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Ag-GST/HfO_(x)-based unidirectional threshold switching selector with low leakage current and threshold voltage distribution for high-density cross-point arrays

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Rare Metals 2024年第1期43卷 280-288页

作者： Kyoung-Joung Yoo Dae-yun Kang Nahyun Kim Ho-jin Lee Ta-hyeong Kim Taeho Kim Tae Geun Kim School of Electrical Engineering Korea UniversitySeoul 02841Republic of Korea

The use of electrochemical-metallization-based volatile threshold switching selectors in cross-point arrays has been widely explored owing to their high on-off ratios and simple ***,these devices are unsuitable for cross-point architectures because of the difficulty in controlling the random filament formation that results in large fluctuations in the threshold voltage during *** this study,we investigated the unidirectional threshold transition characteristics associated with an Ag/GST/HfO_(x)/Pt-based bilayer selector and demonstrated the occurrence of a low leakage current(<1×10^(-11) A) and low distribution of the threshold voltage(Δ0.11 V).The bilayer structure could control the filament formation in the intermediate state through the insertion of an HfO_(x) tunneling *** stacking a bilayer selector with NiO_(x)based resistive random-access memory,the leakage and programming currents of the device could be significantly *** the crossbar array configuration,we performed equivalent circuit analysis of a one-selector oneresistor(1S1R) devices and estimated the optimal array size to demonstrate the applicability of the proposed *** maximum acceptable crossbar array size of the 1S1R device with the Ag/GST/HfO_(x)/Pt/Ti/NiO_(x)/Pt structure was 5.29×10^(14)(N^(2),N=2.3×10^(7)).

关键词： Selector device Tunneling barrier Threshold switching Sputtering 1S1R Cross-point array

Design and analysis of electrothermal metasurfaces

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Frontiers in Energy 2023年第1期17卷 134-140页

作者： Xiu LIU Zhuo LI Zexiao WANG hyeong Seok yun Sheng SHEN Department of Mechanical Engineering Carnegie Mellon UniversityPittsburghPA 15213USA

Electrothermal metasurfaces have garneredconsiderable attention owing to their ability to dynamicallycontrol thermal infrared radiation. Although previousstudies were mainly focused on metasurfaces with infiniteunit cells, in practice, the finite-size effect can be a criticaldesign factor for developing thermal metasurfaces withfast response and broad temperature uniformity. Here, westudy the thermal metasurfaces consisting of goldnanorods with a finite array size, which can achieve aresonance close to that of the infinite case with onlyseveral periods. More importantly, such a small footprintdue to the finite array size yields response time down to ananosecond level. Furthermore, the number of the unitcells in the direction perpendicular to the axis of nanorodsis found to be insensitive to the resonance and responsetime;thus, providing a tunable aspect ratio that can boostthe temperature uniformity in the sub-Kelvin level.

关键词： modulated thermal infrared radiation metasurface nanosecond response time sub-Kelvin temperature uniformity finite size aspect ratio

Role of a wireless surface electromyography in dystonic gait in functional movement disorders: A case report

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World Journal of Clinical Cases 2020年第2期8卷 313-317页

作者： Min-Kyun Oh hyeong Seop Kim yun Jeong Jang Chang Han Lee Department of Rehabilitation Medicine Gyeongsang National University School of Medicine and Gyeongsang National University Hospital

BACKGROUND Dystonic gait(DG) is one of clinical symptoms associated with functional dystonia in the functional movement disorders(FMDs). Dystonia is often initiated or worsened by voluntary action and associated with overflow muscle activation. There is no report for DG in FMDs caused by an abnormal pattern in the ankle muscle recruitment strategy during *** SUMMARY A 52-year-old male patient presented with persistent limping gait. When we requested him to do dorsiflexion and plantar flexion of his ankle in the standing and seating positions, we didn’t see any abnormality. However, we could see the DG during the gait. There were no evidences of common peroneal neuropathy and L5 radiculopathy in the electrodiagnostic study. Magnetic resonance imaging of the lumbar spine, lower leg, and brain had no definite finding. No specific finding was seen in the neurologic examination. For further evaluation, a wireless surface electromyography(EMG) was performed. During the gait, EMG amplitude of left medial and lateral gastrocnemius(GCM) muscles was larger than right medial and lateral GCM muscles. When we analyzed EMG signals for each muscle, there were EMG bursts of double-contraction in the left medial and lateral GCM muscles, while EMG analysis of right medial and lateral GCM muscles noted regular bursts of single contraction. We could find a cause of DG in *** We report an importance of a wireless surface EMG, in which other examination didn’t reveal the cause of DG in FMDs.

关键词： Gait disorders Dystonic gait Surface electromyography Functional movement disorders Case report

Ameliorative effects of human adipose tissue-derived mesenchymal stem cells on myelin basic protein-induced experimental autoimmune encephalomyelitis in Lewis rats

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Neural Regeneration Research 2011年第16期6卷 1205-1210页

作者： Myung-Soon Ko hyeong-geun Park Young-Min yun Jeong Chan Ra Taekyun Shin Kyoung-Kap Lee College of Veterinary Medicine Jeju National University Stem Cell Research Center RNL BIO Co.Ltd.

Mesenchymal stem cells have been previously shown to exert an immunomodulatory function. The present study sought to investigate the effects of multipotential human adipose tissue-derived mesenchymal stem cells （hAdMSCs） on disease progression and cytokine expression in Lewis rats with experimental autoimmune encephalomyelitis （EAE） induced by myelin basic protein. The duration of EAE paralysis in the group treated on day 7 posfimmunization with 5 × 10^6 hAdMSCs was significantly reduced compared with the vehicle-treated controls and the 1 x 106 hAdMSC- treated group. The duration of EAE paralysis in the groups treated with 5 × 10^6 hAdMSCs on both day 1 and day 7 postimmunization was significantly reduced compared with the vehicle-treated controls and the groups treated with 5 × 10^6 hAdMSCs on both day 7 and day 10 postimmunization. The mRNA expression of interleukin-10 and indoleamine 2, 3-dioxygenase was significantly decreased in the hAdMSC-treated group compared with the vehicle-treated group. These findings suggest that the ameliorative effects of hAdMSCs on EAE symptoms operate in a dose- and time-dependent manner and can be mediated in part by the ample production of anti-inflammatory cytokines.

关键词： experimental autoimmune encephalomyelitis human adipose tissue mesenchymal stem cells intedeukin-10 interferon-gamma indoleamine 2, 3-dioxygenase neural regeneration

Nanoscale Materials and Deformable Device Designs for Bioinspired and Biointegrated Electronics

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Accounts of Materials Research 2021年第4期2卷 266-281页

作者： Woongchan Lee Huiwon yun Jun-Kyul Song Sung-Hyuk Sunwoo Dae-hyeong Kim Center for Nanoparticle Research Institute for Basic Science(IBS)Seoul 08826Republic of Korea School of Chemical and Biological Engineering Institute of Chemical ProcessesSeoul National UniversitySeoul 08826Republic of Korea

Electronic devices whose structural and functional features are inspired by living creatures have unique performance and unconventional features that are not found in conventional electronic *** addition to such bioinspired electronics,with the rise of new fields such as personalized healthcare,mobile electronics,and big-data analysis,biointegrated electronic devices that can collect biomedical information from the human body through various biosensors and deliver appropriate therapeutic feedback stimulations in real time on the spot where immediate treatment is needed have become *** body parts and internal organs of living creatures,including humans,have curvilinear shapes and comprise mechanically soft tissues,such bioinspired and biointegrated electronic devices are required to match the soft and deformable features of biological *** soft and deformable features of electronic devices can be achieved by employing flexible and stretchable materials and unconventional device design *** soft materials and deformable device designs dissipate stress originating from mechanical deformation of the device and thus retard crack generation and/or propagation in the ***,technologies for nanoscale materials have shown a significant level of progress on their material performance and processing *** nanoscale dimension of the electronic materials could achieve extremely small flexural rigidity in comparison to the bulk state of the same ***,techniques to form a well-percolated network of nanomaterials in the elastomeric matrix and to build a pathway for the facile electron and hole transport inside the polymer have induced dramatic performance advances of soft electronic materials,which led to nanocomposites that can accomplish both high mechanical deformability and high electrical performance at the same *** addition,deformable device designs such as buckled structures and serpentine des

关键词： buckling rigidity electronics

A strain-isolation design for stretchable electronics

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Acta Mechanica Sinica 2010年第6期26卷 881-888页

作者： Jian Wu Ming Li Wei-Qiu Chen Dae-hyeong Kim yun-Soung Kim Yong-Gang Huang Keh-Chih Hwang Zhan Kang John A.Rogers Departments of Civil and Environmental Engineering and Mechanical EngineeringNorthwestern University EvanstonIL 60208USA Department of Engineering Mechanics Dalian University of TechnologyDalian 116024China Department of Engineering Mechanics Zhejiang University Hangzhou 310058China Materials Research Laboratory Department of Materials Science and EngineeringBeckman Institute.University of Illinois UrbanaIL 61801USA AML Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China Departments of Chemistry Electrical and Computer Engineering and Mechanical Science and EngineeringUniversity of Illinois UrbanaIL 61801USA

Stretchable electronics represents a direction of recent development in next-generation semiconductor *** systems have the potential to offer the performance of conventional wafer-based technologies,but they can be stretched like a rubber band,twisted like a rope, bent over a pencil,and folded like a piece of *** the active devices from strains associated with such deformations is an important aspect of *** strategy involves the shielding of the electronics from deformation of the substrate through insertion of a compliant adhesive layer. This paper establishes a simple,analytical model and validates the results by the finite element *** results show that a relatively thick,compliant adhesive is effective to reduce the strain in the electronics,as is a relatively short film.

关键词： Strain isolation Thin film Substrate Adhesive Stretchable electronics

2D MoS2 Helical Liquid Crystalline Fibers for Multifunctional Wearable Sensors

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Advanced Fiber Materials 2024年第6期6卷 1813-1824页

作者： Jun Hyun Park Jang Hwan Kim Su Eon Lee Hyokyeong Kim Heo Yeon Lim Ji Sung Park Taeyeong yun jinyong Lee Simon Kim Ho Jun jin Kyeong Jun Park Heemin Kang Hoe Joon Kim hyeong Min jin Jiwoong Kim Sang Ouk Kim Bong Hoon Kim Department of Robotics and Mechatronics Engineering DGISTDaegu 42988Republic of Korea Present Address:Platform Technology R&D Center LG ChemistrySeoul 07795Republic of Korea Department of Materials Science and Engineering Soongsil UniversitySeoul 06978Republic of Korea Department of Organic Materials and Fiber Engineering Soongsil UniversitySeoul 06978Republic of Korea Nano Convergence Technology Research Center Korea Electronics Technology Institute(KETI)Gyeonggi‑do 13509Republic of Korea Department of Green Chemistry and Materials Engineering Soongsil UniversitySeoul 06978Republic of Korea Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea Department of Materials Science and Engineering National Creative Research Initiative Center for Multi‑Dimensional Directed Nanoscale AssemblyKAIST Institute for NanocenturyKAISTDaejeon 34141Republic of Korea Department of Organic Materials Engineering Chungnam National UniversityDaejeon 34134Republic of Korea Department of Materials Science and Engineering Chungnam National University99 Daehak‑roYuseong‑guDaejeon 34134Republic of Korea

Fiber-based material systems are emerging as key elements for next-generation wearable devices due to their remarkable advantages,including large mechanical deformability,breathability,and high ***,greatly improved mechani-cal stability has been established in functional fiber systems by introducing atomic-thick two-dimensional(2D)*** development of intelligent fibers that can respond to various external stimuli is strongly needed for versatile *** this work,helical-shaped semiconductive fibers capable of multifunctional sensing are obtained by wet-spinning MoS2 liquid crystal(LC)*** mechanical properties of the MoS2 fibers were improved by exploiting high-purity LC dispersions consisting of uniformly-sized MoS2 ***,three-dimensional(3D)helical fibers with structural chirality were successfully constructed by controlling the wet-spinning process *** helical fibers exhibited multifunctional sensing characteristics,including(1)photodetection,(2)pH monitoring,(3)gas detection,and(4)3D strain sensing.2D materials with semiconducting properties as well as abundant surface reactive sites enable smart multifunctionalities in one-dimensional(1D)and helical fiber geometry,which is potentially useful for diverse applications such as wearable internet of things(IoT)devices and soft robotics.

关键词： Molybdenum disulfide(MoS2) Liquid crystal(LC) Two-dimensional(2D)material Sensor Fiber

Overexpression of Arabidopsis YUCCA6 in Potato Results in High-Auxin Developmental Phenotypes and Enhanced Resistance to Water Deficit

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Molecular Plant 2013年第2期6卷 337-349页

作者： Jeong Im Kim Dongwon Baek hyeong Cheol Park Hyun jin Chun Dong-Ha Oh Min Kyung Lee Joon-yung Cha Woe-Yeon Kim Min Chul Kim Woo Sik Chung Hans J. Bohner Sang Yeol Lee Ray A. Bressan Shin-Woo Lee Dae-jin yun Department of Biochemistry Purdue University West Lafayette IN 47907 USA Division of Applied Life Science (BK21 and WCU Program) Plant Molecular Biology and Biotechnology Research Center Gyeongsang National UniversityJinju 660-701 Republic of Korea Department of Plant Biology University of Illinois at Urbana-Champaign Urbana IL USA Department of Agronomy and Medicinal Plant Resources Gyeongnam National University of Science and Technology Jinju 660-758 Korea Faculty of Science King Abdulaziz University Jeddah 21589 KSA Department of Horticulture Purdue University West Lafayette IN 47907 USA

Indole-3-acetic acid （IAA）, a major plant auxin, is produced in both tryptophan-dependent and tryptophan-independent pathways. A major pathway in Arabidopsis thaliana generates IAA in two reactions from tryptophan. Step one converts tryptophan to indole-3-pyruvic acid （IPA） by tryptophan aminotransferases followed by a rate-limiting step converting IPA to IAA catalyzed by YUCCA proteins. We identified eight putative StYUC （Solanum tuberosum YUCCA） genes whose deduced amino acid sequences share 50%-70% identity with those of Arabidopsis YUCCA proteins. All include canonical, conserved YUCCA sequences： FATGY motif, FMO signature sequence, and FAD-binding and NADP-binding sequences. In addition, five genes were found with -50% amino acid sequence identity to Arabidopsis trypto-phan aminotransferases. Transgenic potato （Solanum tuberosum cv. Jowon） constitutively overexpressing Arabidopsis AtYUC6 displayed high-auxin phenotypes such as narrow downward-curled leaves, increased height, erect stature, and longevity. Transgenic potato plants overexpressing AtYUC6 showed enhanced drought tolerance based on reduced water loss. The phenotype was correlated with reduced levels of reactive oxygen species in leaves. The results suggest a func-tional YUCCA pathway of auxin biosynthesis in potato that may be exploited to alter plant responses to the environment.

关键词： Solanum tuberosum potato Arabidopsis thaliana yuc6-1D YUCCA, StYUCCA, StTAA, auxin, drought.

Characteristics of nonvariceal upper gastrointestinal hemorrhage in patients with chronic kidney disease

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World Journal of Gastroenterology 2013年第43期19卷 7719-7725页

作者： Chang Seok Bang Yong Seop Lee yun hyeong Lee Hotaik Sung Hong Jun Park Hyun Soo Kim jin Bong Kim Gwang Ho Baik Yeon Soo Kim Jai Hoon Yoon Dong Joon Kim Ki Tae Suk Department of Internal Medicine Hallym University College of MedicineChuncheon 200-704South Korea Department of Biology Stanford UniversityStanfordCA 94305United States Department of Internal Medicine Yonsei University Wonju College of MedicineWonju 220-786South Korea

AIM:To evaluate the clinical characteristics of nonvariceal upper gastrointestinal hemorrhage(NGIH)in patients with chronic kidney disease(CKD).METHODS:From 2003 to 2010,a total of 72 CKD patients(male n=52,72.2%;female n=20,27.8%)who had undergone endoscopic treatments for NGIH were retrospectively *** findings,endoscopic features,prognosis,rebleeding risk factors,and mortality-related factors were *** characteristics of the patients and rebleeding-related data were recorded for the following variables:gender,age,alcohol use and smoking history,past hemorrhage history,endoscopic findings(the cause,location,and size of the hemorrhage and the hemorrhagic state),therapeutic options for endoscopy,endoscopist experience,clinical outcomes,and ***:The average size of the hemorrhagic site was 13.7±10.2 mm,and the most common hemorrhagic site in the stomach was the antrum(n=21,43.8%).The most frequent method of hemostasis was combination therapy(n=32,44.4%).The incidence of rebleeding was 37.5%(n=27),and 16.7%(n=12)of patients expired due to *** a multivariate analysis of the risk factors for rebleeding,alcoholism(OR=11.19,P=0.02),the experience of endoscopists(OR=0.56,P=0.03),and combination endoscopic therapy(OR=0.06,P=0.01)compared with monotherapy were significantly related to rebleeding after endoscopic *** a risk analysis of mortality after endoscopic therapy,only rebleeding was related to mortality(OR=7.1,P=0.02).CONCLUSION:Intensive combined endoscopic treatments by experienced endoscopists are necessary for the treatment of NGIH in patients with CKD,especially when a patient is an alcoholic.

关键词： Chronic kidney diseases Gastrointestinal hemorrhage Endoscopy Peptic ulcer Alcoholics