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Structural Study of the Oxidized High Modulus Carbon Fiber using Laser Raman Spectroscopy

  • Roh, Jae-Seung;Kim, Suk-Hwan
    • Carbon letters
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    • v.10 no.1
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    • pp.38-42
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    • 2009
  • This study aims to find a correlation between XRD and Raman result of the oxidized high modulus carbon fibers as a function of its oxidation degrees, and compare with the isotropic carbon fiber reported early. La of the high modulus carbon fiber prepared by oxidation in carbon dioxide gas have been observed using laser Raman spectroscopy. The basic structural parameters of the fibers were evaluated by XRD as well. The La of the original high modulus carbon fibers were measured to be 144 ${\AA}$ from Raman analysis and 135 ${\AA}$ from XRD analysis. La of the 92% oxidized fiber were 168 ${\AA}$ by using Raman and 182 ${\AA}$ by using XRD. There was some correlation between the La value obtained from Raman and XRD. However the La value changes of the high modulus carbon fiber through whole oxidation process showed opposite tendency compare with the isotropic carbon fiber because of the fiber structure basically.

Metal-Ion Interactions with Sugars. The Crystal Structure of CaCl2-Fructose Complex

  • Guo, Jianyu;Lu, Yan;Whiting, Roger
    • Bulletin of the Korean Chemical Society
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    • v.33 no.6
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    • pp.2028-2030
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    • 2012
  • The single-crystal structure of $CaCl_2{\cdot}2C_6H_{12}O_6{\cdot}3H_2O$ was determined with Mr=525.34, a=16.054(7) ${\AA}$, b=7.864(4) ${\AA}$, c=10.909(5) ${\AA}$, ${\beta}=127.894(8)^{\circ}$, V=1086.9(9) ${\AA}^3$, C2, Z=2 and $R$=0.0227 for 1727 observed reflections. The fructose moiety of the complex exists as a ${\beta}$-D-pyranose. The calcium ion is surrounded by eight oxygen atoms, These are arranged in symmetry-related pairs derived from four sugar and two water molecules. Three nonvicinal hydroxyl groups of fructose are involved in calcium binding. All the hydroxyl groups and water molecules are involved in forming an extensive hydrogen-bond network.

Magnetostriction and Stress of NiFeCr/(Cu/Co90Fe10)×N/NiFeCr Multilayer Films (NiFeCr/(Cu/Co90Fe10)×N/NiFeCr 다층박막의 자기변형과 응력에 관한 연구)

  • Jo, Soon-Chul
    • Journal of the Korean Magnetics Society
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    • v.20 no.1
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    • pp.8-12
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    • 2010
  • The magnetostriction and stress of multilayer $NiFeCr/(Cu/Co_{90}Fe_{10}){\times}N/NiFeCr$ films were investigated. As the number of Cu $15{\AA}$/CoFe $15{\AA}$ bilayers was increased, the saturation magnetostriction decreased from $-5.6\times10^{-6}$ at 2 bilayers to $-8.5\times10^{-6}$ at 20 bilayers. A change of CoFe thickness from 10 to $20{\AA}$ caused a decrease in the magnitude of tensile stress from 980MPa to 590MPa as the number of Cu $15{\AA}$/CoFe $15{\AA}$ bilayers increased from 2 to 20. The maximum magnetostrictive anisotropy field that could be developed due to nonzero magnetostriction and stress is calculated to be 135.7 Oe when the number of Cu $15{\AA}$/CoFe $15{\AA}$ bilayers is 10.

Nuclear Factor-${\kappa}B$ Dependent Induction of TNF-${\alpha}$ and IL-$1{\beta}$ by the Aggregatibacter actinomycetemcomitans Lipopolysaccharide in RAW 264.7 Cells

  • Na, Hee Sam;Jeong, So Yeon;Park, Mi Hee;Kim, Seyeon;Chung, Jin
    • International Journal of Oral Biology
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    • v.39 no.1
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    • pp.15-22
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    • 2014
  • Aggregatibacter actinomycetemcomitans is an important pathogen in the development of localized aggressive periodontitis. Lipopolysaccharide (LPS) is a virulent factor of periodontal pathogens that contributes to alveolar bone loss and connective tissue degradation in periodontal disease. Our present study was designed to investigate the cytokine expression and signaling pathways regulated by A. actinomycetemcomitans LPS (Aa LPS). Cytokine gene expression profiling in RAW 264.7 cells was performed by microarray analyses. The cytokine mRNA and protein levels and related signaling pathways induced by Aa LPS were measured by RT-PCR, ELISA and western blotting. Microarray results showed that Aa LPS strongly induced the expression of NF-${\kappa}B$, NF-${\kappa}B$-related genes, inflammatory cytokines, TNF-${\alpha}$ and IL-$1{\beta}$ in RAW 264.7 cells. NF-${\kappa}B$ inhibitor pretreatment significantly reduced the levels of TNF-${\alpha}$ and IL-$1{\beta}$ mRNA and protein. In addition, the Aa LPS-induced TNF-${\alpha}$ and IL-$1{\beta}$ expression was inhibited by p38/JNK MAP kinase inhibitor pretreatment. These results show that Aa LPS stimulates TNF-${\alpha}$ and IL-$1{\beta}$ expression through NF-${\kappa}B$ and p38/JNK activation in RAW 264.7 cells, suggesting the essential role of this pathway in the pathogenesis of localized aggressive periodontitis.

Structure-Related Cytotoxicity and Anti-Hepatofibric Effect of Asiatic Acid Derivatives in Rat Hepatic Stellate Cell-Line, HSC-T6

  • Dong, Mi-Sook;Jung, Seung-Hyun;Kim, Hyun-Jung;Kim, Jeong-Ran;Zhao, Long-Suan;Lee, Eung-Seok;Lee, Eun-Joo;Yi, Jung-Bum;Lee, Nam-Kyu;Cho, Yong-Baik;Kwak, Wie-Jong;Park, Young-In
    • Archives of Pharmacal Research
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    • v.27 no.5
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    • pp.512-517
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    • 2004
  • The structural relationship of 16 asiatic acid (AA) derivatives, including AA and asiaticoside (AS) to cytotoxicity and anti-hepatofibrotic activity in HSC-T6 cells, were investigated. Cytotoxicities of AA derivatives varied from 5.5 $\mu$M to over 2000 $\mu$M of $IC_{50}$/ depending on AA functional group modifications. Substituting the hydroxyl group at the C(2) to N≡C and substituting bulky groups for dihydroxyl groups at (3), (23) of the A-ring increased the cytotoxicity, but keto group at C(11) and benzoyl ester at C(2) were greatly reduced it. Modification of the carboxylic acid group at C28 also reduced the cytotoxicity. The collagen synthesis determined by hydroxyproline content in the cells was inhibited from a maximum of 48% (Zlx-i-85 and 87) to 15% (AS) by AA derivatives. The anti-hepatofibrotic effect of these compounds might be due to the reduced expression of prolyl 4-hydroxylase $\alpha$ and $\beta$ subunits and TIMP2. However, the inhibition of collagen by asiaticoside derivatives did not show any structural-activity relationship.

Comparison of Immunomodualtory Effects of Water-extracted Ginseng Radix, Pilose Asia-bell, Astragali Radix, Astractylodes Rhizoma alba and Dioscoreae Rhizoma (대표적 보기약인 인삼, 당삼, 황기, 백출, 산약 물추출액의 면역조절효과 비교)

  • Shin Sang Woo;Lee Young Sun;Park Jong Hyun;Kwon Taeg Kyu;Suh Seong Il;Kwon Young Kyu
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.18 no.4
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    • pp.1140-1146
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    • 2004
  • This study was carried out to investigate the comparison of immunomodualtory effects of water-extracted Ginseng Radix(GR), Pilose Asia-bell(PA), Astragali Radix(AR), Astractylodes Rhizoma alba(AA) and Dioscoreae Rhizoma (DR). The parameter examined to assess apparent immunomodulatory effect of the water-extracted GR, PA, AR, AA and DR included the regulation of Nitric oxide (NO), the expression of Th1/Th2 type cytokine, the change of B cell phenotype. The water-extracted GR, PA, AR, AA and DR inhibited NO production and iNOS protein expression in LPS stimulated RAW 264.7 macrophage cells. In the Th1 and Th2 cytokine expression, the water-extracted GR, PA, AR, AA and DR induced IL-2 and IFNr mRNA gene expression. Therefore, it seems that the water-extracted GR, PA, AR, AA and DR have a inducing effect of Th1 type cytokines. In the Flow cytometry analysis, the water-extracted GR, PA, AR, AA and DR did not change B cell phenotype (CD45R/B220). The water-extracted GR, PA, AR, AA and DR have a reducing effect of immune suppression cause by Methotrexate (MTX), an agent of immune suppression. These results suggest that the immunomodulatory effects of the water-extracted GR, PA, AR, AA and DR may be, in part, associated with the inducing IL-2 and IFNr mRNA gene expression in and regulation of NO production in macrophage cells.

Growth of ${\gamma}$-Al2O3 (111) on an ultra-thin interfacial Al2O3 layer/NiAl(110)

  • Lee, M.B.;Frederick, B.G;Richardson, N.V.
    • Journal of Korean Vacuum Science & Technology
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    • v.2 no.2
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    • pp.63-77
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    • 1998
  • The oxidation of NiAl(110) was investigated in the temperature regime between 300K and 1300 K using LEED (low energy electron diffraction), TPD (temperature programmed desorption) and HREELS (high resolution electron energy loss spectroscopy). The adsorption of N2O and O2 up to reconstructions. Stepwise annealing of the oxygen-saturated sample from 600 K to 1300K in UHV (ultra-high vacuum,) results in firstly the onset of randomly oriented then finally fairly well-ordered. 5 ${\AA}$ Al2O3 film with quasi-hexagonal periodicity. Ordered thicker oxide films of 18-30 ${\AA}$ seem to be grown on this interfacial oxide layer by direct oxidation of sample at elevated temperature between 1150 and 1300 K because of the LEED pattern consisting of new broad hexagonal spots and the previous 5 ${\AA}$ spots. Although the periodicity of surface oxygen arrays shows no significant change from an hexagonal close-packing, the O-O distance changes from ∼3.0 ${\AA}$ film to ∼2.9 ${\AA}$ for thicker oxides. with the appearance of Auger parameter, for the 5${\AA}$ film can be described better as an interfacial oxide layer. The observation of three symmetric phonon peaks can be also a supporting evidence for this phase assignment since thicker oxide films on the Same Ni2Al3(110) show somewhat different phonon structure much closer to that of the ${\gamma}$-Al2O3. The adsorption/desorption of methanol further proves the preparation of less-defective and/or oxygen-terminated Al2O3 films showing ordered phase transitions with the change of oxide thickness between 5 ${\AA}$ to 30 ${\AA}$.

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The Effective Temperature of the N Stars (탄소성(炭素星)(N성(星))의 유효온도)

  • Lee, Young-Bom
    • Journal of The Korean Astronomical Society
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    • v.8 no.1
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    • pp.11-14
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    • 1975
  • Photoelectric observations were made of four N stars (HD 51208, HD 75021, V 1942 Sgr, and RU Vir) at careful1y chosen discrete wavelengths between $7000{\AA}\;and\;11000{\AA}$ with $30{\AA}$ bandpass width. Their effective temperatures have been derived by fitting the black-body radiation curve to the observed continuum intensities at $7800{\AA},\;9000{\AA}\;and\;10800{\AA}$. The resulting temperature ranges from $2500^{\circ}K\;to\;2900^{\circ}K.$. It is probable that almost all the N stars belong to this range of temperature. However, the temperatures of very red N stars can not be well determined due to large variability and redistribution of their radiation energy arising from the graphite shells around them.

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A Structural Study of the Activated Carbon Fibers as a Function of Activation Degrees

  • Roh, Jae-Seung;Suhr, Dong-Soo
    • Carbon letters
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    • v.5 no.2
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    • pp.51-54
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    • 2004
  • Isotropic pitch-based carbon fiber was isothermally activated in $CO_2$ atmosphere. Structural parameters of the isotropic carbon fibers and activated carbon fibers (ACFs) were evaluated by X-ray diffraction (XRD). The $d_{002}$ and La of the carbon fibers were measured to be 4.04 ${\AA}$ and 23.6 ${\AA}$ and those of ACFs were 4.29 ${\AA}$ and 22.7 ${\AA}$, respectively, representing less ordered through activation process. The pores in the ACFs were characterized by BET, and they showed super-high specific surface area of maximum value 3,495 $m^2/g$ from average pore size of 8.3 ${\AA}$ at 59% burn-off. It was recognized that 8-9 ${\AA}$ was optimum range of pore size for efficient creation of high specific surface area. The average size of the pores formed at higher temperature ($1100^{\circ}C$) was larger than that of the pores formed at lower temperature ($900^{\circ}C$).

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Comparison of Voice Outcomes between Medialization Thyroplasty and Arytenoid Adduction with or without Injection Laryngoplasty in Unilateral Vocal Fold Paralysis Patients (일측성 성대마비 환자에서 내전형 갑상성형술, 피열연골 내전술, 피열연골내전술과 성대주입술 병행치료의 음성 결과 비교)

  • Jin, Hokyung;Won, Seong Jun;Choi, Nayeon;Son, Young-Ik
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.28 no.2
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    • pp.118-122
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    • 2017
  • Background and Objectives : In unilateral vocal fold paralysis (VFP), medialization thyroplasty (MT), arytenoid adduction (AA) and injection layrngoplasty (IL) are the most common procedures to correct phonatory problems. There is no consensus that which procedure is superior to the other for correcting the glottal insufficiency. The purpose of this study was to compare the phonatory parameters between MT, AA and AA with IL (AA+IL) in patients with unilateral VFP. Materials and Methods : This retrospective study enrolled patients from 2005 to 2016. Total 72 patients (49 male, 23 female, mean age 54.5 years) were classified into three groups ; MT (n=28), AA (n=12), and AA+IL (n=32). GRBAS scales, maximum phonation time (MPT), jitter, shimmer, noise to harmonic ratio (NHR), and voice handicap index (VHI)-10 and VHI-30 were preoperatively and postoperatively collected and compared between the three groups. Results : Age, gender and cause of VFP were not significantly different between the three groups. In MT and AA groups, MPT, VHI, G (overall grade) and B (breathiness) were significantly improved. In AA+IL group, jitter, shimmer, NHR, MPT, VHI, G and B were significantly improved. In analysis of differences (pre-postoperative values), ${\Delta}$ jitter (p<0.001), ${\Delta}$ shimmer (p=0.031), and ${\Delta}$ NHR (p=0.002) were significantly different and AA+IL group showed the greatest improvement. Conclusion : Analysis of voice parameters showed that all the three procedures for patients with unilateral VFP are effective in the improvement of voice ; especially in MPT, VHI-10, G and B scales. Compared to the others, AA+IL provided the better acoustic values including jitter, shimmer and NHR.

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