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Recent Advances in Electrode Materials with Anion Redox Chemistry for Sodium-Ion Batteries

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Energy Material Advances 2021年第1期2021卷 98-119页

作者： Natalia Voronina seung-taek Myung Hybrid Materials Research Center Department of Nano Technology and Advanced Materials EngineeringSejong Battery InstituteSejong UniversitySeoul 05006Republic of Korea

The development of sodium-ion batteries(SIBs),which are promising alternatives to lithium-ion batteries(LIBs),offers new opportunities to address the depletion of Li and Co resources;however,their implementation is hindered by their relatively low capacities and moderate operation voltages and resulting low energy *** overcome these limitations,considerable attention has been focused on anionic redox reactions,which proceed at high voltages with extra *** manuscript covers the origin and recent development of anionic redox electrode materials for SIBs,including state-of-the-art P2-and O3-type layered *** sequentially analyze the anion activity–structure–performance relationship in electrode ***,we discuss remaining challenges and suggest new strategies for future research in anion-redox cathode materials for SIBs.

关键词： materials. electrode overcome

Novel N-doped multichannel carbon nanofiber architecture with porous CoS nanoprisms for high-performance potassium-ion batteries

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Rare Metals 2024年第3期43卷 971-983页

作者： Jae Bong lim seung-Keun Park Department of Advanced Materials Engineering Chung-Ang UniversityGyeonggi-do17546Republic of Korea Department of Intelligence Energy and Industry Chung-Ang UniversitySeoul06974Republic of Korea Western Seoul Center Korea Basic Science InstituteSeoul03759Republic of Korea

Potassium-ion batteries(PIBs)have gained significant attention as an alternative to lithium-ion batteries(LIBs)due to the abundance of potassium(K)and low ***,the difficulty in finding appropriate electrode materials that can efficiently store the larger K ions has hindered their practical ***,we report a novel anode material,N-doped multichannel carbon nanofibers embedded with porous CoS nanoprisms(CSP@NMCNF),for high-performance *** CSP@NMCNF was synthesized using a two-step strategy comprising of the electrospinning of Co acetate hydroxide nanoprism/binary polymer blend and a subsequent heat *** porous CoS nanoprisms with an anisotropic morphology were well aligned along the length axis of the N-doped multichannel carbon nanofibers,thus ensuring their structural stability during the repeated charge-discharge *** addition,numerous pores facilitated the transport of electrons and ***,the CSP@NMCNF anode exhibited excellent electrochemical performance,delivering a high specific capacity of 368 mAh·g^(-1)at 0.5 A·g^(-1)after 200 cycles and excellent rate capability(232 mAh·g^(-1)at 2.0 A·g^(-1)).

关键词： K-ion batteries Cobalt sulfide Multichannel structured composite Electrospinning Nanoprism Porous structure

Upgrading and upstaging of low-risk prostate cancer among Korean patients： a multicenter study

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Asian Journal of Andrology 2015年第5期17卷 811-814,I0009页

作者： Insang Hwang Donghoon lim Young Beom Jeong seung Chol Park Jun Hwa Noh Dong Deuk Kwon taek Won Kang Department of Urology Chonnam National University Medical School Gwangju Korea Department of Urology Chosun University Medical School Gwangju Korea Department of Urology Chonbuk National University Medical School Jeonju Korea Department of Urology Wonkwang University School of Medicine Iksan Korea Department of Urology Kwangju Christian Hospital Gwangju Korea

Only 54% of prostate cancer cases in Korea are localized compared with 82% of cases in the US. Furthermore, half of Korean patients are upgraded after radical prostatectomy （41.6%-50.6%）. We investigated the risk factors for upgrading and/or upstaging of low-risk prostate cancer after radical prostatectomy. We retrospectively reviewed the medical records of 1159 patients who underwent radical prostatectomy at five hospitals in Honam Province. Preoperative data on standard clinicopathological parameters were collected. The radical prostatectomy specimens were graded and staged and we defined a ＂worsening prognosis＂ as a Gleason score ≥ 7 or upstaging to ≥ pT3. Multivariate logistic regression models were used to assess factors associated with postoperative pathological upstaging. Among the 1159 patients, 324 were classified into the clinically low-risk group, and 154 （47.5%） patients were either upgraded or upstaged. The multivariable analysis revealed that the preoperative serum prostate-specific antigen level （odds ratio [OR], 1.131; 95% confidence interval [CI], 1.007-1.271; P = 0.037）, percent positive biopsy core （OR： 1.018; 95% CI： 1.002-1.035; P = 0.032）, and small prostate volume （≤30 ml）（OR： 2.280; 95% CI： 1.351-3.848; P = 0.002） were predictive of a worsening prognosis. Overall, 47.5% of patients with low-risk disease were upstaged postoperatively. The current risk stratification criteria may be too relaxed for our study cohort.

关键词： prostate cancer prostatectomy risk factors

A Comparison of GPS- and NWP-derived PW Data over the Korean Peninsula

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Advances in Atmospheric Sciences 2010年第4期27卷 871-882页

作者： Ha-taek KWON Eui-Hyun JUNG Gyu-Ho lim School of Earth and Environmental Sciences Seoul National University Seoul 151-172 Korea

Precipitable Water （PW） derived from Global Positioning System （GPS） measurements and numerical weather prediction （NWP） model analysis data were compared to further evaluate the effcacy of applying GPS-derived PW to the NWP model. The spatial and temporal variations of GPS-derived PW during a rainfall event were also examined. GPS-derived PW measurements show good agreement with the behavior of water vapor at a high spatial resolution during the analysis period. Temporal anomalies of GPS-derived PW moving along with the front are successfully detected by the GPS array. Large positive anomalies of GPS-derived PW are indicated immediately before a rainfall event, and the intensity of these positive anomalies do not seem to decrease significantly as the precipitation system passes. These results indicate that the Korean GPS network may have great potential as a PW sensor over the Korean Peninsula. In contrast with GPS-derived PW, NWP-derived PW shows negative biases. These biases appear to stem mainly from the differences between modeled and actual GPS site elevations, as GPS sites were generally located at elevations lower than those employed by the NWP model. However, there still exists a discernable dry bias after a PW correction is applied to NWP-derived PW. GPS-derived PW better reflects the spatial and temporal moisture variations of precipitation systems, as compared to NWP-derived PW. These results provide entirely new information for improving the regional NWP system, since GPS-derived PW produced with data from the Korean GPS network may be incorporated into the NWP model to improve rainfall forecasts.

关键词： GPS precipitable water numerical weather prediction model dry bias

Discreteness of Flux Groups

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Acta Mathematica Sinica,English Series 2006年第1期22卷 115-122页

作者： Yong seung CHO Myung Im lim Department of Mathematics Ewha Women's-University Seoul 120-750 Korea

Let （M, ω） be a closed symplectic 2n-dimensional manifold. Donaldson in his paper showed that there exist 2m-dimensional symplectie submanifolds （V^2m,ω） of （M,ω）, 1 ≤m ≤ n - 1, with （m - 1）-equivalent inclusions. On the basis of this fact we obtain isomorphic relations between kernel of Lefschetz map of M and kernels of Lefschetz maps of Donaldson submanifolds V^2m, 2 ≤ m ≤ n - 1. Then, using this relation, we show that the flux group of M is discrete if the action of π1 （M） on π2（M） is trivial and there exists a retraction r ： M→ V, where V is a 4-dimensional Donaldson submanifold. And, in the symplectically aspherical case, we investigate the flux groups of the manifolds.

关键词： Symplectic diffeomorphisms Flux Symplectically aspherical manifold Donaldson submanifold

Impact loads generated by tandem cavitation bubble on solid wall

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Journal of Hydrodynamics 2022年第3期34卷 467-482页

作者： Nyo Me Thet Naing Jaehyun Park seung-Ho Hyun Rho-taek Jung School of Naval Architecture and Ocean Engineering University of UlsanUlsanKorea School of Electrical Engineering University of UlsanUlsanKorea Foundation for Industry Cooperation University of UlsanUlsanKorea

Experiments on two cavitation bubbles,which are generated at the same instant,with three different sizes near solid wall are conducted and their impulses on the boundary are registered by polyvinylidene fluoride(PVDF)*** to being near the boundary,bubble interactions and deformed features are in contrast with those in infinite fluid *** this paper,five morphologies of bubble deformation during growth and collapse phases are observed by high-speed *** profiles are strongly influenced by inter-bubble distance(η),stand-off distance from boundary(γ),and bubble size *** of photographs coupled with sensor measurements enabled qualitative investigation of two bubble interactions on the *** sensor data acquisition,it is confirmed that lower bigger bubble with upper smaller bubble configuration produces highest impulses on the boundary compared with other vertical arrangements of the tandem cavitation bubble employed in this study.

关键词： Two bubbles spark-generated bubble impulse polyvinylidene fluoride(PVDF)

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

Ultimate strength of single shear bolted connections with cold-formed ferritic stainless steel

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第2期14卷 120-136页

作者： Jin-seong lim Tae-soo KIM seung-hun KIM Department of Architectural Engineering Hanbat National UniversityDaejeon 305-719Korea

This paper is focused on the structural behavior of the single shear bolted connections with thin-walled ferritic stainless *** purpose of this study is to investigate the ultimate behaviors,such as ultimate strength and fracture mode of the single shear bolted connections of thin-walled ferritic stainless steel(low cost steel) rather than austenitic stainless steel(high cost steel).Bolt arrangement and end distance parallel to the direction of applied load are considered as main variables of the test specimens for bolted *** have a constant dimension of edge distance perpendicular to the loading direction,bolt diameter,pitch,and gauge.A monotonic tensile test for specimens has been carried out and some bolted connections with long end distance showed curling(out of plane deformation) occurrence which led to strength *** ultimate behaviors such as fracture mode,ultimate strength are compared with those predicted by current design ***,conditions of curling occurrence and the strength reduction due to curling are investigated and modified strength equations are suggested considering the curling effect.

关键词： Cold-formed ferritic stainless steel Bolted connection Bolt arrangement End distance Curling Strength reduction

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