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Oxygen vacancy engineering for tuning the catalytic activity of LaCoO_(3) perovskite

Journal of Rare Earths 2024年第3期42卷 506-514,I0003页

作者： Jeong hyun Cho Minjae Kim Inchan Yang Kyung tae park Chang Houn Rhee Hai Woong park Ji Chul Jung Department of Chemical Engineering Myongji UniversityYongin 17058Republic of Korea Institute of Advanced Composite Materials Korea Institute of Science and TechnologyWanju-gunJeollabuk-do 55324Republic of Korea Iron&Steel Process Engineering Research Group POSCOPohang 37859Republic of Korea Hydrogen Research Center Research Institute of Industrial Science&Technology(RIST)Pohang 37673Republic of Korea

Herein, we attempted to engineer oxygen vacancies on the surface of LaCoO_(3) perovskite through simple post-treatments(acid or reductive thermal treatments). Acid treatment induces oxygen vacancies through the selective etching of the La cations, whereas thermal treatment in a reducing atmosphere generates oxygen vacancies by directly removing lattice oxygen. The characterization results confirm that the number of surface oxygen vacancies, which are crucial in various catalytic oxidation reactions,considerably increases in the LaCoO_(3) catalysts treated with acid or reducing gas. Acid treatment enriches the oxygen vacancies while maintaining the structure of the LaCoO_(3) catalysts, which can not be achieved through reductive thermal treatment. Therefore, the acid treatment is considered a promising technique for oxygen vacancy engineering of perovskite catalysts for tuning their catalytic activities. Furthermore,the catalytic activities of the posttreated LaCoO_(3) catalysts for CO oxidation were evaluated and are noted to be considerably better than those of the pristine LaCoO_(3) catalyst due to their abundant oxygen vacancies. Consequently, we conclude that the oxygen vacancies of perovskite catalysts can be effectively engineered via two simple methods and play a significant role in CO oxidation.

关键词： LaCoO_(3)perovskite Acid treatment Reductive thermal treatment Oxygen vacancy CO oxidation Rare earths

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M1-polarized macrophage-derived cellular nanovesicle-coated lipid nanoparticles for enhanced cancer treatment through hybridization of gene therapy and cancer immunotherapy

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Acta Pharmaceutica Sinica B 2024年第7期14卷 3169-3183页

作者： Ha Eun Shin Jun-Hyeok Han Seungyong Shin Ga-hyun Bae Boram Son tae-hyung Kim Hee Ho park Chun Gwon park Wooram park Department of Integrative Biotechnology Sungkyunkwan University(SKKU)SuwonGyeonggi 16419Republic of Korea Deparment of Inteligent Precision Healthcare Convergence SKKUSuwonGyeonggi 16419Republic of Korea Department of MetaBioHealth SKKU Institute for ConvergenceSKKUSuwonGyeonggi 16419Republic of Korea Department of Bioengineering Hanyang UniversitySeoul 04763Republic of Korea Department of Integrative Engineering Chung-Ang UniversitySeoul 06974Republic of Korea Department of Biomedical Engineering SKKUSuwonGyeonggi 16419Republic of Korea Korea Institute of Science and Technology(KIST) Seoul 02792Republic of Korea

Optimum genetic delivery for modulating target genes to diseased tissue is a major obstacle for profitable gene *** nanoparticles(LNPs),considered a prospective vehicle for nucleic acid delivery,have demonstrated efficacy in human use during the COVID-19 *** study introduces a novel biomaterial-based platform,M1-polarized macrophage-derived cellular nanovesicle-coated LNPs(M1-C-LNPs),specifically engineered for a combined gene-immunotherapy approach against solid *** dual-function system of M1-C-LNPs encapsulates Bcl2-targeting siRNA within LNPs and immune-modulating cytokines within M1 macrophage-derived cellular nanovesicles(M1-NVs),effectively facilitating apoptosis in cancer cells without impacting T and NK cells,which activate the intratumoral immune response to promote granule-mediating killing for solid tumor *** retention within tumor was observed upon intratumoral administration of M1-C-LNPs,owing to the presence of adhesion molecules on M1-NVs,thereby contributing to superior tumor growth *** findings represent a promising strategy for the development of targeted and effective nanoparticle-based cancer genetic-immunotherapy,with significant implications for advancing biomaterial use in cancer therapeutics.

关键词： Genetic-immunotherapy M1 macrophage-derived cellular nanovesicles Lipid nanoparticles(LNPs) Gene therapy siRNA Cancer immunotherapy Solid tumor Tumor microenvironment(TME)

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Polymer waveguide tunable transceiver for photonic front-end in the 5G wireless network

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Photonics Research 2021年第2期9卷 181-186页

作者： tae-hyun park SUNG-MOON KIM EUN-SU LEE MIN-CHEOL OH Department of Electronics Engineering Pusan National UniversityPusan(Busan)46241Republic of Korea

A photonic front-end in the 5 G wireless network based on wavelength-division multiplexing optical communication requires low-cost tunable transceivers. By exploiting polymer waveguide Bragg-grating technology, we propose a tunable transceiver consisting of an external cavity tunable laser and a tilted grating tunable *** particular, a double-reflection tunable filter provides narrower reflection bandwidth and suppresses undesired mode coupling, improving the side-mode suppression ratio(SMSR) and reducing adjacent-channel crosstalk. By introducing perfluorinated polymers with low birefringence, polarization independence, which is a prerequisite for wavelength filter elements, is secured, and 20 d B bandwidth of 0.69 nm, wavelength tunability over 40 nm,and SMSR of 42 d B are achieved.

关键词： tunable waveguide network

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Zwitterion-assisted transition metal dichalcogenide nanosheets for scalable and biocompatible inkjet printing

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Nano Research 2020年第10期13卷 2726-2734页

作者： Hyeokjung Lee Min Koo Chanho park Madhumita Patel Hyowon Han tae hyun park Pawan Kumar Won-Gun Koh Cheolmin park Department of Materials Science and Engineering Yonsei University Seoul 03722Republic of Korea Department of Chemical and Biomolecular Engineering Yonsei UniversitySeoul 03722Republic of Korea

Inkjet printing of two-dimensional(2D)transition metal dichalcogenide(TMD)nanosheets fabricated by liquid-phase exfoliation(LPE)allows simple,mass-producible,and low-cost photo-electronic *** LPE processes involve toxic and environmentally hazardous solvents;however,dispersants have restricted the extent of applications of 2D-TMD ***,various 2D-TMD nanosheets,including MoS2,MoSe2,WS2,and WSe2,in addition to few-layered graphene,are inkjet-printed using a LPE process based on zwitterionic dispersants in *** with cationic and anionic species are water-soluble,while alkyl chain moieties associated with two ionic species adhere universally on the surface of TMD nanosheets,resulting in high throughput liquid exfoliation of the *** zwitterion-assisted TMD nanosheets in water are successtully employed as an ink without the need for additives to adjust the viscosity and surface tension of the ink for use in an office inkjet printer;this gives rise to A4 scale,large-area inkjet-printed images on diverse substrates,such as metals,oxides,and polymer substrates patchable onto human *** with conductive graphene nanosheet inks allowed the development of mechanically flexible,biocompatible-printed arrays of photodetectors with pixelated MoSe2 channels on a paper exhibiting a photocurrent ON/OFF ratio of approximately 1038 and photocurrent switching of 500 ms.

关键词： transition metal dichalcogenide nanosheets zwitterions zwitterion-assisted liquid-phase exfoliation scalable inkjet printing biocompatible

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Effect of hafnium and molybdenum addition on inclusion characteristics in Co-based dual-phase high-entropy alloys

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1639-1650页

作者： Yong Wang Wei Wang Joo hyun park Wangzhong Mu Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education&Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081China Department of Materials Science and Engineering KTH Royal Institute of TechnologySE-10044StockholmSweden Department of Chemical Engineering Northeast Electric Power UniversityJilin 132012China Department of Materials Science and Chemical Engineering Hanyang UniversityAnsan 15588Korea Engineering Materials Division of Materials ScienceDepartment of Engineering Science and MathematicsLuleå University of Technology97187 LuleåSweden

Specific grades of high-entropy alloys(HEAs)can provide opportunities for optimizing properties toward high-temperature *** this work,the Co-based HEA with a chemical composition of Co_(47.5)Cr_(30)Fe_(7.5)Mn_(7.5)Ni_(7.5)(at%)was *** refractory metallic elements hafnium(Hf)and molybdenum(Mo)were added in small amounts(1.5at%)because of their well-known positive effects on high-temperature *** characteristics were comprehensively explored by using a two-dimensional cross-sectional method and extracted by using a three-dimensional electrolytic extraction *** results revealed that the addition of Hf can reduce Al_(2)O_(3)inclusions and lead to the formation of more stable Hf-rich inclusions as the main *** addition cannot influence the inclusion type but could influence the inclusion characteristics by affecting the physical parameters of the HEA *** calculated coagulation coefficient and collision rate of Al_(2)O_(3)inclusions were higher than those of HfO_(2)inclusions,but the inclusion amount played a larger role in the agglomeration behavior of HfO_(2)and Al_(2)O_(3)*** impurity level and active elements in HEAs were the crucial factors affecting inclusion formation.

关键词： high-entropy alloy non-metallic inclusion agglomeration thermodynamics alloying

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Depolarization mitigated in ferroelectric Hf_(0.5)Zr_(0.5)O_(2)ultrathin films(<5 nm)on Si substrate by interface engineering

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Journal of Advanced Ceramics 2024年第3期13卷 282-292页

作者： Se hyun Kim Younghwan Lee Dong hyun Lee Geun Hyeong park hyun Woo Jeong Kun Yang Yong Hyeon Cho Young Yong Kim Min Hyuk park Department of Materials Science and Engineering College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Research Institute of Advanced Materials College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Inter-university Semiconductor Research Center College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Pohang Accelerator Laboratory Pohang University of Science&TechnologyPohang 790784Republic of Korea

(Hf,Zr)O_(2)offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the ***,scaling this material to sub-5 nm thickness poses several challenges,including the formation of an interfacial layer and high trap *** particular,a low-k SiO_(2)interfacial layer is naturally formed when(Hf,Zr)O_(2)films are directly grown on a Si substrate,leading to high depolarization fields and rapid reduction of the remanent *** address these issues,we conducted a study to significantly improve ferroelectricity and switching endurance of(Hf,Zr)O_(2)films with sub-5 nm thicknesses by inserting a TiO_(2)interfacial *** deposition of a Ti film prior to Hf_(0.5)Zr_(0.5)O_(2)film deposition resulted in a high-k TiO_(2)interfacial layer and prevented the direct contact of Hf_(0.5)Zr_(0.5)O_(2)with *** findings show that the high-k TiO_(2)interfacial layer can reduce the SiO_(2)/Si interface trap density and the depolarization field,resulting in a switchable polarization of 60.2μC/cm^(2)for a 5 nm thick Hf_(0.5)Zr_(0.5)O_(2)***,we propose that inserting a high-k TiO_(2)interfacial layer between the Hf_(0.5)Zr_(0.5)O_(2)film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of(Hf,Zr)O_(2)grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.

关键词： ferroelectric charge trapping hafnia depolarization

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Extracellular vesicles for neural regeneration after spinal cord injury

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Neural Regeneration Research 2024年第3期19卷 491-492页

作者： Young-Ju Lim Wook-tae park Gun Woo Lee Department of Orthopedic Surgery Yeungnam University Medical CenterYeungnam University College of MedicineDaeguKorea

What is spinal cord injury:Spinal cord injury(SCI)is the damage to the structure of the bundles of cells and nerves that communicate signals from the brain to the body and *** pathology of SCI includes both primary and secondary injuries(Morales et al.,2016).Physical forces such as compression,shearing,contusion,and tearing are major causes of primary injury in *** are two main processes in primary injury:acute and *** acute phase includes traumatic disruption of axons and hemorrhage of the blood vessels around the spinal *** injury to the vessels can lead to increased edema within the neural and cord tissues,susceptibility to infiltration by microglia and astrocytes,excitotoxicity,and ***,disruption of the blood-spinal cord barrier results in the release of inflammatory cytokines from specific cells and vessels.

关键词： acute injuries nerves

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Tidal effects based on a GUP-induced effective metric

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Communications in Theoretical Physics 2024年第9期76卷 65-74页

作者： Soon-tae Hong Yong-Wan Kim Young-Jai park Center for Quantum Spacetime and Department of Physics Sogang University Department of Physics and Research Institute of Physics and Chemistry Jeonbuk National University Department of Physics Sogang University

In this paper, we study tidal forces in the Schwarzschild black hole, whose metric explicitly includes a generalized uncertainty principle(GUP) effect. We also investigate interesting features of the geodesic equations and tidal effects that are dependent on the GUP parameter αrelated to a minimum length. Then, by solving the geodesic deviation equations explicitly with appropriate boundary conditions, we show that α in the effective metric affects both the radial and angular components of the geodesic equation, particularly near the singularities.

关键词： effective metric generalized uncertainty principle geodesic deviation equation

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Evolution of nonmetallic inclusions in 80-t 9CrMoCoB large-scale ingots during electroslag remelting process

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1525-1539页

作者： Shengchao Duan Min Joo Lee Yao Su Wangzhong Mu Dong Soo Kim Joo hyun park School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China Department of Materials Science and Chemical Engineering Hanyang UniversityAnsan 15588Rep.of Korea Department of Materials Science and Engineering KTH Royal Institute of TechnologyBrinellvägen 23Stockholm 10044Sweden Department of Engineering Science and Mathematics Division of Materials ScienceLuleåUniversity of Technology97187 LuleåSweden Casting&Forging Business Unit Nuclear Business GroupDoosan EnerbilityChangwon 51711Rep.of Korea

In combination with theoretical calculations,experiments were conducted to investigate the evolution behavior of nonmetallic inclusions(NMIs)during the manufacture of large-scale heat-resistant steel ingots using 9CrMoCoB heat-resistant steel and CaF_(2)–CaO–Al_(2)O_(3)–SiO_(2)–B_(2)O_(3)electroslag remelting(ESR)-type slag in an 80-t industrial ESR *** main types of NMI in the consumable electrode comprised pure alumina,a multiphase oxide consisting of an Al_(2)O_(3)core and liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO shell,and M_(23)C_(6)carbides with an MnS *** Al_(2)O_(3)and MnS inclusions had higher precipitation temperatures than the M_(23)C_(6)-type carbide under equilibrium and nonequilibrium solidification ***,inclusions can act as nucleation sites for carbide layer *** ESR process completely removed the liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO oxide and MnS inclusion with a carbide shell,and only the Al_(2)O_(3)inclusions and Al_(2)O_(3)core with a carbide shell occupied the remelted *** M_(23)C_(6)-type carbides in steel were determined as Cr_(23)C_(6)based on the analysis of transmission electron microscopy *** substitution of Cr with W,Fe,or/and Mo in the Cr_(23)C_(6)lattice caused slight changes in the lattice parameter of the Cr_(23)C_(6)***,Cr_(21.34)Fe_(1.66)C_(6),(Cr_(19)W_(4)C_(6),Cr_(18.4)Mo_(4.6)C_(6),and Cr_(16)Fe_(5)Mo_(2)C_(6)can match the fraction pattern of Cr_(23)C_(6)*** Al_(2)O_(3)inclusions in the remelted ingot formed due to the reduction of CaO,SiO_(2),and MnO components in the liquid *** increased Al content in liquid steel or the higher supersaturation degree of Al_(2)O_(3)precipitation in the remelted ingot than that in the electrode can be attributed to the evaporation of CaF_(2)and the increase in CaO content in the ESR-type slag.

关键词： nonmetallic inclusion heat-resistant steel electroslag remelting M_(23)C_(6) carbide MnS inclusion supersaturation degree

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Body-Shaping Membrane to Regenerate Breast Fat by Elastic Structural Holding

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Research 2024年第1期2023卷 165-180页

作者： Hye-Seon Kim Jeongeun park hyun-Su Ha Sewoom Baek Chan Hee Lee Kyubae Lee Suji park Jueun Kim Se Won Yi Hak-Joon Sung Department of Medical Engineering Graduate School of Medical ScienceBrain Korea 21 ProjectYonsei University College of MedicineSeoul 03722Republic of Korea TMD LAB Co.Ltd. 6th Floor31Gwangnaru-ro 8-gilSeongdong-guSeoul 04799Republic of Korea

Tissue regeneration requires structural holding and movement support using tissue-type-specific aids such as bone casts,skin bandages,and joint ***,an unmet need exists in aiding breast fat regeneration as the breast moves following continuous body motion by exposing the breast fat to dynamic ***,the concept of elastic structural holding is applied to develop a shape-fitting moldable membrane for breast fat regeneration(“adipoconductive”)after surgical defects are *** membrane has the following key characteristics:(a)It contains a panel of honeycomb structures,thereby efficiently handling motion stress through the entire membrane;(b)a strut is added into each honeycomb in a direction perpendicular to gravity,thereby suppressing the deformation and stress concentration upon lying and standing;and(c)thermo-responsive moldable elastomers are used to support structural holding by suppressing large deviations of movement that occur *** elastomer became moldable upon a temperature shift above T_(m).The structure can then be fixed as the temperature *** a result,the membrane promotes adipogenesis by activating mechanotransduction in a fat miniature model with pre-adipocyte spheroids under continuous shaking in vitro and in a subcutaneous implant placed on the motion-prone back areas of rodents in vivo.

关键词： thereby shaking Elastic

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