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Pendulation reduction on ship-mounted container crane via T-S fuzzy model

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Journal of Central South University 2012年第1期19卷 163-167页

作者： JANG Jae hoon KWON Sung-Ha JEUNG Eun tae Department of Control and Instrumentation Changwon National UniversityChangwon 641-773Korea

Ship-mounted container cranes are challenging industrial applications of nonlinear pendulum-like systems with oscillating disturbance which can cause them *** wave-induced ship motion causes the hoisted container to swing during the transfer operation,the swing motion may be dangerously large and the operation must be *** order to reduce payload pendulation of ship-mounted crane,nonlinear dynamics of ship-mounted crane is derived and a control method using T-S fuzzy model is *** results are given to illustrate the validity of the proposed design method and pendulation of ship-mounted crane is reduced significantly.

关键词： ship-mounted crane disturbance pendulation control T-S fuzzy model

Multidimensional Hybrid Architecture Encapsulating Cobalt Oxide Nanoparticles into Carbon Nanotube Branched Nitrogen-Doped Reduced Graphene Oxide Networks for Lithium–Sulfur Batteries

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Energy & Environmental Materials 2022年第2期5卷 555-564页

作者： Jeong Seok Yeon Young Hun Ko tae Ho park Hyunyoung park Jongsoon Kim Ho Seok park School of Chemical Engineering College of EngineeringSungkyunkwan University2066Seobu-roJangan-guSuwon-si Gyeonggi-do 440-746Korea Advanced Batteries Research Center Korea Electronics Technology Institute25Saenari-roBundang-guSeongnam-si Gyeonggi-do 13509Korea Department of Energy Science Sungkyunkwan University2066Seobu-roJangan-guSuwon-si Gyeonggi-do 440-746Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan University2066SeoburoJangan-guSuwon 440-746South Korea

Lithium–sulfur batteries(LSBs)are regarded as promising candidates for the next-generation energy storage devices owing to their high-theoretical capacity(1675 mAh g^(−1))and affordable ***,several limitations of LSBs such as the lithium polysulfide shuttle,large volume expansion,and low electrical conductivity of sulfur need to be resolved for practical *** address these limitations,herein,a multidimensional architectured hybrid(Co@CNT/nG),where Co_(3)O_(4) nanoparticles are encapsulated into threedimensional(3D)porous N-doped reduced graphene oxide interconnected with carbon nanotube(CNT)branches,is synthesized through a simple pyrolysis *** synergistic effect achieved through the homogeneously distributed and encapsulated Co_(3)O_(4) nanoparticles,the interconnected CNT branches,and the 3D hierarchical porous structure and N-doping of Co@CNT/nG significantly suppresses the shuttle effect of lithium polysulfides and enhances the conversion redox kinetics for the improved sulfur *** validate this effect through various measurements including symmetric cells,Li_(2)S nucleation,shuttle currents,Tafel slopes,diffusion coefficients,and post-mortem ***,Co@CNT/nG-70S-based LSB cells achieve a high-specific capacity of 1193.1 mAh g^(−1) at 0.1 C and a low capacity decay rate of 0.030%per cycle for 700 cycles at 5 C,delivering a high areal capacity of 5.62 mAh cm^(−2) even with a loading of 6.5 mg cm^(−2).

关键词： graphene/CNT hybrid lithium-sulfur batteries multidimensional architecture nanoparticle encapsulation redox promoter

Efficacy and safety of conversion of percutaneous cholecystostomy to endoscopic transpapillary gallbladder stenting in high-risk surgical patients

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Hepatobiliary & Pancreatic Diseases International 2021年第5期20卷 478-484页

作者： Hyung Ku Chon Chan park Dong Eun park tae Hyeon Kim Division of Biliopancreas Department of Internal MedicineWonkwang University College of Medicine and Hospital895 MuwangRoIksanSouth Korea Institute of Wonkwang Medical Science Wonkwang University College of Medicine and HospitalIksanSouth Korea Department of Surgery Wonkwang University College of Medicine and HospitalIksanSouth Korea

Background:Endoscopic transpapillary gallbladder stenting(ETGBS)has been used as an alternative to percutaneous cholecystostomy in patients with acute cholecystitis who are considered unfit for ***,there are few data on the efficacy and safety of ETGBS replacement of percutaneous cholecystostomy in high-risk surgical *** study aimed to evaluate the feasibility,efficacy,and safety of ETGBS to replace percutaneous cholecystostomy in high-risk surgical ***:This single center retrospective study reviewed the data of patients who attempted ETGBS to replace percutaneous cholecystostomy between January 2017 and September *** technical success,clinical success,adverse events,and stent patency were ***:ETGBS was performed in 43 patients(24 male,mean age 80.7±7.4 years)to replace percutaneous cholecystostomy due to high surgical *** technical success rate and clinical success rate were 97.7%(42/43)and 90.5%(38/42),***-related adverse events and stent-related late adverse events occurred in 7.0%(3/43)and 11.6%(5/43),*** the patients who successfully underwent ETGBS(n=42),only one had recurrent acute cholecystitis during *** median stent patency was 415 days(interquartile range 240–528 days).Conclusions:ETGBS,as a secondary intervention for the purpose of internalizing gallbladder drainage in patients following placement of a percutaneous cholecystostomy,is safe,effective,and technically ***,conversion of percutaneous cholecystostomy to ETGBS may be considered as a viable option in high-risk surgical patients.

关键词： Cholecystitis Percutaneous cholecystostomy Endoscopic transpapillary gallbladder stenting High surgical risk

Adaptive Functional Projective Lag Synchronization of a Hyperchaotic Rossler System

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Chinese Physics Letters 2009年第9期26卷 69-72页

作者： tae H. Lee Ju H. park Nonlinear Dynamics Group Department of Electrical Engineering Yeungnam University 214-1 Dae-Dong Kyongsan 712-749 Republic of Korea

We explain the functional projective lag synchronization of a hyperchaotic Rossler system with four unknown parameters, where the output of the master system lags behind the output of the slave system proportionally. Based on Lyapunov stability theory, an active control method and adaptive control law are employed to make the states of two hyperchaotic Rossler systems asymptotically synchronized. Finally, some numerical examples are provided to show the effectiveness of our results.

关键词： No English Keyword

Tribological properties of hierarchical micro-dimples produced on a cylindrical surface by dual-frequency texturing

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Friction 2023年第2期11卷 246-258页

作者： Saood ALI Rendi KURNIAWAN park Gun CHUL tae Jo KO School of Mechanical Engineering Yeungnam UniversityGyeongsan-si 712749Republic of Korea

An experimental investigation was performed for investigating the tribological performance of micro-dimple surface texture patterns on a cylindrical surface in a realistic operating environment of starved lubrication. Micro-dimples were generated by a dual-frequency surface texturing method, in which a high-frequency (16.3 kHz) three-dimensional (3D) vibration and a low-frequency (230 Hz) one-dimensional (1D) vibration were applied at the tool tip simultaneously, resulting in the generation of the hierarchical micro-dimples in a single step. Rotating cylinder-on-pin tribological tests were conducted to compare the tribological performance of the non-textured reference specimen and micro-dimple samples. The effect of surface textures generated with various shape parameters (long drop and short drop), dimension parameters (length and surface texture density), and operation parameters (load and sliding velocity) on the tribological performance was evaluated. Stribeck curves indicate that the hierarchical micro-dimples exhibit a lower coefficient of friction than the reference specimen in the high contact-pressure regions. It is also observed that variation in the length of a micro-dimple, the shape effect, is the major factor affecting the friction response of the textured surfaces. The generation of additional hydrodynamic pressure and lift effect by hierarchical structures is the main reason for the improved performance of hierarchical micro-dimple surfaces.

关键词： dual-frequency surface texturing hierarchical surfaces tribology starved lubrication three-dimensional elliptical vibration transducer

Environmental friendly synthesis of hierarchical mesoporous platinum nanoparticles templated by fucoidan biopolymer for enhanced hydrogen evolution reaction

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Journal of Materials Science & Technology 2020年第11期42卷 185-190页

作者： Seung Man Lim Kyunglee Kang Hongje Jang Jung tae park Department of Chemical Engineering Konkuk University120 Neungdong-roGwangjin-guSeoul 05029Republic of Korea Department of Chemistry Kwangwoon University20 Cwangwoon-roNowon-guSeoul 01897Republic of Korea

Researching novel hydrogen evolution reaction(HER)catalysts with enhanced electrocatalytic activity,excellent stability,and cost-efficiency is of great significance for the large-scale hydrogen production from industrial electrolysis *** report the preparation of hierarchical mesoporous-Pt nanoparticles(HM-Pt NPs)with coral-like rough surface morphologies using environmental friendly and biocompatible fucoidan(Fu)biopolymer as a surface engineering compound and its application to electrocatalysts for *** designed HM-Pt NPs yields better mass activity of electrocatalysts compared to a commercial Pt/***-Pt NPs showed an overpotential of 33 mV at 10 mA cm-2 for the HER in 0.5 MH2SO4,which was highly comparable to that of the commercial Pt/C catalysts(29 mV).However,the amount of HM-Pt NPs loaded in glassy carbon electrode(0.033 mg mL-1)was approximately 20 times lower than that of the commercial Pt/C(0.64 mg *** HM-Pt NPs also maintained high catalytic stability with a consistent HER current density after 1000 continuous *** excellent HER performance is attributed to the improved electrochemical surface area,highly porous structure,and good surface wettability of the HM-Pt NPs,which results in enhanced electrocatalytic activity,decreased resistance at the electrode/electrolyte interface,and facile penetration of the electrolytes inside the electrode.

关键词： Mesoporous Fucoidan Biopolymer Low Pt content Hydrogen evolution reaction

Effect of an Artificial Caudal Fin on the Performance of a Biomimetic Fish Robot Propelled by Piezoelectric Actuators

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Journal of Bionic Engineering 2007年第3期4卷 151-158页

作者： Seok Heo Tedy Wiguna hoon Cheol park Nam Seo Goo Artificial Muscle Research Center Konkuk UniversitySeoul 143-701Korea Department of Advanced Technology Fusion Konkuk UniversitySeoul 143-701Korea Department of Advanced Technology Fusion Artificial Muscle Research Center and Smart Robot CenterKonkuk UniversitySeoul 143-701Korea

This paper addresses the design of a biomimetic fish robot actuated by piezoeeramic actuators and the effect of artificial caudal fins on the fish robot＇s performance. The limited bending displacement produced by a lightweight piezocomposite actuator was amplified and transformed into a large tail beat motion by means of a linkage system. Caudal fins that mimic the shape of a mackerel fin were fabricated for the purpose of examining the effect of caudal fm characteristics on thrust production at an operating frequency range. The thickness distribution of a real mackerel＇s fin was measured and used to design artificial caudal fins. The thrust performance of the biomimetic fish robot propelled by fins of various thicknesses was examined in terms of the Strouhal number, the Froude number, the Reynolds number, and the power consumption. For the same fm area and aspect ratio, an artificial caudal fin with a distributed thickness shows the best forward speed and the least power consumption.

关键词： LIPCA biomimetic fish robot caudal fro Strouhal number Froude number Reynolds number

Comparison of Aerodynamic Forces and Moments Calculated by Three-dimensional Unsteady Blade Element Theory and Computational Fluid Dynamics

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Journal of Bionic Engineering 2017年第4期14卷 746-758页

作者： Loan Thi Kim Au Hoang Vu Phan hoon Cheol park Department of Advanced Technology Fusion and Artificial Muscle Research Center Konkuk University Seoul Korea

In previous work, we modified blade element theory by implementing three-dimensional wing kinematics and modeled the unsteady aerodynamic effects by adding the added mass and rotational forces. This method is referred to as Unsteady Blade Element Theory （UBET）. A comparison between UBET and Computational Fluid Dynamics （CFD） for flapping wings with high flapping frequencies （〉30 Hz） could not be found in literature survey. In this paper, UBET that considers the movement of pressure center in pitching-moment estimation was validated using the CFD method. We investigated three three-dimensional （3D） wing kinematics that produce negative, zero, and positive aerodynamic pitching moments. For all cases, the instantaneous aerodynamic forces and pitching moments estimated via UBET and CFD showed similar trends. The differences in average vertical forces and pitching moments about the center of gravity were about 10% and 12%, respectively. Therefore, UBET is proven to reasonably estimate the aerodynamic forces and pitching moment for flight dynamic study of FW-MAV. However, the differences in average wing drags and pitching moments about the feather axis were more than 20%. Since study of aerodynamic power requires reasonable estimation of wing drag and pitching moment about the feather axis, UBET needs further im- provement for hilzher accuracy.

关键词： blade element theory unsteady computational fluid dynamics flapping wings biomimetic

Structural,Sintering and Electrical Properties of Cr-doped La_(0.6)Sr_(0.4)Cr_xFe_(1-x)O_(3-δ)(x=0.10,0.20) Oxides

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Journal of Materials Science & Technology 2012年第7期28卷 654-660页

作者： LinlinZhu Jong Pyo Kim Sou Hwan Son Jung hoon park State Key SLaboratory of Catalysis.Dalian Institute of Chemical Physics Chinese~Academy of Sciences Dalian 116023 China Greenhouse Gas Research Center Climate Change Technology Research Division Korea Institute of Energy ResearchDaejeon 305-343 Korea College of Chemistry and Materials Science Liaoning University of Petroleum and Chemical Technology Fushun113001 China

The perovskite Cr-doped La0.6Sr0.4CrxFe1-xO3-δ （x=0.10, 0.20） oxides were synthesized via the citrate gel method. The perovskite forming of the Lao.6Sr0.4CrxFel-xO3-δ （x=0.10, 0.20） oxides were studied by ther- mogravimetric analysis （TG）, differential scanning calorimetry （DSC）, and X-ray diffraction （XRD）. Structural and chemical stability under H2-containing helium atmospheres of Lao.6Sro.4CrxFel-xO3-δ （x=0.10, 0.20） were investigated by TG and XRD. The sintering microstructures of the perovskite Lao.6Sr0.4Cr2Fel-xO3-δ （x--0.10, 0.20） ceramics were investigated by scanning electron microscopy （SEM）, and the electrical conduc- tivities of both oxide ceramics were also measured up to 900℃. The results demonstrated that the chemical stability of the Co-free ***.4CrxFe1-xO3-δ （x=0.10, 0.20） oxides was significantly improved compared to the Co-containing Lao.6Sr0.4C00.2Fe0.8O3-δ and Ba0.5Sr0.5Co0.8Fe0.2O3-δ oxides. The incorporation of Cr cations in the B-site of the pervoskite oxides resulted in the improved structural and chemical stability of the as-synthesized Lao.6Sr0.4CrxFe1-xO3-δ （x=0.10, 0.20） oxides.

关键词： Perovskite Crystal structure Sintering Electrical conductivity