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Geometrical and Geotechnical Characteristics of Landslides in Korea under Various Geological Conditions

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Journal of Mountain Science 2015年第5期12卷 1267-1280页

作者： Kyeong-Su KIM Young-suk song Geologic Environment Division Korea Institute of Geoscience and Mineral Resources

The goal of this study is to determine the geometrical and geotechnical characteristics of landslides under various geological conditions using detailed field surveys, laboratory soil tests and precipitation records. Three study areas are selected to consider different rocks, including gneiss in Jangheung, granite in Sangju and sedimentary rocks in Pohang, South Korea. Many landslides have occurred in these three areas during the rainy *** records indicate that landslides occurring in the gneiss area of Jangheung and granite area of Sangju may be influenced by the hourly rainfall intensity rather than cumulative ***, landslides occurring in the sedimentary rock area of Pohang may be influenced by hourly rainfall intensity and cumulative rainfall. To investigate the factors that influence these types of landslides, a detailed landslide survey was performed and a series of laboratory soil tests were *** to the detailed field survey, most landslides occurred on the flanks of mountain slopes, and the slope inclination where they occurred mostly ranged from 26 to 30 degrees, regardless of the geological conditions. The landslide in the gneiss area of Jangheung is larger than the landslides in the granite area of Sangju and sedimentary rock area of ***, the landslide in the sedimentary rock area is shorter and shallower than the landslides in the gneiss and granite areas. Thus, the shape and size of the landslide are clearly related to the geological conditions. According to the integrated soil property and landslide occurrence analyses results, the average dry unit weight of the soils from the landslide sites is smaller than that of the soils obtained from the nonlandslide site. The average coefficient of permeability of soils obtained from the landslide sites is greater than that of soils obtained from the non-landslide sites with the same geology. These results indicate that the soils from the landslide site

关键词： Landslides Geological condition Geometrical characteristics Precipitation Soilproperties South Korea

Effect of Fe_2P in LiFePO_4/Fe_2P composite on electrochemical properties synthesized by MA and control of heat condition

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Rare Metals 2006年第z2期25卷 179-183页

作者： PARK jong suk LEE Kyung Tae LEE Kyung Sub Department of Material Science and Engineering Hanyang University Seoul 133-731 Korea

In order to control the size and distribution of the high conductive Fe2P in LiFePO4/Fe2P composite, two different cooling rates (Fast: 15 ℃·min-1, Slow: 2 ℃·min-1) were employed after mechanical alloying. The discharge capacity of the fast cooled was 83 mAh·g-1 and the slow cooled 121 mAh·g-1. The particle size of the synthesized powder was examined by transmission electron microscopy and distribution of Fe2P was characterized using scanning electron microscopy (SEM). In addition, two-step heat treatment was carried out for better distribution of Fe2P. X-ray diffraction (XRD) and Rietveld refinement reveal that LiFePO4/Fe2P composite consists of 95.77% LiFePO4 and 4.33% of Fe2P.

关键词： LiFePO4/Fe2P composite mechanical alloying heat treatment discharge capacity

Grade-4 commercially pure titanium with ultrahigh strength achieved by twinning-induced grain refinement through cryogenic deformation

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Journal of Materials Science & Technology 2021年第7期66卷 193-201页

作者： Seong-Woo Choi Jae sukjeong jong Woo Won Jae Keun Hong Yoon suk Choi Titanium Department.Korea Institute of Materials Science Changwon51508Republic of Korea School of Materials Science and Engineering Pusan National UniversityPusan.46241Republic of Korea Materials and Manufacturing Development Team Doosan Heavy Industries and ConstructionChangwon51711Republic of Korea

The yield strength of commercially pure(CP) Ti of ASTM grade 4, the strongest among all the CP-Ti grades, is too low for structural applications that require high-strength materials. Here, we demonstrate the strengthening of grade-4 CP Ti by cryogenic-temperature rolling(CTR), which enables deformation twinning in grade-4 CP Ti to achieve twinning-induced grain refinement. CTR activated {11.22} twinning and {10.12} twinning, which are the most common twinning systems in pure Ti, whereas room-temperature rolling(RTR) did not activate any twinning system. CTR with imposing an area reduction of just 30% significantly increased the yield strength of the CP Ti to 946 MPa, which is not achievable through typical processes performed at or above room temperature and is comparable to that of commercial Ti-6 Al-4 V. The significant increase in strength was due to microstructural strengthening caused by twinning-induced grain refinement, combined with dislocation accumulation. In contrast to RTR, CTR greatly increased the stress concentration at grain boundaries(GBs), which caused the unusual activation of twinning in the grade-4 CP Ti by facilitating twin nucleation at GBs. The stress concentration increased because CTR activated the slip to a lesser extent compared to RTR, thereby reducing the strain compatibility between neighboring grains. These results will contribute to development of ultrahigh-strength CP Ti and may thereby extend its use to structural applications that require high-strength materials.

关键词： Titanium Twinning Cryogenic deformation Grain refinement Tensile properties

High-efficiency single and tandem fullerene solar cells with asymmetric monofluorinated diketopyrrolopyrrole-based polymer

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Journal of Energy Chemistry 2022年第1期31卷 236-245,I0007页

作者： Shafket Rasool Quoc Viet Hoang Doan Van Vu Chang Eun song Hang Ken Lee Sang Kyu Lee jong-Cheol Lee Sang-Jin Moon Won suk Shin Institute of Chemical Technology(KRICT) 141 Gajeong-roYuseongDaejeon 34114Republic of Korea Advanced Materials and Chemical Engineering University of Science and Technology(UST)217 CajeongroYuseongDaejeon 34113Republic of Korea Vietnam Standards and Quality Institute(VSQI) Directorate for StandardsMetrology and Quality(STAMEQ)No.8.Hoang Quoc VietCau GiayHanoiViet Nam

Design and synthesis of low bandgap(LBG) polymer donors is inevitably challenging and their processability from a non-halogenated solvent system remains a hurdle to overcome in the area of highperformance polymer solar cells(PSCs).Due to a high aggregation tendency of LBG polymers,especially diketopyrrolopyrrole(DPP)-based polymers coupled with bithiophenes in the polymer backbones,their widespread adoption in non-ha logena ted solvent-processed PSCs has been ***,a novel LBG DPP-based polymer,called PDPP4 T-1 F with asymmetric arrangement of fluorine atom,has been successfully synthesized and showed an outstanding power conversion efficiency(PCE) of 10.10% in a singlejunction fullerene-based ***,an impressive PCE of 13.21% has been achieved in a tandem device from a fully non-halogenated solvent system,which integrates a wide bandgap PDTBTBz-2 F polymer in the bottom cell and LBG PDPP4 T-1 F polymer in the top *** achieved efficiency is the highest value reported in the literature to date in fullerene-based tandem *** found that a uniformly distributed interpenetrating fibril network with nano-scale phase separation and anisotropy of the polymer backbone orientation for efficient charge transfer/transport and suppressed charge recombination in PDPP4 T-1 F-based PSCs led to outstanding PCEs in single and tandem-junction PSCs.

关键词： Low bandgap polymers Diketopyrrolopyrrole Tandem polymer solar cells Non-halogenated solvent Monofluoro-bithiophene

Antibacterial Behaviour of Quaternized Poly(vinyl chloride)-g-Poly(4-vinyl pyridine) Graft Copolymers

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Chinese Journal of Polymer Science 2015年第2期33卷 265-274页

作者： Madhumita Patel Rajkumar Patel Won Seok Chi jong Hak Kim Jung-suk Sung Department of Life Science Dongguk University-Seoul 3-26 Phil-dong Chung-gu Seoul 100-715 South Korea Department of Chemistry and Nano Science Ewha Womans University Global Top 5 Research Program52 Ewhayeodae-gil Seodaemun-gu Seoul 120-750 Korea Department of Chemical and Biomolecular Engineering Yonsei University 262 SeongsannoSeodaemun-gu Seoul 120-749 South Korea

Amphiphilic graft copolymers consisting of poly（vinyl chloride）（PVC） main chains and poly（4-vinyl pyridine）（P4VP） side chains were synthesized via atom transfer radical polymerization（ATRP） using direct initiation of chlorine atoms. The successful synthesis of PVC-g-P4 VP graft copolymers was confirmed by Fourier transform infrared spectroscopy（FTIR） and proton nuclear magnetic resonance（1H-NMR）. Transmission electron microscope（TEM） and small angle X-ray scattering（SAXS） analysis showed that PVC-g-P4 VP exhibited microphase-separated, ordered structure with 37.6 nm of domain spacing, which was not observed in neat PVC. For antibacterial applications, the tertiary nitrogen atoms of PVC-gP4 VP was quaternized using 1-bromohexane, as confirmed by FTIR measurements. Bacteria including Escherichia coli（E. coli）, Staphylococcus aureus（S. aureus）, Bacillus cereus（B. cereus）, and Pseudomonas aeruginosa（P. aeruginosa） were completely killed in 24 h on the quaternized PVC-g-P4VP（46% grafting） surface, indicating its excellent antibacterial behavior while it showed to be cytotoxic to mammalian cell.

关键词： Graft copolymer Membranes Atom transfer radical polymerization Antibacterial property Quaternized polymer

Variability and Risk Analysis of Hong Kong Air Quality Based on Monsoon and El Nino Conditions

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Advances in Atmospheric Sciences 2013年第2期30卷 280-290页

作者： jong-suk KIM ZHOU Wen Ho Nam CHEUNG Chak Hang CHOW School of Energy and Environment City University of Hong Kong Hong Kong Guy Carpenter Asia-Pacific Climate Impact Centre City University of Hong Kong Hong Kong

This study presents an exploratory analysis aimed at improving understanding of the variability of Hong Kong air quality associated with different climate conditions. Significantly negative correlations were found when Nifio 3 led particulate matter 〈10 p.m PM10） and NO2 by 2 3 months over the Hong Kong territory, while the other pollutants （e.g., Oa, SO2） showed modest correlations. A significant decreasing trend in visibility was observed during the autumn and winter, which has potential implications for the air-quality degradation and the endangerment of human health in Hong Kong. In an E1 Nifio summer, the visibility was relatively better, while visibility in other seasons was diminished. On the other hand, in La Nifia events, significant changes occurred in visibility in winter and autumn. Air pollution indices were less sensitive to the South China Summer Monsoon （SCSM）, but a relatively high correlation existed between the East Asian Winter Monsoon （EAWM） and air pollutants. Rainfall was lower during most of the strong EAWM years compared to the weak years. This result suggests that the pollutants that accumulate in Hong Kong are not easy to wash out, so concentrations remain at a higher level. Finally, based on the conditional Air Pollution Index （API） risk assessment, site-specific vulnerabilities were analyzed to facilitate the development of the air-quality warning systems in Hong Kong.

关键词： air quality E1 Nifio/La Nifia Monsoon API risk Hong Kong

Hepatic arterial infusion chemotherapy in hepatocellular carcinoma with portal vein tumor thrombosis

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World Journal of Gastroenterology 2013年第29期19卷 4679-4688页

作者： Do Seon song Si Hyun Bae Myeong Jun song Sung Won Lee Hee Yeon Kim Young Joon Lee Jung suk Oh Ho jong Chun Hae Giu Lee jong Young Choi Seung Kew Yoon Department of Internal Medicine College of Medicine The Catholic University of Korea Seoul 137-040 South Korea Department of Radiology College of Medicine The Catholic University of Korea Seoul 137-040 South Korea

AIM: To evaluate the prognostic factors and efficacy of hepatic arterial infusion chemotherapy in hepatocellular carcinoma with portal vein tumor thrombosis. METHODS: Fifty hepatocellular carcinoma (HCC) patients with portal vein tumor thrombosis (PVTT) were treated using hepatic arterial infusion chemotherapy (HAIC) via a subcutaneously implanted port. The epirubicin-cisplatin-5-fluorouracil (ECF) chemotherapeutic regimen consisted of 35 mg/m 2 epirubicin on day 1, 60 mg/m 2 cisplatin for 2 h on day 2, and 500 mg/m 2 5-fluorouracil for 5 h on days 1-3. The treatments were repeated every 3 or 4 wk. RESULTS: Three (6%) of the 50 patients achieved a complete response (CR), 13 (26%) showed partial responses (PR), and 22 (44%) had stable disease (SD).The median survival and time to progression were 7 and 2 mo, respectively. After 2 cycles of HAIC, CR was achieved in 1 patient (2%), PR in 10 patients (20%) and SD in 26 patients (52%). Significant pre-treatment prognostic factors were a tumor volume of < 400 cm 3 (P = 0.01) and normal levels of protein induced by vitamin K absence or antagonist (PIVKA)-Ⅱ (P = 0.022). After 2 cycles of treatment, disease control (CR + PR + SD) (P = 0.001), PVTT response (P = 0.003) and α-fetoprotein reduction of over 50% (P = 0.02) were independent factors for survival. Objective response (CR + PR), disease control, PVTT response, and combination therapy during the HAIC were also significant prognostic factors. Adverse events were tolerable and successfully managed. CONCLUSION: HAIC may be an effective treatment modality for advanced HCC with PVTT in patients with tumors < 400 cm 3 and good prognostic factors.

关键词： Hepatocellular carcinoma Hepatic arterial infusion chemotherapy Portal vein tumor thrombosis

Selectively patterned TiO2 nanorods as electron transport pathway for high performance perovskite solar cells

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Nano Research 2019年第3期12卷 601-606页

作者： Daihong Huh Kyoungsuk Oh Minjin Kim Hak-jong Choi Dong suk Kim Heon Lee Department of Materials Science and Engineering Korea University Anam-ro 145 Sungbuk-Gu Seoul 136-701 Republic cf Korea KIER-UNIST Advanced Center for Energy Korea Institute of Energy Research (KIER) UNIST-Gil 50 Eonyang-eup Ulju-gun Ulsan 689-851 Republic of Korea Department of Electrical and Systems Engineering University of Pennsylvania Philadelphia Pennsylvania 19104 USA

Organic-inorganic hybrid perovskite solar cells (PSCs) are attracting tremendous attention for new-generation photovoltaic devices because of their excellent power conversion efficiency and simple fabrication process. One of the various approaches to increase the efficiency of PSCs is to change the material or structure of the carrier transport layer. Here, optically long and electrically short structural concept is proposed to enhance the characteristics of a PSC by employing selectively grown single crystalline TiO2 nanorods. The approach has the merit of increasing the electro n-hole separati on effectively and en ables a thicker active layer to be coated without electrical loss by using TiO2 nano rods as an electr on pathway. Moreover, selectively grow n TiO2 nano rods in crease the optical path of the in cide nt light via scatteri ng effects and en able a smooth coati ng of the active layer. Nano imprint lithography and hydrothermal growth were employed to fabricate selectively grow n TiO2 nanorod substrates. The fabricated solar cell exhibits an efficiency of 19.86% with a current density, open-circuit voltage, and fill factor of 23.13 mA/cm^2, 1.120 V, and 76.69%, respectively. Time-resolved photoluminescence, ultraviolet-visible (UV-Vis) spectroscopy, and the incident phot on to current efficiency (IPCE) an alysis were conducted to understand the factors resp on sible for the improvement in characteristics of the fabricated PSCs.

关键词： perovskite solar cells patter ned T1O2 nanorods nanoimprint lithography

Characteristics of damaged layer in micro-machining of copper material

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中国有色金属学会会刊：英文版 2009年第B09期19卷 295-300页

作者： Dong-Hee KWON Jeong-suk KIM Myung-Chang KANG Se-Hun KWON jong-Hwan LEE School of Mechanical Engineering Pusan National University National Core Research Center for Hybrid Materials Solution Pusan National University Department of Mechatronics Busan College of Korea Polytechnic Ⅶ

The study on damaged layer is necessary for improving the machinability in micro-machining because the damaged layer affects the micro mold life and micro machine parts. This study examined the ultra-precision micro-machining characteristics, such as cutting speed, feed rate and cutting depth, of a micro-damaged layer produced by an ultra-high speed air turbine spindle. The micro cutting force, surface roughness and plastic deformation layer were investigated according to the machining conditions. The damaged layer was measured using optical microscope on samples prepared through metallographic techniques. The scale of the damaged layer depends on the cutting process parameters, particularly, the feed per tooth and axial depth of the cut. According to the experimental results, the depth of the damaged layer is increased by increasing the feed per tooth and cutting depth, also the damaged layer occurs less in down-milling compared with up-milling during the micro-machining operation.

关键词：机械加工性微观特征损伤层铜材样品制备技术微型机器切削速度切削深度