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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 1-6页

作者： young-keun jeong Koichi NIIHARA National Core Research Center for Hybrid Materials Solution Pusan National University Nagaoka University of Technology

Al2O3/5%SiC nanocomposites were fabricated by pressureless sintering using MgO as a sintering aid and then post hot-isostatic pressed (HIP), which can subsequently break through the disadvantage of hot-pressing process. The MgO additive was able to promote the densification of the composites, but could not induce the grain growth of Al2O3 matrix due to the grain growth inhibition by nano-sized SiC particles. After HIP treatment, Al2O3/SiC nanocomposites achieved full densification and homogeneous distribution of nano-sized SiC particles. Moreover, the fracture morphology of HIP treated specimens was identical with that of the hot-pressed Al2O3/SiC nanocomposites showing complete transgranular fracture. Consequently, high fracture strength of 1 GPa was achieved for the Al2O3/5%SiC nanocomposites by pressureless sintering and post HIP process.

关键词：碳化硅复合材料热等静压常压烧结微观结构纳米复合材料纳米SiC颗粒氧化铝 HIP处理

Dielectrophoretic assembly of semiconducting single-walled carbon nanotube transistor

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 126-129页

作者： Se-Hun KWON young-keun jeong Soongeun KWON Myung-Chang KANG Hyung-Woo LEE National Core Research Center for Hybrid Materials Solution Pusan National University Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon 305-701 Korea

A novel burning technique for making a semiconducting single-walled carbon nanotubes (SWNTs) transistor assembled by the dielectrophoretic force was suggested. The fabrication process consisted of two steps. First, to align and attach a bundle of SWNTs between the source and drain, the alternating (AC) voltage was applied to the electrodes. When a bundle of SWNTs was connected between two electrodes, some of metallic nanotubes and semi-conducing nanotubes existed together. The second step is to burn the metallic SWNTS by applying the voltage between two electrodes. With increasing the voltage, more current flowed through the metallic SWNTs, thus, the metallic SWNTs burnt earlier than the semiconducting one. This technique enables to obtain only semi-conducting SWNTs connection in the transistor. Through the I—V characteristic graph, the moment of metallic SWNTs burning and the characteristic of semi-conducing nanotubes were verified.

关键词：碳纳米管晶体管单壁碳纳米管束半导体燃烧技术制造过程 SWNTs 管连接特性图

^(27)Al MAS-NMR study of inorganic polymer formation at ambient temperature

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 182-187页

作者： Sang-Wook AHN Hee-Soo LEE Wan-Hee YANG Jung-Woo LEE young-keun jeong National Core Research Center for Hybrid Materials Solution Pusan National University School of Material Science and Engineering Pusan National University INTChem Co. Ltd.

Inorganic polymers are a novel class of materials formed by the polymerization of silicon, aluminium and oxygen species to form an amorphous three-dimensional framework structure. The basis of this process is the alkaline solutions to induce a certain amount of Si and Al atoms to dissolve from a feedstock such as aluminosilicate. A study of 27Al MAS-NMR was carried out in an attempt to understand the reaction mechanism of the inorganic polymerization at ambient temperature. Scanning electron microscopy (SEM) and X-ray diffractometry (XRD) were also employed to establish the composition and microstructure of the inorganic polymerization. Specimens were prepared with different Al/Si mole ratios from the starting materials. The higher the Al content, the more sufficient the Al atoms that can combine with SiO4, and the longer the reaction time, the more the bonded Si—O—Al—O polymer structure, and then the higher the Al content, the fewer the octahedral Al with a uniform Si—O—Al—O structure in four directions, because four Al atoms are combined with SiO4, resulting in a uniform Si—O—Al—O structure in four directions. The results show that they have an amorphous microstructure.

关键词：无机高分子环境温度 MAS NMR 无机聚合物扫描电子显微镜框架结构聚合反应机理

Direct 4D printing of functionally graded hydrogel networks for biodegradable,untethered,and multimorphic soft robots

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International Journal of Extreme Manufacturing 2024年第2期6卷 407-416页

作者： Soo young Cho Dong Hae Ho Sae Byeok Jo jeong Ho Cho Department of Chemical and Biomolecular Engineering Yonsei UniversitySeoul 03722Republic of Korea Department of Mechanical Engineering Virginia TechBlacksburgVA 24061United States of America School of Chemical Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwon 16419Republic of Korea

Recent advances in functionally graded additive manufacturing(FGAM)technology have enabled the seamless hybridization of multiple functionalities in a single *** robotics can become one of the largest beneficiaries of these advances,through the design of a facile four-dimensional(4D)FGAM process that can grant an intelligent stimuli-responsive mechanical functionality to the printed ***,we present a simple binder jetting approach for the 4D printing of functionally graded porous multi-materials(FGMM)by introducing rationally designed graded multiphase feeder *** graded cross-linking agents gradually form stable porous network structures within aqueous polymer particles,enabling programmable hygroscopic deformation without complex mechanical ***,a systematic bed design incorporating additional functional agents enables a multi-stimuli-responsive and untethered soft robot with stark stimulus *** biodegradability of the proposed 4D-printed soft robot further ensures the sustainability of our approach,with immediate degradation rates of 96.6%within 72 *** proposed 4D printing concept for FGMMs can create new opportunities for intelligent and sustainable additive manufacturing in soft robotics.

关键词： intelligent and sustainable additive manufacturing multi-material four-dimensional printing untethered soft robot multi-stimuli-responsive soft robot biodegradable soft robotics

Characteristic evaluation of Al_2O_3/CNTs hybrid materials for micro-electrical discharge machining

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 28-32页

作者： Hyun-Seok TAK Chang-Seung HA Ho-Jun LEE Hyung-Woo LEE young-keun jeong Myung-Chang KANG National Core Research Center for Hybrid Materials Solution Pusan National University Department of Electrical Engineering Pusan National University

The characteristic evaluation of aluminum oxide (Al2O3)/carbon nanotubes (CNTs) hybrid composites for micro-electrical discharge machining (EDM) was described. Alumina matrix composites reinforced with CNTs were fabricated by a catalytic chemical vapor deposition method. Al2O3 composites with different CNT concentrations were synthesized. The electrical characteristic of Al2O3/CNTs composites was examined. These composites were machined by the EDM process according to the various EDM parameters, and the characteristics of machining were analyzed using field emission scanning electron microscope (FESEM). The electrical conductivity has a increasing tendency as the CNTs content is increased and has a critical point at 5% Al2O3 (volume fraction). In the machining accuracy, many tangles of CNT in Al2O3/CNTs composites cause violent spark. Thus, it causes the poor dimensional accuracy and circularity. The results show that conductivity of the materials and homogeneous distribution of CNTs in the matrix are important factors for micro-EDM of Al2O3/CNTs hybrid composites.

关键词：加工特性混合材料微细电火花加工混杂复合材料场发射扫描电子显微镜微放电催化化学气相沉积法碳纳米管

Acoustofluidic separation of prolate and spherical micro-objects

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Microsystems & Nanoengineering 2024年第1期10卷 217-230页

作者： Muhammad Soban Khan Mushtaq Ali Song Ha Lee keun young Jang Seong Jae Lee Jinsoo Park Department of Mechanical Engineering Chonnam National University77 Yongbong-roBuk-guGwangju 61186Republic of Korea Department of Polymer Engineering The University of Suwon17 Wauan-gilBongdam-eupHwaseongGyeonggi 18323Republic of Korea

Most microfluidic separation techniques rely largely on object size as a separation *** ability to separate micro-objects based on their shape is crucial in various biomedical and chemical ***,we develop an ondemand,label-free acoustofluidic method to separate prolate ellipsoids from spherical microparticles based on traveling surface acoustic wave-induced acoustic radiation force and *** freely rotating non-spherical microobjects were aligned under the progressive acoustic field by the counterrotating radiation torque,and the major axis of the prolate ellipsoids was parallel to the progressive wave *** specific alignment of the ellipsoidal particles resulted in a reduction in the cross-sectional area perpendicular to the wave *** a consequence,the acoustic backscattering decreased,resulting in a decreased magnitude of the radiation *** the variation in radiation force,which depended on the micro-object morphology enabled the acoustofluidic shape-based *** conducted numerical simulations for the wave scattering of spherical and prolate objects to elucidate the working mechanism underlying the proposed method.A series of experiments with polystyrene microspheres,prolate ellipsoids,and peanut-shaped microparticles were performed for *** quantitative analysis of the separation efficiency,we confirmed the high purity and high recovery rate of the proposed acoustofluidic shapebased separation of *** a bioparticle,we utilize Thalassiosira eccentrica to perform shape-based separation,as the species has a variety of potential applications in drug delivery,biosensing,nanofabrication,bioencapsulation and immunoisolation.

关键词： separation spherical rotating

Combined Insights from Leachate Structure and Microstructure Characteristics for Eating Quality of Convenience Rice Processed by Super-Heated and Pressurized Steam Technologies

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Rice science 2024年第4期31卷 475-488,I0035,I0036页

作者： Mingyo HA Hyo-young jeong Ju Hun LEE Hyun-Jung CHUNG Division of Food and Nutrition Chonnam National UniversityGwangju 61186South Korea Department of Biotechnology College of Life Sciences and BiotechnologyKorea UniversitySeoul 02841South Korea Division of Food Science&Culinary Arts Shinhan UniversityGyeonggi 11644South Korea

Convenience rice has become widely popular due to its easy availability for cooking. This study investigated the starch structure and composition of leachate and the microstructure of reheated convenience rice using novel processing technologies: super-heated steaming(SHS), auto-electric cooking(AEC), and pressurized-steam cooking(PSC). Additionally, the effect of two different target water contents(58% and 63%) was also evaluated. The PSC_63% sample had the highest total solids and amylopectin amount in the leachate. The amylopectin amount in the leachate differed significantly based on the targeted water content. Morphological characterization revealed that the swelling of starch and the coated layer on the surface of rice grains were most pronounced in the PSC_63% sample due to the pressure processing. The textural hardness of the AEC_58% sample was much higher than that of the other samples. The PSC_63% sample had the highest textural adhesiveness value, which can be attributed to the highest amylopectin amount in the leachate. Sensory characterization showed that the PSC_63% sample had the highest glossiness, whiteness, moistness, and overall acceptability. The principal component analysis score plots presented substantial differences in the leachate and textural and sensory characteristics of reheated convenience rice among the different processing technologies.

关键词： reheated convenience rice starch structure leachate multi-scale structure eating quality processing technology

Enhancement of porcine in vitro embryonic development through luteolin‑mediated activation of the Nrf2/Keap1 signaling pathway

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Journal of Animal Science and Biotechnology 2024年第2期15卷 600-613页

作者： Se-Been Jeon Pil-Soo jeong Min Ju Kim Hyo-Gu Kang Bong-Seok Song Sun-Uk Kim Seong-keun Cho Bo-Woong Sim Futuristic Animal Resource&Research Center(FARRC) Korea Research Institute of Bioscience and Biotechnology(KRIBB)Cheongju 28116Republic of Korea Department of Animal Science College of Natural Resources&Life SciencePusan National UniversityMiryang 50463Republic of Korea Department of Animal Science and Biotechnology College of Agriculture and Life ScienceChungnam National UniversityDaejeon 34134Republic of Korea Department of Functional Genomics University of Science and TechnologyDaejeon 34113Republic of Korea Department of Animal Science Life and Industry Convergence Research Institute(RICRI)College of Natural Resources&Life SciencePusan National UniversityMiryang 50463Republic of Korea

Background Oxidative stress,caused by an imbalance in the production and elimination of intracellular reactive oxygen species(ROS),has been recognized for its detrimental effects on mammalian embryonic ***(Lut)has been documented for its protective effects against oxidative stress in various ***,its specific role in embryonic development remains *** study aims to investigate the influence of Lut on porcine embryonic development and to elucidate the underlying *** After undergoing parthenogenetic activation(PA)or in vitro fertilization,embryos supplemented with 0.5μmol/L Lut displayed a significant enhancement in cleavage and blastocyst formation rates,with an increase in total cell numbers and a decrease in the apoptosis rate compared to the *** on D2 and D6 revealed that embryos with Lut supplementation had lower ROS levels and higher glutathione levels compared to the ***,Lut supplementation significantly augmented mitochondrial content and membrane ***,activation of the Nrf2/Keap1 signaling pathway was observed in embryos supplemented with Lut,leading to the upregulation of antioxidant-related gene transcription *** further validate the relationship between the Nrf2/Keap1 signaling pathway and effects of Lut in porcine embryonic development,we cultured PA embryos in a medium supplemented with brusatol,with or without the inclusion of *** positive effects of Lut on developmental competence were negated by brusatol *** Our findings indicate that Lut-mediated activation of the Nrf2/Keap1 signaling pathway contributes to the enhanced production of porcine embryos with high developmental competence,and offers insight into the mechanisms regulating early embryonic development.

关键词： Luteolin Mitochondrial function Nrf2/Keap1 signaling pathway Oxidative stress Porcine embryo development

Laser micromachining of CNT/Fe/Al_2O_3 nanocomposites

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中国有色金属学会会刊：英文版 2009年第B9期19卷 189-193页

作者： Kwang-Ryul KIM Byoung-Deog CHOI Jun-Sin YI Sung-Hak CHO Yong-Ho CHOA Dong-Soo SHIN Dong-Ho BAE Myung-Chang KANG young-keun jeong School of Information and Communication Engineering Sungkyunkwan University Korea Institute of Machinery and Materials Department of Chemical Engineering Hanyang University NANOBASE Inc. School of Mechanical Engineering Sungkyunkwan University National Core Research Center for Hybrid Materials Solution Pusan National University

CNT/Fe/Al2O3 mixed powders were synthesized from Fe/Al2O3 nanopowders using thermal CVD for the homogeneous dispersion of carbon nanotubes CNTs. CNTs consisted of MWNT, and the diameter was approximately 20-30 nm. After sintering, CNTs were homogenously located throughout Al2O3 grain boundary and were buckled. A femto-second laser installed with special optical systems was used for micromachining of the nanocomposites. The relationship between material ablation rate and energy fluence was theoretically investigated and compared with experimental results from cross-sectional SEM analysis. The nanocomposites which have higher content of CNT show a fairly good machining result due to its higher thermal conductivity and smaller grain size as well as lower light transmittance.

关键词：纳米复合材料激光光学系统热化学气相沉积碳纳米管 Al2O3 扫描电镜分析均匀分散纳米粉体

Programmable directional color dynamics using plasmonics

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Microsystems & Nanoengineering 2024年第1期10卷 325-334页

作者： Gyurin Kim Doeun Kim Soeun Ko Jang-Hwan Han Juhwan Kim Joo Hwan Ko young Min Song Hyeon-Ho jeong School of Electrical Engineering and Computer Science Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Department of Semiconductor Engineering Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Artificial Intelligence(AI)Graduate School Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea

Adaptive multicolor filters have emerged as key components for ensuring color accuracy and resolution in outdoor visual ***,the current state of this technology is still in its infancy and largely reliant on liquid crystal devices that require high voltage and bulky structural ***,we present a multicolor nanofilter consisting of multilayered‘active’plasmonic nanocomposites,wherein metallic nanoparticles are embedded within a conductive polymer *** nanocomposites are fabricated with a total thickness below 100 nm using a‘lithography-free’method at the wafer level,and they inherently exhibit three prominent optical modes,accompanying scattering phenomena that produce distinct dichroic reflection and transmission ***,a pivotal achievement is that all these colors are electrically manipulated with an applied external voltage of less than 1 V with 3.5 s of switching speed,encompassing the entire visible ***,this electrically programmable multicolor function enables the effective and dynamic modulation of the color temperature of white light across the warm-to-cool spectrum(3250 K-6250 K).This transformative capability is exceptionally valuable for enhancing the performance of outdoor optical devices that are independent of factors such as the sun’s elevation and prevailing weather conditions.

关键词： directional prevailing exceptional