• Journal of applied mathematics & informatics
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• v.29 no.3_4
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• pp.763-779
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• 2011

In this paper we apply the Exp-function method to obtain traveling wave solutions of three nonlinear partial differential equations, namely, generalized sinh-Gordon equation, generalized form of the famous sinh-Gordon equation, and double combined sinh-cosh-Gordon equation. These equations play a very important role in mathematical physics and engineering sciences. The Exp-Function method changes the problem from solving nonlinear partial differential equations to solving a ordinary differential equation. Mainly we try to present an application of Exp-function method taking to consideration rectifying a commonly occurring errors during some of recent works.

• Communications of the Korean Mathematical Society
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• v.19 no.2
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• pp.307-319
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• 2004

In this paper, we establish some new oscillation criteria for the functional differential equations of the form $\frac{d}{dt}$$\frac{1}{a_{n-1}(t)}$$\frac{d}{dt}(\frac{1}{{a_{n-2}(t)}\frac{d}{dt}(...(\frac{1}{a_1(t)}\frac{d}{dt}x(t))...)))^\alpha$ + $\delta[f_1(t,s[g_1(t)],\frac{d}{dt}x[h_1(t)])$ + $f_2(t,x[g_2(t)],\frac{d}{dt}x[h_2(t)])]=0$ via comparing it with some other functional differential equations whose oscillatory behavior is known.

• Journal of the Korean Mathematical Society
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• v.41 no.6
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• pp.1049-1070
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• 2004

We classify all partial differential equations with polynomial coefficients in $\chi$ and y of the form A($\chi$) $u_{{\chi}{\chi}}$ ＋ 2B($\chi$, y) $u_{{\chi}y}$ ＋ C(y) $u_{yy}$ ＋ D($\chi$) $u_{{\chi}}$ ＋ E(y) $u_{y}$ = λu, which has weak orthogonal polynomials as solutions and show that partial derivatives of all orders are orthogonal. Also, we construct orthogonal polynomials in d-variables satisfying second order partial differential equations in d-variables.s.

• Journal of Pharmaceutical Investigation
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• v.27 no.3
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• pp.233-239
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• 1997

Glibenclamide is a second generation sulfonylurea that is orally active as a hypoglycemic drug. It exists as a crystalline powder which is sparingly soluble in water. It was investigated that the potential of glibenclamide to exhibit polymorphism. Three polymorphic modifications (form 1, form 2 and form 3) and three pseudopolymorphic modifications (form 4, form 5 and form 6) were obtained by crystallization from different organic solvents. The isolated crystal forms were characterized by differential scanning calorimetry(DSC), thermogravimetric analysis(TGA) and X-ray crystallography powder diffraction studies. Form 1 was the most stable and melt at $175.4^{\circ}C$. Form 2 was metastable and melt at $151.0^{\circ}C$. Form 3 was a new polymorphic modification because it was different from form 1 and form 2 in X-ray crystallography powder diffraction data. Form 4 was a 1 : 7(toluene : glibenclamide) toluene solvate; form 5 was a 1 : 5(toluene : glibenclamide) toluene solvate; form 6 was a 3 : 8(pentanol : glibenclamide) pentanol solvate. All forms were stable in 3-month storage under 0% or 100% humidity condition. The dissolution rate of form 4 was highest; those of form 2, form 3, form 1, form 5 and form 6 followed.

• Structural Engineering and Mechanics
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• v.62 no.3
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• pp.345-355
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• 2017

The aim of the present study is to develop an elemental approach based on the differential quadrature method for free vibration analysis of cracked thin plate structures. For this purpose, the equations of motion are established using the classical plate theory. The well-known Generalized Differential Quadrature Method (GDQM) is utilized to discretize the governing equations on each computational subdomain or element. In this method, the differential terms of a quantity field at a specific computational point should be expressed in a series form of the related quantity at all other sampling points along the domain. However, the existence of any geometric discontinuity, such as a crack, in a computational domain causes some problems in the calculation of differential terms. In order to resolve this problem, the multi-block or elemental strategy is implemented to divide such geometry into several subdomains. By constructing the appropriate continuity conditions at each interface between adjacent elements and a crack tip, the whole discretized governing equations of the structure can be established. Therefore, the free vibration analysis of a cracked thin plate will be provided via the achieved eigenvalue problem. The obtained results show a good agreement in comparison with those found by finite element method.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.3
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• pp.176-182
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• 2021

This research proposes a high-frequency circuit that can accurately predict the differential mode noise of single-phase inverters at the circuit design stage. Proposed single-phase inverter high frequency circuit in the work is a form in which harmonic impedance components are added to the basic single-phase inverter circuit configuration. For accurate noise prediction, parasitic components present in each part of the differential noise path were extracted. Impedance was extracted using a network analyzer and Q3D in the measurement range of 150 kHz to 30 MHz. A high-frequency circuit model was completed by applying the measured values. Simulations and experiments were conducted to confirm the validity of the high-frequency circuit. As a result, we were able to predict the resonance point of the differential mode voltage extracted as an experimental value with a high-frequency circuit model within an approximately 10% error. Through this outcome, we could verify that differential mode noise can be accurately predicted using the proposed model of the high-frequency circuit without a separate test bench for noise measurement.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.3
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• pp.119-127
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• 2003

Impossible differential cryptanalysis(IDC) introduced by Biham et. ${al}^{[4]}$ uses impossible differential characteristics. There-fore, a security of a block cipher against IDC is measured by impossible differential characteristics. In this paper, we pro-vide a wildly applicable method to find various impossible differential characteristics of block cipher structures not using the specified form of a round function. Using this method, we can find various impossible differential characteristics for Nyberg's generalized Feistel network and a generalized RC6-like structure. Throughout the paper, we assume round functions used in block cipher structures are bijective.ctive.

• Journal of Pharmaceutical Investigation
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• v.32 no.2
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• pp.81-85
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• 2002

Three polymorphic modifications of CKD-602, water soluble derivative of camptothecin, were obtained by the recrystallization from different organic solvents and characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray powder diffraction (XRPD). The major endothermic peaks of the DSC curve of Form 1, Form 2 and Form 3 was shown at $268.71^{\circ}C$, $247.83^{\circ}C$, $244.76^{\circ}C$, respectively. Form 2 was elucidated to be an acetic acid solvate and Form 3 was elucidated to be a methanol solvate. The dissolution patterns of these three modifications were also checked in distilled water at $37{\pm}0.5^{\circ}C$, for 30 minutes. The polymorphic modifications showed differences in the dissolution rate. The dissolution rate of Form 1 was faster than that of other polymorphic modifications. When stored at different relative humidity over the period of 3 months, all of the polymorphic modifications did not undergo transformation.

• Communications of the Korean Mathematical Society
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• v.26 no.4
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• pp.695-708
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• 2011

Based on the multiple-time-scale (MTS) method, a general formula has been presented for solving an n-th, n = 2, 3, ${\ldots}$, order ordinary differential equation with strong linear damping forces. Like the solution of the unified Krylov-Bogoliubov-Mitropolskii (KBM) method or the general Struble's method, the new solution covers the un-damped, under-damped and over-damped cases. The solutions are identical to those obtained by the unified KBM method and the general Struble's method. The technique is a new form of the classical MTS method. The formulation as well as the determination of the solution from the derived formula is very simple. The method is illustrated by several examples. The general MTS solution reduces to its classical form when the real parts of eigen-values of the unperturbed equation vanish.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.45-50
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• 2005

This paper make an analysis of UWB Communication System. In case endoscope, medical equipment, is applied to UWB, We could study through body-channel that frequency transmitted of received signal is differ from wireless in the existing air. It suggested TR-UWB form, non-coherent received method in dispersion-medium like humans bodies by accomplishing ability analysis of BPM, TR, BER of Differential, UWB Communication modulation and demodulation form.