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Geochemistry of rare earth elements in the mid-late Quaternary sediments of the western Philippine Sea and their paleoenvironmental significance

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Science China Earth Sciences 2014年第4期57卷 802-812页

作者： XU Zhaokai LI TieGang WAN ShiMing YIN XueBo JIANG FuQing sun HanJie JinYong choi DhongIl LIM Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of Sciences Department of Oceanography Kunsan National University South Sea Institute Korea Institute of Ocean Science and Technology

Based on a δ180 chronology, rare earth elements （REE） and other typical elements in sediments from core MD06-3047 in the western Philippine Sea were analyzed to constrain the provenances of the sediments and investigate quantitative changes in the Asian eolian input to the study area over the last 700 ka. Among the competing processes that might affect REE compositions, sediment provenance is the most important one. Provenance analysis suggests that the study sediments have two provenance end-members; local volcanic sources are dominant, and eolian dust from the Asian continent has a smaller contribution. During glacial periods, eolian input to the western Philippine Sea was enhanced. In contrast, material supply from local volcanics in- creased during interglacial periods. Changes in eolian input to the study area were probably related to the strength of the East Asian winter monsoon （EAWM） as well as aridity in the Asian continent on an orbital time scale, and were partly influenced by local control factors on shorter time scales. Therefore, we propose that the present study expands the application of the REE-based method for quantitatively estimating the eolian component from the mid-latitude northern Pacific to the low-latitude western Pacific. Additionally, the study preliminarily confirms the influence of EAWM-transported eolian materi- al on sedimentation in the western Philippine Sea since 700 ka.

关键词： eolian dust sediment provenance rare earth elements East Asian winter monsoon glacial/interglacial cycle western Philippine Sea

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A study on effects of ceramic foam filter on flow aspect through water modeling experiment

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China Foundry 2017年第3期14卷 216-225页

作者： Ho-Young Hwang Cheol-Hee Nam Young-Sim choi Jun-Ho Hong Xun sun Cyber Manufacturing Process Group Korea Institute of Industrial Technology Incheon 21999 South Korea Department of Robotics and Virtual Engineering Korea University of Science and Technology Daejeon 34113 South Korea Materials Science and Engineering Kyoto University Kyoto 606-8501 Japan Shenyang Research Institute of Foundry Shenyang 110022 China

Casting defects that are closely related to entrapped air bubbles and metallic oxides occur very frequently in the sand mold casting process. Many researchers have shown that these defects can be reduced by adopting an appropriate gating system design. However, it is difficult for field engineers to identify a specific gating system that is more appropriate for their products. In this study, we tried to draw a comparison between two gating system designs with and without a ceramic foam filter. The ceramic foam filter was added to the horizontal runner just after the down sprue to prevent air bubble generation and reduce turbulence without a change of gating system design. The water modeling experiment was conducted with four different amounts of the initial volumes of water in the reservoir to verify the effects of initial pouring velocity. The results of the experiment applying the filter showed remarkably changed flow characteristics. The use of the filter was found to convert the flow pattern of water in the desired direction. The ceramic foam filter performed well to reduce flow velocity and stabilize the water *** flow pattern without a filter can be improved significantly even with the the use of just a 10 PPI irregular filter. Although the study confirmed that use of the filter may change the flow characteristics, it needs to be noted that the use of the ceramic filter alone cannot solve all the problems caused by a poorly designed gating system.

关键词： ceramic foam filter sprue gating system design sand mold casting casting defect

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Collision tumor of hepatocellular carcinoma and neuroendocrine carcinoma involving the liver: Case report and review of the literature

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World Journal of Gastroenterology 2016年第41期22卷 9229-9234页

作者： Gyu Ho choi sun Young Ann Soon Il Lee Suk BaeKim Il Han Song Dankook University College of Medicine Cheonan 31116South Korea

Primary hepatic neuroendocrine carcinoma(NEC) with concurrent occurrence of hepatocellular carcinoma(HCC) of the liver is very rare. Only 8 cases have been reported in the literature. Concurrent occurrence of HCC and NEC in the liver is classified as combined type or collision type by histological distributional patterns; only 2 cases have been reported. Herein, we report a case of collision type concurrent occurrence of HCC and NEC, in which primary hepatic NEC was in only a small portion of the nodule, which is different from the 2 previously reported cases. A 72-year-old male with chronic hepatitis C was admitted to our hospital for a hepatic mass detected by liver computed tomography(CT) at another clinic. Because the nodule was in hepatic segment 3 and had proper radiologic findings for diagnosis of HCC, including enhancement in the arterial phase and wash-out in the portal and delay phases, the patient was treated with laparoscopic left lateral sectionectomy. The pathology demonstrated that the nodule was 2.5 cm and was moderately differentiated HCC. However, a 3 mm-sized focal neuroendocrine carcinoma was also detected on the capsule of the nodule. The tumor was concluded to be a collision type with HCC and primary hepatic NEC. After the surgery, for follow-up, the patient underwent a liver CT every 3 mo. Five multiple nodules were found in the right hepatic lobe on the follow-up liver CT 6 mo post-operatively. As the features of the nodules in the liver CT and MRI were different from that of HCC, a liver biopsy was performed. Intrahepatic recurrent NEC was proven after the liver biopsy, which showed the same pathologic features with the specimen obtained 6 mo ago. Palliative chemotherapy with a combination of etoposide and cisplatin has been administered for 4 months, showing partial response.

关键词： Collision tumor Hepatocellular carcinoma Neuroendocrine carcinoma Chronic hepatitis C

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Dual function of a high-contrast hydrophobic-hydrophilic coating for enhanced stability of perovskite solar cells in extremely humid environments

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Nano Research 2017年第11期10卷 3885-3895页

作者： Jin sun Yoo Gill Sang Han Seongha Lee Min Cheol Kim Mansoo choi Hyun Suk Jung Jung-Kun Lee School of Advanced Materials Science amp Engineering Sungkyunkwan University Suwon 440-746 Republic of Korea Department of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh Pennsylvania 15261 USA Department of Mechanical and Aerospace Engineering Seoul National University Seoul 08826 Republic of Korea

In spite of a continuous increase in their power conversion efficiency （PCE） and an economically viable fabrication process,organic-inorganic perovskite solar cells （PSCs） pose a significant problem when used in practical applications：They show fast degradation of the PCE when exposed to very humid *** this study,the stability of PSCs under very humid conditions is greatly enhanced by coating the surface of the PSC devices with a multi-layer film consisting of ultrahydrophobic and relatively hydrophilic layers.A hydrophobic composite of poly（methyl methacrylate）（PMMA）,polyurethane （PU）,and SiO2 nanoparticles successfully retards the water molecules from very humid ***,the hydrophilic layer with moderately PMMA captures the residual moisture within the perovskite layer;subsequently,the perovskite layer *** dual function of the coating film keeps the PCE of PSCs at 17.3% for 180 min when exposed to over 95% humidity.

关键词： perovskite solar cell stability surface coating ultrahydrophobic self-recovery

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Improvement of machining quality of copper-plated roll mold by controlling temperature variation

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 37-41页

作者： Tae-Jin JE Eun-Chae JEON Sang-Cheon PARK Doo-sun choi Kyung-Hyun WHANG Myung-Chang KANG Division of Nano-Mechanical Systems Korea Institute of Machinery and Materials Daejeon 305-343 Korea National Core Research Center for Hybrid Materials Solution Pusan National University

Micro prism film used in LCD industry can be manufactured by roll to roll method with copper-plated roll mold. As copper-plated roll mold is getting larger, pitch error is getting severer. The pitch error drops the quality of micro prism film. The main cause of the pitch error was investigated during machining large roll mold whose machined length was 1 200 mm. The temperature of machining system was elevated during machining roll mold, and this elevation induced thermal expansion of the system. The temperature variation around the roll mold also made thermal expansion of the roll mold. The amount of thermal expansion had strong relationship to the amount of pitch error. Therefore, the roll mold was machined after warming-up of machining system and precise temperature controller around copper-plated roll mold was installed, which minimized the temperature variation. Finally, precise micro prism patterns without pitch error were machined on the large roll mold.

关键词： copper-plated roll mold machining prism pattern temperature variation

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Expression of apoptosis-related factors in chronic cyclosporine nephrotoxicity after cyclosporine withdrawal

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Acta Pharmacologica Sinica 2004年第4期25卷 3-13页

作者： sun-woo LIM,Bo-kyung sun,Bum-soon choi,Sylvia GLOWACKA,Alison J COX,Darren J KELLY,Yong-soo KIM,Jin KIM,Byung-kee BANG,Chul-woo YANG Departments of Internal Medicine the Catholic University of Korea Seoul137-040 Korea Departments of Internal Medicine the Catholic University of Korea Seoul137-040 Korea Departments of Internal Medicine the Catholic University of Korea Seoul137-040 Korea Department of Medicine St Vincent’s Hospital Fitzroy University of Melbourne Australia Department of Medicine St Vincent’s Hospital Fitzroy University of Melbourne Australia Department of Medicine St Vincent’s Hospital Fitzroy University of Melbourne Australia Departments of Internal Medicine the Catholic University of Korea Seoul137-040 Korea Departments of Anatomy the Catholic University of Korea Seoul137-040 Korea Departments of Internal Medicine the Catholic University of Korea Seoul137-040 Korea Departments of Internal Medicine the Catholic University of Korea Seoul137-040 Korea MD PhD

AIM: To examine whether the reversibility of chronic cyclosporine A (CsA) nephrotoxicity is associated with apoptotic cell death and its regulatory factors. METHODS: Chronic CsA nephrotoxicity was induced in Sprague- Dawley rats by administering CsA (15 mg/kg, sc) for 5 weeks, and then withdrawing it for 5 or 10 weeks. The effect of CsA withdrawal on apoptotic cell death was evaluated by an in situ TdT-mediated deoxyuridine triphos- phate-biotin nick end-labeling (TUNEL) assay and the expression of pro-apoptotic [(transforming growth factor- beta1 (TGF-β1) and Fas] and anti-apoptotic [epidermal growth factors (EGF) and Bcl-2] factors. RESULTS: Discontinuation of CsA induced significant decreases in TUNEL-positive cells in a time-dependent manner and the reduction in TUNEL-positive cells was correlated with the tubulointerstitial fibrosis score (r=0.919, P<0.01). Upregulation of TGF-β1 and Fas expression in CsA-treated rat kidneys was decreased significantly after with- drawal of CsA. In contrast, downregulated EGF and Bcl-2 expression returned to normal or supernormal levels. CONCLUSION: CsA withdrawal is associated with a decrease in apoptotic cell death and with changes in the expression of pro-apoptotic and anti-apoptotic molecules involved in renal wound repair. This may constitute one of the mechanisms underlying the reversibility of chronic CsA nephrotoxicity.

关键词： cyclosporine apoptosis bcl-2 fas epidermal growth factor transforming growth factor-beta fibrosis

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PIF1 Regulates Plastid Development by Repressing Photosynthetic Genes in the Endodermis

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Molecular Plant 2016年第10期9卷 1415-1427页

作者： Keunhwa Kim Jinkil Jeong Jeongheon Kim Nayoung Lee Mi Eon Kim Sangil Lee sun Chang Kim Giltsu choi Department of Biological Sciences Korea Advanced Institute of Science and Technology (KAIST) Daejeon 305-701 Republic of Korea Center for Gas Analysis Division of Metrology for Quality of Life Korea Research Institute of Standards and Science (KRISS) Daejeon 305-340 Republic of Korea

Mutations in Phytochrome Interacting Factors （PIFs） induce a conversion of the endodermal amyloplasts necessary for gravity sensing to plastids with developed thylakoids accompanied by abnormal activation of photosynthetic genes in the dark. In this study, we investigated how PIFs regulate endodermal plastid development by performing comparative transcriptome analysis. We show that both endodermal expression of PIF1 and global expression of the PIF quartet induce transcriptional changes in genes enriched for nuclear-encoded photosynthetic genes such as LHCA and LHCB. Among the 94 shared differentially expressed genes identified from the comparative transcriptome analysis, only 14 genes are demonstrated to be direct targets of PIF1, and most photosynthetic genes are not. Using a co-expression analysis, we identified a direct target of PIF, whose expression pattern shows a strong negative correlation with many photo- synthetic genes. We have named this gene REPRESSOR OF PHOTOSYNTHETIC GENES1 （RPGE1）. Endodermal expression of RPGE1 rescued the elevated expression of photosynthetic genes found in the pff quadruple （pifQ） mutant and partly restored amyloplast development and hypocotyl negative gravitropism. Taken together, our results indicate that RPGE1 acts downstream of PIF1 in the endodermis to repress photosynthetic genes and regulate plastid development.

关键词： phytochrome PIF1 hypocotyl negative gravitropism photosynthetic gene

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Optimally arranged TiO_(2)@MoS_(2) heterostructures with effectively induced built-in electric field for high-performance lithium-sulfur batteries

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能源化学:英文版 2023年第8期83卷 496-508,I0012页

作者： Jeongyoub Lee Changhoon choi Jung Been Park Seungho Yu Jinho Ha Hyungsoo Lee Gyumin Jang Young sun Park Juwon Yun Hayoung Im Subin Moon Soobin Lee Jung-Il choi Dong-Wan Kim Jooho Moon Department of Materials Science and Engineering Yonsei UniversitySeoul 03722Republic of Korea School of Civil Environmental and Architectural EngineeringKorea UniversitySeoul 02841Republic of Korea Energy Storage Research Center Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea School of Mathematics and Computing(Computational Science and Engineering) Yonsei UniversitySeoul 03722Republic of Korea

To overcome the serious technological issues affecting lithium-sulfur(Li-S) batteries,such as sluggish sulfur redox kinetics and the detrimental shuttle effect,heterostructure engineering has been investigated as a strategy to effectively capture soluble lithium polysulfide intermediates and promote their conversion reaction by integrating highly polar metal oxides with catalytically active metals ***,to fully exploit the outstanding properties of heterostructure-based composites,their detailed structure and interfacial contacts should be designed ***,optimally arranged TiO_(2)and MoS_(2)-based heterostructures(TiO_(2)@MoS_(2)) are fabricated on carbon cloth as a multifunctional interlayer to efficiently trap polysulfide intermediates and accelerate their redox *** to the synergistic effects between TiO_(2)and MoS_(2)and the uniform heterointerface distribution that induces the ideally oriented built-in electric field,Li-S batteries with TiO_(2)@MoS_(2)interlayers exhibit high rate capability(601 mA h g^(-1)at 5 C),good cycling stability(capacity-fade rate of 0.067% per cycle over 500 cycles at2 C),and satisfactory areal capacity(5.2 mA h cm^(-2)) under an increased sulfur loading of 5.2 mg cm^(-2).Moreover,by comparing with a MoS_(2)@TiO_(2)interlayer composed of reversely arranged heterostructures,the effect of the built-in electric field’s direction on the electrocatalytic reactions of polysulfide intermediates is thoroughly investigated for the first *** superior electrocatalytic activities of the rationally arranged TiO_(2)@MoS_(2)interlayer demonstrate the importance of optimizing the built-in electric field of heterostructures for producing high-performance Li-S batteries.

关键词： Lithium-sulfur batteries Shuttle effect TiO_(2)-MoS_(2)heterostructure engineering Built-in electric field Multifunctional interlayers

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Influence of tool deflection on micro channel pattern of 6:4 brass with rectangular tool

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中国有色金属学会会刊：英文版 2009年第B09期19卷 164-170页

作者： Tae-Jin JE Kang-Won LEE Sang-Cheon PARK Jae-Gu KIM Doo-sun choi Kyoung-Taik PARK Kyung-Hyun WHANG Nano Mechanical Systems Research Division Korea Institute of Machinery & Materials (KIMM)

Machining experiment of micro channel structure with 6:4 brass was carried out by shaping process using a single crystal diamond tool. FEM simulation using solid cantilever beam model was analyzed. In result of experiment, tool deflection is observed as machining characteristics through result of experiments such as surface roughness, cutting force and burr formations. And the influence of tool deflection is experimentally proved.

关键词：金刚石工具挠度通道模式黄铜矩形实验证明加工特性有限元模拟

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Machining characteristics of complex prism pattern on electroplated roll by copper

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中国有色金属学会会刊：英文版 2009年第B09期19卷 288-294页

作者： Tae-Jin JE Sang-Cheon PARK Kang-Won LEE Yeong-Eun YOO Doo-sun choi Kyung-Hyun WHANG Myung-Chang KANG Nano-Machining Laboratory Division of Nano-Mechanical Systems Korea Institute of Machinery and Materials Nano-Mechatronics Department University of Science and TechnologySinseongnoYouseong-GuDaejeonKorea National Core Research Center for Hybrid Materials Solution Pusan National University

The BLU (back light unit) is the core component of the LCD for notebook, mobile-phone, navigation, as well as large sized TV, PID (public information display), etc. In order to enhance optical efficiency of LCD, optical films with the uniform prism patterns have been used for BLU by stacking two films up orthogonally. In this case, light interference-phenomenon occurred such as Morie, wet-out, u-turning, etc. It caused several problems such as low brightness, spots and stripes in LCD. Recently, the high-luminance micro complex prism patterns are actively studied to avoid the light interference-phenomenon and enhance the optical efficiency. In this study, the roll master to manufacture complex micro prism pattern film was machined by using the high precision lathe. The machined patterns on the roll master were 50, 45, 40, 35, 30, 25, 20, 15, 10 and 5 μm in the pitch with 25.0, 22.5, 20.0, 17.5, 15.0, 12.5, 10.0, 7.5, 5.0 and 2.5 μm in the peak height, respectively. The roll was 2 000 mm in length and 320 mm in diameter. The electroplated roll by copper and the natural single crystal diamond tool was used for machining the patterns. The cutting force was measured and analyzed for each cutting condition by using the dynamometer. The chips and the surfaces after being machined were analyzed by SEM and microscope.

关键词：车床加工微棱镜铜电镀特征光学效率光学薄膜笔记本电脑金刚石工具

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