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Heat transfer characteristics of nanofluid through circular tube

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Journal of Central South University 2013年第1期20卷 142-148页

作者： WUSIMAN Ku-er-ban-jiang CHUNG Han-shik MD.J.Nine HANDRY Afrianto EOM Yoon-sub KIM Jun-hyo jeong hyo-min Department of Mechanical and Precision Engineering GyeongSang National University445 Inpyeong-dongTongYoungGyeongNam 650-160Korea Department of Energy and Mechanical Engineering The Institute of Marine IndustryGyeongSang National University445 Inpyeong-dongTongYoungGyeongNam 650-160Korea Division of Marine Engineering Mokpo National Maritime UniversityHaeyangdaehang-Ro 91Mokpo-siJeollanam-do530-729Korea

Nano fluid is considered to be a class of high efficient heat transfer fluid created by dispersing some special solid nanoparticles (normally less than 100 nm) in traditional heat transfer fluid. The present experiment was conducted aiming at investigating the forced heat transfer characteristics of aqueous copper (Cu) nanofluid at varying concentration of Cu nano-particles in different flow regimes (300minar and turbulent flow with increasing the concentration. Especially, the enhancement rate increases dramatically in laminar flow regime, for instance, the heat transfer coefficient of Cu/water nanofluid increases by two times at around Re=2 000 compared with that of base fluid water, and averagely increases by 62% at 1% volume fraction. However, the heat transfer coefficient of Cu/water decreases sharply in the transition flow regime. Furthermore, it has the trend that the heat transfer coefficient displays worse with increasing the concentration.

关键词： nanofluid heat transfer characteristic circular tube metallic particles

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

Characterizing pressure fluctuation into single-loop oscillating heat pipe

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Journal of Central South University 2012年第9期19卷 2578-2583页

作者： PARK Yong-ho Md.Riyad Tanshen Md.J.Nine CHUNG Han-shik jeong hyo-min Department of Mechanical Engineering Koje CollegeJangseungpoKojeGyeongnamKorea Department of Mechanical and Precision Engineering Gyeongsang National University 445 Inpyeong-dongTongyeongGyeongnam650-160Korea Department of Energy and Mechanical Engineering Institute of Marine IndustryGyeongsang National UniversityCheondaegukchi-Gil 38TongyeongGyeongnam650-160Korea

The pressure characteristics inside single loop oscillating heat pipe （OHP） having 4.5 mm inner diameter copper tube with the loop height of 440 mm were addressed. Distilled water was used as working fluid inside the OHP with different filling ratios of 40%, 60% and 80% of total inside volume. Experimental results show that the thermal characteristics are significantly inter-related with pressure fluctuations as well as pressure frequency. And the pressure frequency also depends upon the evaporator temperature that is maintained in the range of 60-96 ℃. Piezoresistive absolute pressure sensor （Model-Kistler 4045A5） was used to take data. The investigation shows that the filling ratio of 60% gives the highest inside pressure magnitude at maximum number of pressure frequency at any of set evaporator temperature and the lowest heat flow resistance is achieved at 60% filling ratio.

关键词： oscillating heat pipe pressure fluctuation heat flow resistance filling ratio

Liquid film falling behaviour on horizontal circular cylinder

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Journal of Central South University 2012年第5期19卷 1353-1358页

作者： CHUNG Han-shik K.Wusiman KIM Seong-soo B.Nasan H.Afrianto Hafizur Rehman CHOI Du-youl jeong hyo-min Department of Energy and Mechanical Engineering The Institute of Marine IndustryGyeongSang National UniversityTongYoungGyeongNam 650-160Korea Department of Mechanical and Precision Engineering GyeongSang National UniversityTongYoungGyeongNam 650-160Korea Fluid and Thermal Engineering Co. Ltd.GimHae-siGyungNam 621-843Korea

The flow pattern behaviour of falling liquid film over three horizontal cylinders was *** flows can take three forms:discrete droplets,individual jets,and continuous sheet,and special attention is paid to the effects of the physical properties and geometrical parameters of the first two forms(droplets and jets) because these forms are more important in heat-transfer behaviour and less research has been published for these forms,The flow modes and experimental results were successfully compared with previous experimental literatures,and also the effects of liquid flow rate,tube diameter,and tube spacing on departure site spacing,in both drop and jet modes,were evaluated in the low Galileo number and high viscosity fluid(cooking oil),to help developing criteria for determining falling film modes and their transitions,and to understand the heat transfer characteristics associated with each mode.

关键词： falling film flow mode cylinder

Blood transcriptomic markers associated with immune abnormalities and sleep quality

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Genes & Diseases 2024年第6期11卷 111-114页

作者： Sang-min Park hyo-jeong Ban minsung Lee Soo Yeon Kim Siwoo Lee Hee-jeong Jin College of Pharmacy Chungnam National UniversityDaejeon34134Republic of Korea Korean Medicine(KM)Data Division Korea Institute of Oriental MedicineDaejeon 34054Republicof Korea

The prevalence of sleep disorders is increasing worldwide,prompting greater efforts to understand the biological mechanisms underlying *** the growing interest in this area,a continuous transcriptome analysis for studying sleep quality is still *** study performed a regression analysis of the Pittsburgh sleep quality index(PsQ)from the blood transcriptome to identify marker genes associated with sleep quality.

关键词： sleep Blood prevalence

Investigation of prodromal features in metabolic syndrome based on transcriptome analysis

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Genes & Diseases 2023年第3期10卷 708-711页

作者： Sang-min Park Musun Park hyo-jeong Ban Su-Jin Baek Soo Yeon Kim Siwoo Lee Hee-jeong Jin Korean Medicine(KM)Data Division Korea Institute of Oriental MedicineDaejeon 34054Republic of Korea College of Pharmacy Chungnam National UniversityDaejeon 34134Republic of Korea

Metabolic syndrome(MetS)is a complex condition that significantly increases the risk of several diseases,including heart disease and *** with MetS show both pro-inflammatory and pro-thrombotic states;however,the state... 详细信息

关键词： diseases Metabolic Patients

The Study on Effect of Exhaust Performance According to Active Muffler Valve Spring as Followed Spring Constant

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Journal of Thermal Science 2002年第4期11卷 372-377页

作者： Seuk Cheun Choi Tae Woo Kong Han Shik Chung hyo min jeong Young Heung Chun Graduate School of Mechanical and Precision Engineering Gyeongsang National UniversityInpyeongdong 445 Tongyong Kyongnam 650-160Korea School of Transport Vehicle Engineering Gyeongsang National UniversityThe Institute of Marine IndustryInpyeongdong 445 Tongyong Kyongnam 650-160Korea

This study represents the influence on exhaust performance by active muffler valve *** main experimental parameters were engine speeds and torsion coil spring constants in the active *** the muffler valve spring has a low spring constant of k=0.75,the sound pressure level was low at the region of engine speed 2000 to 2500 r/min,and the velocity of exhaust gas was high at spring constant k=*** the engine speed was under 1500 r/min,the mean concentration of CO was high in case without muffler *** the engine speed in the range of 1600 to 2600 r/min with spring constant k=0.75,the mean HC concentration showed the lowest *** muffler valve,the temperature in the muffler was higher than the case with muffler *** research represented that the performance of the active muffler valve spring constant k=0.75 was higher than that without muffler valve and valve spring constant k=*** the three cases of experimental condition,with a spring constant k=0.75,0.70 and without muffler valve,the exhaust performance was high in case active muffler valve spring constant k=0.70.

关键词： active muffler torsion coil spring spring constant sound pressure level

Genome-wide DNA methylation profiling reveals candidate biomarkers and probable molecular mechanism of metabolic syndrome

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Genes & Diseases 2022年第4期9卷 833-836页

作者： Su-Jin Baek hyo-jeong Ban Sang-min Park Soo Yeon Kim Siwoo Lee Hee-jeong Jin KM Data Division Korea Institute of Oriental Medicine1672 Yuseong-daeroYuseong-guDaejeon 34054Republic of Korea

Although aberrant DNA methylation changes are significantly associated with the pathogenesis of many diseases,little is known about the molecular mechanisms underlying interactions between DNA methylation and gene expression in metabolic syndrome(MetS).The aim of this study was to identify biomarkers and molecular mechanisms regulated by DNA methylation in *** profiled genome-wide DNA methylation using the Infinium MethylationEPIC BeadChIP and characterized the transcriptome by RNA sequencing in our study population comprised of subjects with MetS(n=11)and controls(n=9).

关键词： diseases pathogenesis EPIC

Development of dilated cardiomyopathy with a long latent period followed by viral fulminant myocarditis:A case report

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World Journal of Clinical Cases 2022年第36期10卷 13451-13457页

作者： Seung Do Lee hyo Jin Lee Hye Ree Kim min Gyu Kang Kyehwan Kim jeong Rang Park Division of Cardiology Department of Internal MedicineGyeongsang National University School of Medicine and Gyeongsang National University HospitalJinju 52727South Korea

BACKGROUND The clinical course of acute myocarditis ranges from the occurrence of a few symptoms to the development of fatal fulminant ***,fulminant myocarditis causes clinical deterioration very rapidly and *** long-term prognosis of myocarditis is varied,and it fully recovers without leaving any special ***,even after recovery,heart failure may occur and eventually progress to dilated cardiomyopathy(DCM),which causes serious left ventricular *** the case of follow-up observation,no clear guidelines have been *** SUMMARY We report the case of a 21-year-old woman who presented with *** became hemodynamically unstable and showed sustained fatal arrhythmias with decreased heart *** was clinically diagnosed with fulminant myocarditis based on her echocardiogram and cardiac magnetic resonance *** 2 d,she was readmitted to the emergency department under cardiopulmonary resuscitation and received mechanical ventilation and extracorporeal membrane *** implantable cardioverter defibrillator was inserted for secondary *** recovered and was *** to being hospitalized for sudden cardiac function decline and arrhythmia,she had been well for 7 years without any *** was finally diagnosed with dilated *** DCM may develop unexpectedly in patients who have been cured of acute fulminant myocarditis and have been stable with a long period of ***,they should be carefully and regularly observed clinically throughout long-term follow-up.

关键词： Myocarditis Fulminant Dilated cardiomyopathy Outcome Remission Case report