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无间隙原子钢高压扭转过程中塑性变形的滞后性研究

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中国科学：技术科学 2018年第2期48卷 154-160页

作者：宋月鹏张紫涵高东升陈苗苗李法德 kim hyoung-seop 山东农业大学机械与电子工程学院泰安271018 山东农业大学园艺科学与工程学院泰安271018 韩国浦项工科大学材料科学与工程学院韩国浦项790784

采用DEFORM-3D有限元分析软件,对无间隙原子钢(IF钢)在高压扭转(HPT)中的扭转阶段大塑性变形(SPD)过程进行模拟仿真,通过分析试样的等效应变分布,得到了IF钢在不同剖面的变形滞后性特征.结果表明,在扭转的前期阶段(不大于2周),IF钢试样... 详细信息

采用DEFORM-3D有限元分析软件,对无间隙原子钢(IF钢)在高压扭转(HPT)中的扭转阶段大塑性变形(SPD)过程进行模拟仿真,通过分析试样的等效应变分布,得到了IF钢在不同剖面的变形滞后性特征.结果表明,在扭转的前期阶段(不大于2周),IF钢试样表现出大塑性变形的滞后性:试样边缘的等效应变值明显高于心部,且沿径向由边缘到心部数值逐渐变小;与试样的上表面相比,下表面的等效应变明显较高,边缘大塑性变形区域较大,并且随着旋转角度、距心部距离的增加,上表面大塑性变形的滞后性越来越明显.这说明在扭转的前期阶段,试样的中心部及上表面的塑性变形相对滞后,并对其原因进行了初步分析,这与其下模旋转及表面摩擦密切相关,理论分析、显微组织及硬度检测结果均验证了该模拟结果的可靠性.

关键词：无间隙原子钢高压扭转大塑性变形滞后性有限元分析

化学炉燃烧合成Al4SiC4粉体的绝热燃烧温度计算与实验研究

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硅酸盐学报 2011年第8期39卷 1323-1328页

作者：李学超宋月鹏李江涛陈义祥 LEE Chong SOO kim hyoung seop 山东农业大学机械与电子工程学院山东泰安271018 Department of Materials Science and Engineering Pohang University of Science and Technology Pohang 790-784 Korea 中国科学院理化技术研究所北京100190

根据热力学基本原理,采用计算机数值计算,对化学炉燃烧合成的铝碳化硅(Al4SiC4)粉体的绝热燃烧温度进行数值计算。结果表明:常温下Al–Si–C体系的绝热燃烧温度仅为1 300 K;只有当预热温度在930 K以上时,才可以实现自蔓延燃烧。Al–Si–... 详细信息

根据热力学基本原理,采用计算机数值计算,对化学炉燃烧合成的铝碳化硅(Al4SiC4)粉体的绝热燃烧温度进行数值计算。结果表明:常温下Al–Si–C体系的绝热燃烧温度仅为1 300 K;只有当预热温度在930 K以上时,才可以实现自蔓延燃烧。Al–Si–C体系的燃烧合成将分步进行,首先生成中间产物Al4C3和SiC,而后由其形成最终产物Al4SiC4。通过体系中添加过量石墨,利用Ti–Si体系化学炉,燃烧合成出粒度均匀且纯度较高的Al4SiC4粉体,根据实验检测并结合绝热燃烧温度计算结果,分析了石墨过量对产物Al4SiC4粉体纯度的影响。

关键词：铝碳化硅粉体绝热燃烧温度化学炉燃烧合成

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高压扭转IF钢压缩阶段的不均匀变形

材料热处理学报 2017年第2期38卷 105-110页

作者：宋月鹏陈苗苗徐保岩高东升郭晶许令峰 kim hyoung-seop 山东农业大学机械与电子工程学院山东泰安271018 山东农业大学园艺科学与工程学院山东泰安271018 韩国浦项工科大学韩国浦项790784

观察并研究了IF钢高压扭转压缩阶段过程中的硬度及显微组织不均匀分布特征,并利用ANSYS有限元分析软件对实验结果进行模拟仿真验证。结果表明IF钢在高压扭转压缩阶段过程中的应力、应变及硬度分布是不均匀的:心部变形程度较小,硬度比较... 详细信息

观察并研究了IF钢高压扭转压缩阶段过程中的硬度及显微组织不均匀分布特征,并利用ANSYS有限元分析软件对实验结果进行模拟仿真验证。结果表明IF钢在高压扭转压缩阶段过程中的应力、应变及硬度分布是不均匀的:心部变形程度较小,硬度比较低;中间区域变形比较均匀,硬度也趋于一致;在边缘区域,形变程度很大,从而硬度比较高;对于限定型高压扭转,由于模具凹槽立壁对试样变形的阻滞作用,变形量较小从而形成形变"死区"。模拟结果与硬度及显微组织分布的实验结果极为吻合,由此说明,正是由于压缩阶段试样各部位不均匀变形导致了显微组织、硬度的不均匀分布。

关键词：高压扭转压缩阶段 IF钢不均匀变形有限元分析

Functionally graded structure of a nitride-strengthened Mg_(2)Si-based hybrid composite

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Journal of Magnesium and Alloys 2024年第3期12卷 1239-1256页

作者： Jeongho Yang Woongbeom Heogh Hogi Ju Sukhyun Kang Tae-Sik Jang Hyun-Do Jung Mohammad Jahazi Seung Chul Han Seong Je Park hyoung seop kim Susmita Bose Amit Bandyopadhyay Martin Byung-Guk Jun Young Won kim Dae-kyeom kim Rigoberto CAdvincula Clodualdo Aranas Jr Sang Hoon kim School of Mechanical Engineering Pusan National UniversityBusan 46241Republic of Korea Department of Mechanical Design Engineering Hanyang UniversitySeoul 04763Republic of Korea Process Research 3 Team LG Display Co.Ltd.PajuGyeonggi-do 10845Republic of Korea Department of Materials Science and Engineering Chosun UniversityGwangju 61452Republic of Korea Institute of Well-Aging Medicare&Chosun University LAMP Center Chosun UniversityGwangju 61452Republic of Korea Division of Materials Science and Engineering Hanyang UniversitySeoul 04763Republic of Korea Department of Mechanical Engineering École de Technologie SupérieureMontrealQuebec H3C 1K3Canada Material&Component Convergence R&D Center Korea Construction Equipment Technology InstituteGunsanJeollabuk-do 54002Republic of Korea School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore Graduate Institute of Ferrous&Eco Materials Technology Pohang University of Science and TechnologyPohangGyeongsangbuk-do 37673Republic of Korea Advanced Institute for Materials Research Tohoku UniversitySendai 980-8577Japan Institute for Convergence Research and Education in Advanced Technology Yonsei UniversitySeoul 03722Republic of Korea School of Mechanical and Materials Engineering Washington State UniversityPullmanWashington 99164USA School of Mechanical Engineering Purdue UniversityWest LafayetteIndiana 47907USA Research Institute of Advanced Manufacturing Technology Korea Institute of Industrial TechnologyIncheon 21999Republic of Korea Department of Macromolecular Science and Engineering Case Western Reserve UniversityClevelandOhio 44106USA Department of Chemical and Biomolecular Engineering and Joint Institute for Advanced Materials University of TennesseeKnoxvilleTennessee 37996USA Center for Nanophase Materials and Sciences Oak Ridge National LaboratoryOak RidgeTennessee 37830USA Department of Mechanical Engineering University of New BrunswickFrederictonNew Brunswick E3B 5A3Cana

The ex-situ incorporation of the secondary SiC reinforcement,along with the in-situ incorporation of the tertiary and quaternary Mg_(3)N_(2) and Si_(3)N_(4) phases,in the primary matrix of Mg_(2)Si is employed in order to provide ultimate wear resistance based on the laser-irradiation-induced inclusion of N_(2) gas during laser powder bed *** is substantialized based on both the thermal diffusion-and chemical reactionbased metallurgy of the Mg_(2)Si–SiC/nitride hybrid *** study also proposes a functional platform for systematically modulating a functionally graded structure and modeling build-direction-dependent architectonics during additive *** strategy enables the development of a compositional gradient from the center to the edge of each melt pool of the Mg_(2)Si–SiC/nitride hybrid ***,the coefficient of friction of the hybrid composite exhibits a 309.3%decrease to–1.67 compared to–0.54 for the conventional nonreinforced Mg_(2)Si structure,while the tensile strength exhibits a 171.3%increase to 831.5 MPa compared to 485.3 MPa for the conventional *** outstanding mechanical behavior is due to the(1)the complementary and synergistic reinforcement effects of the SiC and nitride compounds,each of which possesses an intrinsically high hardness,and(2)the strong adhesion of these compounds to the Mg_(2)Si matrix despite their small sizes and low concentrations.

关键词： Laser powder bed fusion Mg_(2)Si-SiC/nitride hybrid composite Both the thermal diffusion-and chemical reaction-based metallurgy Functionally graded structure Compositional gradient Wear resistance.

IF钢高压扭转过程中不均匀塑变特征的仿真模拟

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材料热处理学报 2018年第9期39卷 120-124,130页

作者：张紫涵宋月鹏高东升张红梅耿晓阳 kim hyoung-seop 山东农业大学机械与电子工程学院山东省园艺机械与装备重点实验室山东泰安271018 山东农业大学园艺科学与工程学院山东泰安271018 韩国浦项工科大学材料科学与工程学院韩国浦项790784

采用有限元软件DEFORM-3D对IF钢试样高压扭转过程进行计算机仿真模拟,研究高压扭转试样不均匀塑性变形特征,对硬度和显微组织分布进行研究。结果表明：试样在进行高压扭转两个阶段（压缩、扭转）的过程中,均发生了显著的不均匀塑性变形... 详细信息

采用有限元软件DEFORM-3D对IF钢试样高压扭转过程进行计算机仿真模拟,研究高压扭转试样不均匀塑性变形特征,对硬度和显微组织分布进行研究。结果表明：试样在进行高压扭转两个阶段（压缩、扭转）的过程中,均发生了显著的不均匀塑性变形,在扭转初期阶段,其不均匀变形程度尤其显著;在试样径向,IF钢试样的塑性变形程度从中部到边缘逐步增大;在试样的轴向,试样的塑性变形程度随距试样下表面距离的增加而逐渐减小;硬度分布和显微组织检测结果均验证了模拟结果的可靠性。

关键词： IF钢高压扭转计算机数值模拟不均匀塑性变形

Absence of enhancement in a lesion does not preclude primary central nervous system T-cell lymphoma:A case report

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World Journal of Clinical Cases 2024年第2期12卷 374-382页

作者： Chan-seop kim Chi-Hoon Choi Kyung Sik Yi Yook kim Jisun Lee Chang Gok Woo Young Hun Jeon Department of Radiology Chungbuk National University HospitalChungbuk National University College of MedicineCheongju-si 28644Chungcheongbuk-doSouth Korea Department of Pathology Chungbuk National University HospitalChungbuk National University College of MedicineCheongju-si 28644Chungcheongbuk-doSouth Korea Department of Radiology Seoul National University HosptialSeoul 03080South Korea

BACKGROUND Primary central nervous system lymphoma(PCNSL)is a non-Hodgkin lymphoma that originates in the central nervous system(CNS)and is exclusively limited to the *** most PCNSLs are diffuse large B-cell lymphomas,primary CNS T-cell lymphomas(PCNSTLs)are *** typically demonstrate some degree of enhancement on contrast-enhanced magnetic resonance imaging(MRI).To the best of our knowledge,non-enhancing PCNSTL has not been reported *** SUMMARY A 69-year-old male presented to the neurology department with complaints of mild cognitive impairment and gradual onset of left lower leg weakness over a span of two *** MRI showed asymmetric T2-hyperintense lesions within the *** enhancement was observed on the contrast-enhanced T1 *** initial diagnosis was neuro-Behçet’s *** high-dose steroid therapy,no alterations in the lesions were identified on initial *** patient’s symptoms deteriorated *** MRI performed one month after the initial scan revealed an increased lesion ***,brain biopsy confirmed the diagnosis of *** patient underwent definitive combined ***,the patient developed bacteremia and died of septic shock approximately three months after *** The absence of enhancement in the lesion did not rule out PCNSTL.A biopsy approach is advisable for pathological confirmation.

关键词： Central nervous system neoplasms Non-Hodgkin Lymphoma T-cell Lymphoma Primary central nervous system lymphoma Primary central nervous system T-cell lymphoma Case report

碳化硅量子点荧光特性及其致病镰刀菌活体细胞标记机制

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功能材料 2017年第5期48卷 5185-5189页

作者：柳洪洁孙丰飞宋月鹏朱彦敏康杰 kim hyoungseop 山东农业大学动物科技学院山东泰安271018 山东农业大学机械与电子工程学院山东泰安271018 韩国浦项工科大学韩国浦项790784

研究了腐蚀法制备的碳化硅量子点荧光特性及其致病镰刀菌活体细胞标记强度与机制。结果表明当激发光为340nm时SiC量子点光致发光强度最大,随着激发光波长增加,发射光波长出现红移现象,且具有较高的斯托克斯(Stokes)位移,由于荧光发射可... 详细信息

研究了腐蚀法制备的碳化硅量子点荧光特性及其致病镰刀菌活体细胞标记强度与机制。结果表明当激发光为340nm时SiC量子点光致发光强度最大,随着激发光波长增加,发射光波长出现红移现象,且具有较高的斯托克斯(Stokes)位移,由于荧光发射可以全色调谐,从而实现了致病镰刀菌的近紫外检测,可用来对自发荧光细胞的有效检测与定量分析。进一步对致病镰刀菌活体细胞SiC量子点荧光标记机制的研究结果表明,量子点通过网格蛋白依赖的内吞方式进入活体细胞内部,并均匀分布,从而实现了对致病镰刀菌的稳定荧光标记。另外基于实验结果与理论分析,提出了致病镰刀菌SiC量子点荧光标记模型。

关键词：碳化硅量子点致病镰刀菌活体细胞荧光特性与标记

Inhibiting scar formation via wearable multilayer stacked electret patch:Self-creation of persistent and customizable DC electric field for fibrogenic activity restriction

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InfoMat 2024年第3期6卷 66-80页

作者： Sung-Won kim Sumin Cho Donghan Lee Jiyu Hyun Sunmin Jang Inwoo Seo Hyun Su Park Hee Jae Hwang Hyung-seop Han Dae Hyeok Yang Heung Jae Chun Suk Ho Bhang Dongwhi Choi School of Chemical Engineering Sungkyunkwan UniversitySuwonRepublic of Korea Department of Mechanical Engineering(Integrated Engineering Program) Kyung Hee UniversityYonginGyeonggiRepublic of Korea Biomaterials Research Center Biomedical Research DivisionKorea Institute of Science and Technology(KIST)SeoulRepublic of Korea Department of Medical Life Sciences College of MedicineInstitute of Cell and Tissue EngineeringThe Catholic University of KoreaSeoulRepublic of Korea

Electrical stimulation has recently received attention as noninvasive treatment in skin wound healing with its outstanding biological property for clinical set***,the complexity of equipment for applying appropriate electrical stimulation remains an ongoing ***,we proposed a strategy for skin scar inhibition by providing electrical stimulation via a multilayer stacked electret(MS-electret),which can generate direct current(DC)electric field(EF)without any power supply *** addition,the MS-electret can easily control the intensity of EFs by simply stacking electret layers and maintain stable EF with the surface potential of 3400 V over 5 days owing to the injected charges on the electret *** confirmed inhibition of type 1 collagen andα-SMA expression of human dermal fibroblasts(hDFs)by 90%and 44%in vitro,indicating that the transition of hDFs to myofibroblasts was restricted by applying stable electrical *** further revealed a 20%significant decrease in the ratio of myofibroblasts caused by the MS-electret in *** findings present that the MS-electret is an outstanding candidate for effective skin scar inhibition with a battery-free,physiological electrical microenvironment,and noninvasive treatment that allows it to prevent external infection.

关键词： DC electric field dermal fibroblasts electret scar formation restriction self-creation of electrical stimulation

Fabrication of Fullerene-Reinforced Aluminum Matrix Nanocomposites

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Acta Metallurgica Sinica(English Letters) 2017年第10期30卷 973-982页

作者： Hamed Asgharzadeh Hamid Faraghi hyoung seop kim Department of Materials Engineering Faculty of Mechanical EngineeringUniversity of Tabriz Department of Materials Science and Engineering Pohang University of Science and Technology (POSTECH)

Fullerene-reinforced A1 matrix nanocomposites were fabricated by high-energy mechanical milling followed by consolidation through hot extrusion or high-pressure torsion（HPT）. The results indicate that a relatively homogeneous microstructure consisting of elongated, micrometer-sized A1 grains is formed in the hot-extruded specimens. However, the microstructure is not uniform along the radius of the HPT disks, which includes coarse grains near the center of the disk and ultrafine grains in the middle and along the edge of the specimen. Microstructural evaluations of the HPT disks indicate that A1 grain refinement occurs due to the addition of fullerene, as grain size is reduced to 60 nm from 118 nm. The formation of the harmful aluminum carbide phase is not detected during the fabrication of Al/C（60） nanocomposites. The hardness, yield stress, and ultimate tensile strength of the Al-2 vol.% C（60） nanocomposites are about 27-160% higher than those of the monolithic A1 samples, revealing the effective strengthening of fullerene particles in A1 matrix. Moreover,mechanical properties of the Al/fullerene nanocomposites are significantly enhanced（59-272%） by utilizing HPT in comparison to hot-extruded specimens due to their much finer A1 grain structure. The reduction in the number and the size of the dimples, as well as the formation of smooth regions on the tensile fracture surface of Al/C（60）, results in their overall lower ductility compared to monolithic Al.

关键词： Aluminum Fullerene High-pressure torsion Hot extrusion Microstructure Mechanical properties