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Haze formation in China: Importance of secondary aerosol

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Journal of Environmental sciences 2015年第7期27卷 261-262页

作者： Alex k.Y.lee Department of Chemistry University of Toronto

Air pollution is the world＇s largest single environmental hazard that causes more than a few million premature deaths in 2012（World Health Organization,2014）,particularly in developing countries with rapid industrialization and *** economic growth of China in the last three decades has resulted in serious air pollution problems on both local and regional scales.

关键词： Haze formation in China Importance of secondary aerosol PM

supramolecular Polymer Intertwined Free-standing Bifunctional Membrane Catalysts for All-Temperature Flexible Zn-Air Batteries

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Nano-Micro Letters 2022年第11期14卷 341-360页

作者： Nayantara k.Wagh sambhaji s.shinde Chi Ho lee sung-Hae kim Dong-Hyung kim Han-Don Um sang Uck lee Jung-Ho lee Department of Materials science and Chemical Engineering Hanyang UniversityAnsanRepublic of Korea Department of Applied Chemistry Center for Bionano Intelligence Education and ResearchHanyang UniversityAnsanRepublic of Korea Department of Chemical Engineering Kangwon National UniversityChuncheonGangwon 24341Republic of Korea

Rational construction of flexible free-standing electrocatalysts featuring long-lasting durability,high efficiency,and wide temperature tolerance under harsh practical operations are fundamentally significant for commercial zinc-air ***,3D flexible free-standing bifunctional membrane electrocatalysts composed of covalently cross-linked supramolecular polymer networks with nitrogen-deficient carbon nitride nanotubes are fabricated(referred to as PEMAC@NDCN)by a facile self-templated ***@NDCN demonstrates the lowest reversible oxygen bifunctional activity of 0.61 V with exceptional long-lasting durability,which outperforms those of commercial Pt/C and RuO_(2).Theoretical calculations and control experi-ments reveal the boosted electron transfer,electrolyte mass/ion transports,and abundant active surface site ***,the constructed alkaline Zn-air battery with PEMAC@NDCN air-cathode reveals superb power density,capacity,and discharge-charge cycling stability(over 2160 cycles)compared to the reference Pt/C+RuO_(2).solid-state Zn-air batteries enable a high power density of 211 mW cm^(−2),energy density of 1056 Wh kg^(−1),stable charge-discharge cycling of 2580 cycles for 50 mA cm^(−2),and wide temperature tolerance from−40 to 70℃with retention of 86%capacity compared to room-temperature counterparts,illustrating prospects over harsh operations.

关键词： Flexible free-standing membrane electrocatalysts supramolecular polymer Alkaline and flexible solid-state Zn-air batteries All-temperature operations High capacity and energy density

Generalized polynomial chaos expansion by reanalysis using static condensation based on substructuring

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 819-836页

作者： D.lee s.CHANG J.lee Department of Automotive Engineering Hanyang UniversitySeoul 04763Republic of Korea school of Mechanical Engineering Chungnam National UniversityDaejeon 34134Republic of Korea Department of Mechanical Robotics and Energy EngineeringDongguk UniversitySeoul 04620Republic of Korea

This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random *** method consists of a generalized polynomial chaos expansion(GPCE)for statistical moment and reliability analyses associated with the stochastic output and a static reanalysis method to generate the input-output data *** the reanalysis,we employ substructuring for a structure to isolate its local regions that vary due to random *** allows for avoiding repeated computations of invariant substructures while generating the input-output data *** substructuring with static condensation further improves the computational efficiency of the reanalysis without losing ***,the GPCE with the static reanalysis method can achieve significant computational saving,thus mitigating the curse of dimensionality to some degree for UQ under high-dimensional *** numerical results obtained from a simple structure indicate that the proposed method for UQ produces accurate solutions more efficiently than the GPCE using full finite element analyses(FEAs).We also demonstrate the efficiency and scalability of the proposed method by executing UQ for a large-scale wing-box structure under ten-dimensional(all-dependent)random inputs.

关键词： forward uncertainty quantification(UQ) generalized polynomial chaos expansion(GPCE) static reanalysis method static condensation substructuring

Implementing the Node Based smoothed Finite Element Method as User Element in Abaqus for Linear and Nonlinear Elasticity

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Computers, Materials & Continua 2019年第8期61卷 481-502页

作者： s.kshrisagar A.Francis J.J.Yee s.Natarajan C.k.lee Integrated Modelling and simulation Lab Department of Mechanical EngineeringIndian Institute of Technology MadrasChennai600036India The Department of Architectural Engineering Dong-A UniversityS04-0302Engineering 237Nakdongdaero 550beon-gilSaha-guBusan49315Korea National Research Center for Disaster-free&safe Ocean City Dong-A UniversityS04-0311-3Engineering 237Nakdong-daero 550beon-gilSaha-guBusan49315Korea

In this paper,the node based smoothed-strain Abaqus user element(UEL)in the framework of finite element method is *** basic idea behind of the node based smoothed finite element(NsFEM)is that finite element cells are divided into subcells and subcells construct the smoothing domain associated with each node of a finite element cell[Liu,Dai and Nguyen-Thoi(2007)].Therefore,the numerical integration is globally performed over smoothing *** is demonstrated that the proposed UEL retains all the advantages of the NsFEM,i.e.,upper bound solution,overly soft stiffness and free from locking in compressible and nearly-incompressible *** this work,the constant strain triangular(CsT)elements are used to construct node based smoothing domains,since any complex two dimensional domains can be discretized using CsT *** additional challenge is successfully addressed in this *** efficacy and robustness of the proposed work is obtained by several benchmark problems in both linear and nonlinear *** developed UEL and the associated files can be downloaded from https://***/nsundar/NsFEM.

关键词： smoothed finite element method(sFEM) node based sFEM(NsFEM) linear and nonlinear elasticity Abaqus UEL(user elements) compressible and nearlyincompressible materials

study of the Interface between steel Insert and Aluminum Casting in EPC

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Journal of Materials science & Technology 2008年第1期24卷 60-64页

作者： k.H.Choe k.s.Park B.H.kang G.s.Cho k.Y.kim k.W.lee M.H.kim A.Ikenaga s.koroyasu Advanced Material Processing Team korea Institute of Industrial Technology IncheonKorea Department of Materials Engineering korea University of Technology and Education ChoongnamKorea Department of Materials science and Engineering Inha University IncheonKorea Department of Metallurgy and Materials science Graduate school of Engineering Osaka Prefecture UniversityOsakaJapan Department of Mechanical and Precision systems Teiko University UtsunomiyaJapan

The effective surface treatment method for steel insert composited with Al base metal by expendable pattern casting （EPC） process and the bonding interface between steel insert and Al base metal were *** was found that Zn plating on steel insert was effective on improving the bonding property between steel insert and Al base metal in EPC *** is thought to promote the formation of diffusion *** almost none content of Zn was observed in the boundary which had been plated on the steel insert.A diffusion layer consisting of Al,si and Fe was formed at the insert/alloy interface and its hardness was higher than the steel insert as matter of course Al base *** layer turned out to be intermetallic compounds of Al-si-Fe *** pouring temperature promoted the diffusion of Fe into Al alloy,so Fe content in intermetallic layers increased at higher pouring *** layer nearest to steel disappeared due to applied pressure.

关键词： Expendable pattern casting Insert casting Intermetallic compound Al-si-Fesystem

Development of an industrial Internet of things suite for smart factory towards re-industrialization

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Advances in Manufacturing 2017年第4期5卷 335-343页

作者： C. k. M. lee s. Z. Zhang k. k. H. Ng Department of Industrial and systems Engineering The Hong Kong Polytechnic University Hong Kong People's Republic of China Department of Information Management Zhejiang University of Finance and Economics Hangzhou 310018Zhejiang People's Republic of China

Re-industrialization, which supports industrial upgrading and transformation, promotes smart production and high value-added manufacturing processes, and helps to create new momentum for the economic. Under the current situation, industrialists encounter several chal- lenges to achieve re-industrialization. Firstly, the cost and technical thresholds for industrialists to leverage emerging technologies are high. secondly, there are huge quantities and numerous types of Internet of things （IoT） devices in smart factories, warehouses and offices. The enormous extents of data exchange and communication, manage- ment, monitoring and control of IoT devices as well as the establishment and maintenance of a reliable cloud platform hinder industrialists to implement an integrated smart production management. Therefore, to achieve re-indus- trialization, an industrial Internet of things （IIoT） suite consisting of a micro-services-based IIoT cloud platform and IIoT-based smart hub is proposed, which helps to materialize re-industrialization and to conduct industrial upgrading and transformation to achieve smart production and high value-added manufacturing processes.

关键词： Industrial Intemet of things (IIoTs) Cloudplatform Micro-services-based Industry 4.0 Reindustrialization

Effect of coating material and lubricant on forming force and surface defects in wire drawing process

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Transactions of Nonferrous Metals society of China 2011年第A1期21卷 104-110页

作者： s.M.BYON s.J.lee D.W.lee Y.H.lee Y.lee Department of Mechanical Engineering Dong-A University Department of Mechanical Engineering Chung-Ang University Wire Rod Research Group POSCO Technical Research Laboratories

A pilot wire drawing machine as well as wire end-pointing roller was developed. Using these machines, a wire drawing test for four different coating materials and two different lubricants was performed as the reduction ratio increased from 10% to 30%. Materials used for a substrate in this study are plain carbon steel （AIs11045） and ultra low carbon bainite steel. To compute the friction coefficient between the coating layer of wire and the surface of die lbr a specific lubricant, a series of finite element analyses were carried out. sEM observations were also conducted to investigate the surface defects of wire deformed. Results show that the behavior of drawing force varies with the lubricant-type at the initial stage of drawing. The powder-typed lubricant with a large particle causes the retardation of lull lubrication on the entire contact surface and the local delamination of coating layer on the wire surface. As the flow stress of a substrate increases, the delamination becomes severe.

关键词： coating lubricant wire drawing delamination

Effect of Applied Pressure on the Joining of Combustion synthesized Ni_3Al Intermetallics with Al Alloy

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Journal of Materials science & Technology 2008年第1期24卷 123-126页

作者： G.s.Cho J.H.Yang k.H.Choe k.W.lee A.Ikenaga Advanced Material Processing Team Korea Institute of Industrial Technology 7-47 Songdo-Dong Yeonsu-Ku Incheon 406-840 Korea Department of Metallurgy and Materials science Graduate School of Engineering Osaka Prefecture University 1-1 Gakuen-Cho Sakai Osaka 599-8531 Japan

We focused on the surface reinforcement of ligth weight casting alloys with Ni-AI intermetallic compounds by in-situ combustion reaction to improve the surface properties of non-ferrous casting *** our previous works,green compact of elemental Ni and Al powders were reacted to form Ni-3Al intermetallic compound by sHs （self-propagating high temperature synthesis） reaction with the heat of molten Al alloy and simultaneously bonded with Al casting *** some defects such as tiny cracks and porosities were remained in the reacted *** we applied pressure to prevent thermal cracks and fill up the pores with liquid Al alloy by squeeze casting *** compressed Al alloy bonded with the Ni-3Al intermetallic compound was sectioned and observed by optical microscopy and scanning electron microscopy （sEM）.The stoichiometric compositions of the intermetallics formed around the bonded interface and in the reacted compact were identified by energy dispersive spectroscopy （EDs） and electron probe micro analysis （EPMA）. si rich layer was formed on the Al alloy side near the bonded interface by the sequential solidification of Al *** porosities observed in the reacted Ni-3Al compact were filled up with the liquid AI *** si particles from the molten Al alloy were detected in the pores of reacted Ni-3Al intermetallic *** Al casting alloy and Ni-3Al intermetallic compound were joined very soundly by applying pressure to the liquid Al alloy.

关键词： Joining Combustion synthesis Ni3AI Intermetallic compound squeeze casting

Effect of Eu^(3+),Bi^(3+),and Li^(+) doping on luminescent property of GdNbO_(4)

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Journal of Rare Earths 2024年第1期42卷 66-75,I0003页

作者： s.W.Wi Y.s.lee Department of Physics and Integrative Institute of Basic sciences Soongsil UniversitySeoul06978Republic of Korea

We investigated the emission properties of Eu^(3+)-doped GdNbO_(4)-based oxide phosphors,aiming at improving the Eu^(3+)emission by codoping of Bi^(3+)and Li^(+).Eu^(3+)singly doped,Eu^(3+)and Bi^(3+)doubly doped,and Eu^(3+),Bi^(3+),and Li^(+)triply doped GdNbO_(4)were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu^(3+)in the singly doped samples are significantly improved by the codoping of Bi^(3+),mainly due to the energy transfer from Bi^(3+)to Eu^(3+).The additional codoping of Li^(+)is found to increase the Eu^(3+)emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu^(3+)in GdNbO_(4)does not change significantly with the codoping of Bi^(3+)and Li^(+).Our results indicate that Li^(+)doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO_(4)phosphors.

关键词： Eu^(3+) GdNbO_(4) Codoping of Li^(+) Photoluminescence sensitizer Rare earths