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Computational Analysis of a Variable Ejector Flow

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Journal of Thermal Science 2006年第2期15卷 140-144页

作者： h.D. kim J.h. LEE T. SETOgUChI S.MATSUO School of Mechanical Engineering Andong National University 388 Songchun-dong Andong 760-749 Korea Department of Mechanical Engineering Saga University 1 Honjo Saga 840-8502 Japan

The present study addresses a variable ejector which can improve the ejector efficiency and control the re-circulation ratio under a fixed operating pressure ratio. The variable ejector is a facility to obtain specific recirculation ratio under a given operating pressure ratio by varying the ejector throat area ratio. The numerical simulations are carried out to provide an understanding of the flow characteristics inside the variable ejector. The sonic and supersonic nozzles are adopted as primary driving nozzles in the ejector system, and a movable cone cylinder, inserted into a conventional ejector-diffuser system, is used to change the ejector throat area ratio. The numerical simulations are based on a fully implicit finite volume scheme of the compressible, Reynolds-Averaged Navier-Stokes equations. The results show that the variable ejector can control the recirculation ratio at a fixed operating pressure ratio.

关键词： variable ejector ejector throat area ratio re-circulation ratio

Microstructure and properties of hot extruded AZ31-0.25%Sb Mg-alloy

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中国有色金属学会会刊：英文版 2008年第A1期18卷 17-21页

作者：田素贵王岭 K.Y.ShON K.h.kim School of Materials Sciences and Engineering Shenyang University of Technology Materials Engineering Department Korea Institute of Machinery and Materials

The effects of hot extrusion treatment on the microstructure and mechanical properties of AZ31-0.25%Sb Mg alloy were investigated by means of mechanical properties measurement and microstructure *** results show that the microstructure of AZ31-0.25%Sb Mg alloys consists ofα-Ms matrix,Mg_(17)Al_(12) and Mg_3Sb_2 *** ultimate tensile strength (UTS) and yield tensile strength(YTS) of the alloy are obviously enhanced by hot extrusion treatment,and the enhanced extent of UTS and YTS increases with the decrease of hot extrusion temperature,moreover,the YTS value of the alloy at RT,after extruded at 220℃,increases up to 131.4%,which attributes to the finer grains resulted from the dynamic recrystallization occurred during hot *** hot extrusion goes on,the slipping and concentration of dislocations continue to occur within the finer grains,which promotes the formation of the subgrains in the *** deformation features of the extruded alloy during tensile deformation at RT are the twinning deformation and dislocation slipping in the twinning ***,the deformation mechanisms of the alloy are a dislocation activation on the basal plane and a+c dislocation activation on the pyramidal planes.

关键词：镁合金高温挤压处理微观结构

Successful treatment of a high-risk nonseminomatous germ cell tumor using etoposide, methotrexate, actinomycin D, cyclophosphamide, and vincristine: A case report

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World Journal of Clinical Cases 2020年第21期8卷 5334-5340页

作者： Jina Yun Sang W Lee Sung h Lim Se h kim Chan K kim Seong K Park Department of Internal Medicine Division of Hematology-OncologySoonchunhyang University Bucheon HospitalSoonchunhyang University School of MedicineBucheon 14584South Korea Department of Urology and Internal Medicine Soonchunhyang University Bucheon HospitalSoonchunhyang University School of MedicineBucheon 14584South Korea

BACKgROUND Choriocarcinoma is an infrequent entity and the most aggressive subtype of germcell *** of early metastatic spread and rapid disease progression,choriocarcinoma patients display poor *** etoposide,methotrexate,actinomycin D,cyclophosphamide,and vincristine(EMA-CO)regimen is widely used to treat gestational trophoblastic tumors in females,its role in treating male choriocarcinoma is seldom *** SUMMARY A 32-year-old man was diagnosed with burned-out primary germ cell tumors(gCT)with retroperitoneum,liver and lung *** of the liver revealed pure *** patient received bleomycin,etoposide,and cisplatin *** two cycles of treatment,response evaluation revealed the mixed ***-CO regimen was used in the second-line *** eight cycles,the patient showed a potentially resectable state and thus,all residual masses were surgically *** patient was completely cured,and 10 years later,he is leading a healthy life without *** This paper is the first case of high-risk nonseminomatous gCT in a male patient to be successfully treated with the EMA-CO *** EMA-CO regimen can be used actively in patients with high-risk nonseminomatous gCT.

关键词： Antineoplastic combined chemotherapy protocols Choriocarcinoma Testicular neoplasms Cyclophosphamide Methotrexate Case report

Plasma density measurement and downstream etching of silicon and silicon oxide in Ar/NF3 mixture remote plasma source

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Plasma Science and Technology 2019年第6期21卷 52-57页

作者： h J YEOM D h ChOI Y S LEE J h kim D J SEONg S J YOU h C LEE Korea Research Institute of Standards and Science(KRISS) Daejeon 34113 Republic of Korea Department of Physics Chungnam National University Daejeon 34134 Republic of Korea

In this study,plasma density measurements were performed near the plume region of the remote plasma source (RPS) in Ar/NF3 gas mixtures using a microwave cutoff *** measured plasma density is in the range of 1010-1011 cm-3 in the discharge conditions with RPS powers of 2-4 kW and gas pressures of 0.87-4 *** plasma density decreased with increasing gas pressures and RPS powers under various Ar/NF3 mixing *** decrease in the plasma density measured at the fixed measurement position (plume region) can be understood by the reduction of the electron energy relaxation length with increases in the gas pressures and mixing ratio of NF3/(Ar/NF3).We also performed downstream etching of silicon and silicon oxide films in this *** etch rate of the silicon films significantly increases while the silicon oxide is slightly etched with the gas pressures and *** was also found that the etch rate strongly depends on the wafer position on the processing chamber electrode,and that the etch selectivity reached 96-131 in the discharge conditions of RF powers (3730-4180 W) and gas pressures (3.6-4 Torr).

关键词： remote plasma source electron density cutoff probe downstream etch

Study of Thermal and hydraulic Performances of Circular and Square Ribbed Rough Microchannels Using LBM

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Journal of Thermal Science 2015年第6期24卷 549-556页

作者： M.A.Taher h.D.kim Y.W Lee Department of Mechanical and Automotive Engineering Pukyong National University Department of Mechanical Engineering Andong National University

The effects of roughness geometries and relative roughness height at the slip flow regime to investigate the thermal and hydraulic performances of microchannel have been considered in the present article using a thermal Lattice Boltzmann Method(TLBM).A two dimensional 9-bit(D2Q9)single relaxation time(SRT)model is used to simulate this *** micro-flows,the local density variation is still relatively small,but the total density changes,therefore,in order to account this density variation and its effect on the kinematic viscosityν,a new relaxation time proposed by Niu et al.[13]is *** roughness geometry is modeled as a series of square and circular riblets with a relative roughness height from 0%to 10%of the channel *** friction coefficients in terms of Poiseuille number(Pn)and the dimensionless heat transfer rate in terms of Nusselt number(Nu)have been discussed in order to analyze the roughness *** thermal-hydraulic performance(η)is calculated considering the simultaneous effects of thermal and fluid friction(pressure drop)at the slip flow regime at Knudsen number,Kn,ranging from 0.01 to 0.10 with other controlling parameters for both kind of *** results have been compared with previous published works and it is found to be in very good agreement.

关键词： Lattice-Boltzmann Friction factor Knudsen number Surface Roughness

Microstructure and creep properties of Mg-4Al-2Sn-1(Ca,Sr) alloys

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Transactions of Nonferrous Metals Society of China 2010年第7期20卷 1184-1191页

作者： B.h.kim K.C.PARK Y.h.PARK I.M.PARK Department of Material Science and Engineering Pusan National UniversitySan 30 Jangjeon-dongGeumjeong-guBusan 609-735Korea

The effects of Ca and Sr addition on the microstructure and creep properties of Mg-4Al-2Sn alloys were examined. Tensile tests at 25 ℃ and 200 ℃ and creep tests at 150 ℃ and 200 ℃ were carried out to estimate the room temperature and high temperature mechanical properties of these alloys. The microstrueture of the Mg-4Al-2Sn alloy showed dendritic a-Mg, Mg17Al12 and Mg2Sn phases. The latter two phases precipitated along the grain boundaries. The addition of Ca and Sr resulted in the formation of ternary CaMgSn and SrMgSn phases within the grain. The grain size was reduced slightly with the addition of Sr and Ca. The tensile strength was decreased by the addition of Ca and Sr at room temperature. however, the high temperature tensile strength was increased. The creep strength was improved by the addition of Ca and Sr.

关键词： magnesium alloys Ca Sr void initiation mechanical properties creep mechanism

Nanotube-Based Chemical and Biomolecular Sensors

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Journal of Materials Science & Technology 2008年第4期24卷 578-588页

作者： J.Koh B.kim S.hong h.Lim h.C.Choi Department of Physics and Astronomy Seoul National University Shillim-Dong Kwanak-Gu Seoul 151-747 Korea Department of Chemistry Pohang University of Science and Technology San 31 Hyoja-Dong Nam-Gu Pohang 790-784 Korea

We present a brief review about recent results regarding carbon nanotube （CNT）-based chemical and biomolecular sensors. For the fabrication of CNT-based sensors, devices containing CNT channels between two metal electrodes are first fabricated usually via chemical vapor deposition （CVD） process or ＂surface programmed assembly＂ method. Then, the CNT surfaces are often functionalized to enhance the selectivity of the sensors. Using this process, highly-sensitive CNT-based sensors can be fabricated for the selective detection of various chemical and biological molecules such as hydrogen, ammonia, carbon monoxide, chlorine gas, DNA, glucose, alcohol, and proteins.

关键词： Chemical vapour deposition Carbon nanotubes Sensors Biological molecules Surface programmed assembly

Enzymatic oxidation of aqueous pentachlorophenol

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Journal of Environmental Sciences 2007年第9期19卷 1032-1036页

作者： E. Y. kim h. J. Chae K. h. Chu Department of Chemical Engineering The University of Seoul Seoul 130-743 Korea. Departments of Food and Biotechnology and Innovative Industrial Technology Hoseo University Asan 336-795 Korea honeywell Process Solutions 17 Changi Business Park Central 1 Singapore 486073

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.

关键词： biocatalysis horseradish peroxidase pentachlorophenol surfactant

Evaluation of spermatogenesis and fertility in F1 male rats after in utero and neonatal exposure to extremely low frequency electromagnetic fields

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Asian Journal of Andrology 2005年第2期7卷 189-194,页

作者： M.K.Chung S.J.Lee Y.B.kim S.C.Park D.h.Shin S.h.kim J.C.kim Reproductive Toxicology Division Korea Institute of ToxicologyKorea Research Institute of Chemical TechnologyDaejeon 305-600Korea College of Veterinary Medicine Chungbuk National UniversityCheongju 361-763Korea College of Veterinary Medicine Kyungpook National UniversityDaegu 702-701Korea College of Veterinary Medicine Chonnam National UniversityGwangju 500-757Korea

Aim:To determine whether in utero and neonatal exposure to a 60 hz extremely low frequency electromagnetic field (EMF) results in spermatotoxicity and reproductive dysfunction in the F1 offspring of ***:Age-matched, pregnant Sprague-Dawley rats were exposed continuously (21 h/day) to a 60 hz EMF at field strengths of 0 (sham control),5,83.3 or 500 μT from day 6 of gestation through to day 21 of *** experimentally generated magnetic field was monitored continuously (uninterrupted monitoring over the period of the study) throughout the ***:No exposure-related changes were found in exposed or sham-exposed animals with respect to the anogenital distance,preputial separation,testis weight,testicular histology,sperm count,daily sperm production, sperm motility,sperm morphology and reproductive capacity of F1 ***:Exposure of Sprague- Dawley rats to a 60 hz EMF at field strengths of up to 500 μT from day 6 of gestation to day 21 of lactation did not produce any detectable alterations in offspring spermatogenesis and fertility.

关键词： spermatogenesis electromagnetic fields prenatal exposure postnatal exposure rat