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Velocity Profiles between Two Baffles in a Shell and Tube Heat Exchanger

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Journal of Thermal Science 2015年第4期24卷 356-363页

作者： Tae-Hyun Chang Chang-Hoan lee Hae-Soo lee kwon-Soo lee Senior Research Fellow of RESEAT Korea Institute of Science and Technology Information Korea Institute of Science and Technology Information Postdoctoral Research Fellow School of Mechanical Engineering of Kyungnam University International University of Korea

Heat exchangers are extensively utilized for waste heat recovery,oil refining,chemical processing,and steam *** this study,velocity profiles are measured using a 3D particle image velocimetry(PIV)system between two baffles in a shell and tube heat exchanger for parallel and counter *** PIV and computational fluid dynamics results show the occurrence of some strong vectors near the *** vectors are assumed due to the clearance between the inner tubes and the front ***,the major parts of the vectors are moved out through the bottom opening of the rear baffle,and other vectors produce a large circle between the two *** simulations are conducted to investigate the effects of the baffle on the heat exchanger using the Fluent *** k-εturbulence model is employed to calculate the flows along the heat exchanger.

关键词： Baffle P1V Shell and tube heat exchanger Cut off ratio CFD

On the Classification of Positive Quaternionic Khler Manifolds with b_4=1

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Acta Mathematica Sinica,English Series 2010年第5期26卷 875-884页

作者： Jin Hong KIM Hee kwon lee Department of Mathematical Sciences Korea Advanced Institute of Science and Technology Guseong-dong

Let M be a positive quaternionic Kahler manifold of dimension 4m. We already showed that if the symmetry rank is greater than or equal to [m/2] ＋ 2 and the fourth Betti number b4 is equal to one, then M is isometric to HPm. The goal of this paper is to report that we can improve the lower bound of the symmetry rank by one for higher even-dimensional positive quaternionic Kahler manifolds. Namely, it is shown in this paper that if the symmetry rank of M with b4（M） = 1 is greater than or equal to m/2 ＋ 1 for m ≥ 10, then M is isometric to HPm. One of the main strategies of this paper is to apply a more delicate argument of Frankel type to positive quaternionic Kahler manifolds with certain symmetry rank.

关键词： positive quaternionic Kahler symmetry

High resolution aerosol optical thickness retrieval over the Pearl River Delta region with improved aerosol modelling

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Science China Earth Sciences 2009年第10期52卷 1641-1649页

作者： WONG ManSing NICHOL Janet lee kwon Ho Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic University Earth System Science Interdisciplinary Center University of Maryland (UMD)

Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, a new aerosol retrieval algorithm using the MODIS 500 m resolution images is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta region. The rationale of our technique is to first estimate the aerosol reflectance by decomposing the top-of-atmosphere reflectance from surface reflectance and Rayleigh path reflectance. For the determination of surface reflectance, a modified Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. A strong correlation is shown between the surface reflectance of MRT images and MODIS land surface reflectance products (MOD09), with a value of 0.9. For conversion of aerosol reflectance to Aerosol Optical Thickness (AOT), comprehensive Look Up Tables (LUT) are constructed, in which aerosol properties and sun-viewing geometry in the radiative transfer calculations are taken into account. Four aerosol types, namely mixed urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on three years of AERONET measurements in Hong Kong. Their aerosol properties were input for LUT calculation. The resulting 500 m AOT images are highly correlated (r = 0.89) with AERONET sunphotometer observations in Hong Kong. This study demonstrates the applicability of aerosol retrieval at fine resolution scale in urban areas, which can assist the study of aerosol loading distribution and the impact of localized and transient pollution on urban air quality. In addition, the MODIS 500 m AOT images can be used to study cross-boundary aeroso

关键词： aerosol retrieval aerosol optical thickness AERONET MODIS satellite image

Cell architecture designs towards high-energy-density microscale energy storage devices

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Nano Research Energy 2024年第2期3卷 69-82页

作者： kwon-Hyung lee Sang-Young lee Ulsan Advanced Energy Technology R&D Center Korea Institute of Energy Research(KIER)Ulsan44776Republic of Korea Department of Chemical and Biomolecular Engineering Yonsei UniversitySeoul03722Republic of Korea

The rapid growth of miniaturized electronics has led to an urgent demand for microscale energy storage devices(MESDs)to sustainably power the micro electronic ***,most MESDs reported to date have suffered from the limited energy densities and shape versatility compared to conventional large-scale counterparts because of the architectural constraints inherent in microfabrication-based cell manufacturing and cell dimension/*** review addresses the cell architecture design for MESDs that can achieve both miniaturization and high energy *** provide a comprehensive overview of five types of cell architectures of MESDs and their fabrication *** addition,to enable practical applications of MESDs,several cell design approaches are presented with the aim of minimizing the inactive parts of the cell and maximizing the performance metrics of ***,we discuss development direction and outlook of MESDs with a focus on materials chemistry,energy-dense electrochemical systems,and cell performance normalization,which will help to expand their applications and manufacturing scalability.

关键词： microscale energy storage device cell architecture microfabrication miniaturization high-energy-density

Synergetic analysis of springtime air pollution episodes over Gwangju,Korea

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Journal of Environmental Sciences 2017年第7期29卷 270-283页

作者： Sung-Kyun Shin kwon-Ho lee Seung-Shik Park Man Sing Wong Research Institute for Radiation-Satellite(RIRS) Gangneung-Wonju National University(GWNU)Gangneung 25457Republic of Korea Department of Atmospheric and Environmental Sciences(DAES) Gangneung-Wonju National University(GWNU)Gangneung 25457Republic of Korea Department of Environment and Energy Engineering Chonnam National UniversityGwangju 61186Republic of Korea Department of Land Surveying and Geo-Informatics The Hong Kong Polytech UniversityKowloonHong Kong

The characteristics of springtime aerosols,including their optical and microphysical properties,were analyzed for the months of March to May of 2009 in Gwangju（35.23°N,126.84°E）,Korea.A high Light Detection and Ranging（LIDAR）-derived aerosol depolarization ratio（δ） of 0.25 ± 0.04 was determined on dust particles during the observation ***？ngstr？m exponent values of the 440–870 nm wavelength pair（？_（440–870）） and single-scattering albedo at 675 nm（Ω_（675）） measured by a CIMEL sun/sky radiometer were 0.77 ± 0.19 and 0.95 ±0.01,*** elevated dust layers reached a maximum elevation of 4 km above sea ***/smoke particles that originated from highly populated/industrialized regions could be distinguished by their relatively smaller particle size（？_（440–870） ranged between1.33 and 1.36） and higher light-absorbing（Ω_（675） of 0.92 ± 0.01） *** aerosols are mostly distributed at altitudes 〈 1.2 *** root-mean-square deviation（RMSD） between the aerosol optical depth（AOD,τ） derived from LIDAR_（（τ_（LIDAR））） and from the CIMEL sun/sky radiometer_（（τ_（CIMEL））） varied with respect to the surface PM10 *** RMSD between τ_（LIDAR） and τ_（CIMEL） was as low as 13% under lower PM_（10） concentration levels（〈 100 μg/m^3）.In contrast,the RMSD between τ_（LIDAR） and τ_（CIMEL） increased three times（~31%） under high surface PM_（10） concentration levels（〉100 μg/m^3）.These results suggest that the accuracy of τ_（LIDAR） is influenced by specific atmospheric conditions,regardless of its uncertainty.

关键词： LIDAR Sun/sky radiometer MODIS Optical/microphysical properties Aerosol optical depth

Effect of Annular Slit Geometry on Characteristics of Spiral Jet

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Journal of Thermal Science 2003年第3期12卷 225-230页

作者： Shigeru Matsuo kwon-Hee lee Shinsuke Oda Toshiaki Setoguchi Heuy-Dong Kim Department of Mechanical Engineering Saga University 1 Honjo-machi Saga-shi Saga 840-8502Japan School of Mechanical Engineering College of Natural Science Andong National University388 Song-Cheon Dong Andong Kyung-Pook Korea

A spiral flow using an annular slit connected to a conical cylinder does not need special device to generate a tangential velocity component of the flow and differs from swirling flows. Pressurized fluid is supplied to an annular chamber and injected into the convergent nozzle through the annular slit. The annular jet develops into the spiral flow. In the present study, a spiral jet discharged out of nozzle exit was obtained by using a convergent nozzle and an annular slit set in nozzle inlet, and the effect of annular slit geometry on characteristics of the spiral jet was investigated by using a Laser Doppler Velocimeter (LDV) experimentally. Furthermore, velocity distributions of the spiral jet were compared with those of a normal jet.

关键词： spiral jet flow convergent nozzle annular slit LDV

Antioxidant activity and free radical scavenging activities of Streptomyces *** MJM 10778

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Asian Pacific Journal of Tropical Medicine 2014年第12期7卷 962-967页

作者： Dong-Ryung lee Sung-kwon lee Bong-Keun Choi Jinhua Cheng Young-Sil lee Seung Hwan Yang Joo-Won Suh Division of Bioscience and Bioinformatics Myongji UniversityYoungin-siGyeonggi-do 449728Korea Center for Neutraceutical and Pharmaceutical Materials Myongji UniversityYongin-siGyeonggi-do 449728Korea

Objective:To investigate the antioxidant activity of soil-borne ***:The total phenolic contents,the level of antioxidant potential by DPPH radical scavenging activity,MO scavenging activity,and ABTS radical scavenging activity in ethyl acelale extract were ***:The 16 S rDNA sequencing analysis revealed that Streptomyces *** MJM *** was isolated from Hambak ***,has 99.9% similarity to Streptomyces misionensis(***) NBRC *** physiological and the morphological test revealed that the strain MJM 10778 has different characteristics from the strain *** entire antioxidant assay with the ethyl acelale extract displayed good radical scavenging *** IC_(50) values of the strain MJM 10778 extract on DPPH,.*** ABTS radicals were identified to he 92.8 μg/mL,0.02 μg/ml,and 134.9 μg/mL,*** ethyl acetate extract of the strain MJM 10778 showed an 81.500% of cell viability at 100 μg/mL in Raw264.7cell viability ***:The results obtained suggesl that the ethyl acetate extract of Streptomyces *** MJM 10778 could be considered as a potential source of drug for the diseases that is caused by free radicals with its anti-oxidant activities and low cytotoxicity.

关键词： Streptomyces sp.strain MJM 10778 Antioxidant activity DPPH radical scavenging assay NO radical scavenging assay

Molecular approaches for the detection and monitoring of microbial communities in bioaerosols:A review

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Journal of Environmental Sciences 2017年第1期29卷 234-247页

作者： Keunje Yoo Tae kwon lee Eun Joo Choi Jihoon Yang Sudheer Kumar Shukla Sang-il Hwang Joonhong Park Department of Civil and Environmental Engineering Yonsei UniversitySeoul 03722South Korea Department of Environmental Engineering Yonsei UniversityWonju 26493South Korea Department of Systems Biology Yonsei UniversitySeoul 03722South Korea Department of Built and Natural Environment Caledonian College of EngineeringSultanate of Oman Division of Natural Resources Conservation Korea Environment InstituteSejong-si 30147South Korea

Bioaerosols significantly affect atmospheric processes while they undergo long-range vertical and horizontal transport and influence atmospheric chemistry and physics and climate *** evidence suggests that exposure to bioaerosols may cause adverse health effects,including severe *** of bioaerosols have primarily focused on their chemical composition and largely neglected their biological composition and the negative effects of biological composition on ecosystems and human ***,current molecular methods for the identification,quantification,and distribution of bioaerosol agents are *** developments in environmental microbiology technology would be favorable in elucidation of microbial temporal and spatial distribution in the atmosphere at high *** addition,these provide additional supports for growing evidence that microbial diversity or composition in the bioaerosol is an indispensable environmental aspect linking with public health.

关键词： Bioaerosol Airborne microbial community Molecular methods Metagenomics

Bee wax coated water-soluble fraction of bee venom improved altered glucose homeostasis in streptozotocin-induced diabetic rats

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Journal of Traditional Chinese Medicine 2019年第6期39卷 842-852页

作者： Rangachari Balamurugan Jeong Hwa Kim Mi-na Jo Chenglian Xue Jin kyu Park Jae kwon lee Department of Beesen Lab 204Beesen Co.Ltd.Bioventure TownYuseong Daero 1662Dae Jeon 34054Republic of Korea Department of Biology Education College of EducationChungbuk National UniversityCheongju 28644Republic of Korea

OBJECTIVE:To evaluate the anti-diabetic efficacy of orally administered bee wax coated water-soluble fraction of bee venom(BWCBVA)drug over orally administered bee wax(BW)and intraperitoneally administered whole bee venom(BV)in streptozotocin(STZ)-induced diabetic ***:Diabetes induced by intraperitoneal administration of 60 mg/kg STZ was treated with BWCBVA,BW,and BV for 21 *** biochemical,protein and histological changes,and physical characteristics of BWCBVA were then ***:The BWCBVA group shows significantly decreased blood glucose level as compared to the BW and intraperitoneally administered whole BV treated ***,BWCBVA significantly normalizes the serum biochemical parameters and increases the body ***,administration of BWCBVA significantly reverses the altered liver expression of phosphatidylinositide 3-kinases-p85 and liver *** analysis of the pancreas an increase in the islet cell numbers and decrease inβ-cell ***-administering BWCBVA 0.25 mg/kg with nifedipine(6.8 mg/kg)and nicorandil(13.8 mg/kg)to the diabetic rats results in insulin secretion through enhanced calcium ion *** performance liquid chromatography and gas chromatography was performed to identify the pharmacologically important compounds present in ***:Our results indicate that BWCBVA,an orally administered colon specific drug delivery system,can be effective in treating diabetes mellitus.

关键词： Diabetes Mellitus Waxes Bee venoms Streptozotocin