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Parametric Study on Design Parameters of Water-running Robot Based on Dynamic Simulation

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Journal of Bionic Engineering 2018年第6期15卷 960-970页

作者： Hyungyu kim Yanheng Liu TaeWon seo Max Planck Institute for Intelligent Systems Stuttgart 70565 Germany School of Mechanical Engineering Yeungnam University Gyeongsan 38541 Republic of Korea School of Mechanical Engineering Hanyang University Seou104 763 Republic of Korea

There are many design parameters to determine a performance of a robot. Especially, in the case of the mobile robots, they requirc complicated motion at various environments to get high performances. In this sense, the analysis of the design parameters is the most important work to design an efficient mobile robot. In this study, we analyze the design parameters for the water-running robot. From the parametric study, we find some solutions to improve the performances of the robot. We derive dynamic equations for the water-running motion, and do a sensitivity analysis to understand the relationships between the parameters （frequency of the leg, stiffness of torsional springs that connects multi frames and mass of frames） and the performance of the water-running motion such as running speed and pitching stability. We use an orthogonal array to make various combinations of the parameters, and to reduce the number of a simulation process. As results, we summarize some solutions to improve the water-running motion. We are expecting that this study is going to be used to design robots that are operated on the water.

关键词： bioinspired robot water-running motion multi-body system dynamic simulation analysis of design parameters sensitivity analysis

One dimensional pea-shaped NiSe_(2) nanoparticles encapsulated in N-doped graphitic carbon fibers to boost redox reversibility in sodium-ion batteries

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Journal of Materials Science & Technology 2024年第1期168卷 215-226页

作者： Hyunjeong gim Achmad Yanuar Maulana Jiwon Choi Jungwook Song Boram Yun Yuri Jeong Nahyun An Myeongkee Park Cybelle M.Futalan Jongsik kim Department of Chemical Engineering(BK21 FOUR graduate Program) Dong-A UniversityBusan 49315Korea(the Republic of) Department of Chemistry Dong-A UniversityBusan 49315Korea(the Republic of) Department of Chemistry Pukyong National UniversityBusan 48513Korea(the Republic of) Institute of Civil Engineering University of the PhilippinesDiliman 1127Philippines

In recent years,sodium-ion batteries(SIBs)have emerged as a promising technology for energy storage systems(ESSs)because of the abundance and affordability of ***,metal selenides have been studied as promising high-performance conversion-type anode materials in *** them,nickel se-lenide(NiSe_(2))has received considerable attention due to its high theoretical capacity of 495 mAh g^(-1)and ***,it still suffers from poor cycling stability because of the low electrochemical reactivity,large volume expansion,and structural instability during *** address these challenges,NiSe_(2)nanoparticles encapsulated in N-doped graphitic carbon fibers(NiSe_(2)@NgCF)were synthesized by using ZIF-8 as a ***_(2)@NgCF showed a high discharge capacity of 558.3 mAh g^(-1)with a fading rate of 0.14%per cycle after 200 cycles at 0.5 A g^(-1)in 0.01-3.0 *** a very high current density of 5 A g^(-1),the capacity still displayed excellent long-term cycle life with a discharge capacity of 406.1 mAh g^(-1)with a fading rate of 0.016%per cycle after 3000 *** mechanism of the excellent electrochem-ical performance of NiSe_(2)@NgCF was thoroughly investigated by ex-situ XRD,TEM,and SEM ***,NiSe_(2)@NgCF//Na_(3)V_(2)(PO_(4))_(3)full-cell also delivered an excellent reversible capacity of 378.7 mAh g^(−1)at 0.1 A g^(−1)after 50 cycles,demonstrating its potential for practical application in SIBs.

关键词： Sodium-ion batteries Anode materials Nickel selenide N-doped graphitic carbon fibers One-dimensional electrode

Fabrication of Variable Optical Attenuator With Low Insertion Loss

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光学学报 2003年第S1期23卷 305-306页

作者： Yone-gon seo Yong-Tak kim Jemin kim Hyung-do Yoon Young-Min Im Korea Electronics Technology Institute 455-6 MaSan-Ri JinWi-Myon PyungTaek-Si KyungGi-Do Korea Department of Advanced Materials Engineering Sungkyunkwan University Jangan-gu Suwon 440-746 Korea

A voltage-controlled variable optical attenuator (VOA) based on silica-based planar lightwave circuits (PLC) was fabricated by flame hydrolysis deposition (FHD). The variable attenuator with Cr heater achieves 20dB attenuation with 318mW electrical power at 1550 nm. The insertion loss and the polarization dependent loss (PDL) at 0 attenuation are 1dB and 0.23dB, respectively.

关键词： electrical power insertion loss

Experimental and Modeling Studies on the Chemical Vapor Infiltration with Respect to the Effects of Thermal gradient and Other Operating Parameters

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Journal of Wuhan University of Technology(Materials Science) 2018年第3期33卷 525-532页

作者： Kyung do Joo do Hoon kim gui Yung Chung Department of Chemical Engineering Hong Ik University

Effects of operating parameters in the thermal gradient chemical vapor infiltration of propane such as thermal gradient, diffusion, infiltrations time, and concentration of propane were studied by focusing on the visualizations of the intrinsic effects of these parameters. A uniform deposition in the preform was obtained with a gradually increasing temperature along the gas flow. The uniformity of deposition through the preform got improved with increasing deposition time. Results of numerical modeling estimated the experimental data very well when the pre-exponential factor of the overall rate of carbon deposition from propane reported by Vaidyaraman[1] was multiplied by 4. The average density of a preform increased by about 3 times from 0.38 to 1.15 g/cm3 after 60 hr deposition with a thermal gradient under the conditions of 3% propane in nitrogen and 840 to 900 ℃.

关键词： Tg-CVI propane C/C composites uniform deposition mathematical modeling

TMAS:A transaction misbehavior analysis scheme for blockchain

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Blockchain(Research and Applications) 2024年第3期5卷 42-52页

作者： Shiyong Huang Xiaohan Hao Yani Sun Chenhuang Wu Huimin Li Wei Ren kim-Kwang Raymond Choo School of Computer Science China University of GeosciencesWuhan430074China Artificial Intelligence Thrust Information HubHong Kong University of Science and TechnologyGuangzhou511400China Yunnan Key Laboratory of Blockchain Application Technology Yunnan Innovation Institute of Beihang UniversityKunming650233China Fujian Key Laboratory of Financial Information Processing Putian UniversityPutian351100China Department of Information Systems and Cyber Security University of Texas at San AntonioSan AntonioTX 78249-0631USA

Blockchain-based cryptocurrencies,such as Bitcoins,are increasingly ***,the decentralized and anonymous nature of these currencies can also be(ab)used for nefarious activities such as money laundering,thus reinforcing the importance of designing tools to effectively detect malicious transaction *** this paper,we propose TMAS,a transaction misbehavior analysis scheme for blockchain-based ***,the proposed system includes ten features in the transaction graph,two heuristic money laundering models,and an analysis method for account linkage,which identifies accounts that are distinct but controlled by an identical *** evaluate the effectiveness of our proposed indicators and models,we analyze 100 million transactions and compute transaction features,and are able to identify a number of suspicious ***,the proposed methods can be applied to other cryptocurrencies,such as token-based cryptocurrencies(e.g.,Bitcoins)and account-based cryptocurrencies(e.g.,Ethereum).

关键词： Blockchain Anti-money laundering Bitcoin Cyptocurrency

Measurements of Formaldehyde and TVOC Emission from Paints and Coating Materials using Small Chamber Method for Building Composites

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Journal of Wuhan University of Technology(Materials Science) 2012年第1期27卷 120-125页

作者： Jin-A kim Sumin kim Hyun-Joong kim Janghoo seo National Instrumentation Center for Environmental Management Seoul National University Seoul 151-921 Republic of Korea Laboratory of Adhesion & Bio-Composites Program in Environmental Materials Science Seoul National University Seoul 151-921 Republic of Korea Building Environment & Materials Lab School of Architecture Soongsil University Seoul 156-743 Republic of Korea School of Architecture Chosun University Gwangju 507-759 Korea

An optimal test method for paint is proposed; additionally, the Field and Laboratory Emission Cell （FLEC） method used in Europe is applied as a substitute for the 20 L small chamber method. The emission factors of total volatile organic compounds （TVOC） and formaldehyde from oil-based paint, emulsion paint, and water-dispersion paint with a coating weight of 300 g/m2, cured for 24/48 hours, were measured using the 20 L small chamber method. The emission rate of TVOC and formaldehyde from all paints began to stabilize after approximately 7 days after 24/48 hours of curing even though Korean standards stipulate that paint should be measured and analyzed after the third day of application. The emission factor of TVOC and formaldehyde from oil-based, emulsion, and water-dispersion paints were also measured using the FLEC method. There was good correlation between the 20 L small chamber method and the FLEC method for oil-based, emulsion, and water-dispersion paint emissions. With the FLEC method, using paints prepared under identical conditions, the emission rate was stable 24 hours after installation of samples because the air flow rate of FLEC is much higher than that of a 20 L small chamber, and the relative cell volume of FLEC is much smaller than that of a 20 L small chamber.

关键词： formaldehyde TVOC paints coating materials FLEC

Rolling Stability Enhancement via Balancing Tail for a Water-running Robot

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Journal of Bionic Engineering 2015年第3期12卷 395-405页

作者： Hyungyu kim do.g gyu Lee TaeWon seo School of Mechanical Engineering Yeungnam University Gyeongsan 712-749 Republic of Korea

Running on water produces very energy-efficient and fast motion in water environments. Many studies have been performed to develop bio-inspired water-running robots. To achieve good performance, the lifting force is very important for a robot to be able to run on water. The loss of lifting force is associated with the rolling stability of the robot on water. The purpose of this study is to improve the rolling stability of a water-running robot through the periodic motion of a balancing tail. Kinematic analysis was performed to calculate the motions of the legs and the tail, and static analysis was performed to calculate the balancing effect of the tail motion. A numerical model was suggested to determine the dynamic performance of the robotic platform based on kinematic and static results. A simulation based on the numerical model was performed, and the results were compared with empirical data from a robot prototype. The simulation results are in good agreement with the experimental data in terms of rolling stability The lifting force has only a slight effect. The results of this study can be used as a guideline for designing a stable water-running robot.

关键词： water-running robot balancing tail rolling stability lifting force basilisk lizard

Vertically Integrated Electronics: New Opportunities from Emerging Materials and Devices

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Nano-Micro Letters 2022年第12期14卷 195-223页

作者： seo.gjae kim Juhyung seo Junhwan Choi Hocheon Yoo Department of Electronic Engineering Gachon University1342 Seongnam-daeroSujeong-guSeongnamGyeonggi-do 13120Republic of Korea Center of Bio-Integrated Electronics Northwestern UniversityEvanstonIL 60208USA Querrey Simpson Institute for Bioelectronics Northwestern UniversityEvanstonIL 60208USA Present Address:Department of Chemical Engineering Dankook University152 Jukjeon-roSuji-guYonginGyeonggi-do 16890Republic of Korea

Vertical three-dimensional(3D)integration is a highly attractive strategy to integrate a large number of transistor devices per unit *** approach has emerged to accommodate the higher demand of data processing capability and to circumvent the scaling limitation.A huge number of research efforts have been attempted to demonstrate vertically stacked electronics in the last two *** this review,we revisit materials and devices for the vertically integrated electronics with an emphasis on the emerging semiconductor materials that can be processable by bottom-up fabrication methods,which are suitable for future flexible and wearable *** vertically stacked integrated circuits are reviewed based on the semiconductor materials:organic semiconductors,carbon nanotubes,metal oxide semiconductors,and atomically thin two-dimensional materials including transi-tion metal *** features,device performance,and fabrication methods for 3D integration of the transistor based on each semiconductor are ***,we highlight recent advances that can be important milestones in the vertically integrated elec-tronics including advanced integrated circuits,sensors,and display *** are remaining challenges to overcome;however,we believe that the vertical 3D integration based on emerging semiconductor materials and devices can be a promising strategy for future electronics.

关键词： Vertical stacking Three-dimensional integration Metal routing Via-hole Two-dimensional semiconductors

The gas-to-Dust Relation in the Dark Cloud L1523-Observational Evidence for CO gas Depletion

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Chinese Journal of Astronomy and Astrophysics 2008年第6期8卷 686-692页

作者： H.g.kim B.g.kim J.H.Jung Korea Astronomy and Space Science Institute 61-1 Hwaam Yuseong Daejeon 305-348 Korea

Correlation between gas and dust column density has been studied for the dark globule L1523. The 13CO（J=1→0） emission is used for tracing the gas, and the IR emissions, for tracing the dust constituent. In order to match the beam resolution between the images, a beam de-convolution algorithm based on the Maximum Correlation Method （MCM） was applied on the Infrared Astronomical Satellite （IRAS） data. The morphology of 13CO column density map shows a close correlation to that of 100μm dust optical depth. The distribution of the optical depth at 100 μm follows that of gas column density more closely than does the flux map at either 60 or 100μm. The ratio of the 13CO column density to the 100μm optical depth shows a decreasing trend with increasing dust optical depth in the central part, indicating possible molecular gas condensation onto dust particles. The excessive decrease in the CO column density in the envelope may most probably be due to the photo-dissociation of CO molecules.

关键词： ISM: clouds ISM: dust ISM: molecules