 with pore width distribution of 6.9-13.8 *** mesoporous CeO2 NWs could be used as efficient photocatalysts for organic dye degradation under UV light irradiation,which was superior compared with commercial photocatalyst P-25 and commercial CeO2 *** NW structure facilitates the recovery of catalyst by sedimentation,leading to the impressive reusability of these mesoporous CeO2 NWs.

关键词： mesopore CeO2 NWs photocatalysis recycle