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Finite Element Analysis on Buckling Pressure by the Lamination of Composite Pressure Bull (복합재 내압선체의 적층에 따른 좌굴하중 변화에 관한 유한요소 해석)

  • Son J. Y.;Cho J. R.;Bae W. B.;Kwon J. H.;Choi J. H.;Cho Y. S.;Kim T. K.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.05a
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    • pp.458-462
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    • 2005
  • This paper deal with the optimal lamination condition of cylindrical shell applied new composite URN300 for a study of composite empirical formula. Finite element analyses for isotropic materials considered element numbers and boundary conditions are compared with existing empirical formulas to apply FE analysis for composite. And composite tensile test is done to know the composite material applied FE analysis for composite. The results of FE analyses for isotropic materials have indicated that Optimal element number and boundary condition were 1600 and both simple support. These conditions were applied in composite FE analyses. Ply orientations and lamination patterns in FE analyses for composite were considered. Ply orientations are $0^{\circ},\;15^{\circ},\;30^{\circ},\;45^{\circ},\;60^{\circ},\;75^{\circ},\;and\;90^{\circ}$. Lamination patterns are $[\pm\theta/0/90]_{14s]$ and $[\pm\theta_{14}/0_{14}/90_{14}]_s$ in FE analysis. Lamination pattern $[\pm\theta_{14}/0_{14}/90_{14}]_s$ is the equivalent model of $[\pm\theta/0/90]_{14s}$. At the result of this study, the FE analyses for composite have indicated that the optimized ply orientation $75^{\circ}$ is and real model must use in FE analysis for accurate results.

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Physicochemical characteristics of Sengmaksan added with Liriope platyphylla roasted for different times (덖음 처리 시간을 달리한 맥문동을 첨가한 생맥산의 이화학적 특성)

  • Kim, Gyeong-Wha;Kang, Min-Jung;Kang, Jae-Ran;Shin, Jung-Hye
    • Food Science and Preservation
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    • v.25 no.1
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    • pp.62-70
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    • 2018
  • This study investigates, the physicochemical characteristics of Sengmaksan (SM) prepared with Liriope platyphylla (LP) that had been roasted for different times (0, 30, 60, and 90 min, denoted as S-0, S-30, S-60, and S-90, respectively) The Hunter's color values such as lightness (L), redness (a), and yellowness (b) were the highest in S-0, while the lowest was found in S-90. The amount of soluble solid and reducing sugar content of S-60 were higher than the others. None of the samples exhibit significant differences in, their pH and acidity. The total content of phenolic compounds increased with the LP roasting time, but the total flavonoid and total anthocyanin contents of the SM decreased at the same time. The total ginsenoside (Ro, Rb2, Re, Rf, Rg1, Rg2, Rg3, Rh1, and Rh2) content did not show significant differences. The DPPH and ABTS radical scavenging activities increased according to the concentration, as well as with the LP roasting time. The ferric reducing antioxidant power (FRAP) showed trends similar to the radical scavenging activity, but it was more sensitive to the LP roasting time. From these results, the active ingredient in S-60 was higher, and the antioxidant activities of SM increased along with the roasting time of LP.

Identification of Amino Acids Involved in the Sensory Function of the PrrB Histidine Kinase by Site-directed Mutagenesis (Site-directed mutagenesis에 의한 PrrB histidine kinase의 신호인지 기능에 관련된 아미노산의 발굴)

  • Kim Yong-Jin;Ko In-Jeong;Oh Jeong-Il
    • Journal of Life Science
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    • v.16 no.3 s.76
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    • pp.485-492
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    • 2006
  • The PrrBA two-component system is one of the major regulatory systems that control expression of photosynthesis genes in response to changes in oxygen tension in the anoxygenic photosynthetic bacterium, Rhodobacter sphaeroides. The system consists of the PrrB histidine kinase and the PrrA response regulator. The N-terminal transmembrane domain of PrrB serves as a signal-sensing domain and comprises six transmembrane helices forming three periplasmic loops and two cytoplasmic loops. The $3^{rd}$ and $4^{th}$ transmembrane helices and the $2^{nd}$ periplasmic loop were suggested to play a crucial role in redox-sensory function. In this study we demonstrated that mutations of Asp-90, Gln-93, Leu-94, Leu-98, and Asn-106 in the $2^{nd}$ periplasmic loop and its neighboring region led to severe defects in PrrB sensory function, indicating that these amino acids might be related to the redox-sensing function of PrrB. The mutant forms (D90E, D90N, and D90A) of PrrB were heterologously overexpressed in Escherichia coli, purified by means of affinity chromatography and their autokinase activities were comparatively assessed. The D90N form of PrrB was shown to possess higher autokinase activity than the wild-type form of PrrB, whereas the D90E form of PrrB displayed lower autokinase activity than the wild-type form of PrrB. The D90A mutation led to the loss of PrrB autokinase activity.

The Effect of Deuterium Injection to Amorphous $Fe_{90}Zr_{10}$ (비정질 $Fe_{90}Zr_{10}$의 중수소 주입효과)

  • Park, C.M.;Kang, S.K.;Lee, K.B.;Kim, C.K.;Nahm, K.;Chang, K.H.;Kim, Y.B.;Kim, C.S.
    • Journal of the Korean Magnetics Society
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    • v.2 no.1
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    • pp.1-7
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    • 1992
  • Deuterium was injected into melt-spun ribbons of ${\alpha}-Fe_{90}Zr_{10}$ using the electrolytic hydrogenation method, and the magnetic properties of these ${\alpha}-D_{x}Fe_{90}Zr_{10}$ ribbons were studied. By comparing these results with those of ${\alpha}-H_{x}Fe_{91}Zr_{9}$, the effects of phonons to magnetic properties were investigated. The Curie temperature $T_{c}$, and the spontaneous magnetizations of the $D_{47}Fe_{90}Zr_{10}$ and the $Fe_{90}Zr_{10}$ were studied using the Mbssbauer spectroscopy. From these investigations, it was found that the Curie temperature of $D_{x}Fe_{90}Zr_{10}$ was 75K higher than that of $Fe_{90}Zr_{10}$. It was believed that this indicated the importance of local deformation to the amorphous magnetism. Also by comparing the spontaneous magnetizations of $D_{47}Fe_{90}Zr_{10}$ with those of $Fe_{90}Zr_{10}$ as a function of temperature, it was found that the deuterium injection reduced the fluctuation of exchange integral.

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Theoretical Study on the Geometric Property of Higher Fullerene C90 (Higher Fullerene C90의 기하학적 성질에 대한 이론적 연구)

  • Kwak, K.D.;Ha, Y.S.;Seo, M.R.
    • Applied Chemistry for Engineering
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    • v.10 no.6
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    • pp.881-884
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    • 1999
  • We have studied the other unit which is partial element in fullerene $C_{90}$. The energy of the higher fullerene increased by 5.6 kcal/mol for each $1.0{\beta}$ of planarity for the other units and increased by 11.0 kcal/mol for each $2C_1$ other unit at RHF/AM1 method. Therefore, we have known that the stable $C_{90}$ isomer do not have $C_1$ unit in other unit and have small planarity. The confirmable $C_{90}$ isomers by experiment satisfies these two conditions.

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Design of Composite Laminate Bicycle Wheel considering Stacking Sequence (적층각을 고려한 복합재료 라미네이트 자전거 휠의 설계)

  • Lee, Jin-Ah;Hong, Hyoung-Taek;Kang, Kyoung-Tak;Chun, Heoung-Jae
    • Composites Research
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    • v.25 no.5
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    • pp.141-146
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    • 2012
  • The strength design for the lightweight bicycle wheel made of the Carbon/Epoxy composite laminates has been discussed in this paper. For bicycle wheel design, lightness of the wheel is important. Also, it has to satisfy the required strength under specific loading cases. Two testing methods for the bicycle wheel, i.e. vertical and complex loadings, are adopted in this study. Because the strengths of composite wheel is different in relation to the stacking sequence and the number of plies, it is important to decide an appropriate stacking sequence and number of layers for the composite wheel. From the finite element analysis results, the most stable sequence orientation and number of layers are determined. The stacking sequence $[0]_{8n}$, $[90]_{8n}$, $[0/90]_{2ns}$, $[{\pm}45]_{2ns}$, $[0/{\pm}45/90]_{ns}$ (n=1,2,3,4)are performed for finite element analysis. From results, $[0/{\pm}45/90]_{3s}$ lay-up is a good selection for the composite bicycle wheel. Also, the weakest point and layer are found in this study.