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Optimal Wing Rotation Angle by the Unsteady Blade Element Theory for Maximum Translational Force Generation in Insect-mimicking Flapping-wing Micro Air Vehicle

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Journal of Bionic Engineering 2016年第2期13卷 261-270页

作者： Loan Thi Kim Au Hoang Vu Phan Hoon cheol park Department of Advanced Technology Fusion Konkuk University Seoul 143-701 South Korea

This paper provides a parametric study to obtain the optimal wing rotation angle for the generation of maximum transla- tional force in an insect-mimicking Flapping-Wing Micro Air Vehicle （FWMAV） during hovering. The blade element theory and momentum theory were combined to obtain the equation from which the translational aerodynamic force could be esti- mated. This equation was converted into a non-dimensional form, so that the effect of normalized parameters on the thrust coefficient could be analyzed. The research showed that the thrust coefficient for a given wing section depends on two factors, the rotation angle of the wing section and the ratio of the chord to the travel distance of the wing section in one flapping cycle. For each ratio that we investigated, we could arrive at an optimal rotation angle corresponding to a maximum thrust coefficient. This study may be able to provide guidance for the FWMAV design.

关键词： FWMAV optimal rotation angle parametric study blade element theory momentum theory

Combination of Korean Red Ginseng Extract and Hydrogen-Rich Water Improves Spermatogenesis and Sperm Motility in Male Mice

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Chinese Journal of Integrative Medicine 2020年第5期26卷 361-369页

作者： Ja Yoon Ku Min Jung park Hyun Jun park Nam cheol park Bo Sun Joo Department of Urology Pusan National University HospitalPusan National University School of MedicineBusan(49241)Republic of Korea Biomedical Research Institute Pusan National University HospitalBusan(49241)Republic of Korea The Korea Institute for Public Sperm Bank Busan(49241)Republic of Korea

Objective: To investigate the effect of hydrogen-rich Korean Red Ginseng(KRG) water(HRGW) mixture on the spermatogenesis and sperm motility of mice of different ages. Methods: Eighty young(3 month-old) and aged(12 month-old) male mice were randomly assigned to 4 groups(n=10 per group) including control group, hydrogen-rich water(HRW) group(10 m L/kg daily), KRG group(50 mg/kg daily) and HRGW group(10 m L/kg HRW and 50 mg/kg KRG daily) by an oral zoned needle for 4 weeks. Sperm count and motility were measured using sperm suspension released from cauda epididymis. Serum follicle stimulating hormone(FSH), luteinizing hormone(LH), testosterone, and reactive oxygen species(ROS) in serum have also been estimated. Tubular changes were examined through histological hematoxylin and eosin staining. Expression of antioxidation(PPx3, PPx4, GSTm5 and GPx4), spermatogenesis(inhibin-α, neptin-2 and CREM), antiaging(SIRT1 and SIRT2), and angiogenesis [visfatin and vascular endothelial growth factor(VEGF)] related genes were examined through realtime polymerase chain reaction. Results: HRW and KRG treatment stimulated spermatogenesis followed by increasing sperm production and sperm motility(P<0.05). These effects were strengthened synergistically by a HRGW mixture(P<0.05 or P<0.01). HRGW greatly increased the expressions of antioxidation, antiaging, spermatogenesis related genes and VEGF especially in aged mice(P<0.05). Serum testosterone and FSH levels also increased, while serum ROS level decreased(all P<0.05). Conclusion: HRGW increases sperm production and motility by enhancing antioxidation and stimulating spermatogenesis and sex hormone production, particularly in aged mice.

关键词： aging ginseng infertlit mineral waters sperm mtility

Atomic layer deposition of an Al_2O_3 dielectric on ultrathin graphite by using electron beam irradiation

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Journal of Semiconductors 2012年第9期33卷 34-37页

作者：蒋然孟令国张锡健 Hyung-Suk Jung cheol seong Hwang School of Physics Shandong UniversityJinan 250100China Department of Materials Science and Engineering Seoul National UniversitySeoul 151-747Korea

Atomic layer deposition ofan Al2O3 dielectric on ultrathin graphite is studied in order to investigate the integration of a high k dielectric with graphite-based substrates. Electron beam irradiation on the graphite surface is followed by a standard atomic layer deposition ofAl2O3. Improvement of the Al2O3 layer deposition morphology was observed when using this radiation exposure on graphite. This result may be attributed to the amorphous change of the graphite layers during electron beam irradiation.

关键词： Al2O3 high k atomic layer deposition graphene

Clinical features of HBs Ag seroclearance in hepatitis B virus carriers in South Korea: A retrospective longitudinal study

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World Journal of Gastroenterology 2016年第44期22卷 9836-9843页

作者： Young Min park seong Gyu Lee Hepatology Center Department of Internal Medicine and Biomedical Research Center Bundang Jesaeng General Hospital epartment of Laboratory Medicine Bundang Jesaeng General Hospital

AIM To investigate the characteristic features of hepatitis B surface antigen(HBs Ag) seroclearance among Korean hepatitis B virus(HBV) *** Carriers with HBs Ag seroclearance were selected by analyzing longitudinal data collected from 2003 to 2015. The period of time from enrollment to the negative conversion of HBs Ag(HBs Ag-NC) was compared by stratifying various factors, including age, sex, hepatitis B e antigen(HBe Ag), HBV DNA, sequential changes in the signal-to-cutoff ratio of HBs Ag(HBs Ag-SCR), as measured by qualitative HBs Ag assay, and chronic liver disease on ultrasonography(US-CLD). Quantification of HBV DNA and HBs Ag(HBs Ag-QNT) in the serum was performed by commercial *** Among the 1919 carriers, 90(4.7%) exhibited HBs AgNC at 6.2 ± 3.6 years after registration, with no differences observed among the different age groups. Among these carriers, the percentages of those with asymptomatic liver cirrhosis(LC) and hepatocellular carcinoma(HCC) at registration were 31% and 7.8%, respectively. The frequency of HBs Ag-NC significantly differed according to the HBV DNA titer and US-CLD. HBe Ag influenced HBs Ag-NC in the 40-50 and 50-60 year age groups. HBs Ag-SCR < 1000 was correlated with an HBs Ag-QNT < 200 IU/m L. A gradual decrease in the HBs Ag-SCR to < 1000 predicted HBs Ag-NC. Six patients developed HCC after registration, including two before and four after HBs Ag-NC. The rate at which the patients developed new HCC after HBs Ag seroclearance was 4.8%. LC with excessive drinking and vertical infection were found to be risk factors for HCC in the HBs Ag-NC *** HCC surveillance should be continued after HBs Ag seroclearance. An HBs Ag-SCR < 1000 and its decrease in sequential testing are worth noting as predictive markers of HBs Ag loss.

关键词： Hepatocellular carcinoma Hepatitis B virus Hepatitis B Surface antigen HBs Ag Seroconversion Hepatitis B e antigen HBe Ag Liver cirrhosis

Radiologic evaluation of nonalcoholic fatty liver disease

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World Journal of Gastroenterology 2014年第23期20卷 7392-7402页

作者： Seung Soo Lee seong Ho park Department of Radiology and Research Institute of Radiology University of Ulsan College of MedicineAsan Medical CenterSeoul 138-736South Korea

Nonalcoholic fatty liver disease(NAFLD)is a frequent cause of chronic liver diseases,ranging from simple steatosis to nonalcoholic steatohepatitis(NASH)-related liver *** liver biopsy is still the gold standard for the diagnosis of NAFLD,especially for the diagnosis of NASH,imaging methods have been increasingly accepted as noninvasive alternatives to liver *** is a well-established and costeffective imaging technique for the diagnosis of hepatic steatosis,especially for screening a large population at risk of *** has a reasonable accuracy in detecting moderate-to-severe hepatic steatosis although it is less accurate for detecting mild hepatic steatosis,operator-dependent,and rather *** tomography is not appropriate for general population assessment of hepatic steatosis given its inaccuracy in detecting mild hepatic steatosis and potential radiation ***,computed tomography may be effective in specific clinical situations,such as evaluation of donor candidates for hepatic *** resonance spectroscopy and magnetic resonance imaging are now regarded as the most accurate practical methods of measuring liver fat in clinical practice,especially for longitudinal followup of patients with *** elastography and magnetic resonance elastography are increasingly used to evaluate the degree of liver fibrosis in patients with NAFLD and to differentiate NASH from simple *** article will review current imaging methods used to evaluate hepatic steatosis,including the diagnostic accuracy,limitations,and practical applicability of each *** will also briefly describe the potential role of elastography techniques in the evaluation of patients with NAFLD.

关键词： Nonalcoholic fatty liver disease Nonalcoholic steatohepatitis Liver steatosis Magnetic resonance spectroscopy Magnetic resonance imaging Ultrasonography Computed tomography Elastography

Notch1 and Notch4 are markers for poor prognosis of hepatocellular carcinoma

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Hepatobiliary & Pancreatic Diseases International 2013年第3期12卷 286-294页

作者： Soomin Ahn Jiyeon Hyeon cheol-Keun park Department of Pathology Samsung Medical Center Sungkyunkwan University School of Medicine

BACKGROUND: Notch signaling is critical to physiologic angiogenesis and has been implicated in tumor angiogenesis and metastasis. Notch signaling was reported to exert either oncogenic or tumor-suppressive function in hepatocellular carcinoma (HCC) tumorigenesis. However, the prognostic significance of Notch receptors in HCC remains uncertain. In this study, we investigated the roles of Notch receptors in the prognosis of HCC. METHODS: We investigated the expressions of Notch receptors in tumor tissue microarrays of 288 patients with primary HCC who had undergone curative resection using immunohistochemistry. Additionally, prognostic factors of HCC were examined by univariate and multivariate analyses. The median follow-up period was 97.1 months. Tumor recurrence was detected in 189 patients (65.6%), and 99 (34.4%) died of HCC. RESULTS: Cytoplasmic expression of Notch1, cytoplasmic expression of Notch3, coexistent nuclear expression of Notch3, and cytoplasmic Notch4 overexpression were observed in 145 (50.3%), 60 (20.8%), 17 (5.9%), and 172 (59.7%) of the 288 HCCs, respectively. Multivariate analyses revealed that Notch1 expression (P=0.029), Edmondson grade Ⅲ (P=0.038), and higher BCLC stage (P<0.001) were independent predictors of shorter disease-free survival. Cytoplasmic Notch3 expression tended to be an independent predictor of shorter disease-free survival (P=0.055). Notch1 expression (P=0.039), Notch4 overexpression (P=0.012), and higher BCLC stage (P<0.001) were independent predictors of shorter disease-specific survival. On univariate analysis, Notch1 expression tended to show an unfavorable influence on disease-specific survival (P=0.063) and Notch4 overexpression did not show an unfavorable influence on disease-specific survival (P=0.103). CONCLUSIONS: Notch1 expression might be an independent predictor of both shorter disease-free survival and shorter disease-specific survival in HCC patients after curative resection. Notch4 overexpression might be

关键词： Notch1 Notch4 hepatocellular carcinoma recurrence survival

Defect engineering of ternary Cu-In-Se quantum dots for boosting photoelectrochemical hydrogen generation

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Carbon Energy 2023年第12期5卷 215-228页

作者： Shi Li Sung-Mok Jung Wookjin Chung Joo-Won Seo Hwapyong Kim Soo Ik park Hyo cheol Lee Ji Su Han Seung Beom Ha In Young Kim Su-Il In Jae-Yup Kim Jiwoong Yang Department of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)DaeguRepublic of Korea Department of Chemical Engineering Dankook UniversityYonginRepublic of Korea Department of Chemistry and Nanoscience College of Natural ScienceEwha Womans UniversitySeoulRepublic of Korea Energy Science and Engineering Research Center Daegu Gyeongbuk Institute of Science and Technology(DGIST)DaeguRepublic of Korea

Heavy-metal-free ternary Cu–In–Se quantum dots(CISe QDs)are promising for solar fuel production because of their low toxicity,tunable band gap,and high light absorption *** defects significantly affect the photophysical properties of QDs,the influence on photoelectrochemical hydrogen production is not well ***,we present the defect engineering of CISe QDs for efficient solar-energy *** acid–base reactions between metal halide–oleylamine complexes and oleylammonium selenocarbamate are modulated to achieve CISe QDs with the controlled amount of Cu vacancies without changing their *** them,CISe QDs with In/Cu=1.55 show the most outstanding photoelectrochemical hydrogen generation with excellent photocurrent density of up to 10.7 mA cm-2(at 0.6 VRHE),attributed to the suitable electronic band structures and enhanced carrier concentrations/lifetimes of the *** proposed method,which can effectively control the defects in heavy-metal-free ternary QDs,offers a deeper understanding of the effects of the defects and provides a practical approach to enhance photoelectrochemical hydrogen generation.

关键词： copper-indium-selenide defect engineering photoelectrochemical hydrogen generation quantum dots solar hydrogen

Base pair distance analysis in single DNA molecule by direct stochastic optical reconstruction microscopy

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Chinese Chemical Letters 2015年第12期26卷 1490-1495页

作者： Suresh Kumar Chakkarapani Guenyoung park seong Ho Kang Department of Chemistry Graduate School Kyung Hee University Department of Applied Chemistry and Institute of Natural Sciences Kyung Hee University

Precise fluorescence imaging of single l-DNA molecules for base pair distance analysis requires a superresolution technique, as these distances are on the order of diffraction limit. Individual l-DNA molecules intercalated with the fluorescent dye YOYO-1 were investigated at subdiffraction spatial resolution by direct stochastic optical reconstruction microscopy（d STORM）. Various dye-to-DNA base pair ratios were imaged by photoswitching YOYO-1 between the fluorescent state and the dark state using two laser sources. The acquired images were reconstructed into a super-resolution image by applying Gaussian fitting to the centroid of the point spread function. By measuring the distances between localized fluorophores, the base pair distances in single DNA molecules for dye-to-DNA base pair ratios of 1：50,1：100, and 1：500 were calculated to be 17.1 0.8 nm, 34.3 2.2 nm, and 170.3 8.1 nm[17_TD$IF], respectively,which were in agreement with theoretical values. These results demonstrate that intercalating dye in a single DNA molecule can be photoswitched without the use of an activator fluorophore, and that super-localization precision at a spatial resolution of 17 nm was experimentally achieved.

关键词： stochastic DNA reconstructed fitting applying localization correction frames label localized

Use of a Digital Image Correlation Technique for Measuring the Material Properties of Beetle Wing

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Journal of Bionic Engineering 2009年第3期6卷 224-231页

作者： Tailie Jin Nam Seo Goo Sung-Choong Woo Hoon cheol park Biomemitics and Intelligent Microsystem Laboratory Department of Advanced Technology FusionKonkuk University

Beetle wings are very specialized flight organs consisting of the veins and *** it is necessary from a bionic view to investigate the material properties of a beetle wing *** the present study,we have used a Digital Image Correlation (DIC) technique to measure the elastic modulus of a beetle wing *** were prepared by carefully cutting a beetle hind wing into 3.0 mm by 7.0 mm segments (the gage length was 5 mm).We used a scanning electron microscope for a precise measurement of the thickness of the beetle wing *** specimen was attached to a designed fixture to induce a uniform displacement by means of a *** used an ARAMISTM system based on the digital image correlation technique to measure the corresponding displacement of a *** thickness of the beetle wing varied at different points of the *** elastic modulus differed in relation to the membrane arrangement showing a structural anisotropy;the elastic modulus in the chordwise direction is approximately 2.65 GPa,which is three times larger than the elastic modulus in the spanwise direction of 0.84 *** a result,the digital image correlation-based ARAMIS system was suc- cessfully used to measure the elastic modulus of a beetle *** addition to membrane's elastic modulus,we considered the Poisson's ratio of the membrane and measured the elastic modulus of a vein using an Instron universal tensile *** result reveals the Poisson's ratio is nearly zero and the elastic modulus of a vein is about 11 GPa.

关键词： digital image correlation technique beetle wing elastic modulus Poisson's ratio vein membrane