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Reciprocating friction characteristics of magneto-rheological fluid for aluminum under magnetic field

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Transactions of Nonferrous Metals Society of China 2014年第1期24卷 171-176页

作者：张鹏 Kwang-heelee chul-heelee Department of Mechanical Engineering Inha University

Reciprocating friction characteristics of magneto-rheological （MR） fluid for aluminum under a magnetic field at different loads and oscillation frequencies were studied when MR fluids were worked in reciprocating motions such as in dampers for automobiles, and surface polishing and other finishing. Thus, experiments were carried out to evaluate the reciprocating friction characteristic of MR fluid for aluminum. The obtained data from the tests are sorted in groups depending on various loads and oscillation frequencies, to analyze the relationship between test condition and travel cycle. Surfaces of specimens were compared by measuring the surface roughness and observing the surface images. The performance of reciprocating friction characteristics of MR fluid for aluminum is evaluated through analyzing the experiment results.

关键词： magneto-rheological fluid reciprocating friction aluminum magnetic field smart material

Effect of stick-slip on magneto-rheological elastomer with a magnetic field

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Friction 2017年第4期5卷 383-391页

作者： Chenglong LIAN Kwang-hee lee Jun-wook AN chul-hee lee Department of Mechanical Engineering Inha University100 InharoNam-guIncheon 22212Republic of Korea Department of Construction Machinery Engineering Inha University100 InharoNam-guIncheon 22212Republic of Korea

This study investigated the stick-slip characteristics of a magneto-rheological elastomer (MRE) against an aluminum ***,the MRE was manufactured,and a stick-slip tester was employed to evaluate the stick-slip performance of the MRE under different velocities and load conditions with and without a magnetic *** fast Fourier transform (FFT) of the friction force of the stick-slip and the roughness of the aluminum plate surface were calculated to confirm the stick-slip *** the tests,the wear surfaces were observed to evaluate the wear properties of the MRE regarding the *** showed that the stick-slip was smaller at lower *** higher velocity,the reduction of the stick-slip under a magnetic field was more clearly ***,the wear reduced with reduced stick-slip under a magnetic field.

关键词： stick-slip friction wear magneto-rheological elastomer

Sliding wear behavior of magnetorheological fluid for brass with and without magnetic field

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Transactions of Nonferrous Metals Society of China 2013年第2期23卷 400-405页

作者： Wan-Li SONG chul-hee lee Seung-Bok CHOI Department of Mechanical Engineering Inha University

A pin-on-disc wear apparatus was used to carry out the tribological experiment of brass to investigate the effect of a magnetorheological （MR） fluid on the interfacial surface with and without magnetic field. A series of tests were performed at the loads of 20-100 N and rotating speeds of 127-425 r/min for 2 h. The friction coefficient and wear rate were monitored by the wear apparatus, while the microstructures of the worn surfaces were observed by scanning electron microscope （SEM）. In addition, the chemical composition of worn surfaces was analyzed by energy dispersive X-ray spectroscopy （EDS）. Test results show different friction and wear performance of the MR fluid with and without magnetic field. At the same time, the effects of various normal loads and rotating speeds on the tribological behavior were investigated. Through the investigation of the morphologies of the wom surfaces under the magnetic field, it is found that the MR particles are clearly evident on the wom surface and the plastic flow of ridges causes the lateral extrusion. This directly indicates that abrasive wear is the predominant wear mechanism observed with MR fluid.

关键词： magnetorheological fluid sliding wear brass magnetic field friction coefficient

Ionizing terahertz waves with 260 MV/cm from scalable optical rectification

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Light(Science & Applications) 2024年第6期13卷 1075-1087页

作者： Hyeongmun Kim chul Kang Dogeun Jang Yulan Roh Sang Hwa lee Joong Wook lee Jae hee Sung Seong Ku lee Ki-Yong Kim Advanced Photonics Research Institute GISTGwangju61005Korea Department of Physics and Optoelectronics Convergence Research Center Chonnam National UniversityGwangju61186Korea Pohang Accelerator Laboratory POSTECHPohang37673Korea Center for Relativistic Laser Science Institute for Basic ScienceGwangju61005Korea Institute for Research in Electronics and Applied Physics Department of PhysicsUniversity of MarylandCollege ParkMaryland20742USA

Terahertz(THz)waves,known as non-ionizing radiation owing to their low photon energies,can actually ionize atoms and molecules when a sufficiently large number of THz photons are concentrated in time and ***,we demonstrate the generation of ionizing,multicycle,15-THz waves emitted from large-area lithium niobate crystals via phase-matched optical rectification of 150-terawatt laser pulses.A complete characterization of the generated THz waves in energy,pulse duration,and focal spot size shows that the field strength can reach up to 260 megavolts per *** particular,a single-shot THz interferometer is employed to measure the THz pulse duration and spectrum with complementary numerical *** intense THz pulses are irradiated onto various solid targets to demonstrate THz-induced tunneling ionization and plasma *** study also discusses the potential of nonperturbative THz-driven ionization in gases,which will open up new opportunities,including nonlinear and relativistic THz physics in plasma.

关键词： optical interferometer matched

Endoscopic Orbital Decompression

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中国耳鼻咽喉头颈外科 2000年第S1期10卷 27-32页

作者： chul hee lee M. D. Department of Otorhinolaryngology College of Medicine Seoul National University

Difficulties, strategies, and recent research and development of layered sodium transition metal oxide cathode materials for high-energy sodium-ion batteries

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Journal of Energy Chemistry 2024年第3期90卷 40-57,I0003页

作者： Kouthaman Mathiyalagan Dongwoo Shin Young-chul lee Department of Nano Science and Technology Convergence Gachon University1342 Seongnam-DaeroSujeong-GuGyeonggi-DoSeongnam-Si 13120Republic of Korea Department of Bio Nano Technology Gachon University1342 Seongnam-DaeroSujeong-GuGyeonggi-DoSeongnam-Si 13120Republic of Korea

Energy-storage systems and their production have attracted significant interest for practical *** are the foundation of sustainable energy sources for electric vehicles(EVs),portable electronic devices(PEDs),*** recent decades,Lithium-ion batteries(LIBs) have been extensively utilized in largescale energy storage devices owing to their long cycle life and high energy ***,the high cost and limited availability of Li are the two main obstacles for *** this regard,sodium-ion batteries(SIBs) are attractive alternatives to LIBs for large-scale energy storage systems because of the abundance and low cost of sodium *** is one of the most important components in the battery,which limits cost and performance of a *** the classified cathode structures,layered structure materials have attracted attention because of their high ionic conductivity,fast diffusion rate,and high specific ***,we present a comprehensive review of the classification of layered structures and the preparation of layered ***,the review article discusses extensively about the issues of the layered materials,namely(1) electrochemical degradation,(2) irreversible structural changes,and(3) structural instability,and also it provides strategies to overcome the issues such as elemental phase composition,a small amount of elemental doping,structural design,and surface alteration for emerging *** addition,the article discusses about the recent research development on layered unary,binary,ternary,quaternary,quinary,and senary-based O3-and P2-type cathode materials for high-energy *** review article provides useful information for the development of high-energy layered sodium transition metal oxide P2 and O3-cathode materials for practical SIBs.

关键词： O3-type P2-type Cathode materials Sodium-ion batteries Layered structure

Endoscopic Treatment of Intraorbital and IntracranialComplications of Sinusitis

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中国耳鼻咽喉头颈外科 2000年第S1期10卷 33-35页

作者： chul hee lee M. D. Department of OtorhinolaryngologyCollege of Medicne Seoul National University

Methane Emission from Rice Fields:Necessity for Molecular Approach for Mitigation

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Rice science 2024年第2期31卷 159-178页

作者： Sujeevan RAJENDRAN Hyeonseo PARK Jiyoung KIM Soon Ju PARK Dongjin SHIN Jong-hee lee Young Hun SONG Nam-Chon PAEK chul Min KIM Department of Horticulture Industry Wonkwang UniversityIksan 54538Korea Plant Molecular Biology and Biotechnology Research Center Gyeongsang National UniversityJinju 52828Korea Department of Southern Area Crop Science National Institute of Crop ScienceMiryang 50424Korea Department of Agricultural Biotechnology Seoul National UniversitySeoul 08826Korea Department of Plant Science Plant Genomics and Breeding InstituteResearch Institute of Agriculture and Life SciencesSeoul National UniversitySeoul 08826Korea

Anthropogenic methane emissions are a leading cause of the increase in global averagetemperatures,often referred to as global *** soils play a significant role in methaneproduction,where the anaerobic conditions promote the production of methane by *** fields contribute a considerable portion of agricultural methane emissions,as riceplants provide both factors that enhance and limit methane *** plants harbor both methaneproducingand methane-oxidizing *** from rice roots provide source for methaneproduction,while oxygen delivered from the root aerenchyma enhances methane *** haveshown that the diversity of these microorganisms depends on rice cultivars with some genes characterizedas harboring specific groups of microorganisms related to methane ***,there is still aneed for research to determine the balance between methane production and oxidation,as rice plantspossess the ability to regulate net methane *** agronomical practices,such as fertilizerand water management,have been employed to mitigate methane ***,studiescorrelating agronomic and chemical management of methane with productivity are ***,evidences for breeding low-methane-emitting rice varieties are scattered largely due to the absence ofcoordinated breeding *** has indicated that phenotypic characteristics,such as rootbiomass,shoot architecture,and aerenchyma,are highly correlated with methane *** reviewdiscusses available studies that involve the correlation between plant characteristics and *** emphasizes the necessity and importance of breeding low-methane-emitting rice varieties inaddition to existing agronomic,biological,and chemical *** review also delves into the idealphenotypic and physiological characteristics of low-methane-emitting rice and potential breeding techniques,drawing from studies conducted

关键词： methane emission rice breeding aerenchyma greenhouse gas radial oxygen loss

Two-stage dynamic recrystallization and texture evolution in Al-7Mg alloy during hot torsion

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1900-1911页

作者： Kwang Tae Son Chang hee Cho Myoung Gyun Kim Ji Woon lee School of Mechanical Industrialand Manufacturing EngineeringOregon State UniversityCorvallis OR 97331USA Department of Materials Science Engineering Northwestern UniversityEvanston IL 60208USA Research Institute of Industrial Science and Technology(RIST) Pohang 37673Rep.of Korea Division of Advanced Materials Engineering Kongju National UniversityCheonan 31080Rep.of Korea Center for Advanced Materials and Parts of Powders Kongju National UniversityCheonan 31080Rep.of Korea

Hot torsion tests were performed on the Al-7Mg alloy at the temperature ranging from 300 to 500℃ and strain rates between 0.05 and 5 s^(-1) to explore the progressive dynamic recrystallization(DRX)and texture *** DRX behavior of the alloy manifested two distinct stages:Stage 1 at strain of≤2 and Stage 2 at strains of≥*** Stage 1,there was a slight increase in the DRXed grain fraction(X_(DRX))with predominance of discontinuous DRX(DDRX),followed by a modest change in X_(DRX) until the transition to Stage *** 2 was marked by an accelerated rate of DRX,culminating in a substantial final X_(DRX) of~*** backscattered diffraction(EBSD)analysis on a sample in Stage 2 revealed that continuous DRX(CDRX)predominantly occurred within the(121)[001]grains,whereas the(111)[110]grains underwent a geometric DRX(GDRX)evolution without a noticeable sub-grain ***,a modified Avrami’s DRX kinetics model was utilized to predict the microstructural refinement in the Al-7Mg alloy during the DRX *** this kinetics model did not accurately capture the DDRX behavior in Stage 1,it effectively simulated the DRX rate in Stage *** texture index was employed to assess the evolution of the texture isotropy during hot-torsion test,demonstrating significant improvement(>75%)in texture randomness before the commencement of Stage *** initial texture evolution is attributed to the rotation of parent grains and the substructure evolution,rather than to an increase in X_(DRX).

关键词： Al-7Mg alloys hot deformation hot torsion tests dynamic recrystazlliation microstructure texture