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Silver-palladium alloy deposited by DC magnetron sputtering method as lubricant for high temperature application

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中国有色金属学会会刊：英文版 2009年第4期19卷 1001-1004页

作者： Jung-Dae KWON sung-hun lee Koo-Hyun lee Jong-Joo RHA Kee-Seok NAM Sang-Hoon CHOI Dong-Min lee Dong-Il KIM Materials Processing Division Korea Institute of Materials Science Technology Research & Development Institute Korea Plant Service and Engineering

The silver-palladium(Ag-Pd) alloy coating as a solid lubricant was investigated for its application to the high temperature stud bolts used in nuclear power plants.A hex bolt sample was prepared in the following steps:1) bolt surface treatment using alumina grit blasting for cleaning and increasing the surface area;2) nickel(Ni) film coating as a glue layer on the surface of the bolt;and 3) Ag-Pd alloy coating on the Ni *** films were deposited by using a direct current(DC) magnetron sputtering *** thickness and composition of the Ag-Pd alloy film have effect on the friction coefficient,which was determined using axial force measurement.A 500 nm-thick Ag-Pd(80-20,molar ratio) alloy film has the lowest friction coefficient of 0.109.A cyclic test was conducted to evaluate the durability of bolts coated with either the Ag-Pd(80-20) alloy film or N-5000 *** a cycle,the bolts were inserted into a block using a torque wrench,which was followed by heating and *** only one cycle,it was not possible to remove the bolts coated with the N-5000 oil from the ***,the bolts coated with the Ag-Pd(80-20) alloy could be easily removed up until 15 cycles.

关键词：银钯合金直流电高温润滑剂沉积磁控溅射法固体润滑涂层高温螺栓

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

Ru/NiMnB spherical cluster pillar for highly proficient green hydrogen electrocatalyst at high current density

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Journal of Energy Chemistry 2025年第1期100卷 397-408页

作者： Md Ahasan Habib Shusen Lin Mehedi Hasan Joni Sumiya Akter Dristy Rutuja Mandavkar Jae-hun Jeong Jihoon lee Department of Electronic Engineering College of Electronics and Information Kwangwoon University

Advanced OER/HER electrocatalytic alternatives are crucial for the wide adaptation of green hydrogen ***,Ru/NiMnB spherical cluster pillar （SCP）,denoted as Ru/NiMnB,is synthesized using a combination of electro-deposition and hydrothermal *** investigation of Ru doping in the NiMnB matrix revealed significant improvements in electrocatalytic *** Ru/NiMnB SCPs demonstrate superior OER/HER activity with low overpotentials of 150 and 103 mV at 50mA/cm2in 1 M KOH,making them highly competitive with state-of-the-art ***,the Ru/NiMnB SCPs exhibit a low 2-E cell voltage of 2.80 V at ultra-high current density of 2,000 m A/cm2in 1 M KOH,outperforming the standard benchmark electrodes of RuO2||Pt/C,thereby positioning Ru/NiMnB as one of the best bifunctional *** SCPs exhibit exceptional high-current characteristics,stability and corrosion resistance,as evidenced by continuous operation at 1,000 mA/cm2high-current density for over 150 h in 6 M KOH at elevated temperatures under harsh industrial *** a small amount of Ru incorporation significantly enhances the electrocatalytic performances of NiMnB,attributed to increased active sites and improved intrinsic properties such as conductivity,adsorption/desorption capability and reaction ***,Ru/NiMnB SCPs present a promising bi-functional electrode concept for efficient green H2production.

关键词： Advanced electrocatalyst High current Corrosion resistance Industrial requirement

Enhancement of motor functional recovery in thoracic spinal cord injury: voluntary wheel running versus forced treadmill exercise

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Neural Regeneration Research 2025年第3期20卷 836-844页

作者： Do-hun lee Dan Cao Younghye Moon Chen Chen Nai-Kui Liu Xiao-Ming Xu Wei Wu Spinal Cord and Brain Injury Research Group Stark Neurosciences Research InstituteIndiana University School of MedicineIndianapolisINUSA Department of Neurological Surgery Indiana University School of MedicineIndianapolisINUSA Department of Neuroscience Baylor College of MedicineHoustonTXUSA

Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery and morphological changes following thoracic contusive spinal cord injury. After a 7-day recovery period after spinal cord injury, mice were assigned to either a trained group(10 weeks of voluntary running wheel or forced treadmill exercise) or an untrained group. Bi-weekly assessments revealed that the exercise-trained group, particularly the voluntary wheel exercise subgroup, displayed significantly improved locomotor recovery, more plasticity of dopaminergic and serotonin modulation compared with the untrained group. Additionally, exercise interventions led to gait pattern restoration and enhanced transcranial magnetic motor-evoked potentials. Despite consistent injury areas across groups, exercise training promoted terminal innervation of descending axons. In summary, voluntary wheel exercise shows promise for enhancing outcomes after thoracic contusive spinal cord injury, emphasizing the role of exercise modality in promoting recovery and morphological changes in spinal cord injuries. Our findings will influence future strategies for rehabilitation exercises, restoring functional movement after spinal cord injury.

关键词： behavioral assessment motor function neural plasticity running wheel exercise spinal cord injury treadmill exercise voluntary exercise

Regulation of sleep by astrocytes in the hypothalamic ventrolateral preoptic nucleus

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Neural Regeneration Research 2025年第4期20卷 1098-1100页

作者： Jae-Hong Kim Ruqayya Afridi Il-sung Jang Maan Gee lee Kyoungho Suk Brain Korea 21 four KNU Convergence Educational Program of Biomedical Sciences for Creative Future Talents School of MedicineKyungpook National UniversityDaeguRepublic of Korea Department of Pharmacology School of MedicineKyungpook National UniversityDaeguRepublic of Korea Department of Pharmacology School of DentistryKyungpook National UniversityDaeguRepublic of Korea Brain Science&Engineering Institute Kyungpook National UniversityDaeguRepublic of Korea

Astrocytes are functionally dynamic cells that support neurons in multiple ways throughout an organism’s *** astrocytic regulation of neuronal activity has been increasingly recognized in recent *** are now recognized as playing a more complex role than mere bystanders in the central nervous ***,their role in regulating the sleep neurocircuitry is not well *** this perspective,we highlight the role of astrocytes in sleep modulation,with a particular focus on regulatory mechanisms related to the ventrolateral preoptic nucleus(VLPO)of the *** briefly discuss recent literature reporting the role of VLPO astrocytes in regulating sleep-associated behaviors.

关键词： sleep ventrolateral astrocytes

Pancreatic stent improves the success rate of needle-knife papillotomy in patients with difficult biliary cannulation

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World Journal of Gastroenterology 2025年第1期31卷 58-67页

作者： Mu-Hsien lee Cheng-Hui Lin Chi-Huan Wu Yung-Kuan Tsou Kai-Feng sung Sheng-Fu Wang Nai-Jen Liu Department of Gastroenterology and Hepatology Chang Gung Memorial Hospital and Chang Gung University College of MedicineTaoyuan 33305Taiwan School of Medicine Chang Gung UniversityTaoyuan 33305Taiwan

BACKGROUND Needle-knife precut papillotomy(NKP)is typically performed ***,it remains unclear whether pancreatic stent(PS)placement can improve the outcomes of *** To explore whether PS placement improves the success rate of NKP in patients with difficult biliary *** This single-center retrospective study included 190 patients who underwent NKP between January 2017 and December 2021 after failed conventional biliary *** cases with incidental pancreatic duct cannulation during conventional biliary cannulation,the decision for pre-NKP PS placement was made at the endoscopist's *** primary outcome was the difference in the NKP success rate between patients with and without PS placement;the secondary outcome was the adverse event *** Among the 190 participants,82 received pre-NKP PS(PS-NKP group)whereas 108 did not[freehand or freehand NKP(FH-NKP)group].Post-NKP selective biliary cannulation was successful in 167(87.9%)patients,and the PS-NKP had a significantly higher success rate than the FH-NKP group(93.9%vs 83.3%,P=0.027).The overall adverse event rates were 7.3%and 11.1%in the PS-NKP and FH-NKP groups,respectively(P=0.493).A periampullary diverticulum(PAD)and significant intraoperative bleeding during NKP were independently associated with NKP failure;however,a pre-NKP PS was the only predictor of NKP *** the 44 participants with PADs,the PS-NKP group had a non-significantly higher NKP success rate than the FH-NKP group(87.5%and 65%,respectively;P=0.076).CONCLUSION PS significantly improved the success rate of NKP in patients with difficult biliary cannulation.

关键词： Difficult biliary cannulation Endoscopic retrograde cholangiopancreatography Needle-knife papillotomy Pancreatic stent Selective biliary cannulation

Dynamic deformation behavior and microstructural evolution during high-speed rolling of Mg alloy having non-basal texture

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Journal of Materials Science & Technology 2019年第4期35卷 473-482页

作者： Sang-Hoon Kim Jeong hun lee Chong Soo lee Jonghun Yoon sung Hyuk Park School of Materials Science and Engineering Kyungpook National University Ulsan Regional Division Korea Institute of Industrial Technology Graduate Institute of Ferrous Technology Pohang University of Science and Technology Department of Mechanical Engineering Hanyang University

The dynamic deformation behaviors and resultant microstructural variations during high-speed rolling(HSR) of a Mg alloy with a non-basal texture are investigated. To this end, AZ31 alloy samples in which the basal poles of most grains are predominantly aligned parallel to the transverse direction(TD) are subjected to hot rolling with different reductions at a rolling speed of 470 m/min. The initial grains with a TD texture are favorable for {10–12} twinning under compression along the normal direction(ND); as a result, {10–12} twins are extensively formed in the material during HSR, and this consequently results in a drastic evolution of texture from the TD texture to the ND texture and a reduction in the grain size. After the initial grains are completely twinned by the {10–12} twinning mechanism, {10–11} contraction twins and {10–11}-{10–12} double twins are formed in the {10–12} twinned grains by further *** the contraction twins and double twins have crystallographic orientations that are favorable for basal slip during HSR, dislocations easily accumulate in these twins and fine recrystallized grains nucleate in the twins to reduce the increased internal strain energy. Until a rolling reduction of 20%, {10–12}twinning is the main mechanism governing the microstructural change during HSR, and subsequently,the microstructural evolution is dominated by the formation of contraction twins and double twins and the dynamic recrystallization in these twins. With an increase in the rolling reduction, the average grain size and internal strain energy of the high-speed-rolled(HSRed) samples decrease and the basal texture evolves from the TD texture to the ND texture more effectively. As a result, the 80% HSRed sample, which is subjected to a large strain at a high strain rate in a single rolling pass, exhibits a fully recrystallized microstructure consisting of equiaxed fine grains and has an ND basal texture without a TD texture component.

关键词： Magnesium alloy High-speed rolling Texture Dynamic recrystallization Twinning

Synthesis and Characterization of SiO_2 Coated γ-Fe_2O_3 Nanocomposite Powder for Hyperthermic Application

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Journal of Materials Science & Technology 2010年第4期26卷 333-336页

作者： Ji-hun Yu Jai-sung lee Yong-Ho Choa Heinrich Hofmann Korea Institute of Materials Science Changwon 641-831 Korea Division of Materials and Chemical Engineering Hanyang University Ansan 426-791 Korea Swiss Federal Institute of Technology at Lausanne Lausanne CH-1015 Switzerland

SiO2 coated γ-Fe2O3 nanocomposite powder has been successfully synthesized by chemical vapor condensation process and its feasibility on hyperthermic application was investigated in this study. The power loss of SiO2 coated γ-Fe2O3 nanocomposite powder which means the magnetic heating effect under alternative magnetic field was much higher than the single phase γ-Fe2O3 nano powder due to the very fine size under 20 nm and well dispersion in biologically compatible SiO2 matrix. The superparamagnetism and hyperthermic property of SiO2 coated γ-Fe2O3 nanocomposite powder were discussed in terms of microstructural development in this study.

关键词： Hyperthermia Nano-Bio Chemical vapor condensation Silica coated iron oxide nanoparticle Superparamagnetism

Improved tensile properties of AZ31 Mg alloy subjected to various caliber-rolling strains

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Journal of Magnesium and Alloys 2019年第3期7卷 381-387页

作者： Jeong hun lee Byung Je Kwak Taein Kong sung Hyuk Park Taekyung lee Advanced Forming Process R&D Group Korea Institute of Industrial TechnologyUlsan 44413Republic of Korea School of Mechanical Engineering Pusan National UniversityBusan 46241Republic of Korea School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

A multi-pass caliber rolling has attracted attentions as an alternative to severe plastic deformation *** present study enhanced strength and ductility of AZ31 Mg alloy simultaneously through the application of caliber *** improving trends in tensile properties were interpreted with various caliber-rolling *** oval/circular-shaped calibers imposed a high plastic strain at the center of crosssection,leading to effective grain refinement to submicron *** work also confirmed the texture randomizing effect of caliber *** microstructural evolutions gave rise to the fabrication of high-strength ***,the caliber-rolled AZ31 Mg alloys exhibited an improvement in ductility as compared to the as-received sheet-rolled *** was discussed in terms of activation of non-basal slip systems and suppression of mechanical *** study successfully proved the possibility of caliber rolling to produce a bulk Mg rod with enhanced tensile properties.

关键词： Magnesium AZ31 alloy Caliber rolling Grain refinement Texture randomization Mechanical improvement