检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

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

在线全文

学校读者我要写书评

暂无评论

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

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

在线全文

学校读者我要写书评

暂无评论

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

Simple and universal function of acetic acid to overcome the drought crisis

在线全文

学校读者我要写书评

暂无评论

Stress Biology 2023年第1期3卷 158-163页

作者： Toru Kudo Taiko Kim To Jong-myong Kim Ac-Planta Inc TokyoJapan Department of Biological Sciences The University of TokyoTokyoJapan Graduate School of Agricultural and Life Sciences The University of TokyoTokyoJapan

Acetic acid is a simple and universal compound found in various ***,acetic acid was found to play an essential role in conferring tolerance to water deficit stress in *** novel mechanism of drought stress tolerance mediated by acetic acid via networks involving phytohormones,genes,and chromatin regulation has great potential for solving the global food crisis and preventing desertification caused by global *** highlight the functions of acetic acid in conferring tolerance to water deficit stress.

关键词： Acetic acid Drought Epigenetics Jasmonic acid Metabolism Tolerance Water deficit

Modulating the synergy of Pd@Pt core-shell nanodendrites for boosting methanol electrooxidation kinetics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第34期165卷 153-160页

作者： Hyeon Jeong Kim Cheol Joo Moon Seokhee Lee Jayaraman Theerthagiri Jong Wook Hong myong Yong Choi Young Wook Lee Department of Chemistry and Research Institute of Natural Sciences Gyeongsang National UniversityJinju 52828Republic of Korea Core-Facility Center for Photochemistry&Nanomaterials Gyeongsang National UniversityJinju 52828Republic of Korea Energy&Environment Division Korea Institute of Ceramic Engineering and Technology(KICET)Jinju 52851Republic of Korea Department of Chemistry University of UlsanUlsan 44610Republic of Korea Department of Education Chemistry and Research Institute of Natural Sciences Gyeongsang National UniversityJinju 52828Republic of Korea

The single-pot production of Pd@Pt core-shell structures is a promising approach as it offers large surface area,catalytic capability,and *** this work,we established a single-pot process to produce Pd@Pt core-shell nanodendrites with tunable composition,shape and size for optimal electrochemical ***@Pt nanodendrites with diverse compositions were synthesized by tuning the ratios of Pd and Pt sources in an aqueous environment using cetyltrimethylammonium chloride,which functioned as both the surfactant and the reducing agent at an elevated temperature(90°C).The synthesized Pd5@Pt5 nanodendrites showed exceptional electrochemical action toward the methanol oxidation reaction related with another compositional Pd@Pt nanodendrites and conventional Pt/C *** addition,Pd5@Pt5 nanodendrites exhibited good CO tolerance owing to their surface features and the synergistic effect among Pt and ***,nanodendrites with a Pt-rich surface provided exceptional catalytic active *** with the conventional Pt/C electrocatalyst,the anodic peak current obtained by Pd5@Pt5 nanodendrites was 3.74 and 2.18 times higher in relations of mass and electrochemical active surface area-normalized current density,*** approach offers an attractive strategy to design electrocatalysts with unique structures and outstanding catalytic performance and stability for electrochemical energy conversion.

关键词： Core-shell nanostructure Pd@Pt electrocatalysis One-pot synthesis Formation mechanism of nanodendrites Methanol oxidation reaction

Review of vortex methods for rotor aerodynamics and wake dynamics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Aerodynamics 2022年第1期4卷 413-448页

作者： H.Lee B.Sengupta M.S.Araghizadeh R.S.myong School of Mechanical and Aerospace Engineering Gyeongsang National UniversityJinjuGyeongnam52828South Korea

Electric vertical take-off and landing(eVTOL)aircraft with multiple lifting rotors or prop-rotors have received significant attention in recent years due to their great potential for next-generation urban air mobility(UAM).Numerical models have been developed and validated as predictive tools to analyze rotor aerodynamics and wake *** various numerical approaches,the vortex method is one of the most suitable because it can provide accurate solutions with an affordable computational cost and can represent vorticity fields downstream without numerical dissipation *** paper presents a brief review of the progress of vortex methods,along with their principles,advantages,and *** of the vortex methods for modeling the rotor aerodynamics and wake dynamics are also ***,the vortex methods suffer from the problem that it cannot deal with the nonlinear aerodynamic characteristics associated with the viscous effects and the flow behaviors in the post-stall *** overcome the intrinsic drawbacks of the vortex methods,recent progress in a numerical method proposed by the authors is introduced,and model validation against experimental data is discussed in *** validation works show that nonlinear vortex lattice method(NVLM)coupled with vortex particle method(VPM)can predict the unsteady aerodynamic forces and complex evolution of the rotor wake.

关键词： Vortex methods Nonlinear vortex lattice method Viscous vortex particle method Rotor aerodynamics Wake dynamics

Ligand-free monophasic CuPd alloys endow boosted reaction kinetics toward energy-efficient hydrogen fuel production paired with hydrazine oxidation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第12期143卷 20-29页

作者： Yujeong Jeong Shreyanka Shankar Naik Yiseul Yu Jayaraman Theerthagiri Seung Jun Lee Pau Loke Show Hyun Chul Choi myong Yong Choi Department of Chemistry(BK21 FOUR) Research Institute of Natural SciencesGyeongsang National UniversityJinju 52828Republic of Korea Core-Facility Center for Photochemistry&Nanomaterials Gyeongsang National UniversityJinju 52828Republic of Korea Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection Wenzhou UniversityWenzhou 325035China Department of Chemical and Environmental Engineering Faculty of Science and EngineeringUniversity of Nottingham MalaysiaJalan Broga43500 SemenyihSelangor Darul EhsanMalaysia Department of Chemistry Chonnam National UniversityGwangju 61186Republic of Korea

Optimizing the structure and components is a prevalent strategy for increasing electrocatalytic energy-saving H 2 fuel *** of the sustainable and efficient techniques is electrocatalytic water split-ting for H 2 generation,but it is still restricted by the kinetically sluggish *** to the lower standard oxidation potential of−0.33 V,replacing the OER with anodic hydrazine oxidation reaction(HzOR)is an effective way to extensively reduce the use of electricity in water *** alloying,the semiconductor and adsorption characteristics of Cu,interlaced by Pd 2+solution on the Pd surface by pulsed laser ablation(PLA)in methanol,are selectively altered to maximize cathodic HER and anodic HzOR *** optimal Cu1Pd3/C ratio demonstrates outstanding HER performance with a low overpotential of 0.315 V at 10 mA cm^(−2),as well as an ultralow overpotential of 0.560 V for HzOR in 0.5 M N_(2) H_(4)/1.0 M ***,the constructed HzOR-assisted electrolyzer cell with Cu1Pd3/C||Cu1Pd3/C as anode and cathode exhibits a cell voltage of 0.505 V at 10 mA cm^(−2) with exceptional en-durance over 5 *** current study advances competent CuPd alloys as multifunctional electrocatalysts for H 2 fuel production using a HzOR-assisted energy-efficient electrolyzer.

关键词： PLA CuPd alloy Sonochemical process HzOR Hydrazine evolution reaction Hydrazine splitting Water splitting