• 생약학회지
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• 제42권2호
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• pp.155-160
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• 2011

In this study, we investigated on antioxidative activity, antibacterial activity against pathogens of acne and tyrosinase inhibitory activity in 75% EtOH extract and its fractions from bark of Prunus sargen tii. The total polyphenol and flavonoidcontent of the EtOAc fraction were found to be 378.0 mg/g and 67.5 mg/g as the highest content. In the measurement of DPPH radical scavenging ability, EtOAc and BuOH fraction were exhibited stronger scavenging ability than the other fractions and 75% EtOH extract. In antibacterial activity by disc diffusion assay against pathogen of acne, antibacterial activity of the EtOAc fraction and 75% EtOH extract was stronger than the other fractions. Especially, the EtOAc fraction was the highest effective fraction in the antibacterial activity. Moreover, tyrosinase inhibitory activity of EtOAc fraction, BuOH fraction and 75% EtOH extract was higher than the other fractions. In particular, tyrosinase inhibitory activity of the EtOAc fraction showed higher activity than ascorbic acid used as positive control.

• Structural Engineering and Mechanics
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• 제80권6호
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• pp.727-736
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• 2021

In this work, mathematical modeling of the passive vibration controls of a three-layered sandwich beam under hard excitation is developed. Kelvin-Voigt Viscoelastic model is considered in the core. The formulation is based on the higher-order zig-zag theories where the normal and shear deformations are taken into account only in the viscoelastic core. The dynamic behaviour of the beam is represented by a complex highly nonlinear ordinary differential equation. The method of multiple scales is adopted to solve the analytical frequency-amplitude relationships in the super-harmonic resonance case. Parametric studies are carried out by using HSDT and first-order deformation theory by considering different geometric and material parameters.

• Advances in materials Research
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• 제12권2호
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• pp.161-177
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• 2023

This paper proposes an analytical method to investigate the free vibration behaviour of new functionally graded (FG) carbon nanotubes reinforced composite beams based on a higher-order shear deformation theory. Cosine functions represent the material gradation and material properties via the thickness. The kinematic relations of the beam are proposed according to trigonometric functions. The equilibrium equations are obtained using the virtual work principle and solved using Navier's method. A comparative evaluation of results against predictions from literature demonstrates the accuracy of the proposed analytical model. Moreover, a detailed parametric analysis checks for the sensitivity of the vibration response of FG nanobeams to nonlocal length scale, strain gradient microstructure-scale, material distribution and geometry.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2001년도 춘계 수산관련학회 공동학술대회발표요지집
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• pp.132-133
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• 2001

돌김류에는 잇바디돌김 (미역김, Porphyra dentata), 둥근돌김 (P. suborbiculata), 긴잎돌김 (P. pseudolinearis), 모무늬돌김 (P. seriata) 등이 있다 (Kang and Ko, 1997). 김의 맛과 밀접한 관계가 있는 함질소엑스성분에 관한 연구는 유리아미노산 (Noda et al., 1975: Saito., 1975; Yoshie et al., 1993, Araki et al., 1996, 1997; Sakai and Kasai, 2000), ATP관련 화합물 (Fujii, 1967; Ooyama et al., 1968; Tashiro et al.,1983,1991; Araki et al.,1996) 등이 있다. (중략)

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.377-377
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• 2006

Alkoxyamine and thiocarbonyl thio end capped polyethylene (PE) chains were synthesized using a direct and simple approach consisting in reacting di(polyethylenyl)magnesium (PE-Mg-PE) chains with a range of nitroxides and disulfides of thiocarbonyl thio compounds. PE-Mg-PE compounds were prepared by a catalyzed chain growth reaction of ethylene on nbutyloctylmagnesium (BOMg) with a neodymocene complex $(C_{5}Me_{5})_{2}NdCl_{2}Li(OEt_{2})_{2}$. Complete characterizations confirm the introduction of the desired end groups. The controlled radical polymerization (NMP and RAFT) of butyl acrylate mediated by these functional polyethylenes was successful.

• 한국농공학회지
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• 제40권1호
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• pp.43-48
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• 1998

In order to provide basic information for the estimation of evapotranspiration for grass (Joycia Japonica), both field lysimeter experiment and model prediction were performed to estimate daily ET Various methods were used to predict daily reference crop ET and crop coefficients. Measured mean daily ET during the 1997 growing season was 4.5mm Model predicted mean daily ET during the 1997 growing season varied from 3.6 to 4.7mm depending on the prediction model Crop coefficients varied from 0.96 to 1.27 depending on the prediction model Comparison of the seven reference crop ET prediction methods used in this study shows that the Penman-Monteith method gave the smallest ET while the Hargreaves method gave the largest ET. The crop coefficient by the corrected Penman method was 1.03, which is closest to 1.0, suggesting that this method may he the best prediction method.

• Bulletin of the Korean Chemical Society
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• 제18권7호
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• pp.749-754
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• 1997

Rate constants have been measured spectrophotometrically for the reactions of alkali metal ethoxides (EtOM) with S-p-nitrophenyl 2-thiofuroate (1b) and 2-thiophenethiocarboxylate (2b) in absolute ethanol at 25.0±0.1 ℃. 1b is observed to be more reactive than 2b toward all the EtOM studied. The reactivity of EtOM is in the order EtOK > EtONa > EtO- > EtOLi for both substrates, indicating that K+ and Na+ behave as a catalyst while Li+ acts as an inhibitor in the present system. Equilibrium association constants of alkali metal ions with the transition state (KaTS) have been calculated from the known equilibrium association constants of alkali metal ion with ethoxide ion (Ka) and the rate constants for the reactions of EtOM with 1b and 2b. The catalytic effect (KaTS/Ka) is larger for the reaction of 1b than 2b, and decreases with decreasing the size of the alkali metal ions. Formation of 5-membered chelation at the transition state appears to be responsible for the catalytic effect.

• Bulletin of the Korean Chemical Society
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• 제15권8호
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• pp.654-658
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• 1994

Rate constants have been measured spectrophotometrically for the nucleophilic substitution reactions of p-and m-nitrophenyl 2-furoates (4 and 5, respectively) with alkali metal ethoxides ($EtO^-M^+$) in absolute ethanol at 25$^{\circ}$C. The reactivity of $EtO^-M^+$ toward 4 is in the order $EtO^-K^+$ > $EtO^-Na^+$> $EtO^-Li^+$ > $EtO^-K^+$+ 18-crown-6 ether. This is further confirmed by an ion pairing treatment method. The present result indicates that (1) ion paired $EtO^-M^+$ is more reactive than dissociated $EtO^-$ ; (2) the alkali metal ions ($K^+,\;Na^+,\;Li^+$) behave as a catalyst; (3) the catalytic effect increases with increasing the size of the metal ion. A similar result has been obtained for the reaction of 5, however, the catalytic effects shown by the metal ions are more significant in the reaction of 5 than in that of 4.

• Tuberculosis and Respiratory Diseases
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• 제44권4호
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• pp.844-852
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• 1997

연구배경 : 최근의 기관지천식 병인과 관련한 여러 연구에서 천식 발작중에 폐장에서 과도하게 유리된 endothelin(ET)이 기관지 수축을 유발시키는 주요한 펩티드임이 확인되었다. 이 연구의 목적은 급성발작의 경과에 따른 혈장 몇 요중치의 변동 및 상호 연관성을 관찰함에 있다. 방 법 : 연구대상은 16명의 급성 천식악화로 입원한 환자에서 내원당일과 치료 2주후의 2회의 혈장 및 24시간 요를 채취하였다. 정상대조군은 신체건강한 성인 10명으로 정하였다. 모든 천식환자는 입원당시 부신피질호르몬제, 베타-2 교감신경작동제, 아미노필린 제제를 투약받았다. ET은 방사면역측정법에 외해 측정되었으며 교차반응성에 있어 ET-1과는 100%, ET-2와 67%, ET-3와 84%, Big-ET과 8% 이었다. 결 과 : 혈장 ET은 천식환자의 및대조군의 수치와 비교하여 천식악화시 유의하게 증가하였다. 그러나 요중 ET은 천식악화시 및 치료후에 유의한 감소가 관찰되지 않았으나 정상대조군에 비해서는 둘다 유의하게 증가되어 있었다. 혈중 및 요중 ET치는 폐기능 및 저산소혈증 등과 유의한 상관관계는 없었다. 결 론 : 천식의 급성악화시에 증가한 혈장의 ET은 폐장에서의 ET 유리의 증가에 기인한 것으로 사료된다. 천식발작 환자는 정상인에 비해 요중 ET의 배설이 증가하여 있었으나 치료 2주후까지는 유의한 감소가 관찰되지 않았다. 따라서 천식발작시의 요중 ET의 변동을 관찰하기 위해서는 좀더 긴 관찰기간 및 많은 환자를 대상으로 포괄적인 연구가 되어야 할 것으로 생각된다.

• International Journal of Costume and Fashion
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• 제6권1호
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• pp.30-47
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• 2006

La $d\'{e}marche$ et l'objet de cette recherche sont d'analyser, psychiquement, $th\'{e}oriquement$, les marques de $l'intersexualit\'{e}$ $pr\'{e}sentent$ en Orient et les $\'{e}l\'{e}ments$ intersexuels, binaires dans le $v\hat{e}tement$, et $\'{e}galement$ de comprendre $l'ambiguit\'{e}$ ou encore la fusion des $identit\'{e}s$ $sexu\'{e}es$, qui $pr\'{e}sente$ symboliquement a travers le $v\hat{e}tement$, dans la $soci\'{e}t\'{e}$ moderne. La base fondamentale dans la $th\'{e}orie$ de l'Orient est que l'univers se divise en Yin ($caract\`{e}re\;f\'{e}minin$) et Yang ($caract\`{e}re$ masculin) et que tout individu $poss\`{e}de$ $\'{e}galement$ ce couple, en quelque sorte un intersexuel qui s'ignore, avec des variations selon l'individu. En $d\'{e}finitive$, les compositions doubles des $\'{e}l\'{e}ments$ dans le $v\hat{e}tement$ oriental montraient $embl\'{e}matiquement$ nos $qualit\'{e}s$ doubles, masculins et $f\'{e}minins$, et les trois $\'{e}l\'{e}ments$ semblent primordiaux pour $l'\'{e}lucidation$ de la $pr\'{e}disposition$ du porteur : la couleur du tissu, sa forme et la texture du $v\hat{e}tement$. La mode d'auiourd'hui oscille entre masculin et $f\hat{e}minin$. Cette fusion de la mode semble le reflet d'une tendance intersexuelle et d'une fusion du genre. Ainsi, cette recherche est, $\grave{a}$ travers $l'\'{e}l\'{e}ment$ masculin ou $f\'{e}minin$ des $v\hat{e}tements$, pour tenter de discerner lesprit, l'intention et le $caract\`{e}re$ sexuel dominant du porteur.