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Use of a Digital Image Correlation Technique for Measuring the Material Properties of Beetle Wing

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Journal of Bionic Engineering 2009年第3期6卷 224-231页

作者： Tailie Jin Nam Seo Goo sung-Choong Woo Hoon cheol Park Biomemitics and Intelligent Microsystem Laboratory Department of Advanced Technology FusionKonkuk University

Beetle wings are very specialized flight organs consisting of the veins and *** it is necessary from a bionic view to investigate the material properties of a beetle wing *** the present study,we have used a Digital Image Correlation (DIC) technique to measure the elastic modulus of a beetle wing *** were prepared by carefully cutting a beetle hind wing into 3.0 mm by 7.0 mm segments (the gage length was 5 mm).We used a scanning electron microscope for a precise measurement of the thickness of the beetle wing *** specimen was attached to a designed fixture to induce a uniform displacement by means of a *** used an ARAMISTM system based on the digital image correlation technique to measure the corresponding displacement of a *** thickness of the beetle wing varied at different points of the *** elastic modulus differed in relation to the membrane arrangement showing a structural anisotropy;the elastic modulus in the chordwise direction is approximately 2.65 GPa,which is three times larger than the elastic modulus in the spanwise direction of 0.84 *** a result,the digital image correlation-based ARAMIS system was suc- cessfully used to measure the elastic modulus of a beetle *** addition to membrane's elastic modulus,we considered the Poisson's ratio of the membrane and measured the elastic modulus of a vein using an Instron universal tensile *** result reveals the Poisson's ratio is nearly zero and the elastic modulus of a vein is about 11 GPa.

关键词： digital image correlation technique beetle wing elastic modulus Poisson's ratio vein membrane

Influence of undissolved second-phase particles on dynamic recrystallization behavior of Mg–7Sn–1Al–1Zn alloy during low-and high-temperature extrusions

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Journal of Materials Science & Technology 2021年第12期71卷 87-97页

作者： Hyun Ji Kim Sang-cheol Jin Jae-Gil Jung sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu41566Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon51508Republic of Korea

This study investigates the effects of fine and coarse undissolved particles in a billet of the Mg–7 Sn–1 Al–1 Zn(TAZ711)alloy on the dynamic recrystallization(DRX)behavior during hot extrusion at low and high temperatures and the resultant microstructure and mechanical properties of the *** this end,partially homogenized(PH)and fully homogenized(FH)billets are extruded at temperatures of250 and 450°*** PH billet contains fine and coarse undissolved Mg_(2) Sn particles in the interdendritic region and along the grain boundaries,*** fine particles(<1μm in size)retard DRX during extrusion at 250°C via the Zener pinning effect,and this retardation causes a decrease in the area fraction of dynamically recrystallized(DRXed)grains of the extruded *** addition,the inhomogeneous distribution of fine particles in the PH billet leads to the formation of a bimodal DRXed grain structure with excessively grown grains in particle-scarce *** contrast,in the FH billet,numerous nanosized Mg_(2) Sn precipitates are formed throughout the material during extrusion at 250°C,which,in turn,leads to the formation of small,uniform DRXed grains by the grain-boundary pinning effect of the *** the PH billet is extruded at the high temperature of 450°C,the retardation effect of the fine particles on DRX is weakened by their dissolution in theα-Mg matrix and the increased extent of thermally activated grain-boundary *** contrast,the coarse Mg_(2) Sn particles in the billet promote DRX during extrusion through the particle-stimulated nucleation phenomenon,which results in an increase in the area fraction of DRXed *** both low and high extrusion temperatures,the extruded material fabricated using the PH billet,which contains both fine and coarse undissolved particles,has a lower tensile strength than that fabricated using the FH billet,which is virtually devoid of second-phase *** lower strength of the former is attributed mai

关键词： Mg–Sn alloy Second-phase particle Extrusion Homogenization Dynamic recrystallization

Clinical implications and perspectives of portal venous circulating tumor cells in pancreatic cancer

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World Journal of Gastrointestinal Oncology 2023年第4期15卷 632-643页

作者： sung Woo Ko Seung Bae yoon Department of Internal Medicine College of MedicineThe Catholic University of KoreaSeoul 06591South Korea Department of Internal Medicine Eunpyeong St.Mary’s HospitalSeoul 03312South Korea

Despite recent improvements in the diagnosis and treatment of pancreatic cancer(PC),clinical outcomes remain ***,there are no effective prognostic or predictive biomarkers or options beyond carbohydrate antigen 19-9 for personalized and precise *** tumor cells(CTCs),as a member of the liquid biopsy family,could be a promising biomarker;however,the rarity of CTCs in peripheral venous blood limits their clinical *** the first venous drainage of PC is portal circulation,the portal vein can be a more suitable location for the detection of *** ultrasound-guided portal venous sampling of CTCs is both feasible and *** studies have suggested that the detection rate and number of CTCs may be higher in the portal blood than in the peripheral *** counts in the portal blood are highly associated with hepatic metastasis,recurrence after surgery,and *** phenotypic and genotypic properties measured in the captured portal CTCs can help us to understand tumor heterogeneity and predict the prognosis of *** sample sizes and heterogeneous CTC detection methods limit the studies to ***,a large number of prospective studies are needed to corroborate portal CTCs as a valid biomarker in PC.

关键词： Circulating tumor cell Pancreatic cancer Portal vein Outcomes Prognosis Survival

Anti-integrin therapy for inflammatory bowel disease

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World Journal of Gastroenterology 2018年第17期24卷 1868-1880页

作者： sung Chul Park yoon Tae Jeen Division of Gastroenterology and Hepatology Department of Internal Medicine Kangwon National University School of Medicine Division of Gastroenterology and Hepatology Department of Internal Medicine Korea University Anam Hospital orea University College of Medicine

In inflammatory bowel disease(IBD), tumor necro-sis factor plays an important role in mediating infla-mmation, but several other pathways are also involved in eliciting an inflammatory response. One such pathway is the invasion of the intestinal mucosa by leukocytes. Leukocytes within the systemic circulation move to sites of inflammation, and blocking this pathway could be an important treatment strategy for IBD. Anti-integrin therapy blocks the action of integrin on the surface of circulating immune cells and endothelial cell adhesion molecules, thereby inhibiting the interactions between leukocytes and intestinal blood vessels. Natalizumab, which acts on α4-integrin, was the first such drug to be approved for Crohn's disease, but its use is limited due to the risk of progressive multifocal leukoencephalopathy. Vedolizumab produces few systemic adverse effects because it acts on gut-trophic α4β7 integrin, and has been approved and is being used to treat IBD. Currently, several anti-integrin drugs, including etrolizumab, which acts on β7-integrin, and PF-00547569, which targets mucosal addressin cell adhesion molecule-1, are undergoing clinical trials and the results are being closely watched.

关键词： Integrin Ulcerative colitis Crohn’s disease Natalizumab Abrilumab Etrolizumab PF-00547659 Inflammatory bowel disease AJM300 Vedolizumab

Zero-static-power nonvolatile logic-in-memory circuits for flexible electronics

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Nano Research 2017年第7期10卷 2459-2470页

作者： Byung ChulJang Sang yoon Yang Hyejeong seong sung Kyu Kim Junhwan Choi sung Gap Im sung-Yool Choi School of Electrical Engineering Graphene/2D Materials Research Center Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea Department of Chemical and Biomolecular Engineering Graphene/2D Materials Research Center Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea

Flexible logic circuits and memory with ultra-low static power consumption are in great demand for battery-powered flexible electronic systems. Here, we show that a flexible nonvolatile logic-in-memory circuit enabling normally-off computing can be implemented using a poly（1,3,5-trivinyl-l,3,5-trimethyl cyclotrisiloxane）（pV3D3）-based memristor array. Although memristive logic-in-memory circuits have been previously reported, the requirements of additional components and the large variation of memristors have limited demonstrations to simple gates within a few operation cycles on rigid substrates only. Using memristor-aided logic （MAGIC） architecture requiring only memristors and pV3D3-memristor with good uniformity on a flexible substrate, for the first time, we experimentally demonstrated our implementation of MAGIC-NOT and -NOR gates during multiple cycles and even under bent conditions. Other functions, such as OR, AND, NAND, and a half adder, are also realized by combinations of NOT and NOR gates within a crossbar array. This research advances the development of novel computing architecture with zero static power consumption for battery- powered flexible electronic systems.

关键词： memristor memristive logic circuit flexible nonvolatilelogic-in-memory circuit normally-off computing memristor-aided logic(MAGIC) architecture

Thermal deformation of aluminum alloy casting materials for tire mold by numerical analysis

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中国有色金属学会会刊：英文版 2012年第S3期22卷 859-863页

作者： Hee-sung yoon Je-Se CHOI Yool-Kwon OH Department of Advanced Parts and Materials Engineering Chosun University Department of Mechatronics Engineering Chosun University

Thermal deformation of aluminum alloy casting materials for manufacturing the tire mold was numerically *** AC7A and AC4C casting material was selected as casting material and the metal casting device was used in order to manufacture the mold product of automobile tire in the actual industrial *** temperature distribution and the cooling time of casting materials were numerically calculated by finite element analysis (FEA).Also,the thermal deformation such as displacement and stress distribution was calculated from the temperature *** thermal deformation was closely related to the temperature difference between the surface and inside of the *** numerical analysis results reveal that the thermal deformation of AC7A casting material is higher than that of AC4C casting ***,the thermal deformation results at the central part are larger than that on the side of casting because of the shrinkage caused by the cooling speed difference.

关键词： thermal deformation finite element analysis AC7A casting material AC4C casting material

Injury of the arcuate fasciculus in a patient with progressive bulbar palsy

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Neural Regeneration Research 2016年第12期11卷 2031-2032页

作者： Min cheol Chang Han Do Lee sung Ho Jang Department of Physical Medicine and Rehabilitation College of MedicineYeungnam University

The arcuate fasciculus is the neural tract connecting the two major speech centers（Broca’s and Wernicke’s areas）and plays a critical role in language function（Catani and Mesulam,2008）.Injury of this tract can lead to several types of language impairment,including conduction aphasia,Broca’s aphasia,anomic aphasia,and apraxia of speech（Anderson et al.,1999;Bartha and Benke,2003;Catani and Mesulam,2008;Bernal and Ardila,2009;Kim et al.,2011）.

关键词： arcuate patient progressive

Ultra-flexible graphene/nylon/PDMS coaxial fiber-shaped multifunctional sensor

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Nano Research 2023年第4期16卷 5541-5547页

作者： Peddathimula Puneetha Siva Pratap Reddy Mallem sung cheol Park Seoha Kim Dong Hun Heo cheol Min Kim Jaesool Shim sung Jin An Dong-Yeon Lee Kwi-Il Park Department of Robotics and Intelligent Machine Engineering/College of Mechanical and IT Engineering Yeungnam UniversityGyeongsan 38541Republic of Korea School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Advanced Material Research Center Kumoh National Institute of TechnologyGumi 39177Republic of Korea School of Mechanical Engineering Yeungnam UniversityGyeongsan 38541Republic of Korea Department of Materials Science and Engineering Kumoh National Institute of TechnologyGumi 39177Republic of Korea

The development of flexible and wearable devices is mainly required for tactile sensing;as such devices can adapt to complicated nonuniform surfaces,they can be applied to the human ***,it remains necessary to simultaneously achieve small-scale,portable,and stable developments in such ***,this work aims at fabricating a novel,lightweight,ultra-flexible,and fiber-shaped coaxial structure with a diameter of 0.51 mm using polydimethylsiloxane/graphene/nylon material,based on piezoresistive and triboelectric *** piezoresistive-based robotic-hand-controlled sensor thus realized exhibits a response time of 120 ms and a fast recovery time of 55 ***,the piezoresistive-based sensors effectively feature whisker/joystick-guided behaviors and also sense the human finger *** to the triboelectric-based selfpowered nanogenerator behavior,the resulting sensor can convert mechanical motion into electrical energy,without adversely affecting human ***,this triboelectric-based human finger sensor can be operated under different bending modes at specific ***,this multifunctional sensor is cost-effective and suitable for various applications,including robotichand-controlled operations in medical surgery,whisker/joystick motions in lightweight drone technology,and navigation with highsensitivity components.

关键词： extremely lightweight ultra-flexible piezoresistive/triboelectric sensor human-machine whisker

Effects of homogenization temperature on microstructure and mechanical properties of high-speed-extruded Mg–5Bi–3Al alloy

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Journal of Magnesium and Alloys 2022年第10期10卷 2833-2846页

作者： Jae Won Cha Sang-cheol Jin Jae-Gil Jung sung Hyuk Park School of Materials Science and Engineering Kyungpook National University80 DaehakroDaegu 41566Republic of Korea Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

This study investigates the effects of billet homogenization temperature on the dynamic recrystallization behavior during high-speed extrusion and resultant microstructure and tensile properties of the Mg–5Bi–3Al(BA53,wt%)*** billets homogenized at 350 and450℃(350H and 450H billets)are extruded at a high speed of 69 m/*** 350H billet has a relatively smaller grain size and a higher abundance of fine Mg3Bi2particles compared to the 450H *** extrusion of the 350H billet,enhanced dynamic recrystallization occurs as a result of its finer grains and abundance of particles,while the growth of recrystallized grains is suppressed by the grain-boundary pinning effect of ***,the extruded 350H material is characterized by smaller grains,relatively greater number of Mg3Bi2particles,and a higher internal strain energy than the extruded 450H *** tensile strength of the extruded 350H material is higher than that of the extruded 450H material owing to stronger grain-boundary hardening,particle hardening,and strain hardening *** extruded 350H material also exhibits a higher tensile elongation as its smaller grains inhibit the formation of crack-inducing undesirable twins during *** results from this study demonstrate that a decrease in the homogenization temperature from 450 to 350℃leads to improved strength and ductility in the high-speed-extruded BA53 material.

关键词： Mg–Bi–Al alloy High-speed extrusion Homogenization Dynamic recrystallization Tensile properties