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Aligned Ion conduction Pathway of Polyrotaxane‑Based Electrolyte with Dispersed Hydrophobic chains for Solid‑State Lithium–Oxygen Batteries

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Nano-Micro Letters 2025年第2期17卷 169-186页

作者： Bitgaram kim Myeong‑chang Sung Gwang‑Hee Lee Byoungjoon hwang Sojung Seo Ji‑Hun Seo Dong‑Wan kim Department of Materials Science and Engineering Korea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea School of civil Environmental and Architectural EngineeringKorea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea Materials Science and chemical Engineering center Institute for Advanced Engineering(IAE)Yongin 17180Republic of Korea

A critical challenge hindering the practical application of lithium–oxygen batteries(LOBs)is the inevitable problems associated with liquid electrolytes,such as evaporation and safety *** study addresses these problems by proposing a modified polyrotaxane(mPR)-based solid polymer electrolyte(SPE)design that simultaneously mitigates solvent-related problems and improves ***-SPE exhibits high ion conductivity(2.8×10^(−3)S cm^(−1)at 25℃)through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain *** this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 *** situ Raman spectroscopy reveals the presence of an LiO_(2)intermediate alongside Li_(2)O_(2)during oxygen *** situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture,as demonstrated by the air permeability *** present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.

关键词： Solid polymer electrolyte Lithium-oxygen batteries Polyrotaxane ion conductivity Hydrophobic chain

Fabrication and Properties of SiB6-B4c with Phenolic Resin as a carbon Source

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Journal of Materials Science & Technology 2008年第1期24卷 102-104页

作者： G. c.hwang J.Matsushita United Graduate School of Science and Engineering Tokai University 1117 Kitakaname Hiratsuka 259-12921 Japan

Si-B-c ceramic composites were synthesized using SiB-6,B-4c,and phenolic resin as a carbon source by pressureless sintering in an Ar ***,the Si-B-c ceramic composites were fabricated to determine their potential for applications as high hardness and high temperature *** X-ray diffraction patterns of sintered bodies of SiB-6-B-4c with carbonized phenolic resin can be seen that SiB-6 and c changed to B-4c and *** this study,it is obtained that carbonized phenolic resin is good addition material as a reaction material comparing to carbon powder at 1683 k for 1 h by pressureless sintering in an Ar atmosphere.

关键词： Silicon boride Boron carbide Phenolic resin

Strain hardening rate dependency of deformation shape,strain distribution,and contact pressure during wire flat rolling

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Journal of Iron and Steel Research International 2023年第3期30卷 475-486页

作者： Joong-ki hwang School of Mechatronics Engineering Korea University of Technology and EducationCheonan 31253Republic of Korea

The effect of the strain hardening exponent(n)of a material on the changes in shape,strain inhomogeneity,and contact pressure was investigated during wire flat rolling to understand its effect on the deformation behavior of a flat-rolled wire and to determine the optimal working conditions with *** deformation behaviors of wires with various n values were systematically compared using finite element *** shape of the deformed wire was found to depend on the n value of the *** the contact width and lateral spreading of the wire decrease with increasing n,resulting in a large reduction in area with the n *** strain homogeneity of the wire increases with the n value of the *** improvement in the strain homogeneity with the n value is attributable to two factors:a lower strain concentration in the central region and a higher overall elongation as n *** addition,the average effective strain of the wire cross section decreases with the n value of a material during wire flat *** contact pressure distribution on the surface of the wire differs significantly depending on the n *** materials with a low n value,the contact pressure exhibits a higher value at the entry and edge zones of the contact *** contrast,materials with high n values exhibit a higher contact pressure at the exit *** behavior can be explained by the strain hardening behavior of the material during wire flat rolling.

关键词： Strain hardening exponent Wire flat rolling Shape change Strain inhomogeneity contact pressure

Effect of drawing speed on microstructure distribution and drawability in twinning-induced plasticity steel during wire drawing

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Journal of Iron and Steel Research International 2020年第5期27卷 577-587页

作者： Joong-ki hwang School of Mechanical Engineering Tongmyong UniversityBusan 48520Republic of Korea

The effect of drawing speed on temperature rise and microstructure distribution in twinning-induced plasticity(TWIP)steel during wire drawing has been investigated to improve drawability for wire rod *** wire drawing process is performed at room temperature,heat is generated due to the plastic deformation and friction at the wire-die *** steel wires subjected to the low drawing speed(LD)of 0.5 m/min and the high drawing speed(HD)of 5.0 m/min were analyzed using the numerical simulation and electron backscatter diffraction ***,the specimens subjected to the HD had a higher drawability by about 18%compared to the LD,which is totally different from the general behavior of plain carbon pearlitic *** LD wire had uniform temperature distribution along the radial direction during wire *** contrast,the HD wire had a temperature gradient along the radial direction due to the higher frictional effect at surface:the minimum temperature of 58℃ at center area and the maximum temperature of 143 c at surface *** higher stacking fault energy of HD wire at the surface area due to the high temperature rise retarded twinning rate,resulting in the prevention of fast exhaustion in ductility in comparison with the LD wires since the earlier depletion of twins at surface area is known as the main reason for the fracture of TWIP steel during wire ***,HD process delayed the fracture strain of wire and increased the uniformity of microstructure and mechanical properties along the radial direction.

关键词： Twinning-induced plasticity steel Wire drawing Deformation twin Drawing speed Temperature rise

Design Features and commissioning of the Versatile Experiment Spherical Torus (VEST) at Seoul National University

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Plasma Science and Technology 2013年第3期15卷 244-251页

作者： k.J.cHUNG Y.H.AN B.k.JUNG H.Y.LEE c.SUNG Y.S.NA T.S.HAHM Y.S.hwang Department of Nuclear Engineering Seoul National University

A new spherical torus called VEST （Versatile Experiment Spherical Torus） is designed, constructed and successfully commissioned at Seoul National University. A unique design feature of the VEST is two partial solenoid coils installed at both vertical ends of a center stack, which can provide sufficient magnetic fluxes to initiate tokamak plasmas while keeping a low aspect ratio configuration in the central region. According to initial double null merging start-up scenario using the partial solenoid coils, apprdpriate p6wer supplies for driving a toroidal field coil, outer poloidal field coils, and the partial solenoid coils are fabricated and successfully commissioned. For reliable start-up, a pre-ionization system with two cost-effective homemade magnetron power supplies is also prepared. In addition, magnetic and spectroscopic diagnostics with appropriate data acquisition and control systems are well prepared for initial operation of the device. The VEST is ready for tokamak plasma operation by completing and commissioning most of the designed components.

关键词： spherical torus partial solenoids double null merging start-up

Seismic health monitoring of Rc frame structures using smart aggregates

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Earthquake Engineering and Engineering Vibration 2013年第1期12卷 25-32页

作者： Wen-I Liao c.H.Lin J.S.hwang G.Song Department of civil Engineering Taipei University of Techology (NTUT) Department of construction Engineering Taiwan University of Science and Technology Department of Mechanical Engineering University of Houston

Structural health monitoring of Rc structures under seismic loads has recently attracted much attention in the earthquake engineering research community. In this study, a piezoceramic-based device called ＂smart aggregate＂ was used for the health monitoring of Rc frame structures under earthquake excitations. Three Rc moment frames instrumented with smart aggregates were tested using a shaketable with different ground excitation intensities. Distributed piezoceramic- based smart aggregates were embedded in the Rc structures and used to monitor their health condition during the tests. The sensitivity and effectiveness of the proposed piezoceramic-based approach were investigated and evaluated by analyzing the measured responses. The displacement ductility demand of the structural members was calculated and compared with the damage index determined from the health monitoring system. The comparison shows that the damage index is compatible with the calculated ductility demand.

关键词： smart aggregate health monitoring Rc frame shaketable piezoceramic

Bee Venom Acupuncture Induced Skin Patch Discoloration Persisting for More than 3 Years:A case Report

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chinese Journal of Integrative Medicine 2021年第10期27卷 774-777页

作者： Ji Hye hwang Department of Acupuncture&Moxibustion Medicine College of Korean MedicineGachon UniversitySeongnam(13120)Republic of Korea

Bee venom(BV),one of the most commonly encountered types of animal venom,consists of a mixture of chemical agents that cause allergic reactions in the human body.⑴BV therapy,in which BV is exploited for medicinal purposes,is available worldwide,mainly used in Asia,Eastern Europe,and South America.(2)BV therapy has been applied to treat a diverse set of diseases including various musculoskeletal conditions such as arthritis and rheumatism,arthralgia,chronic recalcitrant neuralgia,(3-5)Parkinson's disease,(6,7)postherpetic neuralgia,(8)and morphea.(9)Although the therapeutic utility of BV has been demonstrated,extensive studies regarding the safety of BV as a therapeutic agent have identified potential side effects,ranging from minor skin reactions that typically resolve over several days to severe life-threatening immune responses such as anaphylaxis.

关键词： Acupuncture diseases Bee

Thermal stress analysis method considering geometric effect of risers in sand mold casting process

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china Foundry 2014年第6期11卷 531-536页

作者： S.Y.kwak H.Y.hwang c.cho e-Design R&D Group Korea Institute of Industrial Technology (KITECH) Department of Virtual Engineering Korea University of Science and Technology(UST) Department of Mechanical Engineering Inha University

Solidif ication and f luid f low analysis using computer simulation is a current common practice. There is also a high demand for thermal stress analysis in the casting process because casting engineers want to control the defects related to thermal stresses, such as large deformation and crack generation during casting. The riser system is an essential part of preventing the shrinkage defects in the casting process, and it has a great inf luence on thermal phenomena. The analysis domain is dramatically expanded by attaching the riser system to a casting product due to its large volume, and it makes FEM mesh generation diff icult. However, it is diff icult to study and solve the above proposed problem caused by riser system using traditional analysis methods which use single numerical method such as FEM or FDM. In this paper, some research information is presented on the effects of the riser system on thermal stress analysis using a FDM/FEM hybrid method in the casting process simulation. The results show the optimal conditions for stress analysis of the riser model in order to save computation time and memory resources.

关键词： thermal stress sand mold casting riser numerical analysis hybrid method simulation

Small Zeros of Additive Forms in Several Variables

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Acta Mathematica Sinica,English Series 1998年第1期14卷 57-66页

作者： J. S. hwang Institute of Mathematics Academia Sinica Taipei Taiwan 11529 China

Let f（X） be an additive form defined by f（X）=f（x1. x2,…,xs）=σ1α1x1k+σα2x2k+…+σsαsxsk, where αo≠0 is integer, i=1, 2,…, s. In 1979, Schmidt proved that if ε>0 then there is a large constant c（k, ε） such that for s≥c（k, ε） the equation f（X）=0 has a nontrivial integer solution in σ1. σ2,…σs, x1, x2…,xs satisfying σi=±1 and |xi|≤Aε, i=1, 2.…,s where A=max|ai|. Schmidt did not estimate this constant c（k. ε） since it would be extremely large. In this paper, we prove the following result: Theorem 1 If log A≤1/ε,then c（k,ε）≤max （2/ε,20）; if log A>1/ε,A is sufficiently larye and 1/2A≤5≤|ai|≤A,i=1. 2,…, s, then c（k,ε）≤c1c2p and if the last condition is omitted, then c（k. ε）≤[4/ε]c1c2,where c1={2k+1 for≤k≤11 [5k2log k] for k≥12, c2=100c1k22k+c12 and p=2[log 2c1/ε]. We note that the inequality in the first case is sharp but not in the second case.

关键词： Additive form Subset sums Small zeros