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Evaluation of microstructure and mechanical properties of Mg-xce-0.5Zn alloys by nano-indentation

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Transactions of Nonferrous Metals Society of china 2010年第7期20卷 1240-1243页

作者： k.c.park B.H.kIM Y.H.park I.M.park Department of Material Science and Engineering Pusan National UniversitySan 30 Jangjeon-dongGeumjeong-guBusan 609-735Korea

The microstructure and mechanical properties of Mg-xce-0.5Zn （x=0.5, 1.5, 2.5, molar fraction, %） alloys were examined using a nano-indentation technique. The alloys were fabricated using a vacuum induction melting method under an argon atmosphere The microstruetures of Mg-xce-0.5Zn alloys mainly consist ofa-Mg and eutectic Mg12ce phase. The volume fraction and size of the eutectic Mgl2ce phase increase with increasing ce contents. Nano-indentation test results show that the indentation hardness and elastic modulus of the eutectic Mg12ce phase are higher than those of the a-Mg matrix. In addition, the mean indentation hardness and elastic modulus of the Mg-xce-0.5Zn alloys increase with the ce addition amount increasing.

关键词： Mg alloys Mg-ce-Zn rare earth microstructure mechanical properties nano-indentation

Derivation of Modified Stress-Strain Tensor for Wrinkled Membrane by Using Projection Matrix

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Derivation of Modified Stress-Strain Tensor for Wrinkled Mem...

Prominent cycling reversibility and kinetics enabled by caTiO3 protective layer on Zn metal for aqueous Zn-ion batteries

The Sixth World congress on computational Mechanics in conjunction with the Second Asian-Pacific congress on computational Mechanics

作者： Takeshi Akita kyoichi Nakashino M.c.Natori k.c.park Japan Aerospace Exploration Agency (JAXA) The Institute of Space and Astronautical Science 3-1-1 Yoshinodai Sagamihara kanagawa 229-8510 Japan Japan Aerospace Exploration Agency (JAXA) The Institute of Space and Astronautical Science 3-1-1 Yoshinodai Sagamihara kanagawa 229-8510 Japan Japan Aerospace Exploration Agency (JAXA) The Institute of Space and Astronautical Science 3-1-1 Yoshinodai Sagamihara kanagawa 229-8510 Japan center for Aerospace Structures University of colorado Boulder colorado 80309-0429 USA

Recently, membranes attract great interest in the field of space structure s engineering due to such abilities as high packaging ratio and light weight proper ty. Since membranes have little resistance against compressive stresses, wrinkles may be formed over partial or entire regions of the membranes. The presence of such wrinkles could cause significant deterioration in the performance of membrane structures. Therefore, it is of great importance to develop efficient mathematical model accounting for wrinkling phenomenon.

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Journal of Energy chemistry 2025年第1期100卷 245-258页

作者： Gaeun Lee Yong Nam Ahn Seongjoon So chanwoo park Jong-Seong Bae Taehyun park Il Tae kim Jaehyun Hur School of chemical Biological and Battery Engineering Gachon University Seongnam Busan center Korea Basic Science Institute

Aqueous Zn-ion batteries （AZIBs） have received considerable attention owing to their various advantages such as safety,low cost,simple battery assembly conditions,and high ionic ***,they still suffer from serious problems,including uncontrollable dendrite growth,corrosion,hydrogen evolution reaction （HER） from water decomposition,electrode passivation,and unexpected *** creation of a uniform artificial nanocrystal layer on the Zn anode surface is a promising strategy for resolving these ***,we propose the use of a perovskite caTiO3（cTO） protective layer on Zn（cTO@Zn） as a promising approach for improving the performance of *** cTO artificial layer provides an efficient pathway for Zn ion diffusion towards the Zn metal because of the high dielectric constant （εr=180） and ferroelectric characteristics that enable the alignment of dipole moments and redistribute the Zn2+ions in the cTO *** avoiding the direct contact of the Zn anode with the electrolyte solution,the uneven dendrite growth,corrosion,parasitic side reactions,and HER are mitigated,while cTO retains its mechanical and chemical robustness during ***,cTO@Zn demonstrates an improved lifespan in a symmetric cell configuration compared with bare ***@Zn shows steady overpotential （～68 m V） for 1500 h at 1 mA cm-2/0.5 mA h cm-2,excelling bare ***,when paired with the V2O5-c cathode,the cTO@Zn//V2O5-c full battery delivers 148.4 mA h g-1（based on the mass of the cathode） after 300 *** study provides new insights into Zn metal anodes and the development of high-performance AZIBs.

关键词： Artificial layer Dielectric constant Zn metal anode Zinc aqueous battery

Liquid-liquid extraction and separation of total rare earth(RE) metals from polymetallic manganese nodule leaching solution

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Journal of Rare Earths 2015年第2期33卷 207-213页

作者： P.k.Parhi k.H.park c.W.Nam J.T.park Mineral Resources Research Division Korea Institute of Geoscience & Mineral Resources (KIGAM)Daejeon 305-350 Republic of Korea School of Applied Science and center of Industrial Technology KIIT UniversityBhubaneswar 751024 Odisha India

The study on the solvent extraction for quantitative and selective separation of total rare earth metals from the polymetallic nodule leach liquor was investigated. The typical leach liquor bearing 0. 094 g/L total rare earth, 0. 23 g/L Mn, 0.697 g/L cu, 0.2 g/L Fe, 0.01 g/L co and 0.735 g/L Ni was subjected to the removal iron content by precipitation method using ca（OH）2 at pH 3.95, prior to solvent extraction of rare earth metals. Three different organo-phosphoric acid reagents（D2EHPA, Pc88 A, cyanex 272） were used to ascertain their performances and selectivity towards the loading of rare earth metals in presence of other base metals. Based on the results of eq. pH effect, the performances of above three extractants followed the order as： D2EHPA〉Pc88A〉cyanex 272. To ensure the absence of extraction of base metals（cu, co, Ni）, the eq. pH of the solution was optimized at the level of 2.21, though higher rare earth metal extraction efficiency was observed at higher eq. pH with either of the extractants. The complete process flow diagram for substantial recovery of total rare earth was developed using D2 EHPA. Extraction isotherm plot was constructed at A：O=12：1, 3-stages and pHe=2.21, using 0.8 mol/L D2 EHPA and the predicted condition of this study was further confirmed by 6-cycles counter current Simulation（ccS） study. The stripping of total rare earth from loaded organic phase（LO） was conducted using Hcl solution. Mc-cabe Thiele diagram study carried out at A：O=1：5 using 4 mol/L Hcl showed that three theoretical stages were needed for quantitative stripping of total rare earth. The subsequent stripped solution resulted thus led to contain total rare earth of 5.6 g/L indicating a very high enrichment of total metals by solvent extraction（SX） process.

关键词： total rare earth (RE) metals SX D2EHPA Hcl deep sea nodule

Effect of monovalent charge compensators on the photoluminescence properties of ca_(3)(PO_(4))_(2):Tb^(3+),A^(+)(A=Li,Na,k)phosphors

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Journal of Materials Science & Technology 2021年第23期82卷 187-196页

作者： G.W.Jung k.park Faculty of Nanotechnology and Advanced Materials Engineering Sejong UniversitySeoul05006Republic of Korea

ca_(3-x)(PO_(4))_(2):xTb^(3+)(0.2≤x≤0.4),ca_(2.3)(PO_(4))_(2):0.35 Tb^(3+),0.35 A^(+)(A=Li,Na,k),and ca_(2.3)(PO_(4))_(2):0.35 Tb^(3+),yLi^(+)(0.35≤y≤0.455)phosphors were prepared by solid-state *** the prepared phosphors formed a rhombohedral unit cell with the R3c space *** improve the photoluminescence(PL)properties of the ca_(2.65)(PO_(4))_(2):0.35 Tb^(3+)phosphor,monovalent charge compensators such as Li^(+),NA^(+),and k^(+)were added to the ca_(2.65)(PO_(4))_(2):0.35 Tb^(3+)*** charge compensators acted as fluxes,so they improved the *** excitation and emission properties were significantly improved through the incorporation of charge *** particular,among the charge compensators,Li^(+)ion substantially enhanced the emission intensity and color ***,considering the evaporation of Li_(2)cO_(3)during the annealing process,we optimized the concentration of Li^(+)charge compensator to enhance its PL ***,the green emission intensity of the ca_(2.3)(PO_(4))_(2):0.35 Tb^(3+),0.385 Li^(+)phosphor was 260%higher than that of the ca_(2.65)(PO_(4))_(2):0.35 Tb^(3+)*** believe that the effect of charge compensators on the PL properties and the optimum concentration of Li^(+)cha rge compensator are useful for the design of phosphors in light-emitting diodes.

关键词： Optical properties ca_(3)(PO_(4))_(2) Emission Excitation charge compensator

HYERS—ULAM—RASSIAS STABILITY OF QUADRATIc FUNcTIONAL EQUATIONS IN BANAcH MODULES OVER A c^＊—ALGEBRA

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chinese Annals of Mathematics,Series B 2003年第2期24卷 261-266页

作者： c. park J. park J. SHIN Department of Mathematics Chungnam National University DaeJeon 305-764 South Korea.Department of Mathematics Chungnam National University DaeJeon 305-764 South Korea.Department of Mathematics Chungnam National University DaeJeon 305-764 South Korea.

The authors prove the Hyers-Ulam-Rassias stability of the quadratic mapping in Banachmodules over a unital c*-algebra, and prove the Hyers-Ulam-Rassias stability of the quadraticmapping in Banach modules over a unital... 详细信息

关键词： Stability B-quadratic Functional equation Banach module over Banach algebra

Photocatalysts for degradation of dyes in industrial effluents:Opportunities and challenges

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Nano Research 2019年第5期12卷 955-972页

作者： Hassan Anwer Asad Mahmood Jechan Lee ki-Hyun kim Jae-Woo park Alex c.k.Yip Department of civil and Environmental Engineering Hanyang University222 Wangsimni-roSeoul 04763Republic of Korea Department of Environmental and Safety Engineering Ajou UniversitySuwon 16499Republic of Korea Department of chemical and Process Engineering University of CanterburyChristchurch 8041New Zealand

Discharging dye contaminants into water is a major concern around the *** a variety of methods to treat dye-contaminated water,photocatalytic degradation has gained attention as a tool for treating the colored ***,we review the recent advancements in photocatalysis for dye degradation in industrial effluents by categorizing photocatalyst materials into three *** generation photocatalysts are composed of single-component materials (e.g.,TiO2,ZnO,and cdS),while second generation photocatalysts are composed of multiple components in a suspension (e.g.,WO3/NiWO4,BiOl/ZnTiOa,and c3N4/Ag3VO4).Photocatalysts immobilized on solid substrates are regarded as third generation materials (e.g.,FTO/WO3-ZnO,Steel/TiO2-WO3,and Glass/P-TiO2).Photocatalytic degradation mechanisms,factors affecting the dye degradation,and the lesser-debated uncertainties related to the photocatalysis are also discussed to offer better insights into environmental ***,quantum yields of different photocatalysts are calculated,and a performance evaluation method is proposed to compare photocatalyst systems for dye ***,we discuss the present limitations of photocatalytic dye degradation for field applications and the future of the technology.

关键词： photocatalyst dye wastewater degradation mechanism performance evaluation

Thermal fronts and cross-frontal heat flux in the southern Huanghai Sea and the East china Sea

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Acta Oceanologica Sinica 2008年第5期27卷 1-20页

作者： park Sunghyea cHU Peter c Department of Oceanography Naval Postgraduate School

Synoptic features in/around thermal fronts and cross-frontal heat fluxes in the southern Huanghai./Yellow Sea and East china Sea （HES） were examined using the data collected from four airborne expendable bathythermograph surveys with horizontal approxmately 35 km and vertical 1 m（from the surface to 400 m deep） spacings. Since the fronts are strongly affected by HES current system, the synoptic thermal features in/around them represent the interaction of currents with surrounding water masses. These features can not be obtained from climatological data. The identified thermal features are listed as follows ：（ 1 ） multiple boundaries of cold water, asymmetric thermocline intrusion, locally-split front by homogeneous water of approxmately 18 ℃, and mergence of the front by the Taiwan Warm current in/around summertime southern cheju - changjiang/Yangtze front and Tsushima front; （2） springtime frontal eddy-like feature around Tsushima front; （3） year-round cyclonic meandering and summertime temperature-inversion at the bottom of the surface mixed layer in cheju - Tsushima front; and （4） multistructure of kuroshio front. In the kuroshio front the mean variance of vertical temperature gradient is an order of degree smaller than that in other HES fronts. The southern cheju- changjiang front and cheju -Tsushima front are connected with each other in the summer with comparable cross-frontal temperature gradient. However, cross-frontal heat flux and lateral eddy diffusivity are stronger in the southern cheju - changjiang front. The cross-frontal heat exchange is the largest in the mixing zone between the modified Huanghai Sea bottom cold water and the Tsushima Warm current, which is attributable to enhanced thermocline intrusions.

关键词： southern Huanghai Sea and East china Sea AXBT synoptic thermal front cross-frontal heat flux lateral eddy diffusivity

Optimal design of V-type ultrasonic motor

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Journal of central South University 2010年第6期17卷 1247-1250页

作者： JEONG S S park c H park T G School of Mechatronics Changwon National UniversityChangwon 641773Korea

V-type ultrasonic linear motor fabricated using a simple punching technique was proposed to utilize as an actuator of small precision *** stator of the motor is composed of a thin elastic body and four ceramics attached to the upper and bottom areas of the *** ceramics have each direction of *** two harmonic voltages with a 90° phase difference are applied to the ceramics,symmetric and anti-symmetric displacements will generate at the tip to produce an elliptical motion.A finite element analysis(ATILA) was conducted to simulate the motion pattern for the contact tip of the *** develop a model that generates the maximum displacement at contact tip,the FEM program was used for various *** addition,an optimal model was chosen by considering the magnitude and shape of the displacement according to changes in *** maximum elliptical displacement is shown by W2L11 model,which has a ratio of ceramic width to length of 1:***,the displacement of the contact tip is reduced by the bucking phenomenon if the ratio is larger than 1:6.

关键词： ultrasonic motor piezo-actuator finite element method optimal design elliptical motion