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Bimetallic Ni-Co MOF@PAN modified electrospun separator enhances high-performance lithium-sulfur batteries

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journal of Energy Chemistry 2023年第7期82卷 484-496,I0010页

作者： Xiaolong Leng Jie Zeng Mingdai Yang Changping Li S.V.Prabhakar Vattikuti Jielin Chen Shuang Li Jaesool Shim Tong Guo tae jo ko School of Mechanical Engineering Yeungnam UniversityGyeongsangbuk-do 38541Republic of Korea College of Mechanical and Electrical Engineering Hunan University of Science and TechnologyXiangtan 411201HunanChina Key Laboratory for Soft Chemistry and Functional Materials of Ministry of Education Nanjing University of Science and TechnologyNanjing 210094JiangsuChina

Lithium-sulfur(Li-S)batteries with high energy density are considered promising energy storage devices for the next ***,the shuttle effect and the passive layer between the separator and the electrodes still seriously affect the cycle stability and ***,a bimetallic Ni-Co metal-organic framework(MOF)with adsorption and catalytic synergism for polysulfides was successfully synthesized as an electrospinning separator sandwich for Li-S *** porous Ni-Co MOF coatings into the separator provides more adsorption catalytic sites for polysulfides,prevents their diffusion to the anode,and enhances sulfur ***,the improved Li-S batteries with a Ni-Co MOF@PAN(NCMP)electrospun separator delivered excellent rate performance and outstanding cycle stability,yielding an ultra-high initial capacity of 1560 mA h g^(-1)at 0.1 ***,remarkable Li-S battery performance with a discharge capacity of 794 mA h g^(-1)(84.1%capacity retention)was obtained after500 cycles,while delivering a low capacity decay rate of 0.032%during long-term cycling(up to 500cycles)at 1 ***,even at the current density of 2 C,the capacity attenuation rate of 2000 cycles is only 0.034%per *** addition,compared with the Celgard separator,the NCMP separator also had high thermal stability(keeping the separator outline at 200℃)that ensured battery safety and excellent electrolyte wettability(73%porosity and 535%electrolyte absorption)and significantly enhanced the ionic conductivity and Li^(+) transfer number,and protected the surface integrity of the anode.

关键词： Li-S batteries Ni-Co MOF Adsorption catalysis Synergistic effect

Influence of overhanging tool length and vibrator material on electromechanical impedance and amplitude prediction in ultrasonic spindle vibrator

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journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第4期25卷 292-310页

作者： Rendi KURNIAWAN Moran XU Min Ki CHOO Shuo CHEN Yein KWAK' Jielin CHEN Saood ALI Hanwei TENG Pil Wan HAN Gi Soo KIM tae jo ko Precision Machining Laboratory Department of Mechanical Engineering Yeungnam UniversityGyeongsansiGyeongbuk-doRepublic of Korea korea Electrotechnology Research Institute(KERI) ChangwonsiGyeongsangnam-doRepublic of Korea KASWIN Co. LtdChangwon-siGyeongsangnamdoRepublic of Korea

This study presents the development of an ultrasonic transducer with a radius horn for an ultrasonic milling spindle(UMS)*** ultrasonic transducer was intended to have a working frequency of approximately 30 *** different materials were considered in the study:stainless steel(SS 316L)and titanium alloy(Ti-6Al-4V).Titanium alloy gave a higher resonance frequency(33 kHz)than stainless steel(30 kHz)under the same preload compression *** electromechanical impedance simulation was carried out to predict the impedance resonance frequency for both materials,and the effect of the overhanging toolbar was *** to the electromechanical impedance simulation,the overhanging toolbar length affected the resonance frequency,and the error was less than 3%.Harmonic analysis confirmed that the damping ratio helps determine the resonance ***,damping ratios of 0.015-0.020 and 0.005-0.020 were selected for stainless steel and titanium alloy,respectively,with an error of less than 1.5%.Experimental machining was also performed to assess the feasibility of ultrasonic-assisted milling;the result was a lesser cutting force and better surface topography of Al 6061.

关键词： Ultrasonic spindle Ultrasonic vibration assisted-milling(UVAM) 1-degree of freedom(DOF) Frequency Amplitude Milling

Cutting force signal pattern recognition using hybrid neural network in end milling

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中国有色金属学会会刊：英文版 2009年第B9期19卷 209-214页

作者： Song-tae SEONG ko-tae jo Young-Moon LEE Research and Development Department Gyeongbuk Hybrid Technology Institute School of Mechanical Engineering Yeongnam University School of Mechanical Engineering Kyungpo ok National University

Under certain cutting conditions in end milling, the signs of cutting forces change from positive to negative during a revolution of the tool. The change of force direction causes the cutting dynamics to be unstable which results in chatter vibration. Therefore, cutting force signal monitoring and classification are needed to determine the optimal cutting conditions and to improve the efficiency of cut. Artificial neural networks are powerful tools for solving highly complex and nonlinear problems. It can be divided into supervised and unsupervised learning machines based on the availability of a teacher. Hybrid neural network was introduced with both of functions of multilayer perceptron (MLP) trained with the back-propagation algorithm for monitoring and detecting abnormal state, and self organizing feature map (SOFM) for treating huge datum such as image processing and pattern recognition, for predicting and classifying cutting force signal patterns simultaneously. The validity of the results is verified with cutting experiments and simulation tests.

关键词：切削力信号混合神经网络模式识别铣床人工神经网络切削条件信号监测监督学习

Homeostasis and regulation of autoreactive B cells

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Cellular & Molecular Immunology 2020年第6期17卷 561-569页

作者： Sujin Lee Yeunjung ko tae Jin Kim Department of Immunology Sungkyunkwan University School of MedicineSuwon 16419Republic of Korea

In contrast to the previous belief that autoreactive B cells are eliminated from the normal repertoire of B cells,many autoreactive B cells actually escape clonal deletion and develop into mature B *** autoreactive B cells in healthy individuals perform some beneficial functions in the host and are homeostatically regulated by regulatory T and B cells or other mechanisms to prevent autoimmune *** B-1 cells constitutively produce polyreactive natural antibodies for tissue ***,autoreactive follicular B cells were reported to participate actively in the germinal center ***,the selection and usefulness of autoreactive marginal zone(MZ)B cells found in autoimmune diseases are not well understood,although the repertoire of MZ B-cell receptors(BCRs)is presumed to be biased to detect bacterial *** this review,we discuss the autoreactive B-cell populations among all three major B-cell subsets and their regulation in immune responses and diseases.

关键词： B-cell autoreactivity polyreactivity autoreactive antibody B-cell receptor B-1 lymphocyte autoreactive germinal center autoreactive marginal zone B cell

Prediction of characteristic blast-induced vibration frequency during underground excavation by using wavelet transform

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Frontiers of Structural and Civil Engineering 2022年第8期16卷 1029-1039页

作者： tae Un PAK Guk Rae jo Un Chol HAN Faculty of Mining Engineering Kim Chaek University of TechnologyPyongyang 999093Democratic People’s Republic of Korea School of Science and Engineering Kim Chaek University of TechnologyPyongyang 999093Democratic People’s Republic of Korea

Blast-induced vibration produces a very complex signal,and it is very important to work out environmental problems induced by *** this study,blasting vibration signals were measured during underground excavation in carbonaceous shale by using vibration pickup CB-30 and FFT analyzer ***,wavelet analysis on the measured results was carried out to identify frequency bands reflecting changes of blasting vibration parameters such as vibration velocity and energy in different frequency *** characteristics are then discussed in view of blast source distance and charge weight per *** analysis of results,it can be found that peak velocity and energy of blasting vibration in frequency band of 62.5–125 Hz were larger than ones in other bands,indicating the similarity to characteristics in the distribution band(31–130 Hz)of main vibration *** frequency bands were affected by blasting source distance,and the frequency band of 0–62.5 Hz reflected the change of charge weight per *** presenting a simplified method to predict main vibration frequency,this research may provide significant reference for future blasting engineering.

关键词： wavelet analysis blast-induced vibration frequency characteristics underground excavation

Development of single-action,two-step clinching system using finite element analysis

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中国有色金属学会会刊：英文版 2009年第B9期19卷 266-270页

作者： Seong-Wook LEE tae-Hyung KIM Geun-jo HAN Power & Industrial Systems R&D Center Hyosung Corporation Department of Mechanical Engineering Department of Mechanical Engineering Dong-A University

Traditional manufacturing processes for bending and combining the upper and lower heat insulation plates for a car catalytic converter need two kinds of bending dies. This study was carried out to develop a single-action, two-step clinching system for clinching heat insulation plates. To design the operating mechanism for this clinching system, finite element analysis was used to estimate the bending load needed and to predict the bent shape of the heat insulation plate. Then a recovery and cushioning system was designed for the bending die. It is expected that this new process will improve the manufacturing quality of heat insulation plates and will reduce manufacturing cost. And a higher value-added technique for mold and pressing systems was introduced.

关键词：缓冲系统有限元分析开发汽车催化转化器单动模具技术隔热板板弯曲

Effect of open-field experimental warming on the leaf phenology of oriental oak (Quercus variabilis) seedlings

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journal of Plant Ecology 2014年第6期7卷 559-566页

作者： Saerom Han Haegeun Chung Nam Jin Noh Sun Jeoung Lee Wooyong jo tae Kyung Yoon koong Yi Chan-woo Park Suin ko Yowhan Son Department of Environmental Science and Ecological Engineering Graduate SchoolKorea UniversitySeoul 136-713Korea Department of Environmental Engineering Konkuk UniversitySeoul 143-701Korea River Basin Research Center Gifu UniversityGifu 501-1193Japan Forest and Climate Change Center Korea Forest Research InstituteSeoul 130-712Korea Hanlim Patent and Law Office Seoul 152-050Korea Forest Soil and Water Conservation Division Korea Forest Research InstituteSeoul 130-712Korea Environmental Policy Research Group Korea Environment InstituteSeoul 122-706Korea

Aims An open-field warming experiment enables us to test the effects of projected temperature increase on change in plant phenology with fewer confounding factors and to study phenological response to temperature ranges beyond natural *** study aims to(i)examine the effect of temperature increase on leaf unfold-ing and senescence of oriental oak(Quercus variabilis Blume)under experimental warming and(ii)measure temperature-related parameters used in estimating phenological response to tempera-ture *** Using an open-field warming system with infrared heaters,we increased the air temperature by~3℃ in the warmed plots compared with that of the control plots consistently for 2 *** unfolding and senescence dates of *** seedlings were recorded and temperature-related phenological parameters were *** Findings The timing of leaf unfolding was advanced by 3-8 days(1.1-3.0 days/℃)and the date of leaf senescence was delayed by 14-19 days(5.0-7.3 days/℃)under elevated air ***,the cumulative degree days(CDD)of leaf unfolding were not significantly changed by experimental warming,which suggest the applicability of a constant CDD value to estimate the change in spring leaf phe-nology under 3℃ *** ranges of advancement and temperature sensitivity in spring phenology and delayed autumn phe-nology and proposed temperature parameters from this study might be applied to predict future phenological change.

关键词： climate change cumulative degree days experimental warming leaf senescence leaf unfolding

Development of a hybrid scaffold and a bioreactor for cartilage regeneration

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Chinese Science Bulletin 2009年第19期54卷 3608-3612页

作者： LEE Seung-Jae LEE In Hwan PARK Jeong Hun GWAK So-Jung RHIE jong-Won CHO Dong-Woo ko tae jo KIM Dong Sung BK21 Mechatronics Group at Chungnam National University School of Mechanical Engineering Chungbuk National University DDS Research Lab. CKD Research Institute CKD Pharmaceutical Corp. Department of Plastic Surgery College of Medicine The Catholic University of Korea Department of Mechanical Engineering Pohang University of Science and Technology School of Mechanical Engineering Yeungnam University School of Mechanical Engineering Chung-Ang University

We developed a hybrid scaffold and a bioreactor for cartilage regeneration. The hybrid scaffold was developed as combination of two components: a biodegradable framework and hydrogel-containing chondrocytes. We performed the MTT cell proliferation assay to compare the proliferation and viability of chondrocytes on three types of scaffolds: an alginate gel, the hybrid scaffold, and an alginate sponge. Cells were encapsulated in 2% agarose gel. The bioreactor consisted of a circulation system and a compression system. We performed dynamic cell culture on these agarose gels in the bioreactor for 3 days.

关键词： MTT 生物分解凝解胶研究

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