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Fabrication of two-layer flexible copper clad laminate by electroless-Cu plating on surface modified polyimide

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中国有色金属学会会刊：英文版 2009年第4期19卷 970-974页

作者： Soo-Min HWANG jun-Hyung LIM Chang-Min LEE Eui-Cheol park jun-Hyuk CHOI Jinho JOO Hoo-Jeong LEE Seung-Boo junG School of Advanced Materials Science and Engineering Sungkyunkwan University

A flexible copper clad laminate(FCCL) was fabricated using electroless-and electro-Cu plating processes and the effects of pre-treatment time on the adhesion strength of the FCCL were evaluated based on interfacial *** neutralization and catalyst time were varied in the range of 0-20 min and 0.1-10 min,respectively,and the interfacial condition of the FCCL was characterized by atomic force microscopy(AFM) and X-ray photoelectron spectroscopy(XPS).It is observed that the peel strength increases significantly as the neutralization and catalyst time *** strength as high as 7.2-7.3 N/cm is obtained as the neutralization and catalyst time increase up to 20 min and 10 min,respectively,which is comparable to the strength achieved by the conventional laminating and sputtering *** improvements are probably due to an increase in the surface roughness of polyimide(PI),the activated surface condition,and the adsorption of palladium ions/atoms(Pd) on the PI surface which act as nucleation sites for Cu.

关键词：聚酰亚胺表面改性化学制备层压板铜电镀铜箔软性 X射线光电子能谱

Fabrication of 3D Printed PCL/PEG Polyblend Scaffold Using Rapid Prototyping System for Bone Tissue Engineering Application

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Journal of Bionic Engineering 2018年第3期15卷 435-442页

作者： Su A park Sang Jin Lee Ji Min Seok jun Hee Lee Wan Doo Kim Il Keun Kwon Department of Nature-Inspired Nanoconvergence Systems Korea Institute of Machinery and Materials 156 Gajeongbuk-ro Yuseong-gu Daejeon 34103 Republic of Korea Department of Dental Materials School of Dentistry Kyung Hee University 26 Kyungheedae-ro Dongdaemun-gu Seou102447 Republic of Korea

Three-dimensional （3D） printing is a novel process used to manufacture bone tissue engineered scaffolds. This process allows for easy control of the architecture at the micro structure. However, the scaffold properties are typically limited in terms of cellular activity at the scaffold surface due to the printed materials properties. In this study, we developed a polycaprolactone （PCL） blended with polyethylene glycol （PEG） 3D printed scaffold using a rapid prototyping system. The manufactured scaffolds were then washed out to form small pores on the surface in order to improve the scaffolds hydrophilicity. We analyzed the resultant material by using Scanning Electron Microscopy （SEM）, water absorption, water contact angle, in vitro WST-1, and the Bradford assay. Additionally, cells incubated on the fabricated scaffolds were visualized by Confocal Laser Scanning Microscopy （CLSM）. The developed scaffolds exhibited small pores on the strand surface which served to increase hydrophilicity as well as improve cellular proliferation and increase total protein content. Our findings suggest that the presence of small pores on the scaffolds can be used as an effective tool for improving implant cellular interaction. This research indicates that these modified scaffolds can be considered useful for bone tissue engineering applications to improve human health.

关键词： polycaprolactone polyethylene glycol polyblend 3D printing porosity bone tissue engineering

Manipulation of vertical fence wake using passive vortex generators

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排灌机械工程学报 2014年第5期32卷 369-372,377页

作者： Kim Hyoung-Bum Kim Seoung-jun Tu Xin-Cheng park Seung-Ha Kim Seoung-jun Tu Xin-Cheng park Seung-Ha Research Center for Aircraft Parts Technology Gyeongsang National University School of Mechanical Engineering Gyeongsang National University R & D Center DongHwa Entec School of Mechanical Engineering Gyeongsang National University Jinju 660 -701 S. Korea R & D Center DongHwa Entee Busan 618-230 S. Korea

The effect of streamwise vortices generated from passive vortex generators was investigated to manipulate the separation bubble behind the vertical fence. The experiments were carried out in a circulating water channel and the velocity fields were measured using 2D and stereoscopic PIV *** distance between the vortex generator and fence and the effect of the Reynolds number were investigated. In addition,the effect of boundary layer thickness was also investigated. The averaged recirculation lengths were compared with that of uncontrolled fence flow. The results showed the oscillatory variation of recirculation region appeared under the existence of vortex generators. The reduction of the separation bubble became larger when the fence was submerged in the thick boundary layer with increasing the distance between the generator and fence. When the boundary layer is thin,vortex generator can only suppress the separation bubble under the specific condition.

关键词： vortex generator flow separation stereoscopic PIV experiment

Non-Jumping Take off Performance in Beetle Flight （Rhinoceros Beetle Trypoxylus dichotomus）

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Journal of Bionic Engineering 2014年第1期11卷 61-71页

作者： Tien Van Truong Tuyen Quang Le Hoon Cheol park Kwang Joon Yoon Min jun Kim Doyoung Byun Department of Aerospace and Information Engineering Konkuk University Seoul South Korea Department of Mechanical Engineering National University of Singapore Singapore KoreaInstitute of Ocean Science and Technology PO Box 29 Ansan 425-600 South Korea Department of Advanced Technology Fusion Konkuk University Seoul South Korea Department of Mechanical Engineering and Mechanics Drexel University Philadelphia PA 19104 USA Department of Mechanical Engineering Sungkyunkwan University Suwon South Korea

In recent decades, the take-off mechanisms of flying animals have received much attention in insect flight initiation. Most of previous works have focused on the jumping mechanism, which is the most common take-off mechanism found in flying animals. Here, we presented that the rhinoceros beetle, Trypoxylus dichotomus, takes offwithout jumping. In this study, we used 3-Dimensional （3D） high-speed video techniques to quantitatively analyze the wings and body kinematics during the initiation periods of flight. The details of the flapping angle, angle of attack of the wings and the roll, pitch and yaw angles of the body were investigated to understand the mechanism of take-off in T. dichotomus. The beetle took off gradually with a small velocity and small acceleration. The body kinematic analyses showed that the beetle exhibited stable take-off. To generate high lift force, the beetle modulated its hind wing to control the angle of attack; the angle of attack was large during the upstroke and small during the downstroke. The legs of beetle did not contract and strongly release like other insects. The hind wing could be con- sidered as a main source of lift for heavy beetle.

关键词： take-oft non-jumping mechanism rhinoceros beetle kinematics

In?uence of Carbon Equivalent Value on the Weld Bead Bending Properties of High-Strength Low-Alloy Steel Plates

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Journal of Materials Science & Technology 2017年第4期33卷 321-329页

作者： Ki Hyuk Kim In jun Moon Ki Won Kim Ki Bong Kang Byung Gyu park Kwang Seok Lee R&D Center of Dongkuk Steel Mill Co. Ltd Pohang 790-729 South Korea Korea Institute of Materials Science Implementation Research Division Materials Deformation Department 797 Changwondaero Changwon Gyeongnarn642-831 South Korea

The contribution of chemical compositions in terms of carbon equivalent value（CEV） on impending crack propagation during weld bead bend tests（WBBTs） was studied with five different high-strength lowalloy steel plates that underwent different rolling processes. The test showed that cracks developed at the weld joint, easily passed through the coarse-grain heat-affected zone（CGHAZ）, and finally were arrested within the heat-affected zone（HAZ）. An apparent decrease in the average crack length, which consequently indicated improvement in crack arrestability, was found with decreasing CEV. In addition,the relatively fine microstructure in the HAZ of low-CEV steel plates helped in preventing the crack from further propagation. Special emphasis was placed on the empirical expectation of critical CEV above which WBBT might fail.

关键词： Mechanical characterization Steel Welding Fracture Crack arrestability against bending

EXPERIMENTAL ESTIMATION OF A SCALING EXPONENT FOR TIP VORTEX CAVITATION VIA ITS INCEPTION TEST IN FULL-AND MODEL-SHIP

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Journal of Hydrodynamics 2012年第5期24卷 658-667页

作者： LEE Jeung-Hoon junG Jae-Kwon LEE Kyung-jun HAN Jae-Moon park Hyung-Gil SEO Jong-Soo Samsung Ship Model Basin(SSMB) Marine Research InstituteSamsung Heavy IndustriesScience TownDaejeon 305-380Korea

Tip vortex cavitation noise of marine propeller became primary concems to reduce hazardous environmental impacts from commercial ship or to keep the underwater surveillance of naval ships. The investigations of the tip vortex and its induced noise are normally conducted through the model test in a water cavitation tunnel. However the Reynolds number of model-test is much smaller than that of the full-scale, which subsequently results in the difference of tip vortex cavitation inception. Hence, the scaling law between model- and full-scales needs to be identified prior to the prediction and assessment of propeller noise in full scale. From previous researches, it is generally known that the incipient caivtation number of tip vortex can be represented as a power of the Reynolds number. However, the power exponent for scaling, which is the main focus of this research, has not been clearly studied yet. This paper deals with the estimation of scaling exponent based on tip vortex cavitation inception test in both full- and model-scale ships. Acoustical measurements as well as several kind of signal processing technique for an inception criterion suggest the scaling exponent as 0.30. The scaling value proposed in this study shows slight difference to the one of most recent research. Besides, extrapolation of model-ship noise measurement using the proposed one predicts the full-scale noise measurement with an acceptable discrepancy.

关键词： tip vortex cavitation underwater radiated noise scaling exponent

Prevalence of premature ejaculation in young and middle-aged men in Korea： a multicenter intemet-based survey from the Korean Andrological Society

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Asian Journal of Andrology 2010年第6期12卷 880-889页

作者： Hyun jun park Jong Kwan park Kwangsung park Sung Won Lee Sae-Woong Kim Dae Yul Yang DU Geon Moon Kweon-Sik Min Ki-Hak Moon Sang-Kuk Yang Jae Seog Hyun Nam Cheol park Deparment of Urology Pusan National University School of medicine Busan 602739 Korea Deparment of Urology Chonbuk National University Medical School Jeonju 561712 Korea Deparment of Urology Chonnam National University Medical School Gwangju 501746 Korea Deparment of Urology Sungkyunkwan Univer＆ty School of Medicine Seou1135 710 Korea Deparment of Urology Catholic University College of Medicine Seoul 137701 Korea Deparment of Urology Hallym University College of Medicine Seoul 13 7701 Korea Deparment of Urology Korea University College of Medicine Seoul 152703 Korea Deparment of Urology lnje University College of Medicine Busan 614735 Korea Deparment of Urology Yeungnam University College of Medicine Daegu 705717 Korea Deparment of Urology Konkuk University School of Medicine Chungju 380704 Korea Deparment of Urology Gyeongsang National University School of Medicine Jinju 660702 Korea

In this study, we aimed to investigate the prevalence and perception of premature ejaculation （PE） in young and middle-aged Korean men. The study was conducted using an Internet-assisted questionnaire. A total of 2 037 Korean male adults, aged 20 years or older, were randomly sampled based on age and residency. The questionnaire developed by the PE Study Group of the Korean Andrological Society includes four categories （overall sexual function, symptoms, distress and treatment） with a total of 16 questions. For each question, symptoms were evaluated by a scale ranging from 0 to 10. Intravaginal ejaculation latency time was ‘5-10 min＇ in 38.6%, followed by ‘longer than 10 min＇ in 2919%, ‘2-5 min＇ in 23.6%, ‘1-2 min＇ in 5.4% and ‘shorter than 1 min＇ in 2.5%. In our series, 27.5% of respondents reported having PE. Control over ejaculation within a recent 3-month period was 6.2 points on average. Respondent complaints of PE-related stress averaged 7.1 points and stress-related complaints from sexual partners averaged 7.1 points. The effect of PE on sexual life was 6.8 points. Of the respondents determined as having PE, 42.6% responded that they were inclined to receive treatment. Results from this study suggest that the prevalence of PE diagnosed by the respondent on his own was approximately 27.5% in young and middle-aged men in Korea. PE-related stress had a significant effect on the stress, sexual activity and quality of life of the respondent and his sexual partner.

关键词： epidemiology premature ejaculation questionnaire sexual dysfunction

Oral chemotherapy for second-line treatment in patients with gemcitabine-refractory advanced pancreatic cancer

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World Journal of Gastrointestinal Oncology 2019年第11期11卷 1021-1030页

作者： Se jun park Hyunho Kim Kabsoo Shin Myung Ah Lee Tae Ho Hong Division of Medical Oncology Department of Internal MedicineThe Catholic University of KoreaSeoul St.Mary’s HospitalSeoul 100744South Korea Department of General Surgery The Catholic University of KoreaSeoul St.Mary’s HospitalSeoul 100744South Korea

BACKGROUND There is no standard therapy for second-line treatment of gemcitabine-refractory pancreatic cancer patients with poor performance status.A combination of chemotherapy drugs 5-fluorouracil(5-FU),leucovorin,irinotecan,and oxaliplatin(FOLFIRINOX)or 5-fluorouracil/leucovorin plus nanoliposomal irinotecan can be considered as second-line treatment for such patients;however,due to toxicity,none of the regimens are recommended for patients with poor *** or S-1 has relatively low toxicity and can be considered a treatment option for gemcitabine-refractory pancreatic *** To investigate the efficacy and toxicity of oral chemotherapy as second-line treatment in patients with pancreatic *** Patients who had progressive disease after first-line gemcitabine-based chemotherapy were retrospectively analyzed between January 2011 and December *** were treated with capecitabine or S-1 as the second-line *** was administered as a 2500 mg/m2 divided dose on days 1-14,followed by a 1-wk rest.S-1 was taken orally based on the patient’s body surface area for 28 d,followed by 2-wk of ***-free survival and overall survival were used to compare efficacy of capecitabine and *** Of the 81 patients,41 were treated with capecitabine and 40 with *** median time to treatment failure in both groups was 1.5 mo(P=0.425).The objective response rate was similar in the two groups:9.8%with capecitabine and 2.5%with S-1(P=0.359).Median progression-free survival was longer in the S-1 group than in the capecitabine group(S-12.7 mo,capecitabine 2.0 mo,P=0.003).There was no significant difference in the median overall survival between the capecitabine and S-1 groups(4.3 mo vs 5.0 mo,P=0.092).Grade 3 or 4 hand-foot syndrome was significantly more common in the capecitabine group than in the S-1 group(14.6%vs 0%,P=0.026).CONCLUSION Capecitabine or S-1 can be used as a second-line treatment for patients with advanc

关键词： Pancreatic cancer Gemcitabine-refractory Capecitabine S-1 Second-line treatment

Applications of scaffolds:Tools for enhancing the immunomodulation of mesenchymal stromal cells

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BIOCELL 2022年第6期46卷 1439-1443页

作者： OK-HYEON KIM EUN RAN KIM jun HYUNG park HYUN junG LEE Department of Anatomy and Cell Biology College of MedicineChung-Ang UniversitySeoul06974South Korea Department of Global Innovative Drugs Graduate School of Chung-Ang UniversitySeoul06974South Korea Severance Biomedical Science Institute Yonsei Biomedical Research InstituteCollege of MedicineYonsei UniversitySeoul03722South Korea

Exogenously delivered mesenchymal stromal cells(MSCs)are therapeutically beneficial owing to their paracrine effect;they secrete various cytokines,nucleic acids,and *** bioengineering techniques can help MSC cultures to release secretomes by providing stem cell niche-like conditions(both structurally and functionally).Various scaffolds mimic the natural extracellular matrix(ECM)using both natural and synthetic polymers,providing favorable environments for MSC proliferation and *** on material properties,either topographically or elastically structured scaffolds can be ***-dimensional scaffolds have tunable substrate rigidities and structures,aiding MSC *** ECM-derived hydrogels are similar to the natural ECM,thus improving the paracrine effects of ***,we discuss recent research on the application of scaffolds to maximize the immunomodulatory function of MSCs.

关键词： Extracellular matrix(ECM) Immunomodulation Mesenchymal stromal cells(MSCs) Scaffolds Stem cell niche