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UBVVI Surface Photometry of the Spiral Galaxy NGC 300 in the Sculptor Group

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Chinese Journal of Astronomy and Astrophysics 2004年第4期4卷 299-310页

作者： sang Chul Kim Hwankyung Sung Hong Soo park Eon-Chang Sung Korea Astronomy Observatory Taejon 305-348Republic of KoreaDepartment of Astronomy and Space ScienceSejong University98 Gunja-dongGwangjin-guSeoul 143-747Republic of KoreaAstronomy ProgramSEESSeoul National UniversitySeoul 151-742Republic of KoreaKorea Astronomy ObservatoryTaejon 305-348Republic of Korea

We present UBVI surface photometry over a 20.5' × 20.5' area of the late-type spiral galaxy NGC 300. We have derived isophotal maps, surface brightness profiles, ellipticity profiles, position angle profiles, and color profiles. By merging our I-band measurements with those of Boker et al. based on Hubble Space Telescope observations, we have obtained combined I-band surface brightness profiles for the region 0.02' < r < 500' and have decomposed the profiles into three components: a nucleus, a bulge, and an exponential disk.

关键词： galaxies: spiral - galaxies: photometry - galaxies: individual(NGC 300) - galaxies: nuclei

RTV silicone rubber composites reinforced with carbon nanotubes,titanium-di-oxide and their hybrid:Mechanical and piezoelectric actuation performance

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Nano Materials Science 2021年第3期3卷 233-240页

作者： Vineet Kumar Anuj Kumar Sung Soo Han sang-Shin park School of Mechanical Engineering Yeungnam UniversitySouth Korea School of Chemical Engineering Yeungnam UniversitySouth Korea

The use of nanofillers with high surface area and extreme purity in polymer composite is an effective strategy to obtain high performance polymeric ***,the effect of nanofillers such as carbon nanotubes(CNT),titanium dioxide(TiO_(2)),and their hybrid on rubber-based composites was *** this study,rubber nanocomposites were fabricated by using room temperature vulcanized(RTV)silicone rubber matrix and nanofillers(***,TiO_(2),and CNT-TiO_(2))through solution casting ***,the purity and surface area of CNT(purity:>96%and BET surface area:300 m2/g)and TiO_(2)(purity:>98%and BET surface area:165 m2/g)were estimated by field emission scanning electron microscopy/energy dispersive X-ray(FESEM-EDX)and adsorption *** mechanical properties of the rubber nanocomposites were enhanced by incorporating *** compressive modulus was 2.18 MPa for unfilled composites and increased to 6.8 MPa(CNT),3.95 MPa(CNT-TiO_(2)),and 2.44 MPa(TiO_(2))at 5 phr,***,the tensile strength was 0.54 MPa for unfilled composites and increased to 1.37 MPa(CNT),1.33 MPa(CNT-TiO_(2))and 0.61 MPa(TiO_(2))at 5 phr,***,the actuation displacement was improved with increasing input voltage and it was 2 mm for CNT,1.6 mm for CNT-TiO_(2) hybrid and 0.5 mm for TiO_(2) at 10 ***,a series of experiments show the potential application in piezoelectric actuation.

关键词： Multi-walled carbon nanotubes Titanium dioxide Hybrid Mechanical properties Piezoeletric actuation

Inhibitory effects of coronary vasodilator papaverine on heterologously-expressed HERG currents in Xenopus oocytes

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Acta Pharmacologica Sinica 2007年第4期28卷 503-510页

作者： Cuk-seong KIM Nam LEE Sook-jin SON Kyu-seung LEE hyo-shin KIM Yong-geun KWAK Soo-wan CHAE sang-do LEE Byeong-hwa JEON Jin-bong park Department of Physiology College of MedicineChungnam National UniversityDaejeon 301131Korea Department of Pharmacology Chonbuk National UniversityMedical SchoolChonju 561-180Korea

Aim:To characterize the effects of papaverine on HERG channels expressed inXenopus oocytes as well as cardiac action potential in rabbit ventricular ***:Conventional microelectrodes were used to record action potential inrabbit ventricular *** currents were recorded by 2-electrode voltageclamp technique in Xenopus oocytes injected with HERG ***:Papa-verine increased the cardiac action potential duration in rabbit ventricular *** blocked heterologously-expressed HERG currents in a concentration-depen-dent manner (IC5071.03±4.75 μmol/L,NH 0.80,n=6),whereas another phosphodi-esterase inhibitor,theophylline （500 μmol/L）,did *** blockade of papaverineon HERG currents was not *** slope conductance measuredas a slope of the fully activated HERG current-voltage curves decreased from78.03±4.25 μS of the control to 56.84±5.33,36.06±6.53,and 27.09±5.50 μS （n=4） by30,100,and 300 μmol/L of papaverine,*** （100 μmol/L）caused a 9 mV hyperpolarizing shift in the voltage-dependence of steady-stateinactivation,but there were no changes in the voltage-dependence of HERG cur-rent *** blocked HERG channels in the closed,open,andinactivated ***:These results showed that papaverine blockedHERG channels in a voltage-and state-independent manner,which may mostlikely be the major mechanism of papaverine-induced cardiac arrhythmia reportedin humans.

关键词： papaverine HERG cardiac action potential

Influence of undissolved second-phase particles on dynamic recrystallization behavior of Mg–7Sn–1Al–1Zn alloy during low-and high-temperature extrusions

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Journal of Materials Science & Technology 2021年第12期71卷 87-97页

作者： Hyun Ji Kim sang-Cheol Jin Jae-Gil Jung Sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu41566Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon51508Republic of Korea

This study investigates the effects of fine and coarse undissolved particles in a billet of the Mg–7 Sn–1 Al–1 Zn(TAZ711)alloy on the dynamic recrystallization(DRX)behavior during hot extrusion at low and high temperatures and the resultant microstructure and mechanical properties of the *** this end,partially homogenized(PH)and fully homogenized(FH)billets are extruded at temperatures of250 and 450°*** PH billet contains fine and coarse undissolved Mg_(2) Sn particles in the interdendritic region and along the grain boundaries,*** fine particles(<1μm in size)retard DRX during extrusion at 250°C via the Zener pinning effect,and this retardation causes a decrease in the area fraction of dynamically recrystallized(DRXed)grains of the extruded *** addition,the inhomogeneous distribution of fine particles in the PH billet leads to the formation of a bimodal DRXed grain structure with excessively grown grains in particle-scarce *** contrast,in the FH billet,numerous nanosized Mg_(2) Sn precipitates are formed throughout the material during extrusion at 250°C,which,in turn,leads to the formation of small,uniform DRXed grains by the grain-boundary pinning effect of the *** the PH billet is extruded at the high temperature of 450°C,the retardation effect of the fine particles on DRX is weakened by their dissolution in theα-Mg matrix and the increased extent of thermally activated grain-boundary *** contrast,the coarse Mg_(2) Sn particles in the billet promote DRX during extrusion through the particle-stimulated nucleation phenomenon,which results in an increase in the area fraction of DRXed *** both low and high extrusion temperatures,the extruded material fabricated using the PH billet,which contains both fine and coarse undissolved particles,has a lower tensile strength than that fabricated using the FH billet,which is virtually devoid of second-phase *** lower strength of the former is attributed mai

关键词： Mg–Sn alloy Second-phase particle Extrusion Homogenization Dynamic recrystallization

HOS1 Facilitates the Phytochrome B-Mediated Inhibition of PIF4 Function during Hypocotyl Growth in Arabidopsis

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Molecular Plant 2017年第2期10卷 274-284页

作者： Ju-Heon Kim hyo-Jun Lee Jae-Hoon Jung sangmin Lee Chung-Mo park Department of Chemistry Seoul National University Seoul 08826 Korea Sainsbury Laboratory University of Cambridge Cambridge CB2 1LR UK Plant Genomics and Breeding Institute Seoul National University Seoul 08826 Korea These authors contributed equally to this article Present address: SK Innovation Daejeon 34124 Korea

Upon exposure to light, developing seedlings undergo photomorphogenesis, as illustrated by inhibition of hypocotyl elongation, cotyledon opening, and leaf greening. During hypocotyl photomorphogenesis, light signals are sensed by multiple photoreceptors, among which the red/far-red light-sensing phytochromes have been extensively studied. However, it is not fully understood how the phytochromes modulate hypo- cotyl growth. Here, we demonstrated that HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1 （HOS1）, which is known to either act as E3 ubiquitin ligase or affect chromatin organization, inhibits the transcriptional activation activity of PHYTOCHROME INTERACTING FACTOR 4 （PIF4）, a key transcrip- tion factor that promotes hypocotyl growth. Consistent with the negative regulatory role of HOSl in hypo- cotyl growth, HOSl-defective mutants exhibited elongated hypocotyls in the light. Notably, phyB induces HOS1 activity in inhibiting PIF4 function. Taken together, these observations provide a molecular basis for the phyB-mediated suppression of hypocotyl growth in Arabidopsis.

关键词： photomorphogenesis hypocotyl growth phytochrome signaling HOS1 PIF4

A feasible route to produce 1.1 GPa ferritic-based low-Mn lightweight steels with ductility of 47%

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Journal of Materials Science & Technology 2022年第22期117卷 225-237页

作者： Kwang Kyu Ko hyo Ju Bae Eun Hye park Hyeon-Uk Jeong hyoung Seok park Jae Seok Jeong Jung Gi Kim hyokyung Sung Nokeun park Jae Bok Seol Department of Materials Engineering and Convergence Technology Center for K-metalGyeongsang National University(GNU)Jinju 52828South Korea School of Materials Science and Engineering Yeungnam UniversityGyeongbuk 38541South Korea Materials Research Team R&D Hyundai MobisYongin 16891South Korea Materials Technology Development Team Doosan Heavy Industries&ConstructionChangwon 51711South Korea

High- and medium-Mn (H/M-Mn) base lightweight steels are a class of ultrastrong structural materials with high ductility compared to their low-Mn counterparts with low strength and poor ***, producing these H/M-Mn materials requires the advanced or high-tech manufacturing techniques, which can unavoidably provoke labor and cost concerns. Herein, we have developed a facilestrategy that circumvents the strength–ductility trade-off in low-Mn ferritic lightweight steels, by employing low-temperature tempering-induced partitioning (LTP). This LTP treatment affords a typical Fe-2.8Mn-5.7Al-0.3C (wt.%) steel with a heterogeneous size-distribution of metastable austenite embeddedin a ferrite matrix for partitioning more carbon into smaller austenite grains than into the larger austenite ones. This size-dependent partitioning results in slip plane spacing modification and lattice strain,which act through dislocation engineering. We ascribe the simultaneous improvement in strength andtotal elongation to both the size-dependent dislocation movement in austenite grains and the controlleddeformation-induced martensitic transformation. The low-carbon-partitioned large austenite grains increase the strength and ductility as a consequence of the combined martensitic transformation andhigh dislocation density-induced hardening and by interface strengthening. Additionally, high-carbonpartitioned small austenite grains enhance the strength and ductility by planar dislocation glide (inthe low strain regime) and by cross-slipping and delayed martensitic transformation (in the high strainregime). The concept of size-dependent dislocation engineering may provide different pathways for developing a wide range of heterogeneous-structured low-Mn lightweight steels, suggesting that LTP maybe desirable for broad industrial applications at an economic cost.

关键词： Low-Mn lightweight steel Carbon partitioning Metastable austenite Dislocation movement

Another new variant of Bouveret's syndrome

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World Journal of Gastroenterology 2009年第3期15卷 378-379页

作者： Seong-Heum park sang-Woo Lee Tae-Jin Song Department of Surgery Korea UniversityAnsan Hospital516Gojan-dongDanwon-guAnsanGyeonggi-do 425-707South Korea Department of Gastroenterology Korea UniversityAnsan Hospital516Gojan-dongDanwon-guAnsanGyeonggi-do 425-707South Korea

Although Bouveret's syndrome,*** outlet obstruction by a large gallstone impacted in the proximal duodenum secondary to a cholecystoduodenal fistula,is rare,its pathogenesis and clinical features are well ***,existence of variant forms of the syndrome are not well known,and as far as we know,only two cases of variant Bouveret's syndrome have been described in the English-language *** present a case of another new variant of Bouveret's syndrome in a 54-year-old Korean woman.

关键词： Duodenal obstruction Biliary fistula Gallstones

miR-215 overexpression distinguishes ampullary carcinomas from pancreatic carcinomas

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Hepatobiliary & Pancreatic Diseases International 2015年第3期14卷 325-329页

作者： Dong Ho Choi sang Jae park Hark Kyun Kim Department of Surgery Hanyang University School of Medicine Center for Liver Cancer National Cancer Center Biomolecular Function Research Branch National Cancer Center

Distinguishing ampullary carcinoma from pancreatic carcinoma is important because of their different prognoses. microRNAs are differentially expressed according to the tissue of origin. However, there is rare research on the differential diagnosis between the two types of cancers by microRNA in periampullary cancers. The present study was undertaken to compare microRNA profiles between ampullary and pan- creatic carcinomas using microarrays, miR-215 was most significantly overexpressed in ampullary carcinomas; whereas the expressions of miR-134 and miR-214 were significantly lower in ampuUary carcinomas than in pancreatic carcino- mas. When these discriminatory microRNAs were applied to liver metastases, they were correctly predicted for the tissue of origin. Although this study is limited by small sample size, striking difference in microRNA expression and concordant expression of discriminating microRNAs in primary tumors and metastases suggest that these novel discriminatory mi- croRNAs warrant future validation.

关键词： ampulla of Vater pancreatic cancer gene expression

Microstructure and Mechanical Properties of TiB-Containing Al–Zn Binary Alloys

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Journal of Materials Science & Technology 2016年第7期32卷 653-659页

作者： sang-Soo Shin Gil-Yong Yeom Tae-Yang Kwak Ik-Min park Department of Materials Science and Engineering Pusan National University Busan 609-735 Republic of Korea Liquid Processing & Casting Technology R&BD Group Korea Institute of Industrial Technology Incheon 21999 Republic of Korea

The microstructure and mechanical properties of newly developed Al-35Zn cast alloys with TiB refiner addition were evaluated by X-ray diffractometry, optical microscopy, and scanning electron microscopy coupled with energy dispersive spectrometry. The microstructure of these alloys featured α-Al den- drites surrounded by AI-Zn （α ＋ rI） eutectic structures. After the addition of TiB refiner, the alloy grain sizes decreased, and its morphology abruptly changed from dendritic to equiaxed grains. Such an im- proved microstructure of the modified alloys was accompanied by a significant increase in the tensile strength and elongation percentage compared to those of the AI-Zn or Zn-Al-based alloys. The results showed that with the increase of TiB content up to 0.05%, the morphology of α-Al dendrites and α ＋ T1 phases changed from coarse dendrite and lamellar structures into independent and fine ones. Based on these results, the effect of TiB refiner addition on the microstructure and mechanical properties of the AI-35Zn binary alloys was investigated.

关键词： Al-Zn(-Cu) alloyEutectic structureHigh strengthTiB2