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中国有色金属学会会刊：英文版 2009年第B09期19卷 301-306页

作者： tae-soo kwak Yong-Chul LEE Gyung-Nyun KIM Dae-Bong CHOI Mikio YAMANOI Hitoshi OHMORI Department of Mechanical Engineering Jinju National University

This study is focused on the application of an effective fabrication method combining electrolytic in-process dressing(ELID) grinding and magnetic assisted polishing(MAP) to nano-precision mirror surface grinding on the optics glass-ceramic named Zerodure that is commonly used in precision optics components. The results show the variation of surface roughness after MAP processes utilizing Fe+CeO2, Fe+CeO2+diamond paste and Fe+diamond paste are applied to ELID ground surfaces. The MAP surface roughnesses for ELID ground surface roughnesses(Ra) of 52.1, 39.8 and 51.1 nm using #1200 grinding wheel are improved to 6.1, 4.6 and 1.9 nm, respectively. The surface roughness of MAP process using Fe+CeO2+diamond paste is superior to that using other processes. Moreover, it takes less than 10 min to conduct the MAP processes. The combined method suggested effectively reduces the working time to get the required surface qualities.

关键词：在线电解修整光学玻璃纳米相抛光材料电解过程表面粗糙度地面粗糙度磨削

Microstructure and Mechanical Properties of TiB-Containing Al–Zn Binary Alloys

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Journal of Materials Science & Technology 2016年第7期32卷 653-659页

作者： Sang-soo Shin Gil-Yong Yeom tae-Yang kwak Ik-Min Park Department of Materials Science and Engineering Pusan National University Busan 609-735 Republic of Korea Liquid Processing & Casting Technology R&BD Group Korea Institute of Industrial Technology Incheon 21999 Republic of Korea

The microstructure and mechanical properties of newly developed Al-35Zn cast alloys with TiB refiner addition were evaluated by X-ray diffractometry, optical microscopy, and scanning electron microscopy coupled with energy dispersive spectrometry. The microstructure of these alloys featured α-Al den- drites surrounded by AI-Zn （α ＋ rI） eutectic structures. After the addition of TiB refiner, the alloy grain sizes decreased, and its morphology abruptly changed from dendritic to equiaxed grains. Such an im- proved microstructure of the modified alloys was accompanied by a significant increase in the tensile strength and elongation percentage compared to those of the AI-Zn or Zn-Al-based alloys. The results showed that with the increase of TiB content up to 0.05%, the morphology of α-Al dendrites and α ＋ T1 phases changed from coarse dendrite and lamellar structures into independent and fine ones. Based on these results, the effect of TiB refiner addition on the microstructure and mechanical properties of the AI-35Zn binary alloys was investigated.

关键词： Al-Zn(-Cu) alloyEutectic structureHigh strengthTiB2

Critical cooling rate on carbide precipitation during quenching of austenitic manganese steel

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China Foundry 2010年第2期7卷 178-182页

作者： Youn-soo Ham Jeong-tae Kim Si-Young kwak Jeong-Kil Choi Woo-Young Yoon Daeyang R-Tech.Co. Ltd290-28Daehwa-DongDaeduk-GuDaejeonKorea e-Design Center KITECH7-47Songdo-DongYeonsu-GuIncheon 406-800Korea Department of Materials Science and Engineering Korea UniversityAnam-DongSeongbuk-GuSeoul 136-701Korea

Critical cooling rate to avoid carbide precipitation during quenching of austenitic manganese steel was investigated by means of optical microscopy,image analyzer and numerical *** efficient heat treatment analysis program including temperature-dependent material properties was developed for the prediction of cooling rate and probability of carbide precipitation during quenching by finite difference ***-dependent heat transfer coefficient was adopted to achieve more precise *** ratio of carbide precipitation was measured by image analyzer to determine the critical point of carbide ***-dependent critical cooling rate at that point was calculated by the developed numerical ***,the probability of carbide precipitation on the whole area of specimen can be predicted by the proposed numerical program and the numerical result of a specimen was compared with the experimental result.

关键词： austenitic manganese steel carbide precipitation quenching critical cooling rate

Velocity Profiles between Two Baffles in a Shell and Tube Heat Exchanger

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Journal of Thermal Science 2015年第4期24卷 356-363页

作者： tae-Hyun Chang Chang-Hoan Lee Hae-soo Lee Kwon-soo Lee Senior Research Fellow of RESEAT Korea Institute of Science and Technology Information Korea Institute of Science and Technology Information Postdoctoral Research Fellow School of Mechanical Engineering of Kyungnam University International University of Korea

Heat exchangers are extensively utilized for waste heat recovery,oil refining,chemical processing,and steam *** this study,velocity profiles are measured using a 3D particle image velocimetry(PIV)system between two baffles in a shell and tube heat exchanger for parallel and counter *** PIV and computational fluid dynamics results show the occurrence of some strong vectors near the *** vectors are assumed due to the clearance between the inner tubes and the front ***,the major parts of the vectors are moved out through the bottom opening of the rear baffle,and other vectors produce a large circle between the two *** simulations are conducted to investigate the effects of the baffle on the heat exchanger using the Fluent *** k-εturbulence model is employed to calculate the flows along the heat exchanger.

关键词： Baffle P1V Shell and tube heat exchanger Cut off ratio CFD

Generation of mesenchymal stem-like cells for producing extracellular vesicles

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World Journal of Stem Cells 2019年第5期11卷 270-280页

作者： soo Kim tae Min Kim Brexogen Research Center Brexogen Inc. Seoul Songpa-gu 05718 South Korea Graduate School of International Agricultural Technology and Institute of Green- Bio Science and Technology Seoul National University Gangwon-do Pyeongchang 25354 South Korea

Mesenchymal stem cells (MSCs) are multipotent progenitor cells with therapeutic potential against autoimmune diseases, inflammation, ischemia, and metabolic disorders. Contrary to the previous conceptions, recent studies have revealed that the tissue repair and immunomodulatory functions of MSCs are largely attributed to their secretome, rather than their potential to differentiate into desired cell types. The composition of MSC secretome encompasses cytokines and growth factors, in addition to the cell-derived structures known as extracellular vesicles (EVs). EVs are membrane-enclosed nanoparticles that are capable of delivering biomolecules, and it is now believed that MSC-derived EVs are the major players that induce biological changes in the target tissues. Based on these EVs’ characteristics, the potential of EVs derived from MSC (MSC-EV) in terms of tissue regeneration and immune modulation has grown during the last decade. However, the use of MSCs for producing sufficient amount of EVs has not been satisfactory due to limitations in the cell growth and large variations among the donor cell types. In this regard, pluripotent stem cells (PSCs)-derived MSC-like cells, which can be robustly induced and expanded in vitro, have emerged as more accessible cell source that can overcome current limitations of using MSCs for EV production. In this review, we have highlighted the methods of generating MSC-like cells from PSCs and their therapeutic outcome in preclinical studies. Finally, we have also discussed future requirements for making this cell-free therapy clinically feasible.

关键词： Mesenchymal stem cells Extracellular vesicles Preclinical studies Exosomes

Pancreatic parenchymal injection of ethanol and octreotide to induce focal pancreatic fibrosis in rats: Strategies to eliminate postoperative pancreatic fistula

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Hepatobiliary & Pancreatic Diseases International 2018年第1期17卷 81-85页

作者： soo Ho Lee tae Ho Hong Department of Surgery Uijeongbu St.Mary’s Hospital College of Medicine The Catholic University of Korea Department of Surgery Seoul St.Mary’s Hospital College of Medicine The Catholic University of Korea

Background: Postoperative pancreatic fistula(POPF) is more likely to occur in a soft pancreas compared to a hard pancreas in which fibrosis has progressed. There is almost no leakage at the anastomosis site or cut surface of a hard pancreas. The aim of this study was to induce localized fibrosis at the cut surface of the pancreas in a rat ***: Thirty-six rats were divided into three groups(group S: normal saline group; group E: ethanol group; and group O: octreotide group). Each rat was directly injected with a particular compound at the duodenal lobe of the pancreatic parenchyma. Each group was divided into three subgroups according to the time of post-injection sacrifice(1, 2, or 4 weeks). The hardness, suture holding capacity(SHC), and histological fibrosis grade of each pancreas were ***: The hardness, SHC, and fibrosis grade of groups E and O were increased at week 1, with greater increases in group E(all P < 0.001). In a subgroup comparison, the hardness, SHC, and fibrosis grade of group E tended to decrease gradually over time, with no regular pattern evident in group O. A comparison between the injected site(duodenal lobe) and non-injected site(splenic lobe) of the pancreas revealed increases in the three parameters of group E only in the duodenal lobe, with increases in group O at both the duodenal and splenic ***: Parenchymal injection of ethanol and octreotide increased pancreatic fibrosis. Unlike octreotide, ethanol provoked localized fibrosis that was maintained over time. It is expected that ethanol injection could eliminate POPF during pancreatic surgery.

关键词： Ethanol Octreotide Pancreatic fibrosis Pancreatic fistula Rat model

Ultimate strength of single shear bolted connections with cold-formed ferritic stainless steel

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第2期14卷 120-136页

作者： Jin-seong LIM tae-soo KIM Seung-hun KIM Department of Architectural Engineering Hanbat National UniversityDaejeon 305-719Korea

This paper is focused on the structural behavior of the single shear bolted connections with thin-walled ferritic stainless *** purpose of this study is to investigate the ultimate behaviors,such as ultimate strength and fracture mode of the single shear bolted connections of thin-walled ferritic stainless steel(low cost steel) rather than austenitic stainless steel(high cost steel).Bolt arrangement and end distance parallel to the direction of applied load are considered as main variables of the test specimens for bolted *** have a constant dimension of edge distance perpendicular to the loading direction,bolt diameter,pitch,and gauge.A monotonic tensile test for specimens has been carried out and some bolted connections with long end distance showed curling(out of plane deformation) occurrence which led to strength *** ultimate behaviors such as fracture mode,ultimate strength are compared with those predicted by current design ***,conditions of curling occurrence and the strength reduction due to curling are investigated and modified strength equations are suggested considering the curling effect.

关键词： Cold-formed ferritic stainless steel Bolted connection Bolt arrangement End distance Curling Strength reduction

Influence of operational parameters on the photocatalytic performance of DE-NOx process Via MIL-101(Fe)

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Progress in Natural Science:Materials International 2018年第6期28卷 689-695页

作者： Hoang Phuc Nguyen tae Ho Kim soo Wohn Lee Research Center for Eco Multi-Functional Nano Materials Sun Moon University Department of Environmental & Bio-Chemical Engineering Sun Moon University

Metal organic framework(MOF)has been paid great attention as a potential candidate for various applications in the field of energy and environment,particularly in air *** various MOFs,MIL-101(Fe) represents an interesting material possessing many advantages,including the ease of fabrication,high porosity,high specific surface area with open metal sites,making it a promising material in the field of harmful gas *** these advantages,MIL-101(Fe) was synthesized by facile microwave-solvothermal method and applied as a photocatalyst for the degradation of *** de-NOxefficiency of the synthesized powder was evaluated with respect to various operating parameters including substrates,sample doses,light spectrum and light intensity,initial NO concentration,and relative *** results have shown that the efficiency of NOxphotocatalytic degradation reaches to 77%under solar irradiation via 0.1 g of MIL-101(Fe) with optimum condition of reaction,(alumina substrate,350 ppb of initial NO concentration,40–50%of relative humidity).Then this work provides the optimum condition for the efficient photocatalytic degradation of NOx.

关键词： Metal-organic framework MIL-101 Gaseous pollutant NOx emission Photocatalyst

Detection of Graphene Cracks By Electromagnetic Induction,Insensitive to Doping Level

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Computer Modeling in Engineering & Sciences 2019年第8期120卷 351-361页

作者： taeshik Yoon Sumin Kang tae Yeob Kang taek-soo Kim Department of Mechanical Engineering KAISTDaejeon 34141Korea Graphene Research Center KAISTDaejeon 34141Korea

Detection of cracks is a great concern in production and operation processes of graphene based devices to ensure uniform ***,we show a detection method for graphene cracks by electromagnetic *** time varying magnetic field leads to induced voltage signals on graphene,and the signals are detected by a *** measured level of induced voltage is correlated with the number of cracks in graphene *** correlation is attributed to the increasing inductive characteristic of defective graphene,and it is verified by electromagnetic simulation and radio frequency ***,we demonstrate that the induced voltage signal is insensitive to the doping level of *** work can potentially lead to the development of a high-throughput and reliable crack inspection technique for mass production of graphene applications.

关键词： Graphene,crack detection inductance electromagnetic induction insensitive to doping

3D designed battery-free wireless origami pressure sensor

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Microsystems & Nanoengineering 2022年第6期8卷 35-46页

作者： taeil Kim Amirhossein Hassanpoor Kalhori tae-Ho Kim Chao Bao Woo soo Kim Additive Manufacturing Laboratory School of Mechatronic Systems EngineeringSimon Fraser UniversitySurrey V3T 0A3 BCCanada

A pressure monitoring structure is a very useful element for a wearable device for health monitoring and sports *** pressure sensors have been studied extensively,battery-free functions working in wireless detection have not been studied ***,we report a 3D-structured origami-based architecture sensor for wireless pressure *** developed an architectured platform for wireless pressure sensing through inductorcapacitor(LC)sensors and a monopole antenna.A personalized smart insole with Miura-ori origami designs has been 3D printed together with conductive 3D printed sensors *** monitoring of resonant frequency and intensity changes of LC sensors have been demonstrated to monitor foot pressure for different *** sensitivity of the wireless pressure sensor is tunable from 15.7 to 2.1 MHz/kPa in the pressure ranges from 0 to 9 kPa and from 10 to 40 kPa,*** proposed wireless pressure-sensing platform can be utilized for various applications such as orthotics,prosthetics,and sports gear.

关键词： battery free utilized