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Experiments and computer simulation analysis of impact behaviors of micro-sized abrasive in waterjet cutting of thin multiple layered materials

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中国有色金属学会会刊：英文版 2012年第S3期22卷 864-869页

作者： Jung-Han LEE kang-Su PARK Myung Chang kang Bo Sik kang Bo sung SHIN Engineering Research Center Pusan National University National Core Research Center Pusan National University Mechanical System Safety Research Division Korea Institute of Machinery and Materials

The abrasive waterjet (AWJ) is now widely used in the advanced cutting processes of polymers,metals,glass,ceramics and composite materials like thin multiple-layered material (TMM).Various research and development efforts have recently been made to understand the science of ***,the interaction mechanism between a workpiece and high-velocity abrasive particles still remains a complicated *** this work,the material removal mechanisms of AWJ such as micro penetration and micro dent were experimentally *** addition,a new computer simulation model considering high strain rate effect was proposed to understand the micro impact behavior of high-velocity micro-sized abrasives in AWJ cutting.

关键词： abrasive waterjet thin multiple layered materials micro-sized abrasive micro penetration micro dent

Pressure-responsive pH-triggered layer-by-layer coating of paclitaxel-eluting balloon catheters for instant high-dose drug delivery for percutaneous coronary artery intervention

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Nano Research 2024年第10期17卷 9141-9151页

作者： Jeong Yu Lee Shonit Nair Sharma sung-Yu Hong Young-Guk Ko Yangsoo Jang Minjae Do Michael Christopher Stark Qiwen Peng Benjamin Allen Mossburg Bo Chan Seo Yuhan Lee Department of Materials Science and Engineering Korea Advanced Institute of Science and TechnologyDaejeon 305-701Republic of Korea Department of Anesthesiology Perioperativeand Pain MedicineCenter for Accelerated Medical Innovation&Center for NanomedicineBrigham and Women’s HospitalHarvard Medical SchoolBostonMA 02115USA Department of Biological Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA Cardiovascular Product Evaluation Center Yonsei University College of MedicineSeoul 120-752Republic of Korea Division of Cardiology Department of Internal MedicineSeverance Cardiovascular HospitalYonsei University College of MedicineSeoul 120-752Republic of Korea

Cardiovascular diseases remain the leading cause of mortality worldwide,with percutaneous coronary interventions(PCI)using drug-eluting stents(DES)as the standard treatment for coronary artery *** advancements in DES technology,challenges such as restenosis and stent thrombosis still necessitate further interventions and carry considerable risks,highlighting an urgent need for a novel therapeutic approach with lower restenosis rates and reduced reintervention *** balloons(DEBs)coated with anti-proliferative agents offer a novel method of local drug delivery for reducing restenosis by directly administering drugs to the lesion ***,efficient delivery of drugs within the brief procedural window while minimizing drug loss during maneuvering to the target site remains a ***,we developed a pressure-responsive and pH-triggered,paclitaxel(PTX)coated DEB catheter for rapid and high-dose delivery of paclitaxel to the lesion sites,overcoming the limitations of drug dispersion and inefficiencies associated with conventional *** the charge reversion of albumin around its isoelectric point,paclitaxel-loaded human serum albumin nanoparticles(PTX-HSA-NPs)and heparin were coated using a layer-by-layer deposition method at pH *** exposure to physiological pH(i.e.,7.4),the coating is rapidly released from the balloon *** with a protective shellac coating,the DEB achieved controlled release of high-dose paclitaxel to the arterial tissue in vivo(up to 400μg per gram tissue),exceeding current DEBs in the *** results suggest the pH-responsive,multi-layer coated DEB’s potential for superior procedural outcomes,addressing a critical unmet need in PCI.

关键词： drug-eluting balloon layer-by-layer coating coronary artery disease paclitaxel

Exploration of cobalt selenite-carbon composite porous nanofibers as anode for sodium-ion batteries and unveiling their conversion reaction mechanism

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Journal of Materials Science & Technology 2021年第30期89卷 24-35页

作者： Jin-sung Park Gi Dae Park Yun Chan kang Department of Materials Science and Engineering Korea UniversityAnam-DongSeongbuk-GuSeoul136-713Republic of Korea

Efforts have been made to develop a promising anode material with a novel composition for sodiumion batteries(SIBs).In this study,the sodium-ion storage mechanism of transition metal selenite that comprises transition metal cation coupled with two anions is *** cobalt selenite(CoSeO_(3))-carbon composite nanofibers containing numerous pores are synthesized via electrospinning *** heat treatment of the electrospun nanofibers containing selenium,CoSe_(2)nanoclusters are *** the subsequent oxidation,CoSe_(2)transformed into amorphous CoSeO_(3)and some part of carbon was oxidized into CO_(2),leaving the pores inside the *** unveil the electrochemical reaction mechanism,analytical methods including cyclic voltammetry,ex-situ X-ray photoelectron spectroscopy,ex-situ transmission electron microscopy,and in-situ electrochemical impedance spectroscopy techniques were *** on the analyses,the following conversion reaction from the second cycle onward is suggested:CoO+xSeO_(2)+(1-x)Se+4(x+1)Na^(+)+4(x+1)e~-?Co+(2x+1)Na_(2)O+Na_(2)***,the electrochemical properties of porous CoSeO_(3)-carbon composite nanofibers are analyzed in *** anode material exhibited stable cycle stability up to 200 cycles at 0.5 A g^(-1)and high rate performance up to 5 A g^(-1).

关键词： Anode materials Sodium-ion batteries Conversion reaction Metal selenite Electrospinning

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

Follow-up strategy for early detection of delayed pseudoaneurysms in patients with blunt traumatic spleen injury: A single-center retrospective study

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World Journal of Gastrointestinal Surgery 2024年第10期16卷 3163-3170页

作者： sung Hoon Cho Gun Woo Kim Suyeong Hwang Kyoung Hoon Lim Department of Surgery Trauma CenterKyungpook National University HospitalSchool of MedicineKyungpook National UniversityDaegu 41944South Korea

BACKGROUND The spleen is the most commonly injured solid organ in blunt abdominal trauma,and splenic pseudoaneurysm rupture is associated with a high risk of *** management has become the standard treatment for hemodynam-ically stable patients with splenic *** the other hand,delayed splenic pseudoaneurysms can develop in any patient,and at present,there are no known risk factors that may reliably predict their ***,there is a lack of consensus regarding the most appropriate strategies for monitoring and mana-ging splenic injuries,especially lower-grade(I-III).AIM To determine the predictors of pseudo-aneurysm formation following splenic injury and develop follow-up strategies for early detection of *** We retrospectively analyzed patients who visited the Level I Trauma Center bet-ween January 2013 and December 2022 and were diagnosed with spleen injuries after blunt abdominal *** Using the American Association for the Surgery of Trauma spleen injury scale,the splenic injuries were categorized into the following order based on severity:Grade I(n=57,17.6%),grade II(n=114,35.3%),grade III(n=89,27.6%),grade IV(n=50,15.5%),and grade V(n=13,4.0%).Of a total of 323 patients,35 underwent splenectomy and 126 underwent angioembolization.19 underwent delayed angioembolization,and 5 under-went both initial and delayed *** 14 patients who had undergone delayed angioembolization,no extravasation or pseudoaneurysm was observed on the initial computed tomography *** are no particular patient-related risk factors for the formation of a delayed splenic pseudoaneurysm,which can occur even in a grade I spleen injury or even 21 days after the *** mean detection time for a delayed pseudoaneurysm was 6.26±5.4(1-21,median:6,inter-quartile range:2-9)*** We recommend regular follow-up computed tomography scans,including an arterial and portal venous phase,at least 1 week an

关键词： Blunt trauma Spleen injury Delayed pseudoaneurysm Angioembolization Nonoperative management

Addition of cerium and yttrium to ferritic steel weld metal to improve hydrogen trapping efficiency

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International Journal of Minerals,Metallurgy and Materials 2017年第4期24卷 415-422页

作者： sung Jin Kim kang Mook Ryu Min-suk Oh Department of Advanced Materials Engineering Sunchon National University Jungang-ro Suncheon 540-742 Republic of Korea POSCO Steel Solution Marketing Division Geidong-Dong Pohang 790-704 Republic of Korea Automotive Components & Materials R&D Group Korea Institute of Industrial Technology 6 Cheomdan-gwagiro 208 beon-gil Gwangju 61012 Republic of Korea

The applicability of Ce and Y as promising candidate elements to form irreversible traps in weld metal was investigated by thermal desorption spectroscopy(TDS) with gas chromatography(GC). The precise nature of the precipitate particles newly formed in the weld metal by the addition of Ce and Y to a certain alloy system was characterized. Moreover,the hydrogen trapping efficiency expressed as the reduction of the diffusible hydrogen in the weld metal was analyzed. The results showed that the addition of Ce and/or Y to this alloy system led to the formation of a mixed type of(Ce,Ti)-based oxide,(Y,Ni)-based carbide,or(Ce,Y,Ti)-based oxide particles. Because of the high activation energy of the mixed type of particles(≥ 150 k J/mol),the trapping efficiency for hydrogen was considered to be sufficiently high to effectively reduce the diffusible hydrogen content.

关键词： hydrogen trapping weld rare earth metals cerium yttrium activation energy

Degradable and Tunable Keratin-fibrinogen Hydrogel as Controlled Release System for Skin Tissue Regeneration

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Journal of Bionic Engineering 2023年第3期20卷 1049-1059页

作者： sung Jun Min Jae Seo Lee Haram Nah Ho-Jin moon Sang Jin Lee Hyeon Jeong kang Yu-Shik Hwang Il Keun Kwon Dong Nyoung Heo Department of Dentistry Graduate SchoolKyung Hee University26 Kyungheedae-RoDongdaemun-GuSeoul02447Republic of Korea Biofriends Inc 26 Kyungheedae-RoDongdaemun-GuSeoul02447Republic of Korea Department of Dental Materials School of DentistryKyung Hee University26 Kyungheedae-RoDongdaemun-GuSeoul02447Republic of Korea Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology School of DentistryKyung Hee UniversitySeoul02447Korea Kyung Hee University Medical Science Research Institute Kyung Hee University23 Kyungheedae-RoDongdaemun-GuSeoul02447Republic of Korea

Biodegradable hydrogels are promising biomaterials for use in controlled-release systems for skin tissue regeneration. Controlled delivery systems constitute an important aspect of tissue engineering because they can modulate various physiological responses, including early immune response, tissue remodeling, and cell proliferation and maturation in the wound-healing process. Hydrogels composed of various biomaterials have been developed to overcome the limitations of conventional drug- or protein-delivery systems, such as limited targeting ability, low stability, and the induction of drug resistance. Hydrogels based on keratin, a natural polymer extracted from human hair, can provide adequate cell support and control homeostasis. Consequently, they can be applied for skin tissue engineering. In this study, we prepared degradable, tunable, and biocompatible hydrogels for controllable protein delivery. We synthesized keratin-fibrinogen (KER-FBG) by the chemical coupling reaction and prepared hydrogels through polymerization with thrombin. The structures and morphologies of the KER-FBG hydrogels were confirmed. Furthermore, the mechanical properties, swelling ratio, degradation, release behavior, and biocompatibility were investigated. The KER-FBG hydrogels presented promising biological performance, indicating that the material is suitable as a controlled protein delivery carrier.

关键词： Keratin Fibrinogen Hydrogel Drug delivery Degradable

Influence of tool plunge depth and welding distance on friction stir lap welding of AA5454-O aluminum alloy plates with different thicknesses

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中国有色金属学会会刊：英文版 2012年第S3期22卷 624-628页

作者： Jun-Won KWON Myoung-Soo kang sung-Ook YOON Yong-Jai KWON sung-Tae HONG Dae-Il KIM Kwang-Hak LEE Jong-Dock SEO Jin-Soo moon Kyung-Sik HAN School of Materials Science and Engineering University of Ulsan School of Mechanical Engineering University of Ulsan Technical Research Laboratories Shin Young Co.Ltd. Automotive Parts Innovation Center Ulsan Technopark

AA5454-O aluminum alloy plates with thicknesses of 1.4 and 1.0 mm were friction-stir-lap-welded (FSLWed).The influences of the tool plunge depth and welding distance on surface appearance,macrostructure and mechanical properties of the FSLWed plates were experimentally *** tensile shear load of the FSLWed plates was compared with that of the adhesive-bonded ***-free FSLWed zones were successfully obtained in all the tool plunge depths and the welding *** FSLWed zones exhibited the relatively smooth surface *** all the FSLWed conditions,the FSLWed zone exhibited higher average hardness than the base *** addition,the upper plate exhibited a higher average hardness than the lower plate,although there was no special tendency in spite of the change in the tool plunge depth and the welding *** maximum tensile shear load of the FSLWed plates was much higher than that of the adhesive-bonded aluminum alloy ***,under the FSLW condition of the plunge depth of 1.8 mm and the welding distance of 40 mm,the tensile shear load of the FSLWed plate reached a level about 41% greater than that of the adhesive-bonded aluminum alloy *** addition,the maximum tensile shear load of the FSLWed plate was increased with the increase of the welding distance.

关键词： friction stir lap welding AA5450-O aluminum alloy tool plunge depth welding distance mechanical properties

Porous FeS nanofibers with numerous nanovoids obtained by Kirkendall diffusion effect for use as anode materials for sodium-ion batteries

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Nano Research 2017年第3期10卷 897-907页

作者： Jung Sang Cho Jin-sung Park Yun Chan kang Department of Materials Science and Engineering Korea University Anam-Dong Seongbuk-Gu Seou1136-713 Republic of Korea Department of Engineering Chemistry Chungbuk National University Chungbuk 361-763 Republic of Korea

Porous FeS nanofibers with numerous nanovoids for use as anode materials for sodium-ion batteries were prepared by electrospinning and subsequent sulfidation. The post-treatment of the as-spun Fe（acac）3-polyacrylonitrile composite nanofibers in an air atmosphere yielded hollow Fe2O3 nanofibers due to Ostwald ripening. The ultrafine Fe2O3 nanocrystals formed at the center of the fiber diffused toward the outside of the fiber via Ostwald ripening. On sulfidation, the Fe2O3 hollow nanofibers were transformed into porous FeS nanofibers, which contained numerous nanovoids. The formation of porosity in the FeS nanofibers was driven by nanoscale Kirkendall diffusion. The porous FeS nanofibers were very structurally stable and had superior sodium-ion storage properties compared with the hollow Fe2O3 nanofibers. The discharge capacities of the porous FeS nanofibers for the Ist and 150th cycles at a current density of 500 mA.g-1 were 561 and 592 mA.h-g-1, respectively. The FeS nanofibers had final discharge capacities of 456, 437, 413, 394, 380, and 353 mA-h.g-1 at current densities of 0.2, 0.5, 1.0, 2.0, 3.0, and 5.0 A.g-1, respectively.

关键词： iron sulfide sodium-ion batteries Kirkendall effect nanofibers electrospinning