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Study of Partial Coefficients for Design of Semicircular Breakwaters

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China Ocean Engineering 2010年第1期24卷 29-40页

作者：郄禄文 Byung ho choi College of Civil Engineering Hebei University Department of Civil and Environmental Engineering Sungkyunkwan University300 Chunchun-dongJangan-GuSuwon

In the present study, the reliability design of semicircular breakwater is based on the verification of the rules defined by standard specifications, where partial coefficients are introduced to ensure safety. The reliability of the semicircular breakwaters has been analyzed by using the Hasofer-Lind method to determine the reliability index of structure that has correlated loads, utilizing the long-term observed wave data at a given place. The relation curve between reliability index and safety factor in the traditional design method, as well as the relationships between reliability index and partial coefficients, have been obtained. This paper proposes values of partial coefficients for the design expression of semicircular breakwaters in the cases of anti-sliding and anti-overturning.

关键词： partial coefftcient reliability index correlated variables semicircular breakwater

Shear deformable finite beam elements for composite box beams

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Acta Mechanica Sinica 2014年第2期30卷 223-240页

作者： Nam-Il Kim Dong-ho choi Department of Architectural Engineering Sejong University Department of Civil and Environmental Engineering Hanyang University

The shear deformable thin-walled composite beams with closed cross-sections have been developed for coupled flexural, torsional, and buckling analyses. A theoretical model applicable to the thin-walled laminated composite box beams is presented by taking into account all the structural couplings coming from the material anisotropy and the shear deformation effects. The current composite beam includes the transverse shear and the restrained warping induced shear deformation by using the first-order shear deformation beam theory. Seven governing equations are derived for the coupled axial-flexural-torsional-shearing buckling based on the principle of minimum total potential energy. Based on the present analytical model, three different types of finite composite beam elements, namely, linear, quadratic and cubic elements are developed to analyze the flexural, torsional, and buckling problems. In order to demonstrate the accuracy and superiority of the beam theory and the finite beam elements developed by this study,numerical solutions are presented and compared with the results obtained by other researchers and the detailed threedimensional analysis results using the shell elements of ABAQUS. Especially, the influences of the modulus ratio and the simplified assumptions in stress-strain relations on the deflection, twisting angle, and critical buckling loads of composite box beams are investigated.

关键词： Thin-walled Composite box beam Deflection Twisting angle Buckling load Shear deformation

Influence of the wastewater composition on denitrification and biological P-removal in the S-DN-P process: (c) Dissolved and undissolved substrates

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Journal of Environmental Sciences 2009年第8期21卷 1074-1079页

作者： Hee-Jeong choi Chul-ho choi Seung-Mok Lee Diwakar Tiwari Department of Environmental Engineering Kwandong University Department of Chemistry School of Physical Sciences Mizoram University

The denitdfication and P-removal in the sorption-denitrification-P-removal （S-DN-P） process were carded out under various wastewater compositions. It is noted that P-removal largely depends on the wastewater composition as well to the quantity of the substrates present in wastewater fraction. Three different wastewater fractions are obtained as： raw wastewater, dissolved wastewater （obtained with filtration using 0.45 μm filter）, and undissolved wastewater （i.e., infiltrate obtained by above filtration）. The ratio of P-release/CODtotal-consumption clearly inferred that undissolved wastewater possess very low value i.e., 0.0008 followed by raw wastewater 0.008 and dissolved wastewater 0.03. When this ratio was nearby 0.01, enhanced P-removal was observed. Moreover, the ratio of P-uptake to NO3^--N decomposition for raw wastewater was two times for dissolved wastewater. Interestingly, it was observed that the P-removal and denitrification depend not only on the dissolved substrates but also the undissolved substrates present in the wastewater. The result of the P-removal obtained with this S-DN-P process did not show a big difference of 36%, 34% and 30%, respectively, for raw, dissolved and undissolved wastewater.

关键词： denitrification polyhydroxybutyrate sequencing batch biofilm reactor sorption denitrification P-removals

Aerosol-assisted rapid synthesis of SnS-C composite microspheres as anode material for Na-ion batteries

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Nano Research 2015年第5期8卷 1595-1603页

作者： Seung ho choi Yun Chan Kang Department of Materials Science and Engineering Korea University Anam-Dong Seongbuk-Gu Seou1136-713 Republic of Korea

SnS-C composite powders were prepared through one-pot spray pyrolysis for use as anode materials for Na-ion batteries. C microspheres with uniformly attached cubic-like SnS nanocrystals, which have an amorphous C coating layer, were formed at a preparation temperature of 900 ℃. The initial discharge capacities of the bare SnS and SnS-C composite powders at a current density of 500 mA·g^-1 were 695 and 740 mA·h·g^-1, respectively. The discharge capacities after 50 cycles and the capacity retentions measured from the second cycle of the bare SnS and SnS-C composite powders were 25 and 433 mA.h.g-1 and 5 and 89%, respectively. The prepared SnS-C composite powders with high reversible capacities and good cycle performance can be used as Na-ion battery anode materials.

关键词： tin sulfide anode material carbon composite sodium battery energy storage

ON THE ASYMPTOTIC DYNAMICS OF THE VLASOV-YUKAWA-BOLTZMANN SYSTEM NEAR VACUUM

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Acta Mathematica Scientia 2015年第4期35卷 887-905页

作者： Sun-ho choi Seung-Yeal HA Department of Mathematical Sciences KAIST Department of Mathematical Sciences and Research Institute of Mathematics Seoul National University

In this pape,~ we study uniform L1-stability and asymptotic completeness of the Vlasov-Yukawa-Boltzmann （V-Y-B） system. For a sufficiently small rand smooth initial data, we show that classical solutions exist globally and satisfy dispersion estimates, uniform L1-stability with respect to initial data and scattering type estimate. We show that the short range nature of interactions due to the Yukawa potential enables us to construct robust Lyapunov type functional to derive scattering states. In the zero mass limit of force carrier particles, we also show that the classical solutions to the V-Y-B system converge to that of the Vlasov-Poisson-Boltzmann （V-P-B） system in any finite time interval

关键词： asymptotic completeness collision operator the Vlasov-Yukawa-Boltzmannsystem uniform L1-stability

Enhanced Li^＋ storage properties of few-layered MoS2-C composite microspheres embedded with Si nanopowder

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Nano Research 2015年第8期8卷 2492-2502页

作者： Seung ho choi Yun Chan Kang Department of Materials Science and Engineering Korea University Anam-Dong Seongbuk-Gu Seoul 136-713 Republic of Korea

A few-layered MoS2-C composite material is studied as a supporting material for silicon nanopowder. Microspheres of the few-layered MoS2-C composite embedded with 30 wt.% Si nanopowder are prepared by one-pot spray pyrolysis. The Si nanopowder particles with high capacity are completely surrounded by the few-layered MoS2-C composite matrix. The discharge capacities of the MoS2-C composite microspheres with and without 30 wt.% Si nanopowder after 100 cycles are 1,020 and 718 mAh·g^-1 at a current density of 1,000 mA·g^-1 respectively. The spherical morphology of the MoS2-C composite microspheres embedded with Si nanopowder is preserved even after 100 cycles because of their high structural stability during cycling. The MoS2-C composite layer prevents the formation of unstable solid-electrolyte interface （SEI） layers on the Si nanopowder. Furthermore, as the MoS2-C composite matrix exhibits high capacity and excellent cycling performance, these characteristics are also reflected in the MoS2-C composite microspheres embedded with 30 wt.% Si nanopowder.

关键词： molybdenum sulfide silicon anode material lithium batteries spray pyrolysis

Possibility of Solid Hydrometeor Growth Zone Identification Using Radar Spectrum Width

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Advances in Atmospheric Sciences 2023年第2期40卷 317-332页

作者： Sung-ho SUH Eun-ho choi hong-Il KIM Woonseon JUNG Flight Safety Technology Division NARO Space CenterKorea Aerospace Research Institute(KARI)508 Haban-roBongrae-myeonGoheung-gunJeollanam-do 59571Republic of Korea Research Applications Department National Institute of Meteorological Sciences33Seohobuk-roSeoqwipo-siJeju-do 63568Republic of Korea

In this study,the correlation between simulated and measured radar velocity spectrum width(σ_(v))is *** results show that the dendrites growth zones(DGZs)and needles growth zones(NGZs)mostly contain dendrites(DN)and needles(NE),***σ_(v) zones(1.11.2 m s^(-1),a differential reflectivity(ZDR)higher than 0 dB,and a cross-correlation coefficient(ρhv)less than *** contrast,prolate particles with relatively uniform shapes were observed in the NGZ withσ_(v)how that the DN exhibited a largerσ_(v) compared to the NE,and this observedσ_(v) was strongly dependent on the wind fluctuations(v’)due to turbulence or wind *** contrast,the NE exhibited a significantly smallσ_(v)~0.55 m s^(-1),which converges irrespective of v’.In addition,a strong correlation between the measuredσ_(v) values at five radar elevation angles(θ=6.2°,9.1°,13.1°,19°,and 80°)and those simulated in this study confirmed the significance of the analysis results.

关键词： spectrum width weather radar aerodynamic properties dendritic growth zone hydrometeor classifications

Experience of limited pancreatic head resection for management of branch duct intraductal papillary mucinous neoplasm in a single center

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World Journal of Gastroenterology 2009年第23期15卷 2904-2907页

作者： Kwang Yeol Paik Seong ho choi Department of Surgery Kepco Medical Foundation Hanil General Hospital #388-1 Ssangmoon-Dong Dobong-Gu Seoul 132-033 South Korea Department of Surgery Samsung Medical Center College of Medicine Sungkyunkwan University #50 Irwon-Dong Gangnam-Gu Seoul 135-710 South Korea

AIM: To share our surgical experience and the outcome of limited pancreatic head resection for the management of branch duct intraductal papillary mucinous neoplasm (IPMN). METhoDS: Between May 2005 and February 2008, nine limited pancreatic head resections (LPHR) were performed for IPMN of the pancreatic head. We reviewed the nine patients, retrospectively. RESULTS: Tumor was located in the uncinate process of the pancreas in all nine patients. Three patients had stents inserted in the main pancreatic duct due to injury. The mean size of tumor was 28.4 mm. Postoperative complications were found in f ive patients: 3 pancreatic leakages, a pancreatitis, and a duodenal stricture. Pancreatic leakages were improved by external drainage. No perioperative mortality was observed and all patients are recorded alive during the mean follow-up period of 17.2 mo. CONCLUSION: In selected patients after careful evaluation, LPHR can be used for the treatment of branch duct type IPMN. In order to avoid pancreatic ductal injury, preand intra-operative defi nite localization and careful operative techniques are required.

关键词： Limited pancreatic head resection Branchduct type Intraductal papillary mucinous neoplasm

Blood flow Interpretation in Femoral Pseudoaneurysm

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Journal of Thermal Science 2013年第3期22卷 229-233页

作者： Sang-ho Suh Young ho choi Hyoung-ho Kim Min-Gyu Jeon Deog-Hee Doh Dept. of Mechanical Engineering Soongsil University Department of Radiology Seoul Nat'l University Boramae Hospital Graduate School Korea Maritime Univ. Division of Mechanical and Energy Systems Engineering Korea Maritime University

A femoral artery pseudoaneurysm is one complication of vascular intervention, and the incidence is increasing. Early management is then needed to avoid potential dangers from it. It differs from a true aneurysm in that it doesn't include any component of the vascular wall, and is not studied as much as a true aneurysm. Here, a model of a femoral pseudoaneurysm was made and a Computational Fluid Dynamics(CFD) simulation was verified with PIV experiment. Afterwards, a CFD simulation with two different models was performed to look for any findings which may help in developing new treatment methods.

关键词： Femoral Artery, Pseudoaneurysm, Numerical and PIV experimental Interpretation