• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1731-1736
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• 2003

The reaction of ${\alpha}$-Benzilmonoxime with palladium(II) produces a green complex in triton X-100 micellar media. Palladium has been determined using zero and first derivative spectrophotometric methods. The absorbances of Pd(II)- ${\alpha}$--benzilmonoxime complex at 441.8 and 677.0 nm in 0.10 M perchloric acid solution were monitored and linear working ranges of 0.3-12.0 and 0.7-20 ${\mu}$g mL$^{-1}$ with detection limits of 0.07 and 0.10 ${\mu}$g $mL^-1$ were obtained, respectively. Also, recoveries in the range of 92.8 to 100.1% and relative standard deviations in the range of 0.4 to 7.1% were obtained. First derivative spectrophotometry has also been applied for palladium determination under the optimum condition. The linear dynamic range of 0.2-24.0 ${\mu}$g $mL^{-1}$ palladium with relative standard deviations of 0.6-6.9% and recoveries in the range of 94.9-102.5% has been obtained by first derivative spectrophotometry. The method shows high selectivity because of the high concentration of acid used, which prevents formation of complexes of ${\alpha}$--benzilmonoxime with the other cations. The palladium complex formed was stable at least one day. The method was successfully applied to the determination of palladium in some synthetic palladium alloys and palladium-charcoal powder.

• Korea-Australia Rheology Journal
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• v.19 no.4
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• pp.201-209
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• 2007

The present paper is concerned with non-isothermal spherical Couette flow of Oldroyd-B fluid in the annular region between two concentric spheres. The inner sphere rotates with a uniform angular velocity while the outer sphere is kept at rest. Moreover, the two spherical boundaries are maintained at fixed temperature values. Hence, the fluid is effect by two heat sources; namely, the viscous heating and the temperature gradient between the two spheres. The viscoelasticity of the fluid is assumed to dominate the inertia such that the latter can be neglected. An approximate analytical solution of the energy and momentum equations is obtained through the expansion of the dynamical fields in power series of Nahme number. The analysis show that, the temperature variation due to the external source appears in the zero order solution and its effect extends to the fluid velocity distribution up to present second order. Viscous heating contributes in the first and second order solutions. In contrast to isothermal case, a first order axial velocity and a second order stream function fields has been appeared. Moreover, at higher orders the temperature distribution depends on the gap width between the two spheres. Finally, there exist a thermal distribution of positive and negative values depend on their positions in the domain region between the two spheres.

• Journal of applied mathematics & informatics
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• v.26 no.5_6
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• pp.1057-1069
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• 2008

We consider singularly perturbed Boundary Value Problems (BVPs) for third and fourth order Ordinary Differential Equations(ODEs) of convection-diffusion type with discontinuous source term and a small positive parameter multiplying the highest derivative. Because of the type of Boundary Conditions(BCs) imposed on these equations these problems can be transformed into weakly coupled systems. In this system, the first equation does not have the small parameter but the second contains it. In this paper a computational method named as 'An asymptotic finite element method' for solving these systems is presented. In this method we first find an zero order asymptotic approximation to the solution and then the system is decoupled by replacing the first component of the solution by this approximation in the second equation. Then the second equation is independently solved by a fitted mesh Finite Element Method (FEM). Numerical experiments support our theoritical results.

• Wind and Structures
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• v.3 no.2
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• pp.117-132
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• 2000

Under special conditions of turbulent wind, suspension and cable-stayed bridges could reach instability conditions. In various instances the bridge deck, as like a bluff body, could exhibit single-degree torsional instability. In the present study the turbulent component of flow has been considered as a solution of a differential stochastic linear equation. The input process is represented by a Gaussian zero-mean white noise. In this paper the analytical solution of the dynamic response of the bridge has been determined. The solution has been obtained with a technique of closing on the order of the moments.

• Korean Journal of Optics and Photonics
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• v.9 no.5
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• pp.282-290
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• 1998

The equivalent lens conversion technique is applied to design achromatic doublet and aplanatic doublet. A thin doublet which has zero axial thicknesses, are corrected for the third order aberrations at first, and the thin doublet is converted into thick lens system by using the equivalent lens conversion. Two types of cemented doublets, the Fraunhofer type and the Steinheil type, are designed by using a crown glass BaK-2 and a flint glass SF-2. In the thin doublet design, there are two achromatic solutions and a aplanatic solution for the both types.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.355-360
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• 1995

In order to align the shaft, the dialgauge method has used as a means of solution until now. The method using a dialgauge require a great deal of labour and money due to making by hand, the accurate alignmentis not up to the expectation. For aligning the shaft, all the rotor must come to accord. It means that the moment of the point of coupling must keep being "Zero". The ideal measurement method as to material on the zero is used by straingauge which can gauge the moment at any point of the shaft. Also, the dialgauge method cannot be compared with straingauge measurement method, form the viewpoint, which can gauge in short time.hort time.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.104-107
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• 1999

Tracking control of an arbitrary reference has been discussed for 7Th order 2-input 2-output non-minimum phase EGR/VGT diesel engines. To meet strict emission regulations and customer demands, the desired set points, the air-fuel ratio and the ERG flow fraction, determined from a static engine data based on engine speed and the desired fueling rate are transformed into the set points for the two sensor measurement outputs. Applying the sliding mode tracking control theory proposed by Jeong and Utkin, two step design was carried out using the bounded solution of an unstable zero dynamics for the given reference signals. This paper shows through simulations how stabilization of unstable zero dynamics and reference tracking can be accomplished simultaneously.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.4
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• pp.427-432
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• 2001

The purpose of study is to examine the sensitivity of the rate of degradation to initial TCE concentration and iron concentration in the solution. The batch tests were executed to assess the degradation rate at varying initial conditions. First order rate constants($k_a$) were more rapid with the lower initial TCE concentration, Howere the correleation was not always linear between $k_a$ and initial TCE concentration. $k_a$ was proportionally increased as the increasing surface area. It implied that the effective reactive surface area acted as the limiting factor on the reductive dechlorination of TCE by iron.

• Bulletin of the Korean Mathematical Society
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• v.54 no.3
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• pp.993-1002
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• 2017

Let ${\Omega}$ be a bounded, uniformly totally pseudoconvex domain in ${\mathbb{C}}^2$ with the smooth boundary b${\Omega}$. Assuming that ${\Omega}$ satisfies the negative ${\bar{\partial}}$ property. Let M be a positive, finite area divisor of ${\Omega}$. In this paper, we will prove that: if ${\Omega}$ admits a maximal type F and the ${\check{C}}eck$ cohomology class of the second order vanishes in ${\Omega}$, there is a bounded holomorphic function in ${\Omega}$ such that its zero set is M. The proof is based on the method given by Shaw [27].

• Bulletin of the Korean Mathematical Society
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• v.53 no.1
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• pp.29-38
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• 2016

For a transcendental entire function f(z) with zero order, the purpose of this article is to study the value distributions of q-difference polynomial $f(qz)-a(f(z))^n$ and $f(q_1z)f(q_2z){\cdots}f(q_mz)-a(f(z))^n$. The property of entire solution of a certain q-difference equation is also considered.