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Regulating interfacial stability of SiO_(x) anode with fluoride-abundant solid–electrolyte interphase by fluorine-functionalized additive

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Rare Metals 2024年第2期43卷 671-681页

作者： Subin lee Taeeun Yim Advanced Batteries Laboratory Department of ChemistryIncheon National UniversityIncheon22012Republic of Korea Research Institute of Basic Sciences College of Natural ScienceIncheon National UniversityIncheon22012Republic of Korea

Silicon oxide(SiO_(x))has received remarkable attention as a next-generation battery material;however,the sudden decrease in the cycling retention constitutes a significant challenge in facilitating its ***(2,2,2-trifluoroethyl)phosphite(TTFP),which can control parasitic reactions such as the pulverization of SiO_(x)anode materials and electrolyte decomposition,has been proposed to improve the lifespan of the *** electrochemical reduction of TTFP results in solid-electrolyte interphase(SEI)layers that are mainly composed of LiF,which occur at a higher potential than the working potential of the SiO_(x)anode and carbonate-based *** electrolyte with TTFP exhibited a substantial improvement in cycling retention after 100 cycles,whereas the standard electrolyte showed acutely decreased *** thickness of the SiO_(x)anode with TTFP also changed only slightly without any considerable delamination spots,whereas the SiO_(x)anode without TTFP was prominently deformed by an enormous volume expansion with several internal *** cycled SiO_(x)anode with TTFP exhibited less increase in resistance after cycling than that in the absence of TTFP,in addition to fewer decomposition adducts in corresponding X-ray photoelectron spectroscopy(XPS)analyses between the cycled SiO_(x)*** results demonstrate that TTFP formed SEI layers at the SiO_(x)interface,which substantially reduced the pulverization of the SiO_(x)anode materials;in addition,electrolyte decomposition at the interface decreased,which led to improved cycling retention.

关键词： Lithium-ion batteries(LIBs) Silicon oxide anode Electrolyte Additive Solid-electrolyte interphases(SEI) Tris(2,2,2-trifluoroethyl)phosphite

A Favré averaged transition prediction model for hypersonic flows

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Science China(Technological Sciences) 2010年第8期53卷 2049-2056页

作者： lee ChunHian School of Aeronautical Sciences and Engineering Beijing University of Aeronautics and Astronautics

Transition prediction is crucial for aerothermodynamic and thermal protection system design of hypersonic *** compressible form of laminar kinetic energy equation is derived based on Favréaverage formality in the present paper.A closure of the equation is deduced and simplified under certain hypotheses and scaling analysis.A laminar-to-turbulent transition prediction procedure is proposed for high Mach number flows based on the modeled Favré-averaged laminar kinetic energy equation,in conjunction with the Favré-averaged Navier-Stokes *** proposed model,with and without associated explicit compressibility terms,is then applied to simulate flows over flared-cones with a free-stream Mach number of 5.91,and the onset locations of the boundary layer transition under different wall conditions are *** computed onset locations are compared with those obtained by the model based on a compressibility correction deduced from the reference-temperature concept,together with experimental *** is revealed that the present model gives a more favorable transition prediction for hypersonic flows.

关键词： transition prediction laminar fluctuation hypersonic compressibility

Effects of surface roughness on bending properties of rolled AZ31 alloy

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Journal of Magnesium and Alloys 2023年第4期11卷 1224-1235页

作者： Gyo Myeong lee Jong Un lee Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

This study investigated the effects of mechanical-polishing-induced surface roughness and the direction of polishing lines on the bending properties of a rolled AZ31 *** this end,three-point bending tests were performed on one sample without polishing lines(SS sample)and two samples with polishing lines—one in which the polishing lines were parallel to the rolling direction(RS-RD sample)and the other in which they were parallel to the transverse direction(RS-TD sample).In all three samples,macrocracks were formed in the width direction on the outer surface,where tensile stress was predominantly generated in the longitudinal ***,the macrocracks formed in the SS sample were curved because of the merging of uniformly formed fine microcracks,whereas those formed in the RS-TD sample were linear owing to the formation of relatively coarse microcracks along the polishing *** bendability of the samples was in the order of SS>RS-RD>RS-TD,and their limiting bending depths were 4.8,4.6,and 4.4 mm,*** the presence of mechanical-polishing-induced surface roughness,polishing lines perpendicular to the direction of the major stress(i.e.,tensile stress along the longitudinal direction)resulted in a greater degree of stress concentration on the outer surface of the bending *** higher stress concentration promoted the formation of undesirable{10–11}contraction and{10–11}–{10–12}double twins—which typically act as crack initiation sites—and thereby facilitated crack generation and ***,the surface roughness caused premature fracture during bending deformation,which,in turn,caused deterioration of the bendability of the rolled Mg alloy.

关键词： AZ31 alloy Bending Surface roughness Stress concentration Crack

Experimental Investigation and Numerical Analysis to Develop Low-Energy Large-Midwater Trawls

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China Ocean Engineering 2017年第6期31卷 700-708页

作者： Jihoon lee Taeho KIM Chun-Woo lee Subong PARK Division of Marine Technology Chonnam National University Yeosu 550-749 Korea Division of Marine Production System Management Pukyong National University Busan 608-737 Korea Department of Fisheries Physics Pukyong National University Busan 608-737 Korea

Fuel consumption in fisheries is a primary concern because of its effects on the environment and the costs incurred by fishermen. Many studies have been conducted to reduce the fuel consumption in fishing operations. Fuel consumption due to fishing gear during a fishing operation is generally related to the hydrodynamic resistance on the gear. This means that fuel consumption is proportional to the drag created by the towing speed. Based on numerical methods, this study suggests a new approach to reduce fuel consumption in fisheries. The results of the simulation are in good agreement with those of model experiments. The total as well as partial resistance forces on the gear are calculated by simulation. The simulation results suggest improved materials and gear structure for reducing the hydrodynamic forces on the gear while maintaining gear performance. The method for assessing the gear performance involves measuring the height and width of the net mouth. Furthermore, this study investigates the efficiency of a low-energy trawl from an economic point of view. The findings of this study will be useful in reducing greenhouse gas （GHG） emissions in fishing operations, and thereby contribute toward lowering fishing costs by saving fuel.

关键词： low-energy fishing gear numerical methods greenhouse gasesemission hydrodynamic resistance fuelconsumption

A study on neural mechanism of face processing based on fMRI

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Progress in Natural Science:Materials International 2008年第2期18卷 201-207页

作者： Kang lee Canada Institute of Child Study University of Toronto

Recently,there were debates about the specificity of lateral middle fusiform in face processing. The debates focused on whether these areas were specialized in face processing or involved in processing of visual expertise and categorization at individual level. The present study aims to investigate the neural mechanism of face processing,using Chinese characters as comparison stimuli. Chinese characters are greatly similar to faces on a variety of dimensions,among which the most significant one is that both faces and Chinese characters not only are extremely familiar to literate Chinese adults but also are processed at individual level. In the present study,faces and Chinese characters activated bilateral middle fusiform with great correlation. Greater activities were observed in the right fusiform face area (FFA) for faces than for Chinese characters. These results demonstrate that FFA is specialized in face processing per se rather than the processing of visual expertise and categorization at individual level.

关键词： Face processing Chinese characters Fusiform gyrus fMRI

Impacts of optimization strategies on performance,power/energy consumption of a GPU based parallel reduction

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Journal of Central South University 2017年第11期24卷 2624-2637页

作者： Phuong Thi Yen lee Deok-Young lee Jeong-Gun Smart Computing Lab. Department of Computer EngineeringHallym UniversityChuncheon 24252Korea College of General Education Hallym UniversityChuncheon 24252Korea

In the era of modern high performance computing, GPUs have been considered an excellent accelerator for general purpose data-intensive parallel applications. To achieve application speedup from GPUs, many of performance-oriented optimization techniques have been proposed. However, in order to satisfy the recent trend of power and energy consumptions, power/energy-aware optimization of GPUs needs to be investigated with detailed analysis in addition to the performance-oriented optimization. In this work, in order to explore the impact of various optimization strategies on GPU performance, power and energy consumptions, we evaluate performance and power/energy consumption of a well-known application running on different commercial GPU devices with the different optimization strategies. In particular, in order to see the more generalized performance and power consumption patterns of GPU based accelerations, our evaluations are performed with three different Nvdia GPU generations(Fermi, Kepler and Maxwell architectures), various core clock frequencies and memory clock frequencies. We analyze how a GPU kernel execution is affected by optimization and what GPU architectural factors have much impact on its performance and power/energy consumption. This paper also categorizes which optimization technique primarily improves which metric(i.e., performance, power or energy efficiency). Furthermore, voltage frequency scaling(VFS) is also applied to examine the effect of changing a clock frequency on these metrics. In general, our work shows that effective GPU optimization strategies can improve the application performance significantly without increasing power and energy consumption.

关键词： parallel reduction GPU code optimization power energy voltage frequency scaling

Characterization of the three-dimensional supersonic flow for the MHD generator

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Science China(Physics,Mechanics & Astronomy) 2009年第4期52卷 534-545页

作者： lee ChunHian National Laboratory for Computational Fluid Dynamics Beihang University

A numerical procedure based on a five-wave MHD model associated with non-ideal,low magnetic Reynolds number MHD flows was developed in the present study for analyzing the flow fields in the MHD generator of a MHD bypass scramjet. The numerical procedure is composed of an entropy conditioned scheme for solving the non-homogeneous Navier-Stokes equations,in conjunction with an SOR method for solving the elliptic equation governing the electrical potential. It was found that a separation would take place near the downstream edge of the second electrode,where the local adverse pressure gradient is large,and the core of the flow field is characterized as a 2-D flow due to the Hartmann effects along the direction of the magnetic field. The electric current lines would be increasingly distorted as the magnetic interactive parameter increases,and even induce an eddy current. Induced eddy current was also found in the different cross-sections along the axial direction,all of these would definitely deteriorate the performance of the MHD generator. The cross-sectional M-shape velocity profile found along the axial direction between the insulating walls is responsible for the formation of the vortex flow at the corner of the insulator cross-section,which,in turn,induces the corner eddy current at the corner. A numerical parametric study was also performed,and the computed performance parameters for the MHD generator suggest that,in order to enhance the performance of MHD generator,the magnetic interaction parameter should be elevated.

关键词： MHD generator entropy conditioned scheme SOR numerical simulation

A numerical study of turbulent combustion characteristics in a combustion chamber of a scramjet engine

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Science China(Technological Sciences) 2010年第8期53卷 2111-2121页

作者： lee ChunHian School of Aeronautical Sciences and Engineering Beihang University

3D numerical simulation of flow fields in a combustion chamber of a scramjet engine using an SST turbulence model with an explicit compressibility correction was performed and the results were compared to the experimental *** characteristics of the turbulent combustion flow fields were analyzed via the numerical results and *** order to identify the mechanisms of turbulent combustion in supersonic flows,the evolutions of governing dimensionless parameters in the flow fields were investigated based on the theory of combustion and the available numerical *** was found that the supersonic combustion takes place in the region of fully developed turbulence and that the strongest effects of turbulence and combustion processes appear in the vicinity of the *** unsteady effects and the local flame extinction phenomenon induced by turbulent flows were found to be negligibly small,and the steady flamelet approximation will hold for practical applications.

关键词： scramjet turbulent combustion flamelet approximation numerical simulation

A Fast Quantitative Analysis and Performance Estimation Method of SoC Bus Architectures

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Chinese Journal of Electronics 2014年第4期23卷 682-687页

作者： Jaesung lee Department of Electronic Engineering Korea National University of Transportation

Various multi-layered bus architectures are now being used in the So C industry. Reckless use of bus layers may result in low utilization of communication resource and waste silicon area. This paper introduces a quantitative analysis at the initial stage of So C *** time complexity is examined and it is found that their scale is the order of n to the power of n, or combinatorial,and thus the problem is NP-complete. The paper proposes some heuristic methods through in-depth investigation and applies them to each step of the exploration to reduce the time complexity. The exploration processes and the proposed methods are implemented as a software program and several experiments are performed. From the results, the performance of SNP turns out to be significantly enhanced and achieves 25% enhancement in comparison with a defacto standard bus, AXI. For time complexity, the reduction ratio goes down to 3.7 × 10-6.

关键词： System-on-chip On-chip bus Design automation Multi-layered architecture