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An Experimental Study of Condensation Heat Transfer in Sub-Millimeter Rectangular Tubes

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Journal of Thermal Science 2004年第4期13卷 350-357页

作者： jeong Seob SHIN Moo Hwan kim Department of Mechanical Engineering POSTECH Pohang KoreaDepartment of Mechanical Engineering POSTECH Pohang Korea

The characteristics of local heat transfer and pressure drops were experimentally investigated using condensing R134a two-phase flow, in single rectangular tubes, with hydraulic diameter of 0.494, 0.658, and 0.972 mm. New experimental techniques were used to measure the in-tube condensation heat transfer coefficient especially for the low heat and mass flows. Tests were performed for a mass flux of 100, 200, 400, and 600 kg/m2s, a heat flux of 5 to 20 kW/m2, and a saturation temperature of 40℃. In this study, effect of heat flux, mass flux, vapor qualities, and hydraulic diameter on flow condensation were investigated and the experimental local condensation heat transfer coefficients and frictional pressure drop are shown. The experimental data of condensation Nusselt number are compared with previous correlations, most of which are proposed for the condensation of pure refrigerant in a relatively large inner diameter round tubes.

关键词： condensation hydraulic diameter rectangular in-tube multiphase flow.

Exploring ideal operative time for best outcomes in gastric cancer surgery:A multi-institutional study based on KLASS-07 database

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Chinese Journal of Cancer Research 2023年第6期35卷 660-674页

作者： Shin-Hoo Park Ye-Rim Shin Hoon Hur Chang Min Lee Jae Seok Min Seung Wan Ryu Hyun Dong Chae Oh jeong Chang-In Choi Kyo-Young Song Ho Goon kim Ye Seob Jee Kwang Hee kim jeong Goo kim Kyung Sook Yang Hua Huang Sungsoo Park Division of Foregut Surgery Korea University College of MedicineSeoul 02841Republic of Korea Division of Foregut Surgery Korea University Anam HospitalSeoul 02841Republic of Korea Department of Surgery Ajou University School of MedicineSuwon 16499Republic of Korea Division of Foregut Surgery Korea University Ansan HospitalAnsan 15355Republic of Korea Department of Surgery Dongnam Institute of Radiological and Medical SciencesCancer CenterBusan 46033Republic of Korea Department of Surgery Keimyung University Dongsan Medical CenterDaegu 41931Republic of Korea Department of Surgery Catholic University of Daegu School of MedicineDaegu 42472Republic of Korea Department of Surgery Chonnam National University Medical SchoolHwasun 58128Republic of Korea Department of Surgery Pusan National University HospitalPusan 49241Republic of Korea Department of Surgery Catholic University of Seoul St Mary’s HospitalSeoul 06591Republic of Korea Department of Surgery Chonnam National University Medical SchoolGwangju 61469Republic of Korea Department of Surgery Dankook University College of MedicineCheonan 31116Republic of Korea Department of Surgery Busan Paik HospitalInje UniversityBusan 14905Republic of Korea Department of Surgery Daejeon St.Mary’s HospitalCollege of Medicinethe Catholic University of KoreaDaejeon 34943Republic of Korea Department of Biostatistics Korea University College of MedicineSeoul 02841Republic of Korea Department of Gastric Cancer and Soft Tissue Sarcoma Fudan University Shanghai Cancer CenterShanghai 200433China Department of Oncology Shanghai Medical CollegeFudan UniversityShanghai 200433China

Objective:While a rushed operation can omit essential procedures,prolonged operative time results in higher ***,the optimal operative time range remains *** study aimed to estimate the ideal operative time range and evaluate its applicability in laparoscopic cancer ***:A prospectively collected multicenter database of 397 patients who underwent laparoscopic distal gastrectomy were retrospectively *** ideal operative time range was statistically calculated by separately analyzing the operative time of uneventful ***,intraoperative and postoperative outcomes were compared among the shorter,ideal,and longer operative time ***:The statistically calculated ideal operative time was 135.4-165.4 *** longer operative time(LOT)group had a lower rate of uneventful,perfect surgery than the ideal or shorter operative time(IOT/SOT)group(2.8%vs.8.8%and 2.2%vs.13.4%,all P<0.05).Longer operative time increased bleeding,postoperative morbidities,and delayed diet and discharge(all P<0.05).Particularly,an uneventful,perfect surgery could not be achieved when the operative time exceeded 240 *** of ideal time range,SOT group achieved the highest percentage of uneventful surgery(13.4%),which was possible by surgeon's ability to retrieve a higher number of lymph nodes and perform≥150 gastrectomies ***:Operative time longer than the ideal time range(especially≥240 min)should be *** the essential operative procedure were faithfully conducted without compromising oncological safety,an operative time shorter than the ideal range leaded to a better *** to minimize operative time should be attempted with sufficient surgical experience.

关键词： Operative time laparoscopic surgery gastric cancer gastrectomy morbidity

Analysis and Experiment on the Steering Control of a Water-running Robot Using Hydrodynamic Forces

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Journal of Bionic Engineering 2017年第1期14卷 34-46页

作者： HyunGyu kim Kyungmin jeong TaeWon Seo School of Mechanical Engineering Yeungnam University Gyeongsan 712-749 Republic of Korea Nuclear Convergence Technology Division Korea Atomic Energy. Research Institute Daejeon 305-353 Republic of Korea

Steering is important for the high maneuverability of mobile robots. Many studies have been performed to improve the maneuverability using a tail. The aim of this research was to verify the performance of a water-running robot steering on water using a tail. Kinematic analysis was performed for the leg mechanism and the interaction forces between the water and the feet to calculate the propulsive drag force of the water. This paper suggests a simplified planar two-link rigid body model to determine the dynamic performance of the robotic platform with respect to the effect of the tail＇s motion. Simulations based on a dynamic model were performed by applying a range of motions to the tail. In addition, a simulation with a Bang-bang controller was also performed to control the main frame＇s yawing locomotion. Finally, an experiment was conducted with the controller, and the simulation and experimental results were compared. These results can be used as a guideline to develop a steerable water-running robot.

关键词： basilisk lizard water-running robot steering Static Tail (ST) Dynamic Tail (DT) planar two-link rigid body

IRG1 induced by heme oxygenase- 1/carbon monoxide inhibits LPS-mediated sepsis and pro-inflammatory cytokine production

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Cellular & Molecular Immunology 2016年第2期13卷 170-179页

作者： Md Jamal Uddin Yeonsoo Joe Seul-Ki kim Sun Oh jeong Stefan W Ryter Hyun-Ock Pae hun Taeg Chung School of Biological Sciences University of Ulsan Korea Department of Microbiology and Immunology Wonkwang University School of Medicine Korea Joan and Sanford I. Weill Department of Medicine New York-Presbyterian Hospital Weill Cornell Medical College New York USA

The immunoresponsive gene 1 （IRG 1） protein has crucial functions in embryonic implantation and neurodegeneration. IRG1 promotes endotoxin tolerance by increasing A20 expression in macrophages through reactive oxygen species （ROS）. The cytoprotective protein heme oxygenase-1 （HO-1）, which generates endogenous carbon monoxide （CO）, is expressed in the lung during Lipopolysaccharide （LPS） tolerance and cross tolerance. However, the detailed molecular mechanisms and functional links between IRG1 and HO-1 in the innate immune system remain unknown. In the present study, we found that the CO releasing molecule-2 （CORM-2） and chemical inducers of HO- 1 increased I RG 1 expression in a time- and dose-dependent fashion in RAW264.7 cells. Furthermore, inhibition of HO-1 activity by zinc protoporphyrin IX （ZnPP） and HO-1 siRNA significantly reduced expression of IRG1 under these conditions. In addition, treatment with CO and HO-1 induction significantly increased A20 expression, which was reversed by ZnPP and HO-1 siRNA. LPS-stimulated TNF-a was significantly decreased, whereas IRG1 and A20 were increased by CORM-2 application and HO-1 induction, which in turn were abrogated by ZnPP. Interestingly, siRNA against IRG1 and A20 reversed the effects of CO and HO-1 on LPS-stimulated TNF-a production. Additionally, CO and HO-1 inducers significantly increased IRG1 and A20 expression and downregulated TNF-a production in a LPS-stimulated sepsis mice model. Furthermore, the effects of CO and HO-1 on TNF-α production were significantly reversed when ZnPP was administered. In conclusion, CO and HO-1 induction regulates IRG1 and A20 expression, leading to inhibition of inflammation in vitroand in an in vivomice model.

关键词： A2O anti-inflammatory effects carbon monoxide HO-1 IRG1

Effects of foundation damage and water-level change on vibration modal parameters of gravity-type caisson structure

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Science China(Technological Sciences) 2015年第2期58卷 316-329页

作者： LEE So-Young kim jeong-Tae Department of Ocean Engineering Pukyong National University

In this paper,the effects of foundation damage and water-level change on vibration characteristics of gravity-type caisson structure are examined by analyzing modal parameters extracted from output-only *** achieve the objective,the following approaches are ***,vibration response analysis methods are selected to estimate power spectral density and modal parameters such as natural frequency,damping ratio and mode shape of a lab-scale caisson structural ***,vibration tests on the lab-scale caisson system are performed under a series of test scenarios which include three water-level changes and three damage ***,experimental modal parameters corresponding to the damaging cases as well as the water level cases are extracted by frequency domain decomposition method and stochastic subspace identification ***,the effects of the water-level variation and foundation damage on the extracted modal parameters are examined to assess the feasibility of the vibration-based damage detection in gravity-type caisson structures under water-level uncertainty.

关键词：振动模态参数水位变化沉箱结构重力式基础伤害实验室规模试验模态参数

Preclinical Long-term Magnetic Resonance Imaging Study of Silymarin Liver-protective Effects

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Journal of Clinical and Translational Hepatology 2022年第6期10卷 1167-1175页

作者： Yeon Ji Chae Hwon Heo Chul-Woong Woo Sang-Tae kim Jae-Im Kwon Monica Young Choi Yu Sub Sung Kyung Won kim jeong Kon kim Yoonseok Choi Dong-Cheol Woo Department of Convergence Medicine Asan Medical CenterUniversity of Ulsan College of MedicineSeoulRepublic of Korea Convergence Medicine Research Center Asan Institute for Life SciencesAsan Medical CenterSeoulRepublic of Korea Clinical Research Center Asan Medical CenterSeoulRepublic of Korea Department of Radiology Asan Medical CenterUniversity of Ulsan College of MedicineSeoulRepublic of Korea Medical Research Institute Gangneung Asan HospitalGangneung-siGangwon-doRepublic of Korea

Background and Aims:Efficacy evaluations with preclini-cal magnetic resonance imaging(MRI)are uncommon,but MRI in the preclinical phase of drug development provides information that is useful for longitudinal *** study aim was to monitor the protective effectiveness of silymarin with multiparameter MRI and biomarkers in a thioacetamide(TAA)-induced model of liver injury in *** analysis was conducted to assess compare the monitoring of liver function by MRI and ***-ods:TAA was injected three times a week for 8 weeks to generate a disease model(TAA group).In the TAA and sily-marin-treated(TAA-SY)groups,silymarin was administered three times weekly from week *** images were acquired at 0,2,4,6,and 8 weeks in the control,TAA,and TAA-SY ***:The area under the curve to maximum time(AUCtmax)and T_(2)*values of the TAA group decreased over the study period,but the serological markers of liver abnormality increased significantly more than those in the control *** the TAA-SY group,MRI and serological biomarkers indicated attenuation of liver function as in the TAA ***,pattern changes were observed from week 6 to comparable levels in the control group with si-lymarin *** correlations between either AUCtmax or T_(2)*values and the serological biomarkers were ***:Silymarin had hepatoprotective effects on TAA-induced liver injury and demonstrated the usefulness of multiparametric MRI to evaluate efficacy in preclinical studies of liver drug development.

关键词： Liver fibrosis Magnetic resonance imaging Silymarin T1-weight-ed dynamic contrast-enhanced T_(2)*

Rapid crystallization-driven high-efficiency phase-pure deep-blue Ruddlesden–Popper perovskite light-emitting diodes

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Advanced Photonics 2023年第1期5卷 8-18页

作者： Gyumin Jang Hyowon Han Sunihl Ma Junwoo Lee Chan Uk Lee Wooyong jeong Jaehyun Son Dongki Cho Ji-Hee kim Cheolmin Park Jooho Moon Yonsei University Department of Materials Science and EngineeringSeoulRepublic of Korea Sungkyunkwan University Department of Energy ScienceSuwonRepublic of Korea Institute for Basic Science Center for Integrated Nanostructure PhysicsSuwonRepublic of Korea

Perovskite light-emitting diodes(PeLEDs)are considered as promising candidates for nextgeneration solution-processed full-color ***,the external quantum efficiencies(EQEs)and operational stabilities of deep-blue(3 is hampered completely,so that phase-pure 2D-RPP films with bandgaps suitable for deep-blue PeLEDs can be obtained *** uniquely developed rapid crystallization method also enables formation of randomly oriented 2D-RPP crystals,thereby improving the transfer and transport kinetics of the charge ***,high-performance deep-blue PeLEDs emitting at 437 nm with a peak EQE of 0.63%are successfully *** color coordinates are confirmed to be(0.165,0.044),which match well with the Rec.2020 standard blue gamut and have excellent spectral stability.

关键词： Ruddlesden–Popper perovskite rapid crystallization deep-blue light-emitting diodes phase purity randomly oriented crystals

Evaluation of the performance of a soft X-ray charger for the bipolar charging of nanoparticles

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Particuology 2015年第1期13卷 165-169页

作者： Young hun Yoon Choonkeun Bong Dae Seong kim Department of Integrated Environmental Systems Pyeongtaek University GreenSolus Co. Global Frontier Center for Multiscale Energy Systems Seoul National University

The use of soft X-rays in a neutralizer represents an alternative technique that could replace conventional radioactive sources. In this study, we evaluated the charging characteristics of a soft X-ray aerosol neu- tralizer. In addition, the results from the evaluation of the soft X-ray charger were compared with results obtained using a neutralizer incorporating an 241 Am radioactive source. The tandem differential mobility analyzer technique was used previously to determine the size-dependent positive, negative, and neutral charge fractions of a soft X-ray neutralizer. This technique was used to show that the neutral fractions obtained using the soft X-ray charger agreed well with the predictions of bipolar diffusion charging the- ory, and that the soft X-ray charger could be used as a neutralizer for a scanning mobility particle sizer system.

关键词： Soft X-ray Neutralizer Bipolar charger Nanoparticle TDMA

Densification simulation of compacted Al powders using multi-particle finite element method

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中国有色金属学会会刊：英文版 2009年第B9期19卷 68-75页

作者： Kyung-hun LEE Jung-Min LEE Byung-Min kim School of Mechanical Engineering Pu san National University

The powder compaction simulations were performed to demonstrate deformation behavior of particles and estimate the effect of different punch speeds and particle diameters on the relative density of powder by a multi-particle finite element model(MPFEM). Individual particle discretized with a finite element mesh allows for a full description of the contact mechanics. In order to verify the reliability of compaction simulation by MPFEM, the compaction tests of porous aluminum with average particle size of 20 μm and 3 μm were performed at different ram speeds of 5, 15, 30 and 60 mm/min by MTS servo-hydraulic tester. The results show that the slow ram speed is of great advantage for powder densification in low compaction force due to sufficient particle rearrangement and compaction force increases with decrease in average particle size of aluminum.

关键词：粉末压实粉末粒子多孔铝有限元法模拟致密化平均粒径有限元模型