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A Miniaturized Tadpole Robot Using an Electromagnetic Oscillatory Actuator

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Journal of Bionic Engineering 2015年第1期12卷 29-36页

作者： Bu Hyun Shin Kyung-Min lee seung-yop lee Department of Mechanical Engineering Hanbat National University Daejeon 305-719 Korea Convergence Technology Examination Division Korean Intellectual Property Office Daejeon 302-701 Korea Department of Mechanical Engineering Sogang University Seoul 121-742 Korea

In this paper, we propose a miniaturized tadpole-like robot using an electromagnetic oscillatory actuator. The electro- magnetic actuator has a simple structure with a moving-magnet type and the body size is 13 mm （length） × 11 mm （height） ×10 mm （width）. A tail has the thickness of 100 μm and the length of 20 mm which is twice of the body-length （BL）. The tail attached to the oscillatory actuator generates undulatory propulsion for the forward swimming. Moreover, the tadpole robot enables the change of the direction by controlling input signal pattems applied to the oscillatory actuator. Prototypes of the tadpole robot have been manufactured and the thrust force and swimming speed are measured to evaluate the performance of the biomimetic robot in water at various tail-beat frequencies. The maximum thrust force is 42 mN at the tail-beat frequency of 30 Hz with voltage of 3 V, enabling the tadpole robot to swim at the speed of 210 mm·s^-1 （6 BL·s^-1）. The tadpole robot can also change its moving direction with the angular velocity of 21 deg·s^-1 at the half pulse pattem of 30 Hz.

关键词： fish robot biomimetics tadpole robot electromagnetic actuator

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由边界控制的轴向运动弦的振动控制

木工机床 2009年第2期 23-28页

作者： seung-yop lee C. D. Mote Jr 王正南京林业大学木材工业学院

一根轴向运动弦的横向振动稳定性是通过随时间变化的,使用对边界的横向运动或者外部的边界力的控制来实现的。平移弦的全部机械能量是一个亚普诺夫函数,边界控制法则被设计用于分散弦的整个振动能量在左侧或者右侧的边界。一种最佳的反... 详细信息

一根轴向运动弦的横向振动稳定性是通过随时间变化的,使用对边界的横向运动或者外部的边界力的控制来实现的。平移弦的全部机械能量是一个亚普诺夫函数,边界控制法则被设计用于分散弦的整个振动能量在左侧或者右侧的边界。一种最佳的反馈可通过降低受边界条件影响的能量获得,是边界控制的张力与入射波的传播速率的比值。同样,所需的最大时间用来稳定系统中的最初的扰动造成的全部振动能量,就是波在弦的跨度范围内在撞击边界之前传播所需要的时间。通过能量准则的衰减比率和半群理论的使用,边界控制下的轴向运动弦的渐近线和指数稳定性被分析验证。模拟被用于证实平移弦稳定性的理论预测和最优边界控制。

关键词：最优边界控制轴向运动振动控制振动稳定性振动能量时间变化传播速率指数稳定性

Application of ferrate(VI) in the treatment of industrial wastes containing metal-complexed cyanides : A green treatment

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Journal of Environmental Sciences 2009年第10期21卷 1347-1352页

作者： seung-MOK lee DIWAKAR Tiwari Department of Environmental Engineering Kwandong University Department of Chemistry School of Physical Sciences Mizoram University

Ferrate（VI） was employed for the oxidation of cyanide （CN） and simultaneous removal of copper or nickel in the mixed/complexed systems of CN-Cu, CN-Ni, or CN-Cu-Ni. The degradation of CN （1.00 mmol/L） and removal of Cu （0.095 mmol/L） were investigated as a function of Fe（Ⅵ） doses from 0.3-2.00 mmol/L at pH 10.0. It was found that Fe（Ⅵ） could readily oxidize CN and the reduction of Fe（Ⅵ） into Fe（Ⅲ） might serve efficiently for the removal of free copper ions. The increase in Fe（Ⅵ） dose apparently favoured the CN oxidation as well as Cu removal. Moreover, the pH dependence study （pH 10.0-13.0） revealed that the oxidation of CN was almost unaffected in the studied pH range （10.0-13.0）, however, the maximum removal efficiency of Cu was obtained at pH 13.0. Similarly, treatment was carded out for CN-Ni system having the initial Ni concentration of 0.170 mmol/L and CN concentration of 1.00 mmol with Fe（Ⅵ） dose 2.00 mmol at various pH values （10.0-12.0）. Results showed a partial oxidation of CN and partial removal of Ni. It can be observed that Fe（Ⅵ） can partially degrade the CN-Ni complex in this pH range. Further, Fe（Ⅵ） was applied for the treatment of simulated industrial waste/effluent waters treatment containing CN, Cu, and Ni.

关键词： cyanide metal-complexed cyanide oxidation copper nickel ferrate(Ⅵ)

Synergistically coupling of Ni–Fe LDH arrays with hollow Co–Mo sulfide nanotriangles for highly efficient overall water splitting

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Rare Metals 2024年第2期43卷 522-532页

作者： Yun Jae lee seung-Keun Park Department of Advanced Materials Engineering Chung-Ang UniversityAnseongGyeonggi-do17546Republic of Korea Department of Intelligent Energy and Industry Chung-Ang University84 Heukseok-ro Dongjak-guSeoul06974Republic of Korea Western Seoul Center Korea Basic Science Institute150 Bugahyeon-roSeodaemun-guSeoul03759Republic of Korea

Developing bifunctional catalysts that can catalyze both oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)is pivotal to commercializing large-scale water ***,a novel hollow nanotriangle composed of NiFe LDH-CoMoS_(x) heterojunction(H-CMSx@NiFe LDH)is proposed as a highly efficient bifunctional electrocatalyst for both OER and *** fabricate a heterojunction system,ultra-thin nickel–iron layered double hydroxide(NiFe LDH)nanosheets are uniformly electrodeposited onto a metal–organic framework-derived hollow CoMoS_(x) *** strong coupling of CoMoS_(x) and NiFe LDH catalysts forms the intimate heterojunction interfaces to facilitate interfacial charge transfer,which is favorable to enhance the bifunctional catalytic ***,the large void of CoMoS_(x) nanotriangles and interconnected ultra-thin NiFe LDH nanosheets result in good electrolyte penetration and gas ***,the as-prepared H-CMSx@NiFe LDH on nickel foam(NF)exhibits an impressive catalytic activity and durability for OER and HER activities,delivering a current density of 100 mA·cm^(−2) at the small overpotentials of 214 and 299 mV in OER and HER,***,H-CMSx@NiFe LDH/NF proves to be an effective electrode for an alkaline electrolyzer,as a voltage of only 1.99 V is enough to achieve a current density voltage of only 1.99 V is enough to achieve a current density of 400 mA·cm^(−2) with no degradation in performance over 50 h.

关键词： Overall water splitting Metal-organic framework Molybdenum sulfide Layered double hydroxide Heterojunction

Improvement in Background Error Covariances Using Ensemble Forecasts for Assimilation of High-Resolution Satellite Data

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Advances in Atmospheric Sciences 2011年第4期28卷 758-774页

作者： seung-Woo lee Dong-Kyou lee School of Earth and Environmental Sciences Seoul National University

Satellite data obtained over synoptic data-sparse regions such as an ocean contribute toward improving the quality of the initial state of limited-area models. Background error covariances are crucial to the proper distribution of satellite-observed information in variational data assimilation. In the NMC （National Meteorological Center） method, background error covariances are underestimated over data-sparse regions such as an ocean because of small differences between different forecast times. Thus, it is necessary to reconstruct and tune the background error covariances so as to maximize the usefulness of the satellite data for the initial state of limited-area models, especially over an ocean where there is a lack of conventional data. In this study, we attempted to estimate background error covariances so as to provide adequate error statistics for data-sparse regions by using ensemble forecasts of optimal perturbations using bred vectors. The background error covariances estimated by the ensemble method reduced the overestimation of error amplitude obtained by the NMC method. By employing an appropriate horizontal length scale to exclude spurious correlations, the ensemble method produced better results than the NMC method in the assimilation of retrieved satellite data. Because the ensemble method distributes observed information over a limited local area, it would be more useful in the analysis of high-resolution satellite data. Accordingly, the performance of forecast models can be improved over the area where the satellite data are assimilated.

关键词： 3DVAR background error covariances retrieved satellite data assimilation ensemble forecasts.

Joint member angle limits of composite beams and CFT square columns

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Journal of Central South University 2013年第1期20卷 199-206页

作者： lee seung-Jo lee Kang-Guk Department of Architecture Chosun College of Science & Technology Research Center for Urban Affair Kyungil University

This work aims to understand the relationship between the member angle limit and the energy ratio for 24 test samples of composite beams and CFT square steel tube columns. This work also compares the formula applicability for member angle limit with the previous test result to provide the basic data for the design of composite beam-CFT column. The evaluation of the member angle limit was performed with concrete compressive strength (fC =22.16 MPa, 30.49 MPa), breadth-to-thickness ratio (B/t=25.0, 33.3, 43.5), and axial capacity ratio (N/N0=0, 0.3, 0.4, 0.5) as the main variables of the test samples. For the relationship between the member angle limit (Ru) and the energy ratio (ES/EC ), the test result shows that the energy ratio becomes lower as the axial capacity ratio and the breadth-to-thickness ratio increase. The energy ratio is lower for the Type B test sample compared with that of Types A and C. For the formula suggested by SATO, the test samples are distributed evenly for comparison between test values and the member angle limit; however, other formulas indicate a deviation. Specifically, for the comparison between R u,cal and R u (Test), Maeda's formula shows severe deviation.

关键词： square steel tube axial capacity ratio member angle limit breadth-to-thickness ratio

ZnO-Embedded Expanded Graphite Composite Anodes with Controlled Charge Storage Mechanism Enabling Operation of Lithium-Ion Batteries at Ultra-Low Temperatures

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Energy & Environmental Materials 2023年第4期6卷 31-39页

作者： Kun Ryu Michael J.lee Kyungbin lee seung Woo lee George W.Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlantaGA 30332USA

As lithium(Li)-ion batteries expand their applications,operating over a wide temperature range becomes increasingly ***,the lowtemperature performance of conventional graphite anodes is severely hampered by the poor diffusion kinetics of Li ions(Li^(+)).Here,zinc oxide(ZnO) nanoparticles are incorporated into the expanded graphite to improve Li^(+)diffusion kinetics,resulting in a significant improvement in lowtemperature *** ZnO-embedded expanded graphite anodes are investigated with different amounts of ZnO to establish the structurecharge storage mechanism-performance relationship with a focus on lowtemperature *** analysis reveals that the ZnOembedded expanded graphite anode with nano-sized ZnO maintains a large portion of the diffusion-controlled charge storage mechanism at an ultra-low temperature of-50℃ Due to this significantly enhanced Li^(+)diffusion rate,a full cell with the ZnO-embedded expanded graphite anode and a LiNi_(0.88)Co_(0.09)Al_(0.03)O_(2)cathode delivers high capacities of 176 mAh g^(-1)at20℃ and 86 mAh g^(-1)at-50℃ at a high rate of 1 *** outstanding low-temperature performance of the composite anode by improving the Li^(+)diffusion kinetics provides important scientific insights into the fundamental design principles of anodes for low-temperature Li-ion battery operation.

关键词： diffusive and capacitive charge storages expanded graphite composites anode lithium-ion battery low-temperature operation transition metal oxide

Gene expression profiling reveals sequential changes in gastric tubular adenoma and carcinoma in situ

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World Journal of Gastroenterology 2005年第13期11卷 1937-1945页

作者： Chang-Hee lee seung-Hyun Bang seung-Koo lee Kyu-Young Song In-Chul lee Asan Institute for Life Sciences Department of Biochemistry Department of Pathology

AIM: To analyze the expression profiles of premalignant and/or preclinical lesions of gastric ***: We analyzed the expression profiles of normal gastric pit, tubular adenoma and carcinoma in situ using microdissected cells from routine gastric biopsies. For the DNA microarray analysis of formalin-fixed samples,we developed a simple and reproducible RNA extraction and linear amplification procedure applying two polymerasebinding sites. The amplification procedure took only 8 h and yielded comparable DNA microarray data between formalin-fixed tissues and unfixed ***: In comparison with normal pit, adenoma/carcinoma showed 504 up-regulated and 29 down-regulated genes at the expected false significance rate 0.15%. The differential expression between adenoma and carcinoma in situ was subtle: 50 and 22 genes were up-, and down-regulated in carcinomas at the expected false significance rate of 0.61%, respectively. Differentially expressed genes were grouped according to patterns of the sequential changes for the 'tendency analysis' in the gastric mucosaadenoma-carcinoma ***: Groups of genes are shown to reflect the sequential expression changes in the early carcinogenic steps of stomach cancer. It is suggested that molecular carcinogenic pathways could be analyzed using routinely processed biopsies.

关键词： Premalignant lesion Predinical lesion Gastric cancer

Characteristics of bifurcation and buckling load of space truss in consideration of initial imperfection and load mode

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第3期14卷 206-218页

作者： Su-deok SHON seung-jae lee Kang-guk lee School of Architectural Engineering Korea University of Technology and Education1800 ChungjeolroCheonan ChungnamRepublic of Korea Research Center for Urban Affair Kyungil UniversityGyeongsan-city GyeongbukRepublic of Korea

This study investigated characteristics of bifurcation and critical buckling load by shape imperfection of space truss,which were sensitive to initial *** critical point and buckling load were computed by the analysis of the eigenvalues and determinants of the tangential stiffness *** two-free-nodes example and star dome were selected for the case study in order to examine the nodal buckling and global buckling by the sensitivity to the eigen buckling mode and the analyses of the influence,and characteristics of the parameters as defined by the load ratio of the center node and surrounding node,as well as rise-span ratio were *** sensitivity to the imperfection of the initial shape of the two-free-nodes example,which occurs due to snapping at the critical point,resulted in bifurcation before the limit point due to the buckling mode,and the buckling load was reduced by the increase in the amount of *** two sensitive buckling patterns of the numerical model are established by investigating the displaced position of the free nodes,and the asymmetric eigenmode greatly influenced the behavior of the imperfection shape whether it was at limit point or ***,the sensitive mode of the two-free-nodes example was similar to the in-extensional basis mechanism of a simplified *** star dome,which was used to examine the influence among several nodes,indicated that the influence of nodal buckling was greater than that of global buckling as the rise-span ratio was ***,global buckling is occurred with reaching bifurcation point as the value of load ratio was higher,and the buckling load level was about 50%-70% of load level at limit point.

关键词： Space truss Geometric nonlinearity Initial imperfection Snap-through Bifurcation Global buckling