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Dyna-QUF:Dyna-Q based univector field navigation for autonomous mobile robots in unknown environments

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Journal of Central South University 2013年第5期20卷 1178-1188页

作者： VIET Hoang-huu CHOI seung-yoon chung Tae-choong Department of Computer Engineering Kyung Hee University

A novel approach was presented to solve the navigation problem of autonomous mobile robots in unknown environments with dense obstacles based on a univector field method. In an obstacle-free environment, a robot is ensured to reach the goal position with the desired posture by following the univector field. Contrariwise, the univector field cannot guarantee that the robot will avoid obstacles in environments. In order to create an intelligent mobile robot being able to perform the obstacle avoidance task while following the univector field, Dyna-Q algorithm is developed to train the robot in learning moving directions to attain a collision-free path for its navigation. Simulations on the computer as well as experiments on the real world prove that the proposed algorithm is efficient for training the robot in reaching the goal position with the desired final orientation.

关键词：自主移动机器人环境导航智能移动机器人目标位置移动方向现实世界 Q算法

Analytic Feynman Integrals of Functionals in a Banach Algebra Involving the First Variation

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Chinese Annals of Mathematics,Series B 2016年第2期37卷 281-290页

作者： Hyun Soo chung Vu Kim TUAN seung Jun CHANG Department of Mathematics Dankook University Department of Mathematics University of West Georgia

This paper deals with the analytic Feynman integral of functionals on a Wiener space. First the authors establish the existence of the analytic Feynman integrals of functionals in a Banach algebra S_α. The authors then obtain a formula for the first variation of integrals. Finally, various analytic Feynman integration formulas involving the first variation are established.

关键词：巴拿赫代数积分泛函泛函分析费曼 Wiener空间积分公式

Defect engineering of ternary Cu-In-Se quantum dots for boosting photoelectrochemical hydrogen generation

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Carbon Energy 2023年第12期5卷 215-228页

作者： Shi Li Sung-Mok Jung Wookjin chung Joo-Won Seo Hwapyong Kim Soo Ik Park Hyo Cheol Lee Ji Su Han seung Beom Ha In Young Kim Su-Il In Jae-Yup Kim Jiwoong Yang Department of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)DaeguRepublic of Korea Department of Chemical Engineering Dankook UniversityYonginRepublic of Korea Department of Chemistry and Nanoscience College of Natural ScienceEwha Womans UniversitySeoulRepublic of Korea Energy Science and Engineering Research Center Daegu Gyeongbuk Institute of Science and Technology(DGIST)DaeguRepublic of Korea

Heavy-metal-free ternary Cu–In–Se quantum dots(CISe QDs)are promising for solar fuel production because of their low toxicity,tunable band gap,and high light absorption *** defects significantly affect the photophysical properties of QDs,the influence on photoelectrochemical hydrogen production is not well ***,we present the defect engineering of CISe QDs for efficient solar-energy *** acid–base reactions between metal halide–oleylamine complexes and oleylammonium selenocarbamate are modulated to achieve CISe QDs with the controlled amount of Cu vacancies without changing their *** them,CISe QDs with In/Cu=1.55 show the most outstanding photoelectrochemical hydrogen generation with excellent photocurrent density of up to 10.7 mA cm-2(at 0.6 VRHE),attributed to the suitable electronic band structures and enhanced carrier concentrations/lifetimes of the *** proposed method,which can effectively control the defects in heavy-metal-free ternary QDs,offers a deeper understanding of the effects of the defects and provides a practical approach to enhance photoelectrochemical hydrogen generation.

关键词： copper-indium-selenide defect engineering photoelectrochemical hydrogen generation quantum dots solar hydrogen

Efficient solar fuel production enabled by an iodide oxidation reaction on atomic layer deposited MoS_(2)

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Carbon Energy 2023年第12期5卷 200-214页

作者： Young Sun Park Gyumin Jang Inkyu Sohn Hyungsoo Lee Jeiwan Tan Juwon Yun Sunihl Ma Jeongyoub Lee Chan Uk Lee Subin Moon Hayoung Im seung-Min chung seungho Yu Hyungjun Kim Jooho Moon Department of Materials Science and Engineering Yonsei UniversitySeoulRepublic of Korea School of Electrical and Electronic Engineering Yonsei UniversitySeoulRepublic of Korea Energy Storage Research Center Korea Institute of Science and TechnologySeoulRepublic of Korea

Oxygen evolution reaction(OER)as a half-anodic reaction of water splitting hinders the overall reaction efficiency owing to its thermodynamic and kinetic *** oxidation reaction(IOR)with low thermodynamic barrier and rapid reaction kinetics is a promising alternative to the ***,we present a molybdenum disulfide(MoS_(2))electrocatalyst for a high-efficiency and remarkably durable anode enabling ***_(2)nanosheets deposited on a porous carbon paper via atomic layer deposition show an IOR current density of 10 mA cm^(–2)at an anodic potential of 0.63 V with respect to the reversible hydrogen electrode owing to the porous substrate as well as the intrinsic iodide oxidation capability of MoS_(2)as confirmed by theoretical *** lower positive potential applied to the MoS_(2)-based heterostructure during IOR electrocatalysis prevents deterioration of the active sites on MoS_(2),resulting in exceptional durability of 200 ***,we fabricate a two-electrode system comprising a MoS_(2)anode for IOR combined with a commercial Pt@C catalyst cathode for hydrogen evolution ***,the photovoltaic–electrochemical hydrogen production device comprising this electrolyzer and a single perovskite photovoltaic cell shows a record-high current density of 21 mA cm^(–2)at 1 sun under unbiased conditions.

关键词： iodide oxidation reaction molybdenum sulfide photovoltaic-electrochemical hydrogen production solar hydrogen

Rational design of ultrafine FeSe_(2) nanocrystals emb e dde d within hollow mesoporous carbon bowls for potassium-ion batteries with long-term cycling stability and high volumetric capacity

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Journal of Materials Science & Technology 2023年第12期143卷 129-139页

作者： Yu Jin Jang Hong Geun Oh seung-Keun Park Department of Advanced Materials Engineering Chung-Ang University4726Seodong-daeroDaedeok-myeonAnseong-siGyeonggi-do 17546Republic of Korea

Hollow structures are commonly used to alleviate the mechanical stress on electrode materials and to provide more active sites in potassium-ion batteries(KIBs).Nevertheless,the excessive internal voids within these structures significantly reduce the packing density of particles,resulting in a relatively low volumetric energy density of the fabricated electrodes,which is undesirable for practical *** designed a hollow mesoporous carbon bowl embedded with ultrafine bis(selanylidene)iron(FeSe 2)nanocrystals(FeSe 2@HMCB)via a controllable impregnation method and subsequent selenization pro-cess for high-performance *** as-obtained FeSe 2@HMCB can inherit the advantages of conventional hollow carbon-based composites,such as alleviation of volume variation in active materials,abundant ion storage sites,and high electrical ***,the bowl structure has a higher pack-ing density than the conventional hollow structure,resulting in a significant increase in the volumet-ric energy density of the fabricated *** of these advantages,the FeSe 2@HMCB exhibits a high,stable reversible capacity of 326 mA h g^(-1) even after 1000 cycles at 0.5 A g^(-1),and excellent rate capacities(182 mA h g^(-1) at 3.0 A g^(-1)).Compared with the hollow structured counterpart,the vol-umetric capacity(mA h cm−3)of FeSe 2@HMCB increased by 60%.Furthermore,a full cell consisting of FeSe 2@HMCB//Prussian blue(PB)exhibits excellent electrochemical performance(99 mA h g^(-1) after 100 cycles at 0.1 A g^(-1)).

关键词： Potassium-ion batteries Iron selenide Bowl-like structure Mesoporous carbon Anode material

Inhibition behavior of Tragia involucrata L. phenolic compounds against acidic medium corrosion in low carbon steel surface

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Chinese Journal of Chemical Engineering 2019年第3期27卷 717-725页

作者： Ill-Min chung seung-Hyun Kim Venkatesan Hemapriya Kathirvel Kalaiselvi Mayakrishnan Prabakaran Department of Crop Science College of sanghr Life Science Konkuk University Department of Chemistry PSGR Krishnammal College for Women

The antioxidant and anticorrosive effect of Tragia involucrate L.(T. involucrate L.) was evaluated to aid in finding new compounds which can be used for various purposes. The total phenolic(TPC) and flavonoid content(TFC),antioxidant activity(DPPH, reducing potential and phosphomolybdenum), and electrochemical measurements,Fourier transform infrared(FT-IR), UV–visible(UV–vis) spectral analysis, scanning electron microscopy/energydispersive X-ray spectroscopy(SEM–EDX) and atomic force microscopy(AFM) were done to analyze the potency and also the inhibition efficiency of T. involucrate L. against 1 mol·L^(-1) HCl on low carbon steel. The TPC(145.21 mg GAE·g^(-1)), TFC(52.32 mg QCE·g^(-1)) and antioxidant activities were found to be significant. The electrochemical studies performed by AC impedance measurements showed significant changes in impedance spectra without causing any change in Nyquist plots. An increase in charge transfer resistance(Rct) values, a blockage in active sites exhibiting cathodic and anodic inhibition shows the action of inhibitor on low carbon steel. This was later confirmed by FT-IR and UV–vis which showed variation in absorption band at 270 nm and273 nm(before immersion) and 208 and 281 nm(after immersion). The same was tested again by SEM–EDX through altered strength of iron and oxygen bands and using AFM by analyzing the change in average roughness values of low carbon steel before(61.65 nm) and after(97.87 nm) exposure to blank acid without inhibitor, while it was shifted to 81.58 nm in acid with inhibitor. All these results showed strong evidence adding values to T. involucrate L. plant extract in inhibiting corrosion on low carbon steel and by promoting antioxidant importance of the extract which helps in scavenging free radicals.

关键词： Tragia involucrate L Antioxidant Corrosion Adsorption Electrochemistry SEM–EDX–AFM

Lithium plating-free 1 ah-level high-voltage lithium-ion pouch battery via ambi-functional pentaerythritol disulfate

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能源化学:英文版 2023年第8期83卷 229-238,I0007页

作者： Dung Tien Tuan Vu Jinsol Im Jae-Hee Kim Jisoo Han Gyeong Jun chung Giang Thi Huong Nguyen Junhyeok Seo Minjae Kim Eui-Hyung Hwang Young-Gil Kwon Jae Wook Shin Kuk Young Cho seung-Wan Song Department of Chemical Engineering&Applied Chemistry Chungnam National UniversityDaejeon 34134Republic of Korea Department of Materials Science&Chemical Engineering Hanyang UniversityAnsan 15588Republic of Korea Fine Chem Co.Ltd. Daejeon 34365Republic of Korea d CSIM Co.Ltd. Yesan 32400Republic of Korea Dongwha Electrolyte Nonsan 32925Republic of Korea

Elevating the charge cut-off voltage beyond traditional 4.2 V is a commonly accepted technology to increase the energy density of Li-ion batteries(LIBs) but the risk of Li-dendrites and fire hazard increases as well. The use of ambi-functional additive, which forms stable solid electrolyte interphase(SEI) simultaneously at both cathode and anode, is a key to enabling a dendrites-free and well-working high-voltage LIB. Herein, a novel ambi-functional additive, pentaerythritol disulfate(PEDS), at 1 wt% without any other additive is demonstrated. We show the feasibility and high impacts of PEDS in forming lithium sulfateincorporated robust SEI layers at NCM523 cathode and graphite anode in 1 ah-level pouch cell under4.4 V, 25 °C and 0.1 C rate, which mitigates the high-voltage instability, metal-dissolution and cracks on NCM523 particles, and prevents Li-dendrites at graphite anode. Improved capacity retention of 83%after 300 cycles is thereby achieved, with respect to 69% with base electrolyte, offering a promising path toward the design of practical high-energy LIBs.

关键词： Lithium-ion pouch cell Lithium plating-free High-voltage Ambi-functional additive SEI layer

Automatic Discontinuity Classification of Wind-turbine Blades Using A-scan-based Convolutional Neural Network

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Journal of Modern Power Systems and Clean Energy 2021年第1期9卷 210-218页

作者： Jiyeon Choung Sun Lim seung Hwan Lim Su chung Chi Mun Ho Nam Korea Electronics Technology Institute 401-402Bucheon Technopark655Pyeongcheon-roWonmi-guBucheon-siGyeonggi-do 14502Korea Sam Yong Inspection Engineering Co.Ltd.

Recent development trends in wind power generation have increased the importance of the safe operation of wind-turbine blades(WTBs). To realize this objective, it is essential to inspect WTBs for any defects before they are placed into operation. However, conventional methods of fault inspection in WTBs can be rather difficult to implement, since complex curvatures that characterize the WTB structures must ensure accurate and reliable inspection. Moreover, it is considered useful if inspection results can be objectively and consistently classified and analyzed by an automated system and not by the subjective judgment of an inspector. To address this concern,the construction of a pressure-and shape-adaptive phased-array ultrasonic testing platform, which is controlled by a nanoengine operation system to inspect WTBs for internal defects, has been presented in this paper. An automatic classifier has been designed to detect discontinuities in WTBs by using an A-scanimaging-based convolutional neural network(CNN). The proposed CNN classifier design demonstrates a classification accuracy of nearly 99%. Results of the study demonstrate that the proposed CNN classifier is capable of automatically classifying the discontinuities of WTB with high accuracy, all of which could be considered as defect candidates.

关键词： Wind-turbine blade(WTB) blade inspection platform convolutional neural network(CNN) discontinuity phased-array ultrasonic testing(PAUT) A-scan

Rationally designed graphene channels for real-time sodium ion detection for electronic tongue

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InfoMat 2023年第7期5卷 43-58页

作者： chung Won Lee Sang Eon Jun seung Ju Kim Tae Hyung Lee Sol A.Lee Jin Wook Yang Jin Hyuk Cho Shinyoung Choi Cheol-joo Kim Soo Young Kim Ho Won Jang Department of Materials Science and Engineering Research Institute of Advanced MaterialsSeoul National UniversitySeoulRepublic of Korea Department of Materials Science and Engineering Korea UniversitySeoulRepublic of Korea Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)PohangRepublic of Korea Advanced Institute of Convergence Technology Seoul National UniversitySuwonRepublic of Korea

Monitoring taste-inducing ions and molecules continuously in liquids or solutions is of great considerable matter for the realization of the electronic tongue(E-tongue).Particularly from the five major tastes,the highly selective,sensitive detection of Na^(+)in real-time is *** is due to the saltiness of food is the key ingredient in most ***,existing Na^(+)detecting devices have relatively low performances of selectivity,sensitivity,and lack of on–off ***,conventional devices significantly deteriorate in capac-ity due to repetitive usage or lifetime shortage by degradation of the sensing ***,a graphene-based channel was rationally designed by the facile decoration of Calix[4]arene and Nafion to address this *** act as a receptor and a molecular sieve,respectively,to enhance selectivity and sensitivity and elon-gate the life expectancy of the *** device was merged with a microfluidic channel to control the injection and withdrawal of solutions to fulfill dynamic on–off *** fabricated device has highly selective,sensitive Na^(+)detection properties compared to other 10 molecule/ionic *** on–off functions of the device were available,also possesses a long lifespan of at least 220 ***,it can precisely discriminate real beverages containing Na^(+),which can be observed by principal component analysis *** features offer the possibility of ascending to a platform for E-tongues in near future.

关键词： electronic tongue graphene microfluidic channels Na^(+)sensors solution-gated field-effect transistors