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Spatial distribution and comparative evaluation of phosphorus release rate in benthic sediments of an estuary dam

International Journal of Sediment Research 2022年第3期37卷 355-369页

作者： Yongsik Song Yong-hoon jeong Chang-Min Shin Dong-Heui Kwak Geosystem Research Corporation Department of Civil Engineering Jeonbuk National University Department of Bio-Convergence Science Jeonbuk National University Water Quality Assessment Research Division National Institute of Environmental Research Department of Bioactive Materials Science Jeonbuk National University

A series of experiments and simulations were performed to ascertain the rate at which phosphorus is released using a water quality model in Saemangeum Lake, an artificially constructed lake located in an estuary. The general inflow of seawater once a day contributed to the formation of a halocline in the lake water, which caused variation in the vertical concentration of dissolved oxygen. The halocline was mainly observed in the deep downstream regions of Saemangeum Lake that are close to the open sea. In contrast, the shallower regions upstream, which are under the influence of pollutant-loading from upstream rivers, exhibited high concentrations of chemical oxygen demand, total phosphorus, and Chl-a,resulting in lower water quality than the downstream regions. Laboratory experiments investigating the release of phosphorus at five representative locations showed that the upstream release flux, where the halocline was weaker, was higher than that downstream, where the initial level of phosphorus sedimentation was high. In particular, a need for an accurate evaluation method for the release of phosphorus at each site was suggested as slight differences were obtained depending on the estimation method used at each representative location. The results of the phosphorus release experiments led to the use of time-weighted integration(TWI), terminated time evaluation, and statistical mean value; the Environmental Fluid Dynamics Code-National Institute of Environment Research model, a widely used water quality model for studying retention watersheds, was applied to the simulation of hydraulic and water quality characteristics for the Saemangeum Lake and its surrounding waters. The result of the water quality simulation indicated the highest reproducibility for release-time TWI so that TWI values were more useful in predicting phosphorus concentrations and the subsequent management of water quality.

关键词： Eutrophication Phosphorus release Salinity Sediments Water quality simulation Environmental Fluid Dynamics Code–National Institute of Environment Research model (EFDC-NIER)

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Enabling built-in electric fields on rhenium-vacancy-rich heterojunction interfaces of transition-metal dichalcogenides for pH-universal efficient hydrogen and electric energy generation

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Carbon Energy 2024年第9期6卷 195-209页

作者： Benzhi Wang Lixia Wang Ji hoon Lee Tayirjan Taylor Isimjan Hyung Mo jeong Xiulin Yang Guangxi Key Laboratory of Low Carbon Energy Materials School of Chemistry and Pharmaceutical SciencesGuangxi Normal UniversityGuilinChina Department of Smart Fab.Technology School of Mechanical EngineeringSungkyunkwan UniversitySuwonRepublic of Korea School of Materials Science and Engineering Kyungpook National UniversityDaeguRepublic of Korea Saudi Arabia Basic Industries Corporation(SABIC)at King Abdullah University of Science and Technology(KAUST) ThuwalSaudi Arabia

Most advanced hydrogen evolution reaction(HER)catalysts show high activity under alkaline ***,the performance deteriorates at a natural and acidic pH,which is often problematic in practical ***,a rhenium(Re)sulfide–transition-metal dichalcogenide heterojunc-tion catalyst with Re-rich vacancies(NiS_(2)-ReS_(2)-V)has been *** optimized catalyst shows extraordinary electrocatalytic HER performance over a wide range of pH,with ultralow overpotentials of 42,85,and 122 mV under alkaline,acidic,and neutral conditions,***,the two-electrode system with NiS_(2)-ReS_(2)-V1 as the cathode provides a voltage of 1.73 V at 500 mA cm^(-2),superior to industrial ***,the open-circuit voltage of a single Zn–H_(2)O cell with NiS_(2)-ReS_(2)-V1 as the cathode can reach an impressive 90.9% of the theoretical value,with a maximum power density of up to 31.6 mW cm^(-2).Moreover,it shows remarkable stability,with sustained discharge for approximately 120 h at 10 mA cm^(-2),significantly outperforming commercial Pt/C catalysts under the same conditions in all aspects.A series of systematic characterizations and theoretical calculations demonstrate that Re vacancies on the heterojunction interface would generate a stronger built-in electric field,which profoundly affects surface charge distribution and subsequently enhances HER performance.

关键词： built-in electric field electrocatalysts hydrogen evolution reaction self-powered system water splitting Zn-H_(2)O cell

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Effects of granulation process variables on the physical properties of dosage forms by combination of experimental design and principal component analysis

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Asian Journal of Pharmaceutical Sciences 2019年第3期14卷 287-304页

作者： Prakash Thapa Du Hyung Choi Min Soo Kim Seong hoon jeong College of Pharmacy Dongguk UniversityGyeonggi10326Republic of Korea Department of Pharmaceutical Engineering Inje UniversityGyeongnam50834Republic of Korea College of Pharmacy Pusan National UniversityBusan46241Republic of Korea

The current study was to understand how process variables of high shear wet granulations affect physical properties of granules and tablets. The knowledge gained was intended to be used for Quality-by-Design based process design and optimization. The variables were selected based on the risk assessment as impeller speed, liquid addition rate, and wet massing time. Formulation compositions were kept constant to minimize their influence on granules properties. Multiple linear regression models were built providing understanding of the impact of each variable on granule hardness, Carr’s index, tablet tensile strength, surface mean diameter of granules, and compression behavior. The experimental results showed that the impact of impeller speed was more dominant compared to wet massing time and water addition rate. The results also revealed that quality of granules and tablets could be optimized by adjusting specific process variables(impeller speed 1193 rpm, water spray rate 3.7 ml/min, and wet massing time 2.84 min). Overall desirability was 0.84 suggesting that the response values were closer to the target one. The SEM image of granules showed that spherical and smooth granules produced at higher impeller speed, whereas rough and irregular shape granules at lower speed. Moreover, multivariate data analysis demonstrated that impeller speed and massing time had strong correlation with the granule and tablet properties. In overall, the combined experimental design and principal component analysis approach allowed to better understand the correlation between process variables and granules and tablet attributes.

关键词： Experimental design Principal component analysis High shear granulation Process parameter

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Rumex acetosella Inhibits Platelet Function via Impaired MAPK and Phosphoinositide 3-Kinase Signaling

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Chinese Journal of Integrative Medicine 2022年第9期28卷 802-808页

作者： Bo-Ra Jeon Muhammad Irfan Seung Eun Lee jeong hoon Lee Man Hee Rhee Laboratory of Physiology and Cell Signaling College of Veterinary MedicineKyungpook National UniversityDaegu41566Republic of Korea Department of Herbal Crop Research National Institute of Horticultural and Herbal Science(NIHHS)Eumseong27709Republic of Korea

Objective:To examine the antiplatelet and antithrombotic activity of Rumex acetosella ***:Standard light aggregometry was used for platelet aggregation,intracellular calcium mobilization assessed using Fura-2/AM,granule secretion(ATP release)by luminometer,and fibrinogen binding to integrin α_(Ⅱb)β_(3) detected using flow *** blotting is carried out to determine the phosphorylation of mitogen-activated protein kinase(MAPK)and phosphoinositide 3-kinase(PI3K)/Akt ***:Rumex acetosella displayed the ability to inhibit platelet aggregation,calcium mobilization,granule secretion,and fibrinogen binding to integrin α_(Ⅱb)β_(3).Rumex acetosella has also down-regulated MAPK and PI3K/Akt phosphorylation(all P<0.01).Conclusion:Rumex acetosella extract exhibits antiplatelet activity via modulating GPVI signaling,and it may protect against the development of platelet-related cardiovascular diseases.

关键词： antiplatelet ethnomedicine integrinα_(Ⅱb)β_(3) mitogen-activated protein kinase Rumex acetosella L.

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Ternary layered double hydroxide oxygen evolution reaction electrocatalyst for anion exchange membrane alkaline seawater electrolysis

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Journal of Energy Chemistry 2022年第12期75卷 127-134,I0004页

作者： Yoo Sei Park Jae-Yeop jeong Myeong Je Jang Chae-Yeon Kwon Geul Han Kim Jaehoon jeong Ji-hoon Lee Jooyoung Lee Sung Mook Choi Department of Hydrogen Energy Materials Surface&Nano Materials DivisionKorea Institute of Materials Science(KIMS)Changwon 51508Republic of Korea Department of Advanced Material Engineering Chungbuk National University1 Chungdae-roSeowon-guCheongjuChungbuk 28644Republic of Korea Department of Chemical Engineering University of WaterlooWaterlooOntario N2L 3G1 Canada School of Materials Science and Engineering Gyeongsang National UniversityJinju 52828Republic of Korea Department of Materials Science and Engineering Pusan National UniversityBusan 46241Republic of Korea Energy Industry Support Center Daegu Mechatronics&Materials InstituteDaegu 42704Republic of Korea Advanced Materials Engineering University of Science and Technology(UST)Yuseong-guDaejeon 34113Republic of Korea

Anion exchange membrane(AEM)water electrolyzers are promising energy devices for the production of clean hydrogen from ***,the lack of active and robust electrocatalysts for the oxygen evolution reaction(OER)severely impedes the development of this *** this study,a ternary layered double hydroxide(LDH)OER electrocatalyst(NiFeCo-LDH)is developed for high-performance AEM alkaline seawater *** AEM alkaline seawater electrolyzer catalyzed by the NiFeCo LDH shows high seawater electrolysis performance(0.84 A/cm^(2)at 1.7 Vcell)and high hydrogen production efficiency(77.6%at 0.5 A/cm^(2)),thus outperforming an electrolyzer catalyzed by a benchmark IrO_(2)*** NiFeCo-LDH electrocatalyst greatly improves the kinetics of the AEM alkaline seawater electrolyzer,consequently reducing its activation loss and leading to high *** on the results,this NiFeCo-LDH-catalyzed AEM alkaline seawater electrolyzer can likely surpass the energy conversion targets of the US Department of Energy.

关键词： Anion exchange membranes water electrolysis Oxygen evolution reactions Alkaline seawater electrolysis Hydrogen production

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Numerical simulation for dendrite growth in directional solidification using LBM-CA(cellular automata)coupled method

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Journal of Materials Science & Technology 2020年第14期47卷 15-24页

作者： Wonjoo Lee Yuhyeong jeong Jae-Wook Lee Howon Lee Seong-hoon Kang Young-Min Kim Jonghun Yoon Department of Mechanical Design Engineering Hanyang University222Wangsimni-roSeongdong-guSeoul 04763Republic of Korea Materials Deformation Department Korea Institute of Materials Science797 ChangwondaeroSeongsan-guChangwon-siGyeongnam-do 51508Republic of Korea Department of Mechanical Engineering Hanyang University55 Hanyangdaehak-roSangnok-guAnsan-siGyeonggi-do 15588Republic of Korea

To predict the dendrite morphology and microstructure evolution in the solidification of molten metal,numerically,lattice Boltzmann method(LBM)-cellular automata(CA)model has been developed by integrating the LBM to solve the mass transport by diffusion and convection during solidification and the CA to determine the phase transformation with respect to the solid fraction based on the local equilibrium *** is successfully validated with analytic solutions such as Lipton-Glicksman-Kurz(LGK)model in static melt,and Oseen-Ivantsov solution under the fluid flow conditions in terms of tip radius and velocity of the dendrite *** proposed LBM-CA model does not only describe different types of dendrite formations with respect to various solidification conditions such as temperature gradient and growth rate,but also predict the primary dendrite arm spacing(PDAS)and the secondary dendrite arm spacing(SDAS),quantitatively,in directional solidification(DS)experiment with Ni-based superalloy.

关键词： Cellular automata(CA) Lattice Boltzmann method(LBM) Dendritic growth Directional solidification

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Selective laser melting of Fe-Ni-Cr layer on AISI H13 tool steel

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中国有色金属学会会刊：英文版 2009年第4期19卷 921-924页

作者： byeong-Don JOO jeong-Hwan JANG Jae-Ho LEE Young-Myung SON Young-hoon MOON School of Mechanical Engineering Pusan National University

An attempt to fabricate Fe-Ni-Cr coating on AISI H13 tool steel was performed with selective laser ***-Ni-Cr coating was produced by experimental facilities consisting of a 200 W fiber laser which can be focused to 80 μm and atmospheric chamber which can control atmospheric pressure with N2 or *** layer was fabricated with various process parameters such as laser power,scan rate and fill *** quality and coating thickness were measured and *** different surface patterns,such as typeⅠ,typeⅡand type Ⅲ,are shown with various test conditions and smooth regular pattern is obtained under the conditions as 10 μm of fill spacing,50-350 mm/s of scan rate and 40 μm of fill spacing,10-150 mm/s of scan *** maximum coating thickness is increased with power elevation or scan rate drop,and average thickness of 10 μm fill spacing is lower than that of 40 μm fill spacing.

关键词：镍铬涂层工具钢激光熔融社会扫描速度铁涂层厚度光纤激光器

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Effect of Laser Parameters on Sintered Powder Morphology

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Journal of Materials Science & Technology 2010年第4期26卷 375-378页

作者： byeong-Don Joo jeong-Hwan Jang Jae-Ho Lee Young-Myung Son Young-hoon Moon Engineering Research Center for Net Shape and Die Manufacturing School of Mechanical EngineeringPusan National University

Selective laser sintering is a kind of rapid prototyping process whereby a three-dimensional part is built layerwise by laser scanning a powder. This process is highly inffuenced by powder and laser parameters such as laser power, scan rate, spot size and layer thickness. Therefore a study on fabricating a line with Fe-Ni-Cr powder on AISI H13 tool steel has been performed by selective laser sintering. In this study, fabrication was performed by experimental facilities consisting of a 200W fiber laser which can be focused to 0.08 mm and atmospheric chamber which can control atmospheric pressure with argon. The line was fabricated with various laser power, scan rate and layer thickness. Line width and surface quality were investigated. With power increase or layer thickness decrease, line width was decreased and line surface quality was improved with scan rate optimization.

关键词： Selective laser sintering Direct fabrication Fiber laser

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Surface characteristics of HA coated Ti-Hf binary alloys after nanotube formation

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中国有色金属学会会刊：英文版 2009年第4期19卷 852-856页

作者： Yong-hoon jeong Won-Gi KIM Geun-Hyeong PARK Han-Cheol CHOE Yeong-Mu KO Department of Dental Materials & Research Center of Nano-Interface Activation for Biomaterials College of DentistryChosun University Research Center for Oral Disease Regulation of the Aged College of DentistryChosun University

Ti-Hf binary alloys contained 10%,20%,30% and 40%(mass fraction)Hf were manufactured in the vacuum furnace *** then,specimens were homogenized for 24 h at 1 000 ℃ in argon *** formation of oxide nanotubes was conducted by anodic oxidation on the Ti-Hf alloy in 1 mol/L H3PO4 electrolytes containing small amounts of NaF at room *** hydroxyapatite(HA) coating made of tooth ash prepared by electron-beam physical vapor deposition(EB-PVD) *** corrosion behaviors of the specimens were examined through potentiodynamic test in 0.9% NaCl solution by *** microstructures of the alloys were examined by field emission scanning electron microscopy(FE-SEM) and x-ray diffractometer(XRD).It was observed that the lamellar structure translated to needle-like structure with Hf *** formed and HA coated Ti-xHf alloys had a good corrosion resistance.

关键词：二元合金 HA涂层纳米管表面特性管形 0.9%NaCl溶液物理气相沉积铪

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Application of direct laser metal tooling for AISI H13 tool stee

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中国有色金属学会会刊：英文版 2009年第B09期19卷 284-287页

作者： Jae-Ho LEE jeong-Hwan JANG byeong-Don JOO Hong-Sup YIM Young-hoon MOON School of Mechanical Engineering Pusan National University

In the die industry, it is commonly agreed that residual tool life can be successfully extended by timely repair of damaged surfaces. Traditionally, the main repair process is tungsten inert gas (TIG) welding, but a new process called direct laser metal tooling (DLMT) emerges. DLMT is a manual process, of which results depend on the materials of the powders and tools, the laser process and parameters. This technology is a direct-metal freeform fabrication technique in which a 200 W fiber laser is used. AISI H13 tool steel is a suitable material for die casting tools because of the high resistance to thermal fatigue and dimensional stability. In this research, AISI H13 tool steel was melted with metal powder by fiber laser. Before melting AISI H13, the powders were analyzed with XRF equipment. Then, hardness distribution of laser melted zone was investigated. The microstructure in laser melted zone was discussed. In order to identify the effect of particle size of powder on the melted zone, two types of particle sizes of powders were used. Experimental results show that the mold repair process using DLMT can be applied in the mold repair industry.

关键词：金属模具应用激光工具钢 H13 社会光纤激光器粉末材料修复过程

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