• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.857-863
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• 1994

The absorption and fluorescence spectroscopic studies on the interaction between thionine (TH) and sodium dodecyl sulfate (SDS) have been carried out. The absorption and fluorescence spectral changes of TH with the changes of concentration of SDS are interpreted in terms of i) the aggregation of TH-SDS complex, ii) the stacking process of dye molecules by the association of the TH-SDS complex, iii) breakdown of the stacking due to the formation of dye-rich induced micelles, iv) redistribution of dye molecules in the surface of SDS micelles.

• Advances in aircraft and spacecraft science
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• v.10 no.4
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• pp.335-346
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• 2023

In this study, The Von Mises stresses in composite plate loaded in tension and repaired by a boron/epoxy scarf patch were analyzed using the finite element method. The performance of the repairs depends on several parameters: the dimensions and the intrinsic properties of the patch and the adhesive which are dependent on each other. Therefore, the method of experiment designs is used to determine the interaction effect of different parameters (patch folds), their optimum and the most influential parameter. The optimum of stacking sequences allows reducing stresses significantly, and thus permits designers to improve the quality of repairs.

• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.286-289
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• 1991

The changed isotropic absolute Raman intensities of the phosphate residue in the complexes of positive charge oligopeptides, lys-lys, arg-arg, lys-aromat-lys, negative charge diethyl phosphoric acid (DEP) and polyriboadenylic acid{poly(rA)} were reported and discussed. Our measurements showed that the absolute intensities of phosphate stretch vibration in complexes were different according to the reaction partners. Due to the partial electrical charge and molecular structure of oligopeptides for the complex formation lysine can interact more strongly than arginine when the reaction partners have short chain and no steric hindrance. Owing to these reasons the intensity of phosphate stretching vibration is very sensitive according to the circumstance of reaction. From our results we could suggest that we can discriminate any one of the the lysine and arginine in the complicated biological molecule during interaction between nucleotides and proteins. The activity of reaction of two basical oligopeptides is not quite similar for complex formation in aqueous solution. The activity of dipeptides depends upon the structure of molecule and environment for complex formation. Aromatic ring contributes to electrostatic interaction in complexes. The amount of the absolute intensity for pure stacking interaction is smaller than electrostatic interaction in macromolecular complexes.

• Steel and Composite Structures
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• v.25 no.1
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• pp.105-116
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• 2017

This paper presents the dynamic stability study of laminated composite plates with different force combinations and aspect ratios. Optimum non-diverging stacking is obtained for certain loading combination and aspect ratio. In addition, the stability force is maximized for a definite operating frequency. A dynamic version of the principle of virtual work for laminated composites is used to obtain force-frequency relation. Since dynamic stiffness governs the divergence or flutter, an efficient optimization method is necessary for the response functional and the relevant constraints. In this way, a model based on the ant colony optimization (ACO) algorithm is proposed to search for the proper stacking. The ACO algorithm is used since it treats with large number of dynamic stability parameters. Governing equations are formulated using classic laminate theory (CLT) and von-Karman plate technique. Load-frequency relations are explicitly obtained for fundamental and secondary flutter modes of simply supported composite plate with arbitrary aspect ratio, stacking and boundary load, which are used in optimization process. Obtained results are compared with the finite element method results for validity and accuracy convince. Results revealed that the optimum stacking with stable dynamic response and maximum critical load is in angle-ply mode with almost near-unidirectional fiber orientations for fundamental flutter mode. In addition, short plates behave better than long plates in combined axial-shear load case regarding stable oscillation. The interaction of uniaxial and shear forces intensifies the instability in long plates than short ones which needs low-angle layup orientations to provide required dynamic stiffness. However, a combination of angle-ply and cross-ply stacking with a near-square aspect ratio is appropriate for the composite plate regarding secondary flutter mode.

• Journal of the Korean Chemical Society
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• v.39 no.8
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• pp.604-610
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• 1995

The interaction between 3,3'-dipropyl oxacarbocyanine and poly(styrenesulfonate) has been studied by means of absorption and fluorescence spectroscopic methods. The results was interpreted by stacking model. The kinetic studies of the interaction between 3,3'-dipropyl oxacarbocyanine and poly(styrenesulfonate) were carried out by the absorption and fluorescence spectroscopic stopped-flow methods. The observed relaxation effect in DPC-PSS system was described quantitatively by assuming two relaxation processes. The dependence of rate of reaction on the salt concentration of the solution was also studied. The results are consistent with the two-step mechanism.

• Bulletin of the Korean Chemical Society
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• v.10 no.3
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• pp.254-258
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• 1989

Adsorption of 1,3-propanedithiol, 1,4-butanedithiol, 1,5-pentanedithiol, and 1,6-hexanedithiol on silver surface has been investigated by surface-enhanced Raman spectroscopy. It has been found that the conformations of the adsorbates were mainly affected by steric interaction of the adsorbates with the surface. As the alkyl chain length separating the thiol groups increased, surface stacking efficiency became increasingly important in determining conformation of the adsorbate on the surface.

• Archives of Pharmacal Research
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• v.4 no.2
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• pp.75-84
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• 1981

As the cetyltrimenthy ammonium bromide (CTAB) concentration increases to $2{\times}10^{-4}$/M the absorption maximum of ethyl orange (EO) makes a blue shift from 475 mm to 395 mm. At higher concentration of CTAB than $2{\times}10^{-4}$ / M the absorption maximum shifts to higher wavelength than 395 nm. A new peak at 395 nm is shown to result from the mixed micelle due to dye stacking interaction rather than from a change in dye geometry. Because Raman spectra of EO on interaction with varying amount of CTAB are similar to that of EO in water. EO retains trans azo type on interaction with CTAB. There is a change of c.m.c.s. of CTAB for the mixed micelle in the presence of salt. The effect of added salt on C. M. C. of CTAB for the mixed micelle is given that the logarithm of the c. m. c. is a linear function of the logarithm of the sum of the c. m. c. and the concentration of added salt.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.41.1-41.1
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• 2011

풍력블레이드는 가벼워야 하며 강도면에서 신뢰성이 확보되어야한다. 최근 들어 복합소재를 적용한 블레이드가 많이 선보이고 있다. 현재 가장 많이 사용되는 유리섬유/에폭시는 경제성 및 강도면에서 우수하여 많이 사용되어왔다. 본 논문에서는 유리섬유(80%)-탄소섬유(20%)/에폭시를 사용하여 강도를 높이고 무게를 경감시켜 효율을 증가시키고자 연구하였다. 국내 풍황에 적합한 1kW급 풍력블레이드의 Airfoil을 개발하여 강도를 평가하고 블레이드를 최적화 설계하였다. 유리섬유(80%)-탄소섬유(20%)가 적용된 복합재를 적층방법에 따라 실험하고 이를 블레이드 강도평가에 적용하였으며 FSI (Fluid-Structure Interaction)를 사용하였다. 이를 통해 블레이드의 무게경감 및 강도가 향상되었다.

• Bulletin of the Korean Chemical Society
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• v.18 no.5
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• pp.510-514
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• 1997

We studied the interaction of 4',6-diamidino-2-phenylindole (DAPI) with single stranded poly(dA) using optical spectroscopic methods, including absorption, circular dichroism (CD), and fluorescence spectroscopy. The temperature-dependent conformation of poly(dA) was also investigated. The conformation of poly(dA) varied with temperature, which is explained by the stacking-destacking process of the adenine bases, resulting from the sugar conformation. The hypochromicity and red-shift in the absorption spectroscopy, the lack of CD change in the drag absorption region, and the fluorescence behavior, especially a great accessibility of the I2 quencher to the poly(dA)-bound DAPI, suggest that DAPI binds to the outside of poly(dA). The Job plot for the DAPI-poly(dA) mixture demonstrated that a stoichiometry of one DAPI molecule binds to the one phosphate of poly(dA).

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.154-160
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• 1997

The interaction between pyronine G(PG) and surfactants has been examined by the absorption and fluorescence spectroscopy. The optimum condition for ${\gamma}$-band in PG-AOT system was found when S/D(concentration of surfactant / concentration of PG) was in the vicinity of 80. The disassociation of stacking conformation occured gradually at S/D>80. In PG-cationic and nonionic surfactant systems the absorptivity of monomeric PG increased. With the increment of the concentration of NaCl in PG-AOT system, the absorptivity of ${\gamma}$-band decreased at S/D<10 but, increased remarkably at S/D>20. PG-AOT system with the addition of NaCl showed greater dissociation than that without the addition of NaCl.