• Korean Journal of Soil Science and Fertilizer
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• v.6 no.4
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• pp.253-255
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• 1973

Microscopic method was compared with X-ray diflraction analysis for the identification of rockforming minerals using 11 main rock samples in Korea. 1. There was no difference between X-ray diffraction analysis and microscopic one in major minerals, but some accessary minerals. 2. The rock-forming minerals of main rocks presented in this study occured almost in crystalline state so that they could be easily identified by X-ray analysis alone.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.4
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• pp.415-425
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• 2003

A single particle analysis, called low-Z electron probe X-ray microanalysis was applied to characterize the atmospheric aerosols collected during Asian Dust storm events in the year of 2000 and 2001. Most frequently encountered chemical species were the soil-originated species such as aluminosilicates, silicon dioxide, and calcium carbonate. Also various species such as carbon -rich, organics, sea salts, and some reacted calcium carbonate were identified. The observation of internally mixed particles oi calcium carbonate, calcium nitrate and/or calcium sulfate shows the occurrence of the heterogeneous reaction between Asian Dust particles and NO$_{x}$ and/or SO$_{x}$ species in the atmosphere.ere.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.3
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• pp.315-323
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• 2003

The goal of this study if the optimization of discharge electrode for pulsed corona discharge reactor located in thermal power plant. For this purpose, we have performed experiments of NO$_{x}$ removal rate by exchange of discharge electrode diameter and arrangement of discharge electrode in the non -thermal plasma reaction facility using a ethylene as additive. If the diameter and numbers of discharge electrode were larger, the NO$_{x}$ removal rate was higher. From these results, if we optimized the shape and installed numbers of discharge electrode at the pilot plant, we could increase the NO$_{x}$ removal rate with less amount of additive than current amount.mount.

• Bulletin of the Korean Mathematical Society
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• v.51 no.6
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• pp.1615-1623
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• 2014

Let $G{\leq}S_n$ and ${\chi}$ be any nonzero complex valued function on G. We first study the irreducibility of the generalized matrix polynomial $d^G_{\chi}(X)$, where $X=(x_{ij})$ is an n-by-n matrix whose entries are $n^2$ commuting independent indeterminates over $\mathbb{C}$. In particular, we show that if $\mathcal{X}$ is an irreducible character of G, then $d^G_{\chi}(X)$ is an irreducible polynomial, where either $G=S_n$ or $G=A_n$ and $n{\neq}2$. We then give a necessary and sufficient condition for the equality of two generalized matrix functions on the set of the so-called ${\chi}$-singular (${\chi}$-nonsingular) matrices.

• Bulletin of the Korean Mathematical Society
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• v.43 no.3
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• pp.471-478
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• 2006

In this paper we prove that if AX=b is a partial sign-solvable linear system with A being sign non-singular matrix and if ${\alpha}=\{j:\;x_j\;is\;sign-determined\;by\; Ax=b\}, then $A_{\alpha}X_{\alpha}=b_{\alpha}$ is a sign-solvable linear system, where $A_{\alpha}$ denotes the submatrix of A occupying rows and columns in o and xo and be are subvectors of x and b whose components lie in ${\alpha}$. For a sign non-singular matrix A, let $A_l,\;...,A_{\kappa}$ be the fully indecomposable components of A and let ${\alpha}_i$ denote the set of row numbers of $A_r,\;r=1,\;...,\;k$. We also show that if $A_x=b$ is a partial sign-solvable linear system, then, for $r=1,\;...,\;k$, if one of the components of xor is a fixed zero solution of Ax=b, then so are all the components of x_{{\alpha}r}$.

• Journal of Korean Society for Quality Management
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• v.22 no.2
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• pp.89-97
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• 1994

We consider the linear calibration model: $y_1={\alpha}+{\beta}x_i+{\sigma}{\varepsilon}_i$, i = 1, ${\cdots}$, n, $y={\alpha}+{\beta}x+{\sigma}{\varepsilon}$ where ($y_1$, ${\cdots}$, $y_n$, y) stands for an observation vector, {$x_i$} fixed design vector, (${\alpha}$, ${\beta}$) vector of regression parameters, x unknown true value of interest and {${\varepsilon}_i$}, ${\varepsilon}$ are mutually uncorrelated measurement errors with zero mean and unit variance but otherwise unknown distributions. On the basis of simple small-sample low-noise approximation, we introduce a new method of comparing the mean squared errors of the various competing estimators of the true value x for finite sample size n. Then we show that a class of estimators including the classical and the inverse estimators are consistent and first-order efficient within the class of all regular consistent estimators irrespective of type of measurement errors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.1016-1020
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• 2000

In this study, a structural characteristics analysis system for motor-integrated high-speed spindle systems, “SpindleX”, is developed based on the Timoshenko theory and the multi-layered finite element method. Since “SpindleX” has the various analysis modules related to static deflection analysis, modal analysis, frequency response analysis, unbalance response analysis and so on, it is useful in performing systematically and quantitatively the design and evaluation processes of spindle system under the windows GUI environment. Also, to enhance the user-friendliness, “SpindleX” possesses the various additional functions such as the DXF file interface for auto-importing the shape and geometric data of spindle system from the DXF file, the bearing database for auto-importing the mechanical properties and geometric data of bearing by the bearing number, and the graphical visualization for certificating the imported and analysed data of spindle system.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.159-162
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• 2000

The purpose of this study is to develope an accurate procedure for measuring the glass content of fly ash produced by bituminous coal to assist in predicting their behavior in concrete. Quantitative mineralogical compositions of fly ashes were obtained by internal standard method using powder X-ray diffraction analysis. In the X-ray diffraction method, the specimen and standard fluorite were cautiously mixed and pulverized to 22$\mu$m in wet process so as to avoid the prefered orientation of the crystal and microabsorption effect of X-ray. calibration curve were fitted for several references peaks of four phases:$\alpha$-quartz. mullite, magnetite, hematite. The amount of glass was calculated by subtracting the amount of crystal phase and loss on ignition from the total amount. Glass content determined with this method ranged from 66.7 to 75.wt%.

• Journal of the Korean Mathematical Society
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• v.40 no.3
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• pp.409-422
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• 2003

Let $F: \mathbb{C}^k\;{\rightarrow}\;\mathbb{C}^k$ be a dynamical system and let $\{x_n\}_{n{\geq}0}$ denote an orbit of F. We study the relation between $\{x_n\}$ and pseudoorbits $\{y_n}, y_0=x_0.\;Here\;y_{n+1}=F(y_n)+s_n.$ In general $y_n$ might diverge away from $x_n.$ Our main problem is whether there exists arbitrarily small $t_n$ so that if $\tilde{y}_{n+1}=F(\tilde{y}_n)+s_n+t_n,$ then $\tilde{y}_n$ remains close to $x_n.$ This leads naturally to the concept of sustainable orbits, and their existence seems to be closely related to the concept of hyperbolicity, although they are not in general equivalent.

• Bulletin of the Korean Mathematical Society
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• v.27 no.2
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• pp.127-131
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• 1990

Let f:R.rarw.R be a continuous function on the real line R, and denote the n-th iterate of f by f$^{n}$ :f$^{1}$=f and f$^{n}$ =f.f$^{n-1}$ for n>1. A point x.mem.R is a periodic point of f of period k>0 if f$^{k}$ (x)=x but f$^{i}$ (x).neq.x for all 01, then it must also have a fixed point, by the intermediate Theorem. Also the question has an intriguing answer which was found by ths Russian mathematician Sharkovky [6] in 1964.