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Review on Tidal Energy Technologies and Research Subjects

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China Ocean Engineering 2020年第1期34卷 137-150页

作者： chul Hee JO Su Jin hwang Department of Naval Architecture and Ocean Engineering Inha University

Tidal current power is one of the promising and reliable renewable energies with the advantage of continuous and predictable resource. It can make stable electricity regardless of weather conditions or seasons all year around. The required technologies for tidal current power in the ocean have been developed for years and now recognized that it could be commercialized after intensive field tests and successful demonstrations. There are several tidal farm development projects in the world, such as the MeyGen project in UK with its commercialization at hand. However, various research subjects in the tidal current energy field are seeking improvements and industrialization of tidal current power in terms of economy and technical reliability. This paper introduces the resource assessment procedure of tidal energy that has been applied in Korea coastal regions. The key research subjects for tidal current power together with the interaction effect of multi-arrangement is described. Also, this paper is to introduce the research output of each subject such as turbine design, experimental validation, turbine interaction and wake, multi-array module, FSI (fluid-structure interaction), and duct application.

关键词： tidal current power resource assessment turbine design experimental validation turbine interaction multi arrangement FSI(fluid-structure interaction)

End-of-life batteries management and material flow analysis in South Korea

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Frontiers of Environmental Science & Engineering 2018年第3期12卷 55-67页

作者： Hyunhee Kim Yong-chul Jang Yeonjung hwang Youngjae Ko Hyunmyeong Yun Department of Environmental Engineering Chungnam National University Daejeon 34134 South Korea Waste to Energy Research Division Environmental Resources Research Department National Institute of Environmental Research Incheon 22689 South Korea Daejeon Green Environment Center Daejeon 34134 South Korea

Consumers increasingly have worn-out batteries as electrical and electronic equipment with new technical developments are introduced into the market and quickly replace older models. As a result, large amounts of end-of-life （EOL） or waste batteries are generated. Such batteries may contain a variety of materials that includes valuable resources as well as toxic elements. Thus, the proper recycling and management of batteries is very important from the perspective of resource conservation and environmental effect. The collection and recycling of EOL batteries is relatively low in South Korea compared to other countries, although an extended producer responsibility （EPR） policy was adopted for battery recycling in 2003. In this study, the management and material flow of EOL batteries is presented to determine potential problems and quantitative flow, based on literature review, site visits to battery recycling facilities, and interviews with experts in the Korea Battery Recycling Association （KBRA）, manufacturers, and regulators in government. The results show that approximately 558 tons of manganese-alkaline batteries, the largest fraction among recycling target items, was disposed in landfills or incinerators in 2015, while approximately 2,000 tons of batteries were recovered at a recycling facility by simple sorting and crushing processes. By raising environmental awareness, more diverse and effective collection systems could be established for consumers to easily dispose of EOL batteries in many places. Producers, retailers and distributors in South Korea should also play an important role in the collection of EOL batteries from consumers. Lithium-ion batteries from many electronic devices must be included in the EPR system for resource recovery.

关键词： End-of-life battery Recycling Material flow analysis (MFA)Extended producer responsibility (EPR)Resource recovery

Minimum Orders of Eulerian Oriented Digraphs with Given Diameter

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Acta Mathematica Sinica,English Series 2014年第7期30卷 1125-1132页

作者： Yoomi RHO Byeong Moon KIM Woonjae hwang Byung chul SONG Department of Mathematics University of Incheon Department of Mathematics Gangneung-Wonju National University Department of Information and Mathematics Korea University

A digraph D is oriented if it does not contain 2-cycles. If an oriented digraph D has a directed eulerian path, it is an oriented eulerian digraph. In this paper, when an oriented eulerian digraph D has minimum out-degree 2 and a diameter d, we find the minimum order of D. In addition, when D is 2-regular with diameter 4rn （m≥2）, we classify the extremal cases.

关键词： Oriented digraph eulerian digraph minimum order diameter

Relaxation of rabbit cavernous smooth muscle to 17β-estradiol: a non-genomic, NO-independent mechanism

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Asian Journal of Andrology 2004年第2期6卷 127-131页

作者： Sae-chul Kim Kyung-kun Seo Soon-chul Myung Moo Yeol Lee Department of Urology College of Medicine Chung-Ang University Seoul 140-757 KoreaDepartment of Urology College of Medicine Chung-Ang University Seoul 140-757 KoreaDepartment of Urology College of Medicine Chung-Ang University Seoul 140-757 KoreaDepartment of Physiology College of Medicine Chung-Ang University Seoul 140-757 Korea

Aim: To investigate whether estrogen was involved in relaxation of rabbit cavernous smooth muscle. Methods: Relaxation response of the rabbit cavernous smooth muscles to 17β-estradiol (0.3, 3, 30 and 300 nmol/L) were observed in vitro. The response of the muscle strips to estrogen after incubation with either actinomycin D (10μmol/L) or L-NAME (10μmol/L) were also evaluated. Inside-out mode of patch clamp in a single smooth muscle cell was applied to investigate the Maxi-K channel activities. Results: Estrogen caused a dose-dependent relaxation of the strips precontracted with norepinephrine. The maximal response was noted about 10 minutes after treatment. The estrogen-induced relaxation was prevented by neither actinomycin D nor L-NAME, suggesting that the response was not mediated by gene transcription or nitric oxide (NO). Application of 17β-estradiol increased the Maxi-K channel activities. Conclusion: 17β-estradiol may be involved in relaxation of rabbit cavernous smooth muscles via a non genomic and NO independent mechanism. 17β-estradiol stimulates Maxi-K channel of the rabbit cavernous myocyte.

关键词： 17β-estradiol cavernous smooth muscles Maxi-K channel relaxation

Comparison Study and Forensic Analysis between Experiment and Coupled Dynamics Simulation for Submerged Floating Tunnel Segment with Free Ends under Wave Excitations

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Computer Modeling in Engineering & Sciences 2023年第10期137卷 155-174页

作者： Woo chul Chung Chungkuk Jin Moo Hyun Kim Ju-young hwang Division of Mechanical Engineering Korea Maritime&Ocean UniversityBusanSouth Korea Department of Ocean Engineering and Marine Sciences Florida Institute of TechnologyMelbourneFLUSA Department of Ocean Engineering Texas A&M UniversityCollege StationTXUSA Department of Civil Engineering Dong-Eui UniversityBusanSouth Korea

This paper presents dynamic-behavior comparisons and related forensic analyses of a submerged floating tunnel(SFT)between numerical simulation and physical experiment under regular and irregular *** experiments are conducted in the 3Dwave tank with 1:33.3 scale,and the corresponding coupled time-domain simulation tool is devised for *** entire SFT systemconsists of a long concrete tunnel and 12 tubular aluminummooring *** numerical simulation models,the Cummins equation with 3D potential theory including second-order wave-body interaction effects and the much simpler Morison-equation-based formula with the lumped-massbased line model,are designed and *** analyses for mooring-line adjustments in the simulation are carried out in view of the best representation of the physical *** that,the measured pre-tension distribution and systemstiffness of twelvemooring lines arewell reproduced in the ***,the dynamic responses and mooring tensions of the SFT are compared under regular and irregular *** measured and simulated results coincide reasonably well for both regular-and irregular-wave conditions.

关键词： Submerged floating tunnel comparative study forensic analysis mooring-line modeling dynamic response mooring tension

Continuity control method of cutter posture vector for efficient five-axis machining

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Journal of Central South University 2011年第6期18卷 1969-1975页

作者： hwang Jong-dae KIM Sang-myung JUNG Hyun-chul JUNG Yoon-gyo School of Mechatronics Changwon National University

During five-axis machining of impeller, the excessive local interference avoidance leads to inconsistency of cutter posture, low quality of machined surface and increase of processing time. Therefore, in order to improve the efficiency of five-axis machining of impellers, it is necessary to minimize the cutter posture changes and create a continuous tool path while avoiding interference. By using an MC-space algorithm for interference avoidance, an MB-spline algorithm for continuous control was intended to create a five-axis machining tool path with excellent surface quality and economic feasibility. A five-axis cutting experiment was performed to verify the effectiveness of the continuity control. The result shows that the surface shape with continuous method is greatly improved, and the surface roughness is generally favorable. Consequently, the effectiveness of the suggested method is verified by identifying the improvement of efficiency of five-axis machining of an impeller in aspects of surface quality and machining time.

关键词： five-axis control machining configuration-space B-spline continuity control method impeller interference

Development of practical postprocessor for 5-axis machine tool with non-orthogonal rotary axes

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Journal of Central South University 2011年第1期18卷 159-164页

作者： JUNG Hyoun-chul hwang Jong-Dae PARK Ki-Beom JUNG Yoon-Gyo School of Mechatronics Changwon National University

In order to develop a practical postprocessor for 5-axis machine tool,the general equations of numerically controlled(NC) data for 5-axis configurations with non-orthogonal rotary axes were exactly expressed by the inverse kinematics,and a windows-based postprocessor written with Visual Basic was developed according to the proposed *** developed postprocessor is a general system suitable for all kinds of 5-axis machines with orthogonal and non-orthogonal rotary *** implementation of the developed postprocessor and verification by a cutting simulation and machining experiment,the effectiveness of the proposed algorithm is *** is improved by allowing exchange of data formats such as rotational total center position(RTCP) controlled NC data,vector post NC data,and program object file(POF) cutter location(CL) data,and convenience is increased by adding the function of work-piece origin ***,a practical post-processor for 5-axis machining is developed.

关键词： post-processor 5-axis machining non-orthogonal rotary axes numerically controlled (NC) data CL data

Flexible electronics based on one-dimensional and two-dimensional hybrid nanomaterials

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InfoMat 2020年第1期2卷 33-56页

作者： Jihun Park Jae chul hwang Gon Guk Kim Jang-Ung Park Department of Materials Science and Engineering Nano Science Technology InstituteYonsei UniversitySeoulRepublic of Korea Center for Nanomedicine Institute for Basic Science(IBS)Yonsei-IBS InstituteSeoulRepublic of Korea

Research on flexible or wearable electronics has been grown remarkably due to the advent of nanomaterials,such as metal nanowires,graphene,or transition metal *** each nanomaterial has mechanical and electrical characteristics that can be applied into flexible electronics,the limitations of each nanomaterial are also *** order to overcome the limitations of these nanomaterials,research on the hybrid structures of nanomaterials has been extensively *** this study,we introduce the properties of one-dimensional nanomaterials,twodimensional nanomaterials,and their hybrid *** then,we provide information concerning various flexible electronics based on these nanomaterials.

关键词： flexible electronics hybrid nanomaterials one-dimensional nanomaterials two-dimensional nanomaterials wearable electronics

Study of cerium-promoted rhodium alumina catalyst as a steam reforming catalyst for treatment of spent solvents

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Journal of Rare Earths 2014年第9期32卷 831-836页

作者： Hee-chul Yang Min-Woo Lee Ho-Sang hwang Jei-Kwon Moon Dong-Yong Chung Korea Atomic Energy Research Institute

This study attempted to develop an appropriate catalyst used for the steam reforming of gasified spent solvents. Rh2O3/ CeOE-Al2O3 catalysts with various CeO2 loadings were prepared and heated at different temperatures of 500 and 800 ℃, and their surface properties were studied using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, temperature programmed reduction （TPR） and Bmmauer-Emmett-Teller （BET） analyses. Rhodium existed in the form of Rh2O3, regardless of the sample composition as well as the heating temperature. In the tested range of cerium addition （up to 12 times the rhodium mass）, no significant changes in BET surface areas and binding energy corresponding to Rh 3d5/2 were observed. Instead, the addition of cerium led to a greatly enhanced dispersion of rhodium nanoparticles, and no agglomeration of rhodium was observed for samples heated even at 800 ℃. Honeycomb monolith rhodium catalysts promoted with cerium were fabricated and tested for the steam reforming of a gasified spent solvent, mainly consisting of butylene （C4H8）. The test results suggested that a cerium-promoted rhodium catalyst could be used as an appropriate reforming catalyst for treating low-quality non-methane hydrocarbons without the formation of coke at high temperatures of up to 900 ℃.

关键词： cerium rhodium catalyst steam reforming spent resin rare earths