• Advances in materials Research
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• v.3 no.2
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• pp.117-128
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• 2014

Processable conducting polyaniline derivative with free amine functional groups was successfully synthesized from the monomer o-phenylenediamine in aqueous hydrochloric acid medium using ammonium persulfate as an oxidative initiator. The synthesized poly(o-phenylenediamine) (PoPD) in critical condition was found to be completely soluble in common organic solvents like dimethyl sulfoxide, N,N-dimethyl formamide etc. From the intrinsic viscosity measurement, the optimum condition for the polymerization was established. The polymer was characterized by ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, proton magnetic resonance spectroscopy ($^1HNMR$) and thermogravimetric (TGA) analyses. The weight average molecular weights of the synthesized polymers were determined by the dynamic light scattering (DLS) method. From the spectroscopic analysis the structure was found to resemble that of polyaniline derivative with free amine functional groups attached to ortho/meta position in the phenyl ring. However, very little ladder unit was also present with in the polymer chain. The moderate thermal stability of the synthesized polymer could be found from the TGA analysis. The average DC conductivity of $2.8{\times}10^{-4}S/cm$ was observed for the synthesized polymer pellet after doping with hydrochloric acid.

• Journal of applied mathematics & informatics
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• v.26 no.5_6
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• pp.1101-1121
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• 2008

One proposes an approach to fractional Fourier's transform, or Fourier's transform of fractional order, which applies to functions which are fractional differentiable but are not necessarily differentiable, in such a manner that they cannot be analyzed by using the so-called Caputo-Djrbashian fractional derivative. Firstly, as a preliminary, one defines fractional sine and cosine functions, therefore one obtains Fourier's series of fractional order. Then one defines the fractional Fourier's transform. The main properties of this fractal transformation are exhibited, the Parseval equation is obtained as well as the fractional Fourier inversion theorem. The prospect of application for this new tool is the spectral density analysis of signals, in signal processing, and the analysis of some partial differential equations of fractional order.

• Geomechanics and Engineering
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• v.21 no.1
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• pp.85-93
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• 2020

In this article, the generalized thermoelastic theory with fractional derivative is presented to estimate the variation of temperature, the components of stress, the components of displacement and the changes in volume fraction field in two-dimensional porous media. Easily, the exact solutions in the Laplace domain are obtained. By using Laplace and Fourier transformations with the eigenvalues method, the physical quantities are obtained analytically. The numerical results for all the physical quantities considered are implemented and presented graphically. The results display that the present model with the fractional derivative is reduced to the Lord and Shulman (LS) and the classical dynamical coupled (CT) theories when the fractional parameter is equivalent to one and the delay time is equal to zero and respectively.

• The Pure and Applied Mathematics
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• v.13 no.4 s.34
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• pp.261-267
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• 2006

A local convergence analysis of Newton's method for perturbed generalized equations is provided in a Banach space setting. Using center Lipschitzian conditions which are actually needed instead of Lipschitzian hypotheses on the $Fr\'{e}chet$-derivative of the operator involved and more precise estimates under less computational cost we provide a finer convergence analysis of Newton's method than before [5]-[7].

• Archives of Pharmacal Research
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• v.29 no.11
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• pp.942-945
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• 2006

A novel quinone derivative, Griseusin C (1), along with a known quinone, Naphthoquinone C (2), was isolated from the lyophilized culture broth of the marine-derived fungus Penicillium sp. The structures were elucidated on the basis of extensive 1D-and 2D-NMR, as well as HRESIMS, spectroscopic analysis. The relative stereochemistries of the compounds were assessed by NOESY analysis.

• Journal of the Korean earth science society
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• v.36 no.5
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• pp.437-446
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• 2015

Many edge detection methods, based on horizontal and vertical derivatives, have been introduced to provide us with intuitive information about the horizontal distribution of a subsurface anomalous body. Understanding the characteristics of each edge detection method is important for selecting an optimized method. In order to compare the characteristics of the individual methods, this study applied each method to synthetic magnetic data created using homogeneous prisms with different sizes, the numbers of bodies, and spacings between them. Seven edge detection methods were comprehensively and quantitatively analyzed: the total horizontal derivative (HD), the vertical derivative (VD), the 3D analytic signal (AS), the title derivative (TD), the theta map (TM), the horizontal derivative of tilt angle (HTD), and the normalized total horizontal derivative (NHD). HD and VD showed average good performance for a single-body model, but failed to detect multiple bodies. AS traced the edge for a single-body model comparatively well, but it was unable to detect an angulated corner and multiple bodies at the same time. TD and TM performed well in delineating the edges of shallower and larger bodies, but they showed relatively poor performance for deeper and smaller bodies. In contrast, they had a significant advantage in detecting the edges of multiple bodies. HTD showed poor performance in tracing close bodies since it was sensitive to an interference effect. NHD showed great performance under an appropriate window.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.583-590
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• 2002

Point collocation method based on the fast derivatives approximation of meshfree shape function is applied to solid mechanics in this study. Enhanced meshfree approximation with approximated derivative of shape function is reviewed, and formulation of linear elastic solid mechanics by point collocation method is presented. It implies that governing equation of solid mechanics with strong form is directly formulated without no numerical integration cells or grid. The regularity of weight function is not required due to a use of approximated derivative, so we propose the exponential type weight function that is discontinuous in first derivative. The convergence and stability of the proposed method is verified by passing the generalized patch test. Also, the efficiency and applicability of the proposed method in solid mechanics is verified by solving types of solid problems. Numerical results show that not only a use of proposed weight function leads lower error and higher convergence rate than that of the conventional weight functions, but also the improved collocation method with derivative approximation enables to compute the derivatives of shape function very fast and accurately enough to replace the classical direct derivative calculation.

• Journal of Advanced Research in Ocean Engineering
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• v.4 no.1
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• pp.35-46
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• 2018

In this paper, safety analysis of the process of installing offshore structures such as manifolds and jacket-type substructures using floating cranes and barges in waves is performed. The safety analysis consists of three components. First, the dynamic responses of the offshore structure, cranes, and barge, all of which are moored and connected using wire ropes, are analyzed. Second, tensions in the wire ropes connecting the cranes and the offshore structures are calculated. Finally, any collision between the offshore structure and the cranes or the barge that transports the offshore structure is detected. Equations of motion of the offshore structure, cranes, and barge are formulated based on multibody dynamics, as well as considering the hydrostatic, hydrodynamic, and mooring forces. Additionally, proportional-derivative control of the tagline between the cranes and the offshore structure is performed to verify the safety of the installation process, as well as for reducing the dynamic response and collisions among them.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.79-82
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• 1998

Film characteristics of thin ONO dielectric layers for MONOS(metal-oxide-nitride-oxide-semiconductor) EEPRM was investigated by AES and AFM. Second derivative spectra of AES Si LVV overlapping peak provided useful information for chemical state analysis of superthin film. The ONO films with dimension of tunneling oxide 24${\AA}$, nitride 33${\AA}$, and blocking oxide 40${\AA}$ were fabricated. During deposition of the LPCVD nitride films on tunneling oxide, this thin oxide was nitrized. When the blocking oxide were deposited on the nitride film, the oxygen not only oxidized the nitride surface, but diffused through the nitride. The results of ONO film analysis exhibits that it is made up of SiO$_2$(blocking oxide)/O-rich SiON(interface/N-rich SiON(nitride)/-rich SiON(interface)/N-rich SiON(nitride)/O-rich SiON(tunneling oxide).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.814-818
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• 2003

This paper deals with the application of numerical differentiation in free vibration analysis. In the free vibration analysis, the derivative values of the given function are certainly used in calculation of structural parameters. For deriving the derivative values, both the time and labor are needed when the structures consist of non-linear geometries such as arches or curved beams. From this viewpoint, the numerical differentiation scheme is applied into the free vibration analysis. The numerical results obtained from the numerical differentiations are agreed very well with those obtained from the exact derivatives by analytical method. It is expected that the numerical differentiations can be utilized practically in the free vibration analysis.