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Experimental and Computational Studies on Coanda Nozzle Flow for the Air Knife Application

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Journal of Thermal Science 2007年第2期16卷 164-169页

作者： soon-bum kwon Dong-Won LEE Young-Doo kwon School of Mechanical Engineering Kyungpook National University1370Sankyuk-dongDaegu 702-701Korea

To control the film thickness of zinc in the process of continuous hot-dip galvanizing, it is known from the early days that the gas wiping through an air knife is the most effective one. The gas wiping using in galvanizing process brings about a problem of splashing from the strip edge for a certain high speed of coating. So, in the present study, the effects of the deflection angle of Coanda nozzle on jet structure and the distribution of impinging pres- sure at the plate surface are investigated numerically and experimentally. In numerical analysis, the governing equations consisted of three-dimensional time dependent full Navier-Stokes equations, standard k-ε turbulence model to solve turbulent stTess and so on are employed. In experiment, 16 channel pressure scanning valve and 3-axis auto traversing unit are used to measure the impinging pressure at the strip surface. As a result, it is found that the smaller the deflection angle for the same nozzle slit of air knife is, the larger the impinging pressure is. To reduce the size of separation bubble and to enhance the cutting ability, it is recommendable to use an air knife with the Coanda nozzle.

关键词： Air knife Coanda effect edge splashing gas wiping hot-dip galvanizing impinging jet

Stoichiometric Ti3C2Tx Coating for Inhibiting Dendrite Growth in Anode-Free Lithium Metal Batteries

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Energy & Environmental Materials 2024年第4期7卷 153-162页

作者： Xiangrong Zeng Manmatha Mahato Woong Oh Hyunjoon Yoo Van Hiep Nguyen Saewoong Oh Geetha Valurouthu soon-Ki Jeong Chi Won Ahn Yury Gogotsi Il-kwon Oh National Creative Research Initiative for Functionally Antagonistic Nano-Engineering Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) Department of Materials Science & Engineering and A. J. Drexel Nanomaterials Institute Drexel University Department of Energy Engineering Soonchunhyang University National Nanofab Center (NNFC) Korea Advanced Institute of Science and Technology (KAIST)

Lithium metal batteries (LMBs) and anode-free LMBs (AFLMBs) present a solution to the need for batteries with a significantly superior theoretical energy ***,their adoption is hindered by low Coulombic efficiency (CE) and rapid capacity fading,primarily due to the formation of unstable solid electrolyte interphase (SEI) layer and Li dendrite growth as a result of uneven Li plating.

关键词： anode-free lithium metal batteries stoichiometric MXene solid electrolyte interphase surface terminations

Long-term outcomes of very low birth weight infants with intraventricular hemorrhage:a nationwide population study from 2011 to 2019

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World Journal of Pediatrics 2024年第7期20卷 692-700页

作者： Joonsik Park Sook-Hyun Park Yu-ra kwon So Jin Yoon Joo Hee Lim Jung Ho Han Jeong Eun Shin Ho Seon Eun Min Soo Park soon Min Lee Department of Pediatrics Yonsei University College of Medicine211 Eonjuro GangnamguSeoul 06273Republic of Korea

Background Advancements in neonatal care have increased preterm infant survival but paradoxically raised intraventricular hemorrhage(IVH)*** study explores IVH prevalence and long-term outcomes of very low birth weight(VLBW)infants in Korea over a *** Using Korean National Health Insurance data(NHIS,2010-2019),we identified 3372 VLBW infants with IVH among 4,129,808 live ***-related claims data,encompassing diagnostic codes,diagnostic test costs,and administered procedures were sourced from the NHIS *** results of the developmental assessments are categorized into four groups based on standard deviation(SD)*** characteristics and complications were compared among the *** regression models were employed to identify significant changes in the incidence of complications and to calculate odds ratios with corresponding 95%confidence intervals for each risk factor associated with mortality and morbidity in ***-term growth and development were compared between the two groups(years 2010-2013 and 2014-2017).Results IVH prevalence was 12%in VLBW and 16%in extremely low birth weight(ELBW)*** the past decade,IVH rates increased significantly in ELBW infants(P=0.0113),while mortality decreased(P=0.0225).Major improvements in certain neurodevelopmental outcomes and reductions in early morbidities have been observed among VLBW infants with *** percent of the population received surgical treatments such as external ventricular drainage(EVD)or a ventriculoperitoneal(VP)shunt,with the choice of treatment methods remaining consistent over *** IVH with surgical intervention group exhibited higher incidences of delayed development,cerebral palsy,seizure disorder,and growth failure(height,weight,and head circumference)up to 72 months of age(P<0.0001).Surgical treatments were also significantly associated with abnormal developmental screening test *** The neurodevelopmental outcomes of infa

关键词： Cerebral intraventricular hemorrhage Developmental Hydrocephalus Mortality Posthemorrhagic ventricular dilatation Surgery

Acupuncture ameliorates atopic dermatitis by modulating gut barrier function in a gut microbiota-dependent manner in mice

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Journal of Integrative Medicine 2024年第5期22卷 600-613页

作者： Mijung Yeom Sora Ahn Dae-Hyun Hahm Sun-Young Jang Se Hoon Jang Su-Yang Park Jae-Hwan Jang Jihan Park Ju-Young Oh In-Seon Lee Kyuseok Kim soon-Kyeong kwon Hi-Joon Park Acupuncture and Meridian Science Research Center College of Korean MedicineKyung Hee University Department of Physiology School of MedicineKyung Hee University BioNanocomposite Research Center Kyung Hee University Department of Science in Korean Medicine College of Korean MedicineGraduate SchoolKyung Hee University College of Korean Medicine Kyung Hee University Department of Ophthalmology Otorhinolaryngology and Dermatology of Korean MedicineCollege of Korean MedicineKyung Hee University Division of Applied Life Science (BK21) Gyeongsang National University Department of Anatomy & Information Sciences College of Korean MedicineKyung Hee University

Objective: Atopic dermatitis(AD) is a chronic inflammatory skin disease that may be linked to changes in the gut microbiome. Acupuncture has been proven to be effective in reducing AD symptoms without serious adverse events, but its underlying mechanism is not completely understood. The purpose of this study was to investigate whether the potential effect of acupuncture on AD is gut ***: AD-like skin lesions were induced by applying MC903 topically to the cheek of the *** was done at the Gok-Ji(LI11) acupoints. AD-like symptoms were assessed by lesion scores,scratching behavior, and histopathological changes; intestinal barrier function was measured by fecal output, serum lipopolysaccharide levels, histopathological changes, and mRNA expression of markers involved in intestinal permeability and inflammation. Gut microbiota was profiled using 16S rRNA gene sequencing from fecal ***: Acupuncture effectively improved chronic itch as well as the AD-like skin lesions with epidermal thickening, and also significantly altered gut microbiota structure as revealed by β-diversity indices and analysis of similarities. These beneficial effects were eliminated by antibiotic depletion of gut microbiota,but were reproduced in gut microbiota-depleted mice that received a fecal microbiota transplant from acupuncture-treated mice. Interestingly, AD mice had intestinal barrier dysfunction as indicated by increased intestinal permeability, atrophy of the mucosal structure(reduced villus height and crypt depth), decreased expression of tight junctions and mucus synthesis genes, and increased expression of inflammatory mediators in the ileum. Acupuncture attenuated these abnormalities, which was gut ***: Acupuncture ameliorates AD-like phenotypes in a gut microbiota-dependent manner and some of these positive benefits are explained by modulation of the intestinal barrier, providing new perspective for non-phar

关键词： Acupuncture Atopic dermatitis Gut microbiota Intestinal barrier function

Influence of Indian mustard (Brassica juncea) on rhizosphere soil solution chemistry in long-term contaminated soils:A rhizobox study

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Journal of Environmental Sciences 2010年第1期22卷 98-105页

作者： kwon-Rae Kim Gary Owens soon-lK kwon Climate Change & Agroecology Division Department of Agricultural EnvironmentNational Academy of Agricultural ScienceRDARepublic of Korea Centre for Environmental Risk Assessment and Remediation University of South Australia

This study investigated the influence of Indian mustard （Brassicajuncea） root exudation on soil solution properties （pH, dissolved organic carbon （DOC）, metal solubility） in the rhizosphere using a rhizobox. Measurement was conducted following the cultivation of Indian mustard in the rhizobox filled four different types of heavy metal contaminated soils （two alkaline soils and two acidic soils）. The growth of Indian mustard resulted in a significant increase （by 0.6 pH units） in rhizosphere soil solution pH of acidic soils and only a slight increase （〈 0.1 pH units） in alkaline soils. Furthermore, the DOC concentration increased by 17-156 mg/L in the rhizosphere regardless of soil type and the extent of contamination, demonstrating the exudation of DOC from root. Ion chromatographic determination showed a marked increase in the total dissolved organic acids （OAs） in rhizosphere. While root exudates were observed in all soils, the amount of DOC and OAs in soil solution varied considerably amongst different soils, resulting in significant changes to soil solution metals in the rhizosphere. For example, the soil solution Cd, Cu, Pb, and Zn concentrations increased in the rhizosphere of alkaline soils compared to bulk soil following plant cultivation. In contrast, the soluble concentrations of Cd, Pb, and Zn in acidic soils decreased in rhizosphere soil when compared to bulk soils. Besides the influence of pH and DOC on metal solubility, the increase of heavy metal concentration having high stability constant such as Cu and Pb resulted in a release of Cd and Zn from solid phase to liquid phase.

关键词： dissolved organic carbon heavy metals root exudates solubility rhizosphere chemistry

Study of material removal behavior on R-plane of sapphire during ultra-precision machining based on modified slip-fracture model

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Nanotechnology and Precision Engineering 2020年第3期3卷 141-155页

作者： Suk bum kwon Aditya Nagaraj Hae-Sung Yoon Sangkee Min Department of Mechanical Engineering University of Wisconsin-Madison1513 University AvenueMadisonWI 53706United States of America School of Aerospace and Mechanical Engineering Korea Aerospace University76 Hanggongdaehak-roDeogyang-guGoyang-siGyeonggi-do 10540Republic of Korea

In this paper, the modified slip/fracture activation model has been used in order to understand the mechanism of ductile-brittle transition on the R-plane of sapphire during ultra-precision machining by reflecting direction of resultant force. Anisotropic characteristics of crack morphology and ductility of machining depending on cutting direction were explained in detail with modified fracture cleavage and plastic deformation parameters. Through the analysis, it was concluded that crack morphologies were mainly determined by the interaction of multiple fracture systems activated while, critical depth of cut was determined by the dominant plastic deformation parameter. In addition to this, by using proportionality relationship between magnitude of resultant force and depth of cut in the ductile region, an empirical model for critical depth of cut was developed.

关键词： Ductile-brittle transition Crack morphology Single crystal sapphire Deformation mechanism Orthogonal cutting Ultra-precision machining

Evaluation of particle growth systems for sampling and analysis of atmospheric fine particles

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Particuology 2011年第6期9卷 606-610页

作者： Dae Seong Kim Sang bum Hong Jung-Taek kwon Kihong Park Department of Environmental Science and Engineering Gwangju Institute of Science and Technology Korea Polar Research Institute Laboratory of Toxicology College of Veterinary Medicine Seoul National University

Three types of water-based condensational growth systems, which can enable particles to grow in size to facilitate sampling and subsequent chemical analysis, were evaluated. The first one is a mixing type growth system where aerosols are mixed with saturated water vapor, the second one is a thermal diffusive growth system where warm flow enters cold-walled tube, and the third one is a laminar flow type where cold flow enters a warm wet-wall tube. Hygroscopic sodium chloride （NaCl）, ammonium sulfate （（NH4）2SO4） and ammonium nitrate （NH4N03）, and non-hygroscopic polystyrene latex （PSL） particles, in the size range of 50-400 nm, were used to determine their growth factors through the growth systems. Our data showed that the third-type growth system could enable particles to grow most efficiently regardless of their hygroscopic property. Collection efficiency of particles in the size range of 0.05-2.5 μm, in a continuous aerosol sampler after they passed through the third-type growth system was about 100%, suggesting that the third-type growth system would he the most useful among the tested growth systems for sampling and subsequent chemical analysis of fine and ultrafine particles.

关键词： Particle growth chamber Condensational growth Particle sampler Hygroscopic particles

Optimal rotor wear design in hypotrochoidal gear pump using genetic algorithm

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Journal of Central South University 2011年第3期18卷 718-725页

作者： kwon soon-man KIM Chang-Hyun SHIN Joong-ho Department of Mechanical Design and Manufacturing Engineering Changwon National University

The wear rate between the rotors of a hypotrochoidal gear pump is *** the knowledge of shape design on the rotors,the contact stresses without hydrodynamic effect between the rotor teeth were evaluated through the calculation of the Hertzian contact *** on the above results and the sliding velocity between the rotors,a genetic algorithm (GA) was used as an optimization technique forminimizing the wear rate proportional factor (WRPF).The result shows that the wear rate or the WRPF can be reduced considerably,*** 12.8%,throughout the optimization using GA.

关键词： gerotor hypotrochoidal gear pump Hertzian contact stress wear rate proportional factor genetic algorithm

Kinematical system of breadth cam profile design

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Journal of Central South University 2011年第2期18卷 451-457页

作者： SHIN Joong-ho 李琳 YANG Hyun-dai kwon soon-man Department of Mechanical Design & Manufacturing Changwon National University

The design solutions for breadth cam mechanism was presented. The main topics of the shape design for breadth cam was to calculate the coordinate at each contact point to determine the cam profile. The proposed method according to velocity and geometric relationships of instant velocity centers can easily determine each contact point at any instant moment. The cam profile was defined by contouring of the contact points. And also a program was developed by using Microsoft Visual C++ program,which can quickly and easily draw a 2D cam profile through the displacement diagram. Finally,the program was used to confirm the accuracy on the breadth cam profile design by computer animation graphically.

关键词： cam profile breadth cam reciprocating follower oscillating follower instant velocity center