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Journal of Materials Science & Technology 2022年第3期98卷 248-257页

作者： Dong Hwi kim Jee-Hyun Kang Hojun Gwon Joo Hyun Ryu sung-joon kim Graduate Institute for Ferrous Technology Pohang University of Science and TechnologyPohang 37673Republic of Korea School of Materials Science and Engineering Institute of Materials TechnologyYeungnam UniversityGyeongsan 38541Republic of Korea POSCO Technical Research Laboratories POSCOGwangyang 57807Republic of Korea

Silicon is an essential alloying element in quenching and partitioning(Q&P)steels,because it is known to suppress carbide precipitation during partitioning step and promote carbon partitioning to stabilize *** 2 wt%Si was added to 10Mn-2Al-0.2C steel,the size and fraction of the carbides formed during partitioning became smaller than in the Si-free ***,the suppression of carbide formation promoted C partitioning into austenite as ***,austenite stability was always lower with Si under the equivalent partitioning condition because Si effectively decreased the stacking fault energy of *** partitioning progressed,the both yield and tensile strengths of the Si-added steel exceeded that of the Si-free steel with the similar ductility *** was because Si was an effective solid solution strengthener,and the austenite in the Si-added steel exhibited the appropriate stability to gradually transform into martensite throughout the *** resulting strengthening effect compensated for the softening caused by martensite ***,strain hardening rate decreased continuously throughout deformation,which resulted in high tensile strength and ductility.

关键词： Steels Q&P steel Silicon Austenite stability Tensile deformation Stacking fault energy Medium Mn steel

Microstructure and mechanical behavior of cold-rolled CMnAlSi TRIP-aided steel sheets

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中国有色金属学会会刊：英文版 2009年第S3期19卷 579-582页

作者：景财年王明刚王作成谭启忠 sung-joon kim School of Materials Science and Engineering Shandong Jianzhu University School of Materials Science and Engineering Shandong University Korea Institute of Machinery and Materials

The microstructure, mechanical properties and retained austenite stability of CMnAlSi-TRIP steels were investigated. Optical microscopy and X-ray diffractometry were used to analyze the microstructure, volume fraction and carbon concentration of retained austenite, while the tensile tests were performed to study the retained austenite stability against strain-induced martensitic transformation. The results show that the mechanical properties of the CMnAlSi cold-rolled TRIP-aided steels fabricated by proper heat treatment display good combination of strength and ductility after isothermal bainitic transformation (IBT) treatment at 420-450 ℃ for 60-120 s. The austenite transformation kinetics is influenced significantly by the IBT temperature, and the high mechanical stability of retained austenite, governed by its carbon concentration, and determines high strain hardening during deformation.

关键词： transformation induced plasticity(TRIP) isothermal bainitic transformation (IBT) mechanical properties retained austenite stability

Influence of glass-based dental ceramic type and thickness with identical shade on the light transmittance and the degree of conversion of resin cement

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International Journal of Oral Science 2018年第1期10卷 44-49页

作者： Soram Oh Su-Mi Shin Hyun-Jung kim Janghyun Paek sung-joon kim Tai Hyun Yoon Sun-Young kim Department of Conservative Dentistry Graduate School Kyung Hee University Seoul Korea Department of Prosthodontics School of Dentistry Kyung Hee University Seoul Korea Department of Dentistry School of Medicine Jeju National University Jeju Korea Department of Physics Korea University Seoul Korea and SDepartment of Conservative Dentistry Dental Research Institute School of Dentistry Seoul National University Seoul Korea

The purpose of this study was to assess the influence of the types and thicknesses of glass ceramic plates on light transmittance and compare the degrees of conversion(DC) of resin cement under the ceramic materials. Three ceramic plates with thicknesses of 0.5, 1.0, 2.0, and 4.0 mm were fabricated from each of five commercial ceramic blocks in shade A2: high-translucency and low-translucency IPS Empress CAD(EmpHT and EmpLT); high-translucency and low-translucency IPS *** CAD(EmxHT and EmxLT); and Vita Mark Ⅱ(Vita). The translucency parameter was obtained using a colorimeter. The light transmittance rate was measured using a photodetector attached to an optical power meter. The DC of a resin cement(Variolink N) underneath the ceramic plates was examined by Fourier transform infrared spectroscopy. The translucency parameter, light transmittance rate, and DC showed significant differences by ceramic type and thickness(P 0.05). Both type and thickness of the glass ceramics significantly influenced the light transmittance and DC of the light-cured resin cement beneath the ceramic of the same shade.

关键词：中国牙科口腔医学

Grasper type scissors for endoscopic submucosal dissection of gastric epithelial neoplasia

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World Journal of Gastroenterology 2013年第37期19卷 6221-6227页

作者： Woo-Chul Chung Byung-Wook kim Chul-Hyun Lim Tae-Ho kim Jae-Myung Park joon-sung kim Division of Gastroenterology Department of Internal MedicineSuwon St.Vincent’s HospitalThe Catholic University of Korea Division of Gastroenterology Department of Internal MedicineIncheon St.Mary’s HospitalThe Catholic University of Korea Division of Gastroenterology Department of Internal MedicineSeoul St.Mary’s HospitalThe Catholic University of Korea Division of Gastroenterology Department of Internal MedicineBucheon St.Mary’s HospitalThe Catholic University of Korea

AIM:To evaluate the efficacy and safety of grasper type scissors(GTS)for endoscopic submucosal dissection(ESD)of gastric epithelial ***:The study was performed by 4 endoscopists in 4 institutions affiliated to The Catholic University of *** was performed in 76 consecutive patients with gastric epithelial neoplasia by using the GTS(37 patients)or the hook knife plus coagrasper(HKC)(39 patients).The complete resection rate,complication rate,total time elapsed and elapsed time per square centimeter of the dissected specimen were analyzed between the GTS and HKC ***:The mean age of the GTS group was 62.3±11.4 years and mean age of the HKC group was 65.6±10.1 *** adenocarcinoma was found in32.4%in the GTS group and 33.3%in the HKC *** procedures were performed without interruption in every case in both *** en bloc resection rates of both groups were 100%.The total time elapsed during the procedure was 44.54±21.72 min in the GTS group and 43.77±21.84 min in the HKC group(P=0.88)and the time elapsed per square centimeter of the resected lesion was 7.53±6.35 min/cm2in the GTS group and 6.92±5.93 min/cm2in the HKC group(P=0.66).The overall complication rate was not significantly different between the two ***:GTS is a safe and effective device for ESD compared with *** can be performed with GTS alone,which can reduce the costs for ESD.

关键词： Gastric epithelial neoplasia Endoscopic submucosal dissection Grasper type scissors Hook knife Coagrasper

On the Crystal Structure of Cr2N Precipitates in High-Nitrogen Austenitic Stainless Steels

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On the Crystal Structure of Cr2N Precipitates in High-Nitrog...

Aligned Ion Conduction Pathway of Polyrotaxane‑Based Electrolyte with Dispersed Hydrophobic Chains for Solid‑State Lithium–Oxygen Batteries

第二届先进钢铁结构材料国际会议

作者： Tae-HoLee Chang Gil Lee sung-joon kim Setsuo Takaki Materials Processing Department Korea Institute of Machinery and Materials 66 Sangnam Changwon 641-010Chang—Seok Oh Faculty of Engineering Kyushu University 6-10-1 Hakozaki Higashi-ku Fukuoka 812-8581 Japan

The crystal structure of CrN precipitates in high-nitrogen austenitic steel was investigated using transmission electron microscopy (TEM). Based on the analyses of SAD patterns, the crystal structure of CrN was confirmed to be trigonal structure (P31m) characterized by three sets of superlattice reflections (1/3 1/3 0), (001) and (1/3 1/3 1), and could be explained in terms of ε-type occupational ordering of nitrogen.

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Nano-Micro Letters 2025年第2期17卷 169-186页

作者： Bitgaram kim Myeong‑Chang sung Gwang‑Hee Lee Byoungjoon Hwang Sojung Seo Ji‑Hun Seo Dong‑Wan kim Department of Materials Science and Engineering Korea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea School of Civil Environmental and Architectural EngineeringKorea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea Materials Science and Chemical Engineering Center Institute for Advanced Engineering(IAE)Yongin 17180Republic of Korea

A critical challenge hindering the practical application of lithium–oxygen batteries(LOBs)is the inevitable problems associated with liquid electrolytes,such as evaporation and safety *** study addresses these problems by proposing a modified polyrotaxane(mPR)-based solid polymer electrolyte(SPE)design that simultaneously mitigates solvent-related problems and improves ***-SPE exhibits high ion conductivity(2.8×10^(−3)S cm^(−1)at 25℃)through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain *** this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 *** situ Raman spectroscopy reveals the presence of an LiO_(2)intermediate alongside Li_(2)O_(2)during oxygen *** situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture,as demonstrated by the air permeability *** present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.

关键词： Solid polymer electrolyte Lithium-oxygen batteries Polyrotaxane ion conductivity Hydrophobic chain

Regulation of sleep by astrocytes in the hypothalamic ventrolateral preoptic nucleus

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Neural Regeneration Research 2025年第4期20卷 1098-1100页

作者： Jae-Hong kim Ruqayya Afridi Il-sung Jang Maan Gee Lee Kyoungho Suk Brain Korea 21 four KNU Convergence Educational Program of Biomedical Sciences for Creative Future Talents School of MedicineKyungpook National UniversityDaeguRepublic of Korea Department of Pharmacology School of MedicineKyungpook National UniversityDaeguRepublic of Korea Department of Pharmacology School of DentistryKyungpook National UniversityDaeguRepublic of Korea Brain Science&Engineering Institute Kyungpook National UniversityDaeguRepublic of Korea

Astrocytes are functionally dynamic cells that support neurons in multiple ways throughout an organism’s *** astrocytic regulation of neuronal activity has been increasingly recognized in recent *** are now recognized as playing a more complex role than mere bystanders in the central nervous ***,their role in regulating the sleep neurocircuitry is not well *** this perspective,we highlight the role of astrocytes in sleep modulation,with a particular focus on regulatory mechanisms related to the ventrolateral preoptic nucleus(VLPO)of the *** briefly discuss recent literature reporting the role of VLPO astrocytes in regulating sleep-associated behaviors.

关键词： sleep ventrolateral astrocytes

Effect of BainiticTreatment on Microstructure and Mechanical Properties of TRIP Cold-Rolled Steel Sheets

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Journal of Iron and Steel Research International 2011年第S1期18卷 1004-1007页

作者： kim sung-joon Korea Institute of Machinery Science Changwon 641010Korea

The effects of bainitic treatment on microstructure and mechanical properties of 0.10C-1.5Mn-l.5Al TRIP-aided cold-rolled steels have been *** samples were heated by intercritical annealing at 820℃for 2 min and quenched in banitic temperature with different hoding time for 5 to 300s,two salt bath were used for the heat *** results show that the yield strength and elongation increase with the increasing of bainitic holding time,while the tensile strength *** volume fraction of retained austenite rise at the beginning of bainitic holding and then reduce,the carbon content of retained austenite increase during the bainitic *** tensile strengthen multiply elongation reaches the highest value at *** mechanical stability of retained austenite fits well with strain hardening during deformation.

关键词： TRIP bainitic treatment microstructure mechanical properties retained austenite

Uncertainty analysis of flow rate measurement for multiphase flow using CFD

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Acta Mechanica Sinica 2015年第5期31卷 698-707页

作者： joon-Hyung kim Uk-Hee Jung sung kim joon-Yong Yoon Young-Seok Choi Department of Mechanical Design Engineering Hanyang University Thermal & Fluid System R&BD Group Korea Institute of Industrial Technology Energy System Engineering University of Science and Technology

The venturi meter has an advantage in its use,because it can measure flow without being much affected by the type of the measured fluid or flow ***,it has excellent versatility and is being widely applied in many *** flow of a liquid containing air is a representative example of a multiphase flow and exhibits complex flow *** particular,the greater the gas volume fraction（GVF）,the more inhomogeneous the flow *** a result,using a venturi meter to measure the rate of a flow that has a high GVF generates an *** this study,the cause of the error occurred in measuring the flow rate for the multiphase flow when using the venturi meter for analysis by *** ensure the reliability of this study,the accuracy of the multiphase flow models for numerical analysis was verified through comparison between the calculated results of numerical analysis and the experimental *** a result,the Grace model,which is a multiphase flow model established by an experiment with water and air,was confirmed to have the highest ***,the characteristics of the internal flow Held about the multiphase flow analysis result generated by applying the Grace model were analyzed to find the cause of the uncertainty occurring when measuring the flow rate of the multiphase flow using the venturi meter.A phase separation phenomenon occurred due to a density difference of water and air inside the venturi,and flow inhomogeneity happened according to the flow velocity difference of each *** was confirmed that this flow inhomogeneity increased as the GVF increased due to the uncertainty of the flow measurement.

关键词： Multiphase flow Measurement Numerical analysis Venturi meter Gas volume fraction(GVF) Uncertainty Multiphase flow model Grace model

DYNAMIC PROPERTIES OF AL-ALLOY FOAM BEAM DAMAGED BY COMPRESSIVE FATIGUE

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Acta Mechanica Solida Sinica 2008年第3期21卷 241-246页

作者： sung-Gaun kim Ilhyun kim Amkee kim Seung-joon kim Junhong Park Division of Mechanical and Automotive Engineering Kongju National University 275 Budae-dongCheonan Chungnam 330-717 Korea Department of Mechanical Engineering Hanyang University Seongdong-Gu Seoul 133-791 Korea

The permanent residual strain in aluminum （Al） alloy foams induced by compressive fatigue gradually increases with the increasing number of loading cycles. Consequently, the progressive shortening of Al-alloy foam degrades the dynamic material performance by the failure and ratcheting of multi-cells in the foam. In this paper, the dynamic properties of Al-alloy foams damaged by compressive fatigue were studied. The beam specimens with various residual strains were made by cyclic compression-compression stress. The dynamic bending modulus and loss factor were evaluated by using a beam transfer function method. As a result, the dynamic bending stiffness of Al-alloy foam turned out to be decreased due to damage while the loss factor was improved because of the increasing energy dissipation of such factors as cracked cell walls formed during the shortening process of the foam. The loss factor shows a manifest dependence on the fatigue residual strain.

关键词： Aluminum foam fatigue dynamic stiffness loss factor