• Journal of the Korean Statistical Society
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• v.24 no.2
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• pp.537-549
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• 1995

In this article, we propose a class of weighted estimators for the excess risk in additive risk model with a binary covariate. The proposed estimator is consistent and asymptotically normal. When the assumed model is inappropriate, however, the estimators with different weights converge to nonidentical constants. This fact enables us to develop a goodness-of-fit test for the excess assumption by comparing estimators with diffrent weights. It is shown that the proposed test converges in distribution to normal with mean zero and is consistent under the model misspecifications. Furthermore, the finite-sample properties of the proposed test procedure are investigated and two examples using real data are presented.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.120-123
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• 2003

Immobilization behavior of methyl tert-butyl ether (MTBE) by various cyclodextrins(CDs) was studied to investigate the feasibility of MTBE removal using cyclodexrins. Even though MTBE has relatively low hydrophobicity and higher polarity compared to other organics, it was effectively immobilized by CDs. The immobilization isotherms was shown as a type of Freundlich isotherms, and the immobilization capacity of -CDs was the largest among natural COs. The initial apparent association constant for MTBE-CD complex follows the order : gamma = beta > methyl-beta > hydroxypropyl beta > alpha. These differences of the constants are related to the size of MTBE and CDs. The size of beta-CD and gamma-CD is large to encapsulate MTBE molecule into the cavity, which that of alpha-CB is too small to encapsulate MTBE.

• Advances in nano research
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• v.8 no.2
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• pp.169-182
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• 2020

This study presents the hygro-thermo-electromagnetic mechanical vibration attributes of elastically restrained piezoelectric nanobeam considering effects of beam surface for various elastic non-ideal boundary conditions. The nonlocal Eringen theory besides the surface effects containing surface stress, surface elasticity and surface density are employed to incorporate size-dependent effects in the whole of the model and the corresponding governing equations are derived using Hamilton principle. The natural frequencies are derived with the help of differential transformation method (DTM) as a semi-analytical-numerical method. Some validations are presented between differential transform method results and peer-reviewed literature to show the accuracy and the convergence of this method. Finally, the effects of spring constants, changing nonlocal parameter, imposed electric potential, temperature rise, magnetic potential and moisture concentration are explored. These results can be beneficial to design nanostructures in diverse environments.

• Journal of the Korean Society for Railway
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• v.3 no.2
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• pp.43-50
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• 2000

The corrugated panels are the prime candidate structure for the floor, roof and wall of Korean high speed train. The equivalent continuum modeling approach panels can be used for the efficient design and evaluation of their structural characteristics. The equivalent continuum models, derived from the true complex corrugated panels, should have the same structural behavior as the original structures have. This paper briefly reviews three representative continuum modeling methods: the static analysis method and two plate-models based on modal analysis methods (MAM). These methods are evaluated through some numerical examples by comparing the natural frequencies and static deflections. It is observed that the plate-model based on Rayleigh-Ritz method seems to provide the best results when used in conjunction with the cantilever-type boundary conditions. The equivalent elastic constants of various corrugated panels, depending on the changes in their configurations, are tabulated for efficient use in structural design.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.83-90
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• 2001

This paper resents an algorithm for the optimal parameter selection of a power system stabilizer in a single machine-infinite bus system through the external equivalent transmission line. This method is one of the classical techniques by changing the PSS gain to allocate properly pole-zero positions. All the PSS parameters are obtained by solving a set of algebraic equations for the system constants depend on a variety of machine loadings and system external impedances, the natural oscillation modes, and the damping characteristics. And this algorithm was written in a simple software program using MATLAB.

• Textile Coloration and Finishing
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• v.2 no.2
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• pp.33-38
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• 1990

Nitrocellulose [NC]-Poly(vinylamine) [PVAm] blended membranes with the change of amino group contents were prepared. The sorption and permeation of a mono-sulfonic acid dye, Orange II, in the membranes were investigated by the steady-state permeation method at $50^{\circ}C$ and pH 2.2. The results were discussed in the framework of dual sorption and diffusion theory. It was found that thesorption isotherms comprise a partition and two Langmuir type adsorption having similar binding constants. One of the latter sorption modes is due to unknown adsorption sites in NC and the other is due to the amino groups in PVAm. Apparent diffusion coefficients for collective P and L dye species, $D_P\; and D_L$, were obtained. Interpretation of $D_P$ values leads to two modes of partitions; one is such that dye is immobilized in NC and the other is the dissolution of the dye into the internal water phase.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.565-569
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• 2001

The spectral correction matrix has been established to study the simultaneous complextions between metals and a ligand, and it eliminated the mutual influence among the complexes. The two sensitive reations between iron(Ⅱ) and 1-(6-bromo-2-benzothiazolylazo)-2-naphthol(BBTAN) and zinc (Ⅱ) and BBTAN have been investigated and applied to the simultaneous determination of Zn and Fe at pH 8.5 in the presence of triton x-100. This method gave the simples determination of the characteristic constants of the complexes. For the analysis of natural water, foods and other samoles, the recoveries of Fe and Zn were between 92 and 109% and between 91 and 104%, and their relative standard deviations were less than 5.5 and 11%, respectively.

• Journal of Integrative Natural Science
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• v.7 no.1
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• pp.1-4
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• 2014

Distributed Bragg reflector porous silicon of different characteristics were formed to determine their optical constants in the visible wavelength range using a periodic square wave current between low and high current densities. The surface and cross-sectional SEM images of distributed Bragg reflector porous silicon were obtained using a cold field emission scanning electron microscope. The surface image of distributed Bragg reflector porous silicon indicates that the distributions of pores are even. The cross-sectional image illustrates that the multilayer of distributed Bragg reflector porous silicon exhibits a depth of few microns and applying of square current density during the etching process results two distinct refractive indices in the contrast. Distributed Bragg reflector porous silicon exhibited a porosity depth profile that related directly to the current-time profile used in etch. Its free-standing film was obtained by applying an electro-polishing current.

• Archives of Pharmacal Research
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• v.6 no.1
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• pp.63-68
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• 1983

The binding properties of three ginsenosides, Rb$_{1}$, Rc and Re, to bovine and human serum albumins have been examined by fluorescence probe technique. 1-anilinonphathalene-8-sulfonate (ANS) was used as the fluorescence probe. Protopanaxatriol glycoside, Re, did not quench the fluorscence of ANS to the bovine serum albumin. Competitive bindings between protopanaxadiol glycosides, Rb$_{1}$ and Rc are both 3.3 . The binding constants for Rb$_{1}$ and Rc with bovine serum albumin were 1.91 * 10$_{4}$M$_{-1}$ AND 1.04 * 10$^{[-994]}$ M$^{-1}$ , respectively. The ginsenosides, Rb$_{1}$, Rc and Re did not quench the fluorescence of ANS bound to human serum albumin.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.141-146
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• 2011

Loess, a natural clay, was evaluated as an adsorbent for the decolorization of Acid Orange II, an azo and reactive dye, from aqueous solution. Adsorption studies were performed at $30^{\circ}C$ and the effect of reaction time, loess dosage, initial concentration, loess particle size, pH, agitation rate were investigated to determine the optimum operation conditions. The removal efficiencies of color were measured to evaluate the effectiveness of loess. From this study, it was found that optimal reaction time was 10 min. Color removal efficiencies of Acid Orange II were increased as higher loess dosage, initial concentration and agitation rate. However, color removal efficiencies decreased when pH is high and loess particle becomes large. Adsorption of Acid Orange II fitted to the pseudo-second-order rate kinetics more than first-order rate kinetics. Langmuir and Freundlich adsorption isotherm constants and correlation coefficients were calculated and compared. It was concluded that the adsorption data of Acid Orange II onto loess fitted to the Freundlich model more than Langmuir model.