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Morphology Control of Bi2S3 Nanostructures and the Formation Mechanism

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Chinese Journal of Chemistry 2013年第6期31卷 752-756页

作者： HeeJin kim Ji-eun Park kyung kim Mi-kyung Han Sung-Jin kim Wooyoung Lee Department of Materials Science and Engineering Yonsei University Seou1120- 749 Korea Department of Chemistry and Nano Science Ewha Womans University Seoul 120-750 Korea

Bismuthinite （Bi2S3）nanostructures were prepared by a hydrothermal method with sodium ethylenediamine- tetraacetate （EDTA-Na2）. The morphology of Bi2S3 nanostructures was changed from a nanorod to a nanoplate by presence of the EDTA-Na2. The altered morphology was caused by the capping effect of EDTA-Na2 with Bi3＋ ions, which induces the suboptimal growth direction due to partially blocking the preferential orientation direction. When the EDTA-Na2/Bi3＋ molar ratio= 1, the growth of Bi2S3 nanostructures was not allowed due to the chelating effect of EDTA-Na2. The obtained Bi2S3 nanorods, stacked nanorods, nanoplates and nanoparticles were characterized using X-ray diffraction （XRD）, transmission electron microscopy （TEM）, high-resolution transmission electron mi- croscopy （HRTEM） and selected area electron diffraction （SAED） pattern. A possible formation mechanism of these morphologies was proposed. The successful synthesis of various morphologies of nanostructured Bi2S3 may open up new possibilities for thermoelectric, electronic and optoelectronic uses of nanodevices based on Bi2S3 nanostructure.

关键词： bismuth sulfide (Bi2S3) hydrothermal nanorod nanoplate thermoelectric material

The validity of the Reynolds equation in spool valve analysis considering cavitation

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Friction 2016年第3期4卷 266-276页

作者： Sung-Ho HONG kyung-Woong kim School of Mechanical Aerospace & Systems Engineering Korea Advanced Institute of Science and Technology 291 Daehak-ro Yuseong-guDaejeon 305-701 Republic of Korea

The purpose of this research is to investigate the validity of the Reynolds equation in spool valve analysis under cavitation. This study is carried out for a laminar and isothermal flow between a sleeve and spool with grooves. The pressure and lateral force obtained from the Reynolds equation and the Navier-Stokes equation are compared with variations of aspect ratio, cross sectional area, and number of grooves. The cavitation phenomenon is considered by using a cavitation model in the Navier-Stokes equation and the Reynolds cavitation boundary condition in the Reynolds equation. A large difference of more than 20% is found between the equations for a lateral force of spool valve with many grooves. It was found that the Reynolds equation is not suitable for calculation of a lateral force of the spool valve with multiple-grooves of which the width and depth are even larger than the clearance under cavitation.

关键词： validity Reynolds equation Navier-Stokes equation spool valve cavitation

CO_2 exchange at air-sea interface in the Huanghai Sea

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Acta Oceanologica Sinica 2000年第1期19卷 79-89页

作者： Dong-Chan oh Mi-kyung Park kyung-Ryul kim (1. Department of Oceanography, Seoul National University, Seoul 151-742, Korea) Department of Oceanography Seoul National University Seoul 151-742 South Korea

During the Huanghai Sea Circulation and Material Flux Expedition in Spring 1996, fco_2 in surface water and atmosphere was measured. The fco2 in surface water varied in a range from 220 to 360 uatm1) while atmospheric concentration was nearly constant at 360μatm, showing that the Huanghai Sea surface waters were undersaturated with respect to atmospheric Co during the time of investigation. A model was developed in this study in order to estimate the Co flux at the air-sea interface. The model incorporates the time-series variations of the distributions in SST (sea surface temperature), salinity, mixed-layer depth, atmospheric fco2, gas-transfer velocity, and CZCS chlorophyll concentration in the Huanghai Sea and was calibrated with the observed fco2 data. The primary parameter affecting fco2 in surface water is the variation of SST through time. The annual fluxes of Co are estimated as 0. 033 Gt C from the sea into the atmosphere and 0. 044 Gt C from the air into sea. The Huanghai Sea, thus behaves as a CO2 sink absorbing 0. 011 Gi C of CO2 a year. *** to about 0. 5 % of global oceanic absorption capacity.

关键词： Huanghai Sea CO2 exchange air-sea interface

Recurrence after endoscopic piecemeal mucosal resection for large sessile colorectal polyps

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World Journal of Gastroenterology 2010年第22期16卷 2806-2811页

作者： Guh Jung Seo Dae kyung Sohn kyung Su Han Chang Won Hong Byung Chang kim Ji Won Park Hyo Seong Choi Hee Jin Chang Jae Hwan oh Center for Colorectal Cancer Research Institute and Hospital National Cancer Center

AIM: To evaluate the safety and outcomes of endoscopic piecemeal mucosal resection (EPMR) for large sessile colorectal polyps. METHODS: The patients enrolled in this study were 47 patients with 50 large sessile polyps (diameter, 2 cm or greater) who underwent EPMR using a submucosal saline injection technique between December 2002 and October 2005. All medical records, including characteristics of the patients and polyps, complications, and recurrences, were retrospectively reviewed. The first follow-up endoscopic examination was performed at 3-6 mo after initial endoscopic resection, and the second at 12 mo postEPMR. Subsequent surveillance colonoscopic examinations were individualized, taking risk factors into account. RESULTS: The patients were 23 men and 24 women,with a mean age of 60 years. Mean polyp size was 30.1 mm. Of 50 polyps identified, 34 (68%) were benign and 16 (32%) were malignant. There were 6 (12%) cases with EPMR-related bleeding: 5 intra-procedural and 1 early post-procedural bleeding. All bleeding episodes were managed by endoscopic clipping or argon beam coagulation. There were no perforations. Recurrence was identified in 5 cases (12.2%): 4 local recurrences detected at 3 mo post-EPMR and 1 local recurrence detected at 14 mo post-EPMR. The recurrence rate after EPMR was 3.1% for benign polyps and 33.3% for malignant polyps (P < 0.05). Median follow-up time was 37 mo. CONCLUSION: EPMR is safe, but should be applied carefully in malignant polyps. Close follow-up endoscopic examinations are necessary for early detection of recurrence.

关键词： Colonoscopy Colorectal neoplasm Endoscopic piecemeal mucosal resection Large sessile polyps

Canonical Foliations of Certain Classes of Almost Contact Metric Structures

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Acta Mathematica Sinica,English Series 2005年第4期21卷 841-846页

作者： Tae Wan kim Hong kyung PAK Department of Mathematics Education Silla UniversityPusan617-736.Korea Department of Computer and Information Security Daegu Haany University

The purpose of this paper is to study the canonical foliations of an almost cosymplectic or almost Kenmotsu manifold M in a unified way. We prove that the canonical foliation F defined by the contact distribution is Riemannian and tangentially almost Kahler of codimension 1 and that F is tangentially Kahler if the manifold M is normal. Furthermore, we show that a semi-invariant submanifold N of such a manifold M admits a canonical foliation FN which is defined by the antiinvariant distribution and a canonical cohomology class c（N） generated by a transversal volume form for FN. In addition, we investigate the conditions when the even-dimensional cohomology classes of N are non-trivial. Finally, we compute the Godbillon Vey class for FN.

关键词： Almost α-cosymplectic manifold Almost cosymplectic manifold Almost Kenmotsu manifold Semi-invariant submanifold

Determination of diffusion coefficient by image-based fluorescence recovery after photobleaching and single particle tracking system implemented in a single platform

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Journal of Innovative Optical Health Sciences 2021年第2期4卷 93-101页

作者： Donghee Lee Jeonghoon Lee Jung kyung kim Department of Genetics Cell Biology and Anatomy University of Nebraska Medical CenterOmahaNE 68198USA School of Mechanical Engineering KOREA TECH Cheonan 31253Republic of Korea School of Mechanical Engineering and Department of Integrative Biomedical Science and Engineering Graduate School Kookmin University Seoul 02707Republic of Korea

Fluorescence recovery after photobleaching(FRAP)and single particle tracking(SPT)techni-ques determine the diffusion coefficient from average diffusive motion of high-concentration molecules and from trajectories of low-concentration single molecules,*** dif-fusion coefficients measured by FRAP and SPT techniques for the same biomolecule on cell membrane have exhibited inconsistent values across laboratories and platforms with larger dif-fusion coefficient determined by FRAP,but the sources of the inconsistency have not been investigated ***,we designed an image-based FRAP-SPT system and made a direct comparison between FRAP and SPT for diffusion coefficient of submicron particles with known theoretical values derived from Stokes-Einstein equation in aqueous *** combined iFRAP-SPT technique allowed us to measure the diffusion coefficient of the same fluorescent particle by utilizing both techniques in a single platform and to scrutinize inherent errors and artifacts of *** results reveal that diffusion coefficient overestimated by FRAP is caused by inaccurate estimation of the bleaching spot size and can be corrected by simple image *** iFRAP-SPT technique can be potentially used for not only cellular membrane dynamics but also for quantitative analysis of the spatiotemporal distribution of the solutes in small scale analytical devices.

关键词： Diffusion coefficient fluorescence recovery after photobleaching(FRAP) single particle tracking(SPT)

Effects of coarse riblets on air flow structures over a slender delta wing using particle image velocimetry

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Chinese Journal of Aeronautics 2019年第6期32卷 1367-1379页

作者： Mahdi NILI-AHMADABADI Omid NEMATOLLAHI kyung Chun kim Department of Mechanical Engineering Isfahan University of TechnologyIsfahan 84156-83111Iran School of Mechanical Engineering Pusan National UniversityBusan 609-735Republic of Korea

This research investigates the aerodynamic performance and flow characteristics of a delta wing with 65° sweep angle and with coarse axial riblets,and then compares with that of a smooth-surface delta *** Image Velocimetry(PIV)were utilized to visualize the flow over the wing at 6 cross-sections upright to the wing surface and parallel to the wing span,as well as 3 longitudinal sections on the leading edge,symmetry plane,and a plane between them at Angles of Attack(AOA)=20°and 30°and Re=1.2×10~5,2.4×10~5,and 3.6×10~*** effects of the riblets were studied on the vortices diameter,vortex breakdown location,vortices distance from the wing surface,flow lines pattern nearby the wing,circulation distribution,and *** results show that the textured model has a positive effect on some of the parameters related to drag reduction and lift *** riblets increase the flow momentum near the wing’s upper surface except near the *** also increase the flow momentum behind the wing.

关键词： Aerodynamic performance Coarse riblet Delta wing Flow structures Particle image velocimetry Vortex

Anti-inflammatory and anti-apoptotic effects of rosuvastatin by regulation of oxidative stress in a dextran sulfate sodium-induced colitis model

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World Journal of Gastroenterology 2017年第25期23卷 4559-4568页

作者： Seung Kak Shin Jae Hee Cho Eui Joo kim Eun-kyung kim Dong Kyun Park Kwang An Kwon Jun-Won Chung Kyoung oh kim Yoon Jae kim Division of Gastroenterology and Hepatology Department of Internal Medicine Gachon University Gil Medical Center

AIM To evaluate the anti-inflammatory and anti-apoptotic effects of rosuvastatin by regulation of oxidative stress in a dextran sulfate sodium(DSS)-induced colitis *** An acute colitis mouse model was induced by oral administration of 5% DSS in the drinking water for 7 d. In the treated group, rosuvastatin(0.3 mg/kg per day) was administered orally before and after DSS administration for 21 d. On day 21, mice were sacrificed and the colons were removed for macroscopic examination, histology, and Western blot analysis. In the in vitro study, IEC-6 cells were stimulated with50 ng/m L tumor necrosis factor(TNF)-α and then treated with or without rosuvastatin(2 μmol/L). The levels of reactive oxygen species(ROS), inflammatory mediators, and apoptotic markers were measured. RESULTS In DSS-induced colitis mice, rosuvastatin treatment significantly reduced the disease activity index and histological damage score compared to untreated mice(P < 0.05). Rosuvastatin also attenuated the DSSinduced increase of 8-hydroxy-2'-deoxyguanosine and NADPH oxidase-1 expression in colon tissue. Multiplex ELISA analysis revealed that rosuvastatin treatment reduced the DSS-induced increase of serum IL-2, IL-4, IL-5, IL-6, IL-12 and IL-17, and G-CSF levels. The increased levels of cleaved caspase-3, caspase-7, and poly(ADP-ribose) polymerase in the DSS group were attenuated by rosuvastatin treatment. In vitro, rosuvastatin significantly reduced the production of ROS, inflammatory mediators and apoptotic markers in TNF-α-treated IEC-6 cells(P < 0.05).CONCLUSION Rosuvastatin had the antioxidant, anti-inflammatory and anti-apoptotic effects in DSS-induced colitis model. Therefore, it might be a candidate anti-inflammatory drug in patients with inflammatory bowel disease.

关键词：氧化应力煽动性的肠疾病 Rosuvastatin Apoptosis

Efective Object Identification and Association by Varying Coverage Through RFID Power Control

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Journal of Computer Science & Technology 2014年第1期29卷 4-20页

作者： Shung Han Cho kyung Hoon kim Sangjin Hong IEEE System LSI Business Samsung Electronics Department of Electrical and Computer Engineering Stony Brook University

This paper presents an effective power scheduling strategy for energy efficient multiple objects identification and association. The proposed method can be utilized in many heterogeneous surveillance systems with visual sensors and RFID （radio-frequency identification） readers where energy efficiency as well as association rate are critical Multiple objects positions and trajectory estimates are used to decide the power level of RFID readers. Several key parameters including the time windows and the distance separations are defined in the method in order to minimize the effects of RFID coverage uncertainty. The power cost model is defined and incorporated into the method to minimize energy consumption and to maximize association performance. The proposed method computes the power cost using the range of the outermost position for possible single association and group associations at every sampling time. An RFID reader is activated with the proper coverage range when the power cost for the current time is lower than the power cost for the next time sample. The simplicity of the power cost model relieves the problematic combinatorial comparisons in multiple object cases. The performance comparison simulation with the minimum and maximum energy consumption shows that the proposed method achieves fast single associations with less energy consumption. Finally, the realistic comparison simulation with the fixed range RFID readers demonstrates that the proposed method outperforms the fixed ranges in terms of single association rate and energy consumption.

关键词： object association RFID power control power scheduling visual sensor collaboration