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Numerical assessment on improving multistage centrifugal impeller performance by changing inlet skew angle at impeller inlet

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Journal of Central South University 2012年第4期19卷 953-961页

作者： M.N.Labib woo ju-sik Choi Du-youl T.Utomo B.Fajar Chung Han-shik Jeong Hyo-min Graduate School of Department of Mechanical and Precision Engineering Gyeongsang National UniversityTongyeong 650-160Korea Fluid and Thermal Engineering Co.Ltd. Kyungnam 621-843Korea Department of Mechanical Engineering Engineering FacultyUniversity of DiponegoroSemarang 1269Indonesia Department of Mechanical and Precision Engineering Gyeongsang National UniversityThe Institute of Marine Industr yTongyeong 650-160Korea Department of Mechanical and Precision Engineering Gyeongsang National UniversityThe Institute of Marine Industr yTongyeong 650-160Kore

Multistage centrifugal impellers with four different skew angles were investigated by using computational fluid *** purpose of this work is to investigate the influences of lean angle at the blade tip of the impeller *** variations of lean angles,that is,8°,10°,15° and 20°,were made at first stage *** Average Navier Stokes equation was used in simulation together with a shear?stress transport(SST) k-w turbulence model and mixing-plane approach,*** dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required.A good performance was expected that the secondary flow can be effectively reduced in the flow passage of the impeller without excessive increase in manufacturing cost caused by the secondary *** results show that secondary flow affects the main flow intricately to form vortices or having non-uniform velocity in the flow passage,which in turn results in substantial fluid energy loss not only in the impeller but also in the guide vane downstream of *** numerical solutions were performed and allowed the optimum design and operating conditions to be obtained.

关键词： computational fluid dynamics secondary flow blade inlet skew angle multistage centrifugal compressor

Estimation of genetic parameters on growth characteristics of a 35-year-old Pinus koraiensis progeny trial in South Korea

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Journal of Forestry Research 2021年第5期32卷 2227-2236页

作者： Kyungmi Lee In sik Kim Seok woo Lee Division of Forest Tree Improvement Department of Forest BioresourcesNational Institute of Forest ScienceSuwonRepublic of Korea

The effects of genetic and environmental factors on Pinus koraiensis growth were studied based on a35 year-old progeny trial composed of open-pollinated offspring of twenty-one plus ***,DBH and volume of the offspring was analyzed using restricted maximum likelihood/best linear unbiased prediction in mixed model *** site and family effects on the three traits were *** distinct growth of offspring by site with disparate climates corroborated the importance of planting species in suitable *** differences by family was significant,emphasizing the importance of identifying families with either superior or inferior *** parental ranking was assigned in the sites,inferring the breeding value of each plus *** estimates of individual heritability(h_(i)^(2))of height,DBH and volume growth were 0.169-0.645,0.108-0.331 and 0.129-0.343 respectively,with higher h_(i)^(2) of the height than DBH on each *** of variance of genetic effect was higher with DBH in some cases,indicating the scope for selection is larger for this trait despite the lower heritability compared to *** the variation between families in terms of the performance stability across sites,consideration of the genotype by environment interaction is required in selecting materials to be used in reforestation with Korean pine.A few families with either superior or inferior performance retained their parental ranking for at least a *** families with increased growth on a particular site were identified,indicating their high breeding value and low *** in the genetic performance of the families by site requires delineation of the breeding region of the species.

关键词： Pinus koraiensis Genetic parameters Genotype by environment interaction Tree improvement Progeny trial

Antioxidant and anti-inflammatory roles of tea polyphenols in inflammatory bowel diseases

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Food Science and Human Wellness 2022年第3期11卷 502-511页

作者： Van-Long Truong woo-sik Jeong Food and Bio-industry Research Institute School of Food Science&BiotechnologyCollege of Agriculture and Life SciencesKyungpook National UniversityDaegu 41566Korea

Polyphenols,including phenolic acids,flavonoids,and procyanidins,are abundant in food and beverage derived from ***(Camellia sinensis)is particularly rich in polyphenols(e.g.,catechins,theaflavins,thearubigins,gallic acid,and flavonols),which are thought to contribute to the health benefits of *** intake of tea polyphenols has been described to prevent and/or attenuate a variety of chronic pathological conditions like cardiovascular diseases,neurodegenerative diseases,diabetes,and *** review focuses on established antioxidant and anti-inflammatory properties of tea polyphenols and underlying mechanisms of their involvement in inflammatory bowel diseases(IBD).Tea polyphenols act as efficient antioxidants by inducing an endogenous antioxidant defense system and maintaining intracellular redox *** polyphenols also regulate signaling pathways such as nuclear factor-κB,activator protein 1,signal transducer and activator of transcriptions,and nuclear factor E2-related factor 2,which are associated with IBD *** pieces of evidence have indicated that tea polyphenols enhance epithelial barrier function and improve gut microbial dysbiosis,contributing to the management of inflammatory ***,this study suggests that supplementation of tea polyphenols could prevent inflammatory conditions and improve the outcome of patients with IBD.

关键词： Antioxidant Anti-inflammation Epithelial barrier function Inflammatory bowel diseases Gut microbiota Tea polyphenols

Visceral hypersensitivity and altered colonic motility after subsidence of inflammation in a rat model of colitis

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World Journal of Gastroenterology 2003年第12期9卷 2791-2795页

作者： jun-Ho La Tae-Wan Kim Tae-sik Sung Jeoung-woo Kang Hyun-ju Kim ⅠI-Suk Yang Department of Physiology College of Veterinary MedicineSeoul National UniversitySeoulRepublic of Korea

AIM:Irritable bowel syndrome(IBS)is a functional bowel disorder characterized by visceral hypersensitivity and altered bowel *** is increasing evidence suggesting the role of inflammation in the pathogenesis of IBS,which addresses the possibility that formerly established rat model of colitis could be used as an IBS model after the inflammation subsided. METHODS:Colitis was induced by intracolonic instillation of 4% acetic acid in male Sprague-Dawley *** extent of inflammation was assessed by histological examination and myeloperoxidase(MPO)activity *** subsidence of colitis,the rats were subjected to rectal distension and restraint stress,then the abdominal withdrawal reflex and the number of stress-induced fecal output were measured, respectively. RESULTS:At 2 days post-induction of colitis,the colon showed characteristic inflammatory changes in histology and 8-fold increase in MPO *** 7 days post-induction of colitis,the histological features and MPO activity returned to *** rats at 7 days post-induction of colitis showed hypersensitive response to rectal distension without an accompaning change in rectal compliance,and defecated more stools than control animals when under ***: These results concur largely with the characteristic features of IBS, visceral hypersensitivity and altered defecation pattern in the absence of detectable disease, suggesting that this animal model is a methodologically convenient and useful model for studying a subset of IBS.

关键词： Acetic Acid Animals Biological Markers Colitis Disease Models, Animal Inflammation Irritable Bowel Syndrome Male Pain Peroxidase Rats Rats, Sprague-Dawley Research Support, Non-U.S. Gov't

Solvent extraction and stripping of lithium ion from aqueous solution and its application to seawater

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Rare Metals 2016年第12期35卷 948-953页

作者： Gregorius Rionugroho Harvianto Seok-Hyeon Kim Chang-sik ju Department of Chemical Engineering Pukyong National University

For the development of lithium ion recovery process from seawater, a series of experimental researches were performed. Solvent extraction of lithium ion from aqueous solution using kerosene as solvent was proposed. Lithium ion is effectively extracted by thenoyltrifluoroace- tone-trioctylphosphine oxide （TTA-TOPO） in kerosene within 80 min. Extraction efficiency is severely influenced by stoichiometric parameters. Among the stoichiometric parameters, volume ratio of aqueous （A） to extraction （E） solution is the most influential parameter. After extrac- tion, lithium ion could be easily stripped from the extraction solution by acidic solutions. Stripping efficiency decreases with pH of acidic solutions, and the kind of acid does not affect the stripping efficiency. Extraction efficiency main- tains at more than 93 % even when the extraction solution is recycled three times. 65 % of lithium ion can be extracted from seawater by this solvent extraction process when magnesium ion is precipitated by NHaOH prior to solvent extraction process. Other metallic ions in seawater decrease the extraction efficiency of lithium ion.

关键词： Lithium Thenoyltrifluoroacetone Trioctylphosphine oxide Solvent extraction Stripping Recycling

Standardization of apple cancellation test for neglect patients in Korea:An observational study

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World Journal of Clinical Cases 2023年第22期11卷 5236-5243页

作者： woo-Hyuk Jang Jong-sik Jang Department of Occupational Therapy College of Health ScienceKangwon National UniversitySamcheok-si 25949Gangwon-doSouth Korea

BACKGROUND Neglect can be divided into two types using apple cancellation test(apple test):Egocentric neglect(EN)and allocentric neglect(AN).However,in South Korea,apple test results and decision criteria are still largely dependent on tests by foreign *** To establish a new South Korea standard and improve the accuracy of neglect assessment,the apple experiment was standardized in this *** This study was conducted on 223 healthy subjects for a total of 7 mo from August 2021 to February *** was carried out using the original apple test developed by Bickerton in *** scoring for the apple test,total omission error refers to the number of missed targets(full apple)in the entire test sheet(left,middle,and right area).The score for EN is the difference between the correct number of right area and the correct number of left area(excluding the middle area).For AN,the score is difference between the number of left opening apples and number of right opening apples(including the middle area).Linear regression analysis was used for standardization using the general characteristics of subjects and the results of the apple *** The cut-off score,which is the standard value indicating the pathological condition by combining the results of all subjects,is as follows:Total omission error(5),error for EN(2),and error for AN(2).Also,differences in cut-off score according to age were *** This study will be helpful in facilitating a more accurate differential diagnosis of neglect.

关键词： Apple cancellation test Egocentric neglect Allocentric neglect Brain injury Standardization

Naphthalene emissions from moth repellents or toilet deodorant blocks determined using head-space and small-chamber tests

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Journal of Environmental Sciences 2008年第8期20卷 1012-1017页

作者： JO Wan-Kuen LEE Jong-Hyo LIM Ho-Jin JEONG woo-sik Department of Environmental Engineering Kyungpook National UniversityDaegu 702-701Korea. School of Food and Life Science Inje University KimhaeKyungsangnarado 621-749Korea

The present study investigated the emissions of naphthalene and other compounds from several different moth repellents(MRs) and one toilet deodorant block(TDB)currently sold in Korea,using a headspace *** emission factors and emission rates of naphthalene were studied using a small-scale environmental ***-type products emitted a higher concentration of the total volatile organic compounds(VOCs)(normalized to the weight of test piece)than ball-type products,which in turn emitted higher con...

关键词： volatile organic compounds(VOCs) chemical composition ball-type gel-type paper-type

Effect of Al addition on corrosion behavior of high-purity Mg in terms of processing history

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Journal of Magnesium and Alloys 2023年第3期11卷 851-868页

作者： Sang Kyu woo Byeong-Chan Suh Ha sik Kim Chang Dong Yim Helmholtz Zentrum Hereon Max-Planck-Straße 1Geesthacht D-21502Germany Korea Institute of Materials Science 797 Changwondae-roSeongsan-guChangwonGyeongnam 51508Republic of Korea University of Science and Technology 217 Gajeong-roYuseong-guDaejeon 34113Republic of Korea

In this study,the effects of Al addition on the corrosion behavior of pure Mg with controlled impurity contents were systematically analyzed according to the processing *** results revealed that the corrosion behavior of high-purity Mg-Al alloys is strongly related to changes in the microstructure,including theβphase and Al-Mn or Al-Fe phases,and the protectiveness of the surface film according to the Al content and processing *** the as-cast alloys,the corrosion rate increased due to the increase ofβphase as the Al content increased,but in the as-extruded alloys,the corrosion rate,which was high due to intermetallic compounds caused by impurities in the low Al alloy,decreased as the Al content increased,and then increased *** is due to the combined effect of the increase of theβphase and decrease of the impurity effect,and the increase of the dissolved Al *** results suggest that it is necessary to analyze the effect of alloying elements on the corrosion behavior of pure Mg with information concerning the impurity content and processing history.

关键词： Mg High purity Mg-Al alloys Processing history Micro-galvanic Surface film

Synthesis and characterization of Ba(Co_xNb_(1-x))O_3 nanoparticles by hydrothermal processing

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中国有色金属学会会刊：英文版 2009年第B9期19卷 92-95页

作者： Hyun-ju KIM Min-Cheol CHU Seong-Jai CHO Dong-sik BAE School of Nano & Advanced Materials Engineering Changwon National University Materials Evaluation Center Korea Research Institute of Standards and Science

The nanosized Ba(CoxNb1-x)O3(BCN) particles were prepared under high temperature and pressure conditions by precipitation from metal nitrates with aqueous potassium hydroxide. Ba(CoxNb1-x)O3 powders were obtained in the temperature range of 170-210 ℃ for 6 h. The results show that the average size of the synthesized particles increases with increasing reaction temperature. The average size of the synthesized particles is about 10 nm. The crystalline phase of the synthesized particles is found to be Ba(CoxNb1-x)O3. Ceramics derived from the nano BCN powders could achieve high sintering density at a relatively low sintering temperature.

关键词：纳米粒子合成臭氧热加工表征平均粒径烧结温度氢氧化钾