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Numerical study on the performance of nozzle flow for supersonic chemical oxygen-iodine lasers

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Acta Mechanica Sinica 2008年第2期24卷 133-142页

作者： Zongmin Hu Junming Lā Zonglin Jiang rho-shin myong Tae-Hwan Cho LHD Institute of MechanicsCAS Beijing 100080 China Research Center for Aircraft Parts Technology Geyongsang National University Jinju 660-701 South Korea

Laser performance is greatly dependent on its operating conditions due to the strong coupling among multi- physics such as gas-dynamics, chemical reaction kinetics and optics in the mixing nozzle of COIL. In this paper, 3D CFD technology is used to simulate the mixing and reactive flow of subsonic cross jet scheme at different conditions. Results obtained show that the jet penetration depth plays a dominant role in the spatial distribution of small signal gains. In the case of over-penetration, unsteady flow structures are induced by impinging between the opposing jets. The optimum spatial distribution of the chemical performance cannot be obtained even if the full penetration condition is achieved through the subsonic transverse jet mixing scheme in the COIL nozzle flow.

关键词： Chemical oxygen-iodine laser (COIL) Numerical simulation Small signal gains Unsteady structures

Pulsed laser interference patterning of transition-metal carbides for stable alkaline water electrolysis kinetics

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Carbon Energy 2024年第5期6卷 65-80页

作者： Yewon Oh Jayaraman Theerthagiri Ahreum Min Cheol Joo Moon Yiseul Yu myong Yong Choi Department of Chemistry(BK21 FOUR) Research Institute of Natural SciencesGyeongsang National UniversityJinjuRepublic of Korea Core−Facility Center for Photochemistry and Nanomaterials Gyeongsang National UniversityJinjuRepublic of Korea

We investigated the role of metal atomization and solvent decomposition into reductive species and carbon clusters in the phase formation of transition-metal carbides(TMCs;namely,Co_(3)C,Fe_(3)C,TiC,and MoC)by pulsed laser ablation of Co,Fe,Ti,and Mo metals in *** interaction between carbon s-p-orbitals and metal d-orbitals causes a redistribution of valence structure through charge transfer,leading to the formation of surface defects as observed by X-ray photoelectron *** defects influence the evolved TMCs,making them effective for hydrogen and oxygen evolution reactions(HER and OER)in an alkaline ***_(3)C with more oxygen affinity promoted CoO(OH)intermediates,and the electrochemical surface oxidation to Co_(3)O_(4)was captured via in situ/operando electrochemical Raman probes,increasing the number of active sites for OER *** with more d-vacancies exhibits strong hydrogen binding,promoting HER kinetics,whereas Fe_(3)C and TiC with more defect states to trap charge carriers may hinder both OER and HER *** results show that the assembled membrane-less electrolyzer with Co_(3)C∥Co_(3)C and MoC∥MoC electrodes requires~2.01 and 1.99 V,respectively,to deliver a 10 mA cm−2 with excellent electrochemical and structural *** addition,the ascertained pulsed laser synthesis mechanism and unit-cell packing relations will open up sustainable pathways for obtaining highly stable electrocatalysts for electrolyzers.

关键词： acetone H_(2)and O_(2)evolution reactions pulsed laser ablation surface defects transition-metal carbides water electrolyzer

Sustainable Furfural Biomass Feedstocks Electrooxidation toward Value-Added Furoic Acid with Energy-Saving H_(2) Fuel Production Using Pt-Decorated Co_(3)O_(4) Nanospheres

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Energy & Environmental Materials 2024年第2期7卷 350-358页

作者： Talshyn Begildayeνa Jayaraman Theerthagiri Seung Jun Lee Ahreum Min Gyeong-Ah Kim Siνakumar Manickam myong Yong Choi Department of Chemistry(BK21 FOUR) Core-Facility Center for Photochemistry&NanomaterialsResearch Institute of Natural SciencesGyeongsang National UniversityJinju 52828South Korea Petroleum and Chemical Engineering Faculty of EngineeringUniversiti Teknologi BruneiJalan Tungku Link GadongBandar Seri Begawan BE1410Brunei Darussalam

Here,furfural oxidation was performed to replace the kinetically sluggish O_(2)evolution reaction(OER).Pt-Co_(3)O_(4)nanospheres were developed via pulsed laser ablation in liquid(PLAL)in a single step for the paired electrocatalysis of an H_(2)evolution reaction(HER)and furfural oxidation reaction(FOR).The FOR afforded a high furfural conversion(44.2%)with a major product of 2-furoic acid after a 2-h electrolysis at 1.55 V versus reversible hydrogen electrode in a 1.0-M KOH/50-mM furfural *** Pt-Co_(3)O_(4)electrode exhibited a small overpotential of 290 mV at 10 mA cm^(-2).As an anode and cathode in an electrolyzer system,the Pt-Co_(3)O_(4)electrocatalyst required only a small applied cell voltage of~1.83 V to deliver 10 mA cm^(-2),compared with that of the pure water electrolyzer(OER||HER,~1.99 V).This study simultaneously realized the integrated production of energy-saving H_(2)fuel at the cathode and 2-furoic acid at the anode.

关键词： biomass conversion electrochemical furfural oxidation overall water splitting Pt-Co_(3)O_(4)electrocatalyst pulsed laser ablation in liquid

Electrokinetic-mechanism of water and furfural oxidation on pulsed laser-interlaced Cu_(2)O and CoO on nickel foam

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Journal of Energy Chemistry 2024年第4期91卷 145-154页

作者： Yewon Oh Jayaraman Theerthagiri M.L.Aruna Kumari Ahreum Min Cheol Joo Moon myong Yong Choi Department of Chemistry(BK21 FOUR) Research Institute of Natural SciencesGyeongsang National UniversityJinju 52828Republic of Korea Department of Chemistry The Oxford College of ScienceBengaluruKarnataka 560102India Core-Facility Center for Photochemistry&Nanomaterials Gyeongsang National UniversityJinju 52828Republic of Korea

The electrocatalytic oxidation of biomass-derived furfural(FF)feedstocks into 2-furoic acid(FA)holds immense industrial potential in optics,cosmetics,polymers,and ***,we fabricated Co O/Ni O/nickel foam(NF)and Cu_(2)O/Ni O/NF electrodes via in situ pulsed laser irradiation in liquids(PLIL)for the bifunctional electrocatalysis of oxygen evolution reaction(OER)and furfural oxidation reaction(FOR),*** oxidation of NF surface to NiO and deposition of CoO and/or Cu_(2)O on NF during PLIL offer distinct advantages for enhancing both the OER and ***/NiO/NF electrocatalyst provides a consistently low overpotential of~359 m V(OER)at 10 m A/cm^(2),achieving the maximum FA yield(~16.37 m M)with 61.5%selectivity,79.5%carbon balance,and a remarkable Faradaic efficiency of~90.1%during 2 h of FOR at 1.43 V(*** hydrogen electrode).Mechanistic pathway via in situ electrochemical-Raman spectroscopy on CoO/NiO/NF reveals the involvement of phase transition intermediates(NiOOH and CoOOH)as surface-active centers during electrochemical *** carbonyl carbon in FF is attacked by hydroxyl groups to form unstable hydrates that subsequently undergo further oxidation to yield FA *** method holds promise for large-scale applications,enabling simultaneous production of renewable building materials and fuel.

关键词： Pulsed laser irradiation in liquids Water and furfural oxidation In situ Raman spectroscopy CoO/NiO/nickel foam Cu_(2)O/Nio/nickel foam 2-furoic acid

Galectin 3-binding protein(LGALS3BP)depletion attenuates hepatic fibrosis by reducing transforming growth factor-β1(TGF-β1)availability and inhibits hepatocarcinogenesis

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Cancer Communications 2024年第10期44卷 1106-1129页

作者： Dae-Hwan Kim Minjeong Sung myong-Suk Park Eun-Gene Sun Sumin Yoon Kyung Hyun Yoo Kamalakannan Radhakrishnan Sung Yun Jung Woo-Kyun Bae Sang-Hee Cho Ik-Joo Chung Department of Internal Medicine Division of Hematology and OncologyChonnam National University Medical SchoolHwasunSouth Korea Department of Internal Medicine Division of Hematology and OncologyChonnam National University Hwasun HospitalHwasunSouth Korea Combinatorial Tumor Immunotherapy MRC Center Chonnam National University Medical SchoolHwasunSouth Korea National Immunotherapy Innovation Center HwasunSouth Korea BioMedical Sciences Graduate Program Chonnam National UniversityHwasunSouth Korea Department of Biological Science SookmyungWomen’s UniversitySeoulSouth Korea Clinical Vaccine R&D Center Chonnam National UniversityHwasunSouth Korea Department of Biochemistry and Molecular Pharmacology Baylor College of MedicineHoustonTexasUSA

Background:Increased Galectin 3-binding protein(LGALS3BP)serum levels have been used to assess hepatic fibrosis stages and the severity of hepatocellular carcinoma(HCC).Considering the crucial role of transforming growth factor-β1(TGF-β1)in the emergence of these diseases,the present study tested the hypothesis that LGALS3BP regulates the TGF-β1 signaling ***:The expression levels of LGALS3BP and TGFB1 were analyzed in patients with metabolic dysfunction-associated steatohepatitis(MASH)and *** omics techniques,such as RNA-sequencing,transposaseaccessible chromatin-sequencing assay,and liquid chromatography-tandem mass spectrometry proteomics,were used to identify the regulatory mechanisms for the LGALS3BP-TGF-β1 *** effects of altered TGF-β1 signaling by LGALS3BP were investigated in conditional LGALS3BP-knockin and LGALS3BP-knockout ***:In patients with MASH and HCC,the levels of LGALS3BP and TGFB1 exhibited positive *** of LGALS3BP by the inflammatory cytokine interferonαin HCC cells or ectopic overexpression of LGALS3BP in hepatocytes promoted the expression levels of *** fibrosis was observed in the livers of hepatocyte-specific LGALS3BP-knockin mice,with increased TGFB1 ***3BP directly bound to and assembled integrinαV,an integral mediator required for releasing active TGF-β1 from extracellular latent complex with the rearranged F-actin *** released TGF-β1 activated JunB transcription factor,which in turn promoted the TGF-β1 positive feedback ***3BP deletion in the hepatocytes downregulated TGF-β1 signaling and CCl4 induced ***,LGALS3BP depletion hindered hepatocarcinogenesis by limiting the availability of fibrogenic TGF-β***:LGALS3BP plays a crucial role in hepatic fibrosis and carcinogenesis by controlling the TGF-β1 signaling pathway,making it a promising therapeutic target in TGF-β1-related diseases.

关键词： F-actin FAK hepatic carcinogenesis IntegrinαV Interferonα JunB LGALS3BP metabolic dysfuntion-associated steatohepatitis tensile force TGF-β1

Cloud Radiative Effects and Changes Simulated by the Coupled Model Intercomparison Project Phase 5 Models

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Advances in Atmospheric Sciences 2017年第7期34卷 859-876页

作者： Sun-Hee shin Ok-Yeon KIM Dongmin KIM myong-In LEE Climate Research Department APEC Climate Center Busan 48058 Republic of Korea School of Urban and Environmental Engineering Ulsan National Institute of Science and Technology Ulsan 44919 Republic of Korea

Using 32 CMIP5（Coupled Model Intercomparison Project Phase 5） models, this study examines the veracity in the simulation of cloud amount and their radiative effects（CREs） in the historical run driven by observed external radiative forcing for 1850-2005, and their future changes in the RCP（Representative Concentration Pathway） 4.5 scenario runs for2006-2100. Validation metrics for the historical run are designed to examine the accuracy in the representation of spatial patterns for climatological mean, and annual and interannual variations of clouds and CREs. The models show large spread in the simulation of cloud amounts, specifically in the low cloud amount. The observed relationship between cloud amount and the controlling large-scale environment are also reproduced diversely by various models. Based on the validation metrics,four models-ACCESS1.0, ACCESS1.3, Had GEM2-CC, and Had GEM2-ES-are selected as best models, and the average of the four models performs more skillfully than the multimodel ensemble *** models project global-mean SST warming at the increase of the greenhouse gases, but the magnitude varies across the simulations between 1 and 2 K, which is largely attributable to the difference in the change of cloud amount and distribution. The models that simulate more SST warming show a greater increase in the net CRE due to reduced low cloud and increased incoming shortwave radiation, particularly over the regions of marine boundary layer in the subtropics. Selected best-performing models project a significant reduction in global-mean cloud amount of about-0.99% K^-1and net radiative warming of 0.46 W m^-2K^-1, suggesting a role of positive feedback to global warming.

关键词： warming cloud radiative historical CMIP interannual greenhouse ACCESS oceans seasonal

A Remark on Leray's Problem on Stationary Navier–Stokes Flows with Large Fluxes in Infinite Cylindrical Domains

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Acta Mathematica Sinica,English Series 2015年第10期31卷 1571-1581页

作者： myong-Hwan RI Institute of Mathematics State Academy of SciencesPyongyang DPR Korea

We consider Leray＇s problem on stationary Navier Stokes flows with arbitrary large fluxes in an unbounded cylinder with several exits to infinity. For a stationary Navier Stokes flow with large fluxes in the unbounded cylinder, we prove that, if the difference between the pressure of the main flow and the pressure of the Poiseuille flow with the same flux in a branch of the cylinder remains bounded at ｜x｜→∞, then the flow behaves at infinity of the branch like the Poiseuille flow.

关键词： Leray's problem Navier-Stokes equations large flux unbounded cylindrical domains

Regularity for 3D Navier–Stokes Equations Based on Energy Distribution at Wavenumber Bands

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Acta Mathematica Sinica,English Series 2019年第8期35卷 1377-1392页

作者： myong-Hwan RI Institute of Mathematics State Academy of SciencesDPR Korea

We present some regularity criteria for the Leray–Hopf weak solutions to the Cauchy problem for 3D Navier–Stokes equations based on energy distribution at wavenumber bands. We show sufficient conditions for regularity based on the ratios of energy dissipation rates at sufficiently high wavenumber bands and neighboring medium wavenumber bands. Moreover, we give a regularity criterion based on relations between energy at high and low wavenumber bands.

关键词： Navier-Stokes equations global regularity energy transfer

MAXIMAL L^(1)-REGULARITY OF GENERATORS FOR BOUNDED ANALYTIC SEMIGROUPS IN BANACH SPACES

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Acta Mathematica Scientia 2022年第4期42卷 1261-1272页

作者： myong-Hwan RI Reinhard FARWIG Institute of Mathematics State Academy of SciencesPyongyangDPR Korea Department of Mathematics Darmstadt University of TechnologyGermany

In this paper,we prove that the generator of any bounded analytic semigroup in(θ,1)-type real interpolation of its domain and underlying Banach space has maximal L^(1)-regularity,using a duality argument combined with the result of maximal continuous *** an application,we consider maximal L^(1)-regularity of the Dirichlet-Laplacian and the Stokes operator in inhomogeneous B_(q),^(s),1-type Besov spaces on domains of R^(n),n≥2.

关键词： Maximal L^(1)-regularity sectorial operator Stokes operator