• Bulletin of the Korean Chemical Society
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• v.11 no.6
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• pp.497-505
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• 1990

The function exp$(x^2)$erfc(x), which is often encountered in studies of electrode kinetics, is evaluated to an extended precision with 32 significant decimal digits in order to find theoretical relationships used in derivative polarography/voltammetry for a chemically-coupled electrode process. Computations with a lower precision are not successful. Evaluation of the function is accomplished by using three types of expansions for the function. Best ranges of arguments are selected for each equation for particular precisions for efficiencies. The method is successfully applied to calculate higher-order derivatives of the current-potential curves in all potential ranges for a reversible electron transfer reaction coupled with a prior chemical equilibrium (i.e., a CE type process). Various parameters that characterize the peak asymmetry (such as ratios of peak-heights, ratios of half-peak-widths, and separations in peak-potentials) are analyzed to find how kinetic and thermodynamic parameters influence shapes of the derivatives. The results from the CE process is compared with those from an EC process in which a reversible electron transfer is coupled with a follow-up homogeneous chemical reaction. The two processes exibit quite contrasting differences for values of the parameters.

• Structural Engineering and Mechanics
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• v.10 no.4
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• pp.337-357
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• 2000

Analytical formulations and solutions for the first time, to the stability analysis of a simply supported composite and sandwich plates based on a higher order refined theory, developed by the first author and already reported in the literature are presented. The theoretical model presented herein incorporates laminate deformations which account for the effects of transverse shear deformation, transverse normal strain/stress and a nonlinear variation of inplane displacements with respect to the thickness coordinate - thus modelling the warping of transverse cross sections more accurately and eliminating the need for shear correction coefficients. The equations of equilibrium are obtained using the Principle of Minimum Potential Energy (PMPE). The comparison of the results using this higher order refined theory with the available elasticity solutions and the results computed independently using the first order and the other higher order theories developed by other investigators and available in the literature shows that this refined theory predicts the critical buckling load more accurately than all other theories considered in this paper. New results for sandwich laminates are also presented which may serve as a benchmark for future investigations.

• Journal of Ocean Engineering and Technology
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• v.15 no.1
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• pp.12-18
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• 2001

This study concentrates on the second-order diffraction problem around circular cylinders in multi-frequency waves. The method of solution is a time-domain Rankine panel method which adopts a higher-order approximation for the velocity potential and wave elevation. In the present study, the multiple second-order quadratic transfer functions are extracted from the second-order time signal generated in random waves, and the comparison with other bench-mark test results shows a good agreement. This approach is directly applicable to prediction of nonlinear forces on offshore structures in random ocean.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.3
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• pp.31-40
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• 2001

Low-order panel methods are being used to design marine propellers. Since the potential value over each panel for these methods is assumed to be a constant, the accuracy of prediction is known to be limited. Therefore, a higher order boundary element method(HOBEM) has been studied to enhance the accuracy of prediction. In this paper, a HOBEM representing the body boundary surfaces and physical quantities by a 9-node Lagrangian shape function is employed to analyse the flow around marine propellers in steady potential flow. First, the numerical results for a circular wing with thickness variations are compared with Jordan's linear solution. Then, the computational results of two propellers(DTRC 4119 & DTRC 4842 propeller) are compared with the experimental and numerical results published. The pressure distribution on the surface of the propeller is also compared with experimental data.

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.395-405
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• 1973

By use of an Integral Hellmann-Feynman formula, the cubic crystal field splitting 1O Dq in $KNiF_3$ is calculated from first principles. Numerical values of covalency parameters and necessary integrals are quoted from Sugano and Shulman. The result, 7100$cm^{-1}$, is in excellent agreement with the observed value, 7250$cm^{-1}$. It is found that higher order perturbation energy correction is of the same order of magnitude as 10 Dq itself and is, therefore, essential tin calculating 10 Dq from first principles. It is also found that the point charge potential is the dominant part of the crystal field potential.

• Ocean Systems Engineering
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• v.9 no.1
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• pp.97-109
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• 2019

Accurate calculation of the mean drift forces and moments is necessary when studying the higher order excitations on the floater in waves. When taking the time average of the second order forces and moments, the second order potential and motion diminish with only the first order terms remained. However, in the results of the first order forces or motions, the irregular frequency effects are often observed in higher frequencies, which will affect the accuracy of the calculation of the second order forces and moments. Therefore, we need to pay close attention to the irregular frequency effects in the mean drift forces. This paper will discuss about the irregular frequency effects in the calculations of the mean drift forces and validate our in-house program MDL Multi DYN using some examples which are known to have irregular frequency effects. Finally, we prove that it is necessary to remove the effects and demonstrate that the effectiveness of the formula and methods adopted in the development of our program.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.287-293
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• 2007

The researchers have studied for a long time about the depth of anesthesia but they don't make criteria for the depth of anesthesia. Anesthetists can't make a prediction about patient's reaction. Therefore, patients have potential risk such as poisonous side effect, late-awake, early-awake and strain reaction. In this study, the distributed characteristics on the bispectrum and bicoherence, the type of nonlinear signal processing, as a result of the coupling of EEG were presented according to depth of anesthesia. These results were consistent with a trend of delta ratio that the index of evaluation for the depth of anesthesia. The higher-order spectrum (HOS), the bispectrum and bicoherence, gives the useful information about depth of anaesthesia than other indexes.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.2
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• pp.57-69
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• 2000

A higher order panel method based on representation for both the geometry and the velocity potential is developed for the analysis of steady flow around marine propellers. The self-influence functions due to the normal dipole and the source are desingularized through the quadratic transformation, and then the singular part is integrated analytically whereas the non-singular part is integrated using Gaussian quadrature. A null pressure jump Kutta condition at the trailing edge is found to be effective in stabilizing the solution process and in predicting the correct solution. Numerical experiments indicate that the present method is robust and predicts the pressure distribution around lifting bodies with much fewer panels than existing low order panel methods.

• Journal of the Korean Chemical Society
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• v.21 no.1
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• pp.23-31
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• 1977

For the metal complex of $d^1$ configuration with the octahedrally coordinated ligands, the crystal field parameter, 10Dq, is calculated from first principles within the framework of the crystal field theory. With the point charge model, the configuration interaction is introduced by use of the Shull-L$\"{o}$wdin functions. Through the Integral Hellmann-Feynman Theorem, the higher order effect is visualized. It is found that the higher order effect on 10Dq is about $50{\%}$ of the first order effect. Since 3d function is angularly undistorted and radially equally distorted in $E_g\;and\;T_{2g}$ states, due to the octahedral potential, the calculated 10Dq is still the unique parameter for the splitting.

• Journal of Environmental Science International
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• v.12 no.6
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• pp.583-591
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• 2003

The research on potential energy was conducted to conserve the high-exergy energy like primary energy and utilize waste heat from sewage. From the Point of view in using the waste heat, the energy Potential of waste water from the model house was simulated. From the results, when the heated water was supplied to the model house side in order to put unused energy to Practice use, heated water had higher energy Potential than unheated water, which was due to the discharge of most of unused energy. The possessing heat capacity of sewage from heated water was increased to 40-70 percents in comparison with that from the unheated water. Therefore, it can be used as energy source for improving coefficient of performance of heat pumps. By adopting the multiple heat pump into a model house, It showed that the possessing heat capacity of sewage was reduced. It was also found that the heat was recovered as energy source fur multiple heat pump in a model house.